WO2025042811A1 - Catheter blood pumps and associated methods - Google Patents

Abstract

Intravascular blood pumps systems and methods of use are provided. The blood pump system comprises an expandable shroud forming a blood conduit. The shroud comprises a distal section, a proximal impeller section, and a central section between the distal section and the proximal impeller section. The central section comprises a helical pattern in which at least one of a pitch angle or a strut thickness varies along a transitional portion of the central section.

Description

CATHETER BLOOD PUMPS AND ASSOCIATED METHODS

CLAIM OF PRIORITY

[0001] This application claims priority to U.S. Patent Application No. 63/520,582, filed August 18, 2023, titled “CATHETER BLOOD PUMPS AND ASSOCIATED METHODS,” and to U.S. Patent Application No. 63/589,492, filed October 11, 2023, titled “CATHETER BLOOD PUMPS AND ASSOCIATED METHODS,” which are both herein incorporated by reference in their entirety.

INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

BACKGROUND

[0003] Patients with heart disease can have severely compromised ability to drive blood flow through the heart and vasculature, presenting for example substantial risks during corrective procedures such as balloon angioplasty and stent delivery. Intra-aortic balloon pumps (IABP) are used to support circulatory function, such as treating heart failure patients. An IABP is typically placed within the aorta and inflated and deflated in counter-pulsation fashion with the heart contractions, with one function being to provide additive support to the circulatory system. Use of lABPs is common for treatment of heart failure patients, such as supporting a patient during high-risk percutaneous coronary intervention (HRPCI), stabilizing patient blood flow after cardiogenic shock, treating a patient associated with acute myocardial infarction (AMI) or treating decompensated heart failure. Such circulatory support may be used alone or in with pharmacological treatment.

[0004] Catheter blood pumps have been known for support of hemodynamically unstable patients for decades. Catheter blood pumps are inserted into the body in connection with the cardiovascular system to pump arterial blood from the left ventricle into the aorta to add to the native blood pumping ability of the left side of the patient’s heart. Another known method is to pump venous blood from the right ventricle to the pulmonary artery to add to the native blood pumping ability of the right side of the patient’s heart. An overall goal is to reduce the workload on the patient’s heart muscle to stabilize the patient, such as during a medical procedure that may put additional stress on the heart, to stabilize the patient prior to heart transplant, or for continuing support of the patient.

[0005] One such blood pump, the Hemopump, was developed in 1980’s as the first percutaneous blood pump. The Hemopump included a rotary pump guided by a catheter with a long, flexible inflow extension. The Hemopump had an axial flow design to improve flow efficiency for the given catheter profile. The Hemopump was expanded to several sizes. However, the smaller size of 14Fr required a surgical cutdown and provided inadequate flow. The 21Fr version had increased risk of complications and limited additional flow.

[0006] Efforts have been made to provide higher flow while limiting the introduction profile of the catheter. Examples include the expandable pump shown in US Pat. No. 5,749,855 to Reitan (“the ‘855 patent”). The ‘855 patent describes an expandable impeller within protective outer filaments. The impeller blades are hinged to allow the entire pump to be collapsed for introduction and expanded within the body. However, the hydraulic efficiency suffers because the impeller rotates within the large vessel and thus cannot generate pressure to create flow.

[0007] Other examples include US Pat. No. 7,393,181 to McBride (“the ‘ 181 patent”), US Pat. No. 9,446,179 to Keenan (“the ‘ 179 patent”), US Pat. No. 9,512,839 to Liebing (“the ‘839 patent”), and US Pat. No. 6,533,716 to Schmitz-Rode (“the ‘716 patent”). These references all describe expandable pumps formed with expandable impellers within expandable shrouds. However, these pumps involved complicated designs.

[0008] For example: the ‘716 patent provides a design with an unsupported flow lumen. With no support in the flow lumen, the blood pump lacks hydraulic efficiency and risks impeller rubbing on or contacting an inner diameter of the flow lumen. The ‘ 181 patent and similar pumps require a drive shaft to extend through the impeller and terminate at a bearing at a distal end of the shroud. The ‘ 179 patent and the ‘839 patent both describe a distal bearing within the shroud. Each of these require extra moving parts, which increases hemolysis and the risk of thromboembolic events. The additional structure(s) also add or lengthen sections of increased stiffness in the pump, making it harder to introduce the pump and causing the pump to be stiff across the aortic valve and within the ventricle. The ‘839 patent also involves placing the high-speed impeller in the ventricle which is believed to cause risk of complications.

[0009] There is a need for a true percutaneous pump that can provide adequate cardiac support for a variety of heart failure populations. There is a need for a pump that is easy to introduce and track, and that is adaptable to the anatomy. There is a need for a pump with reduced risk of injury and complications. SUMMARY OF THE DISCLOSURE

[0010] In general, there is provided a catheter blood pump comprising an expandable shroud forming a blood conduit. The shroud can have a distal section, a proximal impeller section, and a central section between the distal section and the proximal impeller section. The central section may comprise a plurality of helically winding scaffold elements, wherein at least one of a pitch angle and a strut thickness of the helically winding scaffold elements varies along a transitional portion of the central section. An impeller disposed at least partially within the proximal impeller section.

[0011] In some examples, the strut thickness of the helically winding scaffold elements may decrease from first thickness to second thickness along the transitional portion. The strut thickness of the helically winding scaffold elements may decrease from a proximal side of the transitional portion to a distal side of the transitional portion. The pitch angle of the helically winding scaffold elements may increase from a first angle to a second angle along the transitional portion. The pitch angle of the helically winding scaffold elements may increase from a proximal side of the transitional portion to a distal side of the transitional portion. The pitch angle of the helically winding scaffold elements may increase at a ratio of approximately 1 : 1.2. The pitch angle of the helically winding scaffold elements may increase 120% from a proximal side of the transitional portion to a distal side of the transitional portion. The pitch angle may increase 10° from a proximal side of the transitional portion to a distal side of the transitional portion.

[0012] In some examples, the transitional portion can be adjacent to the proximal impeller section. The transitional portion can be stiffer than a remainder of the central section. The transitional portion may further comprise a first transitional portion, the catheter blood pump may further comprise a second transitional portion distal to the constant pitch portion.

[0013] In one aspect, the catheter blood pump may further comprise a constant pitch portion distal to the transitional portion in which the pitch angle of the plurality of helically winding scaffold elements

[0014] In some examples, at least one of the pitch angle and the strut thickness of the helically winding scaffold elements may vary along the second transitional portion. The pitch angle of the helically winding scaffold elements may vary from a first pitch angle to a second pitch angle along the first transitional portion, and may vary from the second pitch to a third pitch angle along the second transitional portion. The first pitch angle can be substantially similar to the third pitch angle. The strut thickness of the helically winding scaffold elements may reduce along the first transitional portion and increases along the second transitional portion. [0015] In general, there is provided a catheter blood pump comprising an expandable shroud forming a blood conduit, the shroud can have a distal section, a proximal impeller section, and a central section between the distal section and the proximal impeller section. The central section may comprise a helical pattern with at least one variable pitch region positioned in the central section in which helical elements of the blood conduit transition from a first pitch angle to a second pitch angle.

[0016] In some examples, a flexibility of the variable pitch region may increase distally along the variable pitch region. A strut thickness of the helical elements may decrease from a proximal side of the variable pitch region to a distal side of the variable pitch region. The pitch angle of the helical elements may increase across the variable pitch region. The variable pitch region may be adjacent to the proximal impeller section. The variable pitch region may comprise a first variable pitch region, and wherein the catheter blood pump may further comprise a second variable pitch region.

[0017] In some examples, the helical elements can transition from the second pitch angle to a third pitch angle in the second variable pitch region. The first pitch angle may be substantially similar to the second pitch angle.

[0018] In general, there is provided a catheter blood pump, comprising a flexible catheter and a blood pump portion coupled to a distal end of the flexible catheter. The blood pump portion may comprise an expandable and collapsible scaffold forming an inlet portion, and outlet portion, and a flexible central portion disposed between the inlet portion and the outlet portion. The flexible central portion can comprise a plurality of helical elements having a pitch angle that varies along specified portions of the flexible central portion. A blood impermeable membrane may be disposed on the scaffold and forming a blood conduit between the inlet portion and the outlet portion. An impeller can be disposed within the conduit near or partially within the outlet portion. A flexible distal tip may be coupled to a distal end of the blood pump portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIGS. 1 A-1C are side elevation views of a blood pump with a blood conduit comprising an expandable scaffold.

[0020] FIGS. 2A-2E are detailed flattened views of the expandable scaffold of blood pumps, as described herein.

[0021] FIGS. 3 A-3D are side elevation views of exemplary blood pumps showing the expandable scaffold of the blood conduit and various examples of positioning markers. [0022] FIG. 4 is a detailed cross section view of a blood pump proximal section showing an impeller positioned in the blood conduit.

[0023] FIG. 5 shows a detailed perspective view of the proximal end of a blood conduit. [0024] FIG. 6 shows a cross section of distal tip of a blood pump.

[0025] FIGS. 7A-7B are side elevation views shown with a cross section of the blood conduit proximal section to reveal examples of deflection in response to forces applied against the blood pump including the tip gap between the impeller and the blood conduit.

[0026] FIGS. 8A-8B are various views of blood conduits and associated flattened scaffold configurations.

[0027] FIGS. 9A-9C are side elevation views of blood conduits with examples of bend radii. [0028] FIG. 10 is a perspective view of a blood pump positioned in a patient’s anatomy with a cross section of the anatomy to reveal the position and configuration of the blood pump therein.

DETAILED DESCRIPTION

[0029] Minimally-invasive rotary blood pumps are provided that can be inserted into the body in connection with the cardiovascular system to, e.g., pump arterial blood from the left ventricle into the aorta to add to the native blood pumping ability of the left side of the patient’s heart. An overall goal for the use of such blood pumps is to reduce the workload on the patient’s heart muscle to stabilize the patient, such as during a medical procedure that may put additional stress on the heart, to stabilize the patient prior to heart transplant, or for continuing support of the patient.

[0030] FIG. 1 A shows an example of an intravascular blood pump 100. The blood pump 100 includes an expandable/collapsible blood conduit 102 that is configured to transition between an expanded state, as shown in FIG. 1 A, and a collapsed state (not shown). For example, the conduit 102 may be in the collapsed state when confined within a delivery catheter for delivery to the heart, expanded upon release from the delivery catheter for blood pumping, and collapsed back down within the delivery catheter (or other catheter) for removal from heart. When in the expanded state, the conduit 102 is radially expanded so as to form an inner lumen for passing blood therethrough. When in the expanded state, the inner lumen of the conduit 102 may be configured to accommodate blood pumped by an impeller disposed therein.

[0031] In this example, the blood pump 100 includes a collapsible and expandable impeller 104 within a proximal portion of the conduit 102. The conduit 102 includes a first (e.g., proximal) end having an inlet 101, and a second (e.g., distal) end having an outlet 103. The inlet 101 may allow blood to exit the conduit 102 and the inlet 103 may allow blood to enter the conduit 102. The impeller 104 may be configured to pump blood from the inlet toward the outlet. In an exemplary operating position, the inlet 103 may be distal to the aortic valve, in the left ventricle, and the outlet may be proximal to the aortic valve (e.g., in the ascending aorta). Although only a single impeller is illustrated, it should be understood that in some embodiments, the blood pump can include a plurality of impellers.

[0032] The exemplary conduit 102 includes a tubular expandable/collapsible scaffold 106 that provides structural support for a membrane 108 that covers at least a portion of inner surfaces and/or outer surfaces of the scaffold 106. In some examples, the membrane extends from the inlet to the outlet but does not cover the inlet or outlet, to allow blood to enter and exit the blood conduit. In some examples, the membrane may cover a portion of the inlet and/or outlet, but not the entirety of either the inlet or outlet. The scaffold 106 defines a supported lumen or blood conduit with radial strength to maintain blood flow during operation of the blood pump. The exemplary conduit is formed to be fluid impermeable by the membrane. The membrane may be attached to the scaffold, cover the scaffold, be sandwiched or molded around the scaffold, or integrated into the scaffold, and other configurations as would be understood by one of skill from the description herein. The exemplary scaffold 106 includes a material having a pattern or plurality of openings with the membrane 108 covering the openings to retain the blood within the lumen of the conduit 102. The scaffold 106 may be unitary and may be made of a single piece of material. For example, the scaffold 106 may be formed by cutting (e.g., laser cutting) a tubular shaped material. Exemplary materials for the scaffold 106 may include one or more of nickel titanium (nitinol), cobalt alloys, and polymers, although other materials may be used.

[0033] The exemplary scaffold 106 includes proximal struts 112a extending at a proximal end near the outlet forming a plurality of openings (e.g., blood outlet region) and distal struts 112b that extend from the scaffold 106 near the inlet 103 forming a plurality of openings (e.g., blood inlet region). The proximal struts 112a are coupled to first hub 114a of a shaft 110 of a catheter. The distal struts 112b are coupled to second hub 114b. The second or distal hub 114b can be coupled, connected to, or integral with an atraumatic distal tip 116. The distal tip 116 can be extremely flexible and compliant. In some examples, the distal tip can include a distal bend or curvature, just as a J-tip, a pigtail tip, or the like. In this example, the first hub 114a includes a bearing assembly through which a central drive cable extends. The drive cable is operationally coupled to and configured to rotate the impeller 104.

[0034] The conduit 102 has a proximal region 118, a central region 120, and a distal region 122. The central region 120 may be configured to be placed across a valve (e.g., aortic valve) such that the proximal region 118 is configured to be placed at least partially within a first heart region (e.g., ascending aorta) and the distal region 122 is at least partially within a second heart region (e.g., left ventricle). The proximal region 118 may be configured to house an impeller therein. As shown, the blood conduit 102 can have a substantially constant diameter.

[0035] The distal tip 116, conduit 102, and shaft 110 can each include sections of increased flexibility (e.g., less stiffness) relative to other sections of the blood pump. The increased flexibility sections are configured to deflect or bend when a load is applied to the blood pump 100. In some implementations, distal shaft portion 111 of shaft 110, central region 120 of conduit 102, and distal tip section 113 of distal tip 116 are the most flexible regions or sections of the blood pump 100.

[0036] For example, still referring to FIG. 1 A, the shaft 110 can include a distal shaft portion 111 that is more flexible than other sections of the shaft 110. The distal shaft portion 111 can achieve increased flexibility by having a reduced braid density, reduced durometer, and/or reduced wall thickness compared to other sections of the shaft 110.

[0037] Additionally, the conduit 102/scaffold 106 can include a central region 120 that is more flexible than the proximal region 118 and distal region 122 of the conduit. The scaffold pattern/design has been optimized to give the central region 120 more flexibility and reduced stiffness relative to the rest of the scaffold. For example, the central region 120 can include a section of helically winding scaffold elements with an optimized pitch and decreased element width to facilitate flexibility and bending in response to the anatomy while resisting kinking or collapse of the conduit. In some embodiments, the central region 120 includes only the helically winding scaffold elements, without any axially or radially connecting elements between adjacent helical elements.

[0038] Furthermore, the distal tip 116 can include a distal tip section 113 that is also extremely flexible/compliant. The increased flexibility of the distal tip section 113 can be achieved with decreased durometer sections and/or decreased wall thickness. The length of the distal tip 116 is configured to allow the blood pump to “dock” or rest in the ventricle apex to reduce movement of the overall assembly during use. The flexible distal tip section 113 allows for bending and accommodation of heart contraction, pump movement and varying anatomy. Additionally, the distal tip section 113 can include varying wall thickness and durometer to optimize bending and to distribute loads to other sections of the blood pump 100 (e.g., to the central region 120 or the distal shaft portion 111.

[0039] In FIGS. 1 A-1C, the distal portion 122 of the scaffold can also include a distal section 125 of increased element density to increase stiffness around the inlet section. The distal section 125 of the distal portion 122 can include a plurality of axial elements 121b. The distal section 125 can include elements, such as axial elements 121b, with an increased width relative to other elements in the scaffold (e.g., the helical elements in central section 120) to provide increased stiffness in distal section 125. Additionally, the distal struts 112b can have a tapered leg design with a wider base near the distal section 125 that tapers to a narrower portion where they attach to hub 114b that is optimized for stiffness in the inlet region of the blood pump.

[0040] Similarly, in FIGS. 1 A-1C, the proximal portion 118 of the scaffold can also include a proximal section 119 of increased element density to increase stiffness around the outlet section. The proximal section 119 of the proximal portion 118 can include a plurality of axial elements 121a. The proximal section 119 can include elements, such as axial elements 121a, with an increased width relative to other elements in the scaffold (e.g., the helical elements in central section 120) to provide increased stiffness in proximal section 119. Additionally, the proximal struts 112a can have a tapered leg design with a wider base near the proximal section 119 that tapers to a narrower portion where they attach to hub 114a that is optimized for stiffness in the outlet region of the blood pump.

[0041] Also shown in FIGS. 1A-1C, the central portion 120 can include a plurality of helical elements 129 with a pitch and width optimized to facilitate bending in the central portion without kinking. The central portion 120 must be sufficiently flexible so that it is softer than the anatomical structures it will be positioned against. Allowing for bending without kinking allows for flow performance to be maintained in a variety of operating conditions. Therefore, accommodating the anatomy does not come at the cost of flow performance.

[0042] In some aspects, the scaffold 106 shown in FIGS. 1A-1C can generally be divided into five distinct sections, from left to right (proximal to distal) on the page: 1) outlet 101, 2) proximal section 119, 3) central region 120, 4) distal section 125, and 5) inlet 103. As described above, the scaffold can include central region 120 which can include flexible helical elements that are designed to bend without kinking or collapsing, allowing flow performance to be maintained in a variety of operating conditions.

[0043] Accommodating the anatomy does not come at the cost of flow performance. The central section must be sufficiently flexible so that it’s softer than anatomical structures and gives way when the blood pump contacts the anatomy. The scaffold further includes stiffer sections 119 (around the impeller 104) and 125 (towards the inlet section). Furthermore, the sections around the proximal and distal struts (the inflow and outflow sections) are also relatively stiff. In combination with sections 119 and 125, the sections on the proximal and distal ends of the scaffold function as a relatively stiff beam, especially compared to the flexible central portion. Thus, the central portion will always give or bend first when a side load is applied to the scaffold (e.g., contact with the anatomy).

[0044] FIG. IB is a close-up view of a blood conduit 102 of the blood pump 100, including scaffold 106, membrane 108, proximal struts 112a, outlet 101, distal struts 112b, and inlet 103. As previously described, the conduit 102 can include a proximal region 118, a central region 120, and a distal region 122. This includes design elements that allow specified sections or portions of the blood conduit to be flexible while other specified portions or sections of the blood conduit are stiff. In some embodiments, the helical elements 129 have a width that is less than a width of elements in section 119 of the proximal portion 118 and section 125 of the distal portion 122.

[0045] In FIG. IB, the proximal region 118 of the scaffold can include a proximal section 119 of increased element density to increase stiffness around the impeller and the outlet section. The proximal section 119 of increased element density can include a plurality of axial elements 121a connected to a plurality of radial elements 123a. In some embodiments, the radial elements can be arranged in a chevron pattern or arrangement of diagonal elements. In the illustrated embodiment, the axial elements 121a are positioned between two sections or rows of radial elements 123a and 123b. In some embodiments, the radial and axial elements within the proximal section 119 can have increased width relative to other elements in the scaffold (e.g., the helical elements in central section 120) to provide increased stiffness in proximal section 119. Additionally, the proximal struts 112a can have a tapered leg design with a wider base near the proximal section 119 that tapers to a narrower portion where they attach to hub 114a that is optimized for stiffness in the outlet region of the blood pump.

[0046] Additionally, the distal section 125 of increased element density can include a plurality of axial elements 121b connected to a plurality of radial elements 123c and 123d. In some embodiments, each set of radial elements can be arranged in a chevron pattern or arrangement of diagonal elements. In the illustrated embodiment, the axial elements 121b are positioned between a first section or row of radial elements 123 c and a second section or row of radial elements 123d. In some embodiments, the radial and axial elements within the distal section 125 can have increased width relative to other elements in the scaffold (e.g., the helical elements 129 in central section 120) to provide increased stiffness in section 125. Additionally, the distal struts 112b can have a tapered leg design with a wider base near the distal section 125 that tapers to a narrower portion where they attach to hub 114b that is optimized for stiffness in the inlet region of the blood pump.

[0047] In the embodiment of FIG. IB, the helical elements 129 of the central region 120 may have a relatively constant pitch throughout a majority of the central region 120. For example, the pitch or angle of the helical elements relative to other elements in the blood conduit (such as axial elements 121 a/12 lb) can be the same or substantially the same along the length of the central region 120.

[0048] The overall length of the blood conduit 102 in FIG. IB can be approximately 60- 80mm. In some examples, the length of the proximal section 118 is determined by the length of the impeller. While flexibility is desirable in the central section 120, structural rigidity can be advantageous in the distal section 122 to maintain the structure of the inlet and also allow for pushability of the blood pump/conduit, such as during pump positioning. Therefore, in one embodiment, adjustments in the overall length of the blood conduit can be implemented by increasing a length of the axial elements 121b between the rows of radial elements 123c and 123d. For example, a 60mm long pump conduit may include identically dimensioned proximal and central sections to a 70mm or 80mm long pump conduit. However, the longer pump conduits may have increased length in the distal section 122 relative to the shorter pump versions. This increased length may be implemented by increasing the length of axial elements 121b.

[0049] FIG. 1C shows another example of a blood conduit 102, which can be divided into distinct sections including the proximal region 118, central region 120, and distal region 122. As described above, the central portion 120 can include flexible helical elements 129 that are designed to bend without kinking or collapsing, allowing flow performance to be maintained in a variety of operating conditions. The blood conduit 102 in FIG. 1C is also shown to include membrane 108, proximal struts 112a, outlet 101, distal struts 112b, and inlet 103. [0050] The conduit example in FIG. 1C may comprise any of features described above, including proximal and distal struts 112a/l 12b , axial elements 121a/121b, and radial elements 123a-123c. It should be noted that while FIG. 1C has two rows of radial elements 123a-123b in the proximal section 119 similar to the embodiment of FIG. IB, the distal section 125 in FIG. 1C has only a single row of radial elements 123c.

[0051] The overall length of a blood conduit described in FIG. 1C can be approximately 60- 100mm. In some examples, the length of the proximal section 118 is determined by the length of the impeller. While flexibility is desirable in the central section 120, structural rigidity can be advantageous in the distal section 122 to maintain the structure of the inlet 103 and also allow for pushability of the blood pump/conduit, such as during pump positioning. Therefore, in one embodiment, adjustments in the overall length of the blood conduit can be implemented by increasing a length of the axial elements 121b between the struts 112b and of the row of radial elements 123c. [0052] Any of the blood pumps described herein may have a blood conduit 102 with one or more variable pitch regions. Referring to FIG. 1C, variable pitch regions 170 and 171 are shown in the central region 120. The variable pitch regions may comprise a region within the central region 120 in which the pitch or angle of the helical elements 129 changes or varies. For example, a variable pitch region may comprise a region in which helical elements of the central region transition or vary from a first angle or pitch to a second angle or pitch. In some examples, the variable pitch regions may further comprise a transition in attributes of the helical elements, such as transitions in the thickness, stiffness, angle, or arrangement across the length of the variable pitch region. The variable pitch regions may be interspersed within or adjacent to constant pitch regions 172 and 173 of the central region. In contrast to the variable pitch regions, the constant pitch regions may comprise a region in which helical elements of the central region maintain a constant pitch or angle.

[0053] In the specific example of FIG. 1C, variable pitch region 170 may comprise helical struts 129 that transition from a first pitch to a second pitch. In some examples, the first pitch may be approximately 50 degrees and the second pitch may be approximately 60 degrees (e.g., a ratio of approximately 1: 1.2). In the constant pitch region 172, the pitch of the helical elements may be maintained at the second pitch from the variable pitch region 170.

However, this pitch may transition again in variable pitch region 171. In some examples, the pitch of the helical elements may transition from the second pitch to a third pitch. In some examples, the third pitch may be substantially similar to the first pitch. For example, in one embodiment, the pitch of the helical elements may transition from approximately 50 degrees to approximately 60 degrees in variable pitch region 170, maintain 60 degrees in constant pitch region 172, and then transition from approximately 60 degrees to approximately 50 degrees in variable pitch region 171. Finally, constant pitch region 173 may maintain the same or constant pitch of the helical elements until they terminate or transition into axial elements 121b. For example, if the pitch of helical elements transition from approximately 60 degrees to approximately 50 degrees in variable pitch region 171, then the helical elements can maintain a relatively constant pitch of approximately 50 degrees in constant pitch region 173.

[0054] In some aspects, smaller or lower pitch angles may allow for a shorter sheathed length (when the pump is compressed or sheathed) which in turn will reduce sheathing delivery forces.

[0055] FIGS. 1 A to FIG 1C show the sections of the blood pump with increased flexibility and the sections of the pump with increased stiffness. Collectively, these sections of stiffness and flexibility are designed and arranged to provide for stiffness in sections that promote concentricity of the impeller within the scaffold while allowing for flexibility in sections that contact the tissue or must bend around the anatomy. Generally, the inlet and outlet sections of the blood pump are relatively stiff compared to the central section of the scaffold, the distal tip, and the catheter shaft which are relatively flexible. This allows for a load applied to the distal tip (e.g., contacting the heart wall with the distal tip) to be transferred from the distal tip to the center of the scaffold (central region 120) to prevent bending at the hub or inlet section of the pump. Thus, the central region is designed and configured to always give in first when a side load is applied to the blood pump or scaffold (e.g., contacting the anatomy). In the inlet and outlet sections, the struts can have increased width near attachment to the hubs (e.g., hubs 114a and 114b) to stiffen the scaffold in those sections. The outlet section includes stiff radial and axial elements and rigid support in the impeller bearing assembly for the cantilevered impeller and impeller shaft design to promote concentricity of impeller and scaffold and prevent the impeller from contacting the scaffold. Similarly, the inlet section can include an increase in width for distal elements to maintain the inlet and prevent collapse. Rigidity in the distal inlet section allows any potential force from distal tip to be translated to central portion of the scaffold (and not to the inlet section). The central section accommodates compound bending and pump movement while minimizing deflection to the outlet section on the proximal portion of the scaffold.

[0056] FIGS. 2A to 2E show examples of flattened scaffold patterns. In particular, FIG. 2A shows a flattened scaffold of the blood conduit of FIG. IB with an extended length from the distal end to the proximal end. The arrangement of the two rows or sets of radial elements 123c and 123d can maintain or increase stiffness of the distal portion 122 while the axial elements 121b has a length 205 configured to increase the overall length 206 of the conduit. For example, the axial element 121b length 205 may be extended between radial elements sets 123c and 123d. In some examples, axial element 121b length 205 may be between 10mm and 20 mm. For example, the length of axial element 121b length 205 may be 16mm and the conduit may have length of 70mm. Increased length of the distal portion 122 and overall length of the blood conduit can be configured to optimize placement and positioning of the pump.

[0057] Also shown in FIGS. 2A to 2C, is one or more pump position markers disposed on or in the blood conduit. As illustrated in FIG. 2 A, a plurality of pump position markers 210 may be optionally coupled to the blood conduit. The pump position markers may comprise a radiopaque material for visualization under real-time imaging or guidance such as fluoroscopy. In one example the pump position markers can comprise a material such as Platinum-Iridium (Pt-Ir). The pump position markers 210 may be arranged on the blood conduit at a length 207 from the distal end of the proximal region 118. For example, the pump position markers may be configured to indicate the length 207 from the impeller region (e.g., proximal region 118) to their markers. The length may be, for example, 24mm from the proximal region 118. The markers can also be used to indicate a length between the markers and the inlet or distal region of the blood pump. The pump markers can be used during pump placement to confirm or verify proper placement of the pump relative to the anatomy. For example, under fluoro guidance, a user or physician can align the pump position markers with an annulus of the subject, thereby placing the pump in an optimal position where the inlet is spaced a preferred distance from the annulus (and therefore the pump markers) and/or similarly the outlet is spaced a preferred distance from the annulus/pump markers. Typically, the annulus position is more easily identifiable under real-time imaging and can be registered prior to/during a procedure, so alignment of the markers with the annulus under real-time fluoro provides an efficient technique for identifying and confirming proper pump placement. [0058] The flattened scaffold pattern illustrated in FIG. 2B can be configured for increased pushability relative to the scaffold pattern of FIG. 2 A. In FIG. 2B, a width of the helical elements 229 is increased relative to the width of the helical elements in FIG. 2A, and the angle 202 of the helical elements has decreased, for example, relative to the pattern illustrated in FIG. 2A. For example, angle 202 may be 50 degrees or less in the example of FIG. 2B, whereas the example illustrated in FIG. 2A may have an increased helical element angle of up to 60 degrees. Similarly, the pattern illustrated in FIG. 2B may also reflect an increase in the width of the helicoidal struts. For example, a width of the helical elements 229 may be up to .010” compared to the helical element width of .0085” or less in the FIG. 2A embodiment. These changes in the FIG. 2B embodiment increase pushability of the FIG. 2B blood conduit while slightly reducing the flexibility of the central section relative to the FIG. 2A embodiment.

[0059] FIG. 2C illustrates another example of a scaffold pattern. In this example, there is a single set or row of distal radial elements 123c arranged in contact with axial elements in the distal region 122, compared to the two sets of radial elements 123c and 123d in the embodiments of FIGS. 2A-2B. The central region 120 in FIG. 2C is also shown having an increased length relative to the central region lengths in the FIG. 2A/2B embodiments. This increased central region length and the singular set of distal axial elements 123b can be configured to increase the flexibility and/or compliance of the blood conduit. For example, increasing the helical section (e.g., central portion 120) and removing a set of distal radial elements (e.g., as illustrated in FIGS. 2A and 2B), the blood conduit may be more flexible or less stiff. Accordingly, and as with any of the scaffold patterns illustrated herein, the overall length of the blood conduit may comprise an extended proximal region 118, central region 120, distal region 122, or a combination thereof. The helical elements of the scaffold may have a pitch or angle 202.

[0060] FIG. 2C also includes a detailed view zoomed in on examples of markers that may be directly embedded or incorporated within the blood conduit or scaffold itself. For example, the helical elements 229 in the central section 120 may include cutouts, openings, or recessed regions (e.g., opening 231) configured to receive one or more pump position markers. The cutouts, openings, or recessed regions 231 may pass partially or fully through the helical elements. In other embodiments, the pump position markers can be supported on or within the membrane that is placed over the blood conduit. In some examples, this membrane comprises a plurality of layers (e.g., an inner layer on an inside of the blood conduit and an outer layer on an outside of the blood conduit, and the plurality of markers can be embedded within the layers of the membrane. In this embodiment, the markers can be positioned between adjacent helical elements of the central section.

[0061] FIG. 2D and 2E show examples of flattened scaffold patterns of the blood conduit of FIG. 1C, including a central region that includes variable pitch regions 170 and 171 and constant pitch regions 172 and 173. Referring to FIG. 2D, the flattened presentation of the conduit 1 reveals the helical elements 129 of central region 120 extending between the proximal region 118 and the distal region 122. Variable pitch region 170 is positioned adjacent and distal to the proximal section 118 and includes helical elements 129 that transition from a first angle or pitch 175 at the proximal side of the variable pitch region to a second angle or pitch 176 at a distal side of the variable region 170. Second angle or pitch 176 is then maintained at a constant pitch or angle within constant pitch region 172. Similarly, variable region 171 includes helical elements that transition from the second angle or pitch 176 at a proximal side of variable pitch region 171 to a third angle or pitch 177 at a distal side of the variable pitch region 171. Finally, the third angle or pitch 177 can be maintained at a constant pitch or angle within constant pitch region 173. In this example, the variable regions facilitate a change from a first angle 175 to a third angle over the length of the central region. In some embodiments, the third angle and the first angle are the same. Put another way, the variable pitch regions and the constant pitch regions in some embodiments allow the helical elements to transition from a first pitch or angle near the proximal region 118 to a different pitch or angle in the central region and then to another pitch or angle at the distal region, which sometimes is the same as the pitch or angle near the proximal section. [0062] In some examples, the conduits described herein may comprise one or more variable regions. Each of the one or more variable regions may extend along a length of the conduit. A length of the variable regions may be between 1mm and 50mm. For example, a length of a variable region may be 1mm, 2mm, 3mm, 4mm. 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm or any length therebetween. In some examples, a variable region length may be greater than 50mm or less than 1mm. In some examples, the length of more than one variable region may be the same or may be different. For example, a proximal variable region may have a first length and a distal variable region may have a second length. In some examples, variable regions may be positioned anywhere on the blood conduit. For example, a variable region may be positioned adjacent to a proximal section (e.g., section 118), proximal to a distal section (e.g., 122), or anywhere in between. In some examples, the variable regions may be adjacent to one another or separated by a length of conduit with a consistent helical element angle. Referring to FIG. 2D as an illustrative example, the proximal variable region 170 extends 10mm from the proximal section 118, with a section of helical elements 20mm extending between the variable region 170 to variable region 171 having a length of 7mm and a further helical element section of 21mm extending between the distal section 122 and the variable region 171. In this example, the central portion may have a total length of 58mm between the proximal section 118 and the distal section 122.

[0063] In one specific embodiment, still referring to FIG. 2D, variable pitch region 170 includes helical elements that transition from a first angle of approximately 50° to a second angle of approximately 60°. The same second angle of approximately 60°can be maintained in constant pitch region 172. Then, in variable pitch region 171, the helical elements may transition back to approximately a 50° angle, which may be maintained in constant pitch region 173. Any of the variable regions of a blood conduit may provide, facilitate or distinguish a transition from a first angle of any degree to a second angle of any degree. [0064] FIG. 2E provides additional detail of the conduit shown in FIG. 2D. with a detailed view of the proximal struts 112a shown an example of a geometry of the struts as having paddle-shaped proximal ends 154a that are further described in FIG. 5. Similarly, a detailed section of the distal struts 112b show a distal end feature 160b that may be configured to support communication with a hub (e.g., hub 114b) of a blood pump described herein.

[0065] FIGS. 3 A to 3D show pump position markers 310 that may be optionally incorporated into or supported by the blood conduit. Referring to FIG. 3A, the blood conduit 302 has pump position markers 310 shown as a plurality of points positioned at a set distance 305 distally from the proximal region. Any example of pump position markers may include a radiopaque element or material. Some examples of pump position markers may comprise platinum-iridium material, BaSO4 material, or other radiopaque material or element. Some examples of pump position markers may be operably coupled to or integrated with the scaffold of the blood pump (e.g., as illustrated in FIGS. 2A-2E). For example, pump position markers may be a feature of the scaffold in the central region of the blood conduit. In some examples, the pump position markers may comprise a band of radiopaque material embedded into the blood conduit. For example, radiopaque bands may be embedded or otherwise incorporated into the membrane (e.g., 108) of the blood conduit. Another example of pump position markers in a band may be embedded radiopaque material in a biodurable aromatic polycarbonate-based thermoplastic urethane (e.g., chronoflex) at a position along the length of the blood conduit distal to the proximal region. In some examples, the membrane may comprise a lamination of material layers with pump position markers embedded in between layers of the membrane.

[0066] The pump position markers may be configured to indicate a position or orientation of the blood pump. For example, the pump position markers 310 shown in FIG. 3 A may be positioned at a set distance from one another around a circumference of the blood conduit. For example, there may be four pump position markers 310 arranged 90 degrees from each other around the circumference of the blood conduit. The pump position markers may also be positioned at a distance from the proximal region. For example, the pump position markers may be positioned between 20mm and 30mm (e.g., 24mm) from the impeller region of the blood pump. As illustrated in FIG. 3B, examples of pump position marker bands 300, 301, 302, 303, may be positioned at a distance (e.g., 310, 311, 312, 313) from the proximal region. Additionally, the pump position markers illustrated in FIG. 3B may be bands of radiopaque material and have a band width. For example, a width of a band may range from 2mm to 7mm.

[0067] FIGS. 3C and 3D illustrate examples of pump position markers indicating a nonlinear orientation of the blood conduit. Although not readily evident from the helical section, the pump position markers 310a are offset from pump position markers 310b, which may indicate a bend or angle of the scaffold even though, from the perspective shown, the scaffold appears linear. For example, the distal region 322 may be extending away in this position. Similarly, in FIG. 3D, pump position markers 310a and 310b are offset from one another indicating a non-linear orientation of the scaffold. For example, the scaffold may be at a 45 degree angle as indicated by the pump position marker offset.

[0068] FIG. 4 is a closeup view of outlet section 115 of the blood pump, including features that provide increased stiffness. In this figure, impeller 104 is shown supported by impeller shaft 131, which extends through impeller bearing assembly 133 that is positioned within hub 114a and terminates at a distal end of impeller (optionally just distal to the impeller blades). Generally, the structures illustrated in FIG. 4 within the proximal portion of the blood conduit can collectively be referred to as the impeller assembly. The impeller assembly can include, for example, the impeller shaft, the impeller, any distal cap or hub on the distal end of the impeller shaft, and any structures that couple or encapsulate the proximal portion of the impeller shaft to the impeller bearing assembly. In some embodiments, a distal impeller hub 107 can seal, encapsulate, or cover the impeller shaft and/or impeller blades. While the distal impeller hub is shown as a distinct element in FIG. 4, it should be understood that in some embodiments there is not a distal impeller hub or optionally the distal impeller hub is integral to the impeller shaft. The distal end of the impeller is not supported by any other features or elements and is not connected to the scaffold or to a distal end of the blood pump or conduit. There are no structures positioned within the scaffold 106 distal to the impeller assembly (e.g., the impeller, impeller shaft, and optionally the distal impeller hub). In fact, in the embodiment of FIG. 4, the impeller assembly is the only structure positioned within the blood conduit of the blood pump. The impeller 104 and impeller shaft 131 are arranged in a cantilevered design configuration in which the distal end of the impeller assembly is freely positioned within the scaffold. The position of the impeller relative to the scaffold is maintained by structures in the outlet section of the blood pump and/or the configuration of the impeller and scaffold themselves. No distal bearing is required or used. The stiffness of the impeller shaft 131 and passage of the shaft through the stiff impeller bearing assembly 133 provides the stiffness required to prevent the impeller from contacting the scaffold and blood conduit during operation in a variety of conditions. The overall design including stiffness around the impeller provides a “quiet” section around the impeller to prevent the impeller from contacting the scaffold while providing flexibility on either side of the impeller (e.g., in the catheter shaft and in the central portion of the scaffold). Preventing or limiting bending around the impeller and impeller shaft means that concentricity of the impeller and preventing contact between the impeller and the scaffold. It is further noted that in some embodiments, the proximal struts 112a can be inserted into and supported by the impeller bearing assembly 133 in section 135. The supported struts 112a adds rigidity to the outlet section 115.

[0069] In some examples, outlet section 115 in FIG. 4 and inlet section 117 illustrated in FIG. 6, of the blood pump 100 may have increased stiffness or reduced flexibility relative to other sections of the blood pump. Outlet section 115 can generally include proximal region 118 of the conduit, impeller 104, proximal struts 112a, and hub 114a. Inlet section 117 can generally include distal portion 122 of the conduit, distal struts 112b, and hub 114b. Generally, outlet section 115 and inlet section 117 are stiffer than distal shaft portion 111 of shaft 110, central region 120 of conduit 102, and distal tip section 113 of distal tip 116. [0070] Drive cable 137 extends through the shaft and is coupled to the impeller shaft 131. The drive cable can be rotated by a motor (not shown) to provide rotation to the impeller. The drive cable can be sufficiently flexible to allow for the flexibility in distal shaft portion 111 described above. The attachment of the drive cable to the impeller shaft allows for increased stiffness through the hub 114a, impeller bearing assembly 133, and impeller 104. [0071] FIG. 5 illustrates a closeup view of the ends 134a and 134b of struts 112, which may be either distal or proximal struts. In this view, it can be seen how the ends 134a alternate with ends 134b past arms 136 of the hub and into the hub body itself. For example, a paddle end 134a may be arranged on every other end of a strut 112. The paddle struts 134a can increase the engagement between the scaffold and the hub. Alternating end 134a and 134b maintains an optimal arrangement and diameter of the distal end for engagement with the hub. For example, with a preferred hub/catheter shaft diameter, and a preferred number of struts and strut thicknesses, placing the paddle distal ends on only a subset of the struts allow for maximum hub engagement and proximal strut stiffness while still satisfying diameter requirements of the hub and catheter shaft. Extension of the struts into the hub body increases stiffness of the hub (and therefore the inlet section) and can prevent buckling or bending at the strut/arm transition when large forces are applied to the blood pump (e.g., to the distal tip).

[0072] FIG. 6 shows a cross-sectional view of inlet section 117 and its connection to the distal tip 116, including flexible distal tip section 113. As described above, the flexible distal tip section 113 can be configured and designed to have increased flexibility by adjusting or changing the wall thickness within the tip. The distal tip 116 can include a guidewire lumen 140 that extends from the inlet section through the distal tip. The guidewire lumen can be configured to accommodate and receive a guidewire during positioning of the blood pump in the anatomy. As shown in FIG. 6, the guidewire lumen can include a junction 142 either within the hub 114b or at the transition from the hub to the distal tip section 113 in at which the diameter of the guidewire lumen changes. As shown, the diameter of the guidewire lumen within the hub 114b is smaller than the diameter of the guidewire lumen within the distal tip section 113. In the illustrated embodiment, the diameter of the guidewire lumen transitions from the first (smaller) diameter in the hub to the second (larger) diameter in the distal tip section. This results in a larger wall thickness in the hub, resulting in more stiffness in the hub, compared to a smaller wall thickness in the distal tip, resulting in less stiffness in the distal tip. In addition to using wall thickness to make the distal tip more flexible, the distal tip 116 can also comprise a material of reduced durometer to increase flexibility in the distal tip section 113.

[0073] It is important to maintain a minimum distance between the rotating impeller 104 and the inside surface of the blood conduit 102 so that the impeller blades do not contact the inside surface of the blood conduit while they are rotating. When the blood conduit 102 extends in a straight line, as shown in FIG. 7A, the impeller’s longitudinal axis is centered on the longitudinal axis of the blood conduit, and the gap between the rotating impeller blades and the inside surface of the blood conduit remains substantially constant. When the blood conduit 102 is disposed in a position requiring it to bend (such as, e.g., when the blood pump extends from the left ventricle through the aortic valve into the ascending aorta), the inside surface of the blood conduit may move closer to one side of the distal portion of the impeller 104, as shown in FIG. 7B. The collective features described herein and above allow for the blood pump of the present disclosure to prevent the impeller 104 from contacting the scaffold even when loads are applied to the pump, causing bending or deformation in various sections of the pump. As described above, preferential bending and flexibility in the distal tip, central portion of the scaffold, and distal shaft portion of the shaft, combined with stiffness in the inlet section and outlet section of the blood pump, allow the cantilevered impeller 104 to prevent the impeller 104 from contacting within the blood conduit scaffold.

[0074] Blood conduits described herein may comprise a scaffold pattern including elements of a scaffold that may be adapted for increased flexibility (e.g., navigability) of the blood conduit. For example, one or more regions of the scaffold may comprise one or more struts configured to provide increase or decrease or combination thereof to the curvature or flexibility of the blood conduit.

[0075] FIG. 8A and FIG. 8B show another example of a blood conduit having a variable strut region 350 positioned between the proximal region 118 and the distal region 122 of the conduit (e.g., within the central region). In FIG. 8A, the variable strut region can extend from proximal end 356 of the variable strut region to distal end 357 of the variable strut region. [0076] In one embodiment, a thickness of one or more struts 355 can vary within the variable strut region. For example, the struts 355 may have a first thickness at or near proximal end 356 of the variable strut region and a second thickness at or near distal end 357 of the variable strut region. In some examples, the struts may be wider/thicker near the proximal end 356 than they are at the distal end 357. In some embodiments, the thickness of the struts can gradually decrease along the length of the variable strut region (e.g., the width of the struts can decrease as the struts extend distally away from the proximal region 118). [0077] In another embodiment, a pitch or angle of the struts 355 can be increased within the variable strut region. For example, the struts 355 may have a first pitch at or near proximal end 356 of the variable strut region and a second pitch at or near distal end 357 of the variable strut region. In some examples, the pitch of the struts at the proximal end 356 may be lower than the pitch of the struts at the distal end 357. In some embodiments, the pitch of the struts can gradually increase along the length of the variable strut region (e.g., the pitch of the struts can increase as the struts extend distally away from the proximal region 118).

[0078] In some embodiments, both the thickness of the struts, and the pitch of the struts can vary across the variable strut region. For example, the thickness of the struts may decrease between proximal end 356 and distal end 357, while the pitch of the struts may also increase over this same distance.

[0079] The change in strut thickness/pitch described above allows for the variable strut region to be configured to soften a bend radius of the scaffold pattern within this region, which can increase flow and help hemolysis when the pump is in a bent configuration.

[0080] Referring to FIG. 8 A, the variable strut region 350 is illustrated adjacent to the proximal region 118. However, a blood conduit may have a variable region at one or more lengths of the blood conduit between the proximal end and the distal end. The position of the variable region 350, as shown, can provide a softer or less drastic bend radius when the pump is bent, particularly in the region adjacent to one or more impellers of the catheter blood pump. For example, the bend radius at a variable region may be configured to increase flow and aid hemolysis when the pump is in a bent configuration.

[0081] FIG. 8B illustrates an example of a flattened scaffold pattern including the proximal region 118 and the adjacent variable strut region 350. In this flattened scaffold patten view, details of the helical elements 355 within the variable strut region 350 are provided with each element in this section extending between proximal end 356 adjacent to the proximal region 118 to the distal end 357.

[0082] In FIG. 8B, the struts 355 may have a first thickness 361 near a proximal end 356 of the variable strut region and a second thickness near the proximal end 357 of the variable strut region. In one example, the first thickness is greater than the second thickness (i.e., the helical element thickness decreases as the helical element extend distally from the proximal end). In other embodiments, the helical element thickness can increase along the variable strut region. The change in helical element thickness along the variable strut region can be constant, or instead the change from the first thickness to the second thickness can occur in one or more sudden increases/decreases. In some examples, the thickness of the helical element can change by up to 25%, up to 35%, up to 45%, or up to 50% along a length of the variable strut region. In one specific example, the first thickness can be approximately 0.012” and the second thickness can be approximately 0.0085” (e.g., a reduction in thickness by approximately 33%).

[0083] Pitch angles of the struts 355 within the variable strut region are also shown with a first pitch angle 360 near the proximal end 356 and a second pitch angle 365 near the distal end 357. In one example, the first pitch angle is smaller than the second pitch angle (i.e., the pitch angle increases as the struts extend distally from the proximal end). In other embodiments, the pitch angle can decrease along the variable strut region. The change in pitch angle along the variable strut region can be constant, or instead the change from the first pitch angle to the second pitch angle can occur in one or more sudden increases/decreases. In some examples, the pitch angle can change by up to 5%, up to 10%, up to 20%, up to 25%, or up to 33% along a length of the variable strut region. In one specific example, the first pitch angle can be approximately 50 degrees and the second pitch angle can be approximately 60 degrees (e.g., an increase in pitch angle by approximately 20%).

[0084] The length of the variable strut region can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 20mm or more or any length therebetween. For example, the variable strut region may be 10mm as illustrated in FIG. 8 A. In some examples, the variable strut region can comprise a specified percentage of the overall length of the catheter blood pump blood conduit. For example, some embodiments may include a blood conduit with a length of 60mm and a variable strut region of 10mm, where the variable strut region comprises approximately 16% of the length of the blood conduit. In other embodiments, the blood conduit length may be 70mm with the variable strut region being 10mm, or approximately 14% of the length of the blood conduit. According to the present disclosure, the variable strut region may comprise between 10 and 25% of the length of the blood conduit of a blood catheter pump.

[0085] The thickness of the strut may decrease from an initial thickness (e.g., an initial thickness of .009”, .010”, .011”, .012”, .013”, .014”, .015”, .016”, .017”, .018”, .019”, .020”, or more or less or any thickness therebetween) to a decreased thickness at the end of the a variable pitch region (e.g., a decreased thickness of .0050”, .0055”, .0060”, .0065”, .0070”, .0075”, .0080”, .0085”, .0090”, .0095”. or less or more or any thickness therebetween).

[0086] In some examples, a variable strut region may comprise a change in the helical element angle (e.g., pitch angle) from the proximal end of the variable strut region (e.g., adjacent to the proximal region of the blood conduit) to the distal end of the variable strut region. The angle may change from an initial angle at the proximal end of the variable strut region (e.g., an initial angle of 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or more or less or any angle therebetween) to an angle at the distal end of the variable strut region greater than the initial angle (e.g., a variable pitch region distal angle of 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, or more or less of any angle therebetween. For example, the initial pitch angle of the variable strut region may be 50 deg and increase to a distal angle of 60 deg, as illustrated in FIG. 8B.

[0087] FIG. 9A to FIG. 9C illustrate examples of the blood conduit from FIG. 8A in bent configurations with different arch radii as facilitated by the variable strut region 350. From these examples, the bend as facilitated by the variable strut region can be appreciated. The bend radius may increase or decreasing from the distal end to the proximal end. Referring to FIGS. 9A to 9C, the bend radius is shown generally positioned proximal of a midline of the blood conduit (e.g., at the variable strut region) and may be increased or decreased based on the variable pitch region attributes (e.g., strut thickness, variable pitch region length, helix angle or combination thereof). In some examples, the function of the variable pitch region is to facilitate a bent configuration of the blood conduit. For example, a bent configuration may be measurable and include a pump angle, radius (e.g., bend radius), and distance from the impeller to the bend. Some examples of bent configuration measurements as facilitated by a variable pitch region may include a pump angle of 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160° or more or less or any degree therebetween. Some examples of bent configuration measurements as facilitated by a variable pitch region may include a radius of 1mm, 5mm, 10mm, 15mm, 20mm, or more or less or any radius therebetween. Some examples of bent configuration measurements as facilitated by a variable pitch region may include a distance from the impeller to the bend being 1mm, 5mm, 10mm, 15mm, or more or less or any distance therebetween.

[0088] FIG. 10 illustrates an example of a blood pump including the blood conduit 102 in position with a vessel 375 as the variable strut region 350 is facilitating the curvature and bent configuration as the blood pump is navigated or positioned within the vessel. In this example of the blood pump within the vessel 375, the variable strut region is configured to soften a bend radius of the scaffold pattern within this variable strut region, adjacent to the proximal region 118 which may include a proximal impeller, which can increase flow through the pump and help hemolysis when the pump is in this bent configuration within the anatomy.

[0089] It should be understood that any feature described herein with respect to one embodiment can be substituted for or combined with any feature described with respect to another embodiment. [0090] When a feature or element is herein referred to as being “on” another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being “directly on” another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being “connected”, “attached” or “coupled” to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being “directly connected”, “directly attached” or “directly coupled” to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.

[0091] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.

[0092] Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “undef ’ can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms “upwardly”, “downwardly”, “vertical”, “horizontal” and the like are used herein for the purpose of explanation only unless specifically indicated otherwise. [0093] Although the terms “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.

[0094] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

[0095] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word “about” or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, 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. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0096] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

CLAIMS What is claimed is:

1. A catheter blood pump comprising an expandable shroud forming a blood conduit, the shroud having a distal section, a proximal impeller section, and a central section between the distal section and the proximal impeller section, wherein the central section comprises a plurality of helically winding scaffold elements, wherein at least one of a pitch angle and a strut thickness of the helically winding scaffold elements varies along a transitional portion of the central section; and an impeller disposed at least partially within the proximal impeller section.

2. The catheter blood pump of claim 1, wherein the transitional portion is adjacent to the proximal impeller section.

3. The catheter blood pump of claim 1, wherein the strut thickness of the helically winding scaffold elements decreases from first thickness to second thickness along the transitional portion.

4. The catheter blood pump of claim 3, wherein the strut thickness of the helically winding scaffold elements decreases from a proximal side of the transitional portion to a distal side of the transitional portion.

5. The catheter blood pump of claim 1, wherein the pitch angle of the helically winding scaffold elements increases from a first angle to a second angle along the transitional portion.

6. The catheter blood pump of claim 1, wherein the pitch angle of the helically winding scaffold elements increases from a proximal side of the transitional portion to a distal side of the transitional portion.

7. The catheter blood pump of claim 1, wherein the pitch angle of the helically winding scaffold elements increases at a ratio of approximately 1 : 1.2.

8. The catheter blood pump of claim 1, wherein the pitch angle of the helically winding scaffold elements increases 120% from a proximal side of the transitional portion to a distal side of the transitional portion.

9. The catheter blood pump of claim 1, wherein the pitch angle increases 10° from a proximal side of the transitional portion to a distal side of the transitional portion.

10. The catheter blood pump of claim 1, wherein the transitional portion is stiffer than a remainder of the central section.

11. The catheter blood pump of claim 1, further comprising a constant pitch portion distal to the transitional portion in which the pitch angle of the plurality of helically winding scaffold elements

12. The catheter blood pump of claim 11, wherein the transitional portion comprises a first transitional portion, the catheter blood pump further comprising a second transitional portion distal to the constant pitch portion.

13. The catheter blood pump of claim 12, wherein at least one of the pitch angle and the strut thickness of the helically winding scaffold elements varies along the second transitional portion.

14. The catheter blood pump of claim 13, wherein the pitch angle of the helically winding scaffold elements varies from a first pitch angle to a second pitch angle along the first transitional portion, and varies from the second pitch to a third pitch angle along the second transitional portion.

15. The catheter blood pump of claim 14, wherein the first pitch angle is substantially similar to the third pitch angle.

16. The catheter blood pump of claim 15, wherein the strut thickness of the helically winding scaffold elements reduces along the first transitional portion and increases along the second transitional portion.

17. A catheter blood pump comprising an expandable shroud forming a blood conduit, the shroud having a distal section, a proximal impeller section, and a central section between the distal section and the proximal impeller section, wherein the central section comprises a helical pattern with at least one variable pitch region positioned in the central section in which helical elements of the blood conduit transition from a first pitch angle to a second pitch angle.

18. The catheter blood pump of claim 17, wherein a flexibility of the variable pitch region increases distally along the variable pitch region.

19. The catheter blood pump of claim 17, wherein a strut thickness of the helical elements decreases from a proximal side of the variable pitch region to a distal side of the variable pitch region.

20. The catheter blood pump of claim 17, wherein the pitch angle of the helical elements increases across the variable pitch region.

21. The catheter blood pump of claim 17, wherein the variable pitch region is adjacent to the proximal impeller section.

22. The catheter blood pump of claim 17, wherein the variable pitch region comprises a first variable pitch region, and wherein the catheter blood pump further comprises a second variable pitch region.

23. The catheter blood pump of claim 22, wherein the helical elements transition from the second pitch angle to a third pitch angle in the second variable pitch region.

24. The catheter blood pump of claim 23, wherein the first pitch angle is substantially similar to the second pitch angle.

25. A catheter blood pump, comprising: a flexible catheter; a blood pump portion coupled to a distal end of the flexible catheter, the blood pump portion comprising: an expandable and collapsible scaffold forming an inlet portion, and outlet portion, and a flexible central portion disposed between the inlet portion and the outlet portion, the flexible central portion comprising a plurality of helical elements having a pitch angle that varies along specified portions of the flexible central portion; a blood impermeable membrane disposed on the scaffold and forming a blood conduit between the inlet portion and the outlet portion; and an impeller disposed within the conduit near or partially within the outlet portion; a flexible distal tip coupled to a distal end of the blood pump portion.