CN117120137A

CN117120137A - Intravascular blood pump and pump with expandable stent

Info

Publication number: CN117120137A
Application number: CN202280019353.9A
Authority: CN
Inventors: M·卡洛梅尼; 布莱恩·D·布兰特; A·瑞安; 雷扎·谢拉兹; 格雷戈里·迈克尔·哈梅尔; D·希尔德布兰德; 斯宾塞·诺伊
Original assignee: Shifamed Holdings LLC
Current assignee: Shifamed Holdings LLC
Priority date: 2021-03-05
Filing date: 2022-03-07
Publication date: 2023-11-24

Abstract

A catheter blood pump comprising an expandable pump portion. The pump portion includes a collapsible blood conduit defining a blood lumen. The collapsible blood conduit includes a collapsible stent adapted to provide radial support to the blood conduit. The pump section also includes one or more impellers. The collapsible bracket may include portions having different radial stiffness based on the position of one or more impellers therein.

Description

Intravascular blood pump and pump with expandable stent

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No. 63/157,360 entitled "CATHETER BLOOD PUMPS AND COLLAPSIBLE BLOOD CONDUITS (catheter blood pump and collapsible blood tubing)" filed on day 3,5, 2021 and U.S. provisional application No. 63/193,544 entitled "INTRAVASCULAR BLOOD PUMPS AND PUMPS WITH EXPANDABLE SCAFFOLDS (intravascular blood pump and pump with expandable stent)" filed on day 26, 2021, which are incorporated herein by reference in their entirety.

Incorporated by reference

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

Background

The ability of patients with heart disease to drive blood flow through the heart and vasculature may be severely compromised, for example, with substantial risk during corrective procedures such as balloon angioplasty and stent delivery. There is a need for ways to improve the cardiac outflow or stability of these patients, especially during corrective procedures.

Intra-aortic balloon counterpulsation (IABP) is commonly used to support circulatory functions, such as treating heart failure patients. The use of IABP is commonly used in the treatment of heart failure patients, for example to support the patient during High Risk Percutaneous Coronary Intervention (HRPCI), to stabilize patient blood flow after cardiogenic shock, to treat patients associated with Acute Myocardial Infarction (AMI), or to treat decompensated heart failure. Such circulatory support may be used alone or in combination with drug therapy.

The IABP generally works by being placed in the aorta and inflated and deflated in counterpulsation with systole, and one of the functions is to attempt to provide additional support to the circulatory system.

Recently, minimally invasive rotary blood pumps have been developed that can be inserted into the body in conjunction with the cardiovascular system, such as pumping arterial blood from the left ventricle into the main artery, to increase the natural blood pumping capacity of the left side of the patient's heart. Another known method is to pump venous blood from the right ventricle to the pulmonary artery to increase the natural blood pumping capacity of the right side of the patient's heart. The general goal is to reduce the workload on the patient's myocardium to stabilize the patient, for example, during medical procedures where additional pressure may be applied to the heart, to stabilize the patient prior to heart transplantation, or to continuously support the patient.

The smallest rotary blood pumps currently available can be inserted percutaneously through an access sheath into the vasculature of a patient, thereby eliminating the need for surgical intervention, or through a vascular access graft. A description of this type of device is a percutaneously inserted ventricular support device.

There is a need to provide additional improvements in the area of ventricular support devices and similar blood pumps for treating impaired cardiac blood flow.

Summary of the disclosure

The present disclosure relates to intravascular blood pumps and methods of making the same.

One aspect of the present disclosure is an intravascular blood pump comprising a collapsible blood conduit defining an internal lumen for moving blood therethrough, the collapsible blood conduit comprising: a proximal section defined by at least two annular rows of connector elements arranged about a central axis of the collapsible blood conduit; a distal section defined by at least one annular row of connector elements arranged about a central axis of the collapsible blood conduit; a central section axially disposed between the distal section and the proximal section, the central section comprising a plurality of axially extending elongate elements arranged in a helical configuration; and a proximal impeller disposed within at least a portion of the proximal section.

In some embodiments, the proximal, central, and distal stent sections are coupled together (optionally unitary).

In other embodiments, the central section is relatively flexible as compared to the distal and proximal sections such that in response to a lateral force on the blood conduit in the distal impeller section, the blood conduit deforms and assumes a configuration in which the central section has a higher degree of curvature than the proximal and distal sections.

In some examples, the central section includes at least one of a material or a structure such that when a rotational force is applied to the distal end of the blood conduit, the central section is less resistant to collapse than the proximal section and the distal section.

In one embodiment, at least a portion of the proximal and distal sections are free of the helical stent morphology.

In some examples, the axially extending elongate element extends between at least two annular rows of connector elements in the proximal section.

In some embodiments, the distal section is defined by at least two annular rows of connector elements arranged about a central axis of the collapsible blood conduit.

In some embodiments, the axially extending elongate element extends between at least two annular rows of connector elements in the distal section.

In one example, the proximal section is defined by at least four annular rows of connector elements arranged about a central axis of the collapsible blood conduit.

In other examples, the connector elements in each annular row are in a zig-zag configuration.

In some embodiments, the angle between the connector element and the axially extending elongate element ranges from about 10 degrees to 50 degrees.

In some examples, the angle between the connector element and the axially extending elongate element ranges from about 10 degrees to 30 degrees.

In other examples, the angle between the connector element and the axially extending elongate element ranges from about 30 degrees to 50 degrees.

In some embodiments, the axial length of the stent ranges from about 50mm to about 80mm.

In other embodiments, the proximal section has a greater transverse bending stiffness than the distal section.

In some embodiments, the collapsible blood conduit includes a stent configured to transition between a collapsed state and an expanded state, wherein the stent has a diameter in the range of 5.0mm to 10mm in the expanded state and a diameter in the range of 2.5mm to 4.5mm in the collapsed state.

In one embodiment, the pump further comprises a plurality of proximal struts extending proximally from the proximal section.

In some examples, the pump includes a plurality of distal struts extending distally from the distal section.

In other embodiments, the number of the plurality of proximal struts is twice the number of the plurality of distal struts.

In one example, an intravascular blood pump includes ten proximal struts and five distal struts.

In another embodiment, the width of the distal strut is greater than the width of the proximal strut.

In some examples, the axially extending elongate element increases in width near the distal section.

One aspect of the present disclosure is an intravascular blood pump comprising: a collapsible blood conduit having an internal lumen for passage of blood therethrough, the collapsible blood conduit comprising a stent positioned and configured to provide radial support for the blood conduit, the stent comprising a proximal section having a greater radial stiffness than a distal section of the stent; a proximal impeller disposed within at least a portion of the proximal section of the stent; and a distal impeller disposed within at least a portion of the distal section of the stent.

In this aspect, the proximal section may have a greater axial length than the distal section.

In this aspect, the proximal section may comprise a first configuration of structural elements defining a first set of apertures and the distal section may comprise a second configuration of structural elements defining a second set of apertures, wherein the first set of apertures is smaller than the second set of apertures.

In this aspect, the stent may include a central section between the proximal section and the distal section.

In this aspect, the proximal section may have a greater radial stiffness than the central section.

In this aspect, the distal section may have a greater radial stiffness than the central section.

In this aspect, the central section may be configured to flex laterally upon application of a lateral force to the distal section.

In this aspect, the stent may include an elongate element extending axially within the proximal section, the central section, and the distal section.

In this aspect, the portion of the elongate element within the proximal section may be wider than the portion of the elongate element within the central section.

In this aspect, the portion of the elongate element within the distal section may be wider than the portion of the elongate element within the central section.

In this aspect, circumferentially adjacent elongate elements may be connected circumferentially by connector elements within the proximal and distal sections.

In this aspect, the proximal section may include more connector elements than the distal section.

In this aspect, the connector elements may be configured to flex to move the circumferentially adjacent elongate elements closer to one another when the stent transitions from the expanded state to the collapsed state.

In this respect, the elongate elements are not connected to one another within the central section.

In this aspect, the portion of the elongate element within the central section may be arranged in a helical configuration about the central axis of the stent.

In this aspect, the stent may be configured to transition between a collapsed state and an expanded state.

In this aspect, the intravascular blood pump can further include a drive shaft operably coupled to the proximal impeller and the distal impeller, wherein the stent surrounds at least a portion of the drive shaft.

In this aspect, the proximal and distal impellers may be configured to collapse with the collapsible blood conduit.

In this aspect, the stent may comprise an elongate element extending axially along the length of the stent, wherein the axially extending elongate element is connected by one or more annular rows of connector elements within the proximal section.

In this aspect, the elongate elements may be connected by three annular rows of connector elements within the proximal section.

In this aspect, the elongate elements may be connected by four annular rows of connector elements within the proximal section.

In this aspect, the elongate elements may be connected by five annular rows of connector elements within the proximal section.

In this aspect, the connector elements in each annular row may be in a zig-zag configuration.

In this aspect, the stent may comprise an elongate element extending axially along the length of the stent, wherein the axially extending elongate element is connected by a first set of annular row connector elements in the proximal section and a second set of annular row connector elements in the distal section, wherein the first set has a greater number of annular row connector elements than the second set.

In this aspect, the stent may include an elongate member extending axially along the length of the stent and a connector member connecting the elongate member, wherein the angle between the connector member and the elongate member ranges from about 10 degrees to 50 degrees.

In this aspect, the angle between the connector element and the elongate element may be in the range of about 10 degrees to 30 degrees.

In this aspect, the angle between the connector element and the elongate element may be in the range of about 30 degrees to 50 degrees.

In this aspect, the axial length of the stent may be in the range of about 50mm to about 80 mm.

In this aspect, the proximal section may have a greater transverse bending stiffness than the distal section.

In this aspect, the blood conduit may be configured to transition between a collapsed state and an expanded state, wherein the stent has a diameter in the range of 5.0mm to 10mm in the expanded state and a diameter in the range of 2.5mm to 4.5mm in the collapsed state.

One aspect of the present disclosure is a method of using an intravascular blood pump, the method comprising: delivering the intravascular blood pump in the collapsed state toward the heart; a stent that expands an intravascular blood pump in at least a portion of a heart, the expanded stent providing radial support for a blood conduit defining an internal lumen, wherein a proximal section of the stent has a greater radial stiffness than a distal section of the stent; and rotating a proximal impeller disposed within at least a portion of the proximal section of the stent and a distal impeller disposed within at least a portion of the distal section of the stent and pumping blood through the internal lumen of the blood conduit.

In this aspect, the method may further comprise expanding the proximal impeller and the distal impeller within the stent.

In this aspect, the method may further include positioning the intravascular blood pump within at least a portion of the heart such that when the stent expands, a proximal section of the stent provides more radial support for the blood conduit than a distal section of the stent (in some cases, a central section of the stent provides less radial support for the blood conduit than a distal section of the blood conduit).

In this aspect, the stent may comprise a central section between a proximal section and a distal section, the method further comprising positioning the intravascular blood pump within at least a portion of the heart such that lateral forces applied to the stent, optionally to the central portion (and optionally from the native aortic valve leaflet), cause the central portion to flex laterally more than the proximal section and laterally more than the distal section.

In this aspect, the stent may include an elongate element extending axially within the proximal section and the distal section, wherein expanding the stent includes moving the elongate elements radially away from each other.

In this aspect, the method may further comprise collapsing the stent such that the elongate elements move radially inward toward each other.

In this aspect, expanding may include positioning the central stent section at the location of the aortic valve leaflet, positioning at least a portion of the distal section in the left ventricle, and positioning at least a portion of the proximal section in the ascending aorta, wherein the central stent has flexibility such that when positioned at the location of the aortic valve leaflet, the central section assumes a configuration having a higher degree of curvature than the proximal section and the distal section.

In this aspect, the diameter of the stent may be in the range of 5.0mm to 10mm when expanded.

In this aspect, the method may further comprise collapsing the stent to position the stent within the sheath, wherein the stent, when collapsed, ranges from 2.5mm to 4.5mm in diameter.

One aspect of the present disclosure is an intravascular blood pump comprising: a collapsible blood conduit defining an internal lumen for movement of blood therethrough, the collapsible blood conduit comprising a distal impeller section, a proximal impeller section, and a central section axially between the distal impeller section and the proximal impeller section; a proximal impeller disposed within at least a portion of the proximal impeller section; and a distal impeller disposed within at least a portion of the distal impeller section.

In this aspect, the collapsible blood conduit may include a collapsible stent positioned and configured to provide radial support to the blood conduit, the proximal impeller section includes a proximal stent section, the distal impeller section includes a distal stent section, and the central section includes a central stent section.

In this aspect, the proximal, central, and distal stent sections may be coupled together (optionally unitary).

In this aspect, the central section may be relatively flexible as compared to the distal and proximal sections such that in response to a lateral force on the blood conduit in the distal impeller section, the blood conduit deforms and assumes a configuration in which the central section has a higher degree of curvature than the proximal and distal sections.

In this aspect, the central section may comprise at least one of a material or a structure such that when a rotational force is applied to the distal end of the blood conduit, the central section is less resistant to collapse than the proximal section and the distal section.

In this aspect, the central section may comprise a helical stent morphology, wherein the helical stent morphology, wherein at least a portion of the proximal section and the distal section are devoid of the helical stent morphology.

In this aspect, the axial length of the stent ranges from about 50mm to about 80mm.

In this aspect, the proximal impeller section may have a greater transverse bending stiffness than the distal impeller section.

In this aspect, the collapsible blood conduit may include a stent configured to transition between a collapsed state and an expanded state, wherein the stent has a diameter in the range of 5.0mm to 10mm in the expanded state and a diameter in the range of 2.5mm to 4.5mm in the collapsed state.

One aspect of the present disclosure is an intravascular blood pump comprising: a collapsible blood conduit defining an internal lumen for movement of blood therethrough, the collapsible blood conduit comprising a collapsible stent; a plurality of struts (e.g., 2951, 2952) extending from the blood tubing, the plurality of struts disposed at the pump inflow or pump outflow; one or more impellers (optionally distal and proximal impellers) disposed at least partially within the blood conduit.

In this aspect, the plurality of struts may include a plurality of outflow struts, wherein a first one of the plurality of outflow struts has a different configuration than at least one other outflow strut.

In this aspect, the first struts may have a proximal region having a configuration different from the proximal region of the at least one other outflow strut.

In this aspect, the proximal region may be a non-expandable and collapsible region of the strut (optionally coupled to the central hub), wherein a region of the first strut distal from the proximal region is coupled to the blood conduit (optionally unitary) and is expandable and collapsible.

In this aspect, the proximal region may have a width that is less than the width of at least one other outflow strut at the same axial location.

In this aspect, the width of the second outflow strut at the axial position may be smaller than the width of at least one other outflow strut at the axial position (optionally the same as the width of the first strut).

In this aspect, the width of the circumferentially adjacent first and second outflow struts at the axial position may be less than the width of at least one other outflow strut at the axial position.

In this aspect, the circumferentially adjacent first and second outflow struts may each have a sensor housing recess formed therein at an axial position, wherein the recesses circumferentially face each other.

In this aspect, the plurality of struts may include a plurality of inflow struts, wherein at least one inflow strut has a different configuration than at least one other inflow strut.

In this regard, the different configurations may be any of the differences described or claimed herein (e.g., smaller width of distal non-expandable region, circumferential recess, etc.).

In this aspect, the first outflow strut has a different configuration than the at least one other outflow strut, and wherein the first inflow strut has a different configuration than the at least one other inflow strut.

In this aspect, the first outflow and the first inflow strut may be circumferentially offset.

In this aspect, the first outflow and first inflow struts may be circumferentially aligned (e.g., as shown by the "middle" struts in fig. 29A).

In this aspect, the first outflow strut and the second outflow strut may each have a configuration (optionally to accommodate outflow pressure sensor housing) that is different from at least the other outflow struts and optionally at their proximal non-expandable regions.

In this aspect, the first inflow strut and the second inflow strut may each have a configuration that is different from at least the other inflow struts (optionally to accommodate inflow of the pressure sensor housing) and optionally at a distal non-expandable region thereof.

In this aspect, at least one of the first inflow leg and the second inflow leg may be circumferentially offset from at least one of the outflow legs.

In this aspect, at least one of the plurality of struts may include a pressure sensor pocket formed therein that is sized and positioned relative to the pressure sensor and/or the pressure sensor housing to accommodate the presence of the pressure sensor and/or the pressure sensor housing.

In this aspect, the pressure sensor pocket may include an area of relatively small width.

In this aspect, the plurality of struts may have an axially extending configuration.

In this aspect, the connector elements in each annular row may be arranged in a zig-zag configuration.

In this aspect, the collapsible stent may include a proximal section having a greater lateral bending stiffness than a distal section of the collapsible stent.

In this aspect, the stent may be configured to transition between a collapsed state and an expanded state, wherein the stent has a diameter in the range of 5.0mm to 10mm in the expanded state and a diameter in the range of 2.5mm to 4.5mm in the collapsed state.

One aspect of the present disclosure is an intravascular blood pump comprising: a collapsible blood conduit having an internal lumen for blood to pass therethrough, the collapsible blood conduit comprising a stent positioned and configured to provide radial support for the blood conduit, the stent comprising a proximal section, a central section, and a distal section, the central section being disposed between the proximal section and the distal section and being more flexible than the distal section and the proximal section; a proximal impeller disposed within at least a portion of the proximal section of the stent; and a distal impeller disposed within at least a portion of the distal section of the stent, wherein the central section is flexible such that the central section assumes a curved configuration when the blood conduit is positioned across the aortic valve, wherein the central section is disposed at the location of the aortic valve leaflets, the curved configuration such that the axis of rotation of the proximal impeller is not aligned with the axis of rotation of the distal impeller.

In this aspect, the central section may comprise a plurality of helical portions, optionally circumferentially separated from one another by a scaffold.

In this aspect, the proximal, central, and distal sections may have different radial stiffness.

In this aspect, the proximal section may have a greater radial and lateral bending stiffness than the distal section.

One aspect of the present disclosure is a tubular stent for an intravascular blood pump, the tubular stent comprising: a first impeller section configured to house a first impeller; a second impeller section configured to house a second impeller; and a central section between the first impeller section and the second impeller section, the central section having a plurality of elongate elements extending axially in a helical arrangement and being unconnected to each other within the central section, wherein the helical arrangement of elongate elements is configured to laterally bend the central section upon application of a lateral force applied to the tubular stent.

In this aspect, the first impeller section and the second impeller section may comprise connector elements connecting the elongate elements within the first impeller section and the second impeller section.

In this aspect, the elongate member may be parallel to the central axis of the tubular support within the first impeller section.

In this aspect, the elongate member may be parallel to the central axis of the tubular support within the second impeller section.

In this aspect, the central section may have greater lateral flexibility than the first impeller section or the second impeller section.

In this aspect, the first impeller section and the second impeller section may each have a greater radial stiffness than the central section.

In this aspect, the tubular stent may include a plurality of struts that curve radially inward and are configured to connect to a central hub of an intravascular blood pump.

In this aspect, the tubular stent may be configured to transition between a radially expanded state and a radially collapsed state.

In this aspect, the center section may have a greater axial length than each of the first and second impeller sections.

In this aspect, the elongate elements may be connected by one or more annular rows of connector elements within the first impeller section.

In this respect, the elongate elements may be connected by three annular rows of connector elements within the first impeller section.

In this aspect, the elongate members may be connected by four annular rows of connector members within the first impeller portion.

In this aspect, the elongate members may be connected by five annular rows of connector members within the first impeller portion.

In this aspect, the tubular stent may further comprise a membrane covering at least a portion of the inner surface and/or the outer surface of the tubular stent.

In this aspect, the elongate element may extend axially through the first impeller section, the central section and the second impeller section.

In this regard, laterally bending the central section may cause the first impeller section to be axially misaligned relative to the second impeller section.

In this aspect, the first impeller section may have a greater radial and transverse bending stiffness than the second impeller section.

In this aspect, the tubular stent may be configured to transition between a collapsed state and an expanded state, wherein the tubular stent has a diameter in the range of 5.0mm to 10mm in the expanded state and a diameter in the range of 2.5mm to 4.5mm in the collapsed state.

One aspect of the present disclosure is an intravascular blood pump comprising: a tubular stent, the tubular stent comprising: a proximal section at least partially surrounding the proximal impeller; a distal section at least partially surrounding the distal impeller; and a central section between the proximal end and the distal section, the central section having a plurality of elongate elements extending axially in a helical arrangement and being unconnected to each other within the central section.

In this aspect, the helical arrangement may provide sufficient lateral flexibility to allow the central section to deflect when a lateral force is applied to the tubular stent.

In this regard, deflection of the central section may result in axial misalignment of the proximal section relative to the distal section.

In this aspect, the central section may be configured to return to the original shape after the lateral force is released from the tubular stent.

In this aspect, the proximal section may be axially aligned relative to the distal section when the stent returns to the original shape.

In this aspect, each of the proximal and distal sections may include a plurality of struts coupled to a central hub of the intravascular blood pump.

In this aspect, the tubular stent may surround at least a portion of the central drive shaft.

In this aspect, the drive shaft may be configured to flex laterally as the tubular stent flexes laterally.

One aspect of the present disclosure is a tubular stent for an intravascular blood pump, the tubular stent comprising: a first impeller section configured to at least partially house a first impeller, the first impeller section having a first cradle morphology; and a second impeller section configured to at least partially house a second impeller, the second impeller section having a second cradle morphology, wherein the first cradle morphology is more closely arranged than the second cradle morphology.

In this aspect, the first scaffold morphology may be associated with a first stiffness and the second scaffold morphology is associated with a second stiffness, wherein the first stiffness is greater than the second stiffness.

In this aspect, the first stiffness and the second stiffness may include one or more of a radial stiffness and a bending stiffness.

In this aspect, the tubular stent may further comprise a central section between the first impeller section and the second impeller section, the central section having a stent morphology that is more loosely arranged than each of the first impeller section and the second impeller section.

In this aspect, the central section may comprise a plurality of elongate elements extending axially in a helical arrangement and disconnected from each other within the central section, wherein the helical arrangement of elongate elements is configured to laterally bend the central section upon application of a lateral force applied to the tubular stent.

In this aspect, the first impeller section may be a proximal section and the second impeller section is a distal section.

These and other aspects are described herein.

Drawings

Fig. 1 is a side view of an exemplary expandable pump section including an expandable impeller housing including a stent and a blood conduit, and a plurality of impellers.

Fig. 2 is a side view of an exemplary expandable pump portion including an expandable impeller housing, a blood conduit, a plurality of impellers, and a plurality of expandable stent sections or support members.

Fig. 3A, 3B, 3C and 3D illustrate an exemplary expandable pump portion including a blood conduit, a plurality of impellers, and a plurality of expandable stent sections or support members.

Fig. 4 illustrates an exemplary target location for an expandable pump section including a blood conduit, a plurality of expandable stent sections or support members, and a plurality of impellers.

Fig. 5 illustrates an exemplary pump section including an expandable impeller housing, a blood conduit, and a plurality of impellers.

Fig. 6A illustrates at least a portion of an exemplary catheter blood pump including a pump portion in which at least two different impellers may rotate at different speeds.

Fig. 6B illustrates at least a portion of an exemplary catheter blood pump including a pump portion in which at least two different impellers may rotate at different speeds.

Fig. 6C illustrates at least a portion of an exemplary catheter blood pump including a pump portion having at least two impellers with different pitches.

Fig. 7 illustrates a portion of an exemplary catheter blood pump including a pump portion.

FIG. 8 illustrates an exemplary expandable pump section including a plurality of expandable impellers including one or more bends formed therein between adjacent impellers.

Fig. 9 illustrates an exemplary expandable pump section including multiple impellers and blood tubing.

FIG. 10 illustrates an exemplary stent design and an exemplary strut.

FIG. 11 illustrates an exemplary stent design and an exemplary strut.

Fig. 12A-12F illustrate exemplary sequences of steps that may be performed to deploy an exemplary pump portion of a catheter blood pump.

Fig. 13A and 13B illustrate exemplary portions of an expandable pump section.

Fig. 13C shows the stent from fig. 13A and 13B shown in a flattened and unexpanded configuration, with optional distal and proximal struts extending axially therefrom.

Fig. 14A illustrates an exemplary expandable stent, which may be part of any of the expandable pump sections herein.

Fig. 14B shows the stent and struts from fig. 14A in a flattened and unexpanded configuration.

Fig. 15A illustrates an exemplary expandable stent, which may be part of any of the expandable pump sections herein.

Fig. 15B shows the stent and struts from fig. 15A in a flattened and unexpanded configuration.

FIG. 16 illustrates an exemplary stent and optionally coupled struts in a flattened and unexpanded configuration.

FIG. 17 illustrates an exemplary stent and optionally coupled struts in a flattened and unexpanded configuration.

Fig. 18A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 18B shows the stent from fig. 18A in an expanded configuration.

Fig. 19A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 19B shows the stent from fig. 19A in an expanded configuration.

FIG. 20A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 20B shows the stent from fig. 20A in an expanded configuration.

FIG. 21A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 21B shows the stent from fig. 21A in an expanded configuration.

FIG. 22A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 22B shows the stent from fig. 22A in an expanded configuration.

FIG. 23A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 23B shows the stent from fig. 23A in an expanded configuration.

FIG. 24A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 24B shows the stent from fig. 24A in an expanded configuration.

Fig. 25A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 25B shows the stent from fig. 25A in a flattened expanded configuration.

Fig. 26A shows an exemplary stent in a flattened and unexpanded configuration.

Fig. 26B illustrates an exemplary section of the stent shown in fig. 26A.

FIG. 27A illustrates an exemplary stent in a flattened and unexpanded configuration.

Fig. 27B shows the stent from the non-collapsed configuration of fig. 27A.

Fig. 28A and 28B illustrate an exemplary collapsible pump portion that includes a central stent section that is not unitary and that is not coupled to one or more axially adjacent stent sections.

Fig. 29A-29E illustrate exemplary stents having sections of different stiffness: FIG. 29A shows a flattened view of the stent; FIG. 29B shows a blood conduit with a stent having a membrane in an expanded configuration; fig. 29C shows the proximal impeller region of the blood tubing (including stent and membrane) in a collapsed configuration within the sheath; FIG. 29D shows a close-up view of the proximal portion of the stent; and fig. 29E shows a close-up view of the distal portion of the stent.

Fig. 30 illustrates a flattened view of another exemplary stent having a different stent morphology.

Fig. 31 shows a flattened view of another exemplary stent having a different stent morphology.

Fig. 32A and 32B illustrate another exemplary stent having a different stent morphology: FIG. 32A shows a flattened view of the stent; fig. 32B shows the stent in an expanded state.

Fig. 33A-33B illustrate another exemplary stent in flattened and expanded states, respectively.

Fig. 34 illustrates another exemplary stent in a flattened view.

Detailed Description

The present disclosure relates to medical devices, systems, and methods of use and manufacture. The medical devices herein may include a distal pump portion (which may also be referred to herein as a working portion) adapted to be disposed within a physiological vessel, wherein the distal pump portion includes one or more components that act on a fluid. For example, the pump portion herein may include one or more rotating members that, when rotated, may facilitate movement of a fluid (such as blood).

Any disclosure herein relating to an aspect of a system, apparatus, or method of use may be combined with any other suitable disclosure herein. For example, figures depicting only one aspect of an apparatus or method may be included with other embodiments even if not specifically stated in the description of one or both portions of the present disclosure. Thus, it should be understood that combinations of the different portions of the present disclosure are included herein.

Fig. 1 is a side view illustrating a distal portion of an exemplary catheter blood pump, the catheter blood pump comprising a pump portion 1600, wherein the pump portion 1600 comprises a proximal impeller 1606 and a distal impeller 1616, both of the proximal impeller 1606 and the distal impeller 1616 being in operable communication with a drive cable 1612 (also referred to as a drive shaft). In fig. 1, pump portion 1600 is in an expanded configuration, but is adapted to collapse into a delivery configuration such that pump portion 1600 may be delivered in a lower profile. The impeller may be attached to a drive mechanism 1612 (e.g., a drive cable). The drive mechanism 1612 is in operative communication with an external motor (not shown) and extends through the elongate shaft 1610. The phrases "pump portion" and "working portion" (or derivatives thereof) may be used interchangeably herein unless otherwise indicated. For example, but not limited to, "pump portion" 1600 may also be referred to herein as a "working portion". Although the embodiment of fig. 1 shows two impellers (i.e., a distal impeller and a proximal impeller), it should be understood that the embodiment of fig. 1 or any other embodiment in the present disclosure may include only a single impeller, such as only a proximal impeller or only a distal impeller.

The pump portion 1600 also includes an expandable member or stent 1602, which expandable member or stent 1602 in this embodiment has a proximal end 1620 that extends further proximally than the proximal end of the proximal impeller 1606 and a distal end 1608 that extends further distally than the distal end 1614 of the distal impeller 1616. The expandable member may also be referred to herein as an expandable stent or stent section. The expandable stent 1602 is disposed radially outward of the impeller along the axial length of the impeller. The expandable stent 1602 may be constructed in a manner similar to and made of materials similar to many types of expandable structures known in the medical arts that are capable of collapsing and expanding, examples of which are provided herein. Examples of suitable materials include, but are not limited to, polyurethane elastomers, metal alloys, and the like.

The pump portion 1600 also includes a blood conduit 1604 coupled to the expandable member 1602 and supported by the expandable member 1602, having a length L, and extending axially between the impellers. A conduit 1604 creates and provides a fluid lumen between the two impellers. When in use, fluid moves through the lumen defined by the conduit 1604. The conduits herein may be impermeable, or the conduits may be semi-permeable, or even porous, so long as they still define an inner lumen. The tubing herein is also flexible unless otherwise indicated. The tubing here extends completely (i.e. 360 degrees) around at least a part of the pump section. In the pump portion 1600, the tubing extends completely around the expandable member 1602, but not all the way to either the proximal end 1602 or the distal end 1608 of the expandable member 1602. The configuration of the expandable member creates at least one inlet aperture to allow inflow "I" and at least one outflow aperture to allow outflow "O". The tubing 1604 improves impeller pumping dynamics compared to a pump section without tubing. As described herein, an expandable member or stent may also be generally considered as part of a blood conduit that together define a blood lumen. In these cases, the stent and the material supported by the stent may be referred to herein as an expandable impeller housing or housing.

The expandable member 1602 may have a variety of structures and be made of a variety of materials. For example, the expandable member 1602 may be formed similar to an expandable scaffold or a scaffold-like device or any other example provided herein. For example, but not limiting of, the expandable member 1602 may have an open weave structure, such as a 24-end weave, however, more or fewer weave lines may be used. Exemplary materials for the expandable member and struts herein include nitinol, cobalt alloys, and polymers, although other materials may also be used. As shown, the expandable member 1602 has an expanded configuration in which an outer dimension of the expandable member (measured orthogonally relative to the longitudinal axis of the working portion) is greater at least in a region thereof radially disposed outside of the impellers than in a central region 1622 of the expandable member extending axially between the impellers. In this embodiment, the drive mechanism 1612 is coaxial with the longitudinal axis. In use, the central region may be placed across a valve (e.g., an aortic valve). In some embodiments, the expandable member 1602 is adapted and configured to expand to an outermost dimension of 12-24F (4.0-8.0 mm) with the impeller axially within the expandable member, and to an outermost dimension of 10-20F (3.3-6.7 mm) in a central region 1622 between the impellers. The smaller outer dimension of the central region may reduce the forces acting on the valve, which may reduce or minimize damage to the valve. The larger size of the expandable member in the impeller region may help to axially stabilize the working portion in use. The expandable member 1602 has a generally dumbbell configuration. The expandable member 1602 has an outer configuration that tapers as the expandable member 1602 transitions from the impeller region to the central region 1622 and again tapers at the distal and proximal ends of the expandable member 1602.

The expandable member 1602 has a proximal end 1620 coupled to the shaft 1610 and a distal end 1608 coupled to a distal tip 1624. The impeller and drive mechanism 1612 rotates within the expandable member and tubing assembly. The drive mechanism 1612 is axially stable relative to the distal tip 1624, but is free to rotate relative to the tip 1624.

In some embodiments, the expandable member 1602 may collapse by pulling tension on the expandable member from end to end. This may include linear movement (e.g., without limitation, a 5-20mm stroke) to axially extend the expandable member 1602 to a collapsed configuration having a collapsed outer dimension. The expandable member 1602 may also be collapsed by pushing an outer shaft (such as a sheath) onto the expandable member/tubing assembly, collapsing the expandable member and tubing toward their collapsed delivery configuration.

Impellers 1606 and 1616 are also adapted and configured such that one or more blades will stretch or radially compress to a reduced outermost dimension (measured perpendicular to the longitudinal axis of the working portion). For example, and without limitation, any impeller herein may include one or more blades made from a plastic formulation having spring characteristics, such as any impeller described in U.S. patent No. 7,393,181, the disclosure of which is incorporated herein by reference for all purposes and may be incorporated into embodiments herein unless otherwise indicated by the present disclosure. Alternatively, for example, one or more collapsible impellers may comprise a super-elastic wire frame having a polymer or other material used as a webbing through the wire frame, such as those described in U.S. patent No. 6,533,716, the disclosure of which is incorporated herein by reference for all purposes.

The inflow and/or outflow configuration of working portion 1600 may be primarily axial in nature.

Exemplary unsheathing and unsheathing techniques and concepts for collapsing and expanding medical devices are known, such as those described and illustrated in U.S. patent No. 7,841,976 or U.S. patent No. 8,052,749, the disclosures of which are incorporated herein by reference.

Fig. 2 is a side view illustrating a deployed configuration (shown outside the body) of a distal portion of an exemplary embodiment of a catheter blood pump. Exemplary blood pump 1100 includes a working portion 1104 (working portion 1104 may also be referred to herein as a pump portion as described herein) and an elongate portion 1106 extending from working portion 1104. The elongate portion 1106 may extend to a more proximal region of the system (not shown for clarity) and the more proximal region may include, for example, a motor. Working portion 1104 includes a first expandable stent or member 1108 and a second expandable stent or member 1110 axially spaced apart along a longitudinal axis LA of working portion 1104. The first and second brackets 1108, 1110 (as well as any other individual brackets herein) may also be referred to as part of a common bracket and as bracket segments herein. In this case, axially spaced refers to the entire first expandable member being axially spaced from the entire second expandable member along the longitudinal axis LA of the working portion 1104. The first end 1122 of the first expandable member 1108 is axially spaced from the first end 1124 of the second expandable member 1110.

The first expandable member 1108 and the second expandable member 1110 each generally include a plurality of elongated segments disposed relative to one another to define a plurality of apertures 1130, wherein only one aperture is marked in the second expandable member 1110. The expandable member may have a variety of configurations and may be configured in a variety of ways, such as, but not limited to, any configuration or structure in U.S. patent No. 7,841,976 or a tube in No. 6,533,716, which are described as self-expanding metal endoprosthesis materials. For example, and without limitation, one or both of the expandable members may have a braided structure or may be at least partially formed by laser cutting a tubular element.

Working portion 1104 further includes a blood conduit 1112, blood conduit 1112 coupled to first expandable member 1108 and second expandable member 1110 and extending axially between first expandable member 1108 and second expandable member 1110 in the deployed configuration. The central region 1113 of the conduit 1112 spans an axial distance 1132 where the working portion is devoid of the first and second expandable members 1108, 1110. The central region 1113 may be considered to be axially located between the expandable members. The distal end 1126 of the conduit 1112 does not extend as far distally as the distal end 1125 of the second expandable member 1110, and the proximal end of the conduit 1128 does not extend as far proximally as the proximal end 1121 of the first expandable member 1108.

When the disclosure herein relates to a blood conduit coupled to an expandable stent or member, the term "coupled" herein does not require that the conduit be directly attached to the expandable member such that the conduit physically contacts the expandable member. However, even without direct attachment, the term "coupled" herein refers to the conduit and the expandable member being joined together such that when the expandable member expands or collapses, the conduit begins to transition to a different configuration and/or size. Thus, "coupled" herein refers to the conduit that will move as the expandable member to which it is coupled transitions between the expanded and collapsed configurations.

Any of the blood tubing herein may be deformable to some extent. For example, conduit 1112 includes an elongate member 1120, which elongate member 1120 may be made of one or more materials that allow a central region 1113 of the conduit to deform radially inward (toward LA) to some extent in response to forces from valve tissue (e.g., leaflets) or a replacement valve, such as when working portion 1104 is deployed toward the configuration shown in fig. 2, in use. In some embodiments, the tubing may be tightly stretched between the expandable members. Alternatively, the tubing may be designed with a relaxation that causes a greater degree of compliance. This may be desirable when the working portion is disposed on a fragile structure (such as an aortic valve), which may allow the valve to compress the tubing in a manner that minimizes point stresses in the valve. In some embodiments, the tubing may include a membrane attached to the proximal and distal expandable members. Exemplary materials that can be used for any of the conduits herein include, but are not limited to, polyurethane rubber, silicone rubber, acrylic rubber, expanded polytetrafluoroethylene, polyethylene terephthalate, including any combination thereof.

Any of the conduits herein may have a thickness of, for example, 0.5-20 thousandths of an inch (thou), such as 1-15 thousandths of an inch, or 1.5-15 thousandths of an inch, 1.5-10 thousandths of an inch, or 2-10 thousandths of an inch.

Any blood tubing or at least a portion of tubing herein may be impermeable to blood. In fig. 2, working portion 1104 includes a lumen extending from a distal end 1126 of conduit 1112 and extending to a proximal end 1128 of conduit 1112. The lumen is defined by the conduit 1112 in the central region 1113, but may be considered to be defined by both the conduit and the portion of the expandable member in the region axially adjacent the central region 1113. However, in this embodiment, it is the tubing material that causes the lumen to exist and prevents blood from passing through the tubing.

Unless otherwise indicated, any tubing secured to one or more expandable members herein may be secured such that the tubing is disposed radially outward of the one or more expandable members, radially inward of the one or more expandable members, or both radially outward of the one or more expandable members and radially inward of the one or more expandable members, and the expandable members may be impregnated with tubing material.

The proximal and distal expandable stents or members help to maintain the blood conduit in an open configuration to form a lumen, while each also forms a working environment for the impeller, as described below. When in the deployed configuration, each expandable stent is maintained in a spaced relationship relative to the corresponding impeller, which allows the impeller to rotate within the expandable member without contacting the expandable member. Working portion 1104 includes a first impeller 1116 and a second impeller 1118, with first impeller 1116 being radially disposed within first expandable member 1108 and second impeller 1118 being radially disposed within second expandable member 1110. In this embodiment, even though the two impellers are different and separate impellers, the two impellers are in operative communication with a common drive mechanism (e.g., drive cable 1117) such that when the drive mechanism is activated, the two impellers rotate together. In this deployed configuration, the impellers 1116 and 1118 are axially spaced apart along the longitudinal axis LA just as the expandable members 1108 and 1110 are axially spaced apart. Although the embodiment of fig. 2 shows two impellers (i.e., a distal impeller and a proximal impeller), it should be understood that the embodiment of fig. 2 or any other embodiment in the present disclosure may include only a single impeller, such as only a proximal impeller or only a distal impeller.

Impellers 1116 and 1118 are also axially located within the ends of expandable members 1108 and 1110, respectively (except radially located within expandable members 1108 and 1110). Even if the expandable member includes struts (e.g., tapered struts in side view) extending from a central region of the expandable member toward a longitudinal axis of the working portion, the impeller herein may be considered to be axially located within the expandable member. In fig. 2, the second expandable member 1110 extends from a first end 1124 (proximal end) to a second end 1125 (distal end).

In fig. 2, the distal portion of the impeller 1118 extends distally beyond the distal end 1126 of the tube 1112 and the proximal portion of the impeller 1116 extends proximally beyond the proximal end 1128 of the tube 1112. In this figure, the portion of each impeller is axially located within the duct in this deployed configuration.

In the exemplary embodiment shown in FIG. 2, the impellers 1116 and 1118 are in operative communication with a common drive mechanism 1117, and in this embodiment, the impellers are each coupled to the drive mechanism 1117, with the drive mechanism 1117 extending through the shaft 1119 and the working portion 1104. The drive mechanism 1117 may be, for example, an elongated drive cable that, when rotated, causes the impeller to rotate. In this example, as shown, the drive mechanism 1117 extends to the distal tip 1114 and is axially fixed relative to the distal tip 1114, however the drive mechanism 1117 is adapted to rotate relative to the distal tip 1114 when actuated. Thus, in this embodiment, when the drive mechanism rotates, the impeller and the drive mechanism 1117 rotate together. Any number of known mechanisms may be used for the rotary drive mechanism, such as using a motor (e.g., an external motor) to rotate the drive mechanism.

The expandable member and the conduit are not in rotational operative communication with the impeller and the drive mechanism. In this embodiment, the proximal end 1121 of the proximal expandable member 1108 is coupled to a shaft 1119, which 1119 may be a shaft of the elongate portion 1106 (e.g., an outer catheter shaft). The distal end 1122 of the proximal expandable member 1108 is coupled to the central tubular member 1133, and the drive mechanism 1117 extends through the central tubular member 1133. A central tubular member 1133 extends distally from the proximal expandable member 1108 within the conduit 1112 and is also coupled to the proximal end 1124 of the distal expandable member 1110. The drive mechanism 1117 is thus within the central tubular member 1133 and rotates relative to the central tubular member 1133. A central tubular member 1133 extends axially from the proximal expandable member 1108 to the distal expandable member 1110. As shown, a distal end 1125 of the distal expandable member 1110 is coupled to the distal tip 1114. The drive mechanism 1117 is adapted to rotate relative to the end 1114, but is axially fixed relative to the end 1114.

Working portion 1104 is adapted and configured to collapse to a smaller profile than its deployed configuration (which is shown in fig. 2). This allows working portion 1104 to be delivered using a lower profile delivery device (smaller F-number) than would be required if working portion 1104 were non-collapsible. Even though not specifically illustrated herein, any expandable member and impeller may be adapted and configured to collapse to some extent into a smaller delivery configuration.

The working portion herein may be collapsed into a collapsed delivery configuration using conventional techniques, such as having an outer sheath that is movable relative to the working portion (e.g., by axially moving one or both of the sheath and the working portion). For example, and without limitation, any of the systems, devices, or methods shown in the following references may be used to facilitate the collapse of the working portion herein: U.S. patent No. 7,841,976 or U.S. patent No. 8,052,749, the disclosures of which are incorporated herein by reference for all purposes.

Fig. 3A-3D illustrate an exemplary pump section that is similar in some respects to the pump section shown in fig. 2. Pump portion 340 is similar to pump portion 1104 in that pump portion 340 includes two expandable members axially spaced apart from each other when the pump portion expands, and a conduit extending between the two expandable members. Fig. 3A is a perspective view, fig. 3B is a side view, and fig. 3C and 3D are close-up side cross-sectional views of portions of the view in fig. 3B.

The pump portion 340 includes a proximal impeller 341 and a distal impeller 342, the proximal impeller 341 and the distal impeller 342 being coupled to and in operative communication with a drive cable, the drive cable defining an interior cavity therein. The lumen may be sized to accommodate a guidewire that may be used to deliver the working portion to a desired location. In this embodiment, the drive cable includes a first section 362 (e.g., a wound material), a second section 348 (e.g., a tubular member) coupled with the proximal impeller 341, a third section 360 (e.g., a wound material), and a fourth section 365 (e.g., a tubular material) coupled with the distal impeller 342. The drive cable sections all have the same inner diameter such that the inner lumen has a constant inner diameter. The drive cable sections may be secured to each other using known attachment techniques. The distal end of the fourth section 365 extends to a distal region of the working portion to allow the working portion to be advanced, for example, over a guide wire for positioning the working portion. In this embodiment, the second section and the fourth section may be stiffer than the first section and the third section. For example, the second and fourth sections may be tubular and the first and third sections may be of wound material to impart less rigidity.

The pump portion 340 includes a proximal expandable stent 343 and a distal expandable stent 344, each of the proximal expandable stent 343 and the distal expandable stent 344 extending radially outward of one of the impellers. The expandable stent has a distal end and a proximal end that also extend axially beyond the distal end and proximal end of the impeller, as can be seen in fig. 3B-3D. Coupled to the two expandable stents are blood tubing 356, the blood tubing 356 having a proximal end 353 and a distal end 352. The two expandable stents each include a plurality of proximal struts and a plurality of distal struts. The proximal struts in the proximal expandable stent 343 extend to the shaft section 345 and are fixed to the shaft section 345, the shaft section 345 is coupled to the bearing 361, and the drive cable extends through the bearing 361 and is configured and dimensioned for rotation. The distal struts of the proximal expandable stent 343 extend to and are secured to a proximal region (in this case, the proximal end) of a central tubular member 346, which central tubular member 346 is axially disposed between the expandable members. The proximal end of the central tubular member 346 is coupled to a bearing 349, as shown in fig. 3C, with the drive cable extending through the bearing 349 and rotating therein. The proximal struts extend axially from the distal expandable stent 344 to and are secured to a distal region (in this case, the distal end) of the central tubular member 346. A bearing 350 is also coupled to a distal region of the central tubular member 346, as shown in fig. 3D. The drive cable extends through the bearing 350 and rotates relative to the bearing 350. The distal struts extending from the distal expandable stent extend to shaft section 347 and are secured to shaft section 347 (see fig. 3A), shaft section 347 may be considered part of the distal tip. The shaft section 347 is coupled to a bearing 351 (see fig. 3D), and the drive cable extends through the bearing 351 and rotates relative to the bearing 351. The distal tip also includes a bearing 366 (see fig. 3D), which bearing 366 may be a thrust bearing. Working portion 340 may be similar or identical in some respects to working portion 1104, even though not explicitly included in the description. In this embodiment, unlike working portion 1104, conduit 356 extends at least as far as the end of the impeller. Either embodiment may be modified such that the conduit extends to the position described in the other embodiment. In some embodiments, the section 360 may be a tubular section, rather than a wound section.

In alternative embodiments, at least a portion of any of the impellers herein may extend outside of the fluid lumen. For example, only a portion of the impeller may extend beyond the end of the fluid lumen in the proximal or distal direction. In some embodiments, the portion of the impeller that extends outside of the fluid lumen is a proximal portion of the impeller and includes a proximal end (see, e.g., proximal impeller in fig. 2). In some embodiments, the portion of the impeller that extends outside the fluid lumen is a distal portion of the impeller and includes a distal end (see, e.g., distal impeller in fig. 2). When the disclosure herein refers to an impeller extending outside (or beyond the end) of the fluid lumen, it is meant to refer to the relative axial positions of these components, which is most easily seen in side or top view, for example in fig. 2.

However, the second impeller at the other end of the fluid chamber cannot extend beyond the fluid chamber. For example, an illustrative alternative design may include a proximal impeller that extends proximally beyond the proximal end of the fluid lumen (as in fig. 2), and the fluid lumen does not extend distally beyond the distal end of the distal impeller (as in fig. 3B). Alternatively, the distal end of the distal impeller may extend distally beyond the distal end of the fluid lumen, but the proximal end of the proximal impeller does not extend proximally beyond the proximal end of the fluid lumen. In any of the pump sections herein, none of the impellers may extend beyond the end of the fluid lumen. Although the embodiments of fig. 3A-3D show two impellers (i.e., a distal impeller and a proximal impeller), it should be understood that this or any other embodiment in the present disclosure may include only a single impeller, such as only a proximal impeller or only a distal impeller.

Although specific exemplary locations may be shown herein, the fluid pump may be capable of use in a variety of locations within the body. Some exemplary locations for placement include placement near an aortic or pulmonary valve, e.g., across the valve and on one or both sides of the valve, and in the case of an aortic valve, optionally including portions in the ascending aorta. In some other embodiments, for example, in use, the pump may be located further downstream, for example, disposed in the descending aorta.

Fig. 4 illustrates an exemplary placement of the pump portion 1104 from the catheter blood pump 1000 of fig. 2. One difference shown in fig. 4 is that the conduit extends at least as far as the end of the impeller, as in fig. 3A-3D. Fig. 4 shows the pump portion 1104 in a deployed configuration, with the pump portion 1104 positioned in place through the aortic valve. The pump portion 1104 may be delivered as shown via, for example, but not limited to, femoral artery access (a known access procedure). Although not shown for clarity, system 1000 may also include an outer sheath or shaft in which working portion 1104 is disposed during delivery to a location near the aortic valve. The sheath or shaft may be moved proximally (toward the ascending aorta "AA" and away from the left ventricle "LV") to allow deployment and expansion of the working portion 1104. For example, the sheath may be withdrawn to allow the second expandable stent 1110 to expand, with continued proximal movement allowing the first expandable stent 1108 to expand.

In this embodiment, the second expandable stent 1110 has been expanded and positioned in the expanded configuration such that the distal end 1125 is located in the left ventricle "LV" and away from the aortic valve leaflet "VL" and away from the annulus. The proximal end 1124 is also positioned away from the leaflet VL, but in some approaches the proximal end 1124 may extend slightly axially within the leaflet VL. This embodiment is an example of a method in which at least half of the second expandable member 1110 is within the left ventricle, as measured along its length (measured along the longitudinal axis). And as shown, this is also an example of a method in which the entire second expandable member 1110 is located within the left ventricle. This is also an example of a method in which at least half of the second impeller 1118 is located in the left ventricle, and is also an embodiment in which the entire second impeller 1118 is located in the left ventricle.

Continued retraction of the outer shaft or sheath (and/or distal movement of the working end 1104 relative to the outer sheath or shaft) continues to release the conduit 1112 until the central region 1113 is released and deployed. The expansion of the expandable stents 1108 and 1110 results in the blood conduit 1112 assuming a more open configuration, as shown in fig. 4. Thus, while in this embodiment the tube 1112 does not have the same self-expanding characteristics as an expandable stent, when the working end is deployed, the tube will assume a deployed, more open configuration. At least a portion of the central region 1113 of the conduit 1112 is located in the aortic valve engagement region and engages the leaflets. In fig. 3A-3D, there is a central region 1113 that extends distally beyond the short length of leaflet VL, but at least some portions of central region 1113 are axially within the leaflet.

Continued retraction of the outer shaft or sheath (and/or distal movement of the working end 1104 relative to the outer sheath or shaft) deploys the first expandable member 1108. In this embodiment, the first expandable stent 1108 has been expanded and positioned (as shown) in the expanded configuration such that the proximal end 1121 is located in the ascending aorta AA and is proximal to the leaflets "VL". The distal end 1122 is also positioned proximate to the leaflet VL, but in some approaches the distal end 1122 may extend slightly axially within the leaflet VL. This embodiment is an example of a method in which at least half of the first expandable member 1110 is within the ascending aorta, as measured along its length (measured along the longitudinal axis). And as shown, this is also an example of a method in which the entire first expandable member 1110 is within an AA. This is also an example of a method in which at least half of the first impeller 1116 is positioned within AA, and is also an embodiment in which the entire first impeller 1116 is positioned within AA.

At any time during or after deployment of the pump portion 1104, the position of the pump portion may be assessed in any manner, such as under fluoroscopy. The position of the pump section may be adjusted at any time during or after deployment. For example, after releasing the second expandable stent 1110 but before releasing the first expandable member 1108, the pump portion 1104 may be moved axially (distally or proximally) to reposition the pump portion. Further, for example, the pump portion may be repositioned after the entire working portion has been released from the sheath to the desired final position.

It should be appreciated that the positions of the components shown in fig. 4 (relative to the anatomy) are considered exemplary final positions of the different components of working portion 1104, even if repositioning occurs after initial deployment.

The one or more expandable members herein may be configured and expandable in a variety of ways, such as by self-expansion, mechanical actuation (e.g., one or more axially directed forces on the expandable member that are expanded with a separate balloon positioned radially within the expandable member and that is inflated to urge the expandable member radially outward), or a combination thereof.

Expansion, as used herein, generally refers to a larger profile reconfigured to have a larger radially outermost dimension (relative to the longitudinal axis), regardless of the particular manner in which one or more components are expanded. For example, a scaffold that is self-expanding and/or is subjected to a radially outward force may be "expanded," as that term is used herein. The expanded or opened device may also present a larger profile and may be considered expanded as that term is used herein.

The impellers may be similarly adapted and configured and may be expanded in various ways depending on their structure. For example, one or more impellers may automatically revert to or towards a different larger profile configuration upon release from the sheath due to the materials and/or structures of the impeller design (see, e.g., U.S. patent No. 6,533,716 or U.S. patent No. 7,393,181, both of which are incorporated herein by reference for all purposes). Thus, in some embodiments, retraction of the external restraint device may allow both the expandable member and the impeller to naturally revert to a larger profile deployed configuration without any further actuation.

As shown in the example of fig. 4, the working portion includes a first impeller and a second impeller spaced apart on either side of the aortic valve, each impeller disposed within a separate expandable member. This is in contrast to some designs in which the working portion comprises a single elongate expandable member. Working end 1104 includes a conduit 1112 extending between expandable members 1108 and 1110, rather than a single generally tubular expandable member extending all the way through the valve. The conduit is more flexible and deformable than an expandable cage (basket), which can allow greater deformation of the working portion at the leaflet location than would occur if the expandable member had spanned the aortic valve leaflet. This may cause less damage to the leaflets after the working portion has been deployed in the subject.

Furthermore, forces from the leaflets acting on the central region of a single expandable member may translate axially to other regions of the expandable member, possibly resulting in undesired deformation of the expandable member at the location of one or more impellers. This may cause the outer expandable member to contact the impeller, undesirably interfering with the rotation of the impeller. Including designs of separate expandable members around each impeller, particularly designs in which each expandable member and each impeller are supported at both ends (i.e., distal and proximal ends), results in a high level of precision in positioning the impeller relative to the expandable members. Two separate expandable members may be able to more reliably maintain their deployed configuration than a single expandable member.

As described herein above, it may be desirable to be able to reconfigure the working portion so that the working portion may be delivered within a 9F sheath and still achieve a sufficiently high flow rate when in use, which is not possible with some products currently being developed and/or tested. For example, some products are too large to reconfigure to a sufficiently small delivery profile, while some smaller designs may not achieve the required high flow rates. An exemplary advantage of the examples in fig. 1, 2, 3A-3D, and 4 is that, for example, the first impeller and the second impeller may work together to achieve a desired flow rate, and by having two axially spaced impellers, the entire working portion may be reconfigured to a smaller delivery profile than designs that use a single impeller to achieve the desired flow rate. Thus, these embodiments use a plurality of smaller reconfigurable impellers that are axially spaced apart to achieve the desired smaller delivery profile and to achieve the desired high flow rates. However, it should be understood that these or any other embodiments in this disclosure may include only a single impeller, such as only a proximal impeller or only a distal impeller.

Fig. 5 shows a working part similar to the working part shown in fig. 1. Working portion 265 includes a proximal impeller 266, a distal impeller 267, both of which proximal impeller 266 and distal impeller 267 are coupled to a drive shaft 278 that extends into distal bearing housing 272. At the proximal end of the working portion there is a similar proximal bearing housing. The working portion also includes an expandable stent or member (generally referred to as 270) and a blood conduit 268, the blood conduit 268 being secured to the expandable member and extending nearly the entire length of the expandable member. The expandable member 270 includes a distal strut 271, the distal strut 271 extending to a strut support 273 and being secured to the strut support 273, the strut support 273 being secured to the distal tip 273. The expandable member 270 also includes a proximal strut secured to the proximal strut support. All features similar to those shown in fig. 1 are incorporated by reference into this embodiment for all purposes, even if not explicitly stated. The expandable member 265 further includes a helical tension member 269 disposed along a perimeter of the expandable member, and the helical tension member 269 has a helical configuration when the expandable member is in the expanded configuration as shown. The helical tension member 269 is configured and adapted to induce rotational entanglement upon collapse. Working portion 265 may collapse from the expanded configuration shown while rotating one or both impellers at a relatively slow speed to facilitate crimping collapse of the impellers due to interaction with the expandable member. The helical tension member 269 (or helical arrangement of expandable member units) will act as a collective tension member and be configured such that when the expandable cage is pulled along its length to collapse (e.g., by stretching to a much greater length, e.g., approximately doubling the length), the tension member 269 is pulled into a more straight arrangement, which causes the desired segment of the expandable member to rotate/twist during collapse, which causes the impeller blades to wind radially inward as the expandable member and blades collapse. When in a helical form, an exemplary configuration of such a tension member will have a curvilinear configuration that is approximately equal to the maximum length of the expandable member when collapsed. In an alternative embodiment, only the portion of the expandable member surrounding the collapsible impeller is caused to rotate upon collapse.

There are alternative ways to construct the working portion to cause rotation of the expandable member (and thus the wrapping and collapsing of the impeller blades) when collapsed by elongation. Any expandable member can be constructed with this feature, even in a dual impeller design. For example, for an expandable member comprising a plurality of "cells," as that term is commonly known (e.g., laser cut elongated members), the expandable member may have a plurality of particular cells that together define a particular configuration, such as a spiral configuration, wherein the cells defining the configuration have different physical properties than other cells in the expandable member. In some embodiments, the expandable member may have a braided structure, and the twisted region may constitute the entire wire set, or a majority (e.g., more than half) of the braided wire. Such a twisted braid structure may be achieved, for example, during braiding, for example by twisting the mandrel to which the wire is braided as the mandrel is pulled (particularly along the length of the largest diameter portion of the braided structure). The structure may also be completed during a second operation of the construction process, such as mechanically twisting the braided structure prior to heat setting the winding profile on the forming mandrel.

Any blood tubing herein acts on, is configured to create, and is made of, a material between a first end (e.g., distal end) and a second end (e.g., proximal end) in which a fluid lumen is created. Fluid flows into the inflow region, through the fluid lumen, and out of the outflow region. The flow to the inflow region may be labeled "I" herein, and the outflow at the outflow region may be labeled "O". Any of the conduits herein may be impermeable. Any of the conduits herein may alternatively be semi-permeable. Any conduit herein may also be porous, but still define a fluid lumen therethrough. In some embodiments, the conduit is a film or other relatively thin layered member. Unless otherwise indicated, any conduit herein may be secured to the expandable member such that the conduit may be located radially inside and/or outside of the expandable member where it is secured. For example, the conduit may extend radially within the expandable member such that, with the conduit secured to the expandable member, an inner surface of the conduit is located radially within the expandable member.

Any of the expandable stents or members herein may be constructed from a variety of materials and in a variety of ways. For example, the expandable member may have a braided structure, or the expandable member may be formed by laser processing. The material may be deformable, for example nitinol. The expandable member may be self-expanding or may be adapted to actively expand at least in part.

In some embodiments, the expandable stent or member is adapted to self-expand upon release from within a receiving tubular member (e.g., a delivery catheter, guide catheter, or access sheath). In some alternative embodiments, the expandable member is adapted to be expanded by active expansion, such as by the action of a tie rod that moves at least one of the distal and proximal ends of the expandable member toward each other. In alternative embodiments, the deployed configuration may be affected by the configuration of one or more expandable structures. In some embodiments, one or more expandable members may be deployed at least in part by the influence of blood flowing through the conduit. Any combination of the above expansion mechanisms may be used.

The blood pumps and fluid movement devices, systems and methods herein may be used and positioned at various locations within the body. Although specific examples may be provided herein, it should be understood that the working portion may be positioned in a different body area than the body area specifically described herein.

In any embodiment in which the catheter blood pump comprises a plurality of impellers, the apparatus may be adapted to cause the impellers to rotate at different speeds. Fig. 6A illustrates a medical device including a gear set 1340 coupled to both an inner drive member 1338 and an outer drive member 1336, the inner drive member 1338 and the outer drive member 1336 in operative communication with a distal impeller 1334 and a proximal impeller 1332, respectively. The apparatus also includes a motor 1342, the motor 1342 driving rotation of the inner drive member 1338. The inner drive member 1338 extends through the outer drive member 1336. Activation of the motor 1332 causes the two impellers to rotate at different speeds due to the low or overdrive ratio. The gear set 1340 may be adapted to drive the proximal impeller or the distal impeller faster than the other. Any of the devices herein may include any of the gear sets herein to drive the impeller at different speeds.

Fig. 6B shows a portion of an alternative embodiment of a dual impeller apparatus (1350) that is also adapted to cause different impellers to rotate at different speeds. The gear set 1356 is coupled to both the inner drive member 1351 and the outer drive member 1353, and the inner drive member 1351 and the outer drive member 1353 are coupled to the distal impeller 1352 and the proximal impeller 1354, respectively. The apparatus also includes a motor similar to that of fig. 6A. Fig. 6A and 6B illustrate how the gear set is adapted to drive the proximal impeller slower or faster than the distal impeller.

Fig. 7 illustrates an exemplary alternative embodiment of a fluid pump 1370, the fluid pump 1370 may rotate the first and second impellers at different speeds. The first motor 1382 drives a cable 1376 coupled to the distal impeller 1372, and the second motor 1384 drives an external drive member 1378 (through a gear set 1380) coupled to the proximal impeller 1374. A drive cable 1376 extends through the outer drive member 1378. The motors can be controlled and operated individually and thus the speeds of the two impellers can be controlled individually. The system arrangement may be used in any system herein that includes multiple impellers.

In some embodiments, a common drive mechanism (e.g., cable and/or shaft) may drive rotation of two (or more) impellers, but the blade pitch (angle of rotation curvature) of the two impellers may be different, with either the distal impeller or the proximal impeller having a steeper or more gradual angle than the other impeller. This may produce an effect similar to a gear set. Fig. 6C shows a portion of a medical device (1360) including a common drive cable 1366 coupled to a proximal impeller 1364 and a distal impeller 1362 and a motor (not shown). The proximal impeller herein may have a larger or smaller pitch than the distal impeller herein. Any working portion (or distal portion) having a plurality of impellers herein may be modified to include a first impeller and a second impeller having different pitches.

In any of the embodiments herein, the pump portion may have a compliant or semi-compliant (often collectively referred to as "compliant") outer structure. In various embodiments, the compliant portion is flexible. In various embodiments, the compliant portion only partially deforms under pressure. For example, the central portion of the pump may be formed from a compliant outer structure such that it deforms in response to the forces of the valve. In this way, the external force of the pump to the valve leaflet is reduced. This helps to prevent damage to the valve at the location where the pump spans the valve.

Fig. 8 illustrates an exemplary embodiment of a pump portion including axially spaced first, second and third impellers 152, each of the first, second and third impellers 152 disposed within an expandable member 154. The tubing 155 may extend along the length of the pump portion, which may help create and define a fluid lumen, as described in various embodiments herein. However, in alternative embodiments, the first impeller, the second impeller, and the third impeller may be disposed within a single expandable member, similar to that shown in fig. 1. In fig. 8, the fluid lumen extends from a distal end to a proximal end, which is characterized elsewhere herein. The embodiment of fig. 8 may include any other suitable features described herein, including methods of use.

The embodiment in fig. 8 is also an example of an outer housing having at least one bend formed therein between a proximal impeller distal end and a distal impeller proximal end such that a distal region of the housing distal from the bend is not axially aligned with a proximal region of the housing proximal to the bend along an axis. In this embodiment, two curved portions 150 and 151 are formed in the housing, each curved portion 150 and 151 being between two adjacent impellers.

In one method of use, the curve formed in the housing can be positioned across a valve, such as the aortic valve shown in fig. 8. In this placement method, the central impeller and the most distal impeller are located in the left ventricle and the most proximal impeller is located in the ascending aorta. The curvature 151 is located just downstream of the aortic valve.

Bends such as bends 150 or 151 may be incorporated into any of the embodiments or designs herein. The curvature may be a preformed angle or may be adjustable in situ.

In any of the embodiments herein, the outer housing can have a substantially uniform diameter along its length unless otherwise indicated.

In fig. 8, the pump is positioned through the axillary artery, which is an exemplary method of accessing the aortic valve and allowing the patient to walk and move with less disruption. Any of the devices herein may be positioned through the axillary artery. However, as will be appreciated from the description herein, the pump may be introduced and tracked in place in a variety of ways, including femoral access on the aortic arch.

One aspect of the present disclosure is a catheter blood pump that includes a distal impeller axially spaced from a proximal impeller. The distal and proximal impellers may be axially spaced apart from each other. For example, the distal and proximal impellers may be connected to a common drive mechanism only by their separate accessories. This is different from a single impeller having multiple blade rows or sections. The phrase "distal impeller" as used herein does not necessarily refer to the most distal impeller of the pump, but may generally refer to an impeller that is positioned more distally than the proximal impeller, even if there is an additional impeller that is disposed more distally than the distal impeller. Similarly, the phrase "proximal impeller" as used herein does not necessarily mean the most proximal impeller of the pump, but may generally refer to an impeller that is positioned more proximally than the proximal impeller, even if there is an additional impeller disposed more proximally than the proximal impeller. Axial spacing (or some derivative thereof) refers to spacing along the length of the pump portion, such as along the longitudinal axis of the pump portion, even if bends are present in the pump portion. In various embodiments, each of the proximal and distal impellers are positioned within a respective housing and are configured to maintain a precise, consistent tip clearance, and the span between impellers has a relatively more flexible (or fully flexible) fluid lumen. For example, each impeller may be positioned within a respective housing having a relatively rigid outer wall to prevent radial collapse. The section between the impellers may be relatively rigid, and in some embodiments, the section is primarily held open by the internal fluid pressure.

Although not required by embodiments therein, it may be advantageous to have a minimum axial spacing between the proximal and distal impellers. For example, the pump portion may be delivered to the target site through an anatomical portion (e.g., the aorta) having a relatively tight curve and down into the aortic valve. For example, the pump portion may be delivered through a femoral artery access and to an aortic valve. It may be advantageous to have a system that is more flexible, so that it is easier to deliver the system through bends in the anatomy. Some designs in which the multiple impellers are very close to each other may make the system relatively stiff along the length across the multiple impellers along the entire length of the multiple impellers. Axially spacing the impellers and optionally providing a relatively flexible region between the impellers may result in a system portion that is more flexible, and may more easily and safely advance through the bend. Another exemplary advantage is that the axial spacing may allow for a relatively more compliant region between the impellers that may be located, for example, at the site of a valve (e.g., an aortic valve). In addition, there are other potential advantages and functional differences between the various embodiments herein and typical multi-stage pumps. A typical multistage pump includes rows of blades (sometimes referred to as impellers) in closely spaced functioning intervals such that the rows of blades together act as a synchronous stage. It will be appreciated that as the flow passes through the distal impeller, the flow may separate. In various embodiments described herein, the distal impeller and the proximal impeller may be sufficiently spaced apart such that flow separation from the distal impeller is greatly reduced (i.e., increased flow reattachment) and local turbulence is dissipated before the flow enters the proximal impeller.

In any embodiment including a distal impeller and a proximal impeller or in any portion described herein, the axial spacing between the distal end of the proximal impeller and the proximal end of the distal impeller may be from 1.5cm to 25cm (including 1.5cm and 25 cm) along the longitudinal axis of the pump portion or along the longitudinal axis of the housing portion including the fluid lumen. This distance can be measured when the pump section including any impeller is in the expanded configuration. This exemplary range may provide the exemplary flexibility benefits described herein when the pump portion is delivered through a curved portion of the anatomy (e.g., via the aortic valve of the aorta). Fig. 9 (shown outside the patient in the expanded configuration) shows a length Lc that shows the axial spacing between the impellers, and may be 1.5cm to 25cm in some embodiments, as described herein. In embodiments where there may be more than two impellers, any two adjacent impellers (i.e., impellers without any other rotating impeller therebetween) may be axially spaced apart by any of the axial spacing distances described herein.

While some embodiments include a proximal impeller distal end axially spaced from the distal impeller proximal end along the axis by 1.5cm to 25cm, the disclosure herein also includes any axial spacing within a subrange within the general range of 1.5cm to 25 cm. That is, the present disclosure includes all ranges having any lower limit of 1.5cm and above within the range, and all subranges having any upper limit of 25cm and below. The following examples provide exemplary subranges. In some embodiments, the proximal impeller distal end is axially spaced from the distal impeller proximal end along the axis by 1.5cm to 20cm, 1.5cm to 15cm, 1.5cm to 10cm, 1.5cm to 7.5cm, 1.5cm to 6cm, 1.5cm to 4.5cm, 1.5cm to 3cm. In some embodiments, the axial spacing is 2cm to 20cm, 2cm to 15cm, 2cm to 12cm, 2cm to 10cm, 2cm to 7.5cm, 2cm to 6cm, 2cm to 4.5cm, 2cm to 3cm. In some embodiments, the axial spacing is 2.5cm to 15cm, 2.5cm to 12.5cm, 2.5cm to 10cm, 2.5cm to 7.5cm, or 2.5cm to 5cm (e.g., 3 cm). In some embodiments, the axial spacing is 3cm to 20cm, 3cm to 15cm, 3cm to 10cm, 3cm to 7.5cm, 3cm to 6cm, or 3cm to 4.5cm. In some embodiments, the axial spacing is 4cm to 20cm, 4cm to 15cm, 4cm to 10cm, 4cm to 7.5cm, 4cm to 6cm, or 4cm to 4.5cm. In some embodiments, the axial spacing is 5cm to 20cm, 5cm to 15cm, 5cm to 10cm, 5cm to 7.5cm, or 5cm to 6cm. In some embodiments, the axial spacing is 6cm to 20cm, 6cm to 15cm, 6cm to 10cm, or 6cm to 7.5cm. In some embodiments, the axial spacing is 7cm to 20cm, 7cm to 15cm, or 7cm to 10cm. In some embodiments, the axial spacing is 8cm to 20cm, 8cm to 15cm, or 8cm to 10cm. In some embodiments, the axial spacing is 9cm to 20cm, 9cm to 15cm, or 9cm to 10cm. In various embodiments, the fluid cavity between the impellers is relatively unsupported.

In any of the embodiments herein, one or more impellers may have a length measured axially between the impeller distal end and the impeller proximal end of from 0.5cm to 10cm or any subrange thereof (shown in fig. 9 as "L", respectively _SD "and" L _SP "). The following examples provide exemplary subranges. In some embodiments, the impeller axial length is 0.5cm to 7.5cm, 0.5cm to 5cm, 0.5cm to 4cm, 0.5cm to 3cm, 0.5cm to 2cm, or 0.5cm to 1.5cm. In some embodiments, the impeller axial length is 0.8cm to 7.5cm, 0.8cm to 5cm, 0.8cm to 4cm, 0.8cm to 3cm, 0.8cm to 2cm, or 0.8cm to 1.5cm. In some embodiments, the impeller axial length is 1cm to 7.5cm, 1cm to 5cm, 1cm to 4cm, 1cm to 3cm, 1cm to 2cm, or 1cm to 1.5cm. In some embodiments, the impeller axial length is 1.2cm to 7.5cm, 1.2cm to 5cm, 1.2cm to 4cm, 1.2cm to 3cm, 1.2cm to 2cm, or 1.2cm to 1.5cm. In some embodiments, the impeller axial length is 1.5cm to 7.5cm, 1.5cm to 5cm, 1.5cm to 4cm, 1.5cm to 3cm, or 1.5cm to 2cm. In some embodiments, the impeller axial length is 2cm to 7.5cm, 2cm to 5cm, 2cm to 4cm, or 2cm to 3cm. In some embodiments, the impeller axial length is 3cm to 7.5cm, 3cm to 5cm, or 3cm to 4cm. In some embodiments, the impeller axial length is 4cm to 7.5cm, or 4cm to 5cm.

In any of the embodiments herein, the fluid lumen may have a length from the distal end to the proximal end, shown as length Lp in fig. 9. In some embodiments, the fluid lumen length Lp is 4cm to 40cm, or any subrange therein. For example, in some embodiments, the length Lp may be 4cm to 30cm, 4cm to 20cm, 4cm to 18cm, 4cm to 16cm, 4cm to 14cm, 4cm to 12cm, 4cm to 10cm, 4cm to 8cm, 4cm to 6cm.

In any of the embodiments herein, the stent (also referred to as the housing) may have a deployed (expanded) diameter (e.g., outer diameter) at least at the location of the impellers (and optionally between the impellers), shown as dimension Dp in fig. 9. In some embodiments, dp may be 0.3cm to 1.5cm (3.0 mm to 15.0 mm), or any subrange therein. For example, dp may be 0.4cm to 1.4cm, 0.4cm to 1.2cm, 0.4cm to 1.0cm, 0.4cm to 0.8cm, or 0.4cm to 0.6cm. In some embodiments, dp may be 0.5cm to 1.4cm, 0.5cm to 1.2cm, 0.5cm to 1.0cm, 0.5cm to 0.8cm, or 0.5cm to 0.6cm, 0.5cm to 0.8cm, or 0.5cm to 1.0cm. In some embodiments, dp may be 0.6cm to 1.4cm, 0.6cm to 1.2cm, 0.6cm to 1.0cm, or 0.6cm to 0.8cm. In some embodiments, dp may be 0.7cm to 1.4cm, 0.7cm to 1.2cm, 0.7cm to 1.0cm, or 0.7cm to 0.8cm.

In any of the embodiments herein, the impeller may have a deployed diameter, shown as dimension D of fig. 9 _I . In some embodiments, D _I May be from 1mm to 30mm, or any subrange therein. For example, in some embodiments, D _I May be 1mm-15mm, 2mm-12mm, 2.5mm-10mm or 3mm-8mm.

In any of the embodiments herein, there is an end gap between the impeller outer diameter and the fluid inner cavity inner diameter. In some embodiments, the tip gap may be 0.01mm to 1mm, such as 0.05mm to 0.8mm, or such as 0.1mm-0.5mm.

In any embodiment herein comprising multiple impellers, the axial spacing between the impellers (along the length of the pump section even if bends are present in the pump section) may be from 2mm to 100mm, or any combination of upper and lower limits including 5mm and 100mm (e.g., 10mm-80mm, 15mm-70mm, 20mm-50mm, 2mm-45mm, etc.).

Any pump section herein comprising a plurality of impellers may also comprise more than two impellers, such as three, four or five impellers (for example).

In any of the embodiments herein, the diameter (e.g., inner diameter) of the stent (also referred to as a housing) in a collapsed state (e.g., for sheathing) may be 2.0mm to 7.0mm, or any subrange therein. For example, the diameter (e.g., inner diameter) of the stent in the collapsed state may be 2.0mm to 2.5mm, 2.0mm to 3.0mm, 2.0mm to 4.0mm, 2.0mm to 5.0mm, 2.0mm to 6.0mm, 2.5mm to 4.5mm, 2.5mm to 6.0mm, 3.0mm to 6.0mm, or 3.0mm to 4.5mm.

Fig. 10 shows an expandable stent 250, which expandable stent 250 may be one of at least two expandable stents of a pump section, such as the expandable stents of fig. 3A-3D, wherein each expandable stent at least partially surrounds an impeller. The stent design in fig. 10 has proximal struts 251 (only one labeled) extending axially therefrom. Having a separate expandable stent 250 for each impeller provides the ability to have different geometries for any single impeller. Furthermore, this design reduces the amount of stent material (e.g., nitinol) over the length of the expandable blood tubing, which may provide increased tracking when sheathed. Potential challenges for these designs may include creating a continuous membrane between the expandable stents without axially extending stent material (see fig. 3A). Any other aspect of the expandable stent or member herein (such as those described in fig. 3A-3D) may be incorporated into this exemplary design by reference. The struts 251 may be provided at the pump inflow or outflow. Struts 251 may be proximal struts or they may be distal struts.

Fig. 11 shows an exemplary stent along the length of a blood conduit. The central region "CR" may be axially located between the proximal and distal impellers. The flexibility of the central region "CR" is increased relative to the stent impeller region "IR" due to the stent morphology in the central region having breaks or discontinuities. The support has a relatively more rigid impeller section "IR" adjacent the central region where an impeller (not shown) may be provided. The relatively increased rigidity in the impeller region IR may help maintain tip clearance and impeller concentricity. This pump stent morphology provides a flexible distribution of a relatively less flexible proximal section ("IR") along its length, a relatively more flexible central region "CR", and a distal section "IR" that is relatively less flexible than the central region. The relatively less flexible sections (i.e., the two IR regions) are where the proximal and distal impellers may be disposed (not shown, but other embodiments are fully incorporated herein in this regard) while having relatively more flexible regions between the relatively less flexible sections. Exemplary benefits of relative flexibility in these respective sections are described elsewhere herein. Fig. 11 is an example of a stent that is continuous from a first end region to a second end region, even if there are breaks or discontinuities at some locations of the stent. At least one line may be traced along a continuous structural path from the first end region to the second end region.

The following disclosure provides exemplary method steps that may be performed when using any of the blood pumps described herein, or portions thereof. It should be understood that not all steps need be performed, but rather that the steps are intended to be illustrative processes. It is also intended that the order of one or more steps may be different in some cases, if appropriate. Prior to use, the blood pump may be prepared for use by priming the lumen (including any annular space) and pump assembly with a sterile solution (e.g., heparinized saline) to remove any air bubbles from any fluid lines. A conduit comprising any number of purge lines may then be connected to the console. Alternatively, the catheter may be connected to a console and/or a separate pump for priming the catheter to remove air bubbles.

After the catheter is irrigated, access to the patient's vasculature (e.g., without limitation, through a femoral approach) may be obtained using an appropriately sized introducer sheath. Using standard valve crossing techniques, the diagnostic pigtail catheter can then be advanced over, for example, a 0.035 "guidewire until the pigtail catheter is securely positioned at the target site (e.g., left ventricle). The guidewire may then be removed and a second wire 320 (e.g., a 0.018 "wire) may be inserted through the pigtail catheter. The pigtail catheter (see fig. 12A) may then be removed and the blood pump 321 (including the catheter, catheter sheath, and pump portion within the sheath; see fig. 12B) may be advanced over a second wire toward a target location, such as across the aortic valve "AV", and into the target location (e.g., left ventricle "LV"), using, for example, one or more radiopaque markers to position the blood pump.

Once proper placement is confirmed, the catheter sheath 322 (see fig. 12C) can be retracted, first exposing the distal end region of the pump portion. In fig. 12C, the distal region of the expandable housing has been released from the sheath 322 and expanded, as has the distal impeller 324. The proximal end of the housing 323 and the proximal impeller have not been released from the sheath 322. Continued retraction of the sheath 322 beyond the proximal end of the housing 323 allows the housing 323 and proximal impeller 325 to expand (see fig. 12D). The inflow region (shown with arrows, even though the impeller has not rotated) and the distal impeller are located in the left ventricle. The outflow (shown with arrows, even though the impeller has not yet rotated) and the proximal impeller are located in the ascending aorta AA. As described in more detail herein, the outer housing region (which may be more flexible than the housing region surrounding the impellers) between the two impellers spans the aortic valve AV. In the exemplary operating position as shown, the inlet portion of the pump portion will be distal to the aortic valve in the left ventricle and the outlet of the pump portion will be proximal to the aortic valve in the ascending aorta ("AA").

The second wire (e.g., a 0.018 "guidewire) may then be moved prior to operation of the pump assembly (see fig. 12E). If desired or required, the pump portion may deflect (actively or passively) at one or more locations, as described herein, as shown in fig. 12F. For example, the area between the two impellers may be deflected by tensioning a tensioning member that extends to a position between the two impellers. Deflection may be desired or required to accommodate a particular anatomy. The pump section may be repositioned as desired to achieve the desired placement, for example, with a first impeller on one side of the heart valve and a second impeller on a second side of the heart valve. It should be appreciated that in fig. 12F, the pump portion does not interfere with or interact with the mitral valve in any way, even though this may be the case from the figure.

As described above, the present disclosure includes a catheter blood pump including an expandable pump portion extending distally relative to a catheter. The pump portion includes an impeller housing including an expandable blood conduit defining a blood lumen. The blood conduit may include one or more stent sections, which may also be referred to herein together as a single stent. In some exemplary embodiments, the expandable blood tubing may include one or more of a proximal impeller support, a distal impeller support, and a central support disposed between the proximal impeller support and the distal impeller support, wherein any combination thereof may also be referred to herein as a support. Any individual proximal or distal impeller support may also be referred to herein as an expandable member, as shown in fig. 3A-3D. In some embodiments, the expandable blood tubing may include a proximal impeller support and an additional support extending distally therefrom, for example if the pump portion includes a proximal impeller but does not include a distal impeller. In any of the embodiments herein, reference to a distal impeller is by way of example only, and the pump portion herein need not include a distal impeller. The center stent herein is typically less stiff in response to radially inward forces than the proximal stent and optionally less stiff than the distal stent (e.g., distal impeller stent) as well. Exemplary advantages of the less stiff central support portion are set forth elsewhere herein. The blood conduit may further include a membrane coupled to the one or more stents, the membrane at least partially defining a blood lumen. In this case, the membrane may incorporate the disclosure of the catheter, including any of the features or manufacturing methods described above, by reference herein. The catheter blood pump may include an impeller disposed in a proximal region of an impeller housing, which may be a proximal impeller. The catheter blood pump may further comprise a distal impeller located in a distal region of the impeller housing. Exemplary impellers, including exemplary proximal and distal impellers, are set forth herein as examples. The impeller may be described as being located at least partially within a portion of the stent, such as a proximal impeller within at least a portion of a proximal stent, or a distal impeller within at least a portion of a distal stent, relative to the relative position of the stent.

While the proximal impeller is described as being located within the proximal bracket, it should be understood that the proximal bracket need not extend axially the entire length of the impeller so long as there is some amount of axial overlap. For example, some of the proximal impellers herein extend proximally from the blood conduit and the proximal region of the proximal impeller is not surrounded by the blood conduit stent while the distal region of the impeller is surrounded by the stent. Similarly, while the distal impeller (if the pump includes a distal impeller) is described herein as being within a distal stent, it should be understood that the distal stent need not extend axially the entire length of the impeller, so long as there is some degree of axial overlap therebetween.

Fig. 13A-17 illustrate exemplary designs of expandable stents herein that may at least partially surround an impeller disposed at least partially within a conduit creating a fluid lumen. The stent morphology in fig. 13A-17 may be a stent morphology that extends only over a particular impeller (e.g., proximal cage or distal cage), or the stent morphology may be a stent morphology that extends over the entire blood conduit stent.

Fig. 13A-17 illustrate expandable support members or stents each having an expanded configuration wherein the support member has a plurality of continuous axially extending elements (e.g., 408, 410, 420, 430, 440) that are continuous and extend the length (e.g., L) of the expandable support member _s ) And wherein the expandable support member includes a plurality of sets of connectors (e.g., 412/414, 409, 422/424, 432/434, 442/444), each set of connectors extending between first and second circumferentially adjacent consecutive axially extending elements. In some embodiments, the axially extending element is linear or substantially linear.

Fig. 13A-13C illustrate an exemplary pump portion 400, or a portion thereof, that includes an expandable impeller housing 402 having a blood conduit 404 defining a blood lumen between a housing inflow "I" and a housing outflow "O". The expandable impeller housing further includes an expandable bracket or support member 406 at least partially surrounding an impeller (not shown in fig. 13A-13C) disposed at least partially within the conduit. Fig. 14A-17 illustrate an expandable stent of a pump section. It should be understood that any of the expandable stents of any of fig. 13A-17 may be used in place of any of the expandable stents herein. The impeller housing 402 may show the entire impeller housing, or the impeller housing 402 may represent only a portion thereof, including only a single carrier section, e.g., having any multi-lobed wheel design herein. Thus, it will be appreciated that the structure shown in FIGS. 13A-13C may be only a portion of the expandable housing of the pump section. For example, the pump portion may include two expandable stent sections axially spaced apart as shown in fig. 13A-13C and coupled by, for example, a flexible membrane.

Fig. 13A-13C illustrate an expandable impeller housing including a plurality of axially extending elements 408, the axially extending elements 408 being circumferentially spaced from adjacent axially extending elements around the housing 402, as shown. Fig. 13A and 13B illustrate the expanded configuration of the housing, while fig. 13C illustrates the model in a flat unexpanded configuration with integral struts 401 extending axially therefrom, as shown. For simplicity, in the context of stents, a plurality of axially extending elements may be referred to as "elements," but it should be understood that they are not considered herein to be any other type of "element," unless specifically indicated. The elements in this embodiment may be axial and linear in the expanded configuration of the housing. The expandable stent 406 also includes a circumferential connector 409, the circumferential connector 409 circumferentially connecting and extending from one axial element to an adjacent axial element. In this exemplary embodiment, all connectors have the same overall configuration, including a first segment and a second segment that meet at a rounded peak that is oriented axially (proximally or distally, depending on the frame of reference), otherwise denoted as axially directed. The length Ls of the stent and the length Le of the element are shown in fig. 13C. An optional post 401 (which may be integral with the bracket) is shown. The axial element 408 in this embodiment extends from the first axial element end 405 to the second axial element end 405', which extends nearly the entire length Ls of the stent. As shown, the ends 405 'of the elements (only one labeled) extend to the distal end region 407' of the stent 406. The end 405 extends to a proximal end region 407. The pump section also includes a transition region 411, which transition region 411 includes circumferentially extending portions of adjacent axial elements after which they meet to form the strut 401, as shown.

Fig. 14A (expanded) and 14B (unexpanded) illustrate an exemplary expandable stent 406', the expandable stent 406' including a plurality of axially extending elements 410. The first set of connectors 412 has an "S" configuration and the second set of circumferentially adjacent connectors 414 has an opposite (reverse) "S" shape. In the expanded configuration of fig. 14A, the axial element 410 may be linear, or the axial element 410 may have a slightly curvilinear configuration as shown. The support 406' includes a transition region 411', and the transition region 411' may have similar features as the transition region 411 herein. The stent of fig. 14A-14B may contain relevant descriptions from any other embodiment (e.g., the length of the stent or support member and axial element, transition regions, etc.). Some optional struts 413 are shown, as well as the ends 405/405' of the axial elements. The support 406 'may be a proximal support or a distal support, or the support 406' may extend along the length of the impeller housing.

Fig. 15A and 15B illustrate an exemplary expandable stent 406) similar to the stent of fig. 13A-13C, 14A-14B, 16 and 17. An axially extending element 420 is shown wherein adjacent axial elements are connected by circumferential connectors 422 and 424, the ends of the circumferential connectors 422 and 424 being axially offset. The first set of connectors 422 have a generally S-configuration, while the second set of connectors 424 are inverted S-shaped. In this embodiment, the axially extending element 420 is curvilinear, as shown. The S-shaped and reverse S-shaped configurations alternate around the expandable member as in the stent of fig. 14A and 14B. The support 406 "also includes a transition region 421, examples of which are described elsewhere herein. The support 406 "may be a proximal support or a distal support, or the support 406" may extend along the length of the impeller housing.

Fig. 16 illustrates a collapsed (undeployed) configuration of an exemplary stent 406", which stent 406" may have any other support members or any other suitable features of a stent herein. An axially extending member 430 is shown connected by a first set of S-connectors 434 and a second set of inverted S-connectors 432. As shown, the S-shaped and inverted S-shaped configurations alternate circumferentially around the support 406 ". The support 406 "may be a proximal support or a distal support, or the support 406" may extend along the length of the impeller housing.

Fig. 17 illustrates a collapsed (undeployed) configuration of an exemplary stent 406"", which stent 406"" may have any other support member or any other suitable feature of a stent herein. An axially extending element 440 is shown connected by a reverse S-shaped connector. All connector sets (e.g., sets 442 and 444) in this embodiment have the same configuration and are inverted S-shaped in this embodiment. The exemplary struts are shown as being axially disposed relative to the stent 406"", and the stent 406"" "may include transition sections as described elsewhere herein. The support 406"" may be a proximal support or a distal support, or the support 406"" may extend along the length of the impeller housing.

The stent and blood tubing embodiments in fig. 13A-17 are illustrative and may be modified to include aspects of other embodiments herein. The following description may provide modifications to the stent of fig. 13A-17, any of which may be incorporated into any of the stents of fig. 13A-17.

In any of the stents illustrated in fig. 13A-17, at least a first end of each of the plurality of axially extending elements may extend to one or more of a proximal end region (e.g., 417', 407') and a distal end region (e.g., 417) of the expandable stent.

In any of the stents illustrated in fig. 13A-17, at least one of the plurality of axially extending elements and optionally all of the axially extending elements may be linear. In any of the stents illustrated in fig. 13A-17, at least one of the plurality of axially extending elements and optionally all of the axially extending elements may be curvilinear.

In any of the stents illustrated in fig. 13A-17, each of the plurality of axially extending elements may have a proximal end and a distal end, wherein the proximal and distal ends are substantially circumferentially aligned.

In any of the stents shown in fig. 13A-17, each of the plurality of axially extending elements may have a circumferential span (shown as "CS" in fig. 15A) that is no greater than 10 degrees circumferentially around the expandable stent, alternatively no greater than 5 degrees of the expandable stent.

In any of the stents shown in fig. 13A-17, each of the plurality of axially extending elements may follow a path that is substantially parallel to the longitudinal axis of the expandable stent.

In any of the embodiments of fig. 13A-17, each of the plurality of axially extending elements may be continuous and axially extend within at least 55% of the length of the expandable stent, optionally within at least 60% of the length of the expandable stent, optionally within at least 65% of the length of the expandable stent, optionally within at least 70% of the length of the expandable stent, optionally within at least 75% of the length of the expandable stent, optionally within at least 80% of the length of the expandable stent, optionally within at least 85% of the length of the expandable stent, optionally within at least 90% of the length of the expandable stent, optionally within at least 95% of the length of the expandable stent.

In any of the stents shown in fig. 13A-17, all of the connectors in all of the sets of connectors may have the same configuration. In any of the stents shown in fig. 13A-17, all of the connectors in all of the sets of connectors may not have the same configuration. In any of the stents shown in fig. 13A-17, each set of individual connectors may have a plurality of connectors having the same configuration. In any of the embodiments of fig. 13A-17, all connectors in all groups of multiple groups of connectors may have an S-shape. In any of the embodiments of fig. 13A-17, all connectors in all groups of multiple groups of connectors may have an inverted (or reverse) S shape. In any of the brackets shown in fig. 13A-17, all of the connectors in the first set of connectors may have an S-shape. In any of the stents shown in fig. 13A-17, the second set of connectors circumferentially adjacent to the first set of connectors may all have a reverse S shape. In any of the stents shown in fig. 13A-17, the S-shape/reverse S-shape connectors may alternate around the circumference of the expandable stent.

In any of the embodiments of fig. 13A-17, the first set of connectors extending from the first axially extending element in the first circumferential direction may extend from the first axially extending element at an axial location different from the axial location at which the second set of connectors extend from the first axially extending element in the second circumferential direction (i.e., the connectors have axially offset ends).

In any of the embodiments of fig. 13A-17, the expandable stent may include a transition region connecting the first axially extending element with the strut, optionally wherein the transition region is considered to be part of the expandable stent. The transition region may also connect the strut with a second axially extending element, the second axially surrounding the blood conduit adjacent the first axially extending element. In any of the stents illustrated in fig. 13A-17, the expandable stent may extend along substantially the entire length of the conduit. In any of the brackets shown in fig. 13A-17, the expandable bracket may extend along less than 50% of the length of the expandable impeller housing. In any of the embodiments of fig. 13A-17, the expandable stent may extend only in the area of the expandable housing where the impeller is disposed.

In any of the embodiments of fig. 13A-17, the expandable impeller housing may include a second expandable bracket axially spaced from the first expandable bracket. The second expandable stent may have an expanded configuration with a second plurality of axially extending elements that extend axially within at least 50% of the length of the second expandable stent, and wherein the second expandable stent may further comprise a plurality of sets of connectors, each set of connectors extending circumferentially between circumferentially adjacent first and second axially extending elements. The second expandable stent may include any of the features set forth in any of the claims or described elsewhere herein. In any of the stents shown in fig. 13A-17, the expandable stent may be unitary, i.e., made from a single piece of starting material.

Fig. 18A and 18B illustrate an exemplary stent 450 that includes a plurality of axially extending elements 452 (eight in this example). The stent 450 includes a proximal stent 460, a central stent 462, and a distal stent 464. In this example, the axially extending element 452 is linear. In this example, the central bracket 462 is connected to the proximal bracket 460 and the distal bracket 464, and in particular, in this example, the central bracket 462 is integral with the proximal bracket 460 and the distal bracket 464. Fig. 18B shows an expanded configuration, and fig. 18A shows a cut plan view of the stent. The axially extending elements 452 marked in fig. 18B are circumferentially adjacent axial elements. Adjacent axially extending elements are connected by a plurality of circumferential connectors 451, in this example, the circumferential connectors 451 have a generally S-configuration or reverse S-configuration, including at least one bend formed therein. As shown, each circumferential connector is circumferentially adjacent to the other circumferential connector, and they together extend around the blood conduit. In this example, circumferentially adjacent circumferential connectors are axially displaced relative to each other as shown. For example, circumferential connector 451' is axially displaced (or axially offset) relative to circumferential connector 451 ". In this case, axial displacement or axial offset refers to proximal end axial offset of the connector, distal end axial offset of the connector, or both proximal end axial offset of the connector and distal end axial offset of the connector. In this example, a section of each axially extending element connects axially displaced adjacent circumferential connectors. For example, a section 453 of one of the axially extending elements 452 connects the circumferential connectors 451' and 451", which creates the axial displacement properties of circumferentially adjacent circumferential connectors. In this example, the distal end of connector 451 "is farther distally than the distal end of a circumferentially adjacent connector 451', as shown. Fig. 18A and 18B also show a first set of a plurality of circumferential connectors having a first axial position and a second set of a plurality of circumferential connectors having a second axial position, wherein the first axial position and the second axial position alternate circumferentially around the blood conduit, as shown.

Fig. 19A and 19B illustrate an exemplary bracket 470. The support 470 includes a plurality of axially extending elements 472, which axially extending elements 472 are piecewise linear, but not linear along the entire support 470 length. The bracket 470 further includes a connector 471 that circumferentially connects circumferentially adjacent axial members 472. Connector 471 includes an axially oriented or directed peak, and in this example may be oriented distally or proximally. The stent 470 includes a proximal stent, a central stent, and a distal stent that are connected, and in this example is unitary, as is the stent in fig. 18A and 18B. The proximal, central and distal stents each comprise a plurality of linear axially extending elements spaced about the blood conduit, wherein adjacent first and second linear axially extending elements are each connected by a circumferential connector having at least one bend formed therein. The circumferential connectors define a plurality of circumferential connectors around the blood conduit, and wherein circumferentially adjacent ones of the plurality of circumferential connectors are axially displaced relative to each other. As in fig. 18A and 19B, the segments 473 (linear in this example) of each of the axially extending elements connect axially displaced circumferentially adjacent circumferential connectors as shown. Fig. 19A and 19B illustrate a first set of a plurality of circumferential connectors having a first axial position, and wherein a second set of the plurality of circumferential connectors has a second axial position, wherein the first axial position and the second axial position alternate circumferentially around the blood conduit. In this embodiment, the proximal, center and distal stents are generally the same configuration (except for the ends of the distal and proximal stents).

The stent 470 further comprises a second region 477 axially adjacent to the first region 476, wherein the second region 477 comprises a plurality of peaks 478, the peaks 478 shown being orthogonally oriented relative to a long axis of a blood vessel (membrane not shown for clarity). In this example, as shown, each of the plurality of peaks 478 is an extension of one of the axially extending elements 472 in the first region 476. The stent 470 further includes a third region 479 axially adjacent to the second region 477, the third region 470 including a second plurality of linear axially extending elements spaced around the blood conduit as shown, and a second plurality of circumferential connectors 471, wherein the second region 477 connects the first region 476 and the third region 479. In this example, this morphology continues along the length of the stent.

Fig. 20A and 20B illustrate an exemplary stent 500, fig. 20B illustrates an expanded configuration, and fig. 20A illustrates a flattened unexpanded configuration. Features shown in fig. 20A and 20B that are the same as features shown in other stents herein may be expressly included in the present embodiment, even if not described herein. The stent 500 includes a proximal stent 510, a central stent 520, and a distal stent 530, the proximal stent 510, central stent 520, and distal stent 530 being integral in this embodiment. In this embodiment, the center stent 520 has a morphology and configuration such that the center stent 520 is less rigid than the proximal stent 510 and the distal stent 530 in response to radially inward forces. The proximal stent 510 may be a proximal impeller stent and the distal stent 530 may be a distal impeller stent, wherein the proximal and distal impellers may be disposed within at least a portion of the proximal and distal stents, respectively. The central stent 520 of stent 500 has a morphology that is different from the morphology in stent sections 510 and 530. In this example, the stent sections 510 and 530 have substantially the same morphology. As shown, the stent 500 includes circumferential connectors in a proximal stent 510, a central stent 520, and a distal stent 530. For example, the proximal stent 510 includes a circumferential connector 512 and the distal stent 530 includes a circumferential connector 532. The circumferential connectors in stent 500 have the same configuration as circumferential connectors 451 in stent 450 in fig. 18A and 18B, and all descriptions thereof are incorporated by reference with these circumferential connectors into all stent sections in stent 500. By way of example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, as described in more detail elsewhere herein. The circumferential connectors also have an S-configuration and a reverse S-configuration, which are described herein with respect to other stents. The center stent 520 in the stent 500 also includes peaks 521 and 521', similar to the peaks 478 in the stent in fig. 19A and 19B. The first plurality of peaks 521 has a first axial position and the second plurality of peaks 521' has a second axial position, which can be clearly seen in fig. 20A. The axial positions alternate circumferentially around the stent, as shown. Peaks 521 and 521' extend from the axially extending member 522 as in the stent of fig. 19A and 19B. In this embodiment, the proximal and distal stents do not include peaks. As shown, the axially extending elements 522 in the central stent section have a width that is greater than the width of the stent in the region of the peaks 521. This difference in width may provide greater flexibility for the peak regions, while the wider axially extending elements provide adequate radial support in the center stent. Any stent section having peaks may be considered a first region and axially adjacent sections having circumferential connectors and axially extending elements may be considered a second region, examples of which are described elsewhere herein. In this embodiment, the axially extending element is linear as shown, but may be curvilinear in other embodiments.

Fig. 21A and 21B illustrate an exemplary stent 550, wherein fig. 21B illustrates an expanded configuration and fig. 21A illustrates a flattened, unexpanded configuration. Features shown in fig. 21A and 21B that are the same as features shown in other stents herein may be expressly included in the present embodiment, even if not described herein. The stent 550 includes a proximal stent 560, a central stent 570, and a distal stent 580, the proximal stent 560, central stent 570, and distal stent 580 being integral in this embodiment. The proximal bracket 560 may be a proximal impeller bracket and the distal bracket 580 may be a distal impeller bracket, wherein the proximal and distal impellers may be disposed within at least a portion of the proximal and distal brackets, respectively. The central support 570 of the support 550 has a morphology that is different from the morphology in the support sections 560 and 580. In this example, the cradle sections 560 and 580 have substantially the same morphology. As shown, stent 550 includes circumferential connectors in proximal stent 560, central stent 570, and distal stent 580. For example, proximal stent 560 includes circumferential connector 562 and distal stent 580 includes circumferential connector 582. The circumferential connectors in the stent 550 have the same configuration as the circumferential connectors 451 in the stent 450 in fig. 18A and 18B, and all descriptions thereof are incorporated into all stent sections in the stent 550 by reference to these circumferential connectors. By way of example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, as described in more detail elsewhere herein. The circumferential connectors also have an S-configuration and a reverse S-configuration, which are described herein with respect to other stents. As shown, the elements 571 in the central stent extend into the proximal and distal stent sections, forming linear axially extending elements in the proximal and distal stents. As shown, the axially extending elements 561 in the proximal stent 560 do not extend into the central stent. Similarly, the axially extending elements 581 in the distal stent 580 do not extend into the central stent, as shown. The element 571 in the central support 570 has a helical configuration as shown. As shown, adjacent elements 571 are connected with connectors 572. The connector 572 may have any feature of any circumferential connector herein, such as an alternating S-configuration and a reverse S-configuration. Fig. 21A shows a flattened, unexpanded configuration, and stent 550 may be formed in the configuration shown in fig. 21B, for example, by twisting the ends relative to one another and disposing the stent in the configuration shown in fig. 21B.

Fig. 22A and 22B illustrate an exemplary stent 600, wherein fig. 22B illustrates an expanded configuration and fig. 22A illustrates a flattened, unexpanded configuration. Features shown in fig. 22A and 22B that are the same as features shown in other stents herein may be expressly included in the present embodiment, even if not described herein. The stent 600 includes a proximal stent 610, a central stent 620, and a distal stent 630, the proximal stent 610, central stent 620, and distal stent 630 being integral in this embodiment. The proximal stent 610 may be a proximal impeller stent and the distal stent 630 may be a distal impeller stent, wherein the proximal and distal impellers may be disposed within at least a portion of the proximal and distal stents, respectively. The central stent 620 of stent 600 has a morphology that is different from the morphology in stent sections 610 and 630. In this example, the stent sections 610 and 630 have substantially the same morphology. As shown, the stent 600 includes circumferential connectors in a proximal stent 610, a central stent 620, and a distal stent 630. For example, the proximal stent 610 includes a circumferential connector 612 and the distal stent 630 includes a circumferential connector 632. The circumferential connectors in the proximal and distal sections of stent 600 have the same configuration as circumferential connectors 451 in stent 450 in fig. 18A and 18B, and all descriptions thereof are incorporated by reference with these circumferential connectors into all stent sections in stent 600. By way of example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which will be described in more detail elsewhere herein, and connect the axially extending elements 611 and 631, respectively. The circumferential connectors also have an S-configuration and a reverse S-configuration, which are described herein with respect to other stents. As shown, axially extending elements 621 in the center stent extend into the proximal and distal stent sections, where elements 621 are linear axially extending elements in the proximal and distal stents and the center stent. As shown, the axially extending elements 611 in the proximal stent 610 do not extend into the central stent. Similarly, as shown, the axially extending elements 631 in the distal stent 630 do not extend into the central stent. As shown, the element 621 in the center mount 620 has an axially extending linear configuration. The center bracket 620 includes axially extending elements 621 connected by a circumferential connector. As shown, the circumferential connectors include a plurality of axially extending elements 624, each axially extending element 624 connecting circumferentially adjacent circumferential connectors 622. When the stent 600 expands to the configuration shown in fig. 22B, the circumferential connectors assume the configuration shown, wherein the elements 624 are no longer extending purely axially such that they form an angle with the long axis of the stent, as shown.

Fig. 23A and 23B illustrate an exemplary stent 650, wherein fig. 23B illustrates an expanded configuration and fig. 23A illustrates a flattened, unexpanded configuration. Features shown in fig. 23A and 23B that are the same as features shown in other stents herein may be expressly included in the present embodiment, even if not described herein. The stent 650 includes a proximal stent 660, a central stent 670, and a distal stent 650, the proximal stent 660, central stent 670, and distal stent 650 being integral in this embodiment. The proximal rack 660 may be a proximal impeller rack and the distal rack 650 may be a distal impeller rack, wherein the proximal and distal impellers may be disposed within at least a portion of the proximal and distal racks, respectively. The central mount 670 of mount 650 has a morphology that is different from the morphology in mount sections 660 and 680. In this example, the stent sections 660 and 680 have substantially the same morphology. As shown, the stent 650 includes circumferential connectors in a proximal stent 660, a central stent 670, and a distal stent 680. For example, the proximal stent 660 includes a circumferential connector 662 and the distal stent 650 includes a circumferential connector 682. The circumferential connectors in the proximal and distal sections of the stent 650 have the same configuration as the circumferential connectors 451 in the stent 450 in fig. 18A and 18B, and all descriptions thereof are incorporated by reference with these circumferential connectors into all stent sections in the stent 650. By way of example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which will be described in more detail elsewhere herein, and connect axially extending elements 661 and 681, respectively. The circumferential connectors also have an S-configuration and a reverse S-configuration, which are described herein with respect to other stents. As shown, axially extending elements 671 in the center stent extend into the proximal and distal stent sections, wherein the elements 671 are linear axially extending elements in the proximal and distal stents and the center stent. As shown, the axially extending elements 661 in the proximal stent 660 do not extend into the central stent. Similarly, as shown, the axially extending element 681 in the distal stent 650 does not extend into the central stent. As shown, the elements 671 in the central mount 670 have an axially extending linear configuration. The center mount 670 includes axially extending elements 671 that are connected by a circumferential connector. As shown, the circumferential connectors include a plurality of axially extending elements 674, each axially extending element 674 connecting circumferentially adjacent circumferential connectors 672. When the stent 650 expands to the configuration shown in fig. 23B, the circumferential connector 672 assumes the configuration shown, wherein the elements 674 are no longer extending purely axially so that they form an angle with the long axis of the stent, as shown. The elements 674 in fig. 23A are formed by removing material axially disposed between axially adjacent elements 674.

Fig. 24A and 24B illustrate an exemplary stent 700, wherein fig. 24B illustrates an expanded configuration and fig. 24A illustrates a flattened, unexpanded configuration. Features shown in fig. 24A and 24B that are the same as features shown in other stents herein may be expressly included in the present embodiment, even if not described herein. For example, the stent 700 is in some respects identical to the stent shown in fig. 19A, 19B, 20A and 20B. The stent 700 includes a proximal stent 710, a central stent 720, and a distal stent 730, the proximal stent 710, the central stent 720, and the distal stent 730 being integral in this embodiment. The proximal stent 710 may be a proximal impeller stent and the distal stent 730 may be a distal impeller stent, wherein the proximal and distal impellers may be disposed within at least a portion of the proximal and distal stents, respectively. The central stent 720 of stent 700 has a morphology that is different from the morphology in stent sections 710 and 730. In this example, the stent sections 710 and 730 have substantially the same morphology. As shown, stent 700 includes circumferential connectors in proximal stent 710, central stent 720, and distal stent 730. For example, proximal stent 710 includes circumferential connector 712 and distal stent 730 includes circumferential connector 732. The circumferential connectors in the proximal and distal sections of stent 700 have the same configuration as circumferential connectors 451 in stent 450 in fig. 18A and 18B, and all descriptions thereof are incorporated by reference with these circumferential connectors into all stent sections in stent 700. By way of example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which will be described in more detail elsewhere herein, and connect the axially extending elements 711 and 731, respectively. The circumferential connectors also have S-configurations and reverse S-configurations that alternate circumferentially around the stent, which is described herein with respect to other stents. The stent 700 includes a plurality of axially extending elements 711, which circumferentially adjacent circumferential connectors are piecewise linear, but do not extend along the entire length of the stent 700. The bracket 700 further comprises a circumferential connector 712 that circumferentially connects circumferentially adjacent axial elements 711. The proximal, central and distal stents respectively comprise a plurality of linear axially extending elements 711, 721 and 731 circumferentially spaced around the respective stent section, wherein adjacent first and second linear axially extending elements are each connected by a circumferential connector 712, 722 and 732 respectively, wherein at least one bend is formed. The circumferential connectors define a plurality of circumferential connectors around the bracket, and wherein circumferentially adjacent ones of the plurality of circumferential connectors are axially displaced relative to each other as shown and described elsewhere herein. As in the case of fig. 18A and 19B, a portion of each of the axially extending elements (linear elements in this example) connects axially displaced circumferentially adjacent circumferential connectors as shown. Fig. 24A and 24B illustrate a first set of a plurality of circumferential connectors having a first axial position, and wherein a second set of the plurality of circumferential connectors has a second axial position, wherein the first axial position and the second axial position alternate circumferentially about the bracket.

The stent 700 also includes a second region axially adjacent to the first region, wherein the second region includes a plurality of peaks 724, the peaks 724 being shown as oriented orthogonally relative to the long axis of the stent 700. In this example, as shown, each of the plurality of peaks 724 is an extension of one of the axially extending elements 721. The stent 700 also includes a third region axially adjacent to the second region, the third region including a second plurality of linear axially extending elements spaced around the stent as shown, and a second plurality of circumferential connectors 722, wherein the second region joins the first region and the third region. In this embodiment, the second region includes a first male section 725 and a second male section 727 connected at a location 729.

Fig. 25A and 25B illustrate an exemplary stent 750, in this example, the stent 750 includes a proximal stent 760, a central stent 770, and a distal stent 780, the proximal stent 760, central stent 770, and distal stent 780 being integral. The stent 750 is similar in several respects to the stent 700 of fig. 24A and 24B, the disclosure of which stent 700 is fully incorporated by reference into the description of fig. 25A and 25B, any of which features may be included in the stent 750. One difference is that the center stent 770 of stent 750 comprises a first region comprising peaks 774, wherein the first region comprises sections 775 and 777 connected at location 779, wherein sections 775 and 777 produce a smoother curvilinear region than sections 725 and 727 in stent 700. Another difference is that stent 750 includes a proximal stent and a distal stent that both include mirrored sections (e.g., sections 763 and 765 as shown in fig. 25B). The mirror image aspect refers to axially adjacent connectors 762 of section 763 that are mirror images relative to connectors 762 in section 765. The same mirror image aspect is shown in the distal stent 780. As shown, the mirrored section in the proximal stent 760 is closer to the central stent 770 than the mirrored section in the distal stent 780. In alternative embodiments, the mirrored section in the distal stent may be closer to the central stent than the mirrored section in the proximal stent. All other aspects of the stent (including axially extending elements and circumferential connectors) are described herein as incorporated by reference into stent 750. Fig. 25B shows a flat expanded configuration, while fig. 25A shows a flat unexpanded configuration.

Fig. 26A and 26B illustrate a stent 800, as shown, the stent 800 includes many of the same features as the stent 750 shown in fig. 25A and 25B. Fig. 26A shows a flattened unexpanded configuration, while fig. 26B shows a transition region 801 of the stent 800 invoked in fig. 26A. The difference between the stents is that in fig. 26A and 26B, the proximal stent 810 includes a mirrored section that is farther from the central stent 820 than the mirrored section in the distal stent, as shown. Fig. 26B shows the transition region between the proximal stent 810 and the central stent 820. The stent 800 includes orthogonally oriented peaks 824, as described elsewhere herein. The stent first region includes sections 825 and 827, and sections 825 and 827 may be identical to sections 775 and 777 in stent 750. Fig. 26B shows that the width of axially extending element 811 is greater than the width of element 821 in the center bracket, as shown. The thickness measurement is into the page in the figure (in the "z" direction), while the width measurement is in the plane of the page shown in the figure. A thickness "t" of the marker element 811 is provided for reference. As shown, the thickness "t" of element 811 is greater than the thickness of element 821 in the central bracket section.

Fig. 27A and 27B illustrate an exemplary bracket 850, the bracket 850 being similar in several respects to the bracket 550 illustrated in fig. 21A and 21B. The mount 850 includes a proximal mount 860, a central mount 870, and a distal mount 880, which may be unitary in this embodiment. The central support 870 of the support 850 includes a helical element 871 in a non-collapsed configuration (fig. 27A) and a wrapped configuration (fig. 27B). In this embodiment and any other embodiments herein, the stent may be manufactured (e.g., including laser cutting of the tubular member) such that the expanded configuration is a configuration in which the stent is laser cut from the tubular member. This is in contrast to any example where the stent is laser cut from a smaller diameter tubular member and then expanded and set into an expanded configuration. In any of the embodiments herein, the laser cut diameter may be equal to the non-collapsed diameter to provide, for example, but not limited to, better concentricity. This may also allow the coating of the membrane to adhere to the struts and have a smoother inner diameter.

The proximal and distal stents 860, 880 have substantially the same configuration, but the proximal and distal stents 860, 880 are circumferentially displaced by a circumferential spacing "CS" (labeled in fig. 27A). Adjacent screw elements 871 are connected by a connector 872. All other similar aspects of other stents herein may be incorporated herein, including by way of example only, the axially offset nature of circumferentially adjacent circumferential connectors in proximal stent 860 and distal stent 880.

Fig. 27A shows exemplary distal struts and proximal struts extending axially from a stent, with only one strut 865 being labeled. In this example, there are four proximal struts and four distal struts. As shown, the struts are tapered and wider at the ends away from the stent, which may increase stability on the impeller as compared to struts having a constant width over their entire length, any pump portion herein may include any number of struts having the same configuration as struts 865.

In any of the embodiments herein, the stent may be cut from a tubular member having an expanded stent diameter. In these embodiments, the tubular member has the same or substantially the same diameter as the desired stent deployment configuration (unsheathed). Alternatively, in any of the embodiments herein, the stent may be cut from a tubular member having a non-expanded stent diameter. In this embodiment, the tubular member has a diameter that is less than the expanded diameter of the stent, and after being cut, the stent may be expanded to be disposed in an expanded deployed configuration.

In any of the embodiments herein, the length of the distal stent may be greater than the length of the proximal stent. In any of the embodiments herein, the length of the distal stent may be less than the length of the proximal stent. In any of the embodiments herein, the distal stent may have a length that is the same as the length of the proximal stent.

In any of the embodiments herein, the length of the central stent may be greater than the length of one or both of the proximal stent and the distal stent.

Any of the different bracket sections herein may be joined with one or more welds and may not be integral with each other.

In any of the embodiments herein, any one or more sections of the stent may have a thickness (measured radially between the inner diameter of the stent and the outer diameter of the stent) that is the same as or different from the thickness of any other section of the stent. For example, the thickness of the stent sections may be reduced by electropolishing one or more sections more than other sections (which may not include electropolishing). Varying the thickness may be in addition to or instead of varying the width, which may allow for more design choices as desired.

In any of the embodiments herein, the axial distance between the proximal and distal stent sections may be 30mm to 50mm, for example 35mm to 45mm.

In any of the embodiments herein, the pump portion may be 40mm to 80mm, such as 50mm to 70mm, such as 55mm to 65cm.

In any embodiment including the first impeller and the second impeller, the axial distance between the impellers may be 40mm to 60mm, for example 45mm to 55mm.

In any of the embodiments herein, the expanded (or non-collapsed) blood conduit may have a diameter of 6mm to 8.5mm, such as 6mm to 8mm, such as 6.5mm to 7.5mm.

In any of the embodiments herein, any impeller may have a diameter of 5mm to 7mm, such as 5.5mm to 6.5mm, when expanded.

Some pump sections herein include a collapsible and expandable blood conduit, and one or more impellers disposed at least partially in the blood conduit when the pump section is in an operational state. In some embodiments herein, the collapsible blood conduit includes a stent that may extend along at least a portion of the length of the blood conduit and provide radial support to the blood conduit. In some embodiments herein, the stent may be integral along the blood conduit. In some embodiments, the different stent sections may not be integral (formed of the same starting material), but the different stent sections may be directly attached or connected to each other (e.g., welded directly together).

In some embodiments, axially adjacent stent sections may not be integral and not connected to each other. Since axially adjacent stent sections are herein independently attached to one or more membranes, axially adjacent stent sections may still be coupled together. In these examples, the central stent section may not be connected to one or both of the distal stent section or the proximal stent section. In some embodiments herein including only a single impeller pump portion, the center carrier section may not be connected to one or both carrier sections that may be axially adjacent to the center carrier section.

Fig. 28A and 28B illustrate an exemplary collapsible blood tubing 900 of a pump portion, shown expanded (not in a collapsed state). The blood tubing 900 includes a collapsible stent that includes a central stent section 902, a proximal stent section 904, and a distal stent section 906. Herein, proximal and distal do not necessarily mean that they are the most distal or proximal-most stent sections, although they may. Proximal and distal in this context generally refer to relative positions with respect to an axially central stent section. In this example, the axial center stent section 902 is not connected to the proximal stent section 904 or the distal stent section 906 and is not integral with the proximal stent section 904 or the distal stent section 906. The proximal, central, and distal stent sections are each individually connected to one or more membrane layers, as described in more detail elsewhere herein.

The pump portion 900 in fig. 28A and 28B may be considered similar to other pump portions herein, such as the pumps shown in fig. 2, 3A-4, 9, as the pump portion may be considered to include a proximal expandable impeller cage and a distal expandable impeller cage, examples of which are described herein. For example, the pump portion 340 in fig. 3A-3D includes an exemplary proximal stent or cage 343 and a distal stent or cage 344. The proximal stent section 904 may be considered similar to the proximal stent 343 and the distal stent section 906 may be considered similar to the distal stent 344. Thus, the pump portion 900 may be considered similar in any other respect to the pump portion 340 described herein while also including a central stent section 902 that is not directly attached to the proximal and distal stent sections. The pump membrane forming the blood tubing may be composed of one or more layers of membrane material, as described in more detail herein.

In the alternative to the pump portion shown in fig. 28A and 28B, the pump portion may not include any cage as that term is used herein, but the central support may still be non-integral and not connected to one or both of the proximal and distal support sections. For example, pump 900 may alternatively exclude a cage having distal struts and proximal struts, similar to the stent shown in fig. 11. Further, the stent in fig. 11 may alternatively include a discontinuity between the central stent section and one or both of the proximal and distal stents such that the central stent is not unitary and is not connected to the proximal and/or distal stent sections. Thus, any stent herein may be modified to include a discontinuity between the central stent section and one or both of the proximal and distal stents such that the central stent is not integral and not connected to the proximal and/or distal stent sections.

Fig. 28A and 28B illustrate a pump section having more than one impeller, but the pump section may include a single impeller, such as a proximal impeller or a distal impeller. If the pump section includes a single impeller, the axial position of the impeller may be different from the positions shown in fig. 28A and 28B. For example, the proximal impeller may be disposed entirely within the blood conduit. The impellers in fig. 28A and 28B are illustrative and may be replaced with any suitable impeller herein or known in the art.

Any of the central stent sections herein may be connected to or integral with one of the distal stent section or the proximal stent section, and may not be integral and not connected to the other of the distal stent section and the proximal stent section.

Any of the central stent sections herein may have a stent configuration that is different from one or both of the proximal and distal stent sections. For example, in the example of fig. 28A and 28B, the central stent section 902 has a different overall configuration than the proximal section 904 and the distal section 906. In fig. 28A and 28B, the proximal and distal stent sections may have the same or similar configuration as, for example, any of the proximal and distal stent sections shown in fig. 13A-13C, 14A and 14B, 15A and 15B, 16, 17, 18A and 18B, 19A and 19B, 20A and 20B, 21A and 21B, 22A and 22B, 23A and 23B, 24A and 24B, 25A and 25B, 26A and 26B, or 27A and 27B, the description of which is incorporated by reference into the examples of fig. 28A and 28B. The proximal and distal stent sections may have the same configuration, a similar configuration, or different overall configurations. In the text, these configurations are compared in their entirety (including repeat sections from proximal end to distal end and overall structure). The examples in fig. 28A and 28B show the same proximal and distal stent sections.

In the alternative to any of the embodiments herein, the central stent section may be connected to or integral with one of the proximal stent and the distal stent, but not the other. For example, referring to fig. 28A, in the alternative, the bracket section 902 may be integral with the bracket section 906 or the bracket section 904 instead of the other or connected to the bracket section 906 or the bracket section 904 instead of the other.

Any stent or stent section herein may be understood as having a proximal end and a distal end. For example, the proximal end 901 and the distal end 903 of the center stent 902, respectively, are shown in fig. 28A and 28B. P in fig. 28A refers to the proximal direction, and D refers to the distal direction. The inflow I and outflow O are also marked. Any other aspect of any of the pump sections herein may be incorporated into the pump section 900, including any alternatives thereof. An exemplary proximal impeller 920 and distal impeller 930 are also shown in fig. 28A and 28B, as are exemplary drive assemblies 940, the drive assemblies 940 being rotationally coupled to a motor (not shown) that drives rotation of one or more impellers.

The pump section herein generally has a central region that is generally more flexible than one or both of the proximal and distal impeller regions, the advantages of which are described elsewhere herein. In general, the central stent section herein is more flexible than the proximal and distal impeller sections. For example, the central stent 902 shown in fig. 28A and 28B may be considered to have a similar configuration to the central stent section shown in fig. 25A-26B (the description of which is fully incorporated by reference), which may provide greater flexibility to the central stent than the proximal and distal stent sections. Furthermore, at least one of the proximal end 901 and the distal end 903 of the central stent section is not connected to an adjacent stent section, which may impart additional flexibility to the blood tubing in the vicinity of the central stent section.

In the example shown in fig. 28A and 28B, the pump portion 900 includes a proximal impeller cage, a bracket portion of the proximal impeller cage defining a proximal bracket section 904. The pump portion 900 also includes a distal impeller cage, with a bracket portion of the distal impeller cage defining a distal bracket section 906. The proximal cage also includes a proximal cage proximal strut 908 and a proximal cage distal strut 910, additional exemplary details of which are described elsewhere herein. The distal cage includes a distal cage proximal strut 912 and a distal cage distal strut 914, additional exemplary details of which are described elsewhere herein. The pump portion 900 may include any suitable features or aspects of any expandable cage described herein.

During pump collapse, one or more cage ends (e.g., bearing housings) may be axially moved relative to the drive assembly 940 or other radially inner component to facilitate collapse, additional exemplary details of which are described elsewhere herein. Further, any of the struts herein may have free ends coupled, connected or integral with a central hub, central assembly or bearing assembly, examples of which are shown and described herein.

Fig. 29A-29E illustrate an exemplary stent 2950, the stent 2950 being similar to the stent 850 illustrated in fig. 27A and 27B, but having a different stent morphology. In this embodiment and any other embodiments herein, the stent 2950 may be manufactured (e.g., including laser cutting of a tubular member) such that the expanded configuration is a configuration in which the stent is laser cut from the tubular member. In this embodiment, the proximal and distal ends of the stent include free ends that include a plurality of free strut ends.

Fig. 29A shows a flattened view of the stent. The stent 2950 includes a proximal stent section 2960, a central stent section 2970, and a distal stent section 2980. The proximal section 2960 may be configured to enclose a proximal impeller, and the distal section 2980 may be configured to enclose a distal impeller. In other embodiments, the stent is configured to enclose only a single impeller, such as a proximal impeller in the proximal section 2960, and no distal impeller in the distal section 2980. In some cases, the proximal impeller and/or the distal impeller have the same diameter and axial length. In some cases, the proximal impeller and/or the distal impeller have different diameters and/or axial lengths. The bracket 2950 may be unitary and may be made from a single piece of material (e.g., metal). For example, the stent 2950 includes a series of axially extending elongate elements 2911 that extend from the proximal section 2960, through the central section 2970, and to the distal section 2980. The first set of elongate elements 2911 form a proximal strut 2952 at the proximal end of the stent 2950. Likewise, the second set of elongate elements 2911 form a distal strut 2951 at the distal end of the stent 2950. The axially extending elongate element 2911 may be connected by a connector element 2912 in the proximal section 2960 and a connector element 2922 in the distal section 2980.

In this example, the proximal and distal sections 2960, 2980 each include ten axially extending elongate elements 2911. This arrangement may provide greater radial stiffness to the stent 2950 than the proximal and distal sections 860, 880 of fig. 27A and 27B, each of the proximal and distal sections 860, 880 comprising eight axially extending elongate elements. Imparting a greater radial stiffness variation may also increase the bending stiffness. Thus, the proximal and distal sections 2960, 2980 of the stent 2950 of fig. 29A-29E may have a greater transverse bending stiffness than the proximal and distal sections 860, 880 of the stent 850 of fig. 27A and 27B. Bending stiffness may refer to the ability of the scaffold 2950 or a portion of the scaffold 2950 to withstand deformation when a lateral force is applied to one side of the scaffold or a portion of the scaffold 2950.

Note that in this case, a greater number of elongated elements 2911 extending in the stent 2950 results in a greater number of proximal struts 2952 and distal struts 2951 than the stent 850 of fig. 27A and 27B. Specifically, the stent 2950 includes five proximal struts 2952 and five distal struts 2951, while the stent 850 includes four proximal struts and four distal struts. This arrangement may provide the scaffold 2950 with greater radial rigidity than the scaffold 850 in this region. In some cases, the one or more proximal struts 2952 and the one or more distal struts 2951 can include cutouts or recesses 2918 (optionally, areas of reduced relative circumferential width) that provide space or accommodation for the presence of one or more sensing elements (e.g., one or more of a pressure sensor and/or a pressure sensor housing) on the central hub of the blood pump assembly.

In the central section 2970 of the stent 2950, the elongate element 2911 may be axially inclined to have a helical or spiral shape that wraps around the center or long axis of the stent 2950. Such a helical or spiral arrangement of elongate elements in the central section may allow the central section 2970 to be laterally more flexible and bendable as compared to the proximal and distal sections 2960, 2980. This aspect may allow the central section 2970 to deflect when a lateral force is applied to one side of the blood conduit, such as when the blood conduit passes through a patient's blood vessel and/or within a chamber of the heart. For example, the central section 2970 may be configured to laterally flex when a lateral force is applied to the distal section 2980 and/or the proximal section 2960. In some cases, as described herein, it may be desirable for the central section 2970 to flex laterally as the blood conduit passes through the ascending aorta and for the central section 2970 to temporarily assume a curved configuration as the blood conduit is positioned through the aortic valve. The helical or spiral-shaped configuration in the central section may allow lateral bending without collapsing the internal lumen of the central section 2970, thereby allowing blood to flow through the central section 2970. Once the lateral bending force is released, the central section 2970 may assume its original straight shape with the proximal and distal sections 2960/2980 axially aligned. In some examples, the scaffold 2950 can be made of a shape memory material (e.g., nitinol), wherein the scaffold 2950 is shaped to an expanded configuration, and the proximal, central, and distal sections 2960, 2970, 2980 are axially aligned (e.g., the central section 2970 is straightened). Accordingly, once the lateral bending force of the rack 2950 is released, the rack 2950 can return to the original shape setting state.

In the example of the stent 2950, the helical or spiral-shaped portions 2971 of the elongate elements 2911 within the central section 2970 are not connected to one another by an intermediate connector (e.g., connector 872 of fig. 27A and 27B). Accordingly, the helical or spiral portions 2971 within the central section 2970 may be circumferentially separated from one another by the struts 2950. This aspect may provide greater lateral flexibility to the central section 2970. Further, the width of the helical portion 2971 of the elongate element may be less than the width of the elongate element 2911 within the proximal and distal sections 2960, 2980. This arrangement may provide greater flexibility to the central section 2970 as compared to the proximal and distal sections 2960, 2980, which may also contribute to the lateral flexibility of the central section 2970. The central section 2970 may be adapted to bend to a greater extent than, or to have a greater extent than, both the proximal section 2960 and the distal section 2980 in response to a lateral force applied to the distal section 2980. When in use, the central section 2970 can be positioned across the aortic valve, and the flexibility of the central section 2970 can help the central section 2970 deform or flex when placed across the valve.

In some cases, the central section 2970 is flexible enough to cause the central section 2970 to assume a curved configuration when the blood conduit is positioned across the valve (e.g., aortic valve) and the central section 2970 is disposed in the position of the valve leaflets. The curved configuration may result in the rotational axis of the proximal impeller being misaligned (e.g., not parallel) with the rotational axis of the distal impeller (e.g., similar to that shown in fig. 4).

The proximal, central, and/or distal sections 2960, 2970, 2980 may have different configurations of structural elements that may provide different stiffness to the proximal, central, and/or distal sections 2960, 2970, 2980. For example, the connector elements 2912 in the proximal section 2960 and the connector elements 2922 in the distal section 2980 are arranged in annular rows about the central axis of the tubular stent to provide radial and/or bending stiffness to the respective sections. In this case, the proximal section 2960 includes more connector elements 2912 (four annular rows) than the distal section 2980 (three annular rows), thereby providing greater radial and/or bending stiffness to the proximal section 2960 relative to the distal section 2980.

The spacing between the stent elements (e.g., connector elements 2912/2922 and elongate element 2911) may also be correlated to the radial and/or bending stiffness of the stent sections. For example, axially adjacent connector elements 2912 may be axially closer to each other in the proximal section 2960 than in the distal section 1980, which may help to impart greater relative stiffness (e.g., radial and/or bending stiffness) in the proximal section 2960. In this example, the proximal section 2960 has a denser stent morphology than the distal section 2980, resulting in the proximal section 2960 having a greater radial and/or bending stiffness than the distal section 2980. For example, the connector elements 2912 that connect axially extending elongate elements 2911 circumferentially within the proximal section 2960 may be separated by a first distance 2934, and the connector elements 2922 that connect axially extending elongate elements 2911 within the distal section 2980 may be separated by a second distance 2936, wherein the first distance 2934 is less than the second distance 2936. This may result in the aperture 2966 between the stent elements within the proximal section 2960 being smaller than the aperture 2968 between the stent elements within the distal section 2980.

For any stent described herein, stent sections having a morphology with a larger cumulative spacing (e.g., spacing between stent elements) area may be referred to as "loosely arranged" and stent sections having a morphology with a smaller cumulative spacing area may be referred to as "tightly arranged". For example, the proximal section 2960 may be characterized as having a more tightly arranged stent morphology than the distal section 2980. A section with a more tightly arranged stent morphology may be associated with a greater radial and/or bending stiffness than a section with a more loosely arranged stent morphology.

In some examples, the vertical spacing 2933 between the elongated elements 2911 may be within a range bounded by any two of the following values: 1mm, 1.5mm, 2mm, 2.5mm, 3.0mm, 3.5mm, 4mm, 4.5mm and 5mm.

In some examples, the first distance 2934 between the connector elements 2912 of the proximal section 2960 may be within a range bounded by any two of the following values: 3.0mm, 3.5mm and 4.0mm.

In some examples, the second distance 2936 between the connector elements 2922 of the distal section 2980 may be within a range bounded by any two of the following values: 4.0mm, 4.5mm and 5.0mm.

The proximal and distal sections 2960, 2980 may have different axial lengths. In this example, the proximal section 2960 may have an axial length 2975 that is greater than the axial length 2977 of the distal section 2980. In some cases, the axial length 2975 of the proximal section 2960 may be about 5% to 20% greater than the axial length 2977 of the distal section 2980. The axial length 2979 of the central section 2970 may be greater than the axial length 2975 of the proximal section 2960 and/or the axial length 2977 of the distal section 2980. The axial length 2975 of the proximal section 2960 may be within a range bounded by any two of the following values: 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm and 25mm. The axial length 2977 of the distal section 2980 may be within a range bounded by any two values: 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm and 16mm. The axial length 2979 of the central section 2970 may be within a range bounded by any two of the following values: 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm and 30mm. The axial length 2961 of the proximal strut 2952 and/or the axial length 2981 of the distal strut 2951 may be within a range bounded by any two values: 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm and 10mm.

In some cases, the axial length 2975 of the proximal section 2960 may be greater than the axial length 2977 of the distal section 2980, based on the different forces that these sections are expected to experience during operation within the patient. For example, the distal region 2967 of the proximal section may experience a higher level of radially inward force than the proximal region 2969 of, for example, the distal section 2980. Having a longer proximal section 2960 may compensate for this expected greater inward radial force at the distal region 2967 of the proximal section 2960 to prevent this region of the stent 2950 from collapsing.

In some examples, the total axial length of the scaffold 2950 and any of the scaffolds described herein can be within a range bounded by any two of the following values: 50mm, 55mm, 60mm, 65mm, 70mm, 75mm and 80mm.

In some cases, it may be beneficial for the proximal section 2960 to be radially stiffer and longer than the distal section 2980. For example, a particular placement of the stent 2950 within the patient's body may cause the proximal section 2960 to experience a greater radially inward force (e.g., bending force) than the distal section 2980. For example, the proximal section 2960 may experience a greater bending force within the ascending aorta than the distal section 2980 within the left ventricle. The stiffer and longer proximal section 2960 may reduce or prevent deformation of the proximal section 2960, thereby preventing the proximal impeller from contacting the wall of the blood conduit and/or maintaining the integrity of the blood conduit lumen so that blood flows through the proximal portion of the stent 2950.

In some cases, the axial length 2979 of the central section 2970 is greater than or less than the axial length 2975 of the proximal section 2960 and/or the axial length 2977 of the distal section 2980. In the example shown, the central section 2970 is greater than the axial length 2975 of the proximal section 2960 and the axial length 2977 of the distal section 2980.

The axially extending elongate element 2911 within the central section 2970 may be angled relative to the longitudinal axis of the bracket 2950. The angle θ of the axially extending elongate element 2911 within the central section 2970 may be non-parallel and non-orthogonal relative to the longitudinal axis of the stent 2950, forming a helical arrangement of the axially extending elongate element 2911 about the central axis of the stent 2950.

The angle θ may be determined based on several factors. For example, the angle θ may be determined based on a desired degree of lateral curvature of the center section 2970. In some examples, the center section 2970 may have a greater lateral flexibility at a greater angle θ and a lesser lateral flexibility at a lesser angle θ.

The angle θ may also be determined based on the expected axial force exerted on the blood tubing as the blood pump passes through the patient's blood vessel/heart and/or as the blood tubing is sheathed and/or unsheathed. For example, it may be desirable for the central section 2970 to be sufficiently axially rigid to at least partially axially deform when such axial force is applied to the blood conduit. In some examples, the central section 2970 may have a greater axial stiffness at a smaller angle θ and a lesser axial stiffness at a greater angle θ.

Another factor determining the angle θ may include the extent to which the blood tubing is stretched as it collapses during its sheathing. The blood tubing may be longer in a collapsed state (e.g., when sheathed) than in an expanded state (e.g., when unsheathed). In some cases, the central hub on the proximal and/or distal side of the stent 2950 may be configured to accommodate changes in length as the blood tubing transitions between the expanded and collapsed states. However, in some cases, it may be desirable to minimize such length variation, or to keep the extent of the length variation within a threshold range. The extent to which the blood tubing can be stretched may be based at least in part on the angle θ. In some examples, a greater angle θ may be associated with a greater degree of elongation when the blood conduit is transitioned to the collapsed state than a lesser angle θ.

In some examples, the angle θ of the axially extending elongated element 2911 within the central section 2970 may be within a range bounded by any two values: 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, and 60 degrees. In some examples, the angle θ may be within a range bounded by any two of the following values: 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, and 45 degrees.

In some cases, the width of the axially extending elongate element 2911 may vary along the length of the stent 2950. In some examples, the width 2927 of the axially extending elongate element 2911 within the central section 2970 is less than the width 2928 of the axially extending elongate element 2911 within the proximal section 2960 and/or the width 2929 of the axially extending elongate element 2911 within the distal section 2980. The axially extending elongate elements 2911 in the proximal and/or distal sections 2960, 2980 may have a greater relative width to provide adequate support for the stent 2950 around the respective impellers. The axially extending elongate elements 2911 in the central section 2970 may have a smaller relative width to provide lateral flexibility of the central section 2970 for lateral bending of the pump, for example, when located within a curved portion of the patient anatomy. The relatively smaller width axially extending elongate elements 2911 in the central section 2970 may alternatively or additionally allow the stent to collapse more easily, thereby reducing the sheathing strain.

Fig. 29B illustrates an exemplary blood tubing 2901, with the stent 2950 in an assembled state and in an expanded configuration. The proximal section 2960 of the bracket 2950 surrounds or encircles at least a portion of the proximal impeller 2920, and the distal section 2980 of the bracket 2950 surrounds at least a portion of the distal impeller 2930. The bracket 2950 also encloses at least a portion of the drive shaft 2959, with the proximal impeller 2920 and the distal impeller 2930 operatively coupled to the portion of the drive shaft 2959, including a central region of the drive shaft extending between the impellers. The proximal struts 2952 may be bent radially inward and coupled to the proximal end hub 2986, and the distal struts 2951 may be bent radially inward and coupled to the distal end hub 2988. In some cases, each of the proximal and distal central hubs 2986, 2988 at least partially houses or is adjacent to a bearing assembly operably coupled to the drive shaft 2959. The drive shaft 2959 may be configured to flex laterally as the bracket flexes laterally and to maintain an operational function (e.g., to rotate the impellers 2920 and 2930) as the drive shaft 2959 flexes.

In the example shown, the membrane 2949 covers the aperture of the stent 2950 to form a blood conduit. In some cases, the membrane 2949 may cover at least a portion or all of the inner and/or outer surfaces of the scaffold 2950. For example, in some cases, the entire stent 2950 (including the inner and outer diameters) may be covered by the membrane 2949. In some cases, the membrane 2949 may not cover the struts 2951/2952. In some cases, the membrane 2949 may cover at least a portion of the struts 2951/2952. The blood tubing may optionally include an inner membrane extending over at least a portion of an inner surface of any of the stents herein. The membrane 2949 may be made of a material flexible enough to allow the blood tubing to expand and collapse. The membrane 2949 may be made of any of the membrane materials described herein (e.g., biocompatible polymer materials).

The membrane 2949 may be formed on the scaffold 2950 using any of a variety of techniques. In some cases, the film 2949 may be applied using a spray technique. In some examples, the film 2949 may be formed in one or more layers. In some cases, the film 2949 is formed by applying heat, pressure, and/or vacuum to the film material.

Fig. 29C shows the proximal impeller region of the blood pump in a collapsed state and encased within an outer sheath 2955. The scaffold 2950 can be configured to be in a higher energy state when in a collapsed state such that a radially inward force, e.g., from the inner wall of the outer sheath 2955, is required to maintain the scaffold in the collapsed state. When the outer sheath 2955 is removed (e.g., by pulling the outer sheath 2955 proximally and/or pushing the blood pump distally), the stent 2950 may relax and transition to a lower energy expanded state. Fig. 29C shows how the connector element 2912 may bend (optionally at the ends of the connector element 2912, which may be relatively more curved than the center linear determination of the connector element 2912, which may facilitate bending at the ends of the connector 2912) to bring the axially extending elongate elements 2911 radially inward and closer together, thereby collapsing the stent 2950. Likewise, as the stent 2950 expands, the connector elements 2912 may relax to their low energy state such that the connector elements 2912 may move radially outward and away from each other. Further, the struts 2952 may transition from a curved shape when the stent 2950 is in the expanded configuration to a more straight shape when the stent 2950 is in the collapsed configuration.

Fig. 29D and 29E show close-up views of the proximal and distal portions, respectively, of the stent 2950. As described above, the width 2928 of the axially extending element 2911 within the proximal section 2960 and/or the width 2929 of the axially extending element 2911 within the distal section 2980 may be greater than the width 2927 of the axially extending element 2911 within the central section 2970. This may help provide greater radial and/or bending stiffness of the proximal and/or distal sections 2960, 2980 relative to the central section 2970. In some embodiments, the width 2928 of the axially extending element 2911 within the proximal section 2960 and/or the width 2929 of the axially extending element 2911 within the distal section 2980 may be within a range defined by any two values: 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm and 0.45mm. In some embodiments, the width 2927 of the axially extending element 2911 within the central section 2970 may be within a range bounded by any two values: 0.15mm, 0.2mm, 0.25mm and 0.3mm. In some embodiments, widths 2928 and/or 2929 may be about 2% to 100% any range of percentages between than width 2927.

The transition between the widths 2928 and/or 2929 and the width 2927 may occur within the transition region 2947 between the central section 2970 and the proximal section 2960 or the distal section 2980. The axially extending element 2911 within the transition region 2947 may have a curved shape such that the axially extending element 2911 may transition from parallel (relative to the central axis of the blood conduit) within the proximal or distal section 2960, 2980 to a helical configuration within the central section 2970. In some embodiments, the radius of curvature 2944 of each axially extending element 2911 within the transition region 2947 may be within a range bounded by any two values: 0.1 inch, 0.2 inch, 0.3 inch, 0.4 inch, and 0.5 inch. In some embodiments, the length of the transition region 2947 along the axially extending element 2911 may be within a range bounded by any two of the following values: 0.10 inches, 0.15 inches, 0.20 inches, and 0.25 inches.

The shape and size of the connector element 2912 (in the proximal section 2960) and/or 2922 (in the distal section 2980) may vary depending on, for example, the desired bending and/or outward expansion force. As described above, the connector elements 2912 and/or 2922 may flex as the stent 2950 transitions from the expanded state to the collapsed state. In the example shown, the connector elements 2912 and 2922 may each have a straight portion 2991 and a curved portion 2992, where they are connected to an axially extending elongated element 2911. Note that in this example, the radius of curvature of the curved portion 2992 of the connector elements 2912 and 2922 is less than the radius of curvature of the connector elements in the example mount 850 of fig. 27A and 27B. In some cases, the connector elements 2912/2922 are arranged circumferentially around the bracket 2950 in a zig-zag configuration.

The angle α between the connector element 2912 in the proximal section 2960 (or the connector element 2922 in the distal section 2980) and the axially extending element 2911 may be in the range of about 30 degrees to 50 degrees. As shown, the row of connector elements 2912 may generally resemble a zig-zag or chevron shape in that the row of connector elements 2912 extends radially or circumferentially around the proximal and/or distal sections. In some embodiments, for example when the angle α between a connector element and an axially extending element is about 45 degrees, adjacent connector elements may be generally orthogonal or perpendicular to another connector element.

In general, stent morphology may be tailored to achieve specific performance characteristics. As described above, the angle θ may be selected to achieve a desired amount of lateral flexibility and axial rigidity of the center section (e.g., 2970). Further, the stent morphology in and around the proximal section (e.g., 2960) and the distal section (e.g., 2980) may at least partially determine the radial and/or bending stiffness of the proximal and distal sections. In one aspect, it may be desirable for the proximal section (e.g., 2960) and the distal section (e.g., 2980) to have a sufficiently high radial stiffness when in the expanded state to withstand the radially inward pressure experienced when the blood pump is operated within the patient's body. Further, it may be desirable for the proximal section (e.g., 2960) and the distal section (e.g., 2980) to have a sufficiently high bending stiffness to withstand deformation when lateral forces are applied to the sides of the stent as the blood conduit passes through the wall of the patient's vessel and/or heart chamber. Such radial and/or bending stiffness may maintain the blood tubing in an expanded state to prevent the impeller from contacting the inner wall of the blood tubing during pump operation. On the other hand, it may be desirable that the proximal section (e.g., 2960) and the distal section (e.g., 2980) be able to assume a collapsed state with a sufficiently small diameter for resheathing without having to apply undue amounts of sheathing force. The ability of the stent to collapse may be at least partially associated with a degree of elastic strain in the stent. In some examples, a higher amount of elastic strain (relative to plastic strain) is associated with a greater ability to compress to a collapsed state without permanently deforming the stent. The stent morphology may be designed to reduce such intrathecal strain. Where the stent is made of a shape memory material, the stent may be heat set at a particular temperature (e.g., body temperature) to have the desired shape and material characteristics. In some cases, one or more computer modeling techniques (e.g., finite element analysis or other modeling analysis) are used to estimate the degree of strain experienced by the stent during use based on stent morphology, materials, and/or other variables.

Fig. 30 illustrates a flattened view of another exemplary stent 3050 that is similar to the stent 2950 illustrated in fig. 29A-29E, but with a different stent morphology variation. Like the stent 2950, the stent 3050 includes a proximal stent section 3060, a central stent section 3070, and a distal stent section 3080, wherein the proximal section 3060 may be configured to at least partially enclose a proximal impeller, and the distal section 3080 may be configured to at least partially enclose a distal impeller. The stent 3050 includes a series of axially extending elongate elements 3011, the axially extending elongate elements 3011 extending from the proximal section 3060, through the central section 3070, and to the distal section 3080. Like the stent 2950, the stent 3050 includes ten axially extending elongate elements 3011.

The various feature sizes of the stent 3050 may be similar to the feature sizes of the stent 2950 of fig. 29A-29E. For example, the angle θ of the axially extending elongate element 3011 in the central section 3070 may be the same as the stent 2950. As with the stent 2950, the width 3027 of the axially extending elongate element 3011 in the central section 3070 may be less than the width 3028 of the axially extending elongate element 3011 in the proximal section 3060 and/or the width 3029 of the axially extending elongate element 3011 in the distal section 3080. The axial length 3061 of the proximal strut 3052 may be the same as the axial length 2961 of the proximal strut 2952, and the axial length 3081 of the distal strut 3051 may be the same as the axial length 2981 of the distal strut 2951. The widths 3027, 3028, and 3029 may be the same as the widths 2927, 2928, and 2929 of the rack 2950, respectively. The radius of curvature of each axially extending element 3011 within the transition region 3047 may be the same as the radius of curvature of the axially extending element 2911 within the transition region 2947 of the stent 2950. The proximal section 3060 may have a greater radial and/or bending stiffness than the distal section 3080.

The stent 3050 of fig. 30 has a different connector element morphology than the stent 2950 of fig. 29A-29E, which may allow the stent 3050 to have reduced sheathing strain compared to the stent 2950. The angle α between the connector element 3012 in the proximal section 3060 (or the connector element 3022 in the distal section 3080) and the axially extending element 3011 is less than the angle α in the mount 2905 of fig. 29A-29E. In some examples, angle α may be in the range of about 10 degrees to 30 degrees. The axial length 3075 of the proximal section 3060 may be substantially the same as the axial length 2975 of the proximal section 2960 of the stent 2905 of fig. 29A-29E. However, due to the smaller angle α, the proximal section 3060 includes three annular rows of connector elements 3012 (as compared to the five annular rows of connector elements 2912 of the bracket 2950) and the distal section 3080 includes two annular rows of connector elements 3022 (as compared to the three annular rows of connector elements 2922 of the bracket 2950). Having fewer annular rows of connector elements 3012/3022 may allow the stent to more easily collapse from the deployed configuration to the collapsed configuration. Further, the length of connector element 3012 is greater than the length of connector element 2912, and the length of connector element 3022 is greater than the length of connector element 2922. Likewise, the first distance 3034 between connector elements 3012 is greater than the first distance 2934 between connector elements 2912, and the second distance 3036 between connector elements 3022 is greater than the second distance 2936 between connector elements 2922.

In some examples, the first distance 3034 between the connector elements 3012 of the proximal section 3060 may be within a range defined by any two of the following values: 5.0mm, 5.5mm, 6.0mm, 6.5mm and 7.0mm.

In some examples, the second distance 3036 between the connector elements 3022 of the distal section 3080 can be within a range defined by any two of the following values: 6.0mm, 6.5mm, 7.0mm, 7.5mm and 8.0mm.

Fig. 31 shows a flattened view of another exemplary stent 3150, the stent 3150 being similar to stent 3050 (fig. 30) but having a different stent morphology. Like the stent 3050, the stent 3150 comprises a proximal stent section 3160, a central stent section 3170, and a distal stent section 3180, wherein the proximal section 3160 may be configured to at least partially enclose a proximal impeller, and the distal section 3180 may be configured to at least partially enclose a (optional) distal impeller. The bracket 3150 includes a series of axially extending elongate elements 3111, the axially extending elongate elements 3111 extending from the proximal section 3160, through the central section 3170, and to the distal section 3180. Like the bracket 3050, the bracket 3150 includes ten axially extending elongate elements 3111.

Various feature sizes of the scaffold 3150 may be similar to the feature sizes of the scaffold 3050. For example, the angle θ of the axially extending elongate element 3111 within the central section 3170 may be the same as the bracket 3050. As with the stent 3050, the width 3127 of the axially extending elongate element 3111 within the central section 3170 may be less than the width 3128 of the axially extending elongate element 3111 within the proximal section 3160 and/or the width 3129 of the axially extending elongate element 3111 within the distal section 3180. The widths 3127, 3128, and 3129 can be the same as the stand 3050. The radius of curvature of each axially extending element 3111 within the transition region 3147 may be the same as the radius of curvature of the bracket 3050. The proximal section 3160 may have a greater radial and/or bending stiffness than the distal section 3180.

The proximal section 3160 of the stent 3150 has a slightly longer axial length 3175 as compared to the axial length 3075 of the proximal section 3060 of the stent 3050 of fig. 30. The longer axial length 3175 may provide greater radial and/or bending stiffness to the proximal section 3160 of the stent 3150 as compared to the proximal section 3060 of the stent 3050. The axial length 3161/3181 of the proximal/distal struts 3152/3151 may be less than the axial length 3061/3081 of the proximal/distal struts 3052/3051 such that the overall axial length of the stent 3150 is substantially the same as the stent 3050. Furthermore, the proximal section 3160 of the stent 3150 has a different connector element morphology than the proximal section 3060 of the stent 3050. For example, the proximal section 3160 has four annular rows of connector elements 3112 as compared to three annular rows of connector elements 3012 of the stent 3050. This increased number of connector elements may allow for more structural support around the proximal impeller.

Fig. 32A and 32B illustrate another exemplary bracket 3250. Fig. 32A shows a flattened view of the bracket 3250. The bracket 3250 is similar to the bracket 3150 shown in fig. 31. The angle θ of the axially extending elongated element 3211 within the central section 3270 may be the same as the bracket 3150. The angle α between the connector element 3212 in the proximal section 3260 (or the connector element 3222 in the distal section 3280) and the axially extending element 3211 may be the same as the stent 3150. As with the stent 3150, the axial length 3279 of the central section 3270 can be longer than the axial length 3275 of the proximal section 3260 and/or the axial length 3277 of the distal section 3280. As with the stent 3150, the axial length 3275 of the proximal section 3260 can be longer than the axial length 3277 of the distal section 3280. As with the stent 3150, the width 3227 of the axially extending elongate element 3211 within the central section 3270 may be less than the width 3228 of the axially extending elongate element 3211 within the proximal section 3260 and/or the width 3229 of the axially extending elongate element 3211 within the distal section 3280. The width 3228 of the axially extending elongated element 3211 in the proximal section 3160 and the width 3229 of the axially extending elongated element 3211 in the distal section 3280 may be the same as those in the stent 3150. The radius of curvature of each axially extending element 3211 within the transition region 3247 may be the same as the radius of curvature of the stent 3050. The proximal section 3260 can have a greater radial and/or bending stiffness than the distal section 3280.

One of the differences between the bracket 3250 and the bracket 3150 (fig. 31) is the number of struts. In contrast to the five proximal struts 3150 and the five distal struts 3152 of the stent 3150, the stent 3250 includes eight proximal struts 3252 and eight distal struts 3251. In addition, the width 3299 of the proximal and distal struts 3252, 3251 is less than the width of the proximal and distal struts of the stent 3150. The smaller strut width can accommodate a greater number of struts 3252/3251 in the stent 3250. In some examples, the width of the proximal and distal struts 3252/3251 of the stent 3250 is about 10% -90% less than the width of the struts 3152/3151 of the stent 3150. The smaller strut width may also change the radial and/or bending stiffness and/or the sheathing strain characteristics of the stent 3250.

Another difference between the stent 3250 and the stent 3150 (fig. 31) is the stent morphology of the proximal section 3260 and the distal section 3280. In addition to the axially extending elongate member 3211, the proximal section 3260 of the stent 3250 includes a secondary axially extending member 3298, which secondary axially extending member 3298 is shorter than the axially extending elongate member 3211 and does not extend into the central section 3270. Further, the proximal section 3260 and distal section 3280 of the stent 3250 have a greater number of connector elements 3221/3222 than the stent 3150. Furthermore, the distal section 3280 comprises three annular rows of connecting elements 3222, as compared to two annular rows of connecting elements 3122 in the distal section 3180 of the stent 3150. The width 3228 of the axially extending elongate elements 3211 within the proximal and distal sections 3260, 3280 may be less than the width of the axially extending elongate elements within the proximal and distal sections of the stent 3150 (e.g., less than 10% -90%) to accommodate a greater number of elements. This difference in the number and width of the axially extending elongate elements 3211 and the number of connecting elements 3222 may result in different radial and/or bending stiffness and/or sheathing strain characteristics of the stent 3250.

Another difference between the bracket 3250 and the bracket 3150 (fig. 31) is the nature of the axially extending elongate member 3211 within the central section 3270. The bracket 3250 includes eight axially extending elongate elements 3211 within the central section 3270, while the bracket 3150 includes ten axially extending elongate elements 3111 within the central section 3170. In addition, the width 3227 of the axially extending elongate member 3211 in the bracket 3250 is less than the width 3127 of the axially extending elongate member 3111 in the bracket 3150. The lesser number and lesser width of the axially extending elongate elements 3211 within the central section 3270 may be associated with greater lateral flexibility of the central section 3270 as compared to the scaffold 3150.

The axial length of the proximal, central, and/or distal sections 3260, 3270, 3280 may be slightly different from the axial length of the proximal, central, and/or distal sections of the stent 3150 (fig. 31) to accommodate different numbers and arrangements of struts, axially extending elongate elements, and connector elements. In some cases, the length 3275 of the proximal section 3260 of the stent 3250 is less than the length 3175 of the proximal section 3160 of the stent 3150. In some cases, the length 3279 of the central section 3270 of the scaffold 3250 is greater than the length 3179 of the central section 3170 of the scaffold 3150. In some cases, the length 3277 of the distal section 3280 of the stent 3250 is the same as the length 3177 of the central section 3180 of the stent 3150.

Fig. 32B shows the stent 3250 in a radially expanded state. In fig. 32B, struts 3252 and 3251 are shown in a straightened state (e.g., prior to shape setting and coupling to the central hub). When coupled to a central hub (which may include a bearing assembly), struts 3252 and 3251 may flex radially inward and connect to the central hub, as shown in fig. 29B.

Fig. 33A-33B illustrate another exemplary support 3350. Fig. 33A shows a flattened view of the stent 3350, and fig. 33B shows a three-dimensional view of the stent in an expanded state. The stent 3350 may be similar to the stent described previously and include many of the same elements as the stent described previously, including a proximal section 3360, a central section 3370, and a distal section 3380. One of the differences between the stent 3350 and the stents described previously is the number of struts. The stent 3350 includes ten proximal struts 3352 and five distal struts 3351. It should be understood that in other embodiments, the number of distal struts and proximal struts may be different. Generally, in this embodiment, the stent may have twice as many proximal struts as distal struts (i.e., eight proximal struts and four distal struts, ten proximal struts and five distal struts, twelve proximal struts and six distal struts, etc.). Further, the proximal strut 3352 may have a width that is greater than the width of the distal strut 3351. In one embodiment, as shown, the distal strut 3351 has a width generally the same as the width of the axially extending elongate element 3311.

Since the stent 3350 has a different number of proximal struts than distal struts, there are more connector elements 3312 in the proximal section 3360 than connector elements 3322 in the distal section 3380. As shown in fig. 33A, the proximal section 3360 may have twenty connector elements 3312 in each annular row of connector elements, as compared to only ten connector elements 3322 in each annular row of connector elements in the distal section 3380. Typically, the number of connector elements 3312 in the proximal section 3360 is twice the number of proximal struts 3352. Similarly, the number of connector elements 3322 in distal section 3380 is twice the number of distal struts 3351.

Further still referring to fig. 33A, the central section may include ten axially extending elongated elements 3311. In general, the stent 3350 may include the same number of axially extending elongate elements 3311 as the proximal struts 3352. Thus, the illustrated example includes ten proximal struts 3352 and ten axially extending elongate elements 3311. In the proximal section 3360, an axially extending elongate element 3311 may extend in a distal direction from each distally facing vertex 3382 of the distal-most annular row of connector elements 3312. Conversely, in the distal section 3380, an axially extending elongate element 3311 may extend in a proximal direction from each proximally facing vertex 3384 and each distally facing vertex 3386 of the annular row of connector elements 3322.

The proximal section 3360 of the stent 3350 may also include a secondary axially extending element 3398, which secondary axially extending element 3398 is shorter than the axially extending elongate element 3211 and does not extend into the central section 3270. However, the distal section 3380 does not include an auxiliary axially extending elongate element because the distal section includes only a single annular row of connector elements 3322. Typically, when more than one annular row of connector elements is used, the auxiliary axially extending elongate elements are included only in the distal or proximal section.

Another difference between the stent 3350 and the previously described stents is the number of annular rows of connector elements in the proximal and distal sections. Referring to fig. 33A-33B, the proximal section 3360 may include two annular rows of connector elements 3312. The proximal section 3360 of the support 3350 surrounds or encircles at least a portion of the proximal impeller (not shown). Conversely, the distal section 3380 may include a single annular row of connector elements 3322. In the embodiment of fig. 33A-33B, there is no distal impeller located in the distal section, so the pump is designed and configured to operate as a single (proximal) impeller device. However, it should be understood that a distal impeller may be included if desired.

Fig. 34 shows another exemplary stent 3450 with some variations from the stent 3350 of fig. 33A-33B. One difference is that the distal section 3480 of the stent 3450 comprises two annular rows of connector elements 3422 as compared to only a single annular row of connector elements in the embodiment of fig. 33A-33B. The additional annular rows of connector elements provide additional rigidity in the distal section 3480 as compared to the distal section 3380 of the stent 3350. Since the distal section comprises two annular rows, both the distal section and the proximal section may comprise auxiliary axially extending elements 3498 extending between the annular rows of connector elements. Although the mount 3450 includes two annular rows of connector elements in both the proximal and distal sections 3460, 3480, in an exemplary embodiment, only a single proximal impeller is housed in the proximal section and no distal impeller is housed in the distal section. However, it should be understood that the bracket may be used to house the distal and proximal impellers, if desired.

Since the mount 3450 has two annular rows of connector elements in both the proximal and distal sections, the configuration of the structural elements in the proximal section can define a set of holes 3466 and the configuration of the structural elements in the distal section can define a set of holes 3468. The configuration of the structural elements defining the set of holes may include a connector element and a secondary axially extending element in each section. Because the distal section has fewer distal struts and thus fewer connector elements, the aperture 3468 of the distal section may be smaller than the aperture of the proximal section.

Another difference between the stent 3450 and the stent 3350 is that the distal struts 3451 may have at least a portion that is wider than the proximal struts 3452. As a result, the width of the axially extending elongate element 3411 may taper from a first width to a second (thinner) width in the taper region 3488. In some embodiments, as shown in fig. 34, the distal strut 3451 may further include a taper 3490 from a first width to a second (thinner) width. The portion of the distal strut distal from the taper 3490 may be designed and configured to be overmolded or fitted into a distal hub (not shown).

Claims

1. An intravascular blood pump comprising:

a collapsible blood conduit defining an internal lumen for movement of blood therethrough, the collapsible blood conduit comprising:

a proximal section defined by at least two annular rows of connector elements arranged about a central axis of the collapsible blood conduit;

a distal section defined by at least one annular row of connector elements arranged about the central axis of the collapsible blood conduit;

a central section axially disposed between the distal section and the proximal section, the central section comprising a plurality of axially extending elongate elements arranged in a helical configuration; and

A proximal impeller disposed within at least a portion of the proximal section.

2. The intravascular blood pump of claim 1, wherein the proximal, central, and distal stent sections are coupled together (optionally, the proximal, central, and distal stent sections are unitary).

3. The intravascular blood pump of any one of claims 1-2, wherein the central section is relatively flexible as compared to the distal section and the proximal section such that in response to a lateral force on the blood conduit in the distal impeller section, the blood conduit deforms and assumes a configuration in which the central section has a higher degree of curvature than the proximal section and the distal section.

4. An intravascular blood pump according to any one of claims 1-3, wherein the central section comprises at least one of a material or a structure such that: the central section is less resistant to collapse than the proximal and distal sections when a rotational force is applied to the distal end of the blood conduit.

5. The intravascular blood pump of any one of claims 1-4, wherein at least a portion of the proximal section and the distal section are devoid of a helical stent morphology.

6. The intravascular blood pump of claim 1, wherein the axially extending elongate element extends between at least two annular rows of connector elements in the proximal section.

7. The intravascular blood pump of claim 1, wherein the distal section is defined by at least two annular rows of connector elements arranged about the central axis of the collapsible blood conduit.

8. The intravascular blood pump of claim 7, wherein the axially extending elongate element extends between at least two annular rows of connector elements in the distal section.

9. The intravascular blood pump of claim 1, wherein the proximal section is defined by at least four annular rows of connector elements arranged about the central axis of the collapsible blood conduit.

10. The intravascular blood pump of claim 1, wherein the connector elements in each annular row are in a zig-zag configuration.

11. The intravascular blood pump of any one of claims 1-10, wherein an angle between the connector element and the axially extending elongate element ranges from about 10 degrees to 50 degrees.

12. The intravascular blood pump of any one of claims 1-10, wherein an angle between the connector element and the axially extending elongate element ranges from about 10 degrees to 30 degrees.

13. The intravascular blood pump of any one of claims 1-10, wherein an angle between the connector element and the axially extending elongate element ranges from about 30 degrees to 50 degrees.

14. The intravascular blood pump of any one of claims 1-13, wherein the stent has an axial length ranging from about 50mm to about 80mm.

15. The intravascular blood pump of any one of claims 1-14, wherein the proximal section has a greater lateral bending stiffness than the distal section.

16. The intravascular blood pump of any one of claims 1-15, wherein the collapsible blood conduit includes a stent configured to transition between a collapsed state and an expanded state, wherein the stent has a diameter in the expanded state ranging from 5.0mm to 10mm and a diameter in the collapsed state ranging from 2.5mm to 4.5mm.

17. The intravascular blood pump of any one of claims 1-16, further comprising a plurality of proximal struts extending proximally from the proximal section.

18. The intravascular blood pump of claim 17, further comprising a plurality of distal struts extending distally from the distal section.

19. The intravascular blood pump of claim 18, wherein the number of the plurality of proximal struts is twice the number of the plurality of distal struts.

20. The intravascular blood pump of claim 18, wherein the intravascular blood pump includes ten proximal struts and five distal struts.

21. The intravascular blood pump of claim 18, wherein the distal strut has a width that is greater than a width of the proximal strut.

22. The intravascular blood pump of claim 21, wherein the axially extending elongate element increases in width near the distal section.

23. An intravascular blood pump comprising:

a collapsible blood conduit defining an internal lumen for movement of blood therethrough, the collapsible blood conduit comprising a collapsible stent;

a plurality of proximal struts extending proximally from the blood conduit;

a plurality of distal struts extending distally from the blood conduit, wherein the number of the plurality of proximal struts is twice the number of the plurality of distal struts; and

a proximal impeller disposed at least partially within the blood conduit.

24. The intravascular blood pump of claim 23, wherein the plurality of proximal struts extend proximally from a proximal section of the intravascular blood pump.

25. The intravascular blood pump of claim 24, wherein the proximal impeller is at least partially disposed within the proximal section.

26. The intravascular blood pump of claim 23, wherein the plurality of distal struts extend distally from a distal section of the intravascular blood pump.

27. The intravascular blood pump of claim 23, wherein the plurality of proximal struts comprises ten proximal struts, and wherein the plurality of distal struts comprises five distal struts.

28. The intravascular blood pump of any one of claims 23-27, wherein a width of the plurality of proximal struts is less than a width of the plurality of distal struts.

29. The intravascular blood pump of claim 24, wherein the proximal section is defined by at least two annular rows of connector elements arranged about a central axis of the collapsible blood conduit.

30. The intravascular blood pump of claim 26, wherein the distal section is defined by at least one annular row of connector elements arranged about a central axis of the collapsible blood conduit.

31. The intravascular blood pump of any one of claims 23-30, wherein the stent comprises a central section disposed between a proximal section and a distal section, wherein the central section comprises axially extending elongate elements arranged in a helical configuration.

32. An intravascular blood pump according to any one of claims 29 or 30, wherein the connector elements in each annular row are arranged in a zig-zag formation.

33. The intravascular blood pump of any one of claims 23-32, wherein the stent has an axial length ranging from about 50mm to about 80mm.

34. The intravascular blood pump of claim 24, wherein the proximal section has a greater transverse bending stiffness than distal and central sections of the collapsible stent.

35. The intravascular blood pump of any one of claims 23-34, wherein the stent is configured to transition between a collapsed state and an expanded state, wherein the stent ranges in diameter from 5.0mm to 10mm in the expanded state and ranges in diameter from 2.5mm to 4.5mm in the collapsed state.

36. A tubular stent for an intravascular blood pump, the tubular stent comprising:

a proximal section configured to house a proximal impeller;

a distal section; and

a central section between the proximal section and the distal section, the central section having a plurality of elongate elements extending axially in a helical arrangement and being unconnected to each other within the central section.

37. The tubular stent of claim 36, wherein the proximal section and the distal section comprise connector elements that connect the elongate elements within the proximal section and the distal section.

38. The tubular stent of claims 36-37, wherein the elongate element is parallel to a central axis of the tubular stent within the proximal section.

39. The tubular stent of any one of claims 36-38, wherein the elongate element is parallel to a central axis of the tubular stent within the distal section.

40. The tubular stent of any one of claims 36-39, wherein the central section has greater lateral flexibility than the proximal section and the distal section.

41. The tubular stent of any one of claims 36-40, wherein the proximal section and the distal section each have a greater radial stiffness than the central section.

42. The tubular stent of any one of claims 36-41, wherein the tubular stent comprises a plurality of struts that curve radially inward and are configured to connect to a central hub of the intravascular blood pump.

43. The tubular stent of any one of claims 36-42, wherein the tubular stent is configured to transition between a radially expanded state and a radially collapsed state.

44. The tubular hanger of any one of claims 36-43, wherein the central section has a greater axial length than each of the first impeller section and the second impeller section.

45. The tubular stent of any one of claims 36-44, wherein the elongate elements are connected by one or more annular rows of connector elements within the proximal section.

46. The tubular stent of any one of claims 36-45, wherein the elongate elements are connected by at least two annular rows of connector elements within the proximal section.

47. The tubular stent of any one of claims 45-46, wherein the connector elements in each annular row are arranged in a zig-zag configuration.

48. The tubular stent of any one of claims 36-47, further comprising a membrane covering at least a portion of an inner surface and/or an outer surface of the tubular stent.

49. The tubular stent of any one of claims 36-48, wherein the elongate element extends axially through the proximal section, the central section, and the distal section.

50. The tubular stent of any one of claims 36-49, wherein laterally bending the central section causes the proximal section to be axially misaligned relative to the distal section.

51. The tubular stent of any one of claims 36-50, wherein the proximal section has a greater radial and lateral bending stiffness than the distal section.

52. The tubular stent of any one of claims 36-51, wherein the tubular stent is configured to transition between a collapsed state and an expanded state, wherein the tubular stent has a diameter in the expanded state ranging from 5.0mm to 10mm and a diameter in the collapsed state ranging from 2.5mm to 4.5mm.

53. The intravascular blood pump of claim 36, wherein the helical arrangement of elongate elements is configured to laterally flex the central section upon application of a lateral force applied to the tubular stent.

54. A tubular stent for an intravascular blood pump, the tubular stent comprising:

a proximal section configured to at least partially house a proximal impeller, the proximal section having a first stent morphology; and

a distal section having a second stent morphology, wherein the first stent morphology is more closely arranged than the second stent morphology.

55. The tubular stent of claim 54, wherein the first stent morphology is associated with a first stiffness and the second stent morphology is associated with a second stiffness, wherein the first stiffness is greater than the second stiffness.

56. The tubular stent of claim 55, wherein the first stiffness and the second stiffness comprise one or more of a radial stiffness and a bending stiffness.

57. The tubular stent of any one of claims 54-56, further comprising a central section between the proximal section and the distal section, the central section having a more loosely disposed stent morphology than each of the proximal section and the distal section.

58. The tubular stent of claim 57, wherein the central section comprises a plurality of elongate elements that extend axially in a helical arrangement and are unconnected to each other within the central section, wherein the helical arrangement of elongate elements is configured to laterally bend the central section upon application of a lateral force applied to the tubular stent.

59. The tubular stent of any one of claims 54-58, wherein the tubular stent is configured to transition between a collapsed state and an expanded state, wherein the tubular stent has a diameter in the expanded state ranging from 5.0mm to 10mm and a diameter in the collapsed state ranging from 2.5mm to 4.5mm.

60. An intravascular blood pump comprising:

a collapsible blood conduit having an internal lumen for passage of blood therethrough, the collapsible blood conduit comprising a stent positioned and configured to provide radial support for the blood conduit, the stent comprising a proximal section comprising a first configuration of structural elements defining a first set of apertures and a distal section comprising a second configuration of structural elements defining a second set of apertures, wherein the first set of apertures is smaller than the second set of apertures; and

a proximal impeller disposed within at least a portion of the proximal section of the stent.

61. The intravascular blood pump of claim 60, wherein the proximal section has a greater axial length than the distal section.

62. The intravascular blood pump of claims 60-61, wherein the first configuration of structural elements defining the first set of holes includes a plurality of axially extending elongate elements and a plurality of connector elements extending radially between the plurality of axially extending elongate elements.

63. The intravascular blood pump of claims 60-61, wherein the second shape of the structural elements defining the second set of holes includes a plurality of axially extending elongate elements and a plurality of connector elements extending radially between the plurality of axially extending elongate elements.

64. The intravascular blood pump of claim 62, wherein the plurality of connector elements in the proximal section form a plurality of annular rows of connector elements.

65. The intravascular blood pump of claim 63, wherein the plurality of connector elements in the distal section form a plurality of annular rows of connector elements.

66. The intravascular blood pump of claims 64-65, wherein each annular row of connector elements is formed in a zig-zag configuration.

67. The intravascular blood pump of any one of claims 60-66, wherein the stent comprises a central section between the proximal section and the distal section.

68. The intravascular blood pump of claim 67, wherein the proximal section has a greater radial stiffness than the central section.

69. The endovascular blood pump of claim 67 wherein the distal section has a greater radial stiffness than the central section.

70. The intravascular blood pump of claim 67, wherein the central section is configured to flex laterally when a lateral force is applied to the distal section.

71. The endovascular blood pump of claim 67 wherein the stent comprises an elongate element extending axially within the proximal section, the central section and the distal section.

72. The intravascular blood pump of claim 71, wherein a portion of the elongate element within the proximal section is wider than a portion of the elongate element within the central section.

73. The intravascular blood pump of claim 71, wherein a portion of the elongate element within the distal section is wider than a portion of the elongate element within the central section.

74. The intravascular blood pump of claim 71, wherein circumferentially adjacent elongate elements are circumferentially connected by connector elements within the proximal and distal sections.

75. The endovascular blood pump of claim 74 wherein the proximal section comprises more connector elements than the distal section.

76. The endovascular blood pump of claim 74 wherein the connector element is configured to flex to move circumferentially adjacent elongate elements closer to one another when the stent transitions from the expanded state to the collapsed state.

77. An intravascular blood pump according to claim 71, wherein the elongate elements are unconnected to each other within the central section.

78. The intravascular blood pump of claim 71, wherein the portion of the elongate element within the central section is arranged in a spiral configuration about a central axis of the stent.

79. The endovascular pump defined in any one of claims 60-78, wherein the stent is configured to transition between a collapsed state and an expanded state.

80. The endovascular blood pump of any one of claims 60-79 further comprising a drive shaft operatively coupled to the proximal impeller, wherein the stent surrounds at least a portion of the drive shaft.

81. The intravascular blood pump of any one of claims 60-80, wherein the proximal impeller is configured to collapse with the collapsible blood conduit.

82. The intravascular blood pump of any one of claims 60-81, wherein the stent comprises an elongate element extending axially along a length of the stent, wherein the axially extending elongate elements are connected by one or more annular rows of connector elements within the proximal section.

83. The intravascular blood pump of claim 82, wherein the elongate elements are connected by three annular rows of connector elements within the proximal section (e.g., fig. 30).

84. The intravascular blood pump of claim 82, wherein the elongate elements are connected by four annular rows of connector elements within the proximal section (e.g., fig. 31).

85. The intravascular blood pump of claim 82, wherein the elongate elements are connected by five annular rows of connector elements within the proximal section (e.g., fig. 29A-29E).

86. The intravascular blood pump of claim 82, wherein the connector elements in each annular row are in a zig-zag configuration.

87. The endovascular blood pump of any one of claims 60-86 wherein the stent comprises an elongate element extending axially along the length of the stent, wherein the axially extending elongate element is connected by a first set of annular rows of connector elements in the proximal section and a second set of annular rows of connector elements in the distal section, wherein the first set has a greater number of annular rows of connector elements than the second set.

88. The endovascular blood pump of any one of claims 60-87 wherein the stent comprises an elongate member extending axially along the length of the stent and a connector member connecting the elongate member, wherein the angle between the connector member and the elongate member is in the range of from about 10 degrees to 50 degrees.

89. The intravascular blood pump of claim 88, wherein the angle between the connector element and the elongate element ranges from about 10 degrees to 30 degrees (e.g., fig. 30 and 31).

90. The intravascular blood pump of claim 88, wherein the angle between the connector element and the elongate element ranges from about 30 degrees to 50 degrees (e.g., fig. 29A-29E).

91. The endovascular blood pump of any one of claims 60-90 wherein the stent has an axial length in the range of from about 50mm to about 80mm.

92. The endovascular blood pump of any one of claims 60-91 wherein the proximal section has a greater transverse bending stiffness than the distal section.

93. The endovascular blood pump of any one of claims 60-92 wherein the blood conduit is configured to transition between a collapsed state and an expanded state, wherein the stent has a diameter in the expanded state in the range of from 5.0mm to 10mm and a diameter in the collapsed state in the range of from 2.5mm to 4.5mm.

94. A method of using an intravascular blood pump, the method comprising:

delivering the intravascular blood pump in a collapsed state toward a heart;

expanding a stent of the intravascular blood pump in at least a portion of a heart, the expanded stent providing radial support for a blood conduit defining an internal lumen, wherein a proximal section of the stent includes a first set of holes smaller than a second set of holes in a distal section of the stent; and

A proximal impeller disposed within at least a portion of the proximal section of the stent is rotated and blood is pumped through the internal lumen of the blood conduit.

95. The method of claim 94, further comprising expanding the proximal impeller and the distal impeller within the stent.

96. The method of claims 94-95, the proximal section having a greater axial length than the distal section.

97. The method of any one of claims 94-96, further comprising positioning the intravascular blood pump within at least a portion of a heart such that when the stent expands, the proximal section of the stent provides more radial support to the blood conduit than the distal section of the stent.

98. The method of any of claims 94-96, wherein the stent comprises a central section between the proximal section and the distal section, the method further comprising positioning the intravascular blood pump within at least a portion of the heart such that lateral forces applied to the central portion cause the central portion to flex laterally more than the proximal section and laterally more than the distal section.

99. The method of any of claims 94-98, wherein the stent comprises an elongate element extending axially within the proximal section and the distal section, wherein expanding the stent comprises moving the elongate elements radially away from each other.

100. The method of any of claims 94-99, further comprising collapsing the stent such that the elongate elements move radially inward toward each other.

101. The method of any of claims 94-100, wherein the expanding comprises positioning a central stent section at a location of an aortic valve leaflet, positioning at least a portion of the distal section in a left ventricle, and positioning at least a portion of the proximal section in an ascending aorta, wherein the central stent has flexibility such that when positioned at a location of an aortic valve leaflet, the central section assumes a configuration having a higher degree of curvature than the proximal section and the distal section.

102. The method of any of claims 94-101, wherein the proximal section has a greater transverse bending stiffness than the distal section.

103. The method of any of claims 94-102, wherein the scaffold, when expanded, has a diameter in the range of 5.0mm to 10 mm.

104. The method of any one of claims 94-103, further comprising collapsing the stent to position the stent within a sheath, wherein the stent, when collapsed, has a diameter in the range of 2.5mm to 4.5 mm.