Flexible outflow cannula with a formed outlet

Abstract

A blood pump can be provided that can include a pump housing and a catheter operably coupled to the pump housing. The pump can include a flexible outflow cannula having a proximal portion operably coupled to the catheter, a blood flow outlet, and a distal portion operably coupled to the pump housing. The proximal portion of the flexible outflow cannula can have a connection portion coupled to the catheter and a non-connection portion extending distally from the connection portion, and at least one slit can be formed through the entire connection portion. The slit can extend distally from the connection portion through at least a portion of the non-connection portion and connect to the proximal end of at least one of the blood flow outlets ("cutoff outlets"), and the cutoff outlets have a tapered proximal end and extend distally from the non-connection portion.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 355,217, filed on June 24, 2022, the content of which is incorporated herein by reference in its entirety.

[0002] Technical Field The present disclosure relates to a blood pump outflow cannula having a shaped (such as V - shaped) outlet.

Background Art

[0003] Background A blood pump that may use an outflow cannula is used to ensure that blood moves around obstructions, valves, etc. from one part of the human body to an adjacent part. For example, a blood pump can be used to move blood from the left ventricle through the aortic valve.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as the size of the blood pump is reduced, two problems arise. That is, being able to manufacture a device that is further miniaturized, and on the other hand, ensuring that the device does not promote thrombus formation.

Means for Solving the Problems

[0005] Summary In various aspects, a blood pump can be provided. The blood pump includes a pump housing having a blood flow inlet, a catheter operably connected to a proximal end of the pump housing, and a flexible outflow cannula having a proximal portion operably connected to the catheter, a plurality of blood flow outlets, and a distal portion operably connected to the pump housing, wherein the pump housing and the flexible outflow cannula can define a blood flow path from the blood flow inlet of the pump housing to the plurality of blood flow outlets, and an impeller disposed within the pump housing and configured to be rotatable about a rotation axis to convey blood from the blood flow inlet to the plurality of blood flow outlets.

[0006] The catheter can have an outer diameter smaller than the outer diameter of the pump housing. The proximal portion of the flexible outflow cannula can have a connecting portion connected to the catheter and a non-connected portion extending distally from the connecting portion. At least one slit can be formed to penetrate the entire connecting portion and extend to the proximal end of the flexible outflow cannula. The plurality of blood flow outlets can include at least one cut-off outlet, and the slit can extend distally from the connecting portion through at least a part of the non-connected portion and connect to the proximal end of at least one of the cut-off outlets. The cut-off outlet can have a tapered proximal end and extend distally from the non-connected portion.

[0007] In some embodiments, the plurality of blood flow outlets consists of four blood flow outlets, and the four blood flow outlets consist of exactly one cut-off outlet or exactly two cut-off outlets. In some embodiments, each of the plurality of blood flow outlets can be spaced circumferentially equally apart from an adjacent blood flow outlet. In some embodiments, the cut-off outlet consists of one cut-off outlet.

[0008] In some embodiments, the flexible outflow cannula can include an intermediate portion extending between a distal end portion and a proximal end portion, and the intermediate portion can have an outer diameter that may be larger than the outer diameter of the pump housing.

[0009] In some embodiments, each of the plurality of blood flow outlets can be at least partially positioned in the middle portion, and only the cutout outlet is at least partially positioned in both the proximal end portion and the middle portion.

[0010] In some embodiments, the flexible outflow cannula can be defined by a substantially tubular member having a side wall thickness of less than 20 microns.

[0011] In some embodiments, each cutout outlet can include a distal portion, a proximal portion, and a middle portion between the distal portion and the proximal portion, and the middle portion has substantially parallel sides. In some embodiments, the proximal portion of the cutout outlet forms a notch having linearly non-parallel sides. In some embodiments, the proximal portion of the cutout outlet forms a notch having concave sides. In some embodiments, the proximal portion of the cutout outlet forms a notch having convex sides. In some embodiments, the proximal end of the proximal portion can have a width equal to the width of the slit across the connecting portion. In some embodiments, the proximal end of the proximal portion can have a width that may be greater than the width of the slit across the connecting portion.

[0012] In some embodiments, the slit can be configured to allow at least a first portion of the connecting portion of the proximal end portion to overlap a second portion of the connecting portion of the proximal end portion. In some embodiments, the slit can be configured to prevent a first portion of the connecting portion of the proximal end portion from overlapping a second portion of the connecting portion of the proximal end portion.

[0013] In some embodiments, the blood pump can include a filter that is in fluid communication between (a) the internal volume of the blood vessel into which the blood pump can be inserted outside the pump housing and (b) the blood flow inlet, the filter comprising a plurality of generally helical first struts wound about a longitudinal axis and a plurality of second struts, the first struts and the second struts together defining a plurality of apertures therebetween.

[0014] In some embodiments, the pump housing, the impeller, and any filter can each be radially compressible and radially expandable alternately.

[0015] In some embodiments, the pump housing can be configured to elongate longitudinally by an amount determined by the amount by which the pump housing can be radially compressed when radially compressed, and the filter can be configured to elongate longitudinally by an amount determined by the amount by which the filter can be radially compressed when radially compressed, such that for a given amount of radial compression, the filter and the pump housing elongate longitudinally by approximately equal amounts.

[0016] In some embodiments, the catheter, the pump housing, the impeller, and the filter are configured for use in a living patient, and each aperture of the plurality of apertures can be sized to prevent suction of the heart tissue of the living patient by the blood flow inlet.

[0017] In some embodiments, each aperture of the plurality of apertures can have a maximum dimension of about 0.5 mm or less. In some embodiments, each aperture of the plurality of apertures can have a maximum dimension of about 0.4 mm or less. In some embodiments, each aperture of the plurality of apertures can have an area of about 0.09 mm 2 or less. In some embodiments, each aperture of the plurality of apertures can have an area of about 0.16 mm 2 or less. In some embodiments, the plurality of apertures can have a size that monotonically increases along the longitudinal axis.

[0018] In some embodiments, generally helical first struts can be wound clockwise about a longitudinal axis, and second struts are generally helically wound counterclockwise about the longitudinal axis. In some embodiments, generally helical first struts can be wound in a first direction about a longitudinal axis, and second struts are generally helically wound in the first direction about the longitudinal axis. In some embodiments, each strut of at least a subset of the second struts can be positioned within a respective plane that includes the longitudinal axis. In some embodiments, each aperture of at least a subset of the plurality of apertures can have a generally rhombic or skew-rhombic shape. In some embodiments, generally helical first struts can include a plurality of first filaments, second struts can include a plurality of second filaments, and the first and second filaments can be woven together to define a plurality of apertures between respective adjacent first and second woven filaments. In some embodiments, the filter can include a tube having a wall, and the plurality of apertures can include a plurality of openings defined through the wall. In some embodiments, the tube can include a generally funnel-shaped tube. In some embodiments, the wall can have a thickness of about 10 to 100 μm.

[0019] In some embodiments, the pump housing can include a plurality of third struts that together define a plurality of third apertures therebetween, and at least some of the first and second struts are radially aligned on respective ones of the third struts.

[0020] In some embodiments, each strut of at least a subset of the first struts can include a fork that includes a plurality of teeth, and the plurality of first struts and the plurality of second struts can extend between pairs of teeth and together can define a plurality of apertures therebetween. In some embodiments, each first strut that includes a fork can be wider than each first strut that does not include a fork.

[0021] In some embodiments, the plurality of apertures can be arranged in a plurality of circumferentially generally equally sized rows of apertures generally circumferential with respect to the longitudinal axis, and one or more of the rows can have a different number of apertures than the other rows of the rows.

[0022] In some embodiments, a first row of the plurality of generally circumferential rows can include more apertures than a second row of the plurality of generally circumferential rows, and each aperture of the first row can have a smaller area than each aperture of the second row.

[0023] In some embodiments, the apertures can be arranged in a plurality of bands of apertures generally circumferential with respect to the longitudinal axis and generally equal in size, and the size of the apertures in each of the plurality of bands monotonically increases along the longitudinal axis.

[0024] In some embodiments, the filter can include a distal portion and a proximal portion, the distal portion can monotonically increase in diameter in the proximal direction along the longitudinal axis, the proximal portion can monotonically decrease in diameter in the proximal direction along the longitudinal axis, and at least a portion of the plurality of apertures can be disposed in the distal portion.

[0025] In some embodiments, the generally helical first struts and second struts may not have any struts circumferential with respect to the longitudinal axis.

[0026] Brief Description of the Drawings The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

Brief Description of the Drawings

[0027]

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DETAILED DESCRIPTION OF THE INVENTION

[0028] It should be understood that the accompanying drawings are not necessarily to scale and present somewhat simplified representations of various features illustrative of the basic principles of the invention. For example, specific design features of a series of operations as disclosed in the specification, including the specific dimensions, orientation, position, and shape of various illustrated components, are in part determined by the particular intended use and operating environment. Some features of the illustrated embodiments are enlarged or distorted relative to other features to facilitate visualization and clear understanding. In particular, for example, thin features may be thickened for clarity or illustration.

[0029] DETAILED DESCRIPTION The following description and drawings merely illustrate the principles of the present invention. Accordingly, those skilled in the art will understand that although not explicitly described or illustrated herein, various arrangements can be devised that embody the principles of the present invention and are within its scope. Further, all examples enumerated herein are explicitly intended to be merely illustrative for the purpose of helping the reader understand the principles of the present invention and the concepts contributed by the inventors to promote the art, and should not be construed as limited to such specifically enumerated examples and conditions. Further, the term "or" as used herein refers to a non-exclusive or unless otherwise indicated (e.g., "otherwise" or "or alternatively"). Also, since some embodiments can combine with one or more other embodiments to form new embodiments, the various embodiments described herein are not necessarily mutually exclusive.

[0030] Many of the innovative teachings of this application will be described with particular reference to presently preferred exemplary embodiments. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. Generally, the descriptions in the specification of this application do not necessarily limit any of the various inventions recited in the claims. Further, some descriptions may apply to some inventive features but may not apply to others. Those skilled in the art who obtain information from the teachings herein will understand that this disclosure is applicable to various other technical fields or embodiments.

[0031] For example, a blood pump with a specific flexible outflow cannula can be provided to improve manufacturability and minimize the risk of thrombus formation in a small blood pump.

[0032] Referring to FIG. 1, an embodiment of the blood pump 10 can include a pump housing 20. The pump housing can have a blood flow inlet 25. The blood pump can include a catheter 30 operably coupled to the proximal end of the pump housing.

[0033] The blood pump can include a flexible outflow cannula 40 having a proximal portion 42 operably coupled to the catheter, a plurality of blood flow outlets 50, 60, and a distal portion 41 operably coupled to the pump housing. The pump housing and the flexible outflow cannula can define a blood flow path from the blood flow inlet of the pump housing to the plurality of blood flow outlets.

[0034] An impeller 70 can be disposed within the pump housing and configured to be rotatable about a rotational axis to convey blood from the blood flow inlet to the plurality of blood flow outlets.

[0035] Referring to FIG. 2, a top view of the flexible outflow cannula can be seen. In a preferred embodiment, the flexible outflow cannula can be defined by a substantially tubular member having a sidewall thickness of less than 20 microns. In some embodiments, the sidewall thickness can be 30 microns or less. In some embodiments, the sidewall thickness can be 18 microns or less. In some embodiments, the sidewall thickness can be 17 microns or less. In some embodiments, the sidewall thickness can be 16 microns or less. In some embodiments, the sidewall thickness can be 15 microns or less. In some embodiments, the sidewall thickness can be 10 microns or less. As can be seen, in some embodiments, the catheter 30 can have an outer diameter 31 that can be smaller than the outer diameter 21 of the pump housing 20.

[0036] In some embodiments, the flexible outflow cannula can include an intermediate portion 43 extending between the distal portion 41 and the proximal portion 42. The intermediate portion can have an outer diameter 44 that is larger than the outer diameter 21 of the pump housing.

[0037] The proximal portion 42 of the flexible outflow cannula can have a connecting portion 45 connected to the catheter 30 and a non-connected portion 46 extending distally from the connecting portion.

[0038] At least one slit 80 can be formed that extends through the entire connecting portion 45 and extends to the proximal end of the flexible outflow cannula.

[0039] As used herein, "slit" refers to a boundary or opening between adjacent members of a connecting portion that is divided (or has been divided) in some way (e.g., using a laser, a punching die, scissors, etc.). There may be some separation or a volume of empty space between two adjacent members. The two adjacent members may overlap. The two adjacent members may be connected in some other way such that there is no separation or volume of empty space separating the adjacent members. In some embodiments, the two adjacent members are separated by a distance greater than 1 micron. In some embodiments, the two adjacent members are separated by a distance less than 1 micron. In some embodiments, the two adjacent members are in contact with each other.

[0040] In some embodiments, only a single slit may be present. In some embodiments, two slits may be present. In some embodiments, when two slits are present, they can be located on both sides of the outflow cannula (e.g., located 180 degrees around the central axis of the outflow cannula).

[0041] In some embodiments, the blood flow outlets 50, 60 can include one or more extraction outlets 60, and the slit can be connected to the proximal end of at least one of the extraction outlets. In some embodiments, the slit can be connected to the proximal end of the extraction outlet 60 at the proximal end of the non-connected portion 46. In some embodiments, the slit can extend distally through at least a portion of the non-connected portion from the connecting portion and be connected to the proximal end of the extraction outlet.

[0042] The cut-out outlet can extend distally from the unconnected portion and can have a tapered proximal portion 62.

[0043] In some embodiments, the plurality of blood flow outlets consists of four blood flow outlets 50, 60, and the cut-out outlet 60 consists of one or two of those four outlets. In some embodiments, the plurality of blood flow outlets can include four blood flow outlets 50, 60, and only one of them may be the cut-out outlet 60. In some embodiments, each of the plurality of blood flow outlets 50, 60 may be spaced circumferentially equally apart from an adjacent blood flow outlet. That is, if there are three outlets, the center line of each outlet (e.g., an imaginary line extending from the proximal end to the distal end of each outlet that bisects the cross-sectional area of the outlet) may be offset 120 degrees from an adjacent outlet. If there are four outlets, the center lines may be offset by 90 degrees, and for five outlets, they may have a 72-degree offset, and so on.

[0044] In some embodiments, each of the plurality of blood flow outlets 50, 60 can be at least partially positioned in the middle portion 43 of the outflow cannula, and only the cut-out outlet 60 is at least partially positioned in both the proximal portion 42 of the outflow cannula and the middle portion 43 of the outflow cannula.

[0045] Referring to FIG. 3A, in some embodiments, each cut-out outlet can include a distal portion 61 and a proximal portion 62. Each cut-out outlet can include an intermediate portion 63 between the distal portion and the proximal portion. In some embodiments, the intermediate portion can have substantially parallel sides 64.

[0046] The shape of the proximal portion can vary. For example, in some embodiments, the proximal portion 62 can form a notch that is linear but has non-parallel sides (FIGS. 3A and 3B).

[0047] In some embodiments, the non-parallel sides form a V-shaped cut (see FIG. 3A). In some embodiments, the width 65 of the cut at the proximal end may be equal to the width of the slit 80 connected to the cut. In some embodiments, the width 65 of the cut at the proximal end may be smaller than the width of the slit 80 connected to the cut. In some embodiments, the width 65 of the cut at the proximal end may be 1 mm or less. In some embodiments, the width 65 of the cut at the proximal end may be 500 microns or less. In some embodiments, the width 65 of the cut at the proximal end may be 250 microns or less. In some embodiments, the width 65 of the cut at the proximal end may be 125 microns or less. In some embodiments, the width 65 of the cut at the proximal end may be 50 microns or less. In some embodiments, the width 65 of the cut at the proximal end may be 25 microns or less. In one embodiment, the width 65 of the cut at the proximal end may be 10 microns or less.

[0048] In some embodiments, the non-parallel sides may form a trapezoidal cut (see FIG. 3B). In some embodiments, the width 65 of the cut at the proximal end may be larger than the width of the slit 80, but smaller than the width 66 of the middle portion 63 of the cut. In some embodiments, the proximal portion may form a cut having concave sides (see FIG. 3C). In some embodiments, the proximal portion may form a cut having convex sides (see FIGS. 3D, 3E).

[0049] In some embodiments, the proximal end of the cut may be substantially a point (see FIGS. 3A, 3C, 3D). In some embodiments, the proximal end of the cut may be a square or flattened end (see FIG. 3B). In some embodiments, the proximal end of the cut may be rounded (see FIG. 3E).

[0050] Referring to FIG. 4A, in some embodiments, the slit 80 can be configured such that at least a first portion 47 of the connecting portion 45 can overlap a second portion 48 of the connecting portion. Referring to FIG. 4B, in some embodiments, the slit 80 can be configured to prevent a first portion of the connecting portion of the proximal end portion from overlapping a second portion of the connecting portion of the proximal end portion.

[0051] In some embodiments, the pump housing, the impeller, and the filter can each be compressible radially and expandable radially, alternately.

[0052] FIG. 5 is a partial cutaway view of an expandable blood pump 100 positioned within the left ventricle 102 of a patient's heart 104. In other uses, the expandable blood pump 100 may be positioned at other locations within the patient's body, such as within the left atrium or at other locations within the patient's vascular system that are not necessarily within the heart 104. The blood pump 100 can include a catheter 106 and a pump section 108 disposed at or near an end of the catheter 106.

[0053] The catheter 106 can be configured to be inserted into a blood vessel, such as the aorta 110, that defines an internal volume 112 through which blood flows in a blood flow direction 114 (illustrated here by an arrow indicating an exemplary direction). As used herein, the term "blood vessel" includes a heart chamber or other lumen. The catheter 106 can be connected to a controller 116, such as an Automatic Impella Controller ("AIC") available from Abiomed, Inc. The controller 116 can provide a user interface for controlling and monitoring the intravascular blood pump 100.

[0054] As shown by the arrows (distal 198, proximal 199) in FIG. 5, as used herein, the term "distal" refers to the direction or position along the catheter 106 away from the controller 116 or the user of the controller 116, and the term "proximal" refers to the direction or position along the catheter 106 toward the controller 116 or the user of the controller 116.

[0055] During insertion, as shown in FIG. 5, the intravascular blood pump 100 can be positioned to extend through the aortic valve 118. However, in other uses, the intravascular blood pump 100 may be positioned not necessarily within the heart 104 but at other locations in the patient's vasculature. Further, FIG. 5 shows the intravascular blood pump 100 inserted such that the blood flow direction 114 can be away from the distal end of the catheter 106. However, in other uses, the intravascular blood pump 100 may be inserted such that the blood flow direction 114 can be toward the distal end of the catheter 106. For example, the intravascular blood pump 100 may be inserted from the left atrium through the mitral valve into the left ventricle 102. In the use shown in FIG. 5, the valve leaflets of the aortic valve 118 close around the intravascular blood pump 100.

[0056] The intravascular blood pump 100 can be placed inside the heart 104 using percutaneous, transcatheter techniques. For example, the intravascular blood pump 100 can be introduced from the femoral artery (not shown). However, alternative vascular accesses such as access from the subclavian artery may also be possible. After passing through the femoral artery, the catheter 106 can be pushed into the aorta 110 such that the pump section 108 reaches inside the heart 104 through the aortic valve 118. The positioning of the pump section 108 in FIG. 5 serves merely as an example, and different arrangements such as positioning the pump section 108 inside the right ventricle of the heart 104 are also possible.

[0057] For example, a flexible atraumatic tip 120 having a pigtail or J-shaped configuration extends distally from the distal end of the pump section 108. The atraumatic tip 120 should be sufficiently soft so that the pump section 108 can contact the inner wall of the left ventricle 102 and support itself atraumatically.

[0058] The pump section 108 includes an impeller (not shown) disposed inside the housing 122. The housing 122 and the impeller are not necessarily essential but can be made expandable. The impeller can be mechanically coupled to an external motor 124 via a flexible drive shaft (reference number 202, not shown in this figure) that extends through the catheter 106. The motor 124 may be within the controller 116 or in other locations. Alternatively, the impeller may be mechanically coupled to a motor (not shown) disposed within the pump section 108 via a relatively short drive shaft (not shown). In either case, the motor rotates the impeller via the drive shaft to cause blood from the internal volume 112, as indicated by the arrow, to flow from the blood flow inlet (input port) 126 at the distal end of the pump section 108 to the blood flow outlet (output port) 128 located proximal to the blood flow inlet 126. As described above, the term "internal volume" 112 includes a cardiac chamber such as the left ventricle 102.

[0059] A filter 130 can be disposed to provide fluid communication between (a) a blood vessel external to the pump housing 122, in this case the internal volume 112 of the left ventricle 102, and (b) the input port 126. The filter 130 is described in connection with the expandable housing 122 and the impeller, but the filter 130 may be used with a non-expandable housing 122 and impeller as well.

[0060] The struts 300 - 304 used in the filter can be made of wire or other filaments. As shown in FIGS. 6 and 7, the housing 122 can provide a cage around the impeller 200. When radially expanded (FIG. 6), the length 306 of the housing 122 can be made smaller than the length 400 when the housing 122 is radially compressed (FIG. 7). The change from length 400 to 306 can be due to the struts 300 - 304 loosening when the housing 122 expands. In some embodiments, the change from length 400 to length 306 can be about 1 - 2 mm.

[0061] The expandable housing 122, expandable impeller 200, and expandable filter 130 can be maintained in their compressed state by a suitable compression sleeve 308 that slides over the expandable housing 122, expandable impeller 200, and expandable filter 130. The intravascular blood pump 100 comprising the expandable housing 122, expandable impeller 200, and expandable filter 130 can be transported through the patient's vasculature while the housing 122, impeller 200, and filter 130 are in the compressed state. When the pump section reaches its target location, the housing 122, impeller 200, and filter 130 can be allowed to expand, for example, by pushing the pump section 108 forward (distal direction) from the compression sleeve 308 or by pulling back the compression sleeve 308 (in the proximal direction). With the compression sleeve 308 removed, the housing 122 expands due to its shape memory, superelastic, or hyperelastic properties, as shown in FIG. 6. At the same time, the impeller 200 also expands due to its elasticity. When the housing 122 expands in a direction radially away from the drive shaft 202, the housing 122 may contract longitudinally to a length 306.

[0062] The inner central portion of the housing 122 can have a sleeve or coating 310 (best seen in FIG. 14) that defines a channel through which blood can be pumped by the impeller 200. Proximal and distal to this channel, the housing 122 can allow blood to be drawn into the housing 122 and pushed out into the outflow cannula from the housing 122, respectively.

[0063] If the intravascular blood pump 100 may be in its expanded state and needs to be removed from the patient's body, the housing 122 can be retracted into the compression cannula 308, whereby the housing 122 is radially compressed and the housing 122 can extend longitudinally up to a length of 400. The filter 130 and the impeller 200 can also be compressed. By thus achieving a reduction in the diameter of the housing 122, it becomes easier to remove the intravascular blood pump 100 from the patient's body through the vasculature. Accordingly, the pump housing 122, the impeller 200, and the filter 130 are each configured to be alternately radially compressed and radially expanded. Further details of the expandable intravascular blood pump are described in U.S. Patent No. 8,439,859, the entire content of which is hereby incorporated by reference for all purposes.

[0064] FIG. 8 is a cross-sectional view of the expandable housing 122 and the expandable mesh filter 130 of FIGS. 6 and 7 in their expanded states. The housing 122 includes several members connected to each other. These members are, from proximal to distal, a proximal tubular housing member 500, a proximal tapered housing member 502, an intermediate tubular housing member 504, a distal tapered housing member 506, and a distal tubular housing member 508. As used herein, "tapered" means having a shape in which the outer diameter changes smoothly and monotonically, but not necessarily linearly. Thus, in profile, the tapered shape may include convex and / or concave portions. Tapered includes, but is not limited to, conical.

[0065] The proximal tubular housing member 500 can be attached to the catheter 106 and includes a proximal bearing 510. The proximal tubular housing member 500 has an essentially cylindrical shape. The proximal tapered housing member 502 connects the intermediate tubular housing member 504 to the proximal tubular housing member 500. The intermediate tubular housing member 504 has a generally cylindrical shape and surrounds the impeller 200. The exact cross-sectional shape of the intermediate tubular housing member 504 may depend on the number of struts 300-304 in the housing 122. Generally, the cross-sectional shape can be polygonal, with rounded corners in some cases.

[0066] The distal tapered housing member 506 connects the intermediate tubular housing member 504 to the distal tubular housing member 508 and defines the blood flow inlet (input port) 126 of the housing 122. The proximal tapered housing member 502 has a generally circular cross-section with a radius that increases in the distal direction. Similar to the intermediate tubular housing member 504, the exact cross-sectional shape of the proximal tapered housing member 502 may depend on the number of struts 300-304 and can generally be polygonal, with rounded corners in some cases.

[0067] Similarly, the distal tapered housing member 506 also has a generally circular cross-section, but its radius decreases in the distal direction. Similar to the intermediate tubular housing member 504, the exact cross-sectional shape of the distal tapered housing member 506 may depend on the number of struts 300-304 and can generally be polygonal, with rounded corners in some cases.

[0068] The distal tubular housing member 508 includes a distal bearing 512 and can be connected to the proximal section of the flexible atraumatic tip 120.

[0069] Expandable filter Attached to the outside of the extended housing 122 and thus shown in an extended state can be an expandable filter 130. The filter 130 can include a distal tubular filter section 514 having a relatively small diameter. The filter can include a proximal tubular filter section 516 having a larger diameter. Similar to the intermediate tubular housing member 504, the exact cross-sectional shape of the filter 130, including the exact cross-sectional shapes of the distal tubular filter section 514 and the proximal tubular filter section 516, can be determined by the number of struts 300-304 and / or the number of struts in the filter 130. Generally, the cross-sectional shape can be polygonal, optionally having rounded corners.

[0070] A tapered filter section 518 can connect the two tubular filter sections 516 and 514. The expandable filter 130 can cover the entire distal tapered housing member 506, i.e., the blood flow inlet (input port) 126, with its tapered filter section 518. The expandable filter can cover a part of the intermediate tubular housing member 504 with its proximal tubular filter section 516. In some embodiments, the expandable filter can cover a part, but not all, of the distal tubular housing member 508 with its distal tubular filter section 514. In some embodiments, the expandable filter can cover all of the distal tubular housing member 508 with its distal tubular filter section 514.

[0071] A distal outer foil 520 can be disposed over the distal tubular filter section 514. The distal tubular filter section 514 can be disposed over the distal tubular housing member 508. The distal outer foil 520 (or film) can prevent damage to the expandable filter 130. For example, the foil can prevent fraying if the expandable filter 130 is made of a strut mesh. If the distal tubular filter section 514 defines an aperture, the distal outer foil 520 can be directly attached through the aperture to a structure located below the distal tubular filter section 514, such as the flexible atraumatic tip 120. For example, the flexible atraumatic tip 120 and the distal outer foil 520 can be made of the same or a similar material, and the materials can be welded to each other through the aperture. Since the flexible atraumatic tip 120 can typically be made of polyether block amide (PEBA) or polyurethane, the distal outer foil 520 can also be made of PEBA or polyurethane, and the materials can be heat sealed together.

[0072] A proximal outer foil 522 can be disposed over the intermediate tubular housing member 504. The proximal tubular section 516 of the expandable filter 130 can be sandwiched between the proximal outer foil 522 and the intermediate tubular housing member 504, but only in the distal region of the proximal outer foil 522. The proximal outer foil 522 can prevent damage to the proximal tubular section 516 of the expandable filter 130. Additionally, the proximal outer foil 522 can be heat sealed to the inner sleeve or coating 310 of the housing 122 through the aperture of the expandable filter 130. The inner sleeve or coating 310 can be made of polyurethane (PU). When the inner sleeve or coating 310 is made of PU, the proximal outer foil 522 can also preferably be made of PU as well. When the filter 130 is made of a formed foil tube defining an aperture, the proximal outer foil 522 can be made integrally with the filter 130.

[0073] The distal end of the flexible outflow cannula 204 can be attached to the proximal section of the proximal outer foil 522. Alternatively, the flexible outflow cannula 204 may be made integrally with the proximal outer foil 522. When the filter 130 is made of a formed foil tube defining an aperture, the proximal outer foil 522 can be made integrally with the filter 130 and the flexible outflow cannula 204.

[0074] Helically woven filter FIG. 9 includes a perspective view of a distal section of an intravascular blood pump 100 having an intermediate tubular housing member 504, a distal tapered housing member 506, and a distal tubular housing member 508. In this embodiment, the expandable filter 130 can be a mesh made of filaments woven or connected to each other. Weaving is a manufacturing method in which two separate sets of filaments (warp and weft) are woven at an angle to form a fabric. The warp is composed of longitudinal filaments, and the weft (or filling) is composed of transverse filaments. The way the warp filaments and the weft filaments intersect with each other is called the weave pattern. Most fabric products are created in one of three basic weave patterns: plain weave, satin weave, or twill weave.

[0075] In plain weave, the warp filaments and the weft filaments intersect diagonally and are aligned to form a simple cross pattern. Each weft filament passes over a warp filament and then under the next warp filament, etc., intersecting the warp. The next weft filament passes under the warp that the adjacent weft passed over, and vice versa. The filaments of the fabric filter 130 are preferably in plain weave, but satin weave, twill weave, or other weave patterns may be used. Preferably, the mesh is not knitted and does not include loops.

[0076] Satin weave can be characterized by having four or more weft filaments floating over one warp filament and four or more warp filaments floating over one weft filament. Floating refers to a portion where there is no interaction, for example, where the warp filament is located over the weft filament in a vertical satin. Twill weave can be characterized by a pattern of diagonal parallel ribs. Twill weave can be created by putting a "step" or offset between rows that result in a characteristic diagonal pattern, passing a weft filament over one or more warp filaments and then under two or more warp filaments, etc.

[0077] Referring to FIG. 9, the filter 130 can be made of filaments represented by filaments 600, 602, 604, 608, 610, 612, 614, 616, and 618. Filaments 600 to 608 are generally helical first struts wound clockwise about the longitudinal axis 620 of the housing 122. As used herein, a "generally helical" curve is a generally smooth space curve. However, the pitch, radius, curvature, and twist, as used herein, may vary along the length of the helical curve. The helical curve is not essential, but can proceed helically around the axis by more than 360° or less than 360°. Further, a generally helical curve may include slight zigzags that are not necessarily all the same, as illustrated by generally helical curves 714 and 716 (FIG. 10).

[0078] Returning to FIG. 9, filaments 610 to 618 may be generally helical second struts wound counterclockwise about the longitudinal axis 620. Filaments 600 to 618 are shown by thick dashed lines for ease of viewing in the drawing. These filaments 600 to 618 are also reproduced in the inset of FIG. 9 for clarity. The first struts 600 to 608 and the second struts 610 to 618 together define a plurality of apertures represented by apertures 622, 624, and 626 therebetween. The first struts 600 to 608 and the second struts 610 to 618 are woven together such that a plurality of apertures 622 to 626 are defined between their respective adjacent first woven filaments 600 to 608 and second woven filaments 610 to 618.

[0079] Each aperture of at least a subset of the plurality of apertures 622-626 can have a generally rhombic, obliquely rhombic, or rectangular shape. As used herein, an obliquely rhombic shape refers to a parallelogram in which the lengths of adjacent sides are not equal and the angle between adjacent sides is non-right. As used herein, a rhombic shape refers to a parallelogram in which the lengths of adjacent sides are equal and the angle between adjacent sides is non-right. An obliquely rhombic, rhombic, and rectangular shape are not necessarily planar. An obliquely rhombic, rhombic, and rectangular shape may exist on a curved surface, as exemplified by the apertures 622-626. The sides of an obliquely rhombic, rhombic, or rectangular shape need not be perfectly straight, and the sides need not necessarily intersect at an angle, i.e., there may be a small radius at the location where two sides intersect with respect to the corners of the apertures defined by the shaped foil tube filter, as will be discussed in more detail later, for example.

[0080] In at least the middle portion 628 of the tapered filter section 518, the apertures 622-626 may preferably have a generally square shape. As the diameter of the filter 130 decreases, such as in the distal direction within the tapered filter section 518, the apertures 622-626 may gradually become smaller, and the apertures may assume an obliquely rhombic shape in which their major axes extend in the longitudinal direction. At the minimum diameter of the tapered filter section 518, the smaller interior angle of a rhombic or obliquely rhombic aperture may be less than about 75°.

[0081] As the diameter of the filter 130 increases, such as in the proximal direction within the tapered filter section 518, the apertures 622-626 may gradually become larger. At the maximum diameter of the tapered filter section 518, the larger interior angle of a rhombic or obliquely rhombic aperture may be greater than about 110°. The apertures may assume an obliquely rhombic shape in which their major axes extend in the circumferential direction. These numbers correspond to an embodiment in which the larger diameter of the filter 130 is about 2.5 times the smaller diameter of the filter 130. The angles can be adjusted for other ratios of the large diameter to the small diameter of the filter 130.

[0082] When the pump housing 122 is compressed radially, it can be configured to elongate longitudinally by an amount determined by the amount by which the pump housing 122 is compressed radially. The filter 130 can be configured to elongate longitudinally by an amount determined by the amount by which the filter 130 is compressed radially when compressed radially. The filter 130 can be configured such that for a given amount of radial compression, the filter 130 and the pump housing 122 elongate longitudinally by approximately equal amounts.

[0083] The filaments 600-618 can be made of a wire such as nitinol, a suitable polymer such as polyethylene terephthalate (PET) or PU, a fiber, or other suitable materials. The material of the filaments 600-618 is preferably a shape memory material. The individual filaments 600-618 can have a thickness of about 10 μm to about 80 μm, or about 20 μm to about 60 μm, for example about 40 μm. The catheter 106, the pump housing 122, the impeller 200, and the filter are configured for use in a living patient, and each of the plurality of apertures 622-626 is sized to prevent suction of the heart tissue of the living patient by the input port 126.

[0084] In some embodiments where the filter is formed of a mesh, the mesh can be ironed (pressed under heat) before attaching the filter 130 to the housing 122. Such ironing can melt the intersecting filaments 600-618, especially when the filaments 600-618 are made of a suitable heat-fusible plastic. Such melted filaments 600-618 form a stronger mesh.

[0085] In some embodiments, the woven fabric has a maximum distance between two adjacent filaments 600-618 of about 0.3 mm (300 μm) to about 0.4 mm (400 μm) when the filter 130 is in the expanded state. In some embodiments, each aperture of the plurality of apertures 622-626 has a maximum dimension of about 0.5 mm (500 μm) or less when the filter is in the expanded state. In some embodiments, each aperture of the plurality of apertures 622-626 has a maximum dimension of about 0.4 mm (400 μm) or less when the filter is in the expanded state. In some embodiments, each aperture of the plurality of apertures 622-626 has an area of about 0.09 mm 2 or less when the filter is in the expanded state.

[0086] As used herein, "maximum dimension" includes diagonal dimensions such as the dimension between two opposite corners on the diagonal of a quadrilateral. As used herein, the "diameter" of a convex shape means the maximum distance that can be formed between two opposite parallel lines that touch the boundary of the convex shape. As used herein, "width" means the minimum value of such a distance.

[0087] Molded foil tube filter FIG. 10 is a side view of an expandable filter 130 formed of a filter tube, and FIG. 11 is a view in its axial (longitudinal) direction. In some embodiments, the tube can generally be a funnel-shaped tube. FIG. 10 includes an inset showing an enlarged portion of the expandable filter 130. As described above, in some embodiments, the filter 130 includes a shaped foil tube 700 having apertures. The apertures can be openings that penetrate the walls forming the tube. The walls can be, for example, 10 to 100 μm thick. Examples of apertures are shown at 702, 704, and 706. The expandable filter 130 made from the shaped foil tube 700 can be compressed, i.e., made smaller in the radial direction, by folding some or all of the members of the filter 130. The filter 130 can be expanded from its compressed state by unfolding previously folded members. The compression and expansion depend mainly on this folding and unfolding, rather than elastic compression and elongation.

[0088] The apertures 702 - 706 can be positioned in the tube such that the materials 708, 710, and 712 between the apertures 702 - 706 form the first strut and the second strut as illustrated by the materials. In FIG. 10, two exemplary struts 714 and 716 are shown by thick dashed lines. As described above, generally helical curves may include slight zigzags, not necessarily all the same, as illustrated by the generally helical curves 714 and 716. These zigzags are more clearly seen, for example, in the struts 718 and 720 shown by thick solid and dashed lines in the inset of FIG. 10.

[0089] Although housing 122 is not shown in FIGS. 10 and 11, an enlarged filter 130 is shown as would be visible when attached to an enlarged housing 122 (e.g., FIG. 9). Filter 130 made of formed foil tube 700 can be made of a polymer such as PET or PU. The wall of foil tube 700 can be about 10 μm to about 100 μm thick, preferably about 15 μm to about 75 μm thick, more preferably about 20 μm to about 50 μm thick. The wall thickness of foil tube 700 may continuously decrease distally in tapered filter section 518, such as as a result of blow molding manufacture.

[0090] As shown in FIG. 12, foil tube 700 can be formed on mandrel 900. Mandrel 900 should have the desired shape of the completed filter 130 in the expanded state. Apertures 702 - 706 can then be defined in the formed tube by cutting or punching, etc. Apertures 702 - 706 can have a generally diamond or off - diamond or rectangular shape. The inner corners of apertures 702 - 706 of filter 130 based on foil tube 700 should have a radius of at least about 5 μm, preferably at least about 20 μm.

[0091] As contemplated herein, additional holes can be defined in the formed tube, such as to facilitate attachment of the formed tube to other components of intravascular blood pump 100. The formed - aperture tube can then be attached to housing 122 as shown in FIGS. 13 - 15 (housing 122 is not visible in FIG. 15). FIG. 13 is a cross - sectional view of the distal end region of expandable housing 122 with expandable filter 130 installed. FIG. 14 is a cross - sectional view similar to FIG. 13, but including an inner coating 310 of the expandable housing not shown in FIG. 13 for clarity. FIG. 15 is a perspective view of the distal end region of expandable housing 122 with the expandable filter of FIGS. 10 - 11 installed.

[0092] Returning to FIGS. 10 and 11, the shape and size of the holes may vary in different members of the expandable filter 130. In the distal tubular filter section 514, the holes exemplified by holes 722 may be longer (in the longitudinal direction) than wide (in the circumferential direction). The holes 722 can be defined in circumferential rows. The holes 722 in adjacent rows can be staggered in the circumferential direction and partially overlap in the longitudinal and circumferential directions, as shown in FIG. 10. Such staggering and overlap enable the distal tubular section 514 to expand easily during assembly without requiring elastic stretching of the material. This expansion can facilitate inserting the impeller 200 through the distal end of the housing 122 into the housing 122. Further, such staggering generally allows the holes 722 to be placed closer to each other, thus improving the permeability of the filter 130 to blood flow.

[0093] The distal outer foil 520 (FIG. 13) can be heat-sealed, such as by welding, through the holes 722 of the distal tubular filter section 514 that extends to the proximal section of the flexible atraumatic tip 120. Each hole 722 of the distal tubular filter section 514 has an enlarged portion located at the center of the longitudinal slot. After the impeller 200 is inserted and the distal tubular portion 514 returns to its normal diameter, the enlarged portion advantageously has a relatively large open contact area for attaching the distal outer foil 520 to the flexible atraumatic tip 120.

[0094] The expandable filter 130 further includes a transition zone 724 (FIG. 10) where the distal tubular filter section 514 and the tapered filter section 518 intersect. The holes exemplified by the holes 726 in the transition zone 724 are longer and wider than the adjacent holes in the tapered filter section 518. Preferably, the holes 726 in the transition zone 724 are at least twice as large as the adjacent holes exemplified by the holes 728 in the tapered filter section 518. In one embodiment, for each pair of circumferentially adjacent holes 728 in the rows of the tapered filter section 518, the transition zone 724 has one hole 726 that spans the two holes 728 in the circumferential direction. Thus, the number of holes in the circumferential rows in the transition zone 724 may be half the number of holes in the circumferential rows in the tapered filter section 518. In some other embodiments, other ratios such as 3:1, 4:1, or 3:2 may be used. Each hole 726 in the transition zone 724 may be about twice, three times, or another multiple of the length (in the longitudinal direction) of the holes 728 in the tapered filter section 518, and about twice, three times, or another multiple of the width (in the circumferential direction), depending on the ratio of the number of holes 728 in one row of the tapered filter section 518 to the number of holes 726 in one row of the holes 726 in the transition zone 724.

[0095] The dimensions and shapes of the holes 702 - 706 and 728, and the dimensions of the struts 714 - 716 should be selected such that the housing 122 can be inserted into the tapered filter section 518 without exceeding the limits of elastic deformation of the material when the tapered filter section 518 is fully open. For example, considering any local elastic deformation of the filter material, the product of the length of two circumferentially adjacent struts 714 - 716 (on the zigzag of the zigzag circumferential ring) and the number of apertures 702 - 706 in the circumferential row should be approximately equal to the circumference of the fully expanded housing 122.

[0096] Adjacent holes 726 in the transition zone 724 are separated from each other by struts that are wider than the adjacent struts 714-716 of the tapered filter section 518. These wider struts stabilize the larger holes 726. When the distal outer foil 520 is disposed longitudinally proximal to the distal tubular filter section 514 up to the transition zone 724, the distal outer foil 520 at least partially covers the first one or more rows of holes 726 in the transition zone 724, thus reducing their effective size. In some cases, this reduction in the size of these holes can lead to an increased risk of blood damage or blood clotting. Therefore, the holes 726 in the transition zone 724 should be selected to be larger than the holes in the tapered filter section 518.

[0097] As can be seen in FIG. 10, the holes 728 in the distal region of the tapered filter section 518 are narrower in the circumferential direction than the holes 702-706 in the proximal region of the tapered filter section 518. In other words, the size of the apertures 702-706 increases monotonically in the proximal direction along the longitudinal axis. Additionally, in the distal tubular filter section 514, the holes 722 take the form of narrow axially offset slits in the circumferential direction. This is advantageous because the narrow holes can expand when the expandable filter 130 expands in the distal tubular filter section 514 and the distal region of the tapered filter section 518, such as when the impeller 200 is inserted into the housing 122. The wider holes are bounded by thicker struts, particularly in the tapered filter section 518. The struts have a width ranging from approximately 30 μm in the distal region of the tapered filter section 518 to approximately 60 μm in the proximal region. Preferably, the maximum diameter of the holes in the tapered filter section 518 is from about 300 μm to about 500 μm.

[0098] In the embodiment shown in FIG. 10, the proximal tubular filter section 516 has no holes. However, when the proximal outer foil 522 is disposed over the proximal tubular filter section 516 (FIG. 8) and can be further positioned over the intermediate tubular housing member 504, holes in the proximal tubular filter section 516 may be desirable. The proximal outer foil 522 can fix the expandable filter 130 to the housing 122 and coat the tubular housing member 504 with PU, and since the proximal outer foil 522 can also be made of PU, they can be easily heat-sealed or welded to each other through such holes. However, when both the filter 130 and the proximal outer foil 522 are made of a compatible material such as PU, the filter 130 and the proximal outer foil 522 can be joined directly to each other by applying heat or the like.

[0099] When the expandable filter 130 of FIGS. 10 and 11 is disposed on the expanded housing 122 as shown, for example, in FIG. 13, the distal tubular filter section 514 can preferably be disposed over the distal bearing 512 and the flexible atraumatic tip 120. To fasten the expandable filter 130 to the intravascular blood pump 100, the distal tubular filter section 514 can be covered with a distal outer foil 520.

[0100] The proximal tubular filter section 516 has a relatively large diameter. If this diameter cannot change significantly during the assembly of the intravascular blood pump 100, i.e., if the proximal opening of the filter 130 cannot be significantly stretched, any holes defined in this section will not deform significantly during assembly. Thus, these holes can be square or another shape, and the holes can be at least partially defined by a circumferential ring of struts. FIG. 16 shows such an embodiment. FIG. 16 is a side view of the expandable filter 130 of FIGS. 10 and 11 according to an alternative embodiment of the present invention.

[0101] The expandable filter 130 of FIG. 16 includes a band 1300 of several parallel rings of holes, exemplified by holes 1302, 1304, and 1306 and rings 1308 and 1310. All of the rings 1308 - 1310 have the same number of holes 1302 - 1306, and the holes 1302 - 1306 are mainly of equal size. As a result, the ratio of the total pore area to the total strut area within the band 1300 can be relatively high compared to other parts of the filter 130. A high pore - to - strut ratio can be advantageous as it improves the permeability of the filter 130 to blood flow and reduces the risk of hemolysis and coagulation. The ratio of the total pore area to the total area of the filter 130 exposed to blood should be at least about 60%, preferably at least about 70%, more preferably at least about 80%. This band 1300 can be combined with the large holes 726 in the transition zone 724 discussed herein with respect to FIG. 10.

[0102] The description of the shape of the holes and apertures pertains to the expanded filter 130. When the filter is compressed, e.g., by folding, the shape of the holes can change drastically. In fact, what makes the filter 130 easy to compress is the ability of the struts to bend.

[0103] FIG. 17 is a perspective view of the distal end region of the expandable housing of FIGS. 13 and 14, similar to that of FIGS. 10 and 11 and / or FIG. 16, but with an expandable filter having a different aperture pattern installed. For example, some of the struts are fork - shaped, as exemplified by strut 1400. Some of the struts, such as the fork - shaped strut 1400, may be wider than other struts. Some of the struts exemplified by struts 1402 and 1404 extend between each pair of the teeth of the fork. Thus, a plurality of first struts and a plurality of second struts extend between a pair of teeth and together define a plurality of apertures therebetween. Each first strut including a fork may be wider than each second strut not including a fork.

[0104] Optionally, one or more of the struts may be aligned on respective struts of the housing 122. As shown in FIG. 13, the housing 122 includes struts represented by struts 300 as discussed with respect to FIGS. 6 and 7. The struts 300 of the housing are referred to herein as third struts. The group of these third struts represented by struts 1000 (FIG. 13) collectively define an aperture represented by aperture 1002 (FIG. 13) that passes therethrough. At least some of the first and second struts, i.e., the struts in the filter (see FIG. 10) such as the forked struts 1400 (FIG. 17), are radially aligned on respective ones of the third struts for support.

[0105] FIG. 18 is a perspective view of the distal end region of the expandable housing of FIGS. 13 and 14 with an expandable filter similar to that of FIG. 17 attached, but having a different aperture pattern, according to another alternative embodiment of the present invention.

[0106] FIG. 19 is a side view of the distal end region of the expandable housing of FIGS. 13 and 14 with an expandable filter similar to that of FIG. 17 attached, according to yet another alternative embodiment of the present invention.

[0107] FIG. 20 is a side view of the distal end region of the expandable housing of FIGS. 13 and 14 with a long inflow cannula 1701 and a bulbous expandable filter 1700 having an enlarged inflow region 1702 installed therein. FIG. 21 is a side view of the distal end region of the expandable housing of FIGS. 13 and 14 without a long inflow cannula, but with an outflow cannula and a bulbous expandable filter 1800 having an enlarged inflow region 1802 installed therein, which is otherwise similar to FIG. 20.

[0108] The bulbous expandable filters 1700 and 1800 provide enlarged inflow regions 1702 and 1802 to the intravascular blood pump 100, thereby improving the flow characteristics of the pump. The enlarged inflow regions 1702 and 1802 are similar to those in FIGS. 13-15 but are covered by a filter 1704 having a larger aperture.

[0109] The filter 130 includes a distal portion 1706 and a proximal portion 1708. The distal portion 1706 monotonically increases in diameter in the proximal direction along the longitudinal axis. The proximal portion 1708 monotonically decreases in diameter in the proximal direction along the longitudinal axis.

[0110] At least a portion of the plurality of apertures 702-706 can be disposed on the distal portion 1706. In some embodiments, there may be no apertures in the proximal portion 1708.

[0111] Generally, the size of the apertures among the plurality of apertures 702-706 increases in the distal direction along the longitudinal axis, but this increase does not necessarily have to be monotonic. The apertures 702-706 are arranged in a plurality of generally circumferential rows of apertures of equal size, exemplified by rows 1710, 1712, and 1714. Some of the rows 1710-1714 have a different number of apertures 702-706 than other rows among the rows 1710-1714. For example, the first row 1710 (shown by the dashed line) among the plurality of generally circumferential rows includes more apertures 702 than the second row 1712 among the plurality of generally circumferential rows. Each aperture 702 in the first row 1710 has a smaller area than each aperture 704 in the second row 1712.

[0112] The apertures 702-706 can be arranged in a plurality of bands of apertures of generally equal size that are generally circumferential with respect to the longitudinal axis, as illustrated by bands 1716, 1718, and 1720. The size of the apertures 702-706 in each of the plurality of bands 1718-1722 increases monotonically along the longitudinal axis. That is, generally, the apertures in band 1720 are larger than the apertures in band 1718. However, the apertures in a given column may be larger or smaller than the apertures in another column in the same band, although the two columns have the same number of apertures but may have different circumferences. In the embodiment shown in FIG. 20, the size of the apertures 702-706 in each of the plurality of bands 1718-1722 increases monotonically along the longitudinal axis in the distal direction. Other aspects of the size and arrangement of the apertures are the same as those considered with respect to FIG. 10.

[0113] As described above, the distal end region of the expandable housing shown in FIG. 21 is similar to that of FIG. 20, except that the expandable housing of FIG. 21 includes a flexible outflow cannula and does not include a relatively long inflow cannula. For example, in some embodiments, the distance between the blood inlet and the impeller may be less than half the length of the outflow cannula. In some embodiments, the distance between the blood inlet and the impeller may be less than 10% of the length of the outflow cannula.

[0114] FIG. 22 is a perspective view of the distal end region of the expandable housing of FIGS. 13 and 14, similar to that of FIG. 17, but comprising an expandable filter having a number of longitudinal struts illustrated by longitudinal strut 1900. Each longitudinal strut 1900 is located in a respective plane illustrated by plane 1902, which includes the longitudinal axis 620. As used herein, the phrase "plane including" a line means that the line is completely located within that plane. FIG. 22 shows only one longitudinal strut 1900, but the filter 130 may include additional longitudinal struts (not shown).

[0115] In some embodiments, the blood pump can have an elastically radially compressible ("crimpable") pump housing and optionally a radially compressible impeller to facilitate insertion of the pump into the patient's body. While the blood pump and the impeller are in a compressed state, the blood pump having the compressible housing can be inserted into the patient's body, and then, after the blood pump is properly positioned, the pump housing and the impeller can be expanded radially.

[0116] FIG. 23 is a graphical illustration of an example of such a process. FIG. 23 provides a side view of the blood pump 2300 at six stages ((1)-(6)) emerging from the tubular sheath 2310 as the tubular sheath 2310 is withdrawn from the blood pump 2300, as indicated by the arrow 2312. As the tubular sheath 2310 can be withdrawn, a portion of the blood pump 2300, particularly the mesh structure 2302 and the impeller 2304, elastically expands radially, and the pigtail 2306 becomes helical.

[0117] FIG. 24 is a flowchart schematically showing a method 2400 of crimping a blood pump. The method 2400 can be implemented using a crimping tool, for example, as is well known in the art. The method includes placing the blood pump inside the distal end of a tapered longitudinal tube bore (2402). The tube bore can be defined by a long tube. The tube bore can be at least about 30 mm in length. The tube bore can have an inner dimension that tapers along the length of the tube bore from (a) at least approximately the maximum outer diameter dimension of the pump at the distal end of the tube bore to (b) at most a diameter of about 4 mm at the proximal end of the tube bore.

[0118] At 2404, the blood pump is translated in a direction through the tube bore towards the proximal end of the tube bore, which includes contacting the outer surface of the blood pump with the inner surface of the elongate tube as the blood pump is translated through the tube bore, thereby being able to crimp the blood pump and result in a crimped blood pump.

[0119] In some embodiments, translating the blood pump can include pulling the blood pump through the tube bore. However, in principle, translating the blood pump may include pushing the blood pump through the tube bore.

[0120] In some embodiments, the inner dimension of the distal end of the tube bore may be at least about 7 mm. In some embodiments, the inner dimension of the proximal end of the tube bore may be at most about 4 mm. In some embodiments, the inner dimension of the distal end of the tube bore may be at least about 7 mm and the inner dimension of the proximal end of the tube bore may be at most about 4 mm. In some embodiments, the tube bore may be at least about 50 mm in length. In some embodiments, the tube bore may be at least about 100 mm in length. In some embodiments, the tube bore may be at least about 170 mm in length. In some embodiments, the tube bore may be at least about 300 mm in length.

[0121] Optionally, the inner wall of the tube defining the tapered tube bore may extend at an angle of less than about 2° with respect to the longitudinal axis of the tube. Optionally, the taper ratio of the tapered tube bore, calculated as the ratio of (a) the change in the inner diameter of the tube bore to (b) the length of the taper along the longitudinal axis of the tube, may be about 1:14 or less.

[0122] Optionally, at 2406, the tubular sheath can be disposed substantially coaxially with the proximal end of the tube bore.

[0123] Optionally, at 2408, the crimped blood pump can be translated from the proximal end of the tube bore to the tubular sheath without substantially changing the outer dimensions of the crimped blood pump. Translating the crimped blood pump from the proximal end of the tube bore to the tubular sheath (2408) can include (a) releasably restraining the distal end portion of the tubular sheath within the hub (2410). The hub is attached to the proximal end of the tube. The hub defines a hub bore that is coaxial with the tube bore and passes through the hub. One end of the hub bore is connected to the proximal end of the tube bore. The other end of the hub bore is configured to receive the distal end portion of the tubular sheath substantially coaxially with the tube bore. Translating the crimped blood pump from the proximal end of the tube bore to the tubular sheath (2408) can also include (b) translating the crimped blood pump through the hub bore (2412). Optionally, the method further includes releasing the distal end portion of the tubular sheath from the hub (2414).

[0124] Optionally, the method includes translating the crimped blood pump from the tubular sheath into the patient's vasculature (2416) and allowing the crimped blood pump to elastically expand within the vasculature (2418).

[0125] FIG. 25 is a flowchart generally showing another method 2500 of clamping a blood pump. The method 2500 can be implemented using a frangible clamping tool, for example, as known in the art. The method 2500 includes disposing the blood pump inside the distal end of a tapered longitudinal tube bore (2502). The tube bore can be defined by a long tube. The proximal end of the tube can be coaxially and frangibly attached to the distal end of a tubular sheath. The tubular sheath can have an inner dimension (e.g., inner diameter). The tube bore can be at least about 30 mm in length. The tube bore can have an inner diameter dimension that tapers along the length of the tube bore from (a) at least approximately the maximum outer diameter dimension of the blood pump at the distal end of the tube bore to (b) approximately the inner dimension of the tubular sheath at the proximal end of the tube bore.

[0126] At 2504, the blood pump can be translated through the tube bore in a direction toward the proximal end of the tube bore, which includes contacting the outer surface of the blood pump with the inner surface of the long tube as the blood pump is translated through the tube bore, thereby clamping the blood pump to result in a clamped blood pump. At 2506, the clamped blood pump can be translated from the proximal end of the tube bore to the tubular sheath without substantially changing the outer diameter dimension of the clamped blood pump. At 2508, with the clamped blood pump disposed within the tubular sheath, the tubular sheath can be frangibly separated from the tube.

[0127] The present invention has been described through the above-exemplified embodiments. However, changes and modifications to the exemplified embodiments can be made without departing from the concept of the invention disclosed herein. For example, in relation to the disclosed embodiments, specific parameter values such as dimensions and materials may be listed, but within the scope of the present invention, the values of all parameters can be changed over a wide range to suit different applications. Unless otherwise indicated in the context or otherwise understood by those skilled in the art, terms such as "about" mean within ±20%.

[0128] As used herein, including in the claims, the term "and / or" when used in connection with a list of items means one or more of the items in the list, i.e., at least one of the items in the list, but not necessarily all of the items in the list. As used herein, including in the claims, the term "or" when used in connection with a list of items means one or more of the items in the list, i.e., at least one of the items in the list, but not necessarily all of the items in the list. "Or" does not mean "exclusive or".

[0129] The disclosed aspects or parts thereof may be combined in ways not listed above and / or not explicitly claimed. In addition, the embodiments disclosed herein can be suitably implemented even without any element not specifically disclosed herein. Therefore, the present invention should not be regarded as limited to the disclosed embodiments.

[0130] As used herein, terms related to numerical values such as "first", "second", and "third" are used to distinguish the respective struts, rings of the aperture, and / or bands of the aperture from each other, and are not intended to indicate any particular order or total number of struts, rings of the aperture, and / or bands of the aperture in any particular embodiment. Thus, for example, a given embodiment may include only a second strut, ring of the aperture, and / or band of the aperture and a third strut, ring of the aperture, and / or band of the aperture.

Claims

1. A pump housing having a blood flow inlet, A catheter operably connected to the proximal end of the pump housing, the catheter having an outer diameter smaller than the outer diameter of the pump housing, A flexible outflow cannula having a proximal end portion operably connected to the catheter, a plurality of blood flow outlets, and a distal end portion operably connected to the pump housing, wherein the pump housing and the flexible outflow cannula define a blood flow path from the blood flow inlet of the pump housing to the plurality of blood flow outlets, An impeller, disposed within the pump housing and configured to rotate around a rotation axis for transporting blood from the blood inlet to the plurality of blood outlets, Equipped with, The proximal end portion of the flexible outflow cannula has a connecting portion connected to the catheter and an unconnected portion extending distally from the connecting portion. At least one slit is formed through all of the connecting portions and extends to the proximal end of the flexible outflow cannula, The plurality of blood flow outlets include one or more resection outlets, A blood pump in which each slit is connected to the proximal end of one of the one or more excision outlets, and one of the one or more excision outlets is connected to each slit, and each slit has a tapered proximal end and extends distally from the unconnected portion.

2. The blood pump according to claim 1, wherein at least one slit extends distally from the connecting portion through at least a portion of the unconnected portion before connecting to the cutting outlet.

3. The blood pump according to claim 1, wherein the plurality of blood outlets consist of four blood outlets, and the four blood outlets each have exactly one cut-out outlet or exactly two cut-out outlets.

4. The blood pump according to claim 3, wherein the flexible outflow cannula includes an intermediate portion extending between the distal end portion and the proximal end portion, and the intermediate portion has an outer diameter larger than the outer diameter of the pump housing.

5. The blood pump according to claim 4, wherein each of the plurality of blood flow outlets is at least partially located in the intermediate portion, and only one or more of the cutout outlets is at least partially located in both the proximal end portion and the intermediate portion.

6. The blood pump according to claim 1, wherein each of the one or more cutouts includes a distal portion, a proximal portion, and an intermediate portion between the distal portion and the proximal portion, the intermediate portion having substantially parallel sides.

7. The blood pump according to claim 1, further comprising (a) a filter that is in fluid communication with the internal volume of a blood vessel into which the blood pump is inserted, located outside the pump housing, and (b) the blood inlet, wherein the filter comprises a plurality of generally helical first struts and a plurality of second struts wound around a longitudinal axis, and the plurality of generally helical first struts and the plurality of second struts together define a plurality of apertures between them.

8. The blood pump according to claim 7, wherein the pump housing, the impeller, and the filter are each alternately radially compressible and radially expandable.

9. The blood pump according to claim 8, wherein the pump housing is configured to expand longitudinally by an amount determined by the amount of radial compression of the pump housing when compressed radially, and the filter is configured to expand longitudinally by an amount determined by the amount of radial compression of the filter when compressed radially, so that the filter and the pump housing expand longitudinally by approximately equal amounts with respect to a given amount of radial compression.

10. The blood pump according to claim 8, wherein the filter includes a tube having a wall, and the plurality of apertures include a plurality of openings defined through the wall.

11. The blood pump according to claim 10, wherein the tube generally includes a funnel-shaped tube.

12. The blood pump according to claim 10, wherein the pump housing comprises a plurality of third struts, the plurality of third struts collectively defining a plurality of third apertures between them, and at least some of the plurality of generally helical first struts and the plurality of second struts are radially aligned on each of the plurality of third struts.

13. The blood pump according to claim 10, wherein each strut of at least a subset of the plurality of generally helical first struts includes a fork having a plurality of teeth, and two or more of the plurality of generally helical first struts and two or more of the plurality of second struts extend between pairs of teeth and together define a plurality of apertures between them.

14. The blood pump according to claim 13, wherein each first strut including the fork is wider than each first strut not including the fork.

15. The blood pump according to claim 10, wherein the plurality of apertures are arranged in a plurality of rows of apertures of equal size, generally circumferential with respect to the longitudinal axis, and some of the rows have a different number of apertures than the other rows.

16. The blood pump according to claim 15, wherein the first of the plurality of generally circumferential rows includes more apertures than the second of the plurality of generally circumferential rows, and each aperture of the first row has a smaller area than each aperture of the second row.

17. The blood pump according to claim 10, wherein the plurality of apertures are arranged in a plurality of bands of approximately equal size that are generally circumferential with respect to the longitudinal axis, and the size of the aperture in each of the plurality of bands increases monotonically along the longitudinal axis.

18. The blood pump according to claim 17, wherein the filter includes a distal portion and a proximal portion, the distal portion having a diameter that increases monotonically in the proximal direction along the longitudinal axis, the proximal portion having a diameter that decreases monotonically in the proximal direction along the longitudinal axis, and at least a portion of the plurality of apertures is located in the distal portion.

19. The blood pump according to claim 7, wherein the plurality of generally helical first struts and the plurality of second struts are not accompanied by any circumferential struts with respect to the longitudinal axis.

20. A pump housing having a blood flow inlet, A catheter operably connected to the proximal end of the pump housing, the catheter having an outer diameter smaller than the outer diameter of the pump housing, A flexible outflow cannula having a proximal end portion operably connected to the catheter, a plurality of blood flow outlets, and a distal end portion operably connected to the pump housing, wherein the pump housing and the flexible outflow cannula define a blood flow path from the blood flow inlet of the pump housing to the plurality of blood flow outlets, An impeller, disposed within the pump housing and configured to rotate around a rotation axis for transporting blood from the blood inlet to the plurality of blood outlets, Equipped with, The proximal end portion of the flexible outflow cannula has a connecting portion connected to the catheter and an unconnected portion extending distally from the connecting portion. At least one slit is formed through all of the connecting portions and extends to the proximal end of the flexible outflow cannula, The plurality of blood flow outlets include one or more resection outlets, A blood pump in which each slit is connected to the proximal end of one of the one or more excision outlets, and one of the one or more excision outlets is connected to each slit, and each slit has a tapered proximal end and extends distally from the unconnected portion, A blood pump wherein either (i) the at least one slit is configured to allow at least a first portion of the connecting portion of the proximal end portion to overlap with a second portion of the connecting portion of the proximal end portion, or (ii) the at least one slit is configured to prevent the first portion of the connecting portion of the proximal end portion from overlapping with a second portion of the connecting portion of the proximal end portion.

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