WO2025093990A1

WO2025093990A1 - Systems for anchoring in tissue

Info

Publication number: WO2025093990A1
Application number: PCT/IB2024/060377
Authority: WO
Inventors: Jacob Timothy MORRISON; Michael G VALDEZ; Sergio DELGADO; Tiana TRAN; Mauricio GUERRERO; Asher L METCHIK; Travis Zenyo OBA; Henry Thek Chan; Christopher Rene WILLIAMS; Alex Raymond DIEHL; Samuel Jacob KIPPERMAN; David Nathaniel SWARTZ; Sirous Darabian
Original assignee: Edwards Lifesciences Innovation Israel Ltd
Current assignee: Edwards Lifesciences Innovation Israel Ltd
Priority date: 2023-10-31
Filing date: 2024-10-22
Publication date: 2025-05-08
Anticipated expiration: 2026-04-30

Abstract

A system comprises a driver (18), and an anchor (10). The anchor comprises a head (16) engageable by the driver; and a tissue-engaging element (12). The tissue-engaging element comprises a tubular member (13), and a wire (14). The tubular member defines a lumen therealong, is fixed to the head, and extends away from the head to a distal tip of the tubular member. The wire comprises a shape-set end that, within the lumen, is constrained away from its set shape. The driver is configured, via engagement with the head, to anchor the anchor to the tissue by inserting the tubular member into the tissue, and pushing the wire through the tubular lumen such that the shape-set end becomes exposed from the tubular member and relaxes toward its set shape. Other embodiments are also disclosed.

Description

SYSTEMS AND METHODS FOR ANCHORING

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application claims priority to Provisional US Patent Application 63/594,934 to Morrison et al., filed 31 October 2023, and to Provisional US Patent Application 63/648,596 to Morrison et al., filed 16 May 2024.

[0002] Each of the above documents is incorporated herein by reference.

BACKGROUND

[0003] Tissue anchors may eventually become dislodged due to constant motion of the tissue in a beating heart. Dislodged tissue anchors may further cause an implant, which the tissue anchors are intended to anchor into the tissue, to become loose such that the implant fails to perform its intended function. Dislodged anchors may also create a danger of embolism.

SUMMARY

[0004] This summary is meant to provide some examples and is not intended to limit the scope of the disclosure in any way. For example, any feature included in an example of this summary is not required by the claims, unless the claims explicitly recite the features. Also, the features, components, steps, concepts, etc. described in examples in this summary and elsewhere in this disclosure can be combined in a variety of ways. Various features and steps as described elsewhere in this disclosure can be included in the examples summarized here.

[0005] Some example implementations described herein are directed towards systems, apparatuses, devices, and methods to inhibit unintended retraction from tissue (e.g., unintended unscrewing of anchors from tissue) into which they have been implanted. For example, tissue anchors having multiple elements are described.

[0006] Some tissue anchors herein are described as having helical tissue-engaging elements, but generally various other types of tissue-engaging elements are also possible, e.g., darts, hooks, lances, barbs, etc.

[0007] In accordance with some implementations, a system for anchoring, which can be used in a tissue of a subject and/or a simulation, includes a driver and/or an anchor. In some implementations, the anchor includes a head, a tissue-engaging element, and/or a wire. In some implementations, the head is engageable by the driver.

[0008] In some implementations, the tissue-engaging element includes a tubular member, e.g., a tubular helical member (though other configurations of tissue-engaging elements are also possible) and/or the wire (or other component). In some implementations, the tubular helical member defines a helical lumen therealong, the tubular helical member being fixed to the head, and extending away from the head to a distal tip of the tubular helical member.

[0009] In some implementations, the wire has a shape-set end that has a set shape. In some implementations, the shape- set end is constrained away from its set shape within the helical lumen.

[0010] In some implementations, the driver is configured, via engagement with the head, to anchor the anchor to the tissue by screwing the tubular helical member into the tissue, and/or by pushing the wire through the helical lumen such that the shape-set end becomes exposed from the tubular helical member and relaxes toward its set shape.

[0011] In some implementations, the wire can comprise and/or be formed from nitinol. In some implementations, the shape-set end, in its set shape, has a greater curvature than when constrained within the helical lumen. In some implementations, the shape-set end, in its set shape, has a lesser curvature than when constrained within the helical lumen. In some implementations, the shape-set end is biased to curve in a direction opposite to that of a handedness of the tubular helical member.

[0012] In some implementations, the helical lumen opens at the distal tip, and the shapeset end of the wire exits the helical lumen at the distal tip.

[0013] In some implementations, the anchor defines a proximal opening into the helical lumen, and/or the wire defines a stop at a proximal end of the wire, the stop being wider than the proximal opening, thereby preventing the stop from passing beyond the proximal opening and into the lumen.

[0014] In accordance with some implementations, a system and/or an apparatus, which can be used with a tissue of a subject (e.g., a live subject and/or a simulation), includes an anchor. In some implementations, the anchor includes a tissue-engaging element and a head. [0015] In some implementations, the tissue engaging element is a helical tissue-engaging element. In some implementations, the helical tissue-engaging element defines a proximal end and a distal tip, and defines an anchor axis of the anchor.

[0016] In some implementations, the head includes a base and a grip-body. In some implementations, the base is coupled to the proximal end and comprises an interface, and/or multiple petals extending laterally away from the anchor axis; and/or a neck extending axially between the interface and the petals.

[0017] The grip-body can be configured in a wide variety of ways, including the same as or similar to any grip-body, platform, and/or foot herein. In some implementations, the gripbody comprises multiple friction features or grips, e.g., grip-body lobes, extending laterally away from the anchor axis, the grip-body being rotatably mounted on the neck. In some implementations, each of the friction features or grips is associated with a respective petal.

[0018] In some implementations, the base is fixed to the tissue-engaging element such that, via application of torque to the interface, the tissue-engaging element is screwable along the anchor axis into the tissue in a manner that brings the petals into contact with the tissue.

[0019] In some implementations, the petals extend laterally from the anchor axis at least as far as do the grips. In some implementations, the grips are disposed axially between the interface and the petals.

[0020] In some implementations, the grip-body is disposed axially between the interface and the petals.

[0021] In some implementations, the system further includes a driver, reversibly engageable with the interface in order to apply the torque to the interface.

[0022] In some implementations, the anchor is configured such that screwing the tissueengaging element along the anchor axis into the tissue in the manner that brings the petals into contact with the tissue also brings the friction features or grips into contact with the tissue.

[0023] In some implementations, the system further includes a driver configured to engage the interface and apply the torque to the interface. In some implementations, the driver is configured to unscrew the tissue-engaging element from the tissue by applying reverse torque to the interface. [0024] In some implementations, each of the grip-body lobes has a grip configured to grip the tissue.

[0025] In some implementations, the head has a first state in which the petals are positioned with respect to the grip-body such that screwing the helical tissue-engaging element along the anchor axis into the tissue brings the petals and the grip of each grip-body lobe into contact with the tissue, and/or the grips, once in contact with the tissue, inhibit unscrewing of the tissue-engaging element from the tissue. In some implementations, the head has a second state in which each petal is positioned with respect to the grip-body in a manner that obscures the grip of the respective grip-body lobe, and/or via application of reverse torque to the interface, the tissue-engaging element is unscrewable along the anchor axis out of the tissue.

[0026] In some implementations, in the first state, the grip extends beyond an edge of the respective petal. In some implementations, the grip-body lobes inhibit unscrewing of the tissue-engaging element from the tissue by having a grip-directionality opposite that of the helical tissue-engaging element. In some implementations, the tissue-engaging element is configured to be screwed into the tissue while the anchor is in the first state; and/or the head is configured to transition into the second state responsively to the application of the reverse torque to the interface.

[0027] In some implementations, the head is configured to transition into the second state by rotation of the base with respect to the grip-body responsive to the application of the reverse torque to the interface.

[0028] In some implementations, the grip-body and at least one of the petals collectively define a coupling that includes a protrusion and an indentation on mutually-facing surfaces of the head; and/or in the first state, the protrusion is disposed in the indentation in a manner that inhibits transitioning of the head from the first state toward the second state. In some implementations, in the first state of the anchor, the coupling inhibits rotation of the base with respect to the grip-body.

[0029] In some implementations, the coupling defines a threshold relative-rev erse-torque between the base and the grip-body, and is configured to release the head to transition from the first state toward the second state by the protrusion moving out of the indentation responsively to relative-reverse-torque between the base and the grip-body exceeding the threshold relative-reverse-torque. [0030] In some implementations, the petals are defined by a plate, the plate comprising a stop that limits an extent of rotation of the grip-body in the second direction.

[0031] In some implementations, via application of the reverse torque to the interface, the anchor is unscrewable along the anchor axis out of the tissue in a manner that the contact between the grips and the tissue releases the protrusion from the indentation, such that the anchor transitions from the first state to the second state by rotation of the base with respect to the grip-body.

[0032] In some implementations, the grip-body reaches the limit of the extent of rotation of the grip-body with respect to the plate, such that the grip-body abuts the stop. In some implementations, the petal is positioned in the manner that obscures the grip of the respective grip-body lobe.

[0033] In accordance with some implementations, an anchor (which can be part of any of the systems or apparatus herein) for use at a tissue of a heart of a subject (e.g., living subject and/or a simulation) comprises a head and a tissue-engaging element, extending from the head.

[0034] In some implementations, the anchor comprises a grip-body, platform, or foot. In some implementations, the grip-body, platform, or foot comprises a tissue-facing surface facing distally away from the head.

[0035] In some implementations, the grip-body, platform, or foot comprises an opening through which at least a portion of the tissue-engaging element can pass, such that, as the tissue-engaging element is inserted into tissue, the grip-body, platform, or foot can move along a portion of the tissue-engaging element.

[0036] In some implementations, the anchor comprises a spring, mounted such that, when the grip-body, platform, or foot is engaged with the tissue and the tissue-engaging element is inserted into the tissue, the spring can compress between the head and the grip-body, platform or foot.

[0037] In some implementations, the tissue-engaging element and the spring are coaxial.

[0038] In some implementations, the tissue-engaging element is disposed coaxially inside of the spring. [0039] In some implementations, the spring has a constant selected such that the spring exerts pressure on the grip-body, platform, or foot as the tissue-engaging element is inserted into the tissue.

[0040] In some implementations, the anchor is configured such that pressure exerted by the spring on the grip-body, platform, or foot can help stabilize the tissue-engaging element as the tissue-engaging element is inserted into the tissue.

[0041] In some implementations, the anchor is configured such that pressure exerted by the spring on the grip-body, platform, or foot can help stabilize the tissue-engaging element at various depths of insertion into the tissue.

[0042] In some implementations, the anchor is configured such that pressure exerted by the spring on the grip-body, platform, or foot can help stabilize the tissue-engaging element after completion of insertion into the tissue to a final depth.

[0043] In some implementations, the grip-body, platform, or foot defines friction features on the tissue-facing surface.

[0044] In some implementations, the friction features comprise a set of cleats.

[0045] In some implementations, the friction features comprise a series of corrugated ridges. Other types of friction features are also possible.

[0046] In accordance with some implementations, a system and/or an apparatus, which can be used with a tissue of a subject (e.g., a live subject and/or a simulation), includes an anchor. In some implementations, the anchor includes a tissue-engaging element and a head.

[0047] In some implementations, the tissue-engaging element is a helical tissue-engaging element. In some implementations, the helical tissue-engaging element includes a proximal end and a distal tip, and defines an anchor axis of the anchor.

[0048] In some implementations, the head includes a base and a grip-body (which can be the same as or similar to other grip-bodies, platforms, or feet herein). In some implementations, the base is coupled to the proximal end and shaped to define an interface. In some implementations, the base is fixed to the tissue-engaging element such that, via application of torque to the interface while the head is in a first state, the tissue-engaging element is screwable along the anchor axis into the tissue in a manner that brings the grip into contact with the tissue. By gripping the tissue, the grip inhibits unscrewing of the tissueengaging element from the tissue. [0049] In some implementations, the head is further configured to facilitate unscrewing of the tissue-engaging element from the tissue responsively to application of reverse torque to the interface by, responsively to application of the reverse torque to the interface, transitioning into a second state via movement of the base with respect to the grip-body. In the second state, the base is configured to separate the grip from the tissue by interposing between the grip and the tissue.

[0050] In some implementations, the interface is fixedly coupled to the tissue-engaging element. In some implementations, the grip is rotatably coupled to the base. In some implementations, the movement is rotation.

[0051] In some implementations, the base and the grip collectively define a coupling that includes a protrusion and an indentation on mutually-facing surfaces of the head and grip, respectively. In some implementations, the coupling is associated with a threshold relative- reverse-torque between the base and the grip.

[0052] In some implementations, the coupling is configured to inhibit transitioning of the head from the first state toward the second state while reverse torque applied by the base to the grip is below the threshold relative-reverse-torque.

[0053] In some implementations, the coupling is configured to release the head to transition from the first state toward the second state by the protrusion moving out of the indentation responsive to the application of reverse torque to the interface causing the reverse torque applied by the base to the grip to exceed the threshold reverse torque.

[0054] In some implementations, a part of the base is disposed axially between the grip and the tissue-engaging element, the part interposing between the grip and the tissue. In some implementations, the part is fixedly coupled to the interface. In some implementations, the part is fixedly coupled to the tissue-engaging element.

[0055] In accordance with some implementations, a system and/or an apparatus for anchoring in a tissue of a subject and/or tissue of a simulation includes an anchor. In some implementations, the anchor includes a tissue-engaging element having a proximal end, and defining a longitudinal anchor axis of the anchor; and/or a head assembly.

[0056] In some implementations, the head assembly includes a head that comprises an interface that is fixed to the proximal end via a coupling that is eccentric with respect to the anchor axis. [0057] In some implementations, the interface is fixed to the proximal end such that the tissue-engaging element is screwable into the tissue via application of torque to the interface, and/or a collar, and/or a driver.

[0058] In some implementations, the collar defines a laterally -oriented eyelet, and/or is rotatably coupled to the proximal end.

[0059] In some implementations, the driver is configured to engage and apply the torque to the interface.

[0060] In some implementations, the collar is disposed between the head and the proximal end. In some implementations, the head defines a circumference, and the anchor is configured such that the application of the torque to the interface by the driver rotates the head and the tissue-engaging element while the collar periodically extends beyond the circumference.

[0061] In some implementations, while the interface is engaged by the driver, applying torque to the interface rotates the head and the helical tissue-engaging element. In some implementations, the coupling is eccentric with respect to the head. In some implementations, the eccentricity of the coupling with respect to the anchor axis is provided by the proximal end being eccentric to the anchor axis.

[0062] In some implementations, the interface includes a central slot via which the driver is configured to apply the torque. In some implementations, the eyelet is configured to allow passage of a wire in a manner that applying tension to the wire maintains the collar in a fixed orientation with respect to the anchor axis. In some implementations, while the interface is engaged by the driver and the wire is under tension, the head rotates with respect to the collar.

[0063] In some implementations, the anchor axis is disposed along a center of the helical tissue-engaging element; and/or the proximal end defines a shaft that is parallel to the anchor axis and eccentric with respect to the anchor axis.

[0064] In some implementations, the collar is rotatably coupled to the proximal end by the shaft extending through the collar. In some implementations, the shaft is eccentric with respect to the collar. In some implementations, the eyelet is transverse with respect to the shaft. [0065] In some implementations, the head includes a recess in a perimeter thereof, within which an upper aspect of the collar is configured to rotate.

[0066] In some implementations, the collar has a tapered surface, and is rotatably coupled to the proximal end such that rotation of the collar with respect to the head slides the tapered surface under the head.

[0067] In accordance with some implementations, an apparatus, (e.g., usable and/or for use in a heart of a subject) includes an anchor that includes a tissue-engaging element, a head, and/or a collar. In some implementations, the tissue-engaging element defines an anchor axis of the anchor.

[0068] In some implementations, the head defines an interface, and/or is fixed to the proximal end such that the tissue-engaging element is screwable into tissue of the heart via application of torque to the interface.

[0069] In some implementations, the collar defines a laterally-oriented eyelet, and coupled to the proximal end such that the collar is rotatable around a collar axis that is lateral to, and parallel with, the longitudinal axis.

[0070] In accordance with some implementations, a method for anchoring, which can be used in a valve of a heart of a subject and/or of a simulation includes advancing multiple anchors to the heart. In some implementations, each anchor includes a tissue-engaging element, a head, and/or a collar. In some implementations, the tissue-engaging element defines an anchor axis of the anchor.

[0071] In some implementations, the head is configured to be fixed to a proximal end of the tissue-engaging element.

[0072] In some implementations, the collar defines a laterally -oriented eyelet, and/or is coupled to the proximal end such that the collar is rotatable around a collar axis. In some implementations, the collar axis is lateral to, and parallel with, the anchor axis.

[0073] In some implementations, the method further comprises using a driver, anchoring the tissue-engaging element of each anchor within an annulus of the valve.

[0074] In some implementations, the method further comprises within the heart, applying tension to a wire that is threaded through the eyelet of each collar. [0075] In some implementations, the wire is threaded through the eyelet such that the wire draws the anchors toward each other, and/or pulls the eyelet of at least one of the anchors to rotate around the collar axis and away from the anchor axis.

[0076] In some implementations, applying tension to the wire includes applying tension to the wire in a manner that draws the anchors medially with respect to a curve defined by the wire in response to anchoring the anchors around the valve.

[0077] In some implementations, the method further includes applying torque to the head in a manner that the tissue-engaging element rotates into the tissue along the anchor axis while the collar rotates around the collar axis.

[0078] In some implementations, advancing the multiple anchors includes advancing the multiple anchors through a catheter to the heart. In some implementations, the collar includes a beveled surface facing the head, and/or the method further includes, for at least one of the multiple anchors, subsequently to anchoring the tissue-engaging element within the valve, moving the catheter distally over the head and against the beveled surface in a manner that rotates the collar around the collar axis toward the anchor axis, and/or using the driver, deanchoring the tissue-engaging element from the tissue.

[0079] In accordance with some implementations, a system for anchoring in a real or simulated tissue includes a delivery tool and an anchor. In some implementations, the anchor includes a head, and/or a tissue-engaging element, extending distally from the head to define an anchor axis of the anchor.

[0080] In some implementations, the system includes a stabilizer. In some implementations, the stabilizer is defined by a resilient wire having a first end that is fixedly coupled to the head.

[0081] In some implementations, the delivery tool is configured to deliver the anchor to the tissue. In some implementations, the delivery tool is configured to deliver the anchor to the tissue while the wire is constrained around the head, a free end of the wire being biased to deflect laterally from the head responsively to deployment from the delivery tool.

[0082] In some implementations, the stabilizer is configured, upon deployment from the delivery tool, to at least partially unwrap from a coiled position in which it was disposed within the delivery tool, such that the stabilizer extends beyond a lateral extent of the helical tissue-engaging element. [0083] In some implementations, the stabilizer is biased to deflect laterally from the head beyond a lateral extent of the helical tissue-engaging element. In some implementations, the stabilizer includes an elastic material, and is constrained within the delivery tool during delivery.

[0084] In some implementations, responsively to deployment from the delivery tool, the stabilizer deflects laterally away from the head. In some implementations, in a deployed state, the stabilizer is substantially planar, such that when the anchor is deployed into the tissue, the stabilizer rests on a surface of the tissue. In some implementations, in a delivery state, the stabilizer extends at least 180 degrees around the head.

[0085] In some implementations, in a delivery state, the stabilizer extends less than 360 degrees around the head. In some implementations, in a deployed state, the stabilizer extends at least 180 degrees around the head. In some implementations, in a deployed state, the stabilizer extends at least 220 degrees around the head. In some implementations, in a deployed state, the stabilizer extends less than 300 degrees around the head. In some implementations, in a deployed state, the stabilizer extends less than 280 degrees around the head.

[0086] In some implementations, the head includes an eyelet, and/or the stabilizer is rotatably fixed with respect to the eyelet, such that when the stabilizer deflects laterally from the head, the stabilizer is circumferentially oriented with respect to the eyelet.

[0087] In some implementations, the system includes a tether threaded through the eyelet, the tether configured to exert a lateral force on the eyelet in a manner that would bias the anchor to tilt in a direction of the exerted lateral force. In some implementations, the stabilizer is configured to advantageously inhibit tilting of the anchor in the direction of the exerted lateral force. In some implementations, the stabilizer is biased to deflect laterally from the head beyond a lateral extent of the eyelet.

[0088] In accordance with some implementations, a system for use at a real or simulated tissue of a real or simulated subject includes an anchor that includes a head, and/or a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue.

[0089] In some implementations, at a distal end of the tissue-engaging element, a distal pair of adjacent helical turns of the series has a first inter-tum gap therebetween, and/or proximal from the distal pair, a proximal pair of adjacent helical turns of the series has a second inter-turn gap therebetween, the second inter-turn gap being smaller than the first inter-turn gap.

[0090] In some implementations, the tissue-engaging element has a helix diameter that is constant along the series of helical turns. In some implementations, the tissue-engaging element has a gauge that is greater at the proximal pair than at the distal pair.

[0091] In some implementations, the tissue-engaging element has a pitch that is constant along the series of helical turns.

[0092] In some implementations, the second inter-turn gap is smaller than the first interturn gap by 1 mm, 1.5 mm, or 2 mm. In some implementations, the second inter-tum gap is smaller than the first inter-turn gap by 10%, 20%, 30%, 40%, or 50%.

[0093] In some implementations, the tissue-engaging element has a pitch that is smaller at the proximal pair than at the distal pair.

[0094] In some implementations, the tissue-engaging element has a gauge that is constant along the series of helical turns. In some implementations, the second inter-tum gap is smaller than the first inter-tum gap by 1 mm, 1.5 mm, or 2 mm. In some implementations, the second inter-turn gap is smaller than the first inter-turn gap by 10%, 20%, 30%, 40%, or 50%.

[0095] In some implementations, the head defines an interface, and/or the system further includes a driver configured to, via engagement with the interface, screw the tissue-engaging element into the tissue such that a first amount of screwing of the tissue-engaging element into the tissue captures a part of the tissue in the distal inter-tum gap. Further screwing of the tissue-engaging element into the tissue places the part of the tissue in the proximal interturn gap, such that the part of the tissue becomes compressed between the proximal pair of adjacent helical turns.

[0096] In some implementations, the series of helical turns includes, proximal from the proximal pair of adjacent helical turns, an other pair of adjacent helical turns of the series, the other pair of adjacent helical turns having an other inter-turn gap therebetween, the other inter-turn gap being greater than the proximal inter-turn gap. In some implementations, the proximal pair of adjacent helical turns is located in a midsection of the series of helical turns. [0097] In some implementations, the proximal pair of adjacent helical turns is located at a proximal end of the series of helical turns.

[0098] In some implementations, the helical tissue-engaging element includes a wire, a midsection of the wire being thicker than the proximal end. In some implementations, the helical tissue-engaging element includes a wire, a midsection of the wire being thicker than the distal end.

[0099] In accordance with some implementations, a system for use at a real or simulated tissue of a real or simulated subject includes an anchor that includes a head, and/or a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue. In some implementations, a first pair of adjacent helical turns of the series has a first pitch, and/or distal from the first pair, a second pair of adjacent helical turns of the series has a second pitch, the second pitch being greater than the first pitch.

[0100] In accordance with some implementations, a system for use at a real or simulated tissue of a real or simulated subject includes an anchor that includes a head, and/or a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue. In some implementations, a first pair of adjacent helical turns of the series has a first gauge, and/or proximal from the first pair, a second pair of adjacent helical turns of the series has a second gauge. In some implementations, the second gauge is greater than the first gauge, and a pitch of the tissue-engaging element is constant along a length of the series.

[0101] In accordance with some implementations, a system for anchoring in a real or simulated tissue of a real or simulated subject includes an anchor, that includes a head including an interface; and/or areal or simulated tissue-engaging element extending helically away from the head. In some implementations, the tissue-engaging element defines a helical channel therealong, the tissue-engaging element having a pitch; and/or a wire extends along the helical channel. In some implementations, a driver is configured, via engagement with the head, to anchor the anchor to the tissue by screwing the tissue-engaging element into the tissue, and/or subsequently, reducing the pitch of the tissue-engaging element by extracting the wire from the helical channel. [0102] In some implementations, the tissue-engaging element is elastically deformable. In some implementations, the tissue-engaging element is plastically deformable. In some implementations, the wire is shaped as a series of coils having a pitch greater than the pitch of the tissue-engaging element.

[0103] In some implementations, the wire is configured to remain within the helical channel after anchoring of the anchor to the tissue. In some implementations, the wire is configured to be removed from the anchor after anchoring of the anchor to the tissue. In some implementations, the helical channel includes a groove running along an inner curve of the tissue-engaging element.

[0104] In some implementations, the wire is a coiled wire. In some implementations, the driver includes a rod within a tube, the rod engaging the interface, and the tube coupled to the coiled wire. In some implementations, the driver is configured to screw the tissueengaging element into the tissue while the coiled wire extends distally from the tube along the helical channel.

[0105] In some implementations, the tube is configured to retract from the tissue in a manner that unscrews the coiled wire from within the helical channel, such that the tissueengaging element relaxes within the tissue into a shape having the reduced pitch.

[0106] In some implementations, the wire defines a stiff inner coil within an outer coil defined by the tissue-engaging element, the outer coil being an elastically deformable tube including a shape-set material, and/or biased toward a shape-set pitch less than that of the inner coil.

[0107] In some implementations, the head includes an interface, and the driver includes an interface-engaging rod and a tube through which the rod is configured to pass, the tube fixedly coupled to the stiff inner coil. In some implementations, the outer coil includes a shape-set material defining a compressed set shape; and/or the inner coil includes a shapeset material defining an extended set shape.

[0108] In some implementations, the inner coil extends through the helical lumen, and/or maintains the tissue-engaging element in the extended set shape. In some implementations, extracting the inner coil proximally through the helical lumen relaxes the outer coils of the tissue-engaging element to assume the compressed set shape.

[0109] In accordance with some implementations, a system for anchoring in a real or simulated tissue of areal or simulated subject includes an anchor, that includes ahead; and/or a real or simulated tissue-engaging element extending helically away from the head. In some implementations, the tissue-engaging element defines a helical lumen therealong, and/or the tissue-engaging element defines a first pitch.

[0110] In some implementations, a wire extends along the helical lumen.

[0111] In some implementations, a driver is configured, via engagement with the head, to anchor the anchor to the tissue by screwing the tissue-engaging element into the tissue, and/or subsequently, plastically deforming the tissue-engaging element to have a reduced pitch by applying tension to the wire.

[0112] In some implementations, the wire is configured to remain attached to a distal tip of the tissue-engaging element after the driver is detached from the anchor. In some implementations, upon the driver applying proximal tension to the wire, the wire is configured to detach from a distal tip of the tissue-engaging element.

[0113] In accordance with some implementations, a system for anchoring in a real or simulated tissue includes an anchor, that includes a head; and/or a helical tissue-engaging element. In some implementations, the tissue-engaging element is configured to be screwed into the tissue, and/or defines a helical channel therealong, and/or is biased toward having a first pitch. In some implementations, a wire extends helically along the helical channel in a manner that constrains the helical tissue-engaging element to have a second pitch that is greater than the first pitch.

[0114] In some implementations, the helically-extending wire is shaped as a fixed series of coils having the second pitch. In some implementations, the helical channel defines a lumen. In some implementations, the helical channel defines a groove running along an inside aspect of the helical tissue-engaging element. In some implementations, the second pitch is greater than the first pitch.

[0115] In some implementations, the system further includes a driver configured, via engagement with the head, to anchor the anchor to the tissue. In some implementations, the driver screws the tissue-engaging element into the tissue, and/or subsequently, restores the first pitch to the tissue-engaging element by extracting the wire from the helical channel.

[0116] In some implementations, the wire is a component of the driver. In some implementations, the wire is a component of the anchor, the driver being configured to engage the anchor by engaging both the head and the wire. [0117] In accordance with some implementations, a system for anchoring in a real or simulated tissue of a real or simulated subject includes an anchor that includes a head, and/or an outer helical tissue-engaging element. In some implementations, the outer tissueengaging element extends helically away from the head, and defines a helical channel therealong.

[0118] In some implementations, the outer tissue-engaging element is biased toward a first pitch. In some implementations, the anchor further comprises an inner helical element disposed along the helical channel, the inner helical element defining a second pitch that is greater than the first pitch.

[0119] In some implementations, the system further comprises a driver configured, via engagement with the head, to anchor the anchor to the tissue by screwing the outer helical tissue-engaging element and the inner helical element into the tissue while the inner helical element remains disposed along the helical channel, and/or subsequently, triggering the outer helical tissue-engaging element to transition toward the first pitch by extracting the inner helical element from the helical channel and the tissue.

[0120] In some implementations, the inner helical element is stiffer than the helical tissueengaging element. In some implementations, a thickness of the inner helical element is greater than half a thickness of the outer tissue-engaging element.

[0121] In accordance with some implementations, a method for use with real or simulated cardiovascular tissue of a real or simulated subject includes transluminally advancing an anchor to the tissue, the anchor having a helical tissue-engaging element that defines a pitch. In some implementations, the method further includes subsequently, screwing the helical tissue-engaging element of the anchor into the tissue; and/or while the tissue-engaging element remains screwed into the tissue, reducing the pitch of the tissue-engaging element.

[0122] In some implementations, the method further includes, while a coiled wire is disposed along a helical channel defined by the helical tissue-engaging element, screwing the helical tissue-engaging element into the tissue by engagement of a head of the anchor with a driver. In some implementations, the method further includes disengaging the driver from the tissue in a manner that removes the coiled wire from within the helical tissueengaging element, thereby reducing the pitch of the tissue-engaging element.

[0123] In some implementations, the method further includes disengaging the driver from the head. [0124] In some implementations, the method further includes sterilizing the anchor.

[0125] In accordance with some implementations, a system for anchoring in a real or simulated tissue of a real or simulated subject includes an anchor. In some implementations, the anchor includes a head; and/or a real or simulated tissue-engaging element, extending away from the head, having a first shape.

[0126] In some implementations, the tissue-engaging element is formed from a shape memory material that has a transition temperature of below 37 degrees Celsius such that, upon reaching the transition temperature, the tissue-engaging element transitions away from the first shape and toward a pre-defined set shape.

[0127] In some implementations, the system includes a delivery tool that includes a catheter, transluminally advanceable to the tissue; and/or a driver, configured to advance the anchor through the catheter to the tissue. In some implementations, the delivery tool is configured, while the driver advances the anchor through the catheter, to maintain the tissueengaging element in the first shape by maintaining the tissue-engaging element below the transition temperature by streaming a fluid through the catheter to the anchor. In some implementations, the driver is configured, via engagement with the head, to drive the tissueengaging element into the tissue while the tissue-engaging element remains in the first shape.

[0128] In some implementations, during advancement of the catheter to the tissue, the streaming fluid is maintained at a temperature below the transition temperature. In some implementations, the temperature of the fluid is maintained below 37 degrees Celsius. In some implementations, the fluid includes normal saline. In some implementations, upon being driven into the tissue, the tissue-engaging element is configured to assume the predefined set shape.

[0129] In accordance with some implementations, a system for use at a real or simulated tissue of a real or simulated heart of a real or simulated subject includes an anchor. In some implementations, the anchor includes a head; and/or a helical tissue-engaging element. In some implementations, the helical tissue-engaging element extends distally from the head to define an anchor axis of the anchor.

[0130] In some implementations, the anchor further includes a grip configured as a foot. In some implementations, the foot defines a real or simulated tissue-facing surface facing distally away from the head. In some implementations, the foot further defines a thread, complementary to and threadedly engaged with the tissue-engaging element, the tissue- engaging element being configured to be screwed distally along the thread and into the tissue by torque applied to the head. In some implementations, the anchor further defines a spring, mounted such that screwing of the tissue-engaging element distally along the thread compresses the spring between the head and the foot.

[0131] In some implementations, the tissue-engaging element and the spring are coaxial. In some implementations, the tissue-engaging element is disposed coaxially inside of the spring. In some implementations, the spring has a constant selected such that the spring exerts pressure on the foot as the helical tissue-engaging element is screwed into the tissue.

[0132] In some implementations, pressure exerted by the spring on the foot stabilizes the helical tissue-engaging element as the helical tissue-engaging element is screwed into the tissue. In some implementations, pressure exerted by the spring on the foot stabilizes the helical tissue-engaging element when the helical tissue-engaging element is fully screwed into the tissue or screwed into the tissue to a selected or desired depth.

[0133] In some implementations, the foot defines grips on the tissue-facing surface. In some implementations, the grips include a set of cleats. In some implementations, the grips include a series of corrugated ridges.

[0134] In accordance with some implementations, a method for use at a real or simulated tissue of a real or simulated subject includes advancing a first anchor and a second anchor to the tissue, the first anchor including (i) a first head, and (ii) a first helical tissue-engaging element extending from the first head, and the second anchor including (i) a second head, and (ii) a second helical tissue-engaging element extending from the first head.

[0135] In some implementations, the method further includes screwing the first helical tissue-engaging element into the tissue. In some implementations, the method further includes screwing the second helical tissue-engaging element into the tissue at an oblique angle with respect to the first tissue-engaging element, such that at least one turn of the second helical tissue-engaging element hooks around at least one turn of the first helical tissue-engaging element within the tissue.

[0136] In some implementations, the method further includes disengaging the driver from the tissue and removing the driver from the subject.

[0137] In some implementations, the method further includes sterilizing the first anchor and the second anchor. [0138] In some implementations, the first tissue-engaging element defines a first anchor axis, and/or the second tissue-engaging element defines a second anchor axis. In some implementations, screwing the second helical tissue-engaging element into the tissue at an oblique angle with respect to the first tissue-engaging element includes screwing the second helical tissue-engaging element into the tissue along the second anchor axis at an oblique angle with respect to the first anchor axis.

[0139] In some implementations, screwing the first helical tissue-engaging element and the second helical tissue-engaging element into the tissue includes providing a driver having a first driver interface and a second driver interface, such that screwing the first helical tissueengaging element into the tissue is performed using the first driver interface, and screwing the second helical tissue-engaging element into the tissue is performed using the second driver interface.

[0140] In some implementations, screwing the second helical tissue-engaging element into the tissue at the oblique angle includes orienting the second driver interface at the oblique angle before screwing the first anchor into the tissue using the first driver interface, such that screwing the second helical tissue-engaging element into the tissue by the second driver interface occurs along a trajectory that intersects with the first anchor.

[0141] In accordance with some implementations, a method for use at a real or simulated tissue of a real or simulated subject includes advancing an anchor to the tissue, the anchor including (i) a head, and (ii) a first tissue-engaging element extending from the first head to define an anchor axis of the anchor. In some implementations, he method further includes driving the first tissue-engaging element along the anchor axis into the tissue. In some implementations, the method further includes locking the first tissue-engaging element in the tissue by driving a second tissue-engaging element into the tissue such that, within the tissue, the second tissue-engaging element engages the first tissue-engaging element.

[0142] In accordance with some implementations, a system for anchoring in a real or simulated tissue includes a delivery tool, including a first driver and a second driver. The system further includes a first anchor. In some implementations, the first anchor includes a first head, engageable by the driver; and a first helical tissue-engaging element extending distally from the first head. [0143] In some implementations, the system further includes a second anchor. In some implementations, the second anchor includes a second head, engageable by the driver; and a second helical tissue-engaging element, extending distally from the second head.

[0144] In some implementations, the delivery tool is configured to use the first driver to advance the first tissue-engaging element into the tissue. In some implementations, the delivery tool is further configured to use the second driver to advance the second tissueengaging element into the tissue at an oblique angle with respect to the first tissue-engaging element, such that at least one turn of the second helical tissue-engaging element hooks around at least one turn of the first helical tissue-engaging element within the tissue.

[0145] In some implementations, the first tissue-engaging element has a handedness opposite to a handedness of the second tissue-engaging element. In some implementations, the first tissue-engaging element and the second tissue-engaging element have a same handedness.

[0146] In accordance with some implementations, a system for anchoring in a real or simulated tissue includes a driver and an anchor. In some implementations, the anchor includes a screw, that defines a head, engageable by the driver.

[0147] In some implementations, the anchor further includes a helical tissue-engaging element, extending away from the head to define an anchor axis of the anchor, the screw defining an eccentric hole.

[0148] In some implementations, the anchor further includes a locking pin.

[0149] In some implementations, the driver is configured to screw the tissue-engaging element into the tissue by applying torque to the head. In some implementations, the driver is further configured to lock the tissue-engaging element in the tissue by driving the locking pin into the tissue and through the eccentric hole in the screw.

[0150] In some implementations, the locking pin is eccentric to the anchor axis. In some implementations, the locking pin is parallel to the anchor axis. In some implementations, the locking pin is oblique to the anchor axis. In some implementations, the pin includes a set of unidirectional tabs configured to enable passage of the pin through the hole in a first direction. In some implementations, the tabs are configured to prevent passage of the pin through the hole in a second direction. [0151] In some implementations, the head further includes a tab fixedly attached thereto, and the hole is disposed in the tab lateral to the anchor axis. In some implementations, the hole aligns with a series of holes in sequential turns of the helical tissue-engaging element. In some implementations, the driver is further configured to push the pin through the series of holes, in a manner that inhibits unscrewing of the anchor from the tissue.

[0152] In accordance with some implementations, a method for use at a real or simulated tissue of a real or simulated subject includes advancing an anchor to the tissue, the anchor including (i) a head, and (ii) a helical tissue-engaging element extending from the head to define an anchor axis of the anchor. In some implementations, the method further includes screwing the helical tissue-engaging element along the anchor axis into the tissue. In some implementations, the method further includes locking the helical tissue-engaging element in the tissue by driving a second tissue-engaging element, engaged with the anchor, into the tissue non-colinearly with the anchor axis.

[0153] In some implementations, the second tissue-engaging element is a pin, and locking the tissue-engaging element in the tissue includes driving the pin, engaged with the anchor, into the tissue through a hole in the anchor eccentric to the anchor axis.

[0154] In some implementations, the anchor is a first anchor, and the helical tissueengaging element is a first helical tissue-engaging element. In some implementations, the second tissue-engaging element is a second helical tissue-engaging element of a second anchor. In some implementations, locking the first helical tissue-engaging element in the tissue includes driving the second helical tissue-engaging element into the tissue obliquely to the anchor axis in a manner that it engages with the first helical tissue-engaging element.

[0155] In some implementations, non-colinearly indicates an oblique angle to the anchor axis. In some implementations, non-colinearly indicates parallel and lateral to the anchor axis.

[0156] In accordance with some implementations, a method for use at a real or simulated tissue of a real or simulated subject includes advancing an anchor to the tissue, the anchor including (i) a head, and (ii) a helical tissue-engaging element extending from the head to define an anchor axis of the anchor. In some implementations, the method further includes screwing the helical tissue-engaging element along the anchor axis into the tissue. In some implementations, the method further includes locking the helical tissue-engaging element in the tissue by driving a second tissue-engaging element, engaged with the anchor, into the tissue non-colinearly with the anchor axis.

[0157] In some implementations, the method further includes sterilizing the anchor and the second-tissue-engaging element.

[0158] In some implementations, the second tissue-engaging element is a pin, and locking the tissue-engaging element in the tissue includes driving the pin, engaged with the anchor, into the tissue through a hole in the anchor eccentric to the anchor axis.

[0159] In some implementations, the anchor is a first anchor, and the helical tissueengaging element is a first helical tissue-engaging element. In some implementations, the second tissue-engaging element is a second helical tissue-engaging element of a second anchor. In some implementations, locking the first helical tissue-engaging element in the tissue includes driving the second helical tissue-engaging element into the tissue obliquely to the anchor axis in a manner that it engages with the first helical tissue-engaging element.

[0160] In some implementations, non-colinearly indicates an oblique angle to the anchor axis. In some implementations, non-colinearly indicates parallel and lateral to the anchor axis.

[0161] Any of the above method(s) and any methods of using the systems, assemblies, apparatuses, devices, etc. herein can be performed on a living subject (e.g., human, or other animal) or on a simulation (e.g., a cadaver, cadaver heart, imaginary person, simulator, etc.). With a simulation, the body parts can optionally be referred to as “simulated” (e.g., simulated heart, simulated tissue, etc.) and can optionally comprise computerized and/or physical representations.

[0162] Any of the above systems, assemblies, devices, apparatuses, components, etc. can be sterilized (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.) to ensure they are safe for use with subjects, and the methods herein can comprise (or additional methods comprise or consist of) sterilization of one or more systems, devices, apparatuses, components, etc. herein (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.).

[0163] The present disclosure will be more fully understood from the following detailed description of implementations thereof, taken together with the drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0164] Fig. 1 is a schematic illustration of a tissue anchor comprising a helical tissueengaging element having a tubular lumen and a shape-set wire passable therethrough;

[0165] Figs. 2A, 2B, 2C, and 2D are schematic illustrations showing a tissue anchor comprising a shape-set wire being deployed into a tissue, in accordance with some implementations ;

[0166] Figs. 3A, 3B, and 3C are schematic illustrations of a tissue anchor comprising a grip-body positioned between a head and a tissue-engaging element;

[0167] Figs. 4A, 4B, 5A, and 5B are schematic illustrations showing a tissue anchor comprising a grip-body being deployed into or out of a tissue, in accordance with some implementations ;

[0168] Figs. 6A and 6B are schematic illustrations of a tissue anchor comprising a head and a collar positioned off-center with respect to the tissue-engaging element;

[0169] Figs. 7A, 7B, 7C, 7D and 8 are schematic illustrations showing a series of tissue anchors with collars being deployed into a tissue, in accordance with some implementations;

[0170] Figs. 9A and 9B are schematic illustrations showing a tissue anchor having a stabilizer aligned with an eyelet of the anchor;

[0171] Figs. 10A, 10B, 10C, 11 A, 11B, and 11C are schematic illustrations showing a tissue anchor having different intra-helical distances being deployed into a tissue, in accordance with some implementations;

[0172] Figs. 12A, 12B, 12C, 13A, 13B, 14A, 14B, 15, 16A, 16B, 16C, 16D, 17A, 17B, and 17C are schematic illustrations showing a series of tissue anchors having compressible helices, in accordance with some implementations;

[0173] Figs. 18A, 18B, 18C, 19A, 19B, 19C, 20A, and 20B are schematic illustrations showing a tissue anchor with a foot and an external spring being deployed into a tissue, in accordance with some implementations;

[0174] Fig. 21 is a schematic illustration showing two interlocking tissue anchors being deployed by a delivery tool, in accordance with some implementations; and [0175] Figs. 22A, 22B, 22C, 23A, 23B, and 23C are schematic illustrations showing a series of tissue anchors with a stabilizing pin being deployed into a tissue, in accordance with some implementations.

DETAILED DESCRIPTION

[0176] The present disclosure includes different variants of some elements. Variants of a given element typically have the same structure and/or function as each other except for any differences described. For any given element for which different variants are disclosed, the identical name is used for each variant, in order to denote that they are, in fact, variants of the same given element. Unless stated otherwise, applications of the devices, systems, and techniques described herein may include any arrangement in which one variant of an element is substituted with another identically-named variant of that element. Furthermore, throughout the figures, suffixes are used to denote different variants of the same element. Unless stated otherwise, such variants may be substituted with each other, mutatis mutandis. That is, unless stated otherwise, any element having a given reference numeral may be substituted with any other element (i.e. any other variant of the element) having the same reference numeral, independent of any suffix.

[0177] In order to avoid undue clutter from having too many reference numbers and lead lines on a particular drawing, some elements are introduced via one or more drawings and not explicitly identified in every other drawing that contains that element.

[0178] Reference is now made to Figs. 1 and 2A-D, which are schematic illustrations of a system comprising a helical tissue anchor 10, in accordance with some implementations. The system may also comprise a driver 18 for transluminally advancing and anchoring anchor 10 into a tissue. Fig. 1 shows a tissue anchor 10, and Figs. 2A-D show a process of anchoring tissue anchor 10 into a tissue.

[0179] Anchor 10 comprises a head 16, and a tissue-engaging element 12. Tissue-engaging element 12 comprises a tubular helical member 13, and a wire 14. Head 16 may comprise an interface that is configured to be engaged by driver 18 in order to screw tissue-engaging element 12 (e.g., tubular helical member 13) into the tissue. Head 16 is fixed to tissueengaging element 12, which defines a longitudinal anchor axis of the anchor. In some implementations, the tissue-engaging element can comprise other arrangements, including, but not limited to barbs, spikes, tips, hooks, arrows, and the like and be driven into the tissue via the driver 18. [0180] Tissue-engaging element 12 comprises a tubular helical member 13 defining a helical lumen that runs along a length of the helical element - e.g., from head 16 toward a distal tip, e.g., helically along and around the longitudinal anchor axis. Tubular helical member 13 may comprise a metal having high mechanical strength and/or rigidity, such as titanium. Tubular helical member 12 is configured to allow passage of wire 14 through the helical lumen.

[0181] Wire 14 is configured to be passed through the helical lumen of tubular helical member 13. In some implementations, and as shown, wire 14 may pass through head 16 along the longitudinal anchor axis. In some implementations, wire 14 is configured to exit the helical lumen at the distal tip of tissue-engaging element 12. In some implementations, tissue-engaging element 12 (e.g., tubular helical member 13) defines a lateral opening from the helical lumen (e.g., proximal from the distal tip), and wire 14 is configured to exit the helical lumen via the lateral opening.

[0182] Wire 14 comprises a shape-set material, such as nitinol. A proximal end of wire 14 may define a stop 15, configured to prevent the proximal end of wire 14 from passing beyond a proximal opening of the tubular member into the helical lumen. At least a distal end of wire 14 (i.e., a shape-set end) may be pre-shaped with a set shape such that it is with a bias to curve in a direction different from that of a directionality of tubular helical member 13 through which wire 14 passes. Prior to deployment of anchor 10 into a tissue, wire 14 may be constrained within the helical lumen of tubular helical member 13.

[0183] The set shape of wire 14 may differ in various implementations. The set shape may be designed based on, e.g., retention strength and anatomical features of the tissue into which anchor 10 will be anchored. In some implementations, the set shape may have a greater curvature than that of the helical lumen. In some implementations, the set shape may have a lesser curvature than that of the helical lumen. In some implementations, wire 14 may have a shape-set bias opposite to that of a handedness of tissue-engaging element 12. In any implementation, wire 14 is shaped to advantageously inhibit undesired (e.g., passive) unscrewing of anchor 10 during the constant movement of heart tissue into which anchor 10 may be anchored.

[0184] In Figs. 2A-D, anchor 10 is shown being anchored into a tissue 8. Fig. 2A shows driver 18 engaged with head 16 (e.g., with an interface thereof), to which the driver applies torque to screw tubular helical member 13 into tissue 8. In the example shown, tubular helical member 13 is right-handed and is screwed clockwise into tissue 8. Fig. 2B shows tubular helical member 13 having been fully screwed into the tissue - e.g., to an extent that a distal aspect of head 16 contacts the surface of tissue 8. At this point, driver 18 (e.g., a rod 17 thereof) is used to push wire 14 distally through the helical lumen such that the shape-set end of the wire becomes exposed out of tubular helical member 13 - e.g., out of the distal tip (Fig. 2C). In some implementations, and as shown, rod 17 pushes wire 14 through a lumen in head 16. As it becomes exposed from the helical lumen, the shape-set end of wire 14 assumes its set shape. Driver 18 can then be disengaged from head 16 and removed, leaving anchor 10 engaged with tissue 8 (Fig. 2D).

[0185] In some implementations, and as shown, the set shape of the shape-set end of wire 14 is such that it projects in a direction different from that of tubular helical member 13. The extension of wire 14 out of tubular helical member 13 in a direction different from the screw direction produces an out-of-axis force that would need to be overcome if the anchor is to unscrew. As the protruding wire is biased toward a handedness or directionality different from that of the tissue-engaging element, a greater force would be required to counteract the out-of-axis forces created by the different orientation of the wire. Thus, the difference in directionality between wire 14 and tubular helical member 13 advantageously inhibits potential unscrewing of the anchor.

[0186] In some implementations, a proximal end of wire 14 may have a wider outer diameter than the rest of the wire, i.e., wider than an inner diameter of the helical lumen. In some implementations, head 16 may comprise a notch (not shown) configured to accept a proximal end of wire 14. The wider proximal end of the wire may be shaped to fit into the notch. Such a notch may ensure that wire 14 neither is released proximally nor penetrates into the tissue too deeply.

[0187] Reference is made to Figs. 3A-C, 4A-B, and 5A-B, which are schematic illustrations of a system comprising a tissue anchor having a helical tissue-engaging element and a supplementary grip-body, in accordance with some implementations. The system may also comprise a driver for transluminally advancing and anchoring the anchor into a tissue. Figs. 3A-C show components of a tissue anchor 20; Figs. 4A-B show anchor 20 being advanced into a tissue 8; and Figs. 5A-B show a process of unscrewing anchor 20 out of the tissue.

[0188] As shown in Figs. 3A-C, anchor 20 comprises a head, comprising a base 26 and a grip-body 24, and a tissue-engaging element 22. [0189] In some implementations, the anchor head comprises a base 26 that comprises an interface 21, a neck 25, and a plate 19. Interface 21 is configured to be engaged by a driver in order to screw tissue-engaging element 22, e.g., a helical tissue-engaging element, into the tissue. In some implementations, the tissue-engaging element can comprise other arrangements, including, but not limited to barbs, spikes, tips, hooks, arrows, and the like. A distal aspect of base 26 comprises multiple petals 120 defined by a plate 19. Plate 19, i.e., petals 120 thereof, are configured to contact the surface of a tissue as anchor 20 is screwed into the tissue. In some implementations, petals 120 have a directionality that is compatible with a directionality of helical tissue-engaging element 22, i.e., the petals do not interfere with screwing helical tissue-engaging element 22 into the tissue. In some implementations, and as shown, the petals lack a specific directionality, i.e., they extend laterally from a longitudinal axis of the anchor without having a bias in a specific direction. Neck 25 is disposed between, and fixedly coupled to, interface 21 and plate 19. In some implementations, a bushing (unlabeled in Fig. 3A) may be rotatably disposed around the neck 25.

[0190] A further component of the anchor head is grip-body 24, rotatably disposed around neck 25, e.g., below the bushing and/or above plate 19. Grip-body 24 comprises multiple, e.g., two, three, four, or five, grip-body lobes 122, each grip-body lobe comprising a sharp grip 23, e.g., a grip edge, acting as a friction feature. Each grip-body lobel22 extends away from the longitudinal anchor axis in a manner that grip 23 defines a directionality of gripbody lobel22. Each grip-body lobel22 is associated with a respective petal 120, and is sized and shaped such that grip-body lobel22 may be positioned above its associated petal 120 in a manner that grip 23 extends beyond a perimeter of the petal. Grip-body lobe 122 may also be positioned above its associated petal 120 in a manner that grip 23 is obscured by a perimeter of petal 120, as further detailed herein below. In some implementations, the directionality of grip-body lobes 122 is opposite to that of a handedness of helical tissueengaging element 22, e.g., grip-body lobes 122 may have a grip-directionality opposite that of the tissue-engaging element 22, such that, once screwed into the tissue, grip-body 24 impedes unscrewing of anchor 20.

[0191] In some implementations, base 26, e.g., plate 19, optionally comprises one or more, e.g., two, three, four, or five, stops 29. In some implementations, stops 29 are elevations or protrusions that extend above the surface of plate 19, i.e., toward interface 21. Stops 29 are configured to limit the rotation of grip-body 24, e.g., in a direction opposite to that of tissue- engaging element 22 as it is being unscrewed from the tissue. In some implementations, the base is configured with a stop 29 for each petal 120.

[0192] In some implementations, grip-body 24 and at least one of petals 120 collectively define a coupling that comprises a protrusion and an indentation on mutually-facing surfaces of the head. In some implementations, and as shown, base 26, e.g., plate 19, comprises a set of indentations 28, e.g., one, two, or three indentations on each petal. Grip-body 24 comprises a complementary set of protrusions 27 that mirror the set of indentations 28. When grip-body 24 rests on plate 19, protrusions 27 are configured to fit within indentations 28 in a manner that each grip 23 extends beyond its respective petal 120. Alternately, in some implementations, indentations 28 may be disposed on grip-body 24 and protrusions 27 may be disposed on plate 19.

[0193] Whereas grip-body 24 may be freely rotatable around neck 25, in practice, gripbody 24 has two stable positions with respect to base 26, e.g., with respect to plate 19. In other words, the anchor head may exist in two energetically favorable states. In a stable first state, protrusions 27 engage indentations 28 and edges 23 extend beyond the edge of plate 19. This is the position of grip-body 24 during deployment of anchor 20 and once helical tissue-engaging element 22 is fully engaged with a tissue, in some implementations. In a second stable state, protrusions 27 are disengaged from indentations 28 and grip-body 24 rotates until a surface of each grip, e.g., a surface opposite grip 23, contacts a respective stop 29. This second state may exist when anchor 20 is being unscrewed from the tissue, as described further herein below.

[0194] Tissue-engaging element 22 comprises a proximal end and a distal tip, and defines the longitudinal anchor axis of the anchor. In some implementations, and as shown, tissueengaging element 22 is a helical tissue-engaging element. Base 26 is fixed to helical tissueengaging element 22 in a manner that, in the first stable state, i.e., with protrusions 27 and indentations 28 engaged, applying torque to interface 21 is configured to rotate both base 26 and helical tissue-engaging element 22 as a single unit.

[0195] In Figs. 4A-B, anchor 10 is shown being advanced, i.e., screwed, into a tissue 8. In each figure, the upper image shows a top view of anchor 20 as it would appear from above the tissue, and the lower image shows a side view of anchor 20 as it would appear as it is being advanced into a tissue 8. Fig. 4A shows a position of grip-body 24 with respect to base 26 as both elements would appear when protrusions 27 are fitted within indentations 28 (not visible in this view). In this position, edge 23 is exposed above plate 19, e.g., extends beyond the petals thereof, as the anchor is being screwed into the tissue. As plate 19 is lowered against a surface of tissue 8, grips 23 of grip-body 24 come into contact with tissue 8. Thus, as shown in Fig. 4B, when helical tissue-engaging element 22 is fully deployed into tissue 8, edges 23 contact the surface of tissue 8 as lateral edges of plate 19 dip below the surface. In a deployed position of the anchor, protrusions 27 of grip-body 24 remain fitted within indentations 28 of plate 19, and grips 23 remain exposed above plate 19. The directionality and sharpness of edges 23 contribute to unscrewing of anchor 20.

[0196] In Figs. 5A-B, anchor 20 is shown being unscrewed from tissue 8, e.g., for intentional repositioning. In each figure, the upper image shows a top view of anchor 20 as it would appear from above the tissue, and the lower image shows a side view of anchor 20 as it would appear as it is being unscrewed from tissue 8. As reverse torque is applied to interface 21 to reverse tissue-engaging element 22 out of tissue 8, frictional force on gripbody 24 by tissue 8 causes protrusions 27 to become disengaged from indentations 28. Responsive to the application of reverse torque, anchor 20 thus transitions out of the first stable state and toward the second stable state. The friction causes grip-body 24 to rotate relative to base 26 in a direction opposite to the desired direction of unscrewing. Rotation of grip-body 24 stops when at least one grip-body lobel22 comes into contact with a stop 29 that prevents its further rotation. When grip-body lobe 122 contacts stop 29, the anchor head reaches the second stable state. In this second stable position, grips 23 are concealed by a profile of petals of plate 19, such that grips 23 are isolated from contact with tissue 8. Were grip-body 24 to remain in the position shown in Figs. 4A-B during the process of unscrewing, grips 23 could cause twist-damage to tissue 8.

[0197] In summary, when anchor 20 is deployed into tissue 8, plate 19 and grip-body 24 serve as a retention feature by advantageously contributing to stability of the anchor and inhibiting a tendency of the anchor to become accidentally dislodged. When anchor 20 is intentionally unscrewed, the petals of plate 19 conceal grips 23 of grip-body 24, thus minimizing twisting damage to tissue 8 from grip-body 24.

[0198] Reference is made to Figs. 6A-8, which are schematic illustrations of a system comprising a tissue anchor having a helical tissue-engaging element and a separately rotatable collar, in accordance with some applications. The system may also comprise a driver for transluminally advancing and anchoring the anchor into a tissue, and/or a wire to connect multiple anchors. Figs. 6A-B show an anchor 30, e.g., a variant 30a, comprising a head 36, a collar 34, e.g., variant 34a, and a helical tissue-engaging element 22. Fig. 7A shows an anchor 30b comprising a head 36, a collar 34b, and a helical tissue-engaging element 22. Figs. 7B-D show a process of a driver extending over the anchor head and collar.

[0199] Figs. 6A-B show anchor 30, 30a which comprises a head 36, a tissue-engaging element 32, and a collar 34 (e.g., variants 34a, 34b). Head 36 comprises an interface 31 for engaging a driver. In some implementations, and as shown, tissue-engaging element 32 is helical. In some implementations, the tissue-engaging element can comprise other arrangements, including, but not limited to barbs, spikes, tips, hooks, arrows, and the like. Helical tissue-engaging element 32 has a proximal end and a distal tip, and defines a longitudinal axis of the anchor. The proximal end may comprise a shaft. Head 36 is fixedly coupled to the proximal end of tissue-engaging element 32, e.g., to the shaft, via a coupling that is eccentric with respect to the head. In some implementations, interface 31 comprises a central slot via which the driver is configured to apply torque to head 36 to drive anchor 30 into a tissue. In some implementations, head 36 comprises a recess within which collar 34 is configured to rotate.

[0200] In some implementations, collar 34 is disposed between head 36 and the proximal end of the tissue-engaging element. In some implementations, collar 34 may be considered part of a head assembly. Collar 34 may be rotatably coupled to tissue-engaging element 32 by the proximal end, e.g., the shaft, extending through collar 34 in a manner that collar 34 is configured to rotate freely around the shaft as anchor 30 is screwed into a tissue. The shaft may be eccentric with respect to collar 34, and/or collar 34 may be eccentric with respect to the anchor axis. Collar 34 comprises an eyelet 35, disposed laterally, e.g., perpendicular, with respect to a longitudinal axis of anchor 30.

[0201] As shown in Fig. 6B, two views are shown for each of two states of anchor 30 as the head 36 and tissue-engaging element 32 are rotated by application of torque to interface 31. The upper image shows a top view of anchor 30 as it would appear from above the tissue, and the lower image shows a side view of anchor 30 as it would appear as it is being advanced into a tissue. A tether 33 may be threaded through eyelet 35 of collar 34 (e.g., variant 34a). As torque is applied to interface 31 to screw anchor 30 longitudinally into a tissue, head 36 and helical tissue-engaging element 32 are rotated as a unit along the longitudinal anchor axis into the tissue. At the same time, lateral tension may be applied to tether 33. The lateral tension maintains eyelet 35 of collar 34 in a fixed orientation with respect to the anchor axis, e.g., directed toward the applied tension. [0202] As shown in Fig. 6B, an axis of collar 34 has an eccentricity with respect to the anchor axis, such that as the driver applies torque to interface 31, collar 34 revolves independently around the anchor axis. During each rotation of the head and the tissueengaging element, collar 34 exhibits reciprocating motion by periodically extending eccentrically beyond a circumference of head 36, as shown in the right half of Fig. 6B. The independent rotation of collar 34, e.g., while anchor 30, i.e., tissue-engaging element 32, is being rotated into a tissue may advantageously prevent tether 33 from becoming wrapped around anchor 30. This advantage is particularly relevant when a series of anchors, e.g., connected by a single tether 33, are being screwed into a tissue, e.g., a valve of a heart.

[0203] Pulling on tether 33 threaded through two or more eyelets 35 causes collar 34 to swivel with respect to head 36, e.g., away from the longitudinal anchor axis. Causing collar 34 to swivel with respect to head 36 is advantageously configured to minimize a pull-out force on tissue-engaging element 32 by tether 33.

[0204] Fig. 7A shows a variant 34b of the collar comprising a beveled proximal surface. In some implementations, and as shown, eyelet 35 is disposed through the beveled aspect of collar 34b. The expanded view of Fig. 7A shows collar 34b from top, bottom, front, and side views, to illustrate the design of the collar. In some implementations, and as shown, the collar axis rotates around opening 37 at an unbeveled aspect of the collar. Opening 37 is situated essentially perpendicular to eyelet 35, which extends laterally through the bevel.

[0205] Figs. 7B-D illustrate an advantageous implementation of the beveled collar. As shown in Fig. 7B, driver 39 has engaged head 36, and advanced anchor 30 out of catheter 38 and into a tissue. Collar 34b is shown extending beyond the circumference of head 36, as shown also for collar 34a in Fig. 6B. In the event that anchor 30 needs to be repositioned, e.g., as shown in Fig. 7C, catheter 38 is lowered toward a surface of the tissue in order to resheath head 36. Catheter 38 has a diameter minimally greater than the diameter of head 36. Because collar 34b extends beyond the circumference of head 36, collar 34b must rotate under head 36 in order for head 36 to be fully re-sheathable within catheter 38. As shown in Fig. 7D, the beveled proximal surface of collar 34b facilitates re-sheathing: as catheter 38 is lowered and touches the extended collar, the beveled surface enables collar 34b to responsively rotate into colinear alignment with the head 36 and tissue-engaging element 32 as the collar is drawn into the catheter.

[0206] Fig. 8 illustrates a valve of a heart, e.g., a mitral valve, surrounding which a series of anchors 30 has been implanted. Tether 33 has been threaded through the respective collar 34 (34a, 34b) of each anchor 30. Pulling on a distal, e.g., free, end of tether 33 draws anchors 30 toward each other around the valve, thus facilitating, e.g., a reduction of regurgitation at the valve. Applying tension to tether 33 is done in a manner that draws the anchors, e.g., via tether 33 passing through eyelet 35 of collar 34, medially with respect to a curve, e.g., an arc, defined by the tether in response to anchoring anchors 30 around the valve. As shown in the inset, after tensioning the tether, the collar of each anchor is oriented toward the central point of the curve. Anchors 30 having an offset collar 34 can advantageously prevent unwinding (pull-out) from the tissue. This advantage is most prominent when two or more anchors are tethered in series, e.g., with a tether, as shown in Fig. 8. Although illustrated with respect to the mitral valve, a skilled artisan will appreciate that implementations of the present disclosure may be used with other valves, such as the tricuspid valve.

[0207] Reference is now made to Figs. 9A-22C, which are schematic illustrations of various systems and methods of anchoring anchors into tissue. While each figure illustrates a respective concept, it is to be understood that individual elements of each system are interchangeable within and between the other systems, resulting in combinations that are not specifically shown.

[0208] Throughout the present application, the term "diameter" with respect to a helical tissue-engaging element is defined as a width of the helix defined by the tissue-engaging element. As distinct from the diameter, the term "thickness" of the tissue-engaging element relates to the cross-sectional thickness (e.g. the outer diameter) of a material (e.g. a wire or tube), such as that which is shaped to form the helix of the helical tissue-engaging element.

[0209] Reference is now made to Figs. 9A-B, which are schematic illustrations of a system comprising a stabilized helical tissue anchor 130, in accordance with some implementations. The system may also comprise a delivery tool 138 for transluminally advancing and anchoring anchor 130 into a tissue 8. Fig. 9A shows a process of anchoring tissue anchor 130 into tissue 8, and Fig. 9B shows tissue anchor 130 fully deployed in a stabilized position within the tissue. In each of Figs. 9A-B, the top drawing shows anchor 130 as viewed from above, and the lower drawing shows anchor 130 as viewed from the side.

[0210] Anchor 130 comprises a head 136 and a helical tissue-engaging element 132. Head 136 may comprise an eyelet 133, through which a tether (such as tether 33, described elsewhere herein) may be threaded. In some implementations, anchor 130 comprises a stabilizer 134 having a first endl31 that is fixedly coupled to head 136 at a distal aspect of the head, and a free end 135. As shown, stabilizer 134 may curve around (e.g. may extend in a circular direction) at least partway around head 136.

[0211] Stabilizer 134 can be defined by a resilient wire. In the delivery state of anchor 130 (Fig. 9A), stabilizer 134 (e.g. its wire) can extend at least 180 degrees and/or less than 360 degrees around the head. In its deployed state (Fig. 9A) stabilizer 134 may extend around the head to a lesser extent, e.g., at least 180 degrees (e.g. at least 220 degrees) and/or less than 300 degrees (e.g. less than 280 degrees).

[0212] As shown in Fig. 9A, while delivery tool 138 delivers anchor 130 to tissue 8, stabilizer 134 is constrained around head 136 within delivery tool 138. Stabilizer 134 may be biased such that, responsively to deployment from delivery tool 138, the stabilizer deflects laterally from head 136 (Fig. 9B), e.g., unwrapping at least partially from a coiled position in which it was disposed within the delivery tool. In the deployed state, stabilizer 134 extends beyond a lateral extent of tissue-engaging element 132 and eyelet 133.

[0213] In some implementations, the fixed coupling of first end 131 to head 136 rotatably fixes stabilizer 134 with respect to eyelet 133, such that stabilizer 134 is circumferentially oriented with respect to eyelet 133. In the example shown, stabilizer 134 is circumferentially oriented with respect to eyelet 133 such that the maximal lateral protrusion (i.e. lateral extent) of stabilizer 134 from head 136 is at the rotational orientation of eyelet 133.

[0214] Stabilizer 134 can be substantially planar in its deployed state such that it rests upon a surface of tissue 8. In some implementations, the deflection of the stabilizer during deployment is in this plane.

[0215] In some implementations, anchor 130 is anchored into tissue as part of a series of anchors, each of which is coupled via a tether threaded through eyelet 133, e.g., as shown in Fig. 8. Such a tether would exert a lateral force on eyelet 133 in a manner that would bias anchor 130 to tilt in the direction of the exerted force. Stabilizer 134 is configured to advantageously inhibit tilting of anchor 130 in a direction in which the tether, e.g., connecting multiple anchors, would exert the force.

[0216] Reference is made to Figs. 10A-C and 11A-C, which are schematic illustrations of respective tissue anchors 40 and 50, and systems comprising these tissue anchors, in accordance with some implementations. Each of tissue anchors 40 and 50 comprises a helical tissue-engaging element that is screwable into the tissue, and which has (i) at a distal end of the tissue-engaging element, a distal pair of adjacent helical turns of the series that has a first inter-turn gap therebetween, and (ii) proximal from the distal pair, a proximal pair of adjacent helical turns of the series that has a second inter-turn gap therebetween, the second inter-turn gap being smaller than the first inter-turn gap.

[0217] As these tissue-engaging elements are progressively screwed into the tissue, a first amount of screwing in captures a part of the tissue in the distal inter-turn gap, and further screwing-in squeezes the part of the tissue into the second inter-tum gap, thereby gripping the tissue and/or enhancing anchoring of the anchor. As described in more detail hereinbelow, the differential sizing of these inter-turn gaps is achieved in anchor 40 by differential thickness of the tissue-engaging element, whereas it is achieved in anchor 50 by differential pitch of the tissue-engaging element.

[0218] Reference is now made to Figs. 10A-C, which are schematic illustrations of a system comprising a tissue anchor 40, in accordance with some implementations. The system may also comprise a driver for transluminally advancing and anchoring anchor 40 into a tissue 8. Fig. 10A shows a tissue anchor 40, and Figs. 10B-C show a process of anchoring tissue anchor 40 into tissue 8.

[0219] Anchor 40 comprises a head 46 defining an interface 47 that is engageable by a driver. Head 46 may comprise a base 460. Head 46 is fixedly coupled to a helical tissueengaging element 42. Helical tissue-engaging element 42 extends distally away from the head, e.g., from base 460, toward a distal tip of the helical tissue-engaging element. Helical tissue-engaging element 42 extends in a series of helical turns in a manner that defines an anchor axis AA along which the tissue-engaging element is screwable into tissue 8.

[0220] A distal pair of adjacent helical turns 45, disposed toward (e.g. at) a distal end of tissue-engaging element 42, defines a first inter-turn gap d2. Proximal from the distal pair, a proximal pair of adjacent helical turns 43 defines a second inter-tum gap dl that is smaller than inter-tum gap d2.

[0221] For anchor 40, inter-tum gap dl is smaller than inter-tum gap d2 due to differential thickness of the tissue-engaging element. Tissue-engaging element 42 has a thickness tl at proximal pair of adjacent helical turns 43 that is greater than its thickness t2 at distal pair of adjacent helical turns 45. Despite the differential thickness of tissue-engaging element 42, the tissue-engaging element may have a constant pitch and/or a constant diameter along the series of helical turns. [0222] As shown in Figs. 10B-C, anchor 40 is configured to be screwed into tissue 8 by a driver (not shown). The driver is configured, via engagement with interface 47, to screw tissue-engaging element 42 into tissue 8 such that a first amount of screwing of tissueengaging element 42 into tissue 8 captures a part 9 of the tissue between distal adjacent helical turns 45 having inter-tum gap d2.

[0223] In some implementations, further screwing of tissue-engaging element 42 into tissue 8 places (e.g. squeezes) part 9 of the tissue between proximal adjacent helical turns 43 having inter-tum gap dl. Consequently, part 9 of the tissue becomes compressed between proximal pair of adjacent helical turns 43. As noted above, this may advantageously create greater holding force of the tissue-engaging element within tissue 8, inhibiting unwinding of anchor 40 after implantation.

[0224] Reference is now made to Figs. 11A-C, which are schematic illustrations of a system comprising a helical tissue anchor 50, in accordance with some implementations. The system may also comprise a driver for transluminally advancing and anchoring anchor 50 into a tissue 8. Fig. 11A shows a tissue anchor 50, and Figs. 11B-C show a process of anchoring tissue anchor 50 into tissue 8.

[0225] Anchor 50 comprises a head 56 defining an interface 57 that is engageable by a driver (not shown). Head 56 may be fixedly coupled to a helical tissue-engaging element 52 at a base 460. Helical tissue-engaging element 52 has a proximal end extending distally away from head 56, e.g., from base 460, toward a distal tip, in a series of helical turns. In some implementations, the helical turns define an anchor axis AA along which tissue-engaging element 52 is screwable into the tissue.

[0226] In some implementations, a first pair of adjacent helical turns 53 of the series has a first pitch pl, and distal from the first pair, a second pair of adjacent helical turns 55 of the series has a second pitch p2, the second pitch being greater than the first. In some implementations, first pitch pl may be greater than 0.8 mm and/or less than 1.1 mm (e.g. approximately 0.90 mm), and second pitch p2 may be greater than 1.1 mm and/or less than 1.4 mm (e.g. approximately 1.20 mm).

[0227] Despite the differential pitch of tissue-engaging element 52, the tissue-engaging element may have a constant diameter and/or a constant thickness along the series of helical turns. [0228] As shown in Figs. 11B-C, and as described herein above with regard to Figs. 10B- C, in some implementations, as tissue-engaging element 52 is screwed into tissue 8 by engagement of the driver with interface 57, such that a first amount of screwing of tissueengaging element 52 into tissue 8 captures a part 9 of the tissue in between distal adjacent helical turns 55 having a pitch p2 and an inter-turn gap d4. Further screwing of tissueengaging element 52 into tissue 8 places (e.g. squeezes) part 9 of the tissue between proximal adjacent helical turns 53 having a pitch pl and an inter-turn gap d3. Consequently, part 9 of the tissue becomes compressed between proximal pair of adjacent helical turns 53. As noted above, this may advantageously create greater holding force of the tissue-engaging element within tissue 8, inhibiting unwinding of anchor 40 after implantation.

[0229] Reference is again made to Figs. 10A-11C. In some implementations, the series of helical turns of tissue-engaging element 42 and/or 52 includes, proximal from proximal pair of adjacent helical turns 43 and/or 53, another pair of adjacent helical turns of the series. The other pair of adjacent helical turns may have another inter-tum gap therebetween, e.g., interturn gap 41 shown in Figs. 10A-C, inter-turn gap 41 being greater than that of the proximal pair of adjacent helical turns 43.

[0230] Although the adjacent helical turns 43 that define inter-tum gap dl are shown as being located in a midsection of the series of helical turns, it is to be understood that they may alternatively be located further toward (e.g. at) a proximal end of the series of helical turns, e.g., as shown for adjacent helical turns 53 of anchor 50.

[0231] For each of Figs. 10A and 11A, although only one inter-tum gap dl, d2, d3, and d4 is specifically labeled as such, it is to be noted that more than one pair of adjacent helical turns may have an inter-tum gap of the size of inter-turn gap dl, d2, d3, and/or d4. Inter-tum gap dl may be smaller than inter-tum gap d2, and/or inter-tum gap d3 may be smaller than inter-turn gap d4 by a respective distance, e.g., 0.5 mm, 1 mm, 1.5 mm, or 2 mm. In some implementations, second inter-tum gap dl may be smaller than the first inter-tum gap by a respective percentage, e.g., 10%, 20%, 30%, 40%, or 50%.

[0232] It is to be understood that tissue-engaging element 42 may have a progressive change in thickness, e.g., from tl to t2, along a length of the tissue-engaging element, e.g., from proximal end to distal tip. Tissue-engaging element 52 may have a progressive change in pitch, e.g., from pl to p2, along a length of the tissue-engaging element, e.g., from proximal end to distal tip. In some implementations, the tissue-engaging element may have a combination of changes in pitch and thickness. [0233] Reference is now made to Figs. 12A-C, 13A-B, 14A-B, 15, and 16A-D, which are schematic illustrations of systems comprising a helical tissue anchor, in accordance with some implementations. In some implementations, the tissue anchor of each system comprises a helical tissue-engaging element extending helically away from a head.

[0234] In some implementations, the system may also comprise a driver for transluminally advancing and anchoring anchor 60 or 70 into a tissue. In some implementations, the tissueengaging element of each anchor defines a helical channel therealong, and a wire extends along the helical channel.

[0235] In some implementations, via engagement with the head, a driver is configured to anchor the anchor to the tissue by (i) screwing the tissue-engaging element into the tissue, and (ii) subsequently, reducing the pitch of the helical tissue-engaging element using (e.g. by pulling) the wire, thereby squeezing/gripping the tissue between helical turns of the tissue-engaging element.

[0236] Figs. 12A-C show a system 69 in which pulling on the wire reduces the pitch of the helical tissue-engaging element by plastically deforming the tissue-engaging element. Figs. 13A-16D show variants of a system 179 in which the wire constrains the tissue-engaging element, and in which pulling on the wire removes the wire from the helical lumen thereby allowing the tissue-engaging element to elastically contract (e.g. to relax).

[0237] Each of Figs. 12A-C, 13A-B, 14A-B, and 15-16D illustrate a different example mechanism for accomplishing a squeezing or compression of the tissue-engaging element within the tissue. Fig. 12A shows a tissue anchor 60, and Figs. 12B-C show a process of anchoring tissue anchor 60 into tissue 8. Figs. 13A-B, 14A-B, and 15 show a system 179 (e.g., variants 179a, 179b, 179c thereof) comprising tissue anchor 70 (e.g., variants 70a, 70b, 70c thereof). Figs. 13A-B show system 179a comprising an anchor 70a. Figs. 14A-B show system 179b comprising an anchor 70b. Fig. 15 shows system 179c comprising an anchor 70c, and Figs. 16A-D show a process of anchoring any of anchors 70a, 70b, and/or 70c into tissue 8.

[0238] Reference is now made to Figs. 12A-C, which are schematic illustrations of a system 69 comprising a tissue anchor 60 and, optionally, a driver (not shown). Anchor 60 comprises a head 66 having an interface 67. A tissue-engaging element 62 extends helically away from head 66, defining a helical lumen 61 therealong, tissue-engaging element 62 defining a first pitch. Tissue-engaging element 62 comprises a plastically-deformable material, e.g., cobalt-chrome or a stainless steel. A wire 63 extends along the helical lumen toward a distal tip 65 of the tissue-engaging element.

[0239] As shown in Fig. 12B, via engagement with interface 67 of head 66, the driver is configured to anchor anchor 60 to tissue 8 by screwing tissue-engaging element 62 into the tissue. At this point, tissue-engaging element 62 has a length of L0. As shown in Fig. 12C, system 69, e.g. the driver or another component thereof, is configured to subsequently apply tension to wire 63, plastically deforming tissue-engaging element 62 to have a reduced pitch, as reflected by compressed length LI.

[0240] Wire 63 may be permanently or temporarily attached to distal tip 65 of tissueengaging element 62. In some implementations, wire 63 can be a component of anchor 60.

[0241] In some implementations, tension applied to wire 63 shortens a length of the wire remaining within the helical lumen 61. System 69 (e.g. anchor 60 and/or wire 63) may comprise or define a ratchet mechanism or a lock (not shown), that will prevent slippage of wire 63 back into the helical lumen. Tissue-engaging element 62 remains in its compressed state, i.e., with the reduced pitch.

[0242] In some implementations, wire 63 may be configured to detach from distal tip 65 of tissue-engaging element 62 after tension has been applied to wire 63 by system 69. For example, wire 63 may be anchored at distal tip 65 using a snap-fit mechanism that maintains a predetermined load before disengaging. Wire 63 may be designed to break after a certain tensile load is applied, e.g. by using a wire with a smaller outer diameter at a point, or a notch cut at a point.

[0243] In such cases, tissue-engaging element 62 remains with a reduced pitch due to its plastically deformable properties.

[0244] Reference is now made to Figs. 13A-16D, which are schematic illustrations of variants of a system 179 comprising variants of a tissue anchor 70, and a driver. In some implementations, anchor 70 comprises a head 76 having an interface 77, and a helical tissueengaging element. In some implementations, the tissue-engaging element defines a helical channel therealong, and is biased toward having a reduced pitch, and thereby a reduced length LI.

[0245] In some implementations, a wire extends helically along the helical channel in a manner that constrains the helical tissue-engaging element to have an increased pitch and thereby an increased length L0. In some implementations, the wire or inner helical coil has a stiffness or spring constant greater than that of the tissue-engaging element. In some implementations, the tissue-engaging element is configured to be screwed into the tissue by engagement of a driver (not shown) with the interface.

[0246] Figs. 13A-B show an anchor 70a that comprises a head 76 having an interface 77. A tissue-engaging element 72 extends helically away from head 76, defining a helical channel 71, e.g., a lumen 71a, therealong. In some implementations, tissue-engaging element 72 comprises an elastically-deformable material and is biased toward having a reduced pitch, and thereby a reduced length LI.

[0247] In some implementations, wire 73 extends along lumen 71a. In some implementations, wire 73 is shaped to have a series of coils having an increased pitch greater than the first pitch, and thereby an increased length L0. In some implementations, the series of coils has a stiffness greater than a stiffness of tissue-engaging element 72, such that, when extended along the helical channel, e.g., before anchoring into a tissue, wire 73 constrains the helical tissue-engaging element to have the increased pitch (Fig. 13 A).

[0248] In some implementations, via engagement with interface 77 of head 76, a driver is configured to anchor anchor 70a into a tissue by screwing tissue-engaging element 72 into the tissue. Subsequent removal of wire 73 enables tissue-engaging element 72 to relax into the reduced pitch within the tissue (Fig. 13B).

[0249] Referring again to Figs. 12A-C and 13A-B, it is to be noted that the mechanism shown in Figs. 13A-B differs from that shown in Figs. 12A-C in that tissue-engaging element 62 has an initial length L0 that is plastically deformable to length LI, whereas tissueengaging element 72 has an initial length LI that is constrained to length L0, and relaxes to length LI upon removal of the wire. Wire 63 may not have a pre-formed shape, in contrast to wire 73, which is shaped to have a series of coils.

[0250] Figs. 14A-B show an anchor 70b that comprises a head 76 having an interface 77. In some implementations, a tissue-engaging element 74 extends helically away from head 76, defining a helical channel 71b comprising a groove running along an inner face of tissueengaging element 74. In some implementations, the groove may have a U-shaped or a C- shaped cross-sectional area. In some implementations, the outer coil of tissue-engaging element 74 comprises a shape-set material defining a compressed set shape.

[0251] In some implementations, a wire 79 defines a stiff inner coil running within helical channel 71b of the outer coil defined by the tissue-engaging element 74. In some implementations, wire 79 comprises coils of a shape-set material defining an extended set shape, e.g., the coil has an increased pitch (Fig. 14A).

[0252] In some implementations, when extended through the helical channel, wire 79 maintains tissue-engaging element 74 in the extended set shape. In some implementations, via engagement with interface 77 of head 76, a driver is configured to anchor anchor 70b into a tissue by screwing tissue-engaging element 74 into the tissue. In some implementations, pulling or unscrewing wire 79 out of the helical channel allows the outer coils of the tissue-engaging element to relax and assume the compressed shape set within the tissue. Thus, a reduced pitch is restored to tissue-engaging element 74 by extracting wire 79 from the helical channel (Fig. 14B).

[0253] Figs. 15 and 16A-D are schematic illustrations of a system 179 (e.g., variants 179b, 179c) comprising a driver 81 and a helical tissue anchor 70 (e.g., variants 70b, 70c). It is to be understood that individual elements of system 179, e.g., driver 81 or components thereof, may be interchangeably used within and between other systems resulting in combinations that are not specifically shown. For example, system 179b in Figs. 14A-B, e.g., tissueengaging element 74 and wire 79 of anchor 70c, may be adapted for use with driver 81. Thus, the following description may refer to either or both systems.

[0254] In some implementations, anchor 70c comprises a head 76 having an interface 77. In some implementations, tissue-engaging element 72 extends helically away from head 76 and defines a helical channel or lumen 71a therealong. In some implementations, running through helical lumen 71a, a wire 75 defines a stiff inner coil within an outer coil defined by tissue-engaging element 72. In some implementations, wire 75 is configured to stiffen or lengthen tissue-engaging element 72 prior to and/or upon deployment into tissue 8.

[0255] In some implementations, the outer coil comprises an elastically deformable hollow tube comprising a shape-set material, e.g., nitinol. In some implementations, the outer coil has a shape-set pitch smaller than that of wire 75, e.g., of the inner coil thereof. In some implementations, the outer coil has a memory shape corresponding to length LI. In some implementations, the helical lumen 71 of tissue-engaging element 72 may have a circular cross-sectional area.

[0256] In some implementations, the inner coil of wire 75 comprises a stiff material such as stainless steel, and has a spring constant greater than that of the outer coil of tissueengaging element 72. [0257] In some implementations, when the inner coil is threaded through the helical lumen of the outer coil, wire 75 maintains tissue-engaging element 72 in an extended set shape, corresponding to length L0. In some implementations, via engagement with interface 77 of head 76, a driver is configured to anchor anchor 70c into a tissue by screwing tissue-engaging element 72 into the tissue. In some implementations, the inner coil of wire 75 is then unscrewed, e.g., turned counter-clockwise, and removed from anchor 70c. In some implementations, the outer coil of tissue-engaging element 72 then relaxes to its shape-set pitch and thereby to its reduced length.

[0258] In some implementations, driver 81 comprises a rod 89 disposed within a tube 88. Rod 89 is configured to engage interface 77. In some implementations, prior to screwing of anchor 70 into tissue 8, tube 88 is coupled to coiled wire 75, while coiled wire 75 is disposed within tissue-engaging element 72, such that driver 81 and anchor 70 are delivered as a unit to tissue 8.

[0259] In some implementations, driver 81 is configured to engage anchor 70 via engagement of rod 89 with interface 77, the driver being configured to screw tissue-engaging element 72 into tissue 8 while coiled wire 75 is coupled to tube 88, i.e., extends distally from tube 88 along the helical channel. In some implementations, tube 88 and rod 89 are configured to rotate as a unit, e.g., in a clockwise direction, while rod 89 applies torque to interface 77 to screw tissue-engaging element 72 into tissue 8 (Fig. 16A). In this figure, tissue-engaging element 72 has length L0 within the tissue.

[0260] In some implementations, once tissue-engaging element 72 is fully screwed into tissue 8, tube 88 is disengaged or uncoupled from rod 89 and is rotated in an opposite, e.g., counter-clockwise, direction. Rod 89 remains engaged with interface 77. In some implementations, tube 88 is configured to retract from tissue 8 in a manner that unscrews coiled wire 75 from within the helical channel (not visible), such that helical tissue-engaging element 72 begins to relax within tissue 8 (Fig. 16B). In some implementations, as tube 88 retracts, coiled wire 75 is removed from the helical channel of tissue-engaging element 72 encircling rod 89 as the wire gradually rotates in a proximal direction. In this figure, a distal part of tissue-engaging element 72 is relaxing to its compressed shape as the wire unscrews, while a proximal part of tissue-engaging element 72 remains in an extended shape.

[0261] In some implementations, once tube 88, coupled to coiled wire 75, has been fully unscrewed from tissue 8, tissue-engaging element 72 becomes fully relaxed, i.e., compressed, in tissue 8, as represented by length LI (Fig. 16C). In some implementations, rod 89 is then uncoupled from interface 77 and retracted proximally (Fig. 16D). As tissueengaging element 72 compresses, the tissue becomes squeezed between the series of helical turns, thus inhibiting the anchor from unscrewing, as described in more detail herein above.

[0262] Reference is now made to Figs. 17A-C, which are schematic illustrations of a system 180 comprising a helical tissue anchor 80, in accordance with some implementations. Similar to implementations shown in Figs. 10A-16D above, anchor 80 illustrates a mechanism for accomplishing contraction/compression of a tissue-engaging element within the tissue in order to squeeze the tissue between turns of the helical tissue-engaging element. Fig. 17A shows tissue anchor 80 being delivered to tissue 8, Fig. 17B shows the anchor being driven into the tissue, and Fig. 17C shows the anchor fully deployed within the tissue.

[0263] In some implementations, anchor 80 comprises a head 86 comprising an interface 87. A tissue-engaging element 82 comprising a series of helical turns extends away from head 86. Tissue-engaging element 82 is formed from a shape memory material that has a first shape, e.g., an increased length L0 (having an increased pitch), when cooled and maintained below its transition temperature. In some implementations, when tissueengaging element 82 reaches the transition temperature, it transitions to a pre-defined set shape, e.g., a reduced length LI (having a reduced pitch).

[0264] In some implementations, system 180 comprises a delivery tool 83 for transluminally advancing and anchoring anchor 80 into a tissue 8. In some implementations, delivery tool 83 comprises a catheter 85, transluminally advanceable to the tissue, and a rod 89, e.g., a driver, configured to advance anchor 80 through catheter 85 to the tissue.

[0265] In some implementations, while delivery tool 83, e.g., driver 89, advances anchor 80 through catheter 85, a cooled fluid 7, e.g., saline, is streamed through catheter 85 to anchor 80. Cooled fluid 7 is below 37 degrees Celsius, e.g., 30-35 degrees Celsius. In some implementations, system 180 is configured to maintain tissue-engaging element 82 in its extended shape by flowing fluid 7 over and around the tissue-engaging element, within catheter 85, thereby maintaining the tissue-engaging element below its transition temperature (Fig. 17A).

[0266] In some implementations, driver 89 is configured, via engagement with head 86, to drive tissue-engaging element 82 into tissue 8. This driving may occur while tissue-engaging element 82 remains in its extended shape (Fig. 17B). [0267] In some implementations, upon reaching the transition temperature, tissueengaging element 82 transitions away from first shape L0 and toward pre-defined set shape LI, i.e., contracts within tissue 8, such that tissue 8 becomes squeezed between helical turns of tissue-engaging element 82, and enhancing the hold of anchor 80 on tissue 8 (Fig. 17C).

[0268] Reference is now made to Figs. 18A-C, 19A-C, and 20A-B, which are schematic illustrations of an example system comprising an example helical tissue anchor 90, in accordance with some implementations. In some implementations, anchor 90 comprises a foot configured as a platform or grip-body through which a helical tissue-engaging element is configured to be threaded. By maintaining contact of a flat surface of the anchor with the tissue and maintaining pressure against the tissue, the foot advantageously provides added stability during the anchoring process by stabilizing the tissue-engaging element within the tissue. In some clinical situations, the anchor may need to be anchored in a heart of a subject in an area of a critical anatomical feature, e.g., a coronary artery near a surface of the tissue. In such cases, an anchor with a short tissue-engaging element may be needed. The foot advantageously allows adjustment of a length of the tissue-engaging element of a standard anchor, providing stability to the anchor even when only partially screwed into the tissue.

[0269] As shown in Figs. 18A-C, in some implementations, anchor 90 comprises a head 96 having an interface 97 engageable with a driver. In some implementations, helical tissueengaging element 92 extends distally from head 96 to define an anchor axis AA of anchor 90. In some implementations, a foot 95, e.g., a grip-body or platform, defines a tissue-facing surface 99 facing distally away from the head. In some implementations, a spring 94 is mounted between head 96 and foot 95, such that screwing of tissue-engaging element 92 distally along thread 91 compresses spring 94 between head 96 and foot 95.

[0270] In some implementations, foot 95 defines a thread 91, complementary to and threadedly engaged with tissue-engaging element 92, running along an inner face of foot 95. In some implementations, thread 91 matches a pitch of tissue-engaging element 92, such that tissue-engaging element 92 is configured to be screwed distally along thread 91 and into the tissue 8 by torque applied to head 96.

[0271] In some implementations, rather than an open-faced thread or groove on the inner face of foot 95, thread 91 is a helical channel extending through foot 95. In some implementations, thread 91 enables screwing of tissue-engaging element 92 through respect to foot 95 while inhibiting pivoting of the tissue-engaging element with respect to the foot. In some implementations, tissue-facing surface 99 may define, include, or support a series of protrusions or edges acting as friction features or grips, such as studs 98 or cleats (Figs. 18 A, B), or corrugated ridges 93 (Fig. 18C) configured to grip or engage the tissue.

[0272] In some implementations, tissue-engaging element 92 is coaxial with spring 94. In some implementations, tissue-engaging element 92 is disposed within an inner diameter of spring 94. In some implementations, spring 94 may be configured to have a stiffness less than that of tissue-engaging element 92. In Figs. 18A-20B, spring 94 is shown to have the same handedness as tissue-engaging element 92. In some other implementations, spring 94 may have an opposite handedness to tissue-engaging element 92.

[0273] Figs. 19A-C show an example process/method of anchoring anchor 90 into tissue 8 by a driver (not shown). As tissue-engaging element 92 is screwed into the tissue, foot 95, e.g., tissue-facing surface 99 thereof, rests on a surface of tissue 8.

[0274] In some implementations, optional friction features or grips, e.g., studs 98, can be provided to engage the tissue (Fig. 19A).

[0275] In some implementations, the anchor is configured such that, as tissue-engaging element 90 is inserted into the tissue, pressure exerted by spring 94 on foot 95 may stabilize helical tissue-engaging element 92 along anchor axis AA.

[0276] In some implementations, the anchor is configured such that, as tissue-engaging element 90 is inserted into the tissue, pressure exerted by spring 94 on foot 95 may inhibit passive rotation of foot 95 with respect to tissue-engaging element 92.

[0277] In some implementations, the anchor is configured such that, as tissue-engaging element 90 is inserted into the tissue, pressure exerted by spring 94 on foot 95 may push the grips of tissue-facing surface 99 onto the surface of the tissue (Fig. 19B).

[0278] In some implementations, spring 94 is rotatable with respect to both head 96 and foot 95. In some implementations, spring 94 is fixed with respect to head 96, and is rotatable with respect to foot 95.

[0279] Fig. 19B shows tissue-engaging element 92 having been driven into tissue 8 to an intermediate depth, with spring 94 partially compressed. Anchor 90 can be inserted to various depths as desired by the end user. The grip-body, platform, or foot 95 can contact the tissue and provide stability, support, resist unintentional withdrawal (e.g., unintentional unscrewing), resist unintended angle changes, etc. of the anchor at a variety of depths. The end user can select different depths as desired. [0280] Fig. 19C shows tissue-engaging element 92 having been driven fully into tissue 8, with spring 94 completely compressed.

[0281] In some implementations, the grip-body, platform, or foot 95 is configured to provide stability for the anchor at a variety of depths. In some implementations, it may be desired to fully insert an anchor for added retention in the tissue. In some implementations, it may be desired to only partially insert an anchor into the tissue to avoid over insertion and/or to avoid anatomical features (e.g., to avoid puncturing a nearby blood vessel). In some systems with multiple anchors, it may be desired to insert some anchors fully (e.g., to maximize retention) and other anchors only partially (e.g., to reduce the likelihood of puncturing a blood vessel in the area.)

[0282] In some systems, multiple of anchor 90 (e.g., 2-30 anchors) can be provided and/or used. In some implementations, the multiple anchors 90 can be connected via a tether, wire, line, suture, etc. In some implementations, the tether, wire, line, suture, etc. can be used to apply forces (e.g., tension) to the anchors for a treatment (e.g., annuloplasty, etc.)

[0283] Figs. 20A-B show an example process/method of anchoring anchor 90 into a tissue having a critical anatomical structure such as a blood vessel BV close to the surface of tissue 8, i.e., directly in a potential path of tissue-engaging element 92. Responsively to identifying/locating blood vessel BV (e.g. using medical imaging techniques), the physician can choose to anchor 90 only partially into tissue 8, i.e., stopping before a distal tip of tissueengaging element 92 reaches the blood vessel. In some implementations, tissue-facing surface 99 of foot 95 acts as a base to stabilize anchor 90. In some implementations, spring 94 provides a counterforce to stabilize a portion of tissue-engaging element 92 that remains outside of tissue 8. Thus, anchor 90 can behave as a fully-anchored anchor whose anchor head is pressed against the surface of the tissue, even when anchor 90 is only partially anchored, e.g., with foot 95 serving as a surrogate anchor head.

[0284] Reference is now made to Fig. 21, which is a schematic illustration of an example system comprising a pair of helical tissue anchors, showing a mechanism for enhancing the anchoring within the tissue by the interlocking of two tissue-engaging elements, in accordance with some implementations. The two anchors are driven (e.g. obliquely) into the tissue so that their tissue-engaging elements engage (e.g. interlock, interlace, or intertwine) with each other within the tissue. For example, the tissue-engaging elements of the two anchors may converge within the tissue. [0285] To achieve this, the anchors may be driven in converging directions - e.g. both anchors pointing and being driven before an anchor point AP. In the particular example shown, the two anchors are driven into the tissue at approximately 45 degrees (but other angles are possible) to a surface of the tissue, and at 90 degrees (but other angles are possible) with respect to each other. Though the process/method of anchoring the two anchors into the tissue requires several steps, in Fig. 21, the pair of tissue anchors is shown extending from the delivery tool after each tissue-engaging element has already been screwed by the respective driver in an interlocking manner.

[0286] In some implementations, system 194 comprises a delivery tool 198, comprising a first driver 199a and a second driver 199b. In some implementations, each driver 199a, 199b is disposed within a respective catheter 191a, 191b, each catheter 191 disposed within delivery tool 198, e.g., within a common sheath 195 of delivery tool 198. Each driver 199 may be rotatable within its respective catheter 191. One or both catheters 191 may be rotatable within sheath 195.

[0287] A first anchor 190a comprises a first head 196a comprising an interface 197a engageable by first driver 199a. Extending distally from head 196a, a first helical tissueengaging element 192a defines an anchor axis AA. A second anchor 190b comprises a second head 196b comprising an interface 197b engageable by a second driver 199b. Extending distally from head 196, a second helical tissue-engaging element 192b defines an anchor axis BB.

[0288] Drivers 199a, 199b are configured to extend from catheters 191a, 191b, respectively, and to converge toward each other to drive the respective tissue-engaging elements 190a, 190b into the tissue in an interlocking manner. In some implementations, first driver 199a is configured to advance the first tissue-engaging element 192a into a tissue along anchor axis AA. Subsequently, second driver 199b advances second tissue-engaging element 192b along anchor axis BB into the tissue at an oblique angle with respect to anchor axis AA, such that anchor axis BB transects anchor axis AA (i.e. axes AA and BB converge).

[0289] In some implementations, delivery tool 198 is configured such that drivers 199 diverge upon exiting a lumen of the delivery tool, e.g., a lumen of common sheath 195, and then (i.e. closer to their distal ends) converge. In some such implementations, and as shown, this is achieved by catheters 191 being shape set to diverge from each other (e.g. upon extension from sheath 195), and to have an elbow 193 (193a, 193b) beyond which the catheters converge. That is, catheters 191 may each have a penultimate diverging region rl and a converging terminal region r2, with elbow 193 therebetween. Via elbow 193, regions r2 are oriented to point in a converging direction such that when drivers 199 extend from catheters 191, the drivers point in the converging direction. Thus, drivers 199 are (i) oriented to point anchors 190 toward a common anchoring point AP, and (ii) rotatable and axially slidable within catheters 191, to screw the anchors into the tissue and into engagement with each other.

[0290] In some implementations, an angle of second elbow 193b approximates a mirror image of first elbow 193a. In some implementations, an angle of first elbow 193a is equal to an angle of second elbow 193b. In some implementations, an angle of first elbow 193a is greater than an angle of second elbow 193b.

[0291] In some implementations, first helical tissue-engaging element 192a and second helical tissue-engaging element 192b have the same handedness. In some other implementations, first helical tissue-engaging element 192a has an opposite handedness to second helical tissue-engaging element 192b.

[0292] In some implementations, tissue-engaging element 192b is driven into the tissue such that at least one turn of second helical tissue-engaging element 192b engages (e.g. hooks around) at least one turn of first helical tissue-engaging element 192a within the tissue, thereby interlocking the tissue-engaging elements within the tissue. Thus, in some implementations, one or both of the tissue-engaging elements may be considered to be, or to serve as, a locking pin for the other tissue-engaging element.

[0293] Reference is now made to Figs. 22A-C and 23A-C, which are schematic illustrations of an example system comprising a helical tissue anchor having a locking pin, in accordance with some implementations. The system may also include a driver.

[0294] In some implementations, the locking pin is inserted after the tissue-engaging element of the anchor is driven into the tissue, and inhibits the tissue-engaging element from unscrewing along the path via which it was screwed into the tissue.

[0295] Figs. 22A-C show a process of inserting a locking pin that extends through a series of helical turns of the anchor, and Figs. 23A-C show a process of inserting a locking pin that extends through an eccentric hole in a neck of the anchor. In the implementations shown, the anchor becomes anchored in the tissue by driving a second tissue-engaging element, i.e., the locking pin, into the tissue non-colinearly with the anchor axis in a manner that the pin engages with the anchor. [0296] In some implementations, anchor 110 (e.g., variants 110a, 110b) comprises a screw that defines a head 116 comprising an interface 107 engageable by the driver, and an eccentric hole 114, 111. In some implementations, a helical tissue-engaging element 112 (e.g., variants 112a, 112b) extends away from the head to define an anchor axis AA of the anchor. The screw further comprises a locking pin 113 (e.g., variants 113a, 113b).

[0297] In some implementations, locking pin 113 may comprise one or more unidirectional tabs 115 that enable passage of locking pin 113 through the hole in a first direction, e.g., downward into tissue 8. In some implementations, tabs 115 prevent passage of locking pin 113 through the hole in a second direction, e.g., in a direction that would loosen anchor 110 from the tissue. In some implementations, and as shown in Figs. 22B-C, tabs 115 (115a) may be disposed toward a proximal end of locking pin 113. In some implementations, and as shown in Figs. 23B-C, tabs 115 (115a) may be disposed toward distal end of locking pin 113.

[0298] In some implementations, the driver (not shown) is configured to screw the tissueengaging element 112 into the tissue by applying torque to the head via interface 107. Subsequently, the driver locks the tissue-engaging element 112 into tissue 8 by driving locking pin 113 into the tissue and through the eccentric hole in the screw.

[0299] Figs. 22A-C show an example anchor 110a having a series of colinear holes 114 that penetrate sequential helical turns of tissue-engaging element 112a. In some implementations, a hole 114’ through anchor head 116 may be aligned with holes 114.

[0300] In some implementations, the driver is configured to push pin 113a through the series of holes 114 (and 114’). Pin 113a is driven into the tissue non-colinearly, i.e., parallel, to anchor axis AA.

[0301] In some implementations, tissue-engaging element 112a becomes locked in tissue 8 by pin 113a engaging the tissue-engaging element within the tissue, thus inhibiting unscrewing of the anchor from the tissue. Because pin 113a is driven into the tissue, in some implementations it may be considered to be a second tissue-engaging element.

[0302] Figs. 23A-C show an anchor 110b having an eccentric hole 111 (i.e. lateral to anchor axis AA) that penetrates head 116, e.g., base 460b thereof. In some implementations, head 116, e.g., base 460b thereof, may define a lateral tab 117 in which hole 111 is defined. In some implementations, the driver is configured to push pin 113b through hole 111 in tab 117. [0303] In some implementations, pin 113b is driven into the tissue non-colinearly, i.e., parallel to anchor axis AA. In contrast to locking pin 113a of anchor 110, locking pin 113b may not engage tissue-engaging element 111b within the tissue. In some implementations, p21in 113b extending through hole 111 and into the tissue inhibits rotation of head 116, and anchor 110b as a whole, thereby inhibiting unscrewing of the anchor from the tissue. Because pin 113b is driven into the tissue, in some implementations it may be considered to be a second tissue-engaging element.

[0304] Reference is again made to Fig. 21. In some implementations, second anchor 190b, i.e., tissue-engaging element 192b thereof, may be considered a locking pin for first tissueengaging element 192a. First anchor 190a is advanced to a tissue, and screwed along first anchor axis AA into the tissue. Subsequently, second anchor 190b may be screwed along second anchor axis BB non-colinearly, e.g., obliquely, to anchor axis AA. First anchor 190a becomes locked in tissue 8 by second tissue-engaging element 192b engaging, i.e., interlocking with, first helical tissue-engaging element 192a within the tissue.

[0305] The systems, apparatuses, and techniques described herein can be used in combination with those described in one or more of the following references, each of which is incorporated herein by reference in its entirety. For example, techniques described in one or more of the following references, each of which is incorporated by reference herein for all purposes, can be modified to utilize one or more of the apparatuses (e.g., tissue anchors or particular features thereof) and techniques described herein:

US Patent Application Publication 2021/0145584 to Kasher et al.

PCT Publication WO 2022/172149 to Shafigh et al.

PCT Publication WO 2023/119064 to Herman et al.

PCT Publication WO 2023/114289 to Chau et al.

PCT Publication WO 2023/218368 to Pesach et al.

PCT Publication WO 2024/121770 to Halabi et al.

[0306] Any of the various systems, assemblies, devices, components, apparatuses, etc. in this disclosure can be sterilized (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.) to ensure they are safe for use with subjects, and the methods herein can comprise (or additional methods comprise or consist of) sterilization of the associated system, device, component, apparatus, etc. (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.). Furthermore, the scope of the present disclosure includes, in some implementations, sterilizing one or more of any of the various systems, devices, apparatuses, etc. in this disclosure.

[0307] The techniques, methods, operations, steps, etc. described or suggested herein or in the references incorporated herein can be performed on a living subject (e.g., human, other animal, etc.) or on a simulation, such as a cadaver, cadaver heart, simulator, imaginary person, etc. When performed on a simulation, the body parts, e.g., heart, tissue, valve, etc., can be assumed to be simulated or can optionally be referred to as “simulated” (e.g., simulated heart, simulated tissue, simulated valve, etc.) and can optionally comprise computerized and/or physical representations of body parts, tissue, etc. The term “simulation” covers use on a cadaver, computer simulator, imaginary person (e.g., if they are just demonstrating in the air on an imaginary heart), etc.

[0308] Example Applications (some non-limiting examples of the concepts herein are recited below):

[0309] Example 1. A system for anchoring in a tissue of a subject, the system comprising: (A) a driver; and/or (B) an anchor, comprising: (i) a head, engageable by the driver; and/or (ii) a tissue-engaging element comprising: (1) a tubular member defining a lumen therealong, the tubular member being fixed to the head, and/or extending away from the head to a distal tip of the tubular member; and/or (2) a wire comprising a shape-set end, the shape-set end comprising a set shape, the shape-set end being constrained away from the set shape within the lumen; and/or the driver being configured, via engagement with the head, to anchor the anchor to the tissue by: (i) inserting the tubular member into the tissue, and/or (i) pushing the wire through the tubular lumen such that the shape-set end becomes exposed from the tubular member and relaxes toward the set shape.

[0310] Example 2. The system according to example 1, wherein the tubular member is a tubular helical member, and/or the lumen is a helical lumen, and/or wherein the shapeset end, in the set shape, has a greater curvature than when constrained within the helical lumen.

[0311] Example 3. The system according to example 1, wherein the tubular member is a tubular helical member, and the lumen is a helical lumen, and/or wherein the shape-set end, in the set shape, has a lesser curvature than when constrained within the helical lumen. [0312] Example 4. The system according to any one of examples 1-3, wherein the tubular member is a tubular helical member, and/or the lumen is a helical lumen, and/or wherein the shape-set end is biased to curve in a direction opposite to that of a handedness of the tubular helical member.

[0313] Example 5. The system according to any one of examples 1-4, wherein the lumen comprises a distal opening at the distal tip, and/or the shape- set end of the wire exits the lumen via the distal opening.

[0314] Example 6. The system according to any one of examples 1-5, wherein the wire is formed from nitinol.

[0315] Example 7. The system according to any one of examples 1-6, wherein: (i) the anchor comprises a proximal opening into the lumen, and/or (ii) the wire comprises a stop at a proximal end of the wire, the stop being wider than the proximal opening, thereby preventing the stop from passing beyond the proximal opening and into the lumen.

[0316] Example 8. A system for use with a tissue of a real or simulated subject, the system comprising an anchor that comprises: (A) a helical tissue-engaging element comprising a proximal end and a distal tip, and/or defining an anchor axis of the anchor; and/or (B) a head, comprising: (i) a base, coupled to the proximal end, and/or shaped to define:(l) an interface, (2) multiple petals extending laterally away from the anchor axis; and/or (3) a neck extending axially between the interface and the petals; and/or (ii) a gripbody, comprising multiple grip-body lobes extending laterally away from the anchor axis, the grip-body being rotatably mounted on the neck, each of the grip-body lobes associated with a respective petal, the base being fixed to the tissue-engaging element such that, via application of torque to the interface, the tissue-engaging element is screwable along the anchor axis into the tissue in a manner that brings the petals into contact with the tissue.

[0317] Example 9. The system according to example 8, wherein the petals extend laterally from the anchor axis at least as far as do the grip-body lobes.

[0318] Example 10. The system according to example 8, wherein the grip-body lobes are disposed axially between the interface and the petals.

[0319] Example 11. The system according to example 8, wherein the grip-body is disposed axially between the interface and the petals. [0320] Example 12. The system according to example 8, further comprising a driver, reversibly engageable with the interface in order to apply the torque to the interface.

[0321] Example 13. The system according to example 8, wherein the anchor is configured such that screwing the tissue-engaging element along the anchor axis into the tissue in the manner that brings the petals into contact with the tissue also brings the gripbody lobes into contact with the tissue.

[0322] Example 14. The system according to any one of examples 8-13, further comprising a driver configured to engage the interface and apply the torque to the interface.

[0323] Example 15. The system according to example 14, wherein the driver is configured to unscrew the tissue-engaging element from the tissue by applying reverse torque to the interface.

[0324] Example 16. The system according to any one of examples 8-15, wherein each of the grip-body lobes has a grip configured to grip the tissue, and/or wherein the head has: (A) a first state in which: (i) the petals are positioned with respect to the grip-body such that screwing the helical tissue-engaging element along the anchor axis into the tissue brings the petals and the grip of each grip-body lobe into contact with the tissue, and/or (ii) the grips, once in contact with the tissue, inhibit unscrewing of the tissue-engaging element from the tissue, and/or (B) a second state in which: (i) each petal is positioned with respect to a respective grip-body lobe in a manner that obscures the grip of the respective grip-body lobe, and/or (ii) via application of reverse torque to the interface, the tissue-engaging element is unscrewable along the anchor axis out of the tissue.

[0325] Example 17. The system according to example 16, wherein, in the first state, the grip extends beyond an edge of the respective petal.

[0326] Example 18. The system according to example 16, wherein the grip-body lobes inhibit unscrewing of the tissue-engaging element from the tissue by having a gripdirectionality opposite that of the helical tissue-engaging element.

[0327] Example 19. The system according to example 16: (i) the tissue-engaging element is configured to be screwed into the tissue while the anchor is in the first state; and/or (ii) the head is configured to transition into the second state responsively to the application of the reverse torque to the interface. [0328] Example 20. The system according to example 19, wherein the head is configured to transition into the second state by rotation of the base with respect to the gripbody responsive to the application of the reverse torque to the interface.

[0329] Example 21. The system according to example 19, wherein: (i) the grip-body and at least one of the petals collectively comprise a coupling that comprises a protrusion and an indentation on mutually-facing surfaces of the head; and/or (ii) in the first state, the protrusion is disposed in the indentation in a manner that inhibits transitioning of the head from the first state toward the second state.

[0330] Example 22. The system according to example 21, wherein, in the first state of the anchor, the coupling inhibits rotation of the base with respect to the grip-body.

[0331] Example 23. The system according to example 21, wherein the coupling is associated with a threshold relative-reverse-torque between the base and the grip-body, and/or is configured to release the head to transition from the first state toward the second state by the protrusion moving out of the indentation responsively to relative-reverse-torque between the base and the grip-body exceeding the threshold relative-reverse-torque.

[0332] Example 24. The system according to example 23, wherein the petals are collectively defined by a plate, the plate defining a stop that defines a limit of an extent of rotation of the grip.

[0333] Example 25. The system according to example 24, wherein, via application of the reverse torque to the interface, the anchor is unscrewable along the anchor axis out of the tissue in a manner that: (i) the contact between the grips and the tissue releases the protrusion from the indentation, such that the anchor transitions from the first state to the second state by rotation of the base with respect to the grip-body; (ii) the grip-body reaches the limit of the extent of rotation of the grip-body with respect to the plate, such that the grip-body abuts the stop; and/or (iii) the petal is positioned in the manner that obscures the grip of the respective grip-body lobe.

[0334] Example 26. A system for use with a tissue of a real or simulated subject, the system comprising an anchor that comprises: (A) a helical tissue-engaging element defining a proximal end and a distal tip, and/or defining an anchor axis of the anchor; and/or (B) a head, comprising: (i) a base, coupled to the proximal end, the base comprising an interface; and/or (ii) a grip, (A) the base being fixed to the tissue-engaging element such that, via application of torque to the interface while the head is in a first state, the tissue-engaging element is screwable along the anchor axis into the tissue in a manner that brings the grip into contact with the tissue such that the grip, by gripping the tissue, inhibits unscrewing of the tissue-engaging element from the tissue, and/or (B) the head being configured to facilitate unscrewing of the tissue-engaging element from the tissue responsively to application of reverse torque to the interface by, responsively to application of the reverse torque to the interface, transitioning into a second state via movement of the base with respect to the grip such that the base separates the grip from the tissue by interposing between the grip and the tissue.

[0335] Example 27. The system according to example 26, wherein the interface is fixedly coupled to the tissue-engaging element.

[0336] Example 28. The system according to example 26, wherein the grip is rotatably coupled to the base.

[0337] Example 29. The system according to example 26, wherein the movement is rotation.

[0338] Example 30. The system according to example 26, wherein: (A) the base and the grip collectively define a coupling that comprises a protrusion and an indentation on mutually-facing surfaces of the head, and/or (B) the coupling is associated with a threshold relative-reverse-torque between the base and the grip, and/or the coupling is configured to:

(i) inhibit transitioning of the head from the first state toward the second state while reverse torque applied by the base to the grip is below the threshold relative-reverse-torque, and/or

(ii) release the head to transition from the first state toward the second state by the protrusion moving out of the indentation responsively to the application of the reverse torque to the interface causing the reverse torque applied by the base to the grip to exceed the threshold relative-reverse-torque.

[0339] Example 31. The system according to any one of examples 26-30, wherein a part of the base is disposed axially between the grip and the tissue-engaging element, the part interposing between the grip and the tissue.

[0340] Example 32. The system according to example 31, wherein the part is fixedly coupled to the interface.

[0341] Example 33. The system according to example 31, wherein the part is fixedly coupled to the tissue-engaging element. [0342] Example 34. A system for anchoring in a tissue of a subject, the system comprising: (A) an anchor comprising: (i) a helical tissue-engaging element having a proximal end, and/or defining a longitudinal anchor axis of the anchor; and/or (ii) a head assembly, comprising: (1) a head that comprises an interface, the head fixed to the proximal end via a coupling that is eccentric with respect to the anchor axis, such that the tissueengaging element is screwable into the tissue via application of torque to the interface, and/or (2) a collar, comprising a laterally -oriented eyelet, the collar rotatably coupled to the proximal end; and/or (B) a driver, configured to engage and apply the torque to the interface.

[0343] Example 35. The system according to example 34, wherein the collar is disposed between the head and the proximal end.

[0344] Example 36. The system according to example 34, wherein the head is associated with a circumference, and/or the anchor is configured such that the application of the torque to the interface by the driver rotates the head and the tissue-engaging element while the collar periodically extends beyond the circumference.

[0345] Example 37. The system according to example 34, wherein, while the interface is engaged by the driver, applying torque to the interface rotates the head and the helical tissue-engaging element.

[0346] Example 38. The system according to example 34, wherein the coupling is eccentric with respect to the head.

[0347] Example 39. The system according to example 34, wherein the eccentricity of the coupling with respect to the anchor axis is provided by the proximal end being eccentric to the anchor axis.

[0348] Example 40. The system according to example 34, wherein the interface comprises a central slot via which the driver is configured to apply the torque.

[0349] Example 41. The system according to example 34, wherein the eyelet is configured to allow passage of a wire in a manner that applying tension to the wire maintains the collar in a fixed orientation with respect to the anchor axis.

[0350] Example 42. The system according to example 41, wherein, while the interface is engaged by the driver and the wire is under tension, the head rotates with respect to the collar. [0351] Example 43. The system according to any one of examples 34-42, wherein: (i) the anchor axis is disposed along a center of the helical tissue-engaging element; and/or (ii) the proximal end comprises a shaft that is parallel to the anchor axis and eccentric with respect to the anchor axis.

[0352] Example 44. The system according to example 43, wherein the collar is rotatably coupled to the proximal end by the shaft extending through the collar.

[0353] Example 45. The system according to example 44, wherein the shaft is eccentric with respect to the collar.

[0354] Example 46. The system according to example 44, wherein the eyelet is transverse with respect to the shaft.

[0355] Example 47. The system according to any one of examples 34-46, wherein the head comprises a recess in a perimeter thereof, within which an upper aspect of the collar is configured to rotate.

[0356] Example 48. The system according to example 47, wherein the collar comprises a tapered surface, and/or is rotatably coupled to the proximal end such that rotation of the collar with respect to the head slides the tapered surface under the head.

[0357] Example 49. Apparatus, for use in a real or simulated heart of a real or simulated subject, the apparatus comprising an anchor that comprises: (i) a tissue-engaging element that defines an anchor axis of the anchor; (ii) a head comprising an interface, the head fixed to a proximal end of the tissue-engaging element such that the tissue-engaging element is screwable into tissue of the real or simulated heart via application of torque to the interface; and/or (iii) a collar, comprising an eyelet, and/or coupled to the proximal end such that the collar is rotatable around a collar axis that is lateral to, and/or parallel with, the longitudinal axis.

[0358] Example 50. A method for anchoring in a valve of a real or simulated heart of a real or simulated subject, the method comprising: (A) advancing multiple anchors to the real or simulated heart, each anchor including: (i) a tissue-engaging element that defines an anchor axis of the anchor; (ii) a head, fixed to a proximal end of the tissue-engaging element; and/or (iii) a collar, comprising a laterally-oriented eyelet, and/or coupled to the proximal end such that the collar is rotatable around a collar axis that is lateral to, and/or parallel with, the anchor axis; and/or (B) anchoring, using a driver, the tissue-engaging element of each anchor within an annulus of the valve; (C) within the real or simulated heart, applying tension to a wire that is threaded through the eyelet of each collar such that the wire: (i) draws the anchors toward each other, and/or (ii) pulls the eyelet of at least one of the anchors to rotate around the collar axis and away from the anchor axis.

[0359] Example 51. The method according to example 50, wherein applying tension to the wire comprises applying tension to the wire in a manner that draws the anchors medially with respect to a curve defined by the wire in response to anchoring the anchors around the valve.

[0360] Example 52. The method according to example 50, wherein the method further comprises applying torque to the head in a manner that the tissue-engaging element rotates into the annulus along the anchor axis while the collar rotates around the collar axis.

[0361] Example 53. The method according to example 50, wherein: (A) advancing the multiple anchors comprises advancing the multiple anchors through a catheter to the real or simulated heart, (B) the collar comprises a beveled surface facing the head, and/or (C) the method further comprises, for at least one of the multiple anchors, subsequent to anchoring the tissue-engaging element within the valve: (i) moving the catheter distally over the head and against the beveled surface in a manner that rotates the collar around the collar axis toward the anchor axis, and/or (ii) using the driver, de-anchoring the tissue-engaging element from the annulus.

[0362] Example 54. A system for anchoring in a tissue, the system comprising: (A) a delivery tool; (B) an anchor, comprising: (i) a head; and/or (ii) a helical tissue-engaging element, extending distally from the head to define an anchor axis of the anchor; and/or (iii) a stabilizer defined by a resilient wire having a first end that is fixedly coupled to the head, the delivery tool being configured to deliver the anchor to the tissue while the wire is constrained around the head, a free end of the wire being biased to deflect laterally from the head responsively to deployment from the delivery tool.

[0363] Example 55. The system according to example 54, wherein the stabilizer is configured, upon deployment from the delivery tool, to at least partially unwrap from a coiled position in which it was disposed within the delivery tool, such that the stabilizer extends beyond a lateral extent of the helical tissue-engaging element.

[0364] Example 56. The system according to example 54, wherein the stabilizer is biased to deflect laterally from the head beyond a lateral extent of the helical tissue-engaging element. [0365] Example 57. The system according to example 54, wherein the stabilizer comprises an elastic material, and/or is constrained within the delivery tool during delivery.

[0366] Example 58. The system according to example 54, wherein, responsively to deployment from the delivery tool, the stabilizer deflects laterally away from the head.

[0367] Example 59. The system according to example 54, wherein in a deployed state, the stabilizer is substantially planar, such that when the anchor is deployed into the tissue, the stabilizer rests on a surface of the tissue.

[0368] Example 60. The system according to example 54, wherein in a delivery state, the stabilizer extends at least 180 degrees around the head.

[0369] Example 61. The system according to example 54, wherein in a delivery state, the stabilizer extends less than 360 degrees around the head.

[0370] Example 62. The system according to example 54, wherein in a deployed state, the stabilizer extends at least 180 degrees around the head.

[0371] Example 63. The system according to example 54, wherein in a deployed state, the stabilizer extends at least 220 degrees around the head.

[0372] Example 64. The system according to example 54, wherein in a deployed state, the stabilizer extends less than 300 degrees around the head.

[0373] Example 65. The system according to example 54, wherein in a deployed state, the stabilizer extends less than 280 degrees around the head.

[0374] Example 66. The system according to any one of examples 54-65, wherein: (i) the head comprises an eyelet, and/or (ii) the stabilizer is rotatably fixed with respect to the eyelet, such that when the stabilizer deflects laterally from the head, the stabilizer is circumferentially oriented with respect to the eyelet.

[0375] Example 67. The system according to example 66, wherein: (i) the system comprises a tether threaded through the eyelet, the tether configured to exert a lateral force on the eyelet in a manner that would bias the anchor to tilt in a direction of the exerted lateral force; and/or (ii) the stabilizer is configured to advantageously inhibit tilting of the anchor in the direction of the exerted lateral force.

[0376] Example 68. The system according to example 66, wherein the stabilizer is biased to deflect laterally from the head beyond a lateral extent of the eyelet. [0377] Example 69. A system for use at a tissue of a real or simulated subject, the system comprising an anchor that comprises: (A) a head; and/or (B) a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue, wherein: (i) at a distal end of the tissue-engaging element, a distal pair of adjacent helical turns of the series has a first inter-turn gap therebetween, and/or (ii) proximal from the distal pair, a proximal pair of adjacent helical turns of the series has a second inter-turn gap therebetween, the second inter-tum gap being smaller than the first inter-turn gap.

[0378] Example 70. The system according to example 69, wherein the tissue-engaging element has a helix diameter that is constant along the series of helical turns.

[0379] Example 71. The system according to example 69, wherein: (A) the head defines an interface, and/or (B) the system further comprises a driver configured to, via engagement with the interface, screw the tissue-engaging element into the tissue such that (i) a first amount of screwing of the tissue-engaging element into the tissue captures a part of the tissue in the first inter-tum gap, and/or (ii) further screwing of the tissue-engaging element into the tissue places the part of the tissue in the second inter-turn gap, such that the part of the tissue becomes compressed between the proximal pair of adjacent helical turns.

[0380] Example 72. The system according to example 69, wherein the series of helical turns includes, proximal from the proximal pair of adjacent helical turns, an other pair of adjacent helical turns of the series, the other pair of adjacent helical turns having an other inter-turn gap therebetween, the other inter-turn gap being greater than the second inter-tum gap-

10381] Example 73. The system according to example 69, wherein the proximal pair of adjacent helical turns is located in a midsection of the series of helical turns.

[0382] Example 74. The system according to example 69, wherein the proximal pair of adjacent helical turns is located at a proximal end of the series of helical turns.

[0383] Example 75. The system according to example 69, wherein the helical tissueengaging element comprises a wire, a midsection of the wire being thicker than the proximal end.

[0384] Example 76. The system according to example 69, wherein the helical tissueengaging element comprises a wire, a midsection of the wire being thicker than the distal end. [0385] Example 77. The system according to any one of examples 69-76, wherein the tissue-engaging element has a gauge that is greater at the proximal pair than at the distal pair.

[0386] Example 78. The system according to example 71, wherein the tissue-engaging element has a pitch that is constant along the series of helical turns.

[0387] Example 79. The system according to example 71, wherein the second interturn gap is smaller than the first inter-turn gap by 1 mm, Example 1.5 mm, or 2 mm.

[0388] Example 80. The system according to example 71, wherein the second interturn gap is smaller than the first inter-turn gap by 10%, 20%, 30%, 40%, or 50%.

[0389] Example 81. The system according to any one of examples 69-80, wherein the tissue-engaging element has a pitch that is smaller at the proximal pair than at the distal pair.

[0390] Example 82. The system according to example 75, wherein the tissue-engaging element has a gauge that is constant along the series of helical turns.

[0391] Example 83. The system according to example 75, wherein the second interturn gap is smaller than the first inter-turn gap by 1 mm, Example 1.5 mm, or 2 mm.

[0392] Example 84. The system according to example 75, wherein the second interturn gap is smaller than the first inter-turn gap by 10%, 20%, 30%, 40%, or 50%.

[0393] Example 85. A system for use at a tissue of a real or simulated subject, the system comprising an anchor that comprises: (A) a head; and/or (B) a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue, wherein: (i) a first pair of adjacent helical turns of the series has a first pitch, and/or (ii) distal from the first pair, a second pair of adjacent helical turns of the series has a second pitch, the second pitch being greater than the first pitch.

[0394] Example 86. A system for use at a tissue of a real or simulated subject, the system comprising an anchor that comprises: (A) a head; and/or (B) a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue, wherein: (i) a first pair of adjacent helical turns of the series has a first gauge, and/or (ii) proximal from the first pair, a second pair of adjacent helical turns of the series has a second gauge, the second gauge being greater than the first gauge, a pitch of the tissue-engaging element being constant along a length of the series. [0395] Example 87. A system for anchoring in a tissue of a real or simulated subject, the system comprising: (A) an anchor, comprising: (i) a head comprising an interface; and/or (ii) a tissue-engaging element extending helically away from the head, and/or defining a helical channel therealong, the tissue-engaging element having a pitch; (B) a wire extending along the helical channel; and/or (C) a driver configured, via engagement with the head, to anchor the anchor to the tissue by: (i) screwing the tissue-engaging element into the tissue, and/or (ii) subsequently, reducing the pitch of the tissue-engaging element by extracting the wire from the helical channel.

[0396] Example 88. The system according to example 87, wherein the tissue-engaging element is elastically deformable.

[0397] Example 89. The system according to example 87, wherein the tissue-engaging element is plastically deformable.

[0398] Example 90. The system according to example 87, wherein the wire is shaped as a series of coils having a pitch greater than the pitch of the tissue-engaging element.

[0399] Example 91. The system according to example 87, wherein the wire is configured to remain within the helical channel after anchoring of the anchor to the tissue.

[0400] Example 92. The system according to example 87, wherein the wire is configured to be removed from the anchor after anchoring of the anchor to the tissue.

[0401] Example 93. The system according to example 87, wherein the helical channel comprises a groove running along an inner curve of the tissue-engaging element.

[0402] Example 94. The system according to example 87, wherein: (i) the wire is a coiled wire; (ii) the driver comprises a rod within a tube, the rod engaging the interface, and/or the tube coupled to the coiled wire; (iii) the driver is configured to screw the tissueengaging element into the tissue while the coiled wire extends distally from the tube along the helical channel; and/or (iv) the tube is configured to retract from the tissue in a manner that unscrews the coiled wire from within the helical channel, such that the tissue-engaging element relaxes within the tissue into a shape having the reduced pitch.

[0403] Example 95. The system according to any one of examples 87-94, wherein the wire defines a stiff inner coil within an outer coil defined by the tissue-engaging element, the outer coil being: (i) an elastically deformable tube comprising a shape- set material, and/or (ii) biased toward a shape-set pitch less than that of the inner coil. [0404] Example 96. The system according to example 95, wherein the head comprises an interface, and/or the driver comprises an interface-engaging rod and a tube through which the rod is configured to pass, the tube fixedly coupled to the stiff inner coil.

[0405] Example 97. The system according to example 95, wherein: (i) the outer coil comprises a shape-set material defining a compressed set shape; and/or (ii) the inner coil comprises a shape-set material defining an extended set shape.

[0406] Example 98. The system according to example 97, wherein: (i) the inner coil, extending through the helical channel, maintains the tissue-engaging element in the extended set shape; and/or (ii) extracting the inner coil proximally through the helical channel relaxes the outer coils of the tissue-engaging element to assume the compressed set shape.

[0407] Example 99. A system for anchoring in a tissue of a real or simulated subject, the system comprising: (A) an anchor, comprising: (i) a head; and/or (ii) a tissue-engaging element extending helically away from the head, and/or defining a helical lumen therealong, the tissue-engaging element defining a first pitch; (B) a wire extending along the helical channel; and/or (C) a driver configured, via engagement with the head, to anchor the anchor to the tissue by: (i) screwing the tissue-engaging element into the tissue, and/or (ii) subsequently, plastically deforming the tissue-engaging element to have a reduced pitch by applying tension to the wire.

[0408] Example 100. The system according to example 99, wherein the wire is configured to remain attached to a distal tip of the tissue-engaging element after the driver is detached from the anchor.

[0409] Example 101. The system according to example 99, wherein, upon the driver applying proximal tension to the wire, the wire is configured to detach from a distal tip of the tissue-engaging element.

[0410] Example 102. A system for anchoring in a tissue, the system comprising: (A) an anchor, comprising: (i) a head; and/or (ii) a helical tissue-engaging element: (1) configured to be screwed into the tissue, (2) defining a helical channel therealong, and/or (3) biased toward having a first pitch; and/or (B) a wire extending helically along the helical channel in a manner that constrains the helical tissue-engaging element to have a second pitch that is greater than the first pitch.

[0411] Example 103. The system according to example 102, wherein the helically- extending wire is shaped as a fixed series of coils having the second pitch. [0412] Example 104. The system according to example 102, wherein the helical channel defines a lumen.

[0413] Example 105. The system according to example 102, wherein the helical channel defines a groove running along an inside aspect of the helical tissue-engaging element.

[0414] Example 106. The system according to example 102, wherein the second pitch is greater than the first pitch.

[0415] Example 107. The system according to any one of examples 102-106, further comprising a driver configured, via engagement with the head, to anchor the anchor to the tissue by: (i) screwing the tissue-engaging element into the tissue, and/or (ii) subsequently, restoring the first pitch to the tissue-engaging element by extracting the wire from the helical channel.

[0416] Example 108. The system according to example 107, wherein the wire is a component of the driver.

[0417] Example 109. The system according to example 107, wherein the wire is a component of the anchor, the driver being configured to engage the anchor by engaging both the head and the wire.

[0418] Example 110. A system for anchoring in a tissue of a real or simulated subject, the system comprising: (A) an anchor, comprising: (i) a head; and/or (ii) an outer helical tissue-engaging element extending helically away from the head, and/or defining a helical channel therealong, the outer helical tissue-engaging element biased toward a first pitch; (B) an inner helical element disposed along the helical channel, the inner helical element defining a second pitch that is greater than the first pitch; and/or (C) a driver configured, via engagement with the head, to anchor the anchor to the tissue by: (i) screwing the outer helical tissue-engaging element and the inner helical element into the tissue while the inner helical element remains disposed along the helical channel, and/or (ii) subsequently, triggering the outer helical tissue-engaging element to transition toward the first pitch by extracting the inner helical element from the helical channel and the tissue.

[0419] Example 111. The system according to example 110, wherein the inner helical element is stiffer than the helical tissue-engaging element. [0420] Example 112. The system according to example 110, wherein a thickness of the inner helical element is greater than half a thickness of the outer helical tissue-engaging element.

[0421] Example 113. A method for use with cardiovascular tissue of a real or simulated subject, the method comprising: (i) transluminally advancing an anchor to the tissue, the anchor having a helical tissue-engaging element that defines a pitch; (ii) subsequently, screwing the helical tissue-engaging element of the anchor into the tissue; and/or (iii) while the tissue-engaging element remains screwed into the tissue, reducing the pitch of the tissueengaging element.

[0422] Example 114. The method according to example 113, wherein the method further comprises: (i) while a coiled wire is disposed along a helical channel defined by the helical tissue-engaging element, screwing the helical tissue-engaging element into the tissue by engagement of a head of the anchor with a driver; and/or (ii) disengaging the driver from the tissue in a manner that removes the coiled wire from within the helical tissue-engaging element, thereby reducing the pitch of the tissue-engaging element.

[0423] Example 115. The method according to example 113, further comprising disengaging the driver from the head.

[0424] Example 116. A system for anchoring in a tissue of a real or simulated subject, the system comprising: (A) an anchor, comprising: (i) a head; and/or (ii) a tissue-engaging element, extending away from the head, having a first shape, and/or formed from a shape memory material that has a transition temperature of below 37 degrees Celsius such that, upon reaching the transition temperature, the tissue-engaging element transitions away from the first shape and toward a pre-defined set shape; and/or (B) a delivery tool comprising: (i) a catheter, transluminally advanceable to the tissue; and/or (ii) a driver, configured to advance the anchor through the catheter to the tissue, wherein: (1) the delivery tool is configured to, while the driver advances the anchor through the catheter, maintain the tissueengaging element in the first shape by maintaining the tissue-engaging element below the transition temperature by streaming a fluid through the catheter to the anchor, and/or (2) the driver is configured, via engagement with the head, to drive the tissue-engaging element into the tissue while the tissue-engaging element remains in the first shape. [0425] Example 117. The system according to example 116, wherein, during advancement of the catheter to the tissue, the streaming fluid is maintained at a temperature below the transition temperature.

[0426] Example 118. The system according to example 116, wherein the temperature of the fluid is maintained below 37 degrees Celsius.

[0427] Example 119. The system according to example 116, wherein the fluid comprises normal saline.

[0428] Example 120. The system according to example 116, wherein, upon being driven into the tissue, the tissue-engaging element is configured to assume the pre-defined set shape.

[0429] Example 121. A system for use at a tissue of a real or simulated heart of a real or simulated subject, the system comprising an anchor that comprises: (A) a head; and/or (B) a helical tissue-engaging element, extending distally from the head to define an anchor axis of the anchor; and/or (C) a foot defining: (i) a tissue-facing surface facing distally away from the head; (ii) a thread, complementary to and threadedly engaged with the tissueengaging element, the tissue-engaging element being configured to be screwed distally along the thread and into the tissue by torque applied to the head; and/or (D) a spring, mounted such that screwing of the tissue-engaging element distally along the thread compresses the spring between the head and the foot.

[0430] Example 122. The system according to example 121, wherein the tissueengaging element and the spring are coaxial.

[0431] Example 123. The system according to example 121, wherein the tissueengaging element is disposed coaxially inside of the spring.

[0432] Example 124. The system according to example 121, wherein the spring has a constant selected such that the spring exerts pressure on the foot as the helical tissueengaging element is screwed into the tissue.

[0433] Example 125. The system according to example 121, wherein pressure exerted by the spring on the foot stabilizes the helical tissue-engaging element as the helical tissueengaging element is screwed into the tissue. [0434] Example 126. The system according to example 121, wherein pressure exerted by the spring on the foot stabilizes the helical tissue-engaging element when the helical tissue-engaging element is fully screwed into the tissue.

[0435] Example 127. The system according to example 121, wherein the foot defines grips on the tissue-facing surface.

[0436] Example 128. The system according to example 127, wherein the grips comprise a set of cleats.

[0437] Example 129. The system according to example 127, wherein the grips comprise a series of corrugated ridges.

[0438] Example 130. A method for use at a tissue of a real or simulated subject, the method comprising: (A) advancing a first anchor and a second anchor to the tissue, the first anchor including (i) a first head, and/or (ii) a first helical tissue-engaging element extending from the first head, and/or the second anchor including (i) a second head, and/or (ii) a second helical tissue-engaging element extending from the first head; (B) screwing the first helical tissue-engaging element into the tissue; and/or (C) screwing the second helical tissueengaging element into the tissue at an oblique angle with respect to the first tissue-engaging element, such that at least one turn of the second helical tissue-engaging element hooks around at least one turn of the first helical tissue-engaging element within the tissue.

[0439] Example 131. The method according to example 130, further comprising disengaging the driver from the tissue and removing the driver from the subject.

[0440] Example 132. The method according to example 130, wherein: (i) the first tissue-engaging element defines a first anchor axis, and/or (ii) the second tissue-engaging element defines a second anchor axis, such that screwing the second helical tissue-engaging element into the tissue at an oblique angle with respect to the first tissue-engaging element comprises screwing the second helical tissue-engaging element into the tissue along the second anchor axis at an oblique angle with respect to the first anchor axis.

[0441] Example 133. The method according to any one of examples 130-132, wherein screwing the first helical tissue-engaging element and the second helical tissue-engaging element into the tissue comprises providing a driver having a first driver interface and a second driver interface, such that screwing the first helical tissue-engaging element into the tissue is performed using the first driver interface, and/or screwing the second helical tissueengaging element into the tissue is performed using the second driver interface. [0442] Example 134. The method according to example 133, wherein screwing the second helical tissue-engaging element into the tissue at the oblique angle comprises orienting the second driver interface at the oblique angle before screwing the first anchor into the tissue using the first driver interface, such that screwing the second helical tissueengaging element into the tissue by the second driver interface occurs along a trajectory that intersects with the first anchor.

[0443] Example 135. A method for use at a tissue of a real or simulated subject, the method comprising: (A) advancing an anchor to the tissue, the anchor including (i) a head, and/or (ii) a first tissue-engaging element extending from the first head to define an anchor axis of the anchor; (B) driving the first tissue-engaging element along the anchor axis into the tissue; and/or (C) locking the first tissue-engaging element in the tissue by driving a second tissue-engaging element into the tissue such that, within the tissue, the second tissueengaging element engages the first tissue-engaging element.

[0444] Example 136. A system for anchoring in a tissue, the system comprising: (A) a delivery tool, comprising a first driver and a second driver; (B) a first anchor, comprising: (i) a first head, engageable by the driver; and/or (ii) a first helical tissue-engaging element extending distally from the first head; and/or (C) a second anchor, comprising: (i) a second head, engageable by the driver; and/or (ii) a second helical tissue-engaging element, extending distally from the second head; wherein the delivery tool is configured to: (i) using the first driver, advance the first tissue-engaging element into the tissue, and/or (ii) using the second driver, advance the second tissue-engaging element into the tissue at an oblique angle with respect to the first tissue-engaging element, such that at least one turn of the second helical tissue-engaging element hooks around at least one turn of the first helical tissueengaging element within the tissue.

[0445] Example 137. The system according to example 136, wherein the first tissueengaging element has a handedness opposite to a handedness of the second tissue-engaging element.

[0446] Example 138. The system according to example 136, wherein the first tissueengaging element and the second tissue-engaging element have a same handedness.

[0447] Example 139. A system for anchoring in a tissue, the system comprising: (A) a driver; and/or (B) an anchor, comprising: (i) a screw, that defines: (1) a head, engageable by the driver; and/or (2) a helical tissue-engaging element, extending away from the head to define an anchor axis of the anchor, the screw defining an eccentric hole; and/or (ii) a locking pin; the driver being configured to: (i) screw the tissue-engaging element into the tissue by applying torque to the head, and/or (ii) lock the tissue-engaging element in the tissue by driving the locking pin into the tissue and through the eccentric hole in the screw.

[0448] Example 140. The system according to example 139, wherein the locking pin is eccentric to the anchor axis.

[0449] Example 141. The system according to example 139, wherein the locking pin is parallel to the anchor axis.

[0450] Example 142. The system according to example 139, wherein the locking pin is oblique to the anchor axis.

[0451] Example 143. The system according to example 139, wherein the pin comprises a set of unidirectional tabs configured to: (i) enable passage of the pin through the eccentric hole in a first direction, and/or (ii) prevent passage of the pin through the eccentric hole in a second direction.

[0452] Example 144. The system according to example 139, wherein the head further comprises a tab fixedly attached thereto, and/or the eccentric hole is disposed in the tab lateral to the anchor axis.

[0453] Example 145. The system according to example 139, wherein: (i) the hole aligns with a series of holes in sequential turns of the helical tissue-engaging element, and/or (ii) the driver is further configured to push the pin through the series of holes, in a manner that inhibits unscrewing of the anchor from the tissue.

[0454] Example 146. A method for use at a tissue of a real or simulated subject, the method comprising: (A) advancing an anchor to the tissue, the anchor including (i) a head, and/or (ii) a helical tissue-engaging element extending from the head to define an anchor axis of the anchor; (B) screwing the helical tissue-engaging element along the anchor axis into the tissue; and/or (C) locking the helical tissue-engaging element in the tissue by driving a second tissue-engaging element, engaged with the anchor, into the tissue non-colinearly with the anchor axis.

[0455] Example 147. The method according to example 146, wherein the second tissueengaging element is a pin, and/or locking the tissue-engaging element in the tissue comprises driving the pin, engaged with the anchor, into the tissue through a hole in the anchor eccentric to the anchor axis.

[0456] Example 148. The method according to example 146, wherein: (i) the anchor is a first anchor, and/or the helical tissue-engaging element is a first helical tissue-engaging element; (ii) the second tissue-engaging element is a second helical tissue-engaging element of a second anchor, and/or (iii) locking the first helical tissue-engaging element in the tissue comprises driving the second helical tissue-engaging element into the tissue obliquely to the anchor axis in a manner that it engages with the first helical tissue-engaging element.

[0457] Example 149. The method according to example 146, wherein non-colinearly indicates an oblique angle to the anchor axis.

[0458] Example 150. The method according to example 146, wherein non-colinearly indicates parallel and lateral to the anchor axis.

[0459] Example 151. A system for use at a tissue of a real or simulated heart of a real or simulated subject, the system comprising an anchor that comprises: (A) a head; and/or (B) a tissue-engaging element; and/or (C) a foot defining: (i) a tissue-facing surface facing distally away from the head; (ii) an opening through which at least a portion of the tissueengaging element can pass, such that, as the tissue-engaging element is inserted into tissue, the foot can move along a portion of the tissue-engaging element; and/or (D) a spring, mounted such that, when the foot is engaged with the tissue and the tissue-engaging element is inserted into the tissue, the spring can compress between the head and the foot.

[0460] Example 152. The system according to example 151, wherein the tissueengaging element and the spring are coaxial.

[0461] Example 153. The system according to example 151, wherein the tissueengaging element is disposed coaxially inside of the spring.

[0462] Example 154. The system according to example 151, wherein the spring has a constant selected such that the spring exerts pressure on the foot as the tissue-engaging element is inserted into the tissue.

[0463] Example 155. The system according to example 151, wherein pressure exerted by the spring on the foot stabilizes the tissue-engaging element as the tissue-engaging element is inserted into the tissue. [0464] Example 156. The system according to example 151, wherein pressure exerted by the spring on the foot stabilizes the tissue-engaging element at various depths of insertion into the tissue.

[0465] Example 157. The system according to example 151, wherein pressure exerted by the spring on the foot stabilizes the tissue-engaging element after completion of insertion into the tissue to a final depth.

[0466] Example 158. The system according to example 151, wherein the foot defines friction features on the tissue-facing surface.

[0467] Example 159. The system according to example 158, wherein the friction features comprise a set of cleats.

[0468] Example 160. The system according to example 158, wherein the friction features comprise a series of corrugated ridges.

[0469] Example 161. A system for use at a tissue anchor site of a real or simulated subject, the system comprising: a first anchor, comprising a first head, and/or a first helical tissue-engaging element; a second anchor, comprising a second head, and/or a second helical tissue-engaging element; and/or a delivery tool. The delivery tool comprises a first catheter, a second catheter, a first driver, and/or a second driver. The first catheter and the second catheter each have a distal part comprising a shape- set material, the shape set shaped to define an elbow. The first driver is configured to extend through and/or beyond the first catheter and/or, via engagement with the first head, drive the first helical tissue-engaging element into the tissue. The second driver is configured to extend through and/or beyond the second catheter and/or, via engagement with the second head, drive the second helical tissueengaging element into the tissue. Each elbow is disposed in a manner that, when the respective driver extends through and/or beyond the respective catheter, the second driver converges at the anchor site from an opposing direction to the first driver. The second driver is configured to screw the second helical tissue-engaging element into the tissue at an oblique angle with respect to the first tissue-engaging element, such that at least one turn of the second helical tissue-engaging element hooks around at least one turn of the first helical tissue-engaging element within the tissue.

[0470] Example 162. The system according to example 161, wherein the shape set of the first catheter is configured to cause the distal part of the first catheter to diverge from the distal part of the second catheter upon extension of the first catheter from the delivery tool. [0471] Example 163. The system according to any one of examples 161-162, wherein the shape set of the second catheter is configured to cause the distal part of the second catheter to diverge from the distal part of the first catheter upon extension of the second catheter from the delivery tool.

[0472] Example 164. The system according to any one of examples 161-163, wherein the elbow of the second catheter approximates a mirror image of the elbow of the first catheter.

[0473] Example 165. The system according to any one of examples 161-163, wherein an angle of the first elbow is equal to an angle of the second elbow.

[0474] Example 166. The system according to any one of examples 161-163, wherein an angle of the first elbow is greater than an angle of the second elbow.

[0475] Example 167. A system according to any of the above examples, in which the system, the delivery tool, the driver, the anchor, the head, the tissue-engaging element, and/or the wire is sterilized.

[0476] Although the operations of some of the disclosed methods are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially can in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed systems, apparatuses, devices, methods, etc. can be used in conjunction with other systems, apparatuses, devices, methods, etc.

[0477] The present disclosure is not limited to the examples that have been particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

1. A system for anchoring in a tissue of a subject, the system comprising: a driver; and an anchor, comprising: a head, engageable by the driver; and a tissue-engaging element comprising: a tubular member defining a lumen therealong, the tubular member being fixed to the head, and extending away from the head to a distal tip of the tubular member; and a wire comprising a shape-set end, the shape-set end comprising a set shape, the shape- set end being constrained away from the set shape within the lumen; and the driver being configured, via engagement with the head, to anchor the anchor to the tissue by: inserting the tubular member into the tissue, and pushing the wire through the tubular lumen such that the shape-set end becomes exposed from the tubular member and relaxes toward the set shape.

2. The system according to claim 1, wherein the tubular member is a tubular helical member, and the lumen is a helical lumen, and wherein the shape- set end, in the set shape, has a greater curvature than when constrained within the helical lumen.

3. The system according to claim 1, wherein the tubular member is a tubular helical member, and the lumen is a helical lumen, and wherein the shape- set end, in the set shape, has a lesser curvature than when constrained within the helical lumen.

4. The system according to any one of claims 1-3, wherein the tubular member is a tubular helical member, and the lumen is a helical lumen, and wherein the shape-set end is biased to curve in a direction opposite to that of a handedness of the tubular helical member.

5. The system according to any one of claims 1-4, wherein the lumen comprises a distal opening at the distal tip, and the shape-set end of the wire exits the lumen via the distal opening.

6. The system according to any one of claims 1-5, wherein the wire is formed from nitinol.

7. The system according to any one of claims 1-6, wherein: the anchor comprises a proximal opening into the lumen, and the wire comprises a stop at a proximal end of the wire, the stop being wider than the proximal opening, thereby preventing the stop from passing beyond the proximal opening and into the lumen.

8. A system for anchoring in a tissue of a subject, the system comprising: an anchor comprising: a helical tissue-engaging element having a proximal end, and defining a longitudinal anchor axis of the anchor; and a head assembly, comprising: a head that comprises an interface, the head fixed to the proximal end via a coupling that is eccentric with respect to the anchor axis, such that the tissue-engaging element is screwable into the tissue via application of torque to the interface, and a collar, comprising a laterally -oriented eyelet, the collar rotatably coupled to the proximal end; and a driver, configured to engage and apply the torque to the interface.

9. The system according to claim 8, wherein the collar is disposed between the head and the proximal end.

10. The system according to claim 8, wherein the head is associated with a circumference, and the anchor is configured such that the application of the torque to the interface by the driver rotates the head and the tissue-engaging element while the collar periodically extends beyond the circumference.

11. The system according to claim 8, wherein, while the interface is engaged by the driver, applying torque to the interface rotates the head and the helical tissue-engaging element.

12. The system according to claim 8, wherein the coupling is eccentric with respect to the head.

13. The system according to claim 8, wherein the eccentricity of the coupling with respect to the anchor axis is provided by the proximal end being eccentric to the anchor axis.

14. The system according to claim 8, wherein the interface comprises a central slot via which the driver is configured to apply the torque.

15. The system according to claim 8, wherein the eyelet is configured to allow passage of a wire in a manner that applying tension to the wire maintains the collar in a fixed orientation with respect to the anchor axis.

16. The system according to claim 15, wherein, while the interface is engaged by the driver and the wire is under tension, the head rotates with respect to the collar.

17. The system according to any one of claims 8-16, wherein: the anchor axis is disposed along a center of the helical tissue-engaging element; and the proximal end comprises a shaft that is parallel to the anchor axis and eccentric with respect to the anchor axis.

18. The system according to claim 17, wherein the collar is rotatably coupled to the proximal end by the shaft extending through the collar.

19. The system according to claim 18, wherein the shaft is eccentric with respect to the collar.

20. The system according to claim 18, wherein the eyelet is transverse with respect to the shaft.

21. The system according to any one of claims 8-20, wherein the head comprises a recess in a perimeter thereof, within which an upper aspect of the collar is configured to rotate.

22. The system according to claim 21, wherein the collar comprises a tapered surface, and is rotatably coupled to the proximal end such that rotation of the collar with respect to the head slides the tapered surface under the head.

23. A system for anchoring in a tissue, the system comprising: a delivery tool; an anchor, comprising: a head; and a tissue-engaging element, extending distally from the head; and a stabilizer defined by a resilient wire having a first end that is fixedly coupled to the head, the delivery tool being configured to deliver the anchor to the tissue while the wire is constrained around the head, a free end of the wire being biased to deflect laterally from the head responsively to deployment from the delivery tool.

24. The system according to claim 23, wherein the stabilizer is configured, upon deployment from the delivery tool, to at least partially unwrap from a coiled position in which it was disposed within the delivery tool, such that the stabilizer extends beyond a lateral extent of the tissue-engaging element.

25. The system according to claim 23, wherein the stabilizer is biased to deflect laterally from the head beyond a lateral extent of the tissue-engaging element.

26. The system according to claim 23, wherein the stabilizer comprises an elastic material, and is constrained within the delivery tool during delivery.

27. The system according to claim 23, wherein, responsively to deployment from the delivery tool, the stabilizer deflects laterally away from the head.

28. The system according to claim 23, wherein in a deployed state, the stabilizer is substantially planar, such that when the anchor is deployed into the tissue, the stabilizer rests on a surface of the tissue.

29. The system according to claim 23, wherein in a delivery state, the stabilizer extends at least 180 degrees around the head.

30. The system according to claim 23, wherein in a delivery state, the stabilizer extends less than 360 degrees around the head.

31. The system according to claim 23, wherein in a deployed state, the stabilizer extends at least 180 degrees around the head.

32. The system according to claim 23, wherein in a deployed state, the stabilizer extends at least 220 degrees around the head.

33. The system according to claim 23, wherein in a deployed state, the stabilizer extends less than 300 degrees around the head.

34. The system according to claim 23, wherein in a deployed state, the stabilizer extends less than 280 degrees around the head.

35. The system according to any one of claims 23-34, wherein: the head comprises an eyelet, and the stabilizer is rotatably fixed with respect to the eyelet, such that when the stabilizer deflects laterally from the head, the stabilizer is circumferentially oriented with respect to the eyelet.

36. The system according to claim 35, wherein: the system comprises a tether threaded through the eyelet, the tether configured to exert a lateral force on the eyelet in a manner that would bias the anchor to tilt in a direction of the exerted lateral force; and the stabilizer is configured to advantageously inhibit tilting of the anchor in the direction of the exerted lateral force.

37. The system according to claim 35, wherein the stabilizer is biased to deflect laterally from the head beyond a lateral extent of the eyelet.

38. A system for use at a tissue of a subject, the system comprising an anchor that comprises: a head; and a helical tissue-engaging element extending distally away from the head in a series of helical turns in a manner that defines an anchor axis along which the tissue-engaging element is screwable into the tissue, wherein: at a distal end of the tissue-engaging element, a distal pair of adjacent helical turns of the series has a first inter-turn gap therebetween, and proximal from the distal pair, a proximal pair of adjacent helical turns of the series has a second inter-turn gap therebetween, the second inter-turn gap being smaller than the first inter-turn gap.

39. A system for anchoring in a tissue, the system comprising: an anchor, comprising: a head; and a helical tissue-engaging element: configured to be screwed into the tissue, defining a helical channel therealong, and biased toward having a first pitch; and a wire extending helically along the helical channel in a manner that constrains the helical tissue-engaging element to have a second pitch that is greater than the first pitch.

40. The system according to claim 39, wherein the helically-extending wire is shaped as a fixed series of coils having the second pitch.

41. The system according to claim 39, wherein the helical channel defines a lumen.

42. The system according to claim 39, wherein the helical channel defines a groove running along an inside aspect of the helical tissue-engaging element.

43. The system according to claim 39, wherein the second pitch is greater than the first pitch.

44. The system according to any one of claims 39-43, further comprising a driver configured, via engagement with the head, to anchor the anchor to the tissue by: screwing the tissue-engaging element into the tissue, and subsequently, restoring the first pitch to the tissue-engaging element by extracting the wire from the helical channel.

45. The system according to claim 44, wherein the wire is a component of the driver.

46. The system according to claim 44, wherein the wire is a component of the anchor, the driver being configured to engage the anchor by engaging both the head and the wire.

47. A system for use at a tissue of a heart of a subject, the system comprising an anchor that comprises: a head; and a tissue-engaging element, extending distally from the head; and a foot defining: a tissue-facing surface facing distally away from the head; a thread, complementary to and threadedly engaged with the tissue-engaging element, the tissue-engaging element being configured to be screwed distally along the thread and into the tissue by torque applied to the head; and a spring, mounted such that screwing of the tissue-engaging element distally along the thread compresses the spring between the head and the foot.

48. A system for use at a tissue anchor site of a subject, the system comprising: a first anchor, comprising a first head, and a first helical tissue-engaging element; a second anchor, comprising a second head, and a second helical tissue-engaging element; and a delivery tool, comprising: a first catheter and a second catheter, the first catheter and the second catheter each having a distal part comprising a shape-set material, the shape set shaped to define an elbow, a first driver, configured to extend through and beyond the first catheter and, via engagement with the first head, drive the first helical tissue-engaging element into the tissue, and a second driver, configured to extend through and beyond the second catheter and, via engagement with the second head, drive the second helical tissue-engaging element into the tissue; each elbow disposed in a manner that, when the respective driver extends through and beyond the respective catheter, the second driver converges at the anchor site from an opposing direction to the first driver; the second driver configured to screw the second helical tissue-engaging element into the tissue at an oblique angle with respect to the first tissue-engaging element, such that at least one turn of the second helical tissue-engaging element hooks around at least one turn of the first helical tissue-engaging element within the tissue.

49. The system according to claim 48, wherein the shape set of the first catheter is configured to cause the distal part of the first catheter to diverge from the distal part of the second catheter upon extension of the first catheter from the delivery tool.

50. The system according to any one of claims 48-49, wherein the shape set of the second catheter is configured to cause the distal part of the second catheter to diverge from the distal part of the first catheter upon extension of the second catheter from the delivery tool.

51. The system according to any one of claims 48-50, wherein the elbow of the second catheter approximates a mirror image of the elbow of the first catheter.

52. The system according to any one of claims 48-51, wherein an angle of the first elbow is equal to an angle of the second elbow.

53. The system according to any one of claims 48-52, wherein an angle of the first elbow is greater than an angle of the second elbow.