Flexible outflow cannula with shaped outlet

Abstract

A blood pump is provided that may include a pump housing and a catheter operably coupled to the pump housing. The pump may 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 may have a coupled portion coupled to the catheter and an uncoupled portion extending distally from the coupled portion, wherein at least one slit may be formed throughout the coupled portion. The slit may extend distally from the coupled portion through at least a portion of the uncoupled portion and connect to a proximal end of at least one blood flow outlet ("incision outlet") having a tapered proximal end and extending distally from the uncoupled portion.

Description

[0001] Cross - reference to related applications

[0002] 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. Technical field

[0003] The present disclosure relates to a blood pump outflow cannula having a shaped (such as V - shaped) outlet. Background art

[0004] Blood pumps that can use outflow cannulas are used to ensure the movement of blood from one area of the human body to an adjacent area around an obstruction, valve, etc. For example, a blood pump can be used to move blood from the left ventricle past the aortic valve.

[0005] However, as the size of the blood pump decreases, two challenges arise: being able to manufacture smaller and smaller devices while still ensuring that the device does not promote thrombus formation. Summary of the invention

[0006] In various aspects, a blood pump can be provided. The blood pump can include a pump housing having a blood flow inlet, a catheter operatively coupled to the proximal end of the pump housing, a flexible outflow cannula, and an impeller. The flexible outflow cannula can have a proximal portion operatively coupled to the catheter, a plurality of blood flow outlets, and a distal portion operatively coupled 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. The impeller can be disposed within the pump housing and configured to rotate about a rotation axis for transporting blood from the blood flow inlet to the plurality of blood flow outlets.

[0007] 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 coupling portion coupled to the catheter and an uncoupled portion extending distally from the coupling portion. At least one slit can be formed through the entire coupling portion and extend to the proximal end of the flexible outflow cannula. The plurality of blood flow outlets can include at least one incised outlet, and the slit can extend distally from the coupling portion through at least a portion of the uncoupled portion and connect to the proximal end of at least one of the incised outlets. The incised outlet can have a tapered proximal end and extend distally from the uncoupled portion.

[0008] 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 incised outlet or exactly two incised outlets. In some embodiments, each of the plurality of blood flow outlets can be circumferentially equidistantly spaced from an adjacent blood flow outlet. In some embodiments, the incised outlet consists of one blood flow outlet.

[0009] In some embodiments, the flexible outflow cannula may include an intermediate portion extending between a distal portion and a proximal portion, and an outer diameter of the intermediate portion may be greater than an outer diameter of the pump housing.

[0010] In some embodiments, each of the plurality of blood flow outlets may be at least partially positioned within the intermediate portion, and only the incision outlet is at least partially positioned within both the proximal portion and the intermediate portion.

[0011] In some embodiments, the flexible outflow cannula may be defined by a substantially tubular member having a sidewall thickness of less than 20 microns.

[0012] In some embodiments, each incision outlet may include 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. In some embodiments, the proximal portion of the incision outlet forms an incision having straight non-parallel sides. In some embodiments, the proximal portion of the incision outlet forms an incision having concave sides. In some embodiments, the proximal portion of the incision outlet forms an incision having convex sides. In some embodiments, a width of a proximal end of the proximal portion may be equal to a width of the slit cross-connection portion. In some embodiments, a width of a proximal end of the proximal portion may be greater than a width of the slit cross-connection portion.

[0013] In some embodiments, the slit may be configured to allow at least a first portion of a connection portion of the proximal portion to overlap a second portion of the connection portion of the proximal portion. In some embodiments, the slit may be configured to prevent a first portion of a connection portion of the proximal portion from overlapping a second portion of the connection portion of the proximal portion.

[0014] In some embodiments, the blood pump may include a filter that is in fluid communication between (a) an internal volume of a blood vessel into which the blood pump outside the pump housing may be inserted and (b) the blood flow inlet, the filter including a plurality of generally helical first struts wound around the longitudinal axis and including a plurality of second struts, the first struts and the second struts together defining a plurality of orifices therebetween.

[0015] In some embodiments, the pump housing, the impeller, and any filter may each be alternately radially compressible and radially expandable.

[0016] In some embodiments, the pump housing may be configured to longitudinally lengthen by an amount that depends on the amount by which the pump housing may be radially compressed when radially compressed, and the filter may be configured to longitudinally lengthen by an amount that depends on the amount by which the filter may be radially compressed when radially compressed, such that for a given amount of radial compression, the filter and the pump housing longitudinally lengthen by approximately equal amounts.

[0017] In some embodiments, the catheter, pump housing, impeller, and filter may be configured for use with a living patient such that the size of each of the plurality of apertures can be designed to prevent the intake of cardiac tissue of the living patient into the blood flow inlet.

[0018] In some embodiments, each of the plurality of apertures may have a maximum size less than or equal to about 0.5 mm. In some embodiments, each of the plurality of apertures may have a maximum size less than or equal to about 0.4 mm. In some embodiments, each of the plurality of apertures may have an area less than or equal to about 0.09 mm 2 In some embodiments, each of the plurality of apertures may have an area less than or equal to about 0.16 mm 2 In some embodiments, the plurality of apertures may have dimensions that increase monotonically along the longitudinal axis.

[0019] In some embodiments, the generally helical first struts may be wound clockwise about the longitudinal axis, and the second struts may be wound generally helically about the longitudinal axis counterclockwise. In some embodiments, the generally helical first struts may be wound about the longitudinal axis in a first direction, and the second struts may be wound generally helically about the longitudinal axis in the first direction. In some embodiments, each strut of at least one subgroup of the second struts may be located in a respective plane that contains the longitudinal axis. In some embodiments, each aperture of at least one subset of the plurality of apertures may have a generally rhomboidal or rhomboid shape. In some embodiments, the generally helical first struts may include a plurality of first filaments, the second struts may include a plurality of second filaments, and the first filaments and the second filaments may be woven together such that the plurality of apertures may be defined between respective adjacent first woven filaments and second woven filaments. In some embodiments, the filter may include a tube having a wall, wherein the plurality of apertures may include a plurality of openings defined through the wall. In some embodiments, the tube may include a generally funnel-shaped tube. In some embodiments, the wall may be about 10 - 100 μm thick.

[0020] In some embodiments, the pump housing may include a plurality of third struts that together define a plurality of third apertures therebetween, and at least some of the first struts and the second struts are radially aligned with respective third struts among the third struts.

[0021] In some embodiments, each strut of at least one subset of the first struts may include a forked portion that includes a plurality of tines, wherein the plurality of first struts and the plurality of second struts may extend between a pair of tines and may together define a plurality of apertures therebetween. In some embodiments, each first strut that includes a forked portion may be wider than each first strut that does not include a forked portion.

[0022] In some embodiments, a plurality of orifices may be arranged in a plurality of circumferentially disposed rows of orifices of substantially equal size relative to a longitudinal axis, where one or more of the rows has a different number of orifices than the other rows.

[0023] In some embodiments, a first row of a plurality of substantially circumferential rows may include more orifices than a second row of the plurality of substantially circumferential rows, and each orifice of the first row may have a smaller area than each orifice of the second row.

[0024] In some embodiments, orifices may be arranged in a plurality of circumferentially disposed bands of orifices of approximately equal size relative to a longitudinal axis, where the size of the orifices in each of the plurality of bands increases monotonically along the longitudinal axis.

[0025] In some embodiments, a filter may include a distal portion and a proximal portion, the diameter of the distal portion may increase monotonically in the proximal direction along the longitudinal axis, the diameter of the proximal portion may decrease monotonically in the proximal direction along the longitudinal axis, and at least a portion of the plurality of orifices may be provided on the distal portion.

[0026] In some embodiments, a first strut and a second strut that are substantially helical may have no circumferential struts relative to the longitudinal axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings incorporated in and forming 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.

[0028] Figure 1 is a perspective view illustration of a blood pump.

[0029] Figure 2 is a top view illustration of a flexible outflow cannula.

[0030] Figures 3A - 3E is a top view illustration of an incisional outlet.

[0031] Figure 4A and 4B is an end view illustration of a flexible outflow cannula.

[0032] Figure 5 is a partial cross-sectional view of a blood pump positioned within the left ventricle of the heart.

[0033] Figures 6 - 7 are respectively Figure 1 and Figure 5 the expandable housing of an intravascular blood pump and in the expanded state ( Figure 6 ) and the compressed state ( Figure 7Enlarged side cross-sectional view of the expandable mesh filter.

[0034] Figure 8 is a cross-sectional view of the expandable housing and the expandable mesh filter in an expanded state according to an embodiment of the present invention. Figure 6 of the expandable housing and the expandable mesh filter.

[0035] Figure 9 Shows a perspective view of an expandable filter formed of a long wire mesh and mounted on the distal region of an expandable housing of an intravascular blood pump according to an embodiment of the present invention. Figures 1 - 5 of the intravascular blood pump ( Figures 6 - 8 ).

[0036] Figure 10 is a side view of an expandable filter formed of a filter tube according to another embodiment of the present invention.

[0037] Figure 11 is an axial (longitudinal) view of an expandable filter formed of a filter tube according to another embodiment of the present invention.

[0038] Figure 12 is a side view illustration of a method for forming a filter tube according to an embodiment of the present invention for Figure 10 and Figure 11 .

[0039] Figure 13 is a cross-sectional view of the distal region of an expandable housing according to an embodiment of the present invention, on which is mounted an expandable filter for Figures 6 - 8 and Figure 10 and Figure 11 .

[0040] Figure 14 is a cross-sectional view as in Figure 13 , however, including an inner coating of the expandable housing, which is not shown in Figure 13 for clarity.

[0041] Figure 15 is Figures 13 - 14 a perspective view of the distal region of an expandable housing, on which is mounted an expandable filter for Figures 10 - 12 .

[0042] Figure 16 is Figures 10 - 11 a side view of an expandable filter.

[0043] Figure 17 is Figures 13 - 14 a perspective view of the distal region of an expandable housing, on which is mounted an expandable filter similar to Figures 10 - 11 and / or Figure 16 , but having a different orifice pattern.

[0044] Figure 18 is Figures 13 - 14 a perspective view of the distal region of an inflatable housing of Figure 17 on which is mounted an inflatable filter similar to Figure 17 but having a different orifice pattern from that of

[0045] Figure 19 is Figures 13 - 14 a side view of the distal region of an inflatable housing of Figure 17 on which is mounted an inflatable filter similar to

[0046] Figure 20 is Figures 13 - 14 a side view of the distal region of an inflatable housing of

[0047] Figure 21 is Figures 13 - 14 a side view of the distal region of an inflatable housing of

[0048] Figure 22 shows a perspective view of an inflatable filter formed of a long wire mesh and mounted on the distal region of an inflatable housing ([[]] Figures 6 - 8 [[]]) of an intravascular blood pump of Figure 1 and Figure 5 similar to Figure 9 but having some longitudinal struts.

[0049] Figure 23

[0050] is a diagram showing the stages of inflating a blood pump according to one embodiment.

[0050] Figures 24 - 25 is a flow chart of an embodiment of a method for crimping a blood pump.

[0051] It should be understood that the drawings are not necessarily to scale and represent a somewhat simplified representation of various features illustrating the basic principles of the invention. Specific design features of the operating sequences disclosed herein, including, for example, the specific dimensions, orientations, positions, and shapes of the various illustrated components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been exaggerated or distorted relative to other features for purposes of visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. DETAILED DESCRIPTION

[0052] The following description and drawings illustrate only the principles of the present invention. Accordingly, it should be understood that those skilled in the art will be able to design various arrangements which, although not explicitly described or shown herein, embody the principles of the present invention and are included within its scope. In addition, all examples described herein are primarily for illustrative purposes only to assist the reader in understanding the principles of the present invention and the concepts contributed by the inventors to further the art, and should be construed as not being limited to these specifically recited examples and conditions. Additionally, unless otherwise stated (e.g., "otherwise" or "in an alternative"), the term "or" as used herein refers to a non-exclusive or. Moreover, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0053] Many innovative teachings of the present application will be described with particular reference to currently preferred exemplary embodiments. However, it should be understood that such embodiments merely provide several examples of the many useful applications of the innovative teachings herein. Generally, statements made in the specification of the present application do not necessarily limit any of the various claimed inventions. Additionally, some statements may apply to some inventive features but not to others. Those skilled in the art and those skilled in the art informed by the teachings herein will recognize that the disclosed content is also applicable to various other technical fields or embodiments.

[0054] To provide, for example, a small blood pump that improves manufacturability and minimizes the risk of thrombus formation, a blood pump with a specific flexible outflow cannula can be provided.

[0055] Referring Figure 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.

[0056] The blood pump can include a flexible outflow cannula 40 that can have 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.

[0057] An impeller 70 can be disposed within the pump housing and configured to rotate about a rotational axis for delivering blood from the blood flow inlet to the plurality of blood flow outlets.

[0058] Referring Figure 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 shown, in some embodiments, the conduit 30 can have an outer diameter 31, and the outer diameter 31 can be less than the outer diameter 21 of the pump housing 20.

[0059] In some embodiments, the flexible outflow cannula can include an intermediate portion 43 extending between a distal portion 41 and a proximal portion 42. The intermediate portion can have an outer diameter 44 that is greater than the outer diameter 21 of the pump housing.

[0060] The proximal portion 42 of the flexible outflow cannula can have a coupling portion 45 coupled to the conduit 30 and an uncoupled portion 46 extending distally from the coupling portion.

[0061] At least one slit 80 can be formed through the entire coupling portion 45 and extend to the proximal end of the flexible outflow cannula.

[0062] As used herein, "slit" refers to a separation or opening between adjacent portions of the coupling portion that are separated (or have been separated) in some manner (e.g., using a laser, cutting die, scissors, etc.). There may be some spacing or empty space volume between two adjacent portions. The two adjacent portions can overlap. The two adjacent portions can be connected in other ways such that there is no spacing or space volume separating the adjacent portions. In some embodiments, the two adjacent portions are separated by a distance greater than 1 micron. In some embodiments, the two adjacent portions are separated by a distance less than 1 micron. In some embodiments, the two adjacent portions are adjacent to each other.

[0063] In some embodiments, there can be only a single slit. In some embodiments, there can be two slits. In some embodiments, if there are two slits, they can be located on opposite sides of the outflow cannula (e.g., positioned 180 degrees around the central axis of the outflow cannula).

[0064] In some embodiments, the blood flow outlets 50, 60 can include one or more incised outlets 60, and the slit can be connected to the proximal end of at least one of the incised outlets. In some embodiments, the slit can be connected to the proximal end of the incised outlet 60 at the proximal end of the uncoupled portion 46. In some embodiments, the slit can extend distally from the coupling portion through at least a portion of the uncoupled portion and be connected to the proximal end of the incised outlet.

[0065] The incision outlet can extend distally from the unconnected portion and can have a tapered proximal portion 62.

[0066] In some embodiments, the plurality of blood flow outlets consists of four blood flow outlets 50, 60, and the incision outlet 60 consists of one or two of these four outlets. In some embodiments, the plurality of blood flow outlets can include four blood flow outlets 50, 60, where only one can be the incision outlet 60. In some embodiments, each of the plurality of blood flow outlets 50, 60 can be circumferentially equidistantly spaced apart from an adjacent blood flow outlet. That is, if there are three outlets, the centerline 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) can be offset 120 degrees from an adjacent outlet. If there are four outlets, the centerlines can be offset 90 degrees, five outlets can have a 72-degree offset, and so on.

[0067] In some embodiments, each of the plurality of blood flow outlets 50, 60 can be at least partially located in the middle portion 43 of the outflow cannula, and only the incision outlet 60 is at least partially located in both the proximal portion 42 of the outflow cannula and the middle portion 42 of the outflow cannula.

[0068] See Figure 3A , in some embodiments, each incision outlet can include a distal portion 61 and a proximal portion 62. Each incision 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.

[0069] The shape of the proximal portion can vary. For example, in some embodiments, the proximal portion 62 can form an incision having straight but non-parallel sides ( Figure 3A and Figure 3B ).

[0070] In some embodiments, the non-parallel sides form a V-shaped incision (see Figure 3A)。In some embodiments, the width 65 of the incision at the proximal end may be equal to the width of the slit 80 connected to the incision. In some embodiments, the width 65 of the incision at the proximal end may be less than the width of the slit 80 connected to the incision. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 1 mm. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 500 microns. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 250 microns. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 125 microns. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 50 microns. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 25 microns. In some embodiments, the width 65 of the incision at the proximal end may not be greater than 10 microns.

[0071] In some embodiments, the non-parallel sides may form an incision in the shape of a trapezoid (see Figure 3B ). In some embodiments, the width 65 of the incision at the proximal end may be greater than the width of the slit 80 but less than the width 66 of the middle part 63 of the incision. In some embodiments, the proximal part may form an incision with concave sides (see Figure 3C ). In some embodiments, the proximal part may form an incision with convex sides (see Figure 3D , 3E ).

[0072] In some embodiments, the proximal end of the incision may substantially reach a point ( Figure 3A , 3C , 3D). In some embodiments, the proximal end of the incision may be square or flat-ended ( Figure 3B ). In some embodiments, the proximal end of the incision may be circular ( Figure 3E ).

[0073] Referring to Figure 4A , in some embodiments, the slit 80 may be configured to allow at least a first portion 47 of the coupling portion 45 to overlap with a second portion 48 of the coupling portion. Referring to Figure 4B , in some embodiments, the slit 80 may be configured to prevent a first portion of the coupling portion of the proximal part from overlapping with a second portion of the coupling portion of the proximal part.

[0074] In some embodiments, the pump housing, the impeller, and any filters may each be alternately radially compressible and radially expandable.

[0075] Figure 5FIG. 0 is a partial cross-sectional view of an implantable blood pump 100 positioned within the left ventricle 102 of a patient's heart 104. However, in other applications, the implantable blood pump 100 may be positioned elsewhere within the patient's body, such as within the left atrium or elsewhere within the patient's vasculature, not necessarily within the heart 104. The blood pump 100 may include a catheter 106 and a pump portion 108 disposed at or near the distal end of the catheter 106.

[0076] The catheter 106 may be configured for insertion into a blood vessel (e.g., aorta 110) defining an internal volume 112 through which blood flows in a blood flow direction 114, indicated by the arrow. As used herein, the term "blood vessel" includes heart chambers or other internal cavities. The catheter 106 may be connected to a controller 116, such as an automated Impella controller ("AIC") available from Abiomed. The controller 116 may provide a user interface for controlling and monitoring the intravascular blood pump 100.

[0077] As used herein, the term "distal" refers to a 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 a direction or position along the catheter 106 toward the controller 116 or the user of the controller 116, as Figure 5 indicated by the arrows (distal 198, proximal 199).

[0078] During insertion, the intravascular blood pump 100 may be positioned to extend through the aortic valve 118, as Figure 5 shown, but in other applications, the intravascular blood pump 100 may be positioned elsewhere within the patient's vasculature, not necessarily within the heart 104. Additionally, although Figure 5 FIG. 0 depicts the intravascular blood pump 100 being inserted such that the blood flow direction 114 may be away from the distal end of the catheter 106, in other applications, the intravascular blood pump 100 may be inserted such that the blood flow direction 114 may 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 Figure 5 use shown, the leaflets of the aortic valve 118 close around the intravascular blood pump 100.

[0079] The intravascular blood pump 100 may be placed within the heart 104 using a percutaneous transluminal technique. For example, the intravascular blood pump 100 may be introduced through the femoral artery (not shown). However, alternative vascular access routes are also possible, such as access through the subclavian artery. After passing through the femoral artery, the catheter 106 may be advanced into the aorta 110 such that the pump portion 108 passes through the aortic valve 118 into the heart 104. Figure 1The positioning of the pump portion 108 therein is for illustration purposes only, and different placements are possible, such as positioning the pump portion 108 within the right ventricle of the heart 104.

[0080] A flexible atraumatic tip 120 having, for example, a pigtail or J-shaped form extends distally from the distal end of the pump portion 108. The atraumatic tip 120 should be soft enough to allow the pump portion 108 to support itself against the inner wall of the left ventricle 102 without trauma.

[0081] The pump portion 108 includes an impeller (not visible) disposed within a housing 122. The housing 122 and the impeller may or may not be expandable. The impeller may be mechanically coupled to an external motor 124 via a flexible drive shaft (reference numeral 202, not shown in this figure) extending through the catheter 106. The motor 124 may be in the controller 116 or elsewhere. Alternatively, the impeller may be mechanically coupled to a motor (not shown) disposed within the pump portion 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 to flow from a blood flow inlet (input port) 126 at the distal end of the pump portion 108 to a blood flow outlet (output port) 128 located proximal to the blood flow inlet 126, as indicated by the arrow. As noted, the term "internal volume" 112 includes heart chambers, such as the left ventricle 102.

[0082] The filter 130 may be arranged to provide fluid communication between: (a) the internal volume 112 of a blood vessel (in this case the left ventricle 102) external to the pump housing 122, and (b) the input port 126. Although the filter 130 is described in relation to an expandable housing 122 and an impeller, the filter 130 may also be used with a non-expandable housing 122 and an impeller.

[0083] The struts 300 - 304 used in the filter may be made of wire or other filaments. As Figure 6 and Figure 7 shown, the housing 122 may provide a cage around the impeller 200. When radially expanded ( Figure 6 ), the length 306 of the housing 122 may be less than the length 400 when the housing 122 can be radially compressed ( Figure 7 ). When the housing 122 expands, the change in length from 400 to 306 may be due to the deployment of the struts 300 - 304. In some embodiments, the change in length from 400 to 306 may be about 1 - 2 mm.

[0084] The expandable housing 122, the expandable impeller 200, and the expandable filter 130 can be held in their compressed state by a suitable compression sleeve 308 that slides over the expandable housing 122, the expandable impeller 200, and the expandable filter 130. The intravascular blood pump 100 having the expandable housing 122, the expandable impeller 200, and the expandable filter 130 can be delivered through the patient's vascular system with the housing 122, the impeller 200, and the filter 130 in their compressed state. Once the pump portion 108 is in its target position, the housing 122, the impeller 200, and the filter 130 can be allowed to expand, for example, by pushing the pump portion 108 out of the compression sleeve 308 in the forward (distal) direction or by pulling back (in the proximal direction) the compression sleeve 308. In the case of removing the compression sleeve 308, the housing 122 expands due to its shape memory, superelasticity, or hyperelastic properties, as Figure 6 shown. At the same time, the impeller 200 expands due to its elasticity. As the housing 122 expands radially away from the drive shaft 202, the housing 122 can longitudinally contract to a length 306.

[0085] The inner central portion of the housing 122 can have a sleeve or coating 310 (best shown in Figure 14 ) that defines a passage through which the impeller 200 can pump blood. Proximal and distal to this passage, the housing 122 can respectively allow blood to be drawn into the housing 122 and pushed out of the housing 122 into the outflow cannula.

[0086] When 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 pulled back into the compression sleeve 308, which causes the housing 122 to be radially compressed and can cause the housing 122 to longitudinally extend to a length 400. The filter 130 and the impeller 200 can also be compressed. The resulting smaller diameter of the housing 122 facilitates the removal of the intravascular blood pump 100 from the patient's body through the vasculature. Thus, the pump housing 122, the impeller 200, and the filter 130 are each configured to alternately radially compress and radially expand. Additional details of expandable intravascular blood pumps are provided in U.S. Patent No. 8,439,859, the entire contents of which are incorporated herein by reference for all purposes.

[0087] Figure 8 is in its expanded state Figure 6 and Figure 7Cross-sectional view of the inflatable housing 122 and the inflatable mesh filter 130. The housing 122 includes a number of parts connected to each other. These parts, from proximal to distal, are: a proximal tubular housing portion 500, a proximal tapered housing portion 502, an intermediate tubular housing portion 504, a distal tapered housing portion 506, and a distal tubular housing portion 508. As used herein, "tapered" means having a shape that smoothly and monotonically, but not necessarily linearly, changes in outer diameter. Thus, in profile, a tapered shape can include convex and / or concave portions. Tapers include, but are not limited to, conical shapes.

[0088] The proximal tubular housing portion 500 can be attached to the conduit 106 and contains a proximal bearing 510. The proximal tubular housing portion 500 has a generally cylindrical shape. The proximal tapered housing portion 502 connects the intermediate tubular housing portion 504 to the proximal tubular housing portion 500. The intermediate tubular housing portion 504 has an approximately cylindrical shape and surrounds the impeller 200. The exact cross-sectional shape of the intermediate tubular housing member 504 can depend on the number of struts 300 - 304 in the housing 122. Generally, the cross-sectional shape can be polygonal, possibly with rounded corners.

[0089] The distal tapered housing portion 506 connects the intermediate tubular housing portion 504 to the distal tubular housing portion 508 and defines the blood flow inlet (inlet port) 126 of the housing 122. The proximal tapered housing member 502 has a nearly circular cross-section with a radius increasing in the distal direction. Like the intermediate tubular housing member 504, the exact cross-sectional shape of the proximal tapered housing member 502 can depend on the number of struts 300 - 304, and generally, the cross-sectional shape can be polygonal, possibly with rounded corners.

[0090] Similarly, the distal tapered housing portion 506 also has an almost circular cross-section, however, its radius decreases in the distal direction. Like the intermediate tubular housing portion 504, the exact cross-sectional shape of the distal tapered housing portion 506 can depend on the number of struts 300 - 304, and generally, the cross-sectional shape can be polygonal, possibly with rounded corners.

[0091] The distal tubular housing portion 508 contains a distal support 512 and can be connected to the proximal side of the flexible atraumatic tip 120.

[0092] Inflatable filter

[0093] The expandable filter 130 may be mounted external to the expansion shell 122 and is thus shown in its expanded state. The filter 130 may include a distal tubular filter section 514 that has a relatively small diameter. The filter may include a proximal tubular filter section 516 that has a larger diameter. Like the intermediate tubular housing portion 504, the exact cross-sectional shape of the filter 130 (including the exact cross-sectional shape of the distal tubular filter section 514 and the proximal tubular filter section 516) may depend on the number of struts 300 - 304 and / or the number of struts in the filter 130. Generally, the cross-sectional shape may be polygonal, possibly with rounded corners.

[0094] A tapered filter section 518 may connect the two tubular filter sections 516 and 514. The expandable filter 130 may cover the entire distal tapered housing portion 506, i.e., the blood flow inlet (input port) 126, and its tapered filter section 518. The expandable filter may cover some of the intermediate tubular housing portion 504 with its proximal tubular filter section 516. In some embodiments, the expandable filter may cover some but not all of the distal tubular housing portion 508 with its distal tubular filter section 514. In some embodiments, the expandable filter may cover all of the distal tubular housing portion 508 with its distal tubular filter section 514.

[0095] A distal outer foil 520 may be disposed on top of the distal tubular filter section 514. The distal tubular filter section 514 may be disposed on top of the distal tubular housing portion 508. The distal outer foil 520 (or membrane) may prevent damage to the expandable filter 130. For example, if the expandable filter 130 is made of a strut mesh, the foil may prevent abrasion. If the distal tubular filter section 514 defines an aperture, the distal outer foil 520 may be directly attached via 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 may be made of the same or similar material, and the materials may be welded together via the aperture. Since the flexible atraumatic tip 120 may generally be made of polyether block amide (PEBA) or polyurethane, the distal outer foil 520 may also be made of PEBA or polyurethane, and the materials may be heat-sealed together.

[0096] The proximal outer foil 522 may be disposed on top of the intermediate tubular housing member 504. The proximal tubular section 516 of the expandable filter 130 may be clamped between the proximal outer foil 522 and the intermediate tubular housing portion 504, although only at the distal region of the proximal outer foil 522. The proximal outer foil 522 may prevent damage to the proximal tubular section 516 of the expandable filter 130. Additionally, the proximal outer foil 522 may be heat sealed through an aperture in the expandable filter 130 to the inner sleeve or coating 310 of the housing 122. The inner sleeve or coating 310 may be made of polyurethane (PU). When the inner sleeve or coating 310 is made of PU, the proximal outer foil 522 may preferably also be made of PU. When the filter 130 is made of a formed foil tube defining apertures, the proximal outer foil 522 may be made integrally with the filter 130.

[0097] The distal end of the flexible outflow cannula 204 may 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 apertures, the proximal outer foil 522 may be made integrally with the filter 130 and the flexible outflow cannula 204.

[0098] Spirally woven filament filter

[0099] Figure 9 Perspective view of the distal section of the intravascular blood pump 100, having an intermediate tubular housing portion 504, a distal conical housing portion 506, and a distal tubular housing portion 508. In this embodiment, the expandable filter 130 may be a mesh made of filaments woven or connected to each other. Weaving is a production method in which two different sets of filaments (warp and weft) are interlaced at an angle to form a fabric. The warp consists of longitudinal filaments, and the weft (or filling) consists of transverse filaments. The manner in which the warp filaments and weft filaments are interlaced with each other is called weaving. Most woven products are produced from one of three basic weaves: plain weave, satin weave, or twill weave.

[0100] In plain weave, the warp filaments and weft filaments cross at an angle and are arranged in a simple cross pattern. Each weft filament crosses the warp filaments, passes over one warp filament, and then passes under the next warp filament, and so on. The next weft filament passes under the warp and then over the adjacent warp, and vice versa. The filaments of the woven filter 130 are preferably of plain weave, but satin, twill, or other weaves may be used. Preferably, the mesh is not knitted and does not contain loops.

[0101] The characteristics of a satin weave can lie in that four or more weft filaments float on warp filaments, and four or more warp filaments float on a single weft filament. A float is a missed crossover point, for example, in a warp-faced satin, the warp filaments are at the top of the weft filaments. The characteristics of a twill weave can lie in a pattern of diagonal parallel ribs. A twill weave can be produced by passing a weft filament over one or more warp filaments and then under two or more warp filaments, and so on, with a "step" or offset between rows to produce the characteristic diagonal pattern.

[0102] Reference Figure 9 , the filter 130 can be made of filaments, represented by filaments 600, 602, 604, 608, 610, 612, 614, 616, and 618. Filaments 600 - 608 are a first set of substantially helical stays wound clockwise about the longitudinal axis 620 of the housing 122. As used herein, a "substantially helical" curve is a substantially smooth space curve. However, as used herein, the pitch, radius, curvature, and twist can vary along the length of the helical curve. The helical curve can, but need not, wind around the axis through more or less than 360 degrees. Additionally, a substantially helical curve can include minor zigzags, not necessarily all the same, as illustrated by substantially helical curves 714 and 716( Figure 10 ).

[0103] Returning to Figure 9 , filaments 610 - 618 can be a second set of substantially helical stays wound counterclockwise about the longitudinal axis 620. Filaments 600 - 618 are represented by thick dashed lines to make them more visible in the figure. For clarity, these filaments 600 - 618 are also reproduced in the inset in Figure 9 . The first set of stays 600 - 608 and the second set of stays 610 - 618 together define a plurality of orifices therebetween, represented by orifices 622, 624, and 626. The first set of stays 600 - 608 and the second set of stays 610 - 618 are woven together such that the plurality of orifices 622 - 626 are defined between corresponding adjacent first woven filaments 600 and second woven filaments 618.

[0104] Each orifice in at least one subset of the plurality of orifices 622 - 626 can have a generally diamond or rhomboid or rectangular shape. As used herein, a rhomboid is a parallelogram in which adjacent sides have unequal lengths and the angle between adjacent sides is non - right. As used herein, a diamond is a parallelogram in which adjacent sides have equal lengths and the angle between adjacent sides is non - right. Rhomboids, diamonds, and rectangles are not necessarily planar. Rhomboids, diamonds, and rectangles can exist on a curved surface, as illustrated by orifices 622 - 626. The sides of a rhomboid, diamond, or rectangle do not need to be perfectly straight, and the sides do not necessarily need to meet at corners, i.e., there can be a small radius where two sides meet relative to the corners in the orifices defined by the formed foil tube filter, as discussed in more detail below.

[0105] In at least an intermediate portion 628 of the conical filter section 518, the orifices 622 - 626 can preferably be of an approximately square shape. As the diameter of the filter 130 decreases, e.g., in the distal direction within the conical filter section 518, the orifices 622 - 626 can gradually become smaller, and the orifices can become rhomboid - shaped with their major axis extending longitudinally. At the minimum diameter of the conical filter section 518, the smaller interior angle of a diamond or rhomboid orifice can be less than about 75°.

[0106] As the diameter of the filter 130 increases, e.g., in the proximal direction within the conical filter section 518, the orifices 622 - 626 can gradually become larger. At the maximum diameter of the conical filter section 518, the larger interior angle of a diamond or rhomboid orifice can be greater than about 110°. The orifices can become rhomboid - shaped with their major axis extending circumferentially. These numbers correspond to an embodiment where the larger diameter of the filter 130 is about 2.5 times the smaller diameter of the filter 130. For other ratios of the large diameter to the small diameter of the filter 130, the angles can be adjusted.

[0107] The pump housing 122 can be configured to longitudinally elongate by an amount that depends on the amount by which the pump housing 122 is radially compressed. The filter 130 can be configured to longitudinally elongate by an amount that depends on the amount by which the filter 130 is radially compressed. The filter 130 can be configured such that for a given amount of radial compression, the filter 130 and the pump housing 122 longitudinally elongate by approximately equal amounts.

[0108] The filaments 600-618 can be wires (such as nitinol), suitable polymers (such as polyethylene terephthalate (PET) or PU), fibers, or another suitable material. The filaments 600-618 material is preferably a shape memory material. The individual filaments 600-618 can have a thickness between about 10 μm and about 80 μm, or between about 20 μm and about 60 μm, for example about 40 μm. The catheter 106, pump housing 122, impeller 200, and filter 130 are configured for use in a living patient such that the size of each of the plurality of orifices 622-626 is designed to prevent the input port 126 from ingesting the heart tissue of the living patient.

[0109] In some embodiments where the filter 130 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 fuse the intersecting filaments 600-618, especially if the filaments 600-618 are made of a suitable heat-fusible plastic. Such fused filaments 600-618 form a stronger mesh.

[0110] In some embodiments, when the filter 130 is in the expanded state, the woven fabric has a maximum distance between two adjacent filaments 600-618 between about 0.3 mm (300 μm) and about 0.4 mm (400 μm). In some embodiments, when the filter 130 is in the expanded state, each of the plurality of orifices 622-626 has a maximum size less than or equal to about 0.5 mm (500 μm). In some embodiments, when the filter 130 is in the expanded state, each of the plurality of orifices 622-626 has a maximum size less than or equal to about 0.4 mm (400 μm). In some embodiments, when the filter 130 is in the expanded state, each of the plurality of orifices 622-626 has an area less than or equal to about 0.09 mm 2 In some embodiments, when the filter 130 is in the expanded state, each of the plurality of orifices 622-626 has an area less than or equal to about 0.16 mm 2 In some embodiments, when the filter 130 is in the expanded state, each of the plurality of orifices 622-626 has an area less than or equal to about 0.16 mm.

[0111] As used herein, "maximum size" includes diagonal dimensions, such as the dimension between two opposite oblique corners 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 tangent to the boundary of the convex shape. As used herein, "width" means the smallest such distance.

[0112] Heterogeneous foil tube filter

[0113] Figure 10 is a side view of the expandable filter 130 formed by the filter tube, Figure 11is an axial (longitudinal) view thereof. In some embodiments, the tube can be a generally funnel-shaped tube. Figure 10 An insert including an enlarged portion showing the expandable filter 130. As noted, in some embodiments, the filter 130 includes a formed foil tube 700 having apertures. The apertures can be openings through the wall forming the tube. The wall can be, for example, 10-100 μm thick. Examples of apertures are shown at 702, 704, and 706. The expandable filter 130 made of the formed foil tube 700 can be compressed by folding some or all of the parts of the filter 130, i.e., becoming smaller radially. The filter 130 can be expanded from its compressed state by unfolding the previously folded parts. The compression and expansion mainly rely on this folding and unfolding, rather than elastic compression and elongation.

[0114] The apertures 702-706 can be positioned on the tube such that the material between the apertures 702-706 (exemplified by materials 708, 710, and 712) forms a first strut and a second strut. Two exemplary struts 714 and 716 are shown in Figure 10 in thick dashed lines. As noted, a generally helical curve can include small zigzags, not necessarily all the same, as exemplified by the generally helical curves 714 and 716. These zigzags are seen more clearly in the Figure 10 insets in, for example, struts 718 and 720, which are indicated by thick solid and dashed lines.

[0115] Figure 10 and Figure 11 show the expanded filter 130 when the filter 130 is mounted on an expanded housing 122 (e.g., Figure 9 ), although the housing 122 is not shown in Figure 10 and Figure 11 . The filter 130 made of the formed foil tube 700 can be made of a polymer, such as PET or PU. The wall of the foil tube 700 can be about 10 μm to about 100 μm thick, preferably about 15 μm to about 75 μm thick, and more preferably about 20 μm to about 50 μm thick. The thickness of the wall of the foil tube 700 can continuously decrease in the distal direction in the conical filter section 518, for example, manufactured by blow molding.

[0116] As Figure 12 shown, the foil tube 700 can be formed on a mandrel 900. The mandrel 900 should have the desired shape of the finished filter 130 in the expanded state. Then the apertures 702-706 can be defined in the formed tube, for example, by cutting or stamping. The apertures 702-706 can have a generally diamond or oblong or rectangular shape. The inner corners of the apertures 702-706 in the filter 130 based on the foil tube 700 should have a radius of at least about 5 μm and preferably at least about 20 μm.

[0117] Additional holes can be defined in the formed tube to facilitate attachment of the formed tube to other components of the intravascular blood pump 100, as discussed herein. The formed perforated tube can then be mounted on the housing 122, as Figures 13 - 15 shown (the housing 122 is not visible in Figure 15 ). Figure 13 is a cross-sectional view of the distal region of the expandable housing 122 on which the expandable filter 130 is mounted. Figure 14 is a cross-sectional view as in Figure 13 ; however, it includes an expandable housing inner coating 310 which is not shown in Figure 13 for clarity. Figure 15 is a perspective view of the distal region of the expandable housing 122 on which the Figures 10 - 11 expandable filter is mounted.

[0118] Returning to Figure 10 and Figure 11 , the shape and size of the holes can vary in different portions of the expandable filter 130. In the distal tubular filter section 514, the holes exemplified by the holes 722 can 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 Figure 10 shown. This staggering and overlapping enables the distal tubular section 514 to be easily expanded during assembly without elastic stretching of the material. This expansion can facilitate insertion of the impeller 200 through the distal end of the housing 122 into the housing 122. Additionally, this staggering generally enables the holes 722 to be arranged closer together, thus making the filter 130 more transparent to blood flow.

[0119] The distal outer foil 520 ( Figure 13 ) can be heat-sealed, for example by welding, through the holes 722 of the distal tubular filter section 514 to extend to the proximal section of the flexible atraumatic tip 120. Each hole 722 in the distal tubular filter section 514 has an enlarged portion centered in a longitudinal slot. After insertion of the impeller 200 and the distal tubular section 514 returns to its normal diameter, the enlarged portion advantageously has a relatively large opening contact area for attaching the distal outer foil 520 to the flexible atraumatic tip 120.

[0120] The expandable filter 130 further includes a transition region 724 where the distal tubular filter section 514 and the tapered filter section 518 meet ( Figure 10)。The holes in the transition region 724 (illustrated by hole 726) are longer and wider than the adjacent holes in the conical filter section 518. Preferably, the holes 726 in the transition region 724 are at least twice as large as the adjacent holes (illustrated by hole 728) in the conical filter section 518. In one embodiment, for each pair of circumferentially adjacent holes 728 in a row of the conical filter section 518, the transition region 724 has one hole 726 that circumferentially spans two holes 728. Thus, the number of holes in a circumferential row in the transition region 724 can be half the number of holes in a circumferential row in the conical filter section 518. In some other embodiments, other ratios may be used, such as 3:1, 4:1, or 3:2. Depending on the ratio of the number of holes 728 in a row of the conical filter section 518 to the number of holes 726 in a row of the transition region 724, each hole 726 in the transition region 724 can be approximately twice, three times, or another multiple as long (in the longitudinal direction) and approximately twice, three times, or another multiple as wide (in the circumferential direction) as the holes 728 in the conical filter section 518.

[0121] The sizes and shapes of the holes 702 - 706 and 728 and the sizes of the struts 714 - 716 should be selected such that when the conical filter section 518 is fully open, the housing 122 can be inserted into the conical filter section 518 without exceeding the limits of elastic deformation of the material. For example, considering any local elastic deformation of the filter material, the length of two circumferentially adjacent struts 714 - 716 (on the zigzag of the zigzag circumferential ring) multiplied by the number of orifices 702 - 706 in a circumferential row should be approximately equal to the circumference of the fully expanded housing 122.

[0122] The adjacent holes 726 in the transition region 724 are separated from each other by struts that are wider than the adjacent struts 714 - 716 of the conical filter section 518. These wider struts stabilize the larger holes 726. When the distal outer foil 520 is placed on the distal tubular filter section 514, longitudinally proximal up to the transition region 724, the distal outer foil 520 at least partially covers the first row or rows of holes 726 in the transition region 724 and thus reduces their effective size. In some cases, these reduced hole sizes may result in blood damage or an increased risk of clotting. Therefore, the holes 726 in the transition region 724 should be selected to be larger than the holes in the conical filter section 518.

[0123] As can be seen in Figure 10As can be seen, the holes 728 in the distal region of the conical filter section 518 are narrower in the circumferential direction than the holes 702 - 706 in the proximal region of the conical filter section 518. In other words, the sizes of the orifices 702 - 706 increase monotonically in the proximal direction along the longitudinal axis. Further, in the distal tubular filter section 514, the holes 722 are in the form of narrow axial slits which are offset from each other in the circumferential direction. This is advantageous because when the expandable filter 130 expands at the distal tubular filter section 514 and the distal region of the conical filter section 518, e.g., when the impeller 200 is inserted into the housing 122, the narrow holes may widen. The wider holes are defined by thicker struts, particularly in the conical filter section 518. The width of the struts is between about 30 μm in the distal region of the conical filter section 518 and about 60 μm in the proximal region. Preferably, the maximum diameter of the holes in the conical filter section 518 is between about 300 μm and about 500 μm.

[0124] In Figure 10 the illustrated embodiment, the proximal tubular filter section 516 does not have holes. However, holes in the proximal tubular filter section 516 may be desirable, e.g., when the proximal outer foil 522 is placed on the proximal tubular filter section 516 ( Figure 8 ), the proximal tubular filter section 516 may in turn be located on the intermediate tubular housing portion 504. The proximal outer foil 522 secures the expandable filter 130 to the housing 122, and since the tubular housing member 504 may be coated with PU and the proximal outer foil 522 may also be made of PU, they may be easily heat sealed or welded together through such holes. However, if both the filter 130 and the proximal outer foil 522 are made of compatible materials, e.g., PU, the filter 130 and the proximal outer foil 522 may be directly joined together, e.g., by applying heat.

[0125] When Figure 10 and Figure 11 the expandable filter 130 in Figure 13 is disposed on the expanded housing 122, e.g., as

[0126] shown, the distal tubular filter section 514 may preferably be disposed on top of the distal support 512 and the flexible atraumatic tip 120. The distal tubular filter section 514 may be covered with a distal outer foil 520 to fasten the expandable filter 130 to the intravascular blood pump 100.

[0126] The proximal tubular filter section 516 has a relatively large diameter. If this diameter is not likely to change significantly during the assembly of the intravascular blood pump 100, i.e., the proximal opening of the filter 130 is not likely to be significantly stretched, any holes defined in this portion during assembly will not be significantly deformed. Thus, these holes may be square or another shape, and the holes may be at least partially defined by a circumferential ring of struts.Figure 16 An embodiment is shown. Figure 16 is of an alternative embodiment according to the present invention Figure 10 and Figure 11 side view of the expandable filter 130 of

[0127] Figure 16 The expandable filter 130 of includes a strip 1300 composed of several parallel pore rings exemplified by pores 1302, 1304, and 1306 and rings 1308 and 1310. All rings 1308 - 1310 have the same number of pores 1302 - 1306, and the pores 1302 - 1306 are of substantially equal size. Thus, the ratio of the total pore area to the total strut area within the strip 1300 can be relatively high compared to other parts of the filter 130. A high pore - strut ratio can be advantageous because it makes the filter 130 more transparent to blood flow, which reduces the risk of hemolysis and coagulation. The ratio of the total pore area exposed to blood to the total area of the filter 130 should be at least about 60%, preferably at least about 70%, and more preferably at least about 80%. The strip 1300 can be combined with the large pores 726 in the transition zone 724 discussed herein with respect to Figure 10 discussed.

[0128] A description of the pore and orifice shapes is given for the expandable filter 130. When the filter 130 is compressed, for example by folding, the pore shape may change drastically. In fact, it is the ability of the struts to bend that makes the filter 130 easy to compress.

[0129] Figure 17 is Figures 13 - 14 perspective view of the distal region of the expandable housing of on which is mounted an expandable filter similar to Figures 10 - 11 and / or Figure 16 but having a different orifice pattern. For example, some struts are bifurcated, as exemplified by strut 1400. Some struts, such as the forked strut 1400, can be wider than other struts. Some struts, exemplified by struts 1402 and 1404, extend between the respective pairs of teeth of the fork. Thus, a plurality of first struts and a plurality of second struts extend between a pair of teeth and jointly define a plurality of orifices therebetween. Each first strut including a fork can be wider than each first strut not including a fork.

[0130] Optionally, one or more of the struts may be aligned above the corresponding struts of the housing 122. As Figure 13 shown, the housing 122 includes struts represented by struts 300, as discussed with respect to Figure 6 and Figure 7 discussed. The housing struts 300 are referred to herein as third struts. The group of these third struts represented by struts 1000 ( Figure 13 ) jointly define orifices therethrough, by orifices 1002 (Figure 13 ) is indicated. At least some of the first struts and the second struts, i.e., the struts in the filter (see Figure 10 ), such as the forked strut 1400 ( Figure 17 ), are radially aligned with corresponding struts in the third strut for support.

[0131] Figure 18 is of the distal region of an expandable housing according to another alternative embodiment of the present invention Figures 13 - 14 in perspective view, on which is mounted an expandable filter similar to Figure 17 but having a different orifice pattern.

[0132] Figure 19 is a side view of the distal region of an expandable housing according to yet another alternative embodiment of the present invention Figures 13 - 14 on which is mounted an expandable filter similar to Figure 17 .

[0133] Figure 20 is Figures 13 - 14 a side view of the distal region of an expandable housing having a long inflow cannula 1701 and a spherical expandable filter 1700, the spherical expandable filter 1700 having an enlarged inflow region 1702 mounted thereon. Figure 21 is Figures 13 - 14 a side view of the distal region of an expandable housing showing the outflow cannula and no long inflow cannula, and a spherical expandable filter 1800, the spherical expandable filter 1800 having an enlarged inflow region 1802 mounted thereon but otherwise similar to Figure 20 .

[0134] The spherical expandable filters 1700 and 1800 provide enlarged inflow regions 1702 and 1802 to the intravascular blood pump 100, which improves the flow characteristics of the pump. The enlarged inflow regions 1702 and 1802 are covered by filters 1704 similar to Figures 13 - 15 but having larger orifices.

[0135] The filter 130 includes a distal portion 1706 and a proximal portion 1708. The diameter of the distal portion 1706 increases monotonically in the proximal direction along the longitudinal axis. The diameter of the proximal portion 1708 decreases monotonically in the proximal direction along the longitudinal axis.

[0136] At least some of the plurality of orifices 702 - 706 may be provided on the distal portion 1706. In some embodiments, the proximal portion 1708 may be without orifices.

[0137] Typically, the apertures among the plurality of apertures 702 - 706 increase in size in the distal direction along the longitudinal axis, although this increase is not necessarily monotonic. The apertures 702 - 706 are arranged relative to the longitudinal axis as a plurality of generally circumferential rows of apertures of generally equal size, illustrated by rows 1710, 1712, and 1714. Some of the rows 1710 - 1714 have a different number of apertures 702 to 706 than other rows of rows 1710 - 1714. For example, the first row 1710 (indicated by the dashed line) of the plurality of generally circumferential rows includes more apertures 702 than the second row 1712 of the plurality of generally circumferential rows. Each aperture 702 of the first row 1710 has a smaller area than each aperture 704 of the second row 1712.

[0138] The apertures 702 - 706 can be arranged relative to the longitudinal axis as a plurality of generally circumferential bands of apertures of generally equal size, 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, typically, the apertures in band 1720 are larger than the apertures in band 1718. However, the apertures in a given row can be larger or smaller than the apertures in another row of the same band because although the two rows have the same number of apertures, the two rows can have different circumferences. In Figure 20 the illustrated embodiment, the size of the apertures 702 - 706 in each of the plurality of bands 1718 - 1722 increases monotonically in the distal direction along the longitudinal axis. Other aspects of the aperture size and arrangement are similar to those discussed with respect to Figure 10 those.

[0139] As noted, Figure 21 the distal region of the inflatable housing shown in Figure 20 is similar to the distal region shown in Figure 21 except that the inflatable housing in

[0140] Figure 22 is Figures 13 - 14 a perspective view of the distal region of the inflatable housing of Figure 17 which has an inflatable filter similar to that of Figure 22Only one longitudinal brace 1900 is shown, but the filter 130 may include additional longitudinal braces (not shown).

[0141] In some embodiments, the blood pump may have an elastically radially compressible ("crimpable") pump housing and, in some cases, a radially compressible impeller to facilitate insertion of the pump into a patient. When the blood pump and the impeller are in a compressed state, the compressible housing blood pump can be inserted into the patient, and then, after the blood pump is properly positioned, the pump housing and the impeller can be allowed to radially expand.

[0142] Figure 23 is a graphical illustration of an example of such a process. Figure 23 A side view is provided of the blood pump 2300 in six stages ((1) to (6)) of being exposed from the tubular sheath 2310 as the tubular sheath 2310 is withdrawn relative to the blood pump 2300 as shown by the arrow 2312. When the tubular sheath 2310 can be withdrawn, portions of the blood pump 2300, particularly the mesh structure 2302 and the impeller 2304, elastically radially expand, and the pigtail 2306 coils.

[0143] Figure 24 is a flow chart schematically showing a method 2400 for crimping a blood pump. The method 2400 can be practiced, for example, using a crimping tool known in the art. The method includes setting 2402 the blood pump within the distal end of a tapered longitudinal tube bore. The tube bore can be defined by an elongate tube. The tube bore can be at least about 30 mm long. The tube bore can have an internal dimension that tapers from (a) at least about the maximum external dimension of the pump at the distal end of the tube bore to (b) a diameter of at most about 4 mm at the proximal end of the tube bore.

[0144] At 2404, the blood pump can be translated through the tube bore in a direction toward the proximal end of the tube bore, including 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 crimping the blood pump to produce a crimped blood pump.

[0145] In some embodiments, translating the blood pump can include pulling the blood pump through the tube bore. However, in principle, translating the blood pump can involve pushing the blood pump through the tube bore.

[0146] In some embodiments, the internal dimension of the distal end of the tube bore can be at least about 7 mm. In some embodiments, the internal dimension of the proximal end of the tube bore can be at most about 4 mm. In some embodiments, the internal dimension of the distal end of the tube bore can be at least about 7 mm and the internal dimension of the proximal end of the tube bore can be at most about 4 mm. In some embodiments, the tube bore can be at least about 50 mm long. In some embodiments, the tube bore can be at least about 100 mm long. In some embodiments, the tube bore can be at least about 170 mm long. In some embodiments, the tube bore can be at least about 300 mm long.

[0147] Optionally, the inner wall of the tube defining the tapered tube bore may extend at an angle of less than about 2° relative to the longitudinal axis of the tube. Optionally, the taper ratio of the tapered tube bore may be no greater than about 1:14, the taper ratio being 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.

[0148] Optionally, at 2406, the tubular sheath may be disposed substantially coaxially with the proximal end of the tube bore.

[0149] Optionally, at 2408, the crimped blood pump may be translated from the proximal end of the tube bore to the tubular sheath with substantially no change in the outer dimensions of the crimped blood pump. Translating the crimped blood pump from the proximal end of the tube bore 2408 to the tubular sheath may include: (a) releasably constraining 2410 the distal portion of the tubular sheath in a hub. The hub is attached to the proximal end of the tube. The hub defines a hub bore that is coaxial with the tube bore. One end of the hub bore is coupled to the proximal end of the tube bore. The other end of the hub bore is configured to receive the distal portion of the tubular sheath substantially coaxially with the tube bore. Translating the crimped blood pump from the proximal end of the tube bore 2408 to the tubular sheath may further include: (b) translating 2412 the crimped blood pump through the hub bore. Optionally, the method further includes releasing 2414 the distal portion of the tubular sheath from the hub.

[0150] Optionally, the method includes translating 2416 the crimped blood pump out of the tubular sheath and into the patient's vasculature and allowing the crimped blood pump 2418 to elastically expand within the vasculature.

[0151] Figure 25 is a flow chart schematically showing another method 2500 for crimping a blood pump. For example, method 2500 may be implemented using a frangible crimping tool known in the art. Method 2500 includes disposing 2502 the blood pump within the distal end of a tapered longitudinal tube bore. The tube bore may be defined by an elongate tube. The proximal end of the tube may be coaxially and frangibly attached to the distal end of a tubular sheath. The tubular sheath may have an internal dimension (e.g., inner diameter). The tube bore may be at least about 30 mm in length. The tube bore may have an internal dimension that tapers from (a) at least approximately the maximum outer dimension of the blood pump at the distal end of the tube bore to (b) the internal dimension of the tubular sheath at approximately the proximal end of the tube bore.

[0152] At 2504, the blood pump may be translated through the tube bore in a direction toward the proximal end of the tube bore, including 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 crimping the blood pump to produce a crimped blood pump. At 2506, the crimped blood pump may be translated from the proximal end of the tube bore to the tubular sheath with substantially no change in the outer dimensions of the crimped blood pump. At 2508, the tubular sheath may be frangibly separated from the tube, with the crimped blood pump disposed within the tubular sheath.

[0153] Although the present invention has been described by way of the above exemplary embodiments, modifications and variations can be made to the illustrated embodiments without departing from the inventive concept disclosed herein. For example, although specific parameter values such as dimensions and materials may be recited with respect to the disclosed embodiments, within the scope of the present invention, the values of all parameters can vary within a wide range to accommodate different applications. Unless otherwise specified in the context or understood by one of ordinary skill in the art, terms such as "about" mean within ±20%.

[0154] As used herein (including in the claims), the term "and / or" used in conjunction 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" used in conjunction 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".

[0155] The disclosed aspects or portions thereof can be combined in ways not listed and / or not explicitly claimed above. In addition, the disclosed embodiments can be practiced appropriately in the absence of any element not specifically disclosed herein. Accordingly, the present invention should not be considered limited to the disclosed embodiments.

[0156] As used herein, numerical terms such as "first", "second", and "third" are used to distinguish the respective braces, rings of the orifices, and / or bands of the orifices from one another and are not intended to indicate any particular order or total number of braces, rings of the holes, and / or bands of the holes in any particular embodiment. Thus, for example, a given embodiment may include only a second brace, ring of the orifice, and / or band of the orifice and a third brace, ring of the orifice, and / or band of the orifice.

Claims

1. A blood pump, comprising: A pump housing having a blood flow inlet; A catheter operably coupled to the proximal end of the pump housing, the outer diameter of the catheter being smaller than the outer diameter of the pump housing; A flexible outflow cannula having a proximal portion operably coupled to the catheter, a plurality of blood flow outlets, and a distal portion operably coupled 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 about a rotational axis for pumping blood from the blood flow inlet to the plurality of blood flow outlets; Wherein the proximal portion of the flexible outflow cannula has a coupling portion coupled to the catheter and an uncoupled portion extending distally from the coupling portion; Wherein at least one slit is formed through the entire coupling portion and extends to the proximal end of the flexible outflow cannula; Wherein the plurality of blood flow outlets includes one or more incised outlets; and Wherein the slit is connected to the proximal end of at least one of the incised outlets, the incised outlet having a tapered proximal end and extending distally from the uncoupled portion.

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

3. The blood pump according to claim 1, wherein, The plurality of blood flow outlets consists of four blood flow outlets, and wherein the four blood flow outlets have exactly one incised outlet or exactly two incised outlets.

4. The blood pump according to claim 3, wherein, The four blood flow outlets exactly have one incised outlet.

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

6. The blood pump according to claim 5, wherein, Each of the plurality of blood flow outlets is at least partially located within the intermediate portion, and only the incised outlet is at least partially located within both the proximal portion and the intermediate portion.

7. The blood pump according to claim 1, wherein, The flexible outflow cannula is defined by a substantially tubular member having a sidewall thickness of less than 20 microns.

8. The blood pump according to claim 1, wherein, Each of the incised outlets 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.

9. The blood pump according to claim 8, wherein, The proximal portion of the incised outlet forms an incision having straight non-parallel sides.

10. The blood pump according to claim 8, wherein, The proximal portion of the incised outlet forms an incision having concave sides.

11. The blood pump according to claim 8, wherein, The proximal portion of the incised outlet forms an incision having convex sides.

12. The blood pump according to claim 8, wherein, The width of the proximal end of the proximal portion is equal to the width of the slit across the coupling portion.

13. The blood pump according to claim 8, wherein, The width of the proximal end of the proximal portion is greater than the width of the slit across the coupling portion.

14. The blood pump according to claim 1, further comprising a filter in fluid communication between (a) an internal volume of a blood vessel into which the blood pump is inserted outside the pump housing and (b) the blood flow inlet, the filter including a plurality of generally helical first struts and a plurality of second struts wound around a longitudinal axis, the first struts and the second struts together defining a plurality of orifices therebetween.

15. The blood pump according to claim 14, wherein, The pump housing, the impeller, and the filter are each alternately radially compressible and radially expandable.

16. The blood pump according to claim 15, wherein, The pump housing is configured to longitudinally elongate by an amount when radially compressed, the amount depending on the amount by which the pump housing is radially compressed, and the filter is configured to longitudinally elongate by an amount when radially compressed, the amount depending on the amount by which the filter is radially compressed, such that for a given amount of radial compression, the filter and the pump housing longitudinally elongate by approximately equal amounts.

17. The blood pump according to claim 15, wherein, The conduit, the pump housing, the impeller, and the filter are configured for use in a living patient's body such that the size of each of the plurality of apertures is designed to prevent the blood flow inlet from ingesting the heart tissue of the living patient.

18. The blood pump according to claim 15, wherein, Each of the plurality of apertures has a maximum size that is less than or equal to about 0.5 mm.

19. The blood pump according to claim 15, wherein, Each of the plurality of apertures has a maximum size that is less than or equal to about 0.4 mm.

20. The blood pump according to claim 15, wherein, Each of the plurality of orifices has an area less than or equal to about 0.09 mm 2 .

21. The blood pump according to claim 15, wherein, Each of the plurality of orifices has an area less than or equal to about 0.16 mm 2 .

22. The blood pump according to claim 15, wherein, The plurality of apertures have sizes that increase monotonically along the longitudinal axis.

23. The blood pump according to claim 15, wherein, The generally helical first struts wind clockwise about the longitudinal axis, and the second struts wind generally helically counterclockwise about the longitudinal axis.

24. The blood pump according to claim 15, wherein, The generally helical first struts wind about the longitudinal axis in a first direction, and the second struts wind generally helically about the longitudinal axis in the first direction.

25. The blood pump according to claim 15, wherein, Each strut in at least one subgroup of the second struts lies in a respective plane containing the longitudinal axis.

26. The blood pump according to claim 15, wherein, Each aperture in at least one subset of the plurality of apertures has a generally diamond or rhomboid shape.

27. The blood pump according to claim 15, wherein, The generally helical first struts include a plurality of first filaments, the second struts include a plurality of second filaments, and the first filaments and the second filaments are woven together such that the plurality of apertures are defined between respective adjacent first woven filaments and second woven filaments.

28. The blood pump according to claim 15, wherein, The filter includes a tube having a wall, wherein the plurality of apertures include a plurality of openings defined through the wall.

29. The blood pump according to claim 28, wherein, The tube includes a generally funnel-shaped tube.

30. The blood pump according to claim 28, wherein, The wall is about 10 - 100 μm thick.

31. The blood pump according to claim 28, wherein, The pump housing includes a plurality of third struts that together define a plurality of third apertures therebetween, and at least some of the first struts and the second struts are radially aligned on respective third struts of the third struts.

32. The blood pump according to claim 28, wherein, Each strut in at least one subgroup of the first struts includes a forked portion that includes a plurality of pointed teeth, wherein a plurality of the first struts and a plurality of the second struts extend between a pair of pointed teeth and together define a plurality of apertures therebetween.

33. The blood pump according to claim 32, wherein, Each first strut that includes a forked portion is wider than each first strut that does not include a forked portion.

34. The blood pump according to claim 28, wherein, The plurality of apertures are arranged in a plurality of generally circumferential rows of apertures of equal size relative to the longitudinal axis, wherein some of the rows have a different number of apertures than other rows of the rows.

35. The blood pump according to claim 34, wherein, The first row of the plurality of generally circumferential rows includes more apertures than the second row 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.

36. The blood pump according to claim 28, wherein, The orifices are arranged in a band of a plurality of substantially circumferential orifices of substantially equal size relative to the longitudinal axis, wherein the size of the orifices in each of the plurality of bands increases monotonically along the longitudinal axis.

37. The blood pump according to claim 36, wherein, The filter includes a distal portion and a proximal portion, the diameter of the distal portion increases monotonically in the proximal direction along the longitudinal axis, the diameter of the proximal portion decreases monotonically in the proximal direction along the longitudinal axis, and at least a portion of the plurality of orifices are provided on the distal portion.

38. The blood pump according to claim 14, wherein, There are no circumferential struts relative to the longitudinal axis for the substantially helical first strut and the second strut.

39. The blood pump according to claim 1, wherein, The slit is configured to allow at least a first portion of the coupling portion of the proximal portion to overlap a second portion of the coupling portion of the proximal portion.

40. The blood pump according to claim 1, wherein, The slit is configured to prevent a first portion of the coupling portion of the proximal portion from overlapping a second portion of the coupling portion of the proximal portion.

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