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WO2025090581A1 - Systèmes et procédés de modulation de flux inverse pour éviter un effondrement de vaisseau pendant une embolectomie - Google Patents

Systèmes et procédés de modulation de flux inverse pour éviter un effondrement de vaisseau pendant une embolectomie Download PDF

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Publication number
WO2025090581A1
WO2025090581A1 PCT/US2024/052527 US2024052527W WO2025090581A1 WO 2025090581 A1 WO2025090581 A1 WO 2025090581A1 US 2024052527 W US2024052527 W US 2024052527W WO 2025090581 A1 WO2025090581 A1 WO 2025090581A1
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Prior art keywords
flow
vessel
pressure
aspiration
catheter
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PCT/US2024/052527
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English (en)
Inventor
James Richard CALDWELL
Dave Scott RHODES
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Crown Range Medical Inc
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Crown Range Medical Inc
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Publication of WO2025090581A1 publication Critical patent/WO2025090581A1/fr
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/22—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/32—Surgical cutting instruments
    • A61B17/3205—Excision instruments
    • A61B17/3207—Atherectomy devices working by cutting or abrading; Similar devices specially adapted for non-vascular obstructions
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B2017/00017—Electrical control of surgical instruments
    • A61B2017/00022—Sensing or detecting at the treatment site
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/06—Measuring instruments not otherwise provided for
    • A61B2090/064—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2217/00—General characteristics of surgical instruments
    • A61B2217/002—Auxiliary appliance
    • A61B2217/005—Auxiliary appliance with suction drainage system

Definitions

  • Flow cessation or flow reversal is one technique to provide protection against embolic debris from entering the cerebral vasculature. This can be achieved using balloon-guide catheters, which can arrest antegrade flow and sometimes achieve reversed flow in the downstream vasculature. Balloon guide catheters are most commonly used in the internal carotid artery during stroke thrombectomy and there is evidence that they help to improve reperfusion quality and clinical outcomes for stroke patients. However, it is known that attempting to reverse flow using catheters can cause arterial collapse which impedes flow reversal, and therefore limits a physician’s ability to capture embolic debris.
  • Described herein are methods and apparatuses (e.g., devices, systems, etc.) for applying, maintaining and controlling flow reversal in the neurovasculature.
  • these methods and apparatuses may include controlling the flow rate applied from a catheter (e.g., a reverse-flow aspiration catheter) based on one or more sensor inputs and based upon the identity and/or nature of the vessel into which the catheter is inserted so that the flow through the vessel is reversed, i.e., flows in an opposite direction as compared to the normal anatomical flow through the vessel, while preventing collapse of the vessel based on modifying flow and pressure parameters.
  • a catheter e.g., a reverse-flow aspiration catheter
  • Flow may be reversed by the application of a controlled, typically low flow (e.g., 250 ml/min or less, 100 ml/min or less, 50 ml/min or less, 20 ml/min or less, 10 ml/min or less, 5 ml/min or less, etc.) and may be adjusted based on automatic, semi-automatic, and/or manual feedback.
  • flow may be reversed by the application of fluid (positive pressure) at one or more other sites, including (but not limited to) the re-introduction of blood previously removed from the patient.
  • the vessel or vessels within which flow is being reversed may be fully or partially occluded over the region within which flow is being reversed.
  • these methods and apparatuses may be used as part of an embolus (e.g., clot) removal procedure and/or re-canalization procedure to restore normal flow within the vessel(s).
  • embolus e.g., clot
  • these methods and apparatuses may be used in conjunction with, and/or may include as part of the method and apparatus, one or more methods and apparatuses for removing clot material, including by aspiration at higher flow rates or vacuum pressures.
  • the methods and apparatuses described herein may be used or useful for positioning and/or preparing embolic material for removal from the vessel with one or more additional and/or accessory apparatuses (e.g., carotid artery stent delivery catheters, aspiration catheters, mechanical retrieval devices, etc.).
  • additional and/or accessory apparatuses e.g., carotid artery stent delivery catheters, aspiration catheters, mechanical retrieval devices, etc.
  • the application of reverse flow as described herein may prevent fragments
  • the system may include: a flow line having a proximal end and a distal end, wherein the proximal end is configured to couple to a source of suction (e.g. vacuum pump), if desired or to a flow control that regulates the source of suction.
  • the flow line may be configured to couple to the venous system (e.g. via a sheath in the femoral vein) to return blood removed by aspiration.
  • the apparatus may include a flowcontrol comprising a valve coupled to, or configured to couple to, a source of suction and/or to atmosphere.
  • the flow control comprises a peristaltic pump coupled to the flow line between the proximal end and the distal end.
  • the system may also include a first pressuresensing site distal to the flow control (e.g., the flow control valve and/or peristaltic pump).
  • the system may include a second pressure-sensing site proximal to the flow control, a first pressure sensor configured to couple to the first pressure-sensing site, a second pressure sensor configured to couple to the second pressure-sensing site, and a flow sensing site somewhere in the flow line.
  • the flow sensor site may be coupled or include a flow sensor that is configured to sense flow (at the flow sensor site) in the flow line.
  • any of these apparatuses may include a controller that is configured to maintain reverse flow and prevent collapse of the vessel.
  • the controller may include one or more processors configured to control the operation of the flow control (e.g., the flow control valve and/or peristaltic pump) based on input from the first pressure sensor, second pressure sensor, flow sensor, and optionally a position sensor of the valve or position and/or rate of the rotation sensor of the peristaltic pump head, flow coefficient curves of the valve and/or distal flow line, control algorithm, and desired flow rate or a vessel optimum reverse flow rate value, to maintain a flow rate through the flow line tubing within a range adapted to reverse arterial flow within a vessel and to avoid collapse of the vessel during aspiration.
  • the flow control e.g., the flow control valve and/or peristaltic pump
  • the pressure controller may comprise a processor configured to control operation of the flow-control valve (and therefore suction from the source of suction/negative pressure) and/or may control a peristaltic pump based on input from the first and second pressure sensors and flow sensor to maintain an aspiration flow rate through the flow line within a range adapted to reverse arterial flow within a vessel and to avoid collapse of the vessel during aspiration when the flow line is in communication with the vessel.
  • distal may refer to the arterial neurovasculature side of the flow control and proximal may refer to the opposite side, whether the flow line is connected into the venous system or not.
  • optimum reverse flow rate may refer to the flow rate the neurovasculature can support without vessel collapse or the clinician’s selected flow rate, whichever is lower.
  • the flow line may be a continuous length of tubing, or a length of tubing that has been connected or joined together.
  • the flow line may have a continuous inner lumen region through which pressure (e.g., suction, aspiration) may be applied, removing blood and/or embolic material from the vessel.
  • the flow line may include one or more valves (e.g., flowcontrol valve) coupled thereto.
  • the flow control valve may be attached over the flow line and/or may be integrated into the flow line.
  • the flow line may be any appropriate material for applying aspiration.
  • the flow line may be a bio-compatible polymeric material.
  • the flow-control valve may be any appropriate flow-control valve, including (but not limited to) a pinch valve, a rotary needle valve, an aperture valve, ball valve, globe valve, butterfly valve, etc.
  • the flow-control valve may be configured to be adjustable to limit flow at relatively low flow rates (e.g., 250 ml/min or less, 100 ml/min or less, 50 ml/min or less, 20 ml/min or less, 10 ml/min or less, 5 ml/min or less, etc.).
  • multiple valves operating together, including in parallel and/or in series may be used to form the flow control valve, and may be alternatively referred to as a flow-control valve assembly.
  • a peristaltic pump may act to modulate flow through the flow line by modulating rotation of a pump head (rather than a flow control valve), with one or more pressure and flow sensing sites on each side of the peristaltic pump on the flow line assembly.
  • the pressure-sensing sites may be fluidly continuous with one or more regions of the flow line.
  • the pressures- sensing sites may include a pressure sensor, or may fluidly couple to a pressure sensor.
  • each pressure-sensing site may include a junction (e.g., T-junction) that include a dead- ended branch line (no flow) in fluid communication with the lumen of the flow line so as to reflect the pressure within the region of the flow line at the pressure-sensing site.
  • the pressure-sensing site includes a structure (e.g., membrane, deflectable member, etc.) that reflects the pressure within the corresponding region of the flow line at the pressuresensing site, at least over a range of pressures to be sensed (e.g., 30 PSI, absolute or less, etc.).
  • a structure e.g., membrane, deflectable member, etc.
  • the first pressure-sensing site may be representative of the pressure distal to the flowcontrol (e.g., distal to a flow valve and/or peristaltic pump).
  • the first pressuresensing site may be positioned within the region of the flow line distal to flow control. More than one distal site (e.g., more than one first pressure-sensing site) may be included and/or used.
  • the second pressure-sensing site may be representative of the pressure proximal to the flow control.
  • the second pressure-sensing site may be positioned within the region of the flow line proximal to flow control. More than one proximal site (e.g., more than one second pressure-sensing site) may be included and/or used.
  • pressure sensors may be used or included.
  • the pressure sensors described herein may be configured to measure vacuum pressure (e.g., negative pressure) that is less than the ambient atmospheric pressure.
  • a pressure sensor may be a piezoelectric pressure sensor, a microelectromechanical (MEMS) pressure sensor, a vibrating/resonance pressure sensor, a variable capacitance pressure sensor, a Pirani-type (e.g., thermal conductivity) pressure sensor, a sealed-chamber (reference) pressure sensor, etc.
  • Pressure sensors may be coupled with transducer protectors to allow measurement of pressure without exposing the pressure sensors to blood.
  • the transducer protectors may be part of the durable assembly or disposable flow line assembly.
  • multiple pressure or flow sensors may be used (e.g., to improve accuracy or to provide redundancy).
  • flow sensors may also be used, including but not limited to in-line or clamp-on flow meters, and the results of the pressure and flow data may be combined (e.g., averaged, etc.) by the controller.
  • the disposable flow line assembly may include an in-line filter assembly either distal or proximal the flow control (e.g., valve and/or peristaltic pump) durable assembly.
  • flow control e.g., valve and/or peristaltic pump
  • these apparatuses and methods of using them may include a controller configured to control operation of the apparatus, and in particular, to control and estimate the flow rate of the fluid conveyed in the tubing while sensing pressures to prevent collapse of the vessel.
  • the controller includes control circuitry and may include one or more processors for processing sensor data (from the one or more, e.g., first pressure sensor, second pressure sensor, motor encoder sensor, flow sensors, etc.).
  • controllers may include sub-system, including a communications sub-system for receiving and/or transmitting, e.g., wirelessly transmitting, data received and/or processed, including one or more of: the pressure within the vessel and/or within the catheter (e.g., reverse-flow aspiration catheter); flow within the vessel and/or within the catheter; pressure and/or flow to the source of negative pressure, etc.
  • the communications sub-system may be a wireless communications sub-system and may transmit from the controller to a remote site (e.g., a remote processor and/or server, including a cloudbased server).
  • the controller may use the communications sub-system to access and/or receive input from one or more remote processors, including one or more libraries of optimum reverse flow rates based on vessel type, characteristic and/or location(s), including accessing a database or library of vessel optimum reverse flow rate values.
  • the controllers described herein may include or may access a memory for storing data, including data received from the one or more sensors, and/or processed (averaged, filtered, etc.) data from the one or more processors.
  • the memory may include instructions and/or data (e.g., vessel optimum reverse flow rate values) that may be accessed and, in some cases, modified by the controller.
  • the controller may generally include an output module for outputting (e.g., transmitting, storing and/or displaying) any of the sensed and/or derived data, including but not limited to sensed and/or derived pressure and/or flow rates.
  • the output module of the controller may be configured to present and/or format into a user interface any of this data.
  • the apparatuses described herein may include one or more outputs, such as monitors (screens, including touchscreens, LEDs, etc.), speakers, audio and graphical instructions to the operator etc.
  • the controller may coordinate outputs from and/or inputs to the system.
  • any of these methods and apparatuses may include one or more input modules.
  • the controller may coordinate, implement, store, and/or processes one or more inputs.
  • any of these methods and apparatuses may include an input module that is configured to receive ongoing or prompted input from a user (e.g., doctor, nurse, technician, etc.) entering information into or about the operation of the apparatus, including but not limited to the identity or characteristic (e.g., vessel optimum reverse flow rate value or a characteristic, including the name, size and/or duration of the vessel) that may allow estimation or selection of the vessel optimum reverse flow rate value.
  • a user e.g., doctor, nurse, technician, etc.
  • the identity or characteristic e.g., vessel optimum reverse flow rate value or a characteristic, including the name, size and/or duration of the vessel
  • the controller may be part of an apparatus that include the durable (e.g.., non- single-use/disposable) component s).
  • the controller may be configured to be self-contained, e.g., and may include one or more processors (e.g., microprocessors), one or more actuators for actuating the one or more valves or peristaltic pump heads (e.g., geared actuators, etc.).
  • the controller may include, in some examples, a printed circuit board assembly (PCB A).
  • PCB A printed circuit board assembly
  • the controllers described herein may include a power sub-system, including power regulation circuitry for controlling the power received (e.g., from a wall main, battery, etc.) and distributing power to the apparatus components as needed. Any of these apparatuses may include (as part of the controller or otherwise) a power source, such as a battery, and/or may be configured to be used with a source of external power.
  • the controller described herein may include, as part of an input-sub-system or otherwise, one or more inputs, including controls and control inputs.
  • these apparatuses may include a keyboard, mouse, touchscreen (which may also be part of the output subsystem), button, knob, slider, switch, etc. Any appropriate input or combination of inputs may be used.
  • the inputs may be remote from the system (e.g., part of an external device or system) that is accessed by the apparatus, including by the controller from a remote site as control input.
  • the controllers described herein may include one or more controllers specific to allow input or selection of the vessel optimum reverse flow rate value, either directly or indirectly, e.g., by entering or selecting the vessel location, type and/or characteristic (e.g., dimensions, such as diameter, volume, etc.) and deriving the vessel optimum reverse flow rate value.
  • any of these apparatuses may include an input (e.g., touchscreen, keyboard, switch, knob, etc.) that is configured to allow a user to enter or select an input value corresponding to the vessel optimum reverse flow rate value.
  • the input is configured to allow the user to select a vessel location from a menu of vessel locations.
  • a menu of vessel locations may include one or more of: an Ml segment of middle cerebral artery, an M2 segment of middle cerebral artery, an internal carotid artery, an Al segment of anterior cerebral artery, a basilar artery, and/or a Pl segment of posterior cerebral artery.
  • these apparatuses may include durable (e.g., re-usable) and single-use (e.g., disposable) portions that may be configured to interconnect.
  • the flow line, flow sensor, transducer protectors, and the first and second pressure-sensing sites may be part of a single-use flow line sub-assembly that is configured to be removably coupled to the durable assembly, which may include the valve or peristaltic pump mechanism, the controller, the first pressure sensor, the second pressure sensor, and the user display/interface components.
  • the controller, peristaltic pump, first pressure sensor and second pressure sensor may comprise a flow-reversal control sub-system configured to removably couple with the flow line, which may include a flow sensor and the first and second pressure-sensing sites.
  • the flow control may be a valve coupled to a source of negative pressure (suction), or in some embodiments, a peristaltic pump.
  • the valve may comprise any appropriate valve, such as (but not limited to) a pinch valve.
  • the flow-control valve may comprise a rotary needle valve.
  • the flow-control valve may generally be configured to allow selection of a number of (or a continuous valve within a range of) flow rates, e.g., from fully off (e.g., 0 ml/min) to the maximum reasonable flow (e.g., vessel optimum reverse flow rate value).
  • any of these apparatuses may include a flow control that is configured as a peristaltic pump that is in-line with the flow path. Peristaltic pump embodiments may be particularly useful for continuous blood return embodiments.
  • the first pressure-sensing sites may comprise a first pressure tap line in fluid communication with the flow line, and the second pressure-sensing site comprises a second pressure tap line in fluid communication with the flow line.
  • the pressure tap lines may include a junction (e.g., T-junction) off of the flow line.
  • these apparatuses may be configured so that the controller may limit the aspiration flow rate and pressure in the flow line in order to prevent collapse of the vessel when operated in a reverse-flow mode.
  • the controller may be configured to limit the flow through the flow line to be less than, e.g., 100 ml/min, 80 mL/min, etc. while maintaining a pressure at the proximal catheter no less than 0 mmHg.
  • any of these apparatuses may be configured to be operated in a second, e.g., full aspiration, mode in which a suction pressure (negative pressure) greater than what is needed for the optimum reverse flow reversal flow rate may be applied, e.g., to remove or aspirate embolic material if it has become corked in the catheter.
  • the apparatus may include a bypass to allow the application of high suction when selected manually (or in some examples automatically) in order to rapidly eliminate, or assist in eliminating, larger fragments or corked fragments of clot material.
  • pressures are reported as gauge pressures with 0 mmHg corresponding to atmospheric pressure.
  • any of these apparatuses may include a second flow line that is configured to apply a full aspiration (having a magnitude that is greater than that required for the optimal reverse flow rate).
  • the second flow line applying aspiration is not limited by the flow control (e.g., valve and/or peristaltic pump).
  • the second flow line may be in parallel with the flow line including the flow control and may bypass the flow control.
  • the second flow line may be configured as a bypass line to bypass the flowcontrol.
  • Any of these apparatuses may include a manual override, e.g., a manual override control/switch to override the modulation of pressure/flow and switch to full flow/aspiration from the catheter.
  • any appropriate catheter or arrangement of catheters may be used with or included as part of the vessel flow reversal apparatuses described herein.
  • these apparatuses may include one or more catheters configured to couple to the distal end of the flow line, the one or more catheters may be configured for insertion into the vessel.
  • the catheter(s) may be part of the disposable/single-use sub-system.
  • These apparatuses may be used with and/or may include a second aspiration catheter for applying aspiration to remove clot material positioned within the reverse flow catheter at a flow rate that is not limited to the vessel optimum reverse flow rate value or a maximum flow rate value of the reverse flow catheter.
  • the second catheter may be configured to be coaxially arranged relative to the reverse-flow aspiration catheter.
  • any of these apparatuses may include a second catheter (“full aspiration catheter”) sized to extend through a lumen of the reverse-flow aspiration catheter and to extend therethrough and out of a distal end of the first catheter.
  • the controller may be configured to reduce or suspend valve/pump action upon detecting an increase in aspiration pressure and/or decrease in flow through the flow line indicative of a collapse of the vessel.
  • vessel flow reversal systems may include: a flow line having a proximal end and a distal end; a flow control between the proximal end and the distal end of the flow line and configured to apply suction to the flow line; a first pressuresensing site distal to the flow control; a second pressure-sensing site proximal to the flow control; a flow-sensing site on the flow line; a first pressure sensor configured to couple to the first pressure-sensing site; a second pressure sensor configured to couple to the second pressure- sensing site; a flow sensor configured to couple to the flow-sensing site; and a controller comprising a processor configured to control operation of the flow control based on input from the first pressure sensor, the second pressure sensor, and the flow sensor to maintain an aspiration flow rate through the flow line within a range adapted to reverse arterial flow within a vessel in the neurovasculature, and to avoid collapse of the vessel during aspiration
  • the controller may be configured to control operation of the flow control based on a control algorithm.
  • the control algorithm may incorporate the input from the first pressure sensor, the second pressure sensor, the flow sensor, and one or more of a state of the flow control, a flow coefficient curve of the valve, a position of the flow control, a minimum allowable pressure, a maximum allowable pressure, a flow ramp rate, and a vessel optimum reverse flow rate value.
  • the control algorithm incorporates the input from the first pressure sensor, the second pressure sensor, the flow sensor, and a rotation speed of the flow control when the flow control comprises a peristaltic pump.
  • control algorithm may change the optimum reverse flow rate value and the flow ramp rate based on detecting one or more of changes in pressure at the first and second pressure sensors, a pressure gradient between the first and second pressure sensors (AP), flow meter input, and the flow characterization of the flow control.
  • the flow control may comprise a peristaltic pump and the flow characterization of the flow control may comprise a speed of the peristaltic pump.
  • the flow characterization comprises a flow coefficient curve.
  • the flow line, flow sensor, and the first and second pressure-sensing sites may comprise a single-use flow line sub-assembly further comprising a stopcock and an aspiration fitting, wherein the flow line sub-assembly is configured to be removably coupled to the controller, flow-control valve or peristaltic pump, first pressure sensor and second pressure sensor.
  • the controller, flow control, first pressure sensor and second pressure sensor may comprise a flowreversal control sub-system configured to removably couple with the flow line, and the first and second pressure-sensing sites.
  • the flow control may comprise a pinch valve.
  • the flow control may comprise a peristaltic pump.
  • the proximal end of the flow line may be configured to be coupled to a venous sheath.
  • the proximal end of the flow line may be configured to be opened to atmosphere.
  • the first pressure-sensing site may comprise a first pressure tap line in fluid communication with the flow line, and the second pressure-sensing site comprises a second pressure tap line in fluid communication with the flow line.
  • the controller may be configured to limit the aspiration flow rate to less than 250 mL/min.
  • any of these systems may include a catheter configured to couple to the distal end of the flow line, the catheter further configured for insertion into the vessel, wherein the catheter further includes an inflatable balloon at least around a distal end of the catheter to enable one or more of: (i) contouring the catheter to the blood vessel, (ii) anterograde flow arrest beyond the outside of the catheter, and (iii) anterograde arrest of emboli beyond the outside of the catheter.
  • the system may include a second member sized to extend through a lumen of the first catheter and to extend therethrough and out of a distal end of the first catheter.
  • the controller may be configured to reduce or suspend aspiration upon detecting changes in flow and/or aspiration pressure at the first pressure sensing site, the second pressuresensing site, and/or the flow sensor indicative of a collapse of the vessel. Any of these systems may include an output for indicating at least one of flow and/or pressure corresponding to flow in the flow line and/or pressure at a catheter coupled to the flow line in real time.
  • the output may include a user interface configured to display the flow and/or pressure corresponding to the vessel in real time and provide visual and/or audio warnings if flow reversal stops or slows.
  • the system may include one or more sealing connectors configured to minimize a lip or narrowing region caused by a male component of traditional luer connectors to prevent clots from becoming lodged within the flow reversal system and causing flow obstruction. Any of these systems may include a three-way stopcock at a distal end of the flow line that is configured to couple to a syringe for delivery of a contrast material.
  • Any of these systems may include a second flow line configured to apply a full-vacuum aspiration, wherein the magnitude of the full-vacuum aspiration exceeds that required for the vessel optimum reverse flow rate.
  • the second flow line may be configured as a bypass line configured to bypass the flow control.
  • any of these systems may include a manual override switch to override the modulation of the flow control and switch to full aspiration / high flow.
  • the controller is configured to detect and adapt to vessel collapse, based on a change in pressure (AP) between readings of the first pressure sensor and the second pressure sensor, or based on the flow sensor, such that when AP or flow approaches 0 the controller performs one or more of: (i) stopping flow control, (ii) implementing a minimum flow rate, and (iii) scaling to a new flow rate setpoint based on a percentage of a current or previous flow rate setpoint, further wherein the system either indicates an error and stops flow by the flow control, or triggers a warning, if the minimum flow rate cannot be implemented.
  • AP change in pressure
  • the controller may be configured to detect and adapt to a disruption in the aspiration flow rate by causing the flow control to adjust the flow to reach one or more of: (i) a minimum aspiration flow rate, and (ii) a desired flow rate.
  • the system may set a minimum aspiration flow rate close to 0 when the vessel has limited collateral vessels to provide a source of blood.
  • the flow control may comprise a peristaltic pump comprising a backing arch geometry, motion control algorithm, and a plurality of rollers having a size configured to limit peak-to-peak pressure and flow ripple.
  • the flow line comprises an elastomeric flow line configured to be held in a stretched condition on a backing arch before the backing arch is locked into position against a pump head.
  • a vessel flow reversal system may include: a flow line having a proximal end and a distal end; a peristaltic pump coupled to the flow line between the proximal end and the distal end; a first pressure sensor configured to sense pressure distal to the peristaltic pump; a second pressure sensor configured to sense pressure proximal to the peristaltic pump; a flow sensor configured to sense pressure in the flow line; and a controller comprising a processor configured to control operation of the peristaltic pump based on input from the first pressure sensor, the second pressure sensor, and the flow sensor to maintain an aspiration flow rate through the flow line within a range adapted to reverse arterial flow within a vessel in the neurovasculature, and to avoid collapse of the vessel during aspiration when the flow line is in communication with the vessel.
  • a method of reversing flow in a blood vessel may include: positioning a distal end of a reverseflow catheter proximal to embolic material within a vessel in the neurovasculature, wherein the reverse-flow catheter is coupled to a distal end of a flow line of a vessel flow reversal system including a flow control coupled to the flow line, a flow sensing site on the flow line, a first pressure-sensing site distal to the flow control, and a second pressure-sensing site proximal to the flow control; sensing a pressure at the first pressure-sensing site and the second pressure-sensing site; sensing flow at the flow sensing site; reversing flow within the vessel up to a predetermined flow rate and/or pressure limit by applying aspiration from the reverse-flow catheter by controlling the flow control based on the pressure sensed at the first pressure-sensing site, pressure sensed the second
  • Controlling the flow control may comprise controlling operation of a peristaltic pump.
  • controlling the flow control comprises adjusting a valve coupled to a source of suction.
  • the predetermined flow rate and/or pressure limit may be dependent on a position and/or size of the vessel and/or a size of the catheters being used.
  • Any of these methods may include receiving or determining the predetermined flow rate and/or pressure limit, wherein the predetermined flow rate comprises a vessel optimum reverse flow rate value corresponding to the position and/or size of the vessel and/or size of the catheters being used. Any of these methods may include determining the predetermined flow rate and/or pressure limit, based on pressure sensed at the first and/or second pressure-sensing site and/or the flow sensed at the flow sensing site during passive flow of blood through the flow line from the patient’s arterial pressure following inflation of a balloon around the distal end of the reverse-flow catheter prior to engaging the flow control.
  • a method may include calculating the predetermined optimum reverse flow rate by multiplying the passive blood flow rate through the flow line by a predetermined factor. Any of these methods may include receiving or determining a flow ramp rate for reaching the predetermined flow rate and/or pressure limit, wherein adjusting the aspiration comprises adjusting the flow rate value and flow ramp rate in response to changes to the sensed pressure and a state of the flow control, wherein the adjusted flow rate value does not exceed the predetermined flow rate.
  • a method of reversing flow in a blood vessel may include: positioning a distal end of a reverse-flow aspiration catheter proximal to embolic material within a vessel of a patient’s neurovasculature; receiving or determining a vessel optimum reverse flow rate value within a vessel flow reversal system, wherein the vessel optimum reverse flow rate value corresponds to the vessel; receiving or determining a flow ramp rate for reaching the vessel optimum reverse flow rate value for the vessel; reversing flow within the vessel by applying aspiration from the reverse-flow aspiration catheter that is coupled to a vessel flow reversal system, by controlling a flow control to reach the vessel optimum reverse flow rate according to the flow ramp rate; and preventing collapse of the vessel by adjusting the flow control in response to changes to a sensed pressure at a first pressure-sensing site distal to the flow control, and at a second pressure-sensing site proximal to the flow control, wherein the adjusted flow rate value
  • the method may include monitoring the aspiration flow rate applied through the reverse-flow aspiration catheter.
  • receiving or determining the vessel optimum reverse flow rate may comprise receiving the vessel optimum reverse flow rate value from a user input to the vessel flow reversal system.
  • Receiving may comprise receiving an indication of the size and/or position of the vessel within which the distal end of the reverse-flow aspiration catheter is positioned and/or the sizes of the catheters being used.
  • Preventing collapse of the vessel may comprise automatically shutting off or reducing aspiration when the aspiration flow rate exceeds the vessel optimum reverse flow rate value.
  • Any of these methods may include bringing the embolic material in contact with or near the distal end of the flow-reversal catheter via the applied aspiration, and applying suction from a second catheter to capture all or a portion of the embolic material into the flow-reversal catheter.
  • the suction applied from the second catheter may result in flow of a magnitude that is greater than a magnitude of the vessel optimum reverse flow rate value, further wherein the magnitude of the aspiration is increased up to a maximum allowable flow.
  • the second catheter may be coaxial with the reverse-flow aspiration catheter. In some examples the second catheter is located in a different region of the patient’s neurovasculature.
  • Preventing collapse of the vessel may comprise adjusting the flow control by regulating a valve of the vessel flow reversal system that is connected between a source of negative pressure and the proximal end of the reverse-flow aspiration catheter.
  • Preventing collapse of the vessel may comprise adjusting the flow control by regulating the speed of a peristaltic pump which acts on the flow line, and returning blood removed by the aspiration catheter to the body via a venous cannula or sheath after passing through a blood filter.
  • Adjusting the flow control may comprise sensing pressure from a source of negative pressure proximal to the flow control, sensing the pressure distal to the flow control, and adjusting the flow control based on the vessel optimum reverse flow rate value.
  • Positioning may comprise positioning within one of: an Ml segment of middle cerebral artery, an M2 segment of middle cerebral artery, an internal carotid artery, an external carotid artery, a common carotid artery, an Al segment of anterior cerebral artery, a basilar artery, and/or a Pl segment of posterior cerebral artery.
  • flow line sub-assembly systems for a flow-reversal apparatus that may include: a flow line having a proximal end and a distal end, wherein the flow line is configured to couple to flow control comprising a source of suction at a flow control site; a first pressure-sensing site on the flow line distal to the flow control site; a second pressure-sensing site proximal to the flow control site; a flow sensor configured to sense pressure in the flow line; a stopcock; and an aspiration fitting, wherein the flow line sub-assembly is configured to be removably coupled to a controller configured to control operation of the source of suction based on input from the first pressuresensing site, the second pressure-sensing site, and the flow sensor to maintain an aspiration flow rate through the flow line within a range adapted to reverse arterial flow within a vessel in
  • a single-use flow line sub-assembly system may include a valve on the flow line configured to couple to the source or pressure.
  • the system includes an output coupled to the flow sensor and configured to couple to the controller.
  • a vessel flow reversal system may include: a peristaltic pump configured to apply suction to a flow line; a first pressure sensor configured to couple to a first pressure-sensing site on the flow line; a second pressure sensor configured to couple to a second pressure-sensing site on the flow line; and a controller comprising one or more processors configured to control operation of the peristaltic pump based on input from the first pressure sensor, the second pressure sensor, and a flow sensor sensing flow from the flow line, to maintain an aspiration flow rate through the flow line within a range adapted to reverse arterial flow within a vessel in the neurovasculature, and to avoid collapse of the vessel during aspiration when the flow line is in communication with the vessel.
  • the controller may be configured to incorporate the input from the first pressure sensor, the second pressure sensor, the flow sensor, and one or more of: a state of the flow control, a flow coefficient curve of the valve, a rotational speed of the peristaltic pump, a minimum allowable pressure, a maximum allowable pressure, a flow ramp rate, and a vessel optimum reverse flow rate value.
  • the controller may be configured to change the vessel optimum reverse flow rate value and the flow ramp rate based on detecting one or more of: changes in pressure at the first and second pressure sensors, a pressure gradient between the first and second pressure sensors (AP), flow meter input, and the flow characterization of the flow control.
  • the flow characterization may comprise a flow coefficient curve. Any of these systems may include an input configured to allow a user to enter or select an input value corresponding to the vessel optimum reverse flow rate value, wherein the system further calculates a flow ramp rate setpoint to reach the input value corresponding to the vessel optimum reverse flow rate value.
  • the input may be configured to allow the user to select a vessel location from a menu of vessel locations and input the sizes of the catheters being used.
  • the menu of vessel locations may include one or more of: an Ml segment of middle cerebral artery, an M2 segment of middle cerebral artery, an internal carotid or common carotid artery, an Al segment of anterior cerebral artery, a basilar artery, and/or a Pl segment of posterior cerebral artery.
  • these methods and apparatuses may provide output to the user of the proximal catheter pressure and/or flow rates within the catheter and/or within the flow line (or other region(s) of the apparatus) during operation. This output may allow the user to adjust (manually or semi-automatically) the operation of the system, including the flow rate of aspiration being applied to reverse the flow and/or to remove (aspirate) material.
  • an output e.g., display
  • a graph, chart or the like may be shown or selected for display.
  • the output comprises a user interface configured to display the flow and/or pressure corresponding to the catheter.
  • a simplified output e.g., one or more LEDs or other lights
  • these apparatuses and methods may be configured for use with visualization of the neurovasculature, including fluoroscopy, ultrasound, or any other appropriate visualization technique.
  • the controller may be configured to receive input from the visualized surgical field, or an intermediary apparatus (software, hardware and/or firmware) processing such visualized information.
  • the controller may receive input indicating the location, characteristics and/or identity of the vessel from such visualization data, including the location of a radiopaque marker identifying the reverse-flow aspiration catheter within the neurovascul ature .
  • any of these apparatuses may be configured to allow injection of a visualizing material (e.g., contrast) into or within the neurovasculature, including out of the reverse-flow aspiration catheter.
  • a visualizing material e.g., contrast
  • any of these apparatuses may include a valve (e.g., a three-way stopcock or the like) at a distal end of the flow line that is configured to couple to a syringe for delivery of a contrast material and/or a therapeutic material.
  • these apparatuses may include or be integrated with a source of negative pressure, including a vacuum pump, manifold, pressure reservoir, etc.
  • the apparatus may be configured to connect to a source of negative pressure from the wall.
  • the controller may regulate the applied source of negative pressure to maintain the pressure within the range to achieve the optimum reverse flow rate for the relevant vessel.
  • apparatuses that meter flow with a positive displacement peristaltic action of rollers mounted to a rotating pump head such that the rollers squeeze down on an elastomeric flow line as the head rotates to push fluid from the distal to proximal side of the pump.
  • any of the flow lines described herein e.g., part of a single-use flow line subassembly
  • a vessel flow reversal system may include: a flow line having a proximal end and a distal end, wherein the proximal end is configured to couple to a venous access sheath or be open to atmosphere; a first pressure-sensing site distal of the pump head; a second pressure-sensing site proximal of the pump head; a first pressure sensor configured to couple to the first pressure-sensing site; a second pressure sensor configured to couple to the second pressure sensing site; a flow sensing site in the flow line, either distal or proximal the pump head; a flow sensor configured to couple to the flow sensing site; a pump head with rollers that squeeze down on the elastomeric flow line; a controller configured to control the operation of the pump head based on input from pressure sensors and flow sensor, pump motor position and/or velocity, and a vessel optimum reverse flow rate value, wherein the pressure controller is configured to maintain an aspiration flow rate within a range
  • reversing flow in a blood vessel may include: positioning a distal end of a reverse-flow aspiration catheter proximal to an embolus within a vessel of a patient’s neurovasculature; receiving or determining a vessel optimum reverse flow rate value within a vessel flow reversal system, wherein the vessel optimum reverse flow rate value corresponds to the vessel; reversing flow within the vessel by applying aspiration from the proximal end of the reverse-flow aspiration catheter that is coupled to a vessel flow reversal system; preventing collapse of the vessel by controlling, in the vessel flow reversal system, the flow rate of the applied aspiration to prevent the flow rate from exceeding the vessel optimum reverse flow rate value.
  • embolus is not intended to be limiting and may be referred to herein as a “clot,” a “
  • any of these methods may include monitoring the aspiration flow rate applied through the reverse-flow aspiration catheter or flow line.
  • receiving or determining the vessel optimum reverse flow rate may comprise receiving the vessel optimum reverse flow rate value from a user input to the vessel flow reversal system.
  • receiving may comprise receiving an indication of the vessel within which the distal end of the reverse-flow aspiration catheter is positioned.
  • Preventing collapse of the vessel may include automatically shutting off aspiration/pump action when the flow rate or pressure suddenly change.
  • determining the optimum reverse flow rate may be achieved by allowing passive retrograde blood flow through a balloon guide catheter positioned within the neurovasculature, which is coupled to the flow line, after inflation of the balloon guide catheter balloon to arrest anterograde flow, and measuring the passive flow rate with a flow sensor in the flow line.
  • the optimum reverse flow rate applied may be a factor of the measured passive retrograde flow rate (e.g. 0.5 or 0.75 or 1.05 or 1.1 or 1.3 or 1.5 etc. times the passive flow rate).
  • Any of these methods may include applying suction/aspiration to achieve a flow rate greater than or less than the vessel optimum reverse flow rate value from a second catheter to capture all or a portion of the embolus.
  • the second catheter may be coaxial with the reverse-flow aspiration catheter.
  • the second catheter may be located in a different region of the patient’s neurovasculature.
  • preventing collapse of the vessel may include regulating a valve of the vessel flow reversal system that is connected between a source of negative pressure and the proximal end of the reverse-flow aspiration catheter.
  • controlling the flow rate that results from applied aspiration may include sensing pressure from the source of negative pressure proximal to the valve, sensing the pressure distal to the valve, and adjusting the valve based on the vessel optimum reverse flow rate value.
  • reversing flow in an blood vessel that include: positioning a distal end of a reverse-flow aspiration catheter proximal to an embolus within a vessel of a patient’s neurovasculature; sensing a pressure proximal to the embolus via a pressure sensor; reversing flow within the vessel by applying aspiration from the reverse-flow aspiration catheter that is coupled to a vessel flow reversal system, by controlling a valve of the vessel flow reversal system; and preventing collapse of the vessel and insufficient flow in the vessel by adjusting the valve in response to feedback based on changes to a sensed pressure.
  • preventing collapse of the vessel may be achieved by regulating flow with a peristaltic pump that is acting on the flow line attached to the proximal end of the reverseflow aspiration catheter. Similar to the above described example with a valve, controlling the flow rate may be achieved with a peristaltic pump by sensing pressure proximal and distal to the pump on the flow line, sensing flow distal and/or proximal to the pump in the flow line, and adjusting the speed of rotation of the pump head based on the vessel optimum reverse flow rate value and sensor data.
  • Any of these methods may include receiving or determining a vessel optimum reverse flow rate value within a vessel flow reversal system corresponding to the vessel; and receiving or determining a flow ramp rate for reaching the optimum reverse flow rate value for the vessel, wherein adjusting the aspiration comprises adjusting the flow rate value and flow ramp rate in response to changes to the sensed pressure and a position of the valve, wherein the adjusted flow rate value does not exceed the optimum reverse flow rate value.
  • a method of reversing flow in a blood vessel may include: positioning a distal end of a reverse-flow aspiration catheter proximal to an embolus within a vessel of a patient’s neurovasculature; sensing a pressure proximal to the embolus via a pressure sensor; receiving or determining a vessel optimum reverse flow rate value within a vessel flow reversal system, wherein the vessel optimum reverse flow rate value corresponds to the vessel; receiving or determining a flow ramp rate for reaching the optimum reverse flow rate value for the vessel; reversing flow within the vessel by applying aspiration from the reverse-flow aspiration catheter that is coupled to a vessel flow reversal system, by controlling a valve or pump of the system to reach the optimum reverse flow rate according to the flow ramp rate; and preventing collapse of the vessel and/or insufficient flow in the vessel by adjusting the flow rate value and flow ramp rate in response to changes to the sensed pressure and a position of the valve or rate of as
  • any of the apparatuses e.g., devices, systems, etc.
  • methods of performing remote thrombectomy in a blood vessel that include: positioning a distal end of an aspiration catheter proximal to an embolus within a vessel of a patient’s neurovasculature; sensing a pressure proximal to the embolus via a pressure sensor; reversing flow within the vessel by applying aspiration from the aspiration catheter, wherein the aspiration controlled via feedback to prevent collapse of the vessel; mobilizing the embolus towards the aspiration catheter via the reversed flow; modulating reverse flow rate in the vessel when the clot is proximate to the distal end of the aspiration catheter; and aspirating the embolus through the aspiration catheter.
  • Also described herein are methods of performing remote thrombectomy in a blood vessel may include , the method comprising: positioning a distal end of an aspiration catheter proximal to embolic material within a vessel of a patient’s neurovasculature, wherein the aspiration catheter is coupled to a distal end of a flow line of a vessel flow reversal system including a flow control coupled to the flow line, a first pressure-sensing site distal to the flowcontrol valve, a second pressure-sensing site proximal to the flow-control valve, and a flowsensing site in communication with the flow line; sensing a pressure at the first pressure-sensing site and the second pressure-sensing site and sensing flow at the flow-sensing site; reversing flow within the vessel by applying aspiration from the aspiration catheter, wherein the aspiration is controlled by controlling the peristaltic pump based on the pressure sensed at the first pressure- sensing site,
  • a method of performing remote thrombectomy in a blood vessel comprising: positioning a distal end of an aspiration catheter proximal to embolic material within a vessel of a patient’s neurovasculature; receiving or determining a vessel optimum reverse flow rate value within a vessel flow reversal system, wherein the vessel optimum reverse flow rate value corresponds to the vessel; receiving or determining a flow ramp rate for reaching the vessel optimum reverse flow rate value for the vessel; reversing flow within the vessel without collapsing the vessel by applying aspiration from the aspiration catheter that is coupled to the vessel flow reversal system, wherein the aspiration is controlled by controlling a flow control of the vessel flow reversal system to reach the vessel optimum reverse flow rate according to the flow ramp rate; mobilizing the embolic material towards the aspiration catheter via the reversed flow until it reaches the catheter tip; increasing reverse flow rate in the vessel past the vessel optimum reverse flow rate value; and aspirating the embolus
  • a method of performing remote thrombectomy in a blood vessel may include: positioning the distal end of an aspiration catheter proximal to an embolus within a vessel of the patient’s neurovasculature; sensing a pressure proximal to the embolus via a pressure sensor; receiving or determining an vessel optimum reverse flow rate value within a vessel flow reversal system, wherein the vessel optimum reverse flow rate value corresponds to the vessel; receiving or determining a flow ramp rate for reaching the optimum reverse flow rate value for the vessel; reversing flow within the vessel without collapsing the vessel by applying aspiration through the aspiration catheter that is coupled to the vessel flow reversal system, wherein the aspiration is based on controlling a valve or pump of the system to reach the optimum reverse flow rate at the flow ramp rate; mobilizing the embolus towards the aspiration catheter via the reversed flow; modulating reverse flow rate in the vessel past the optimum reverse flow rate value; and aspirating
  • FIGS. 1 A-1F are schematic illustrations of a reverse flow embolectomy procedure.
  • FIGS. 2A-2B are radiographic images depicting a catheter advanced into an occluded blood vessel with and without contrast dye injected.
  • FIG. 3 is a schematic of an exemplary flow reversal system.
  • FIG. 4 is a schematic of an exemplary flow reversal system with a syringe and vacuum pump.
  • FIG. 5 is a schematic of an exemplary flow reversal system with a bypass valve.
  • FIG. 6 is a schematic of an exemplary flow reversal system with a flow sensor.
  • FIG. 7 is a schematic of an exemplary disposable assembly with connections for a flow reversal system.
  • FIGS. 8A-8B is a schematic for a pinch valve in a flow reversal system.
  • FIG. 8C is a flow diagram for operation of a flow reversal system.
  • FIG. 9 is a schematic for a pinch valve disposal assembly.
  • FIG. 10 is a schematic for a durable assembly.
  • FIG. 11 is a schematic for a simplified display.
  • FIG. 12 is a graph displaying flow and pressure parameters.
  • FIG. 13 A is a graph displaying flow and pressure parameters in a vessel collapse scenario.
  • FIG. 13B is a graph displaying flow and pressure parameters in an aspiration/vacuum source disconnected scenario.
  • FIG. 13C is a graph displaying flow and pressure parameters for a flow reversal system response to avoid vessel collapse during a scenario in which a blood vessel lacks sufficient collateral blood vessels.
  • FIG. 14 is a flow rate table for various vessel locations.
  • FIG. 15 is a flow chart depicting one example of a method of reversing flow in an occluded blood vessel using an apparatus as described herein.
  • FIGS. 16A-16B is a flow chart depicting an example of a method for reversing flow embolectomy.
  • FIGS. 16C-16D is a flow chart depicting an example of a method for remote embolectomy.
  • FIGS. 17A-17B illustrate examples of one variation of a catheter sub-system (e.g., reverse-flow aspiration catheter and full aspiration catheter) that may be used with any of these apparatuses described herein.
  • a catheter sub-system e.g., reverse-flow aspiration catheter and full aspiration catheter
  • FIG. 19 illustrates a sealing connector which minimizes the lip.
  • FIGS. 22A-22C show examples of different peristaltic pump head configurations.
  • FIG. 23 A shows an example of how the flow line may be secured within a peristaltic pump flow reversal system.
  • FIG. 24 is a graph displaying flow and pressure parameters for a flow reversal system with minimal flow and pressure ripple.
  • Described herein are vessel flow reversal systems and apparatuses, including devices and systems.
  • these apparatuses include hardware, software and/or firmware to control the flow of blood from a reverse-flow catheter that may be part of the apparatus or may be coupled to the apparatus.
  • the apparatus may prevent collapse within the vessel into which the catheter is positioned by regulating, using feedback from one or more sensors included as part of the system that monitor and regulate the pressure based on one or more characteristics of the vessel, such as the type (e.g., the type of the vessel), location, and/or size of the vessel.
  • these apparatuses and methods may maintain the application of a relatively low negative pressure to produce a reversed flow within the vessel by maintaining the pressure within a vessel-specific range in order to prevent collapse of the vessel.
  • the applied negative pressure may be maintained at a very low level using a low-flow flow-control valve.
  • the flow-control valve may be coupled to the catheter through a flow line and may be dynamically controlled based on input from one or more sensors (e.g., pressure and/or flow sensors) and based one or more characteristics of the vessel.
  • the methods and apparatuses described herein may maintain application of the low negative pressure to induce a safe reverse flow rate by directly or indirectly controlling a suction pump coupled to the fluid line and to the catheter.
  • These methods and apparatuses may be used as part of any procedure in which safe flow reversal would be beneficial, particularly (but not exclusively) within the neurovasculature.
  • a vessel flow reversal system including: a flow line having a proximal end and a distal end, in which the proximal end is configured to couple to a source of suction; a flow-control valve coupled to the flow line between the proximal end and the distal end; a first pressure-sensing site distal to the flow-control valve; a second pressuresensing site proximal to the flow-control valve; and a first pressure sensor configured to couple to the first pressure-sensing site; a second pressure sensor configured to couple to the second pressure-sensing site; and a controller comprising a processor configured to control the operation of the flow-control valve based on input from the first pressure sensor, the second pressure sensor, the position of the valve, flow coefficient curve of the valve, negative feedback control algorithm, a minimum or maximum allowable pressure, a flow ramp rate, and an vessel optimum reverse flow rate value, to maintain an aspiration flow rate through the flow line
  • an input is configured to allow a user to enter or select an input value corresponding to the vessel optimum reverse flow rate value, in which the system further calculates a flow ramp rate setpoint to reach the input value corresponding to the vessel optimum reverse flow rate value.
  • the input is configured to allow the user to select a vessel location from a menu of vessel locations.
  • the menu of vessel locations includes one or more of: an Ml segment of middle cerebral artery, an M2 segment of middle cerebral artery, an internal carotid artery, a common carotid artery, an external carotid artery, an Al segment of anterior cerebral artery, a basilar artery, and/or a Pl segment of posterior cerebral artery.
  • the stopcock, flow line, the first and second pressure-sensing sites, and the suction fitting comprises a single-use flow line sub-assembly configured to be removably coupled to the controller, pinch valve, first pressure sensor and second pressure sensor.
  • the controller, pinch valve, first pressure sensor and second pressure sensor includes a flow-reversal control sub-system configured to removably couple with the flow line, and the first and second pressure-sensing sites.
  • the flow-control valve includes a pinch valve, in which the pinch valve is part of a durable assembly.
  • the flow-control valve includes a rotary needle valve, in which the needle valve is part of a disposable assembly.
  • the first pressure-sensing site includes a first pressure tap line in fluid communication with the flow line
  • the second pressure-sensing site includes a second pressure tap line in fluid communication with the flow line
  • the controller is configured to limit the aspiration flow rate to less than 250 mL/min.
  • a catheter is configured to couple to the distal end of the flow line, the catheter further configured for insertion into the vessel, in which the catheter further includes an inflatable balloon at least around a distal end of the catheter to enable one or more of: (i) contouring the catheter to the blood vessel, (ii) anterograde flow arrest beyond the outside of the catheter, and (iii) anterograde arrest of emboli beyond the outside of the catheter.
  • the controller is configured to reduce or suspend vacuum pressure at the proximal catheter upon detecting a decrease in pressure at the distal pressure sensing site and/or decrease in flow through the flow line indicative of impending collapse of the vessel.
  • the output indicates proximal catheter pressure as a hemodynamic trace over time.
  • the output includes a user interface configured to display the flow and/or pressure corresponding to the vessel.
  • a three-way stopcock or RHV at a distal end of the flow line that is configured to couple to a syringe for delivery of a contrast material.
  • a second flow line configured to apply a fullvacuum aspiration, in which a magnitude of the full-vacuum aspiration is greater than a magnitude of the vessel optimum reverse flow rate value.
  • the second flow line is configured as a bypass line configured to bypass the flow-control valve or peristaltic pump.
  • the system e.g., the controller of the system, may be configured to detect and adapt to vessel collapse, based on a change in pressure (AP) between readings of the first pressure sensor and the second pressure sensor, such that when the first (distal) pressure sensor approaches 0 the controller performs one or more of: (i) stopping flow, (ii) implementing a minimum flow rate, and (iii) scaling to a new flow rate setpoint based on a percentage of a current or previous flow rate setpoint, further wherein the system indicates an error and closes the valve if the minimum flow rate cannot be implemented.
  • the system may set a minimum flow rate close to or at 0 when the neurovasculature is unable to support higher reverse flows.
  • the controller may be configured to detect and adapt to a disruption in the aspiration flow rate based on readings from the first and second pressure sensors by opening the flow-control valve to reach one or more of: (i) a desired reverse flow rate, or (ii) a minimum reverse flow rate.
  • the system detects and adapts to vessel collapse, in which vessel collapse is detected based on a drop in pressure based on readings of the first pressure sensor and the second pressure sensor, in which adapting to vessel collapse includes one or more of: (i) stopping flow, (ii) implementing a minimum flow rate, and (iii) scaling to a new flow rate setpoint based on a percentage of a current or previous flow rate setpoint, in which the system indicates an error and closes the valve if the minimum flow rate cannot be implemented.
  • the system detects and adapts to a disruption in the aspiration flow rate based on readings from a flow sensor, in which the system opens the flowcontrol valve to reach one or more of: (i) the aspiration flow rate, and (ii) a desired flow rate.
  • the system sets a minimum flow rate close to or at 0 when the neurovasculature is unable to support higher flow (e.g., relatively lacks collateral vessels).
  • removing the injected contrast 112 via suction using the syringe or other source of aspiration 114 creates a reverse flow and enables the physician to visually confirm flow reversal; as described herein, the system may control the negative pressure (suction) applied to remove the contrast in order to prevent arterial collapse.
  • the apparatus may prevent the suction from exceeding defined limits that may be specific to the vessel 102, based on a vessel flow rate value specific to the vessel and implemented by the apparatus.
  • the application of reverse flow may be controlled by a valve 116.
  • Reverse flow 115 in blood vessel 102 may move (or assist in moving) clot fragments and/or microemboli 111 into catheter 104 upon withdrawal 109(b) of the smaller caliber aspiration catheter 109 during a typical primary contact aspiration embolectomy maneuver. This may provide for safer and more efficient embolectomy by avoiding embolization of small mobile emboli to the downstream territory.
  • Valve 116 may be opened 118 to generate reverse flow 115, for example via control interface 122 which may set a desired reverse low flow rate for a given blood vessel (e.g., the vessel optimum reverse flow rate value).
  • Flow sensor 120 may also provide feedback regarding real-time flow rates in blood vessel 102.
  • a relatively high level of aspiration e.g., greater than the vessel optimum reverse flow rate value
  • This may be accomplished by switching the reverse flow suction to a high-flow aspiration and/or by applying high-flow aspiration from a second catheter.
  • FIG. ID depicts a high-flow suction/aspiration step 100D.
  • aspiration 117 of clot 108 may be achieved via a bypass valve/suction control 124.
  • aspiration 117 may be implemented, for example, by pressing a button on the control interface 122 which opens the valve 116 to allow high-flow suction.
  • FIG. IE illustrates a clot clearing step 100E in which clot 108, or clot 108 and microemboli 111 are removed from blood vessel 102 via catheter 104, for example pursuant to aspiration 117.
  • clot 108 may be cleared via mechanical or other means.
  • FIG IF the system is shown performing “remote thrombectomy” 100F.
  • the clot 108 is pulled back from its distal location to the tip of catheter 104 by the reversed flow 115, without the use of an additional aspiration catheter or thrombectomy device.
  • a change in pressure and flow is sensed and displayed on user interface 122.
  • the physician may then request high-flow suction 117 from the system and facilitate ingestion of the embolus 108 through catheter 104.
  • the operator can then select to change from high-flow aspiration back to active control of reverse flow on interface 122, in order to ingest into catheter 104 any microemboli that may have been generated during the thrombectomy maneuver.
  • the switching from active control of reverse flow to high-flow aspiration and back in this example may be automated.
  • performing remote thrombectomy may not be feasible, such as when there is high friction between a clot and vessel wall that may occur if a certain amount of time has passed since the clot was formed or lodged in the vessel.
  • FIGS. 1G and 1H schematically illustrate two examples of systems that may be configured to perform the methods described above in FIGS. 1 A-1F.
  • FIG. 1G shows an example of a vessel flow reversal system that is configured to provide blood return to the patient (e.g., the ‘blood sink’ connects to a vein).
  • the system is configured to couple to the body (e.g., an artery) through, e.g., a ballon guide catheter or aspiration catheter.
  • the system include a flow line sub-assembly that may include a flow line with a first pressure-sensing site and a second pressure-sensing site and a flow-sensing site on the flow line.
  • the system also includes a controller having one or more processors that are configured to control operation of the flow control (e.g., peristaltic pump and/or valve, e.g., pinch valve, coupled to source of negative pressure) based on input from the first pressure sensor, the second pressure sensor, and the flow sensor to maintain an aspiration flow rate through the flow line within a range adapted to reverse arterial flow within a vessel, and to avoid collapse of the vessel during aspiration when the flow line is in communication with the vessel.
  • the flow control e.g., peristaltic pump and/or valve, e.g., pinch valve, coupled to source of negative pressure
  • 1G may return the blood that has been removed (after filtering) to the patient, either continuously or discretely while removing blood, using the peristaltic pump.
  • the blood sink may be a storage container (e.g., canister). This blood may be manually returned to the patient in some examples.
  • the aspirated blood may be filtered.
  • One or more filters may be included and may be poisoned anywhere along the flow circuit.
  • FIGS. 2A-2B are radiographic images depicting catheters advanced towards an occluded M2 middle cerebral artery with and without contrast dye injected 200/250.
  • contrast dye is injected to visualize vascular anatomy 200, for example via a syringe.
  • Injected contrast dye highlights the location of catheter 202 (with its tip either occlusive or nearocclusive to antegrade flow) in the Ml segment of the middle cerebral artery, and a smaller caliber aspiration catheter 208 passing through catheter 202 to have its tip in contact with an embolus in the M2 branch of the middle cerebral artery 204.
  • FIG. 1A-2B are radiographic images depicting catheters advanced towards an occluded M2 middle cerebral artery with and without contrast dye injected 200/250.
  • contrast dye is injected to visualize vascular anatomy 200, for example via a syringe.
  • Injected contrast dye highlights the location of catheter 202 (with its tip either occlusive or nearocclusive to antegrade flow) in the M
  • the contrast and then blood have been aspirated out creating a reverse flow environment that assists with removing the embolus from the M2 branch during a typical contact aspiration embolectomy maneuver with catheter 208 (involving separate aspiration through catheter 208, and withdrawal of catheter 208 through catheter 202).
  • the reverse flow environment allows for ingestion of microemboli which are generated during the embolectomy maneuver into catheter 202.
  • the flow is maintained within a vessel optimum reverse flow range for this vessel, preventing vessel collapse and thereby optimizing flow reversal.
  • the reverse flow environment and capture of the embolic fragments may be achieved by other means, including a valve, vacuum, or pump running concurrently with aspiration of the contrast.
  • a high flow aspiration/ suction may be implemented following this step to clear clot of M2 branch occlusion 204 from the blood vessel and/or catheter.
  • the high-flow catheter may be concentric with the low-flow (reverse flow) catheter, or it may be located in a different region of the vessel 208 (or an adjacent vessel).
  • High flow (aspiration) may be activated within the reverse flow catheter by monitoring (e.g., under fluoroscopy) the position of the clot material and triggered when the clot is sufficiently near to the distal tip of the reverse flow catheter so that clot material may be rapidly removed without collapsing the vessel. Following capture, the high-flow aspiration may be turned off, and reverse flow control may be maintained or discontinued.
  • FIG. 3 is a schematic of an exemplary flow reversal apparatus (e.g., system) 300.
  • the apparatus includes a durable assembly 304 which may include hardware, software and/or firmware for controlling the application of the pressure to induce reverse flow within the vessel.
  • the apparatus may also include a display (e.g., display screen) for visualizing and controlling flow and pressure with a blood vessel.
  • Durable assembly 304 may include control circuitry, e.g., one or more processors, power control circuitry, pressure sensors 310, motor 312, flow adjustment mechanism (e.g., selector) 314, memory, communication (e.g., wireless) control circuitry, etc.
  • the durable assembly may include a housing enclosing all or some of these components.
  • the durable assembly may be coupled to a disposable assembly including tubing 302, valve 305, suction fitting, T-shaped connectors 308 for connection to pressure sensors, and a rotating haemostatic valve and stopcock 306 configured to connect to a catheter for performing embolectomy.
  • the disposable assembly is connected to flow reversal system 300 by a user at three points including a valve stem, catheter pressure sensor, and vacuum pressure sensor.
  • a valve 305 may be supplied open before use, and a user may flush all lines prior to connecting valve 305 to the durable assembly.
  • valve 305 is a single-use control valve with custom features to interface with a motor in the durable assembly.
  • the RHV and stopcock 306 may be a 3-way stopcock permanently bonded to the flow line.
  • FIG. 4 is a schematic of an exemplary flow reversal apparatus (e.g., system) with a syringe and vacuum 400.
  • various connections to tubing 402 of durable assembly may include: a flow reversal catheter 406 of various sizes (e.g., catheters having inner diameters of 0.088”, 0.070”, 0.068”, 0.054”), a syringe 408 for contrast injections, as according to certain examples, the flow reversal system does not provide pressure measurements within the catheter, and a vacuum source 410 for embolus aspiration, which according to certain embodiments may be a standard vacuum source with standard 2-port canister.
  • the primary vacuum source 410 can be an active source of aspiration such as an aspiration pump, a regular or locking syringe, a hand-held aspirator, hospital suction, or the like, configured to draw suction through the working lumen.
  • the vacuum source 410 is a locking syringe (for example a VacLok Syringe). The user can pull the plunger on the syringe back into a locked position while connection to the flow line and control system 404 will automatically adjust the valve to maintain reverse flow rate. During the procedure if the distal tip of the reverse flow catheter is near or at the face of the occlusion, the user may tell system 404 to fully open valve 405 to the locking aspiration syringe enabling rapid flow of clot material.
  • the embolus may be captured by the reverse flow catheter such that at least a portion of the embolus is contained within the lumen of the catheter while another portion of the embolus remains outside the lumen of the catheter. Capture of the embolus where a portion of the embolus remains outside the catheter lumen can be referred to herein as “corked” or “corking” the catheter. At times a corked catheter may mean that full evacuation of the embolus into the proximal canister is not possible and instead the catheter is withdrawn carrying the corked embolus with it.
  • the embolus may be captured by the catheter such that a majority of the embolus is contained within the catheter lumen while a small portion or no portion of the embolus remains outside the catheter lumen.
  • Capture of the embolus where a majority of the embolus is contained within the lumen can be referred to herein as being “engulfed” by the catheter.
  • An embolus that is engulfed in the catheter lumen may still progress towards the proximal canister under aspiration pressure or the engulfed embolus may move only minimally within the catheter lumen and ultimately a physician withdraws the catheter in order to remove the embolus from the patient.
  • FIG. 5 is a schematic of an exemplary flow reversal system with a bypass valve 500. As shown here, bypass valve 520 may be opened for full vacuum suction when desired, for example when a larger embolus has been “captured” by the distal tip of the flow reversal catheter.
  • FIG. 6 is a schematic of an exemplary flow reversal system with a flow sensor 600.
  • a flow sensor 602 which according to certain embodiments may be a clamp-on or inline style flow sensor.
  • Flow sensor 602 is configured to measure real-time flow rates in a target blood vessel and may interface with durable assembly 604 to display this information to a user.
  • FIG. 7 is a schematic of an exemplary disposable assembly with connections for a flow reversal system 700 similar to FIG. 3. As shown here, there are T-shaped connectors 702 for connection to pressure sensors near valve 705. According to certain embodiments, valve 705 is a single-use control valve with custom features to interface with a motor in the durable assembly. Stopcock 703 may be a 3-way stopcock permanently bonded to a distal vacuum line. According to certain embodiments, suction fitting 707 may be permanently bonded to the proximal flow line.
  • FIGS. 8A-8B is a schematic for a pinch valve in a flow reversal system 800.
  • a cam action pinch valve 802 in an open configuration 802A.
  • the pinch valve may rotate about an axis 804.
  • the cam action pinch valve may be rotated by as much as 180 degrees to pinch off flow 802B. According to certain embodiments, this action may be fast enough so that the flow reversal system can rapidly open for full vacuum without the need to use a bypass valve.
  • FIG. 8C is a flow diagram for operation of a flow reversal system 850.
  • the various steps 852-882 may be automated and/or performed in varying order. As show here, operation may begin with a user selecting a target vessel 852, and in some the user concurrently turning a flow rate adjust knob 854. Next, the system looks up a flow rate setpoint (FRSP) from system memory 856. Once the system sets the FRSP 858, the system calculates a flow ramp rate setpoint (FRRSP) 860 and flow rate (FR) and flow ramp rate (FRR) control loops drive system 862 via cascade controller. Concurrently, alternatively, or at another point in time, the system measures a first pressure Pl 868 and a second pressure P2 864. The system then calculates a difference in pressure AP 870.
  • FRSP flow rate setpoint
  • FR flow ramp rate setpoint
  • FR flow rate
  • FRR flow ramp rate
  • the system measures a pinch valve position 872, followed by the system looking up a flow coefficient from system memory 874.
  • the system calculates FR and FRR 876, which may also result in FR and FRR control loops driving system 862.
  • the system may query as to whether vessel collapse is imminent (VCI) 878. If it is determined that vessel collapse is indeed imminent 880, then the system may scale a new FRSP as a percentage of the previous FRSP 882, and the system may set (the new) FRSP 858.
  • VCI vessel collapse is imminent
  • FIG. 9 is a schematic for a pinch valve disposal single use tubing assembly 900.
  • the pinch valve disposal assembly 900 may be of a simpler design and lack a valve on the disposable assembly and the tubing between the T-fittings 902 can be slipped into the pinch valve 802.
  • the T-fittings 902 may be of different sizes or configurations to prevent improper connection of the disposable assembly 900 to the durable assembly 800.
  • FIG. 10 is a schematic for a durable assembly 1000.
  • durable assembly 1000 includes a touch screen which may display menu window 1004 for a user to select various commands or view displays include various blood vessels of interest, catheter sizes, flow and pressure graphs, device information, etc.
  • the screen may also display a graph 1006 for real-time traces of pressure on the catheter side of the valve and flow through the valve, as well as flow rate setpoint, target vessel for the distal end of the reverse flow catheter, pressure on the vacuum pump side of the valve, and total fluid transferred.
  • Selection knob 1011 may be manipulated to change a flow setpoint.
  • manipulating selection knob 1011 may toggle between menu options in a menu view that may be accessed via display menu window 1004.
  • PCBA printed circuit board assembly
  • SBC single board computer
  • Pressure sensors 1012 may be calibrated and of a durable quality to provide pressure readings, and kept from exposure to blood by transducer protectors.
  • Durable assembly 1000 may also include a stepper or servo motor with position encoder 1010 and be powered via hospital main 1016.
  • the durable assembly may include a power train with gears, sprockets, pulleys, chains and/or belts. According to certain embodiments, durable assembly 1000 may be powered by a rechargeable battery pack.
  • FIG. 11 is a schematic for a simplified display 1100.
  • the durable assembly may have a simplified display 1100 for ease-of-use or for simpler embolectomy procedures, including LED flow indicator 1108 which may indicate via lights or other indicators when pressure and/or flow rates are reaching minimum or maximum limits.
  • a simplified character display screen 1110 may display abbreviated or more concise data points including catheter pressure, vacuum pressure, flow setpoint, and current flow rate.
  • FIG. 12 is a graph displaying flow and pressure parameters 1300.
  • graph 1300 may provide various real-time data points for a blood vessel of interest in graphical or text format, include a current/desired setpoint flow 1302 as well as a maximum allowable reverse flow rate 1304 and a minimum allowable pressure at the proximal catheter 1306 for the blood vessel of interest.
  • Reverse flow rate and pressure proximal to a catheter are traced in real time 1314, for example showing data for the previous 60 seconds.
  • Other information that may be displayed includes target vessel for the location of the distal reverse flow catheter 1308, minimum and maximum allowable reverse flow rates/pressures 1304/1306, pressure on the proximal side of the valve/peristaltic pump 1310 (e.g. the pressure that a separate vacuum pump is providing or the venous pressure if the proximal line is connected to the patient’s venous system), and total fluid transferred 1312 (total fluid removed from the neurovasculature).
  • FIG. 13A is a graph displaying flow and pressure parameters in a vessel collapse scenario 1325.
  • graph 1325 begins with reverse flow 1326 operating nominally with an initial ramp up 1332 and then settling on the flow rate setpoint 1329.
  • the proximal catheter pressure Pl 1327 shows an initial drop and then holds steady at a pressure above the vessel-collapse pressure 1333.
  • Time is shown on the horizontal axis 1328. Due to some external change (e.g., within the patient’s neurovasculature), vessel collapse is imminent as indicated by a sudden drop in pressure 1335.
  • the system indicates an error and automatically lowers the reverse flow 1334, down to zero if necessary, to allow pressure to build back above the vessel-collapse pressure.
  • FIG. 13B is a graph displaying flow and pressure parameters in an aspiration/vacuum source disconnected scenario 1350.
  • graph 1350 begins with a flow reversal 1356 operating nominally 1360, reversing flow with the proximal catheter pressure Pl 1357 holding steady 1352 and flow holding steady 1360 at the current setpoint 1359 over time 1358.
  • a user disconnects the aspiration/vacuum source, opening the flow line to atmospheric pressure.
  • Pl proximal catheter pressure 1357 increases quickly 1353 and flow decreases quickly.
  • the system detects lower flow and opens the valve (e.g.
  • FIG. 13C is a graph displaying flow and pressure parameters for a flow reversal system response to avoid vessel collapse during a scenario in which a blood vessel lacks sufficient collaterals 1375.
  • an exemplary vessel may be partially or totally occluded with an embolus and a distal catheter is wedged with no collateral blood vessel branches between the distal catheter and the embolus to provide a source of blood.
  • a user may select a setpoint 1379 and start the system. The system slowly opens the valve, drawing fluid through it until flow and pressure drop as a result of not having an ongoing blood source.
  • the graphs 1382 and 1381 show proximal catheter pressure Pl 1377 and flow 1376 (respectively). Shown with time 1378 as the x axis. As Pl approaches 0, the flow reversal system recognizes this signature as indicating imminent vessel collapse and closes the valve.
  • the system automatically selects a lower flow rate as a percentage of previous flow rate setting 1379 and flow ramp rate (FRR) and makes another attempt to reach a desired, now lower, flow rate and begins to reopen the valve.
  • FRR flow ramp rate
  • the imminent collapse signature presents again 1382/1381 and again 1382/1381.
  • the system will settle on a zero or close-to-zero flow rate 1380.
  • “signature of collapse” may be low pressure with some flow while “signature of occlusion” may be low pressure with no flow, there may be no way for the system to determine if a lack of flow in a blood vessel of interest is due to occlusion or absence of collaterals, either way the system should prevent vessel collapse. If the system is unable to achieve a minimum reverse flow rate, the system may close the valve without an attempt to reopen it and indicate an error.
  • FIG. 14 is a flow rate table for various vessel locations 1400.
  • various vessel locations 1405 may include cerebral and upper body vasculature such as segments of the middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), carotid arteries, basilar artery, and other blood vessels that are common sites for embolic showering formation and have different characteristics including diameter, shape, length, and strength.
  • Flow rate table 1400 also provides examples of the maximum flow rates 1410 which should be applied for the various vessel locations 1405 to assist in preventing vessel collapse during aspiration.
  • the max flow rates shown in FIG. 14 are examples of the expected max flow rates for these vessels. For certain blood vessels having many collateral vessels, maximum flow may be higher to override the collateral vessels.
  • the table also provides flow rate ranges 1412 from which a maximum flow rate can be selected.
  • the maximum flow rate can also be adjusted based on feedback from the physician or user. For example, if the physician or user observes plentiful collateral flow under fluoroscopy with the injection of contrast, the physician may choose to set the maximum flow rate near the high end of the specified range.
  • flow rate table 1400 may also provide minimum flow rates or other data points.
  • information from flow rate table 1400 may be programmed into durable assembly of the flow reversal system for displaying and setting values such as flow rates and minimum and maximum allowable flow rates for a blood vessel of interest.
  • FIG. 15 is a flow chart depicting one example of a method of reversing flow in an occluded blood vessel 1500 using an apparatus as described herein.
  • a reverseflow catheter may first be placed proximally to an embolus within the vessel 1505 to sense proximal catheter pressure. This may be done in any appropriate manner, including guided by an imaging (e.g., fluoroscopy, ultrasound, etc.). The system may then determine and/or receive a vessel flow rate value specific to the vessel 1510, as described herein.
  • an imaging e.g., fluoroscopy, ultrasound, etc.
  • the user may enter one or more characteristics (including by selecting from a menu or library of options) that identifies the vessel (or that provides characteristics allowing identification of the vessel e.g., location, size, etc.) and the sizes of the catheters being used.
  • the apparatus may include a database indicating a range of vessel flow rates specific to the identified characteristic and/or identity of the vessel. See, e.g., FIG. 14, discussed above. This value may be adjusted based on, e.g., the location of the catheter within the vessel, the size and/or location of the clot material, etc.
  • reverse flow may be applied and maintained in the occluded blood vessel 1515 and controlled based on the changes to the pressure sensed via adjusting a valve coupled to the catheter, in which the valve is configured to produce a desired reverse flow rate setpoint in the occluded blood vessel while avoiding collapse of the blood vessel, in which the setpoint is reached via determining and implement a flow ramp rate.
  • reverse flow may be controlled by modulating the position of the valve coupled to the medical device based on pressure drop AP across the valve, flow, valve position, and a valve’s flow coefficient curve while ensuring that any suction or vacuum pressure within the catheter does not collapse the vessel.
  • the flow rate setpoint and flow ramp rate may be adjusted via the valve in response to feedback signaling vessel collapse or insufficient flow in the blood vessel, in which the feedback is based on changes to the sensed pressure, flow, and valve position 1520.
  • reverse flow may be optionally used in combination with the application high- flow aspiration 1625 from FIG. 16A to remove the embolus, as described.
  • the apparatus may be configured to switch the low-flow aspiration to a high-flow aspiration; the same separate vacuum pump may be used for both, or a separate vacuum pump may be used.
  • FIGS. 16A-16B is a flow chart depicting an example of a method for reversing flow 1600-1601.
  • the apparatus controls flow and pressure by controlling a pump (e.g., peristaltic pump). This may be performed instead of, or in some cases in addition to, controlling a flow-control valve as described in FIG. 15 and FIGS. 16A-16B.
  • a pump e.g., peristaltic pump
  • a distal end of a reverseflow aspiration catheter may be positioned within the vessel proximal to the embolus 1605, and the pressure within the catheter may be sensed by the one or more pressure sensors 1610.
  • the system may then determine and/or receive a vessel optimum reverse flow rate value (setpoint) within a vessel flow reversal system, with the flow rate value corresponding to or being specific to the vessel 1615 and/or sizes of the catheters being used, as described herein.
  • the system may also determine a flow ramp rate for reaching the optimum reverse flow rate value for the vessel 1620.
  • the apparatus may control reverse flow in the catheter by applying aspiration from the proximal end of the reverse-flow aspiration catheter that is coupled to a vessel flow reversal system, in which aspiration is based on controlling a value of the system to reach the optimum reverse flow rate based on the flow ramp rate 1625.
  • Method 1600-1601 continues at FIG. 16B.
  • the system prevents collapse of the vessel and insufficient flow in the vessel by adjusting the flow rate value and flow ramp rate via the valve, in which the adjusting is in response to feedback signaling changes to the sensed pressure and position of the valve, in which the adjusted flow rate value does not exceed the optimum reverse flow rate 1630.
  • the applied aspiration brings the embolus in contact with or near the distal end of the flow-reversal catheter 1635.
  • suction is applied in which the suction has a greater magnitude than a magnitude of the vessel optimum reverse flow rate value, and the magnitude of the suction is increased up to a maximum allowable value 1640.
  • reverse flow may be achieved via a peristaltic pump instead of a vacuum pump, or the combination of peristaltic and vacuum pumps.
  • the second catheter may be an aspiration catheter extending through the low flow/reverse flow catheter to ingest or cork the embolus.
  • the apparatus may be configured to switch the low-flow aspiration to a high-flow aspiration; the same pump may be used for both, or a separate pump may be used.
  • sterile covers may be used for the durable portion of the apparatus and/or sterilizing the disposable portion.
  • receiving includes receiving an indication of the vessel within which the distal end of the reverse-flow aspiration catheter is positioned.
  • preventing collapse of the vessel includes automatically shutting off or reduction aspiration/pump speed when the flow rate exceeds the vessel optimum reverse flow rate value.
  • the embolus is brought in contact with or near the distal end of the flow-reversal catheter via the applied aspiration, and suction is applied from a second catheter to capture all or a portion of the embolus into the flow-reversal catheter, in which the suction has a magnitude greater than a magnitude of the vessel optimum flow rate value, in which the magnitude of the suction is increased up to a maximum allowable flow.
  • the second catheter is coaxial with the reverse-flow aspiration catheter.
  • the second catheter is located in a different region of the patient’s neurovasculature.
  • preventing collapse of the vessel includes regulating a valve of the vessel flow reversal system that is connected between a source of negative pressure and the proximal end of the reverse-flow aspiration catheter.
  • controlling the flow rate of the applied aspiration includes sensing pressure from the source of negative pressure proximal to the valve, sensing the pressure distal to the valve, and adjusting the valve based on the vessel optimum reverse flow rate value.
  • positioning includes positioning within one of: an Ml segment of middle cerebral artery, an M2 segment of middle cerebral artery, an internal carotid artery, an external carotid artery, a common carotid artery, an Al segment of anterior cerebral artery, a basilar artery, and/or a Pl segment of posterior cerebral artery.
  • FIGS. 16C-16D show one example of a flow chart depicting one method for remote thrombectomy 1650-1651.
  • the apparatus controls the negative pressure by controlling a valve connected to a source of negative pressure (vacuum), such as a pressure pump (e.g., suction pump).
  • a source of negative pressure such as a pressure pump (e.g., suction pump).
  • the methods and apparatuses described herein may alternatively or additionally control the source of negative pressure (vacuum), such as a suction pump or peristaltic pump, directly; this may be performed instead of, or in some cases in addition to, controlling a flow-control valve.
  • a distal end of a reverse-flow aspiration catheter may be positioned within the vessel proximal to the embolus 1655, and the pressure within the catheter may be sensed by the one or more pressure sensors 1660.
  • the reverse-flow system may then regulate the aspiration at a relatively low flow in order to prevent collapse of the vessel, while still achieving reverse flow, and while remotely moving and capturing clot material.
  • the system and method may use feedback to maintain the aspiration (and any resulting flow) within a range that will prevent collapse, and/or adjusting the applied aspiration if collapse occurs or is likely to occur.
  • the system may determine and/or receive a vessel optimum reverse flow rate value (setpoint) within a vessel flow reversal system, with the flow rate value corresponding to or being specific to the vessel 1665, as described herein.
  • the system may also determine a flow ramp rate for reaching the optimum reverse flow rate value for the vessel 1670.
  • the apparatus may control reverse flow in the catheter by applying aspiration from the proximal end of the reverse-flow aspiration catheter that is coupled to an vessel flow reversal system, in which aspiration is based on controlling a value of the system to reach the optimum reverse flow rate based on the flow ramp rate 1675. This process may maintain the reverse flow which may, and may cause clot material to be dislodged and to move towards the reverse flow catheter, by application of the controlled aspiration from the reverse-flow catheter.
  • the exemplary methods may continue as shown in FIG. 16D.
  • the embolus is mobilized towards the aspiration catheter via the reversed flow 1680.
  • the reverse flow rate in the vessel may be increased past the optimum reverse flow rate value via further opening the valve to achieve or approach full aspiration, in which the increased reverse flow rate is below a maximum flow rate value for the vessel 1685.
  • the clot material at or approaching the distal end of the reverse flow catheter may be sensed or detected.
  • the clot material may clog, or partially or totally occlude the reverse flow catheter, which may be detected by a sensor and/or by pressure monitoring.
  • the embolus may then be aspirated through the aspiration catheter pursuant to approaching (or achieving) full aspiration 1690.
  • the flow reversal may be maintained, though the high flow rate (for full aspiration) may be reduced once the clot material has been removed.
  • the system may prevent collapse of the vessel and/or insufficient flow in the vessel by adjusting the flow rate value and flow ramp rate via the valve, in which the adjusting is in response to feedback signaling changes in the sensed pressure and position of the valve, in which the adjusted flow rate value does not exceed the optimum reverse flow rate value. This process may be repeated multiple times to remove additional clot material, in some examples, contrast may be applied to visualize clot material.
  • One or more components of the catheters described herein may include or be made from a variety of materials including one or more of a metal, metal alloy, polymer, a metal- polymer composite, ceramics, hydrophilic polymers, polyacrylamide, polyethers, polyamides, polyethylenes, polyurethanes, copolymers thereof, polyvinyl chloride (PVC), PEO, PEO- impregnated polyurethanes such as Hydrothane, Tecophilic polyurethane, Tecothane, PEO soft segmented polyurethane blended with Tecoflex, thermoplastic starch, PVP, and combinations thereof, and the like, or other suitable materials.
  • PVC polyvinyl chloride
  • PEO PEO- impregnated polyurethanes
  • Hydrothane Tecophilic polyurethane
  • Tecothane Tecothane
  • PEO soft segmented polyurethane blended with Tecoflex thermoplastic starch, PVP, and combinations thereof, and the like, or other suitable materials.
  • suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel -titanium alloy such as linear-elastic and/or super-elastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nickel-molybdenum alloy
  • Inner liner materials of the catheters described herein can include low friction polymers such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene), PTFE with polyurethane layer (Tecoflex). Reinforcement layer materials of the catheters described herein can be incorporated to provide mechanical integrity for applying torque and/or to prevent flattening or kinking such as metals including stainless steel, Nitinol, Nitinol braid, helical ribbon, helical wire, cut stainless steel, or the like, or stiff polymers such as PEEK.
  • low friction polymers such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene), PTFE with polyurethane layer (Tecoflex).
  • Reinforcement layer materials of the catheters described herein can be incorporated to provide mechanical integrity for applying torque and/or to prevent flattening or kinking such as metals including stainless steel, Nitinol, Nitinol braid,
  • Reinforcement fiber materials of the catheters described herein can include various high tenacity polymers like Kevlar, polyester, meta-para-aramide, PEEK, single fiber, multi-fiber bundles, high tensile strength polymers, metals, or alloys, and the like.
  • Outer jacket materials of the catheters described herein can provide mechanical integrity and can be contracted of a variety of materials such as polyethylene, polyurethane, PEBAX, nylon, Tecothane, and the like.
  • Other coating materials of the catheters described herein include paralene, Teflon, silicone, polyimide- polytetrafluoroetheylene, and the like.
  • Disposable assembly materials of the system described herein can include both elastomeric and rigid materials.
  • Elastomeric flow and pressure port lines may consist of chemically crosslinked polymers like silicone or polyurethane rubber.
  • thermoplastic elastomers/urethanes TPE/TPU
  • Rigid portions of the system may be made of harder thermoplastic polymers such as polycarbonate (e.g., Lexan), polyamide (e.g., Nylon), or polymethyl methacrylate (e.g., Acrylic).
  • the rigid portions of the disposable assembly may be affixed to the elastomeric portions via mechanical connection such as a barb fitting or chemical connection such as a chemical weld or UV adhesive (e.g.
  • Loctite 3104) or instant adhesive e.g. Loctite 4061
  • the inner or outer surfaces of the disposable assembly of the system described herein may be coated with materials such as paralene, silicone oil, polyimide, polytetrafluoroetheylene, fluorinated ethylene propylene, and the like.
  • Gas permeable/liquid impermeable materials of the system described herein e.g. transducer protector
  • FIGS. 17A and 17B illustrate examples of catheters that may be used with or as part of any of the apparatuses described herein, e.g., as a reverse-flow catheter.
  • any appropriate catheter may be used.
  • all wire and catheter manipulations can occur at or in close proximity to a single rotating hemostatic valve (RHV) or a multi-head RHV or through one or more RHVs co-located on the same device.
  • RHV rotating hemostatic valve
  • the guide sheath 17400 can be used to deliver smaller caliber flow reversal catheters, typically aspiration thrombectomy catheters, or the guide sheath can act as the flow reversal catheter when used with other devices such as stent retrievers, other stents, wires, balloons, or other retrievable devices.
  • the guide sheath 17400 can be any of a variety of commercially available guide sheaths.
  • the guide sheath 17400 can have an ID between 0.087”-0.091” such as the Walrus Balloon Guide catheter (Q’ Apel Medical Inc, Fremont CA), Terumo DESTINATION 6F (Terumo Europe NV), Cordis VISTA BRITE TIP (Cordis Corp., Hialeah, FL), and Penumbra NEURON MAX 088 (Penumbra, Inc., Alameda, CA), Stryker Infinity (Stryker Neurovascular, Fremont, CA) or comparable commercially available guiding sheath.
  • sheath sizes are described herein using the French (F) scale.
  • a sheath is described as being 6 French
  • the inner diameter of that sheath is able to receive a catheter having a 6F outer diameter, which is about 1.98 mm or 0.078”.
  • a catheter may be described herein as having a particular size in French to refer to the compatibility of its inner diameter to receive an outer diameter of another catheter.
  • a catheter may also be described herein as having a particular size in French to refer to its outer diameter being compatible with another catheter having a particular inner diameter.
  • the guide sheath 17400 may be a balloon guide catheter to enable flow arrest and flow reversal following balloon 17419 inflation.
  • the guide sheath 17400 can be a variety of sizes to accept various working devices, and can be accommodated to the operator’s preference.
  • the working lumen of the guide sheath 17400 can be sized to receive its respective catheter in a sliding fit. Generally, it is desirable to minimize the overall size of the vessel insertion site by limiting the outer diameter of the guide sheath 17400 to under 0.122”. It is also desirable to select corresponding outer and inner diameters to provide a good sliding fit between any telescoping catheter and the guide sheath 17400.
  • the working lumen of the guide sheath may have an inner diameter that is at least 0.001” larger than a maximum outer diameter of any catheter 17200 it is intended to receive.
  • the working lumen can have an inner diameter sized to accommodate at least 6 French catheters (1.98 mm or 0.078”), or at least 6.3 French catheters (2.079 mm or 0.082” OD), or at least 7 French (2.31 mm or 0.091” OD) catheters or 8 French (2.64 mm or 0.104” OD) or larger catheters.
  • the inner diameter of the guide sheath 17400 may be smaller or larger to be compatible with other catheter sizes.
  • the aspiration catheters (either or both the reverse-flow catheter and/or the high-flow aspiration catheter) described herein can have an ID of between 0.054” to 0.091”. If the catheter 17200 has a 0.088” inner diameter and have a maximum outer diameter of between 0.105” and 0.107”.
  • the guide sheath 17400 can, in turn, have a working lumen with an inner diameter that is between 0.106” and 0.108”. Generally, the difference or clearance between the maximum outer diameter of the catheter 17200 and the inner diameter of the guide sheath 17400 is less than about 0.002”, for example between 0.001” up to 0.002”.
  • the region of low clearance between the maximum outer diameter of the catheter 17200 and the inner diameter of the guide sheath 17400 can be limited to a localized region. Meaning, the low clearance fit between the two can extend only a fraction of a cylindrical length of the catheter 17200 and the sheath 17400.
  • the OD- ID difference between the catheter 17200 and the guide sheath 17400 can be greater than or equal to 0.002” along a first cylindrical length of where the two devices overlap during use and below 0.002” along a different cylindrical length of the overlap, thereby providing a localized region of low clearance within the overlap.
  • a distal region of the guide sheath 17400 can have a first inner diameter at a distal end region and a second, different inner diameter at a proximal end region such that the low clearance of the sliding fit with the catheter 17200 varies along its length.
  • the catheter 17200 has a first outer diameter at a distal end region and a second, larger outer diameter at a proximal end region.
  • the second, larger outer diameter can be less than 0.002” the inner diameter of the sheath 17400 and the first outer diameter greater than 0.002” the inner diameter of the sheath 17400. The provides a tighter overall fit between the guide sheath 17400 and the proximal end region of the catheter 17200 at the location of this second, larger outer diameter.
  • the sheath body 17402 can extend from a proximal furcation or rotating hemostatic valve (RHV) at a proximal end region 17403 to a tip 17406 at a distal end of the body 17402.
  • the proximal RHV may include one or more lumens molded into a connector body to connect to the working lumen of the body 17402 of the guide sheath 17400.
  • the working lumen can receive the catheter 17200 and/or any of a variety of working devices for delivery to a target anatomy.
  • the RHV can be constructed of thick-walled polymer tubing or reinforced polymer tubing.
  • the RHV allows for the introduction of devices through the guide sheath 17400 into the vasculature, while preventing or minimizing blood loss and preventing air introduction into the guide sheath 17400.
  • the RHV can be integral to the guide sheath 17400 or the guide sheath 17400 can terminate on a proximal end in a female Luer adaptor to which a separate hemostasis valve component, such as a passive seal valve, a Tuohy -Borst valve or RHV may be attached.
  • the RHV can have an adjustable opening that is open large enough to allow removal of devices that have adherent clot on the tip without causing the clot to dislodge at the RHV during removal.
  • the RHV can be removable such as when a device is being removed from the sheath 17400 to prevent clot dislodgement at the RHV.
  • the RHV can be a dual RHV or a multi-head RHV.
  • the RHV can form a Y-connector on the proximal end 17403 of the sheath 17400 such that the first port of the RHV can be used for insertion of a working catheter into the working lumen of the sheath 17400 and a second port into arm 17412 can be used for another purpose.
  • a flow line or a syringe or other device can be connected at arm 17412 via a connector 17432, in some examples to deliver a flush line for contrast or saline injections through the body 17402 toward the tip 17406 and into the target anatomy, or alternatively to remove blood or embolic material from the body.
  • the length of the catheter body 17402 is configured to allow the distal tip 17406 of the body 17402 to be positioned as far distal in the internal carotid artery (ICA), for example, from a transfemoral approach, with additional length providing for adjustments if needed.
  • ICA internal carotid artery
  • the length of the body 17402 can be in the range of 80 to 90 cm or can be longer, for example, up to about 100 cm or up to about 105 cm.
  • the body 17402 is configured to assume and navigate the bends of the vasculature without kinking, collapsing, or causing vascular trauma, even, for example, when subjected to high aspiration forces.
  • the guide sheath 17400 may include a tip 17406 that tapers from a section of the body 17402 leading up to the distal end. That is, the outer surface of the body 17402 may have a diameter that reduces from a larger dimension to a smaller dimension at a distal end.
  • the tip 17406 can taper from an outer diameter of approximately 0.114” to about 0.035” or from about 0.110” to about 0.035” or from about 0.106” to about 0.035”.
  • the angle of the taper of the tip 17406 can vary depending on the length of the tapered tip 17 406. For example, in some implementations, the tip 17406 tapers from 0.110” to 0.035” over a length of approximately 50 mm.
  • the guide sheath 17400 can have performance characteristics similar to other sheaths used in carotid access and AIS procedures in terms of kinkability, radiopacity, column strength, and flexibility.
  • the inner liners can be constructed from a low friction polymer such as PTFE (polytetrafluoroethylene) or FEP (fluorinated ethylene propylene) to provide a smooth surface for the advancement of devices through the inner lumen.
  • An outer jacket material can provide mechanical integrity to the inner liners and can be constructed from materials such as PEBAX, thermoplastic polyurethane, polyethylene, nylon, or the like.
  • the body 17402 can include a hydrophilic coating.
  • a third layer can be incorporated that can provide reinforcement between the inner liner and the outer jacket.
  • the reinforcement layer can prevent flattening or kinking of the inner lumen of the body 17402 to allow unimpeded device navigation through bends in the vasculature as well as aspiration or reverse flow.
  • the body 17402 can be circumferentially reinforced.
  • the reinforcement layer can be made from metal such as stainless steel, Nitinol, Nitinol braid, helical ribbon, helical wire, cut stainless steel, or the like, or stiff polymer such as PEEK.
  • the reinforcement layer can be a structure such as a coil or braid, or tubing that has been laser-cut or machine-cut to be flexible.
  • the reinforcement layer can be a cut hypotube such as a Nitinol hypotube or cut rigid polymer, or the like.
  • the outer jacket of the body 17402 can be formed of increasingly softer materials towards the distal end.
  • the flexibility of the body 17402 can vary over its length, with increasing flexibility towards the distal portion of the body 17402.
  • the guide sheath 17400 (as well as any of the variety of components used in combination with the sheath 17400) can be an over-the-wire (OTW) or rapid exchange type device, which will be described in more detail below.
  • the sheath 17400 can include a body 17402 formed of generally three layers, including a lubricious inner liner, a reinforcement layer, and an outer jacket layer.
  • the reinforcement layer can include a braid to provide good torqueability optionally overlaid by a coil to provide good kink resistance.
  • the polymers of the outer jacket layer can be generally higher durometer and thicker to avoid issues with kinking.
  • the wall thickness of such sheaths that are braided alone with thicker polymer can be about 0.011”.
  • the wall thickness of the sheaths 17400 described herein having a braid with a coil overlay provide both torqueability and kink resistance and can have a generally thinner wall, for example, a wall thickness of about 0.0085”.
  • the proximal end outer diameter can thereby be reduced to less than 0.112”, for example, about 0.107” outer diameter. It is generally beneficial to limit the overall OD of the guide sheath 17400 such that the entry wound into the patient (e.g. at the femoral artery) can be kept to a minimum size.
  • the sheath 17400 is a high-performance sheath 17400 that has good torque and kink resistance with a thinner wall providing an overall lower profile to the sub-system.
  • the thinner wall and lower profile allows for a smaller insertion hole through the vessel without affecting overall lumen size.
  • the wall thickness of the guide sheath 17400 can slowly step down to be thinner towards a distal end of the sheath compared to a proximal end.
  • the sheath body 17402 it is desirable for the sheath body 17402 to also be able to occlude the artery in which it is positioned, for example, during procedures that may create distal emboli. Occluding the artery stops antegrade blood flow and thereby reduces the risk of distal emboli that may lead to neurologic symptoms such as TIA or stroke.
  • the arterial access device or sheath 17400 can incorporate a distal occlusion balloon that upon inflation occludes the artery at the position of the sheath distal tip 17406.
  • the occlusion balloon can be inflated to occlude the vessel to reduce the risk of distal emboli to cerebral vessels.
  • the sheath 17400 can include an inflation lumen configured to deliver a fluid for inflation of the occlusion balloon in addition to the working lumen of the sheath 17400.
  • the inflation lumen can fluidly connect the balloon, for example, to arm 17412 on the proximal adaptor. This arm 17412 can be attached to an inflation device such as a syringe to inflate the balloon with a fluid when vascular occlusion is desired.
  • the arm 17412 may be connected to a passive or active vacuum or pump source to further reduce the risk of distal emboli.
  • the length of the guide sheath 17400 is long enough to access the target anatomy and exit the arterial access site with extra length outside of a patient’s body for adjustments.
  • the guide sheath 17400 (whether having a distal occlusion balloon or not) can be long enough to access the petrous ICA from the femoral artery such that an extra length is still available for adjustment.
  • any of these methods and apparatuses may include an additional catheter to provide high-flow aspiration, e.g., to remove clot material.
  • This second catheter may be referred to as an interventional catheter.
  • the same type of catheter used for reverse-flow may be used, or a larger-diameter catheter may be used including a balloon guide catheter.
  • One or more catheters 17200 may be configured to extend through and out the distal end of the guide sheath or balloon guide catheter 17400.
  • the catheter 17200 can be a distal access, support, or aspiration catheter depending on the method being performed.
  • FIGS. 18A-18B illustrate an example of a luer connector in an unlocked and locked position.
  • the use of these luer lock connections is for connection of the tubing, catheters, syringes, pumps, valves, and other elements of the system, but can result in clots getting stuck at a narrowing caused by these luer lock type connections.
  • the typical luer lock includes a first part 1802, typically on the end of a tubing or syringe which tapers to an end 1804 and fits inside the lumen of the second part 1806.
  • the end 1804 of the first part 1802 forms a point of narrowing of the connector lumen, potentially causing clots to get hung up and arrest flow through the tubing.
  • a clot or embolus being pulled through a catheter and associated tubing may become stuck at this point of relative narrowing. If the physician does not see free flow through the tubing or syringe they may not realize that the clot has been removed from the body and may therefore continue suction on a catheter which has its tip in the neurovasculature for longer than is needed. Alternatively, if only part of the clot has been aspirated and caught at the connector there will no longer be aspiration applied at the tip of aspiration catheter to recover the remaining clot(s). Essentially, these "stenoses" along the aspiration system are just an impediment to removing clots or embolic material from the neurovasculature.
  • FIG. 19 illustrates a sealing connector which minimizes the lip/narrowing and can eliminate the problem with clots getting stuck in this way within the system.
  • the sealing connector includes a first part 1912 having an internal thread configured to mate with an external thread of a second part 1916.
  • the sealing connector includes an O-ring seal 1914 or other internal elastomeric sealing element that provides a seal without the need for the tapered male part used in typical connectors.
  • the O-ring 1914 provides a seal between the first and second parts without the lip or change in lumen diameter which could cause the clot to get hung up within the lumen.
  • the sealing connector of FIG. 19 can be used for connection of any one or more of the elements of the system including tubing, catheters, syringes, vacuum pumps, valves, RHVs, pressure sensors or other elements of the system with no lip or minimal lip within the connection lumen.
  • FIG. 20 A illustrates an example of a sealing connector 2001 that includes a gasket seal 2002 or other internal elastomeric sealing element that provides a seal without the need for the tapered male part used in typical connectors.
  • the internal threads of the rotating cap 2003 allow another connector with external threads 2000 (e.g., luer connector) to be mated resulting in the compression of the gasket to stop leaks and lock the sealing connector and the threaded connector in one rigid joint.
  • FIG. 20B illustrates a sealing connector 2021 that includes a gasket seal 2022 or other internal elastomeric sealing element that provides a seal without the need for the tapered male part used in typical connectors.
  • the internal thread of the rotating cap 2023 allows another connector with external threads 2020 (e.g., luer connector) to be mated resulting in the compression of the seal to stop leaks.
  • an internal O-ring seal 2024 and washers 2025 enable a shaft 2026 to rotate freely without applying rotational torque to the gasket maintaining seal and allowing for swivel action.
  • FIG. 21 illustrates a vessel flow reversal system that meters or pumps fluid with a positive displacement peristaltic action of rollers 2106 mounted to a rotating pump head 2107 acting on an elastomeric flow line 2111 while it is held in place by a rigid backing arch 2109.
  • the pump head 2107 is driven by a motor and powertrain 2102 (e.g. stepper or servo motor or the like driving gears or pulleys with belts or other means of power transfer).
  • a PCBA with controller 2103 is used to control the motor/powertrain and receive inputs from the user interface 2104.
  • the example PCBA also includes pressure sensors that are in fluid communication, through transducer protectors 2101, with pressure sensing sites both distal and proximal of the flow reversal pump head. This example also shows proximal of the pump head an inline flow sensor 2105 as part of the disposable assembly.
  • the example vessel flow reversal system may include a flow line having a proximal end and a distal end, wherein the proximal end is configured to couple to a venous access sheath inserted into a patient’s venous system (e.g. at a femoral vein, subclavian vein, etc.) or be open to atmosphere and a distal end configured to couple to a neurovascular catheter as discussed before.
  • Flow sensor 2105 may be anywhere in the flow line, proximal or distal of the pump head. It may be part of the disposable assembly or may be part of the durable assembly (e.g., clamp-on flow sensor).
  • the example vessel flow reversal system of FIG. 21 may also include a rigid backing arch 2109 that is part of a flow-line control assembly 2110 that may be held in place by clamping knobs 2108.
  • a rigid backing arch 2109 that is part of a flow-line control assembly 2110 that may be held in place by clamping knobs 2108.
  • the flow-line control assembly and flow line are shown in an exploded view.
  • FIGS. 22A, 22B, and 22C show example pump head and flow-line control assembly configurations of a vessel flow reversal system.
  • fluid flow is left to right with the pump head rotating counter clockwise 2201.
  • the pump head may be rotating clockwise and the pump head/flow line may be in any orientation to achieve the vessel flow reversal.
  • FIG. 22A shows an example of a 7-roller pump head 2205 with a rigid symmetrical backing arch 2203 holding the elastomeric flow line in position against the pump head. Fluid is drawn into the pump and the elastomeric flow line is gradually compressed at the “intake area” 2206. As the rollers advance, they fully pinch down the elastomeric flow line in the “transfer area” 2204 such that it is not possible for fluid to flow backward through the pump. Finally, as the rollers advance, they gradually release the fluid into the “outlet area” 2202. Gradually compressing the flow line in the inlet area and then gradually releasing it in the outlet area minimizes both pressure and flow ripple in the neurovasculature.
  • FIG. 22B shows an example of the same 7-roller head from 22A, but with an eccentric backing arch 2226.
  • the gradual inlet area is minimized and the rollers immediately advance into the transfer area 2227, which is now left of center, but the outlet area 2225 is twice as long for a more gradual release of fluid.
  • the inlet area is twice as long, and the transfer area is right of center, with the gradual outlet area being minimized.
  • FIG. 22C shows an example 9-roller head 2251 with a symmetrical backing arch 2250.
  • the addition of 2 rollers reduces the length of the inlet, transfer, and outlet areas, which has the combined effect of making the backing arch assembly smaller 2252.
  • the backing arch may wrap around the pump head to extend the lengths of the inlet, transfer, and outlet areas. In some examples, the backing arch may completely wrap around the pump head such that the elastomeric flow line enters and leaves the durable assembly on the same side. In some examples wrap angles may be less than 360 degrees around the pump head (e.g., 60°, 90°, 120°, 180°, 270°, etc.).
  • the length of flow line within the pump may have an inner diameter in the range of 2 - 6 mm.
  • roller diameters may be in the range of 10 to 30 mm.
  • the head diameter may be in the range of 60 to 120 mm with the head diameter defined as the diameter of a circle centered at the pump head axis of rotation and circumscribing the outer diameters of all rollers.
  • the rollers do not fully pinch down in the transfer area and fluid back flow is possible, but pressure and flow ripple are reduced.
  • the intake and outlet areas of the backing arch may not be a constant transition into or out of the transfer area but may have more of a “non-linear geometry”, defined as a shape that results in the most even transfer of pressure energy into the fluid to minimize pressure/flow ripple.
  • the pump head motion control algorithm may vary the rate of rotation as a roller is transitioning into or out of the transfer area to even the transfer of pressure energy into the fluid and minimize pressure/flow ripple.
  • a vessel flow reversal system may use a peristaltic type head with a different number of rollers to minimize flow/pressure ripple (e.g. any number from 3 to 15 may be used).
  • FIG. 23 A shows an example flow reversal system where the elastomeric flow line 2304 is loaded into the flow-line control assembly 2305 by being stretched, placed within alignment slots 2302 (distal slot not shown) and held in the stretched state via collars 2301 (distal collar not shown) before being positioned against the pump head and locked in place (e.g. via thumb knobs 2108 of FIG. 21).
  • this pre-tension in the flow line prevents it from sliding when being squeezed by the rollers as the pump head rotates.
  • FIG. 23B shows an example with an inline embolus filter located distal of a neurovascular flow reversal system described herein, valve or pump.
  • the inline filter with an input flow line 2325 and an output flow line 2326; a filter body 2329 coupled to the input flow line and a housing 2327 coupled to the output flow line; a cylindrical filter element 2328 is coupled to the filter body such that there is no path from the input flow line to the output flow line except through the filter element.
  • the filter element may be made of a mesh of specific pore size (e.g., 7pm, 15pm, 25pm, 40pm, 60pm, 250pm etc.).
  • the mesh may be of polymeric material (e.g., polyamide/Nylon, polyester, etc.).
  • FIG. 24 shows an example of a display 2400 for a vessel reverse flow system.
  • Flow ripple 2401 and pressure ripple 2409 are minimized via methods described herein.
  • a sudden drop in proximal catheter pressure was detected approximately 30 seconds ago 2407 with pressure readings dipping below the minimum allowable pressure line 2408.
  • the system immediately stopped flow 2403 to allow pressure to rebuild until it crossed back over the minimum allowable pressure line at 2405. At that point, flow was ramped back up 2404 toward the flow rate setpoint 2402.
  • the horizontal time axis, 2406 in the example shown in FIG. 24 is a “negative flowing” trace with the most recent data always at the right margin and historical data extending back in time to the left.
  • Another example may be a “positive flowing” trace with a left-to-right moving sweep where the most recent data overlay previous data at the current position of the sweep.
  • Ripple in this context is defined as the peak-to-peak flow or pressure value when the average is held steady. For example, in FIG. 24, the flow peak-to-peak at 2401 is approximately 0.5 ml/min and the pressure peak-to-peak at 2409 is approximately 20mmHg.
  • the neurovascular reverse flow system display is a touch screen with touch controls implemented in software as graphical user interface (GUI) elements (e.g., buttons, sliders, editable fields, etc.).
  • GUI graphical user interface
  • Implementations describe catheters and delivery systems and methods to deliver catheters to target anatomies.
  • a target vessel of a neurovascular anatomy such as a cerebral vessel
  • the implementations are not so limited and certain implementations may also be applicable to other uses.
  • the catheters can be adapted for delivery to different neuroanatomies, such as subclavian, vertebral, carotid vessels as well as to the coronary anatomy or peripheral vascular anatomy, to name only a few possible applications.
  • the systems described herein are described as being useful for treating a particular condition or pathology, that the condition or pathology being treated may vary and are not intended to be limiting.
  • embolus used interchangeably and can include, but are not limited to a blood clot, air bubble, small fatty deposit, or other object carried within the bloodstream to a distant site or formed at a location in a vessel.
  • the terms may be used interchangeably herein to refer to something that can cause a partial or full occlusion of blood flow through or within the vessel.
  • relative terms throughout the description may denote a relative position or direction.
  • distal may indicate a first direction away from a reference point.
  • proximal may indicate a location in the second direction opposite to the first direction.
  • such terms are provided to establish relative frames of reference, and are not intended to limit the use or orientation of the catheters and/or delivery systems to a specific configuration described in the various implementations.
  • the word “about” means a range of values including the specified value, which a person of ordinary skill in the art would consider reasonably similar to the specified value. In embodiments, about means within a standard deviation using measurements generally acceptable in the art. In embodiments, about means a range extending to +/— 10% of the specified value. In embodiments, about includes the specified value.
  • phrases such as “at least one of’ or “one or more of’ may occur followed by a conjunctive list of elements or features.
  • the term “and/or” may also occur in a list of two or more elements or features. Unless otherwise implicitly or explicitly contradicted by the context in which it is used, such a phrase is intended to mean any of the listed elements or features individually or any of the recited elements or features in combination with any of the other recited elements or features.
  • the phrases “at least one of A and B;” “one or more of A and B;” and “A and/or B” are each intended to mean “A alone, B alone, or A and B together.”
  • a similar interpretation is also intended for lists including three or more items.
  • phrases “at least one of A, B, and C;” “one or more of A, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together.”
  • the durable valve and pump systems and disposable flow line systems disclosed herein may be packaged separately, where the flow line disposable assembly is sterilized in a packaging system that protects it from damage that can occur during shipping and handling.
  • the finished package would be sterilized using sterilization methods such as Ethylene oxide or radiation and labeled and boxed.
  • sterilization methods such as Ethylene oxide or radiation
  • the durable assembly would be covered in sterile plastic film when presented to the sterile field so that any non-sterile surfaces are inaccessible. Instructions for use may also be provided in-box or through an internet link printed on the label.
  • any of the methods (including user interfaces) described herein may be implemented as software, hardware or firmware, and may be described as a non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a processor (e.g., computer, tablet, smartphone, etc.), that when executed by the processor causes the processor to control perform any of the steps, including but not limited to: displaying, communicating with the user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like.
  • any of the methods described herein may be performed, at least in part, by an apparatus including one or more processors having a memory storing a non-transitory computer-readable storage medium storing a set of instructions for the processes(s) of the method.
  • computing devices and systems described and/or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein.
  • these computing device(s) may each comprise at least one memory device and at least one physical processor.
  • memory or “memory device,” as used herein, generally represents any type or form of volatile or non-volatile storage device or medium capable of storing data and/or computer-readable instructions.
  • a memory device may store, load, and/or maintain one or more of the modules described herein.
  • Examples of memory devices comprise, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory.
  • processor or “physical processor,” as used herein, generally refers to any type or form of hardware-implemented processing unit capable of interpreting and/or executing computer-readable instructions.
  • a physical processor may access and/or modify one or more modules stored in the above-described memory device.
  • Examples of physical processors comprise, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor.
  • the method steps described and/or illustrated herein may represent portions of a single application.
  • one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as the method step.
  • computer-readable medium generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions.
  • Examples of computer-readable media comprise, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic- storage media (e.g., hard disk drives, tape drives, and floppy disks), optical -storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems.
  • transmission-type media such as carrier waves
  • non-transitory-type media such as magnetic- storage media (e.g., hard disk drives, tape drives, and floppy disks), optical -storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media),
  • the processor as described herein can be configured to perform one or more steps of any method disclosed herein. Alternatively or in combination, the processor can be configured to combine one or more steps of one or more methods as disclosed herein.
  • the device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
  • the terms “upwardly”, “downwardly”, “vertical”, “horizontal” and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.
  • first and second may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.
  • any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and/or steps may alternatively be exclusive and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps.
  • all numbers may be read as if prefaced by the word "about” or “approximately,” even if the term does not expressly appear.
  • a numeric value may have a value that is +/- 0.1% of the stated value (or range of values), +/- 1% of the stated value (or range of values), +/- 2% of the stated value (or range of values), +/- 5% of the stated value (or range of values), +/- 10% of the stated value (or range of values), etc.
  • Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then “about 10" is also disclosed.
  • any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that “less than or equal to” the value, “greater than or equal to the value” and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X” is disclosed the “less than or equal to X” as well as “greater than or equal to X” (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points.

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Abstract

L'invention concerne des dispositifs d'inversion de flux ainsi que des procédés et des appareils configurés pour commander le débit appliqué à partir d'un cathéter (par exemple, un cathéter d'aspiration à flux inversé) sur la base d'une ou de plusieurs entrées de capteur et du type et/ou de la taille du vaisseau, tout en empêchant l'effondrement du vaisseau. Ces procédés et appareils peuvent inverser et ajuster le flux pour aider à l'élimination du matériau embolique du système neurovasculaire.
PCT/US2024/052527 2023-10-23 2024-10-23 Systèmes et procédés de modulation de flux inverse pour éviter un effondrement de vaisseau pendant une embolectomie Pending WO2025090581A1 (fr)

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