WO2021026473A1

WO2021026473A1 - Catheter blood pumps and collapsible pump housings

Info

Publication number: WO2021026473A1
Application number: PCT/US2020/045443
Authority: WO
Inventors: Michael CALOMENI; Brian D. Brandt; Daniel Hildebrand; Greg Hamel
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-07
Filing date: 2020-08-07
Publication date: 2021-02-11
Anticipated expiration: 2022-02-07
Also published as: EP4010046A1; US20210038786A1; EP4010046A4; US12465748B2

Abstract

Catheter blood pumps that include an expandable pump portion. The pump portions include a collapsible blood conduit that defines a blood lumen. The collapsible blood conduits include a collapsible scaffold adapted to provide radial support to the blood conduit. The pump portion also includes one or more impellers.

Description

CATHETER BLOOD PUMPS AND COLLAPSIBLE PUMP HOUSINGS

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Prov. App. No. 62/884,089, filed August 7, 2019, the entire disclosure of which is incorporated by reference herein for all purposes.

INCORPORATION BY REFERENCE

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

BACKGROUND

[0003] Patients with heart disease can have severely compromised ability to drive blood flow through the heart and vasculature, presenting for example substantial risks during corrective procedures such as balloon angioplasty and stent delivery. There is a need for ways to improve the volume or stability of cardiac outflow for these patients, especially during corrective procedures.

[0004] Intra-aortic balloon pumps (IABP) are commonly used to support circulatory function, such as treating heart failure patients. Use of IABPs is common for treatment of heart failure patients, such as supporting a patient during high-risk percutaneous coronary intervention (HRPCI), stabilizing patient blood flow after cardiogenic shock, treating a patient associated with acute myocardial infarction (AMI) or treating decompensated heart failure. Such circulatory support may be used alone or in with pharmacological treatment.

[0005] An IABP commonly works by being placed within the aorta and being inflated and deflated in counterpulsation fashion with the heart contractions, and one of the functions is to attempt to provide additive support to the circulatory system.

[0006] More recently, minimally-invasive rotary blood pumps have been developed that can be inserted into the body in connection with the cardiovascular system, such as pumping arterial blood from the left ventricle into the aorta to add to the native blood pumping ability of the left side of the patient’s heart. Another known method is to pump venous blood from the right ventricle to the pulmonary artery to add to the native blood pumping ability of the right side of the patient’s heart. An overall goal is to reduce the workload on the patient’s heart muscle to stabilize the patient, such as during a medical procedure that may put additional stress on the heart, to stabilize the patient prior to heart transplant, or for continuing support of the patient. [0007] The smallest rotary blood pumps currently available can be percutaneously inserted into the vasculature of a patient through an access sheath, thereby not requiring surgical intervention, or through a vascular access graft. A description of this type of device is a percutaneously- inserted ventricular support device.

[0008] There is a need to provide additional improvements to the field of ventricular support devices and similar blood pumps for treating compromised cardiac blood flow.

SUMMARY OF THE DISCLOSURE

[0009] One aspect of the disclosure is a catheter blood pump. The blood pump may include an expandable pump portion extending distally relative to a catheter. The pump portion may include an impeller housing that includes an expandable blood conduit defining a blood lumen. The expandable blood conduit may include a scaffold that provides radial support to the blood conduit.

[0010] In any embodiment of this aspect, the scaffold may include one or more of a proximal scaffold, a distal scaffold, or a central scaffold disposed between a proximal scaffold and a distal scaffold.

[0011] In any embodiment of this aspect, a central scaffold may be less stiff in response to a radially inward force than one or both of a proximal scaffold and a distal scaffold.

[0012] In any embodiment of this aspect, a proximal scaffold may be a proximal impeller scaffold.

[0013] In any embodiment of this aspect, a distal scaffold may be a distal impeller scaffold. [0014] In any embodiment of this aspect, the one or more scaffold sections may be coupled to a membrane, the membrane at least partially defining the blood lumen.

[0015] In any embodiment of this aspect, a proximal impeller may disposed at least partially within the proximal scaffold and a distal impeller may be disposed at least partially within a distal scaffold.

[0016] In any embodiment of this aspect, a central scaffold may be connected with at least one of the proximal impeller scaffold and the distal impeller scaffold, optionally unitarily connected to one or both.

[0017] In any embodiment of this aspect, a central scaffold may be attached to a proximal impeller scaffold and to a distal impeller scaffold, optionally with welds. [0018] In any embodiment of this aspect, a central scaffold may have a configuration that is different than the proximal impeller scaffold and the distal impeller scaffold.

[0019] In any embodiment of this aspect, a proximal impeller scaffold and a distal impeller scaffold may have the same or substantially the same configuration. A dimension of a first feature of a proximal impeller scaffold may be different than a corresponding feature of the distal impeller scaffold.

[0020] In any embodiment of this aspect, a proximal impeller scaffold and a distal impeller scaffold may have different configurations.

[0021] In any embodiment of this aspect, a distal impeller scaffold may have a length that is greater than a length of a proximal impeller scaffold.

[0022] In any embodiment of this aspect, a distal impeller may have a length that is less than a length of a proximal impeller.

[0023] In any embodiment of this aspect, a width dimension of a central scaffold axially extending element may be less than a width dimension of a proximal impeller scaffold axially extending element. A central scaffold linear element may be axially linear. A central scaffold linear element may be helically linear. Proximal impeller scaffold linear elements may be axially linear.

[0024] In any embodiment of this aspect, at least one of the proximal impeller scaffold and the distal impeller scaffold may comprise a plurality of axially extending elements (optionally linear) spaced apart around the blood conduit. First and second adjacent axially extending elements may each be connected by a circumferential connector having at least one bend formed therein, the circumferential connectors defining a plurality of circumferential connectors around the blood conduit. Circumferentially adjacent circumferential connectors of the plurality of circumferential connectors may be displaced axially relative to one another, and wherein each one of the linear axially extending elements connects adjacent circumferential connectors that are axially displaced. A first group of a plurality of circumferential connectors may have a first axial position, and wherein a second group of the plurality of circumferential connectors may have a second axial position, wherein the first and second axial positions alternate circumferentially around the blood conduit.

[0025] In any embodiment of this aspect, at least one of a proximal impeller scaffold and a distal impeller scaffold may comprise a second plurality of circumferential connectors that are mirrored with a first plurality of circumferential connectors.

[0026] In any embodiment of this aspect, a length of a proximal impeller scaffold may be less than a length of a distal impeller scaffold. A length of a distal impeller may be less than a length of a proximal impeller. A proximal impeller may extend proximally out of the blood conduit. [0027] In any embodiment of this aspect, a central scaffold may include a plurality of helical elements having a helical configuration between a proximal scaffold and a distal scaffold. Adjacent helical elements of the plurality of helical elements may be connected by a plurality of connectors. A plurality of these connectors may comprise an inflection point where the connectors transitions from convex to concave. The helical elements may be an extension of a linear axial element in at least one of the proximal scaffold or the distal scaffold. Linear axial elements in a proximal and a distal scaffold that extend from a first helical element may not be circumferentially aligned.

[0028] In any embodiment of this aspect, a distal scaffold may be circumferentially offset relative to a proximal scaffold, optionally between one and ninety degrees relative to a proximal scaffold.

[0029] In any embodiment of this aspect, first circumferential members in a distal scaffold may be axially closer together than corresponding second circumferential members in a proximal scaffold.

BRIEF DESCRIPTION OF THE DRAWINGS3

[0030] Figure 1 is a side view of an exemplary expandable pump portion that includes an expandable impeller housing that includes a scaffold and blood conduit, and a plurality of impellers.

[0031] Figure 2 is a side view of an exemplary expandable pump portion that includes an expandable impeller housing, a blood conduit, a plurality of impellers, and a plurality of expandable scaffolds sections or support members.

[0032] Figures 3A, 3B, 3C and 3D illustrate an exemplary expandable pump portion that includes a blood conduit, a plurality of impellers, and a plurality of expandable scaffold sections or support members.

[0033] Figure 4 illustrates an exemplary target location of an expandable pump portion, the pump portion including a blood conduit, a plurality of expandable scaffold sections or support members, and a plurality of impellers.

[0034] Figure 5 illustrates an exemplary pump portion including an expandable impeller housing, a blood conduit, and a plurality of impellers.

[0035] Figure 6A illustrates at least a portion of an exemplary catheter blood pump that includes a pump portion, wherein at least two different impellers can be rotated at different speeds.

[0036] Figure 6B illustrates at least a portion of an exemplary catheter blood pump that includes a pump portion, where at least two different impellers can be rotated at different speeds. [0037] Figure 6C illustrates at least a portion of an exemplary catheter blood pump that includes a pump portion with at least two impellers having different pitches.

[0038] Figure 7 illustrates a portion of an exemplary catheter blood pump that includes a pump portion.

[0039] Figure 8 illustrates an exemplary expandable pump portion including a plurality of expandable impellers, including one or more bends formed therein between adjacent impellers. [0040] Figure 9 illustrates an exemplary expandable pump portion comprising a plurality of impellers and a blood conduit.

[0041] Figure 10 illustrates an exemplary scaffold design and exemplary struts.

[0042] Figures 11 illustrate an exemplary scaffold design and exemplary struts.

[0043] Figures 12A-12F illustrate an exemplary sequence of steps that may be performed to deploy an exemplary pump portion of a catheter blood pump.

[0044] Figures 13 A and 13B illustrate exemplary portions of an expandable pump portion. [0045] Figure 13C illustrates a scaffold from figures 13 A and 13B shown in a flattened and non- expanded configuration, as well as optional distal and proximal struts extending axially therefrom.

[0046] Figure 14A illustrates an exemplary expanded scaffold that may be part of any of the expandable pump portions herein.

[0047] Figure 14B illustrates the scaffold and struts from figure 14A in a flattened and non- expanded configuration.

[0048] Figure 15A illustrates an exemplary expanded scaffold that may be part of any of the expandable pump portions herein.

[0049] Figure 15B illustrates the scaffold and struts from figure 15A in a flattened and non- expanded configuration.

[0050] Figure 16 illustrates an exemplary scaffold and optionally coupled struts in a flattened and non-expanded configuration.

[0051] Figure 17 illustrates an exemplary scaffold and optionally coupled struts in a flattened and non-expanded configuration.

[0052] Figure 18A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0053] Figure 18B illustrates the scaffold from figure 18A in an expanded configuration.

[0054] Figure 19A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0055] Figure 19B illustrates the scaffold from figure 19A in an expanded configuration. [0056] Figure 20A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0057] Figure 20B illustrates the scaffold from figure 20A in an expanded configuration. [0058] Figure 21A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0059] Figure 21B illustrates the scaffold from figure 21A in an expanded configuration. [0060] Figure 22A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0061] Figure 22B illustrates the scaffold from figure 22A in an expanded configuration. [0062] Figure 23A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0063] Figure 23B illustrates the scaffold from figure 23A in an expanded configuration. [0064] Figure 24A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0065] Figure 24B illustrates the scaffold from figure 24A in an expanded configuration. [0066] Figure 25A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0067] Figure 25B illustrates the scaffold from figure 25A in an flattened expanded configuration.

[0068] Figure 26A illustrates an exemplary scaffold in a flattened and non-expanded configuration.

[0069] Figure 26B highlights an exemplary section of the scaffold shown in figure 26A. [0070] Figure 27A illustrates an exemplary scaffold in a flattened and non-collapsed configuration.

[0071] Figure 27B illustrates the scaffold from figure 27A in a non-collapsed configuration.

DETAILED DESCRIPTION

[0072] The present disclosure is related to medical devices, systems, and methods of use and manufacture. 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 physiologic vessel, wherein the distal pump portion includes one or more components that act upon fluid. For example, pump portions herein may include one or more rotating members that when rotated, can facilitate the movement of a fluid such as blood. [0073] Any of the disclosure herein relating to an aspect of a system, device, or method of use can be incorporated with any other suitable disclosure herein. For example, a figure describing only one aspect of a device or method can be included with other embodiments even if that is not specifically stated in a description of one or both parts of the disclosure. It is thus understood that combinations of different portions of this disclosure are included herein.

[0074] Figure 1 is a side view illustrating a distal portion of an exemplary catheter blood pump, including pump portion 1600, wherein pump portion 1600 includes proximal impeller 1606 and distal impeller 1616, both of which are in operable communication with drive cable 1612. Pump portion 1600 is in an expanded configuration in Figure 1, but is adapted to be collapsed to a delivery configuration so that it can be delivered with a lower profile. The impellers can be attached to drive mechanism 1612 (e.g., a drive cable). Drive mechanism 1612 is in operable communication with an external motor, not shown, and extends through elongate shaft 1610. The phrases “pump portion” and “working portion” (or derivatives thereof) may be used herein interchangeably unless indicated to the contrary. For example without limitation, “pump portion” 1600 can also be referred to herein as a “working portion.”

[0075] Pump portion 1600 also includes expandable member or expandable scaffold 1602, which in this embodiment has a proximal end 1620 that extends further proximally than a proximal end of proximal impeller 1606, and a distal end 1608 that extends further distally than a distal end 1614 of distal impeller 1616. Expandable members may also be referred to herein as expandable scaffolds or scaffold sections. Expandable scaffold 1602 is disposed radially outside of the impellers along the axial length of the impellers. Expandable scaffold 1602 can be constructed in a manner and made from materials similar to many types of expandable structures that are known in the medical arts to be able to collapsed and expanded, examples of which are provided herein. Examples of suitable materials include, but are not limited to, polyurethane, polyurethane elastomers, metallic alloys, etc.

[0076] Pump portion 1600 also includes blood conduit 1604, which is coupled to and supported by expandable member 1602, has a length L, and extends axially between the impellers. Conduit 1604 creates and provides a fluid lumen between the two impellers. When in use, fluid moves through the lumen defined by conduit 1604. The conduits herein may be non-permeable, or they may be semi-permeable, or even porous as long as they still define a lumen. The conduits herein are also flexible, unless otherwise indicated. The conduits herein extend completely around (i.e., 360 degrees) at least a portion of the pump portion. In pump portion 1600, the conduit extends completely around expandable member 1602, but does not extend all the way to the proximal end 1602 or distal end 1608 of expandable member 1602. The structure of the expandable member creates at least one inlet aperture to allow for inflow “I,” and at least one outflow aperture to allow for outflow “O.” Conduit 1604 improves impeller pumping dynamics, compared to pump portions without a conduit. As described herein, expandable members or scaffolds may also be considered to be a part of the blood conduit generally, which together define a blood lumen. In these instances the scaffold and material supported by the scaffold may be referred to herein as an expandable impeller housing or housing.

[0077] Expandable member 1602 may have a variety of constructions, and made from a variety of materials. For example, expandable member 1602 may be formed similar to expandable stents or stent-like devices, or any other example provided herein. For example without limitation, expandable member 1602 could have an open-braided construction, such as a 24-end braid, although more or fewer braid wires could be used. Exemplary materials for the expandable member as well as the struts herein include nitinol, cobalt alloys, and polymers, although other materials could be used. Expandable member 1602 has an expanded configuration, as shown, in which the outer dimension (measured orthogonally relative a longitudinal axis of the working portion) of the expandable member is greater in at least a region where it is disposed radially outside of the impellers than in a central region 1622 of the expandable member that extends axially between the impeller. Drive mechanism 1612 is co-axial with the longitudinal axis in this embodiment. In use, the central region can be placed across a valve, such as an aortic valve. In some embodiments, expandable member 1602 is adapted and constructed to expand to an outermost dimension of 12-24F (4.0-8.0mm) where the impellers are axially within the expandable member, and to an outermost dimension of 10-20F (3.3-6.7mm) in central region 1622 between the impellers. The smaller central region outer dimension can reduce forces acting on the valve, which can reduce or minimize damage to the valve. The larger dimensions of the expandable member in the regions of the impellers can help stabilize the working portion axially when in use. Expandable member 1602 has a general dumbbell configuration. Expandable member 1602 has an outer configuration that tapers as it transitions from the impeller regions to central region 1622, and again tapers at the distal and proximal ends of expandable member 1602.

[0078] Expandable member 1602 has a proximal end 1620 that is coupled to shaft 1610, and a distal end 1608 that is coupled to distal tip 1624. The impellers and drive mechanisml612 rotate within the expandable member and conduit assembly. Drive mechanism 1612 is axially stabilized with respect to distal tip 1624, but is free to rotate with respect to tip 1624.

[0079] In some embodiments, expandable member 1602 can be collapsed by pulling tension from end-to-end on the expandable member. This may include linear motion (such as, for example without limitation, 5-20mm of travel) to axially extend expandable member 1602 to a collapsed configuration with collapsed outer dimension(s). Expandable member 1602 can also be collapsed by pushing an outer shaft such as a sheath over the expandable member/conduit assembly, causing the expandable member and conduit to collapse towards their collapsed delivery configuration.

[0080] Impellers 1606 and 1616 are also adapted and constructed such that one or more blades will stretch or radially compress to a reduced outermost dimension (measured orthogonally to the longitudinal axis of the working portion). For example without limitation, any of the impellers herein can include one or more blades made from a plastic formulation with spring characteristics, such as any of the impellers described in U.S. Pat. No. 7,393,181, the disclosure of which is incorporated by reference herein for all purposes and can be incorporated into embodiments herein unless this disclosure indicates to the contrary. Alternatively, for example, one or more collapsible impellers can comprise a superelastic wire frame, with polymer or other material that acts as a webbing across the wire frame, such as those described in U.S. Pat. No. 6,533,716, the disclosure of which is incorporated by reference herein for all purposes.

[0081] The inflow and/or outflow configurations of working portion 1600 can be mostly axial in nature.

[0082] Exemplary sheathing and unsheathing techniques and concepts to collapse and expand medical devices are known, such as, for example, those described and shown in U.S. Pat. No. 7,841,976 or U.S. Pat. No. 8,052,749, the disclosures of which are incorporated by reference herein.

[0083] Figure 2 is a side view illustrating a deployed configuration (shown extracorporally) of a distal portion of an exemplary embodiment of a catheter blood pump. Exemplary blood pump 1100 includes working portion 1104 (which as set forth herein may also be referred to herein as a pump portion) and an elongate portion 1106 extending from working portion 1104. Elongate portion 1106 can extend to a more proximal region of the system, not shown for clarity, and that can include, for example, a motor. Working portion 1104 includes first expandable scaffold or member 1108 and second expandable scaffold or member 1110, axially spaced apart along a longitudinal axis LA of working portion 1104. First scaffold 1108 and second scaffold 1110 (and any other separate scaffolds herein) may also be referenced as part of a common scaffold and referred to herein as scaffold sections. Spaced axially in this context refers to the entire first expandable member being axially spaced from the entire second expandable member along a longitudinal axis LA of working portion 1104. A first end 1122 of first expandable member 1108 is axially spaced from a first end 1124 of second expandable member 1110.

[0084] First and second expandable members 1108 and 1110 generally each include a plurality of elongate segments disposed relative to one another to define a plurality of apertures 1130, only one of which is labeled in the second expandable member 1110. The expandable members can have a wide variety of configurations and can be constructed in a wide variety of ways, such as any of the configurations or constructions in, for example without limitation, U.S. Pat. No. 7,841,976, or the tube in 6,533,716, which is described as a self-expanding metal endoprosthetic material. For example, without limitation, one or both of the expandable members can have a braided construction or can be at least partially formed by laser cutting a tubular element.

[0085] Working portion 1104 also includes blood conduit 1112 that is coupled to first expandable member 1108 and to second expandable member 1110, and extends axially in between first expandable member 1108 and second expandable member 1110 in the deployed configuration. A central region 1113 of conduit 1112 spans an axial distance 1132 where the working portion is void of first and second expandable members 1108 and 1110. Central region 1113 can be considered to be axially in between the expandable members. Distal end 1126 of conduit 1112 does not extend as far distally as a distal end 1125 of second expandable member 1110, and proximal end of conduit 1128 does not extend as far proximally as proximal end 1121 of first expandable member 1108.

[0086] When the disclosure herein refers to a blood conduit being coupled to an expandable scaffold or member, the term coupled in this context does not require that the conduit be directly attached to the expandable member so that conduit physically contacts the expandable member. Even if not directly attached, however, the term coupled in this context refers to the conduit and the expandable member being joined together such that as the expandable member expands or collapses, the conduit also begins to transition to a different configuration and/or size. Coupled in this context therefore refers to conduits that will move when the expandable member to which it is coupled transitions between expanded and collapsed configurations.

[0087] Any of the blood conduits herein can be deformable to some extent. For example, conduit 1112 includes elongate member 1120 that can be made of one or more materials that allow the central region 1113 of conduit to deform to some extent radially inward (towards LA) in response to, for example and when in use, forces from valve tissue (e.g., leaflets) or a replacement valve as working portion 1104 is deployed towards the configuration shown in Figure 2. The conduit may be stretched tightly between the expandable members in some embodiments. The conduit may alternatively be designed with a looseness that causes a greater degree of compliance. This can be desirable when the working portion is disposed across fragile structures such as an aortic valve, which may allow the valve to compress the conduit in a way that minimizes point stresses in the valve. In some embodiments, the conduit may include a membrane attached to the proximal and distal expandable members. Exemplary materials that can be used for any conduits herein include, without limitations, polyurethane rubber, silicone rubber, acrylic rubber, expanded polytetrafluoroethylene, polyethylene, polyethylene terephthalate, including any combination thereof.

[0088] Any of the conduits herein can have a thickness of, for example, .5 - 20 thousandths of an inch (thou), such as 1-15 thou, or 1.5 to 15 thou, 1.5 to 10 thou, or 2 to 10 thou.

[0089] Any of the blood conduits herein, or at least a portion of the conduit, can be impermeable to blood. In Figure 2, working portion 1104 includes a lumen that extends from distal end 1126 of conduit 1112 and extends to proximal end 1128 of conduit 1112. The lumen is defined by conduit 1112 in central region 1113, but can be thought of being defined by both the conduit and portions of the expandable members in regions axially adjacent to central region 1113. In this embodiment, however, it is the conduit material that causes the lumen to exist and prevents blood from passing through the conduit.

[0090] Any of the conduits herein that are secured to one or more expandable members can be, unless indicated to the contrary, secured so that the conduit is disposed radially outside of one or more expandable members, radially inside of one or more expandable members, or both, and the expandable member can be impregnated with the conduit material.

[0091] The proximal and distal expandable scaffolds or members help maintain the blood conduit in an open configuration to create the lumen, while each also creates a working environment for an impeller, described below. Each of the expandable scaffolds, when in the deployed configuration, is maintained in a spaced relationship relative to a respective impeller, which allows the impeller to rotate within the expandable member without contacting the expandable member. Working portion 1104 includes first impeller 1116 and second impeller 1118, with first impeller 1116 disposed radially within first expandable member 1108 and second impeller 1118 disposed radially within second expandable member 1110. In this embodiment, the two impellers even though they are distinct and separate impellers, are in operable 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, impellers 1116 and 1118 are axially spaced apart along longitudinal axis LA, just as are the expandable members 1108 and 1110 are axially spaced apart.

[0092] Impellers 1116 and 1118 are also axially within the ends of expandable members 1108 and 1110, respectively (in addition to being radially within expandable members 1108 and 1110). The impellers herein can be considered to be axially within an expandable member even if the expandable member includes struts extending from a central region of the expandable member towards a longitudinal axis of the working portion (e.g., tapering struts in a side view). In Figure 2, second expandable member 1110 extends from first end 1124 (proximal end) to second end 1125 (distal end). [0093] In Figure 2, a distal portion of impeller 1118 extends distally beyond distal end 1126 of conduit 1112, and a proximal portion of impeller 1116 extends proximally beyond proximal end 1128 of conduit 1112. In this figure, portions of each impeller are axially within the conduit in this deployed configuration.

[0094] In the exemplary embodiment shown in Figure 2, impellers 1116 and 1118 are in operable communication with a common drive mechanism 1117, and in this embodiment, the impellers are each coupled to drive mechanism 1117, which extends through shaft 1119 and working portion 1104. Drive mechanism 1117 can be, for example, an elongate drive cable, which when rotated causes the impellers to rotate. In this example, as shown, drive mechanism 1117 extends to and is axially fixed relative to distal tip 1114, although it is adapted to rotate relative to distal tip 1114 when actuated. Thus, in this embodiment, the impellers and drive mechanism 1117 rotate together when the drive mechanism is rotated. Any number of known mechanisms can be used to rotate drive mechanism, such as with a motor (e.g., an external motor).

[0095] The expandable members and the conduit are not in rotational operable communication with the impellers and the drive mechanism. In this embodiment, proximal end 1121 of proximal expandable member 1108 is coupled to shaft 1119, which may be a shaft of elongate portion 1106 (e.g., an outer catheter shaft). Distal end 1122 of proximal expandable member 1108 is coupled to central tubular member 1133, through which drive mechanism 1117 extends. Central tubular member 1133 extends distally from proximal expandable member 1108 within conduit 1112 and is also coupled to proximal end 1124 of distal expandable member 1110.

Drive mechanism 1117 thus rotates within and relative to central tubular member 1133. Central tubular member 1133 extends axially from proximal expandable member 1108 to distal expandable member 1110. Distal end 1125 of distal expandable member 1110 is coupled to distal tip 1114, as shown. Drive mechanism 1117 is adapted to rotate relative to tip 1114, but is axially fixed relative to tip 1114.

[0096] Working portion 1104 is adapted and configured to be collapsed to a smaller profile than its deployed configuration (which is shown in Figure 2). This allows it to be delivered using a lower profile delivery device (smaller French size) than would be required if none of working portion 1104 was collapsible. Even if not specifically stated herein, any of the expandable members and impellers may be adapted and configured to be collapsible to some extent to a smaller delivery configuration.

[0097] The working portions herein can be collapsed to a collapsed delivery configuration using conventional techniques, such as with an outer sheath that is movable relative to the working portion (e.g., by axially moving one or both of the sheath and working portion). For example without limitation, any of the systems, devices, or methods shown in the following references may be used to facilitate the collapse of a working portions herein: U.S. Pat. No. 7841,976 or U.S. Pat. No. 8,052,749, the disclosures of which are incorporated by reference herein for all purposes.

[0098] Figures 3A-3D show an exemplary pump portion that is similar in some ways to the pump portion shown in Figure 2. Pump portion 340 is similar to pump portion 1104 in that in includes two expandable members axially spaced from one another when the pump portion is expanded, and a conduit extending between the two expandable members. Figure 3A is a perspective view, Figure 3B is a side sectional view, and Figures 3C and 3D are close-up side sectional views of sections of the view in Figure 3B.

[0099] Pump portion 340 includes proximal impeller 341 and distal impeller 342, which are coupled to and in operational communication with a drive cable, which defines therein a lumen. The lumen can be sized to accommodate a guidewire, which can be used for delivery of the working portion to the desired location. The drive cable, in this embodiment, includes first section 362 (e.g., wound material), second section 348 (e.g., tubular member) to which proximal impeller 341 is coupled, third section 360 (e.g., wound material), and fourth section 365 (e.g., tubular material) to which distal impeller 342 is coupled. The drive cable sections all have the same inner diameter, so that lumen has a constant inner diameter. The drive cable sections can be secured to each other using known attachment techniques. A distal end of fourth section 365 extends to a distal region of the working portion, allowing the working portion to be, for example, advanced over a guidewire for positioning the working portion. In this embodiment the second and fourth sections can be stiffer than first and third sections. For example, second and fourth can be tubular and first and third sections can be wound material to impart less stiffness.

[0100] Pump portion 340 includes proximal expandable scaffold 343 and distal expandable scaffold 344, each of which extends radially outside of one of the impellers. The expandable scaffolds have distal and proximal ends that also extend axially beyond distal and proximal ends of the impellers, which can be seen in Figures 3B-3D. Coupled to the two expandable scaffolds is blood conduit 356, which has a proximal end 353 and a distal end 352. The two expandable scaffolds each include a plurality of proximal struts and a plurality of distal struts. The proximal struts in proximal expandable scaffold 343 extend to and are secured to shaft section 345, which is coupled to bearing 361, through which the drive cable extends and is configured and sized to rotate. The distal struts of proximal expandable scaffold 343 extend to and are secured to a proximal region (to a proximal end in this case) of central tubular member 346, which is disposed axially in between the expandable members. The proximal end of central tubular member 346 is coupled to bearing 349, as shown in Figure 3C, through which the drive cable extends and rotates. The proximal struts extend axially from distal expandable scaffold 344 to and are secured to a distal region (to a distal end in this case) of central tubular member 346. Bearing 350 is also coupled to the distal region of central tubular member 346, as is shown in Figure 3D. The drive cable extends through and rotates relative to bearing 350. Distal struts extend from the distal expandable scaffold extend to and are secured to shaft section 347 (see Fig. 3A), which can be considered part of the distal tip. Shaft section 347 is coupled to bearing 351 (see Fig. 3D), through which the drive cable extends and rotates relative to. The distal tip also includes bearing 366 (see Figure 3D), which can be a thrust bearing. Working portion 340 can be similar to or the same in some aspects to working portion 1104, even if not explicitly included in the description. In this embodiment, conduit 356 extends at least as far as ends of the impeller, unlike in working portion 1104. Either embodiment can be modified so that the conduit extends to a position as set forth in the other embodiment. In some embodiments, section 360 can be a tubular section instead of wound.

[0101] 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 an impeller may extend beyond an end of the fluid lumen in either the proximal or distal direction. In some embodiments, a portion of an impeller that extends outside of the fluid lumen is a proximal portion of the impeller, and includes a proximal end (e.g., see the proximal impeller in Figure 2). In some embodiments, the portion of the impeller that extends outside of the fluid lumen is a distal portion of the impeller, and includes a distal end (e.g., see the distal impeller in Figure 2). When the disclosure herein refers to impellers that extend outside of the fluid lumen (or beyond an end), it is meant to refer to relative axial positions of the components, which can be most easily seen in side views or top views, such as in Figure 2.

[0102] A second impeller at another end of the fluid lumen may not, however, extend beyond the fluid lumen. For example, an illustrative alternative design can include a proximal impeller that extends proximally beyond a proximal end of the fluid lumen (like the proximal impeller in Figure 2), and the fluid lumen does not extend distally beyond a distal end of a distal impeller (like in Figure 3B). Alternatively, a distal end of a distal impeller can extend distally beyond a distal end of the fluid lumen, but a proximal end of a proximal impeller does not extend proximally beyond a proximal end of the fluid lumen. In any of the pump portions herein, none of the impellers may extend beyond ends of the fluid lumen.

[0103] While specific exemplary locations may be shown herein, the fluid pumps may be able to be used in a variety of locations within a body. Some exemplary locations for placement include placement in the vicinity of an aortic valve or pulmonary valve, such as spanning the valve and positioned on one or both sides of the valve, and in the case of an aortic valve, optionally including a portion positioned in the ascending aorta. In some other embodiments, for example, the pumps may be, in use, positioned further downstream, such as being disposed in a descending aorta.

[0104] Figure 4 illustrates an exemplary placement of pump portion 1104 from catheter blood pump 1000 from Figure 2. Once difference shown in Figure 4 is that the conduit extends at least as far as the ends of the impellers, like in Figures 3A-3D. Figure 4 shows pump portion 1104 in a deployed configuration, positioned in place across an aortic valve. Pump portion 1104 can be delivered as shown via, for example without limitation, femoral artery access (a known access procedure). While not shown for clarity, system 1000 can also include an outer sheath or shaft in which working portion 1104 is disposed during delivery to a location near an aortic valve. The sheath or shaft can be moved proximally (towards the ascending aorta “AA” and away from left ventricle “LV”) to allow for deployment and expansion of working portion 1104. For example, the sheath can be withdrawn to allow for expansion of second expandable scaffold 1110, with continued proximal movement allowing first expandable scaffold 1108 to expand.

[0105] In this embodiment, second expandable scaffold 1110 has been expanded and positioned in a deployed configuration such that distal end 1125 is in the left ventricle “LV,” and distal to aortic valve leaflets “VL,” as well as distal to the annulus. Proximal end 1124 has also been positioned distal to leaflets VL, but in some methods proximal end 1124 may extend slightly axially within the leaflets 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 within the left ventricle. This is also an example of a method in which at least half of second impeller 1118 is positioned within the left ventricle, and also an embodiment in which the entire second impeller 1118 is positioned within the left ventricle.

[0106] Continued retraction of an outer shaft or sheath (and/or distal movement of working end 1104 relative to an outer sheath or shaft) continues to release conduit 1112, until central region 1113 is released and deployed. The expansion of expandable scaffolds 1108 and 1110 causes blood conduit 1112 to assume a more open configuration, as shown in Figure 4. Thus, while in this embodiment conduit 1112 does not have the same self-expanding properties as the expandable scaffolds, the conduit will assume a deployed, more open configuration when the working end is deployed. At least a portion of central region 1113 of conduit 1112 is positioned at an aortic valve coaptation region and engages leaflets. In Figures 3, there is a short length of central region 1113 that extends distally beyond the leaflets VL, but at least some portion of central region 1113 is axially within the leaflets.

[0107] Continued retraction of an outer shaft or sheath (and/or distal movement of working end 1104 relative to an outer sheath or shaft) deploys first expandable member 1108. In this embodiment, first expandable scaffold 1108 has been expanded and positioned (as shown) in a deployed configuration such that proximal end 1121 is in the ascending aorta AA, and proximal to leaflets “VL.” Distal end 1122 has also been positioned proximal to leaflets VL, but in some methods distal end 1122 may extend slightly axially within the leaflets VL. This embodiment is an example of a method in which at least half of 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 the AA. This is also an example of a method in which at least half of first impeller 1116 is positioned within the AA, and also an embodiment in which the entire first impeller 1116 is positioned within the AA.

[0108] At any time during or after deployment of pump portion 1104, the position of the pump portion can be assessed in any way, such as under fluoroscopy. The position of the pump portion can be adjusted at any time during or after deployment. For example, after second expandable scaffold 1110 is released but before first expandable member 1108 is released, pump portion 1104 can be moved axially (distally or proximally) to reposition the pump portion. Additionally, for example, the pump portion can be repositioned after the entire working portion has been released from a sheath to a desired final position.

[0109] It is understood that the positions of the components (relative to the anatomy) shown in Figure 4 are considered exemplary final positions for the different components of working portion 1104, even if there was repositioning that occurred after initial deployment.

[0110] The one or more expandable members herein can be configured to be, and can be expanded in a variety of ways, such as via self-expansion, mechanical actuation (e.g., one or more axially directed forces on the expandable member, expanded with a separate balloon positioned radially within the expandable member and inflated to push radially outward on the expandable member), or a combination thereof.

[0111] Expansion as used herein refers generally to reconfiguration to a larger profile with a larger radially outermost dimension (relative to the longitudinal axis), regardless of the specific manner in which the one or more components are expanded. For example, a stent that self- expands and/or is subject to a radially outward force can “expand” as that term is used herein. A device that unfurls or unrolls can also assume a larger profile, and can be considered to expand as that term is used herein. [0112] The impellers can similarly be adapted and configured to be, and can be expanded in a variety of ways depending on their construction. For examples, one or more impellers can, upon release from a sheath, automatically revert to or towards a different larger profile configuration due to the material(s) and/or construction of the impeller design (see, for example, U.S. Pat. No. 6,533,716, or U.S. Pat. No. 7,393,181, both of which are incorporated by reference herein for all purposes). Retraction of an outer restraint can thus, in some embodiments, allow both the expandable member and the impeller to revert naturally to a larger profile, deployed configuration without any further actuation.

[0113] As shown in the example in Figure 4, the working portion includes first and second impellers that are spaced on either side of an aortic valve, each disposed within a separate expandable member. This is in contrast to some designs in which a working portion includes a single elongate expandable member. Rather than a single generally tubular expandable member extending all the way across the valve, working end 1104 includes a conduit 1112 extending between expandable members 1108 and 1110. The conduit is more flexible and deformable than the expandable baskets, which can allow for more deformation of the working portion at the location of the leaflets than would occur if an expandable member spanned the aortic valve leaflets. This can cause less damage to the leaflets after the working portion has been deployed in the subject.

[0114] Additionally, forces on a central region of a single expandable member from the leaflets might translate axially to other regions of the expandable member, perhaps causing undesired deformation of the expandable member at the locations of the one or more impellers. This may cause the outer expandable member to contact the impeller, undesirably interfering with the rotation of the impeller. Designs that include separate expandable members around each impeller, particularly where each expandable member and each impeller are supported at both ends (i.e., distal and proximal), result in a high level of precision in locating the impeller relative to the expandable member. Two separate expandable members may be able to more reliably retain their deployed configurations compared with a single expandable member.

[0115] As described herein above, it may be desirable to be able to reconfigure the working portion so that it can be delivered within a 9F sheath and still obtain high enough flow rates when in use, which is not possible with some products currently in development and/or testing. For example, some products are too large to be able to be reconfigured to a small enough delivery profile, while some smaller designs may not be able to achieve the desired high flow rates. An exemplary advantage of the examples in Figures 1, 2, 3A-3D and 4 is that, for example, the first and second impellers can work together to achieve the desired flow rates, and by having two axially spaced impellers, the overall working portion can be reconfigured to a smaller delivery profile than designs in which a single impeller is used to achieved the desired flow rates. These embodiments thus use a plurality of smaller, reconfigurable impellers that are axially spaced to achieve both the desired smaller delivery profile as well as to achieve the desired high flow rates.

[0116] The embodiment herein can thus achieve a smaller delivery profile while maintaining sufficiently high flow rates, while creating a more deformable and flexible central region of the working portion, the exemplary benefits of which are described above (e.g., interfacing with delicate valve leaflets).

[0117] Figure 5 illustrates a working portion that is similar to the working portion shown in Figure 1. Working portion 265 includes proximal impeller 266, distal impeller 267, both of which are coupled to drive shaft 278, which extends into distal bearing housing 272. There is a similar proximal bearing housing at the proximal end of the working portion. Working portion also includes expandable scaffold or member, referred to 270 generally, and blood conduit 268 that is secured to the expandable member and extends almost the entire length of expandable member. Expandable member 270 includes distal struts 271 that extend to and are secured to strut support 273, which is secured to distal tip 273. Expandable member 270 also includes proximal struts there are secured to a proximal strut support. All features similar to that shown in Figure 1 are incorporated by reference for all purposes into this embodiment even if not explicitly stated. Expandable member 265 also includes helical tension member 269 that is disposed along the periphery of the expandable member, and has a helical configuration when the expandable member is in the expanded configuration as shown. The helical tension member 269 is disposed and adapted to induce rotation wrap upon collapse. Working portion 265 can be collapsed from the shown expanded configuration while simultaneously rotating one or both impellers at a relatively slow speed to facilitate curled collapse of the impellers due to interaction with the expandable member. Helical tension member 269 (or a helical arrangement of expandable member cells) will act as a collective tension member and is configured so that when the expandable basket is pulled in tension along its length to collapse (such as by stretching to a much greater length, such as approximately doubling in length) tension member 269 is pulled into a straighter alignment, which causes rotation/twisting of the desired segment(s) of the expandable member during collapse, which causes the impeller blades to wrap radially inward as the expandable member and blades collapse. An exemplary configuration of such a tension member would have a curvilinear configuration when in helical form that is approximately equal to the maximum length of the expandable member when collapsed. In alternative embodiments, only the portion(s) of the expandable member that encloses a collapsible impeller is caused to rotate upon collapse. [0118] There are alternative ways to construct the working portion to cause rotation of the expandable member upon collapse by elongation (and thus cause wrapping and collapse of the impeller blades). Any expandable member can be constructed with this feature, even in dual impeller designs. For example, with an expandable member that includes a plurality of “cells,” as that term is commonly known (e.g., a laser cut elongate member), the expandable member may have a plurality of particular cells that together define a particular configuration such as a helical configuration, wherein the cells that define the configuration have different physical characteristics than other cells in the expandable member. In some embodiments the expandable member can have a braided construction, and the twist region may constitute the entire group of wires, or a significant portion (e.g., more than half), of the braided wires. Such a twisted braid construction may be accomplished, for example, during the braiding process, such as by twisting the mandrel that the wires are braided onto as the mandrel is pulled along, especially along the length of the largest-diameter portion of the braided structure. The construction could also be accomplished during a second operation of the construction process, such as mechanically twisting a braided structure prior to heat-setting the wound profile over a shaped mandrel.

[0119] Any of the blood conduits herein act to, are configured to, and are made of material(s) that create a fluid lumen therein between a first end (e.g., distal end) and a second end (e.g., proximal end). Fluid flows into the inflow region, through the fluid lumen, and then out of an outflow region. Flow into the inflow region may be labeled herein as “I,” and flow out at the outflow region may be labeled “O.” Any of the conduits herein can be impermeable. Any of the conduits herein can alternatively be semipermeable. Any of the conduits herein may also be porous, but will still define a fluid lumen therethrough. In some embodiments the conduit is a membrane, or other relatively thin layered member. Any of the conduits herein, unless indicated to the contrary, can be secured to an expandable member such that the conduit, where is it secured, can be radially inside and/or outside of the expandable member. For example, a conduit may extend radially within the expandable member so that inner surface of the conduit is radially within the expandable member where it is secured to the expandable member.

[0120] Any of the expandable scaffolds or member(s) herein may be constructed of a variety of materials and in a variety of ways. For example, the expandable member may have a braided construction, or it can be formed by laser machining. The material can be deformable, such as nitinol. The expandable member can be self-expanding or can be adapted to be at least partially actively expanded.

[0121] In some embodiments, the expandable scaffold or member is adapted to self-expand when released from within a containing tubular member such as a delivery catheter, a guide catheter or an access sheath. In some alternative embodiments, the expandable member is adapted to expand by active expansion, such as action of a pull-rod that moves at least one of the distal end and the proximal end of the expandable member toward each other. In alternative embodiments, the deployed configuration can be influenced by the configuration of one or more expandable structures. In some embodiments, the one or more expandable members can deployed, at least in part, through the influence of blood flowing through the conduit. Any combination of the above mechanisms of expansion may be used.

[0122] The blood pumps and fluid movement devices, system and methods herein can be used and positioned in a variety of locations within a body. While specific examples may be provided herein, it is understood that that the working portions can be positioned in different regions of a body than those specifically described herein.

[0123] In any of the embodiments herein in which the catheter blood pump includes a plurality of impellers, the device can be adapted such that the impellers rotate at different speeds. Figure 6A illustrates a medical device that includes gearset 1340 coupled to both inner drive member 1338 and outer drive member 1336, which are in operable communication with distal impeller 1334 and proximal impeller 1332, respectively. The device also includes motor 1342, which drives the rotation of inner drive member 1338. Inner drive member 1338 extends through outer drive member 1336. Activation of the motor 1332 causes the two impellers to rotate at different speeds due to an underdrive or overdrive ratio. Gearset 1340 can be adapted to drive either the proximal or distal impeller faster than the other. Any of the devices herein can include any of the gearsets herein to drive the impellers at different speeds.

[0124] Figure 6B illustrates a portion of an alternative embodiment of a dual impeller device (1350) that is also adapted such that the different impellers rotate at different speeds. Gearset 1356 is coupled to both inner drive member 1351 and outer drive member 1353, which are coupled to distal impeller 1352 and proximal impeller 1354, respectively. The device also includes a motor like in Figure 6A. Figures 6A and 6B illustrate how a gearset can be adapted to drive the proximal impeller slower or faster than the distal impeller.

[0125] Figure 7 illustrates an exemplary alternative embodiment of fluid pump 1370 that can rotate first and second impellers at different speeds. First motor 1382 drives cable 1376, which is coupled to distal impeller 1372, while second motor 1384 drives outer drive member 1378 (via gearset 1380), which is coupled to proximal impeller 1374. Drive cable 1376 extends through outer drive member 1378. The motors can be individually controlled and operated, and thus the speeds of the two impellers can be controlled separately. This system setup can be used with any system herein that includes a plurality of impellers.

[0126] In some embodiments, a common drive mechanism (e.g., cable and/or shaft) can drive the rotation of two (or more) impellers, but the blade pitch of the two impellers (angle of rotational curvature) can be different, with the distal or proximal impeller having a steeper or more gradual angle than the other impeller. This can produce a similar effect to having a gearset. Figure 6C shows a portion of a medical device (1360) that includes common drive cable 1366 coupled to proximal impeller 1364 and distal impeller 1362, and to a motor not shown. The proximal impellers herein can have a greater or less pitch than the distal impellers herein. Any of the working portions (or distal portions) herein with a plurality of impellers can be modified to include first and second impellers with different pitches.

[0127] In any of the embodiments herein, the pump portion may have a compliant or semi- compliant (referred to generally together as “compliant”) exterior structure. In various embodiments, the compliant portion is pliable. In various embodiments, the compliant portion deforms only partially under pressure. For example, the central portion of the pump may be formed of a compliant exterior structure such that it deforms in response to forces of the valve.

In this manner the exterior forces of the pump on the valve leaflets are reduced. This can help prevent damage to the valve at the location where it spans the valve.

[0128] Figure 8 illustrates an exemplary embodiment of a pump portion that includes first, second and third axially spaced impellers 152, each of which is disposed within an expandable member 154. Conduit 155 can extend along the length of the pump portion, as in described in various embodiments herein, which can help create and define the fluid lumen. In alternative embodiments, however, the first, second, and third impellers may be disposed within a single expandable member, similar to that shown in Figure 1. In Figure 8, a fluid lumen extends from a distal end to a proximal end, features of which are described elsewhere herein. The embodiment in Figure 8 can include any other suitable feature, including methods of use, described herein. [0129] The embodiment in Figure 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 to the bend is not axially aligned with a proximal region of the housing proximal to the bend along an axis. In this embodiment there are two bends 150 and 151 formed in the housing, each one between two adjacent impellers.

[0130] In a method of use, a bend formed in a housing can be positioned to span a valve, such as the aortic valve shown in Figure 8. In this method of placement, a central impeller and distal- most impeller are positioned in the left ventricle, and a proximal-most impeller is positioned in the ascending aorta. Bend 151 is positioned just downstream to the aortic valve.

[0131] A bend such as bend 150 or 151 can be incorporated into any of the embodiments or designs herein. The bend may be a preformed angle or may be adjustable in situ.

[0132] In any of the embodiments herein, unless indicated to the contrary, the outer housing can have a substantially uniform diameter along its length. [0133] In Figure 8, the pump is positioned via the axillary artery, which is an exemplary method of accessing the aortic valve, and which allows the patient to walk and be active with less interruption. Any of the devices herein can be positioned via the axillary artery. It will be appreciated from the description herein, however, that the pump may be introduced and tracked into position in various manners including a femoral approach over the aortic arch.

[0134] One aspect of the disclosure is a catheter blood pump that includes a distal impeller axially spaced from a proximal impeller. Distal and proximal impellers may be axially spaced from each other. For example, the distal and proximal impellers may be connected solely by their individual attachment to a common drive mechanism. This is different from a single impeller having multiple blade rows or sections. A distal impeller as that phrase is used herein does not necessarily mean a distal-most impeller of the pump, but can refer generally to an impeller that is positioned further distally than a proximal impeller, even if there is an additional impeller than is disposed further distally than the distal impeller. Similarly, a proximal impeller as that phrase is used herein does not necessarily mean a proximal-most impeller of the pump, but can refer generally to an impeller that is positioned further proximally than a proximal impeller, even if there is an additional impeller than is disposed further proximally than the proximal impeller. Axial spacing (or some derivative thereof) refers to spacing along the length of a pump portion, such as along a longitudinal axis of the pump portion, even if there is a bend in the pump portion. In various embodiments, each of the proximal and distal impellers are positioned within respective housings and configured to maintain a precise, consistent tip gap, and the span between the impellers has a relatively more flexible (or completely flexible) fluid lumen. For example, each of the impellers may be positioned within a respective housing having relatively rigid outer wall to resist radial collapse. The sections between the impellers may be relatively rigid, in some embodiments the section is held open primarily by the fluid pressure within.

[0135] Although not required for the embodiments therein, there may be advantages to having a minimum axial spacing between a proximal impeller and a distal impeller. For example, a pump portion may be delivered to a target location through parts of the anatomy that have relatively tight bends, such as, for example, an aorta, and down into the aortic valve. For example, a pump portion may be delivered through a femoral artery access and to an aortic valve. 11 can be advantageous to have a system that is easier to bend so that it is easier to deliver the system through the bend(s) in the anatomy. Some designs where multiple impellers are quite close to each other may make the system, along the length that spans the multiple impellers, relatively stiff along that entire length that spans the multiple impellers. Spacing the impellers apart axially, and optionally providing a relatively flexible region in between the impellers, can create a part of the system that is more flexible, is easier to bend, and can be advanced through the bends more easily and more safely. An additional exemplary advantage is that the axial spacing can allow for a relatively more compliant region between the impellers, which can be positioned at, for example, the location of a valve (e.g., an aortic valve). Furthermore, there are other potential advantages and functional differences between the various embodiments herein and typical multistage pumps. A typical multistage pump includes rows of blades (sometimes referred to as impellers) in close functional spacing such that the rows of blades act together as a synchronized stage. One will appreciate that the flow may separate as it passes through the distal impeller. In various embodiments as described herein, distal and proximal impellers can be spaced sufficiently apart such that the flow separation from the distal impeller is substantially reduced (i.e., increased flow reattachment) and the localized turbulent flow is dissipated before the flow enters the proximal impeller.

[0136] In any of the embodiments or in any part of the description herein that include a distal impeller and a proximal impeller, the axial spacing between a distal end of the proximal impeller and a proximal end of the distal impeller can be from 1.5 cm to 25 cm (inclusive) along a longitudinal axis of the pump portion, or along a longitudinal axis of a housing portion that includes a fluid lumen. The distance may be measured when the pump portion, including any impellers, is in an expanded configuration. This exemplary range can provide the exemplary flexibility benefits described herein as the pump portion is delivered through curved portions of the anatomy, such as, for example, an aortic valve via an aorta. Figure 9 (shown outside a patient in an expanded configuration) illustrates length Lc, which illustrates an axial spacing between impellers, and in some embodiments may be from 1.5 cm to 25 cm as set forth herein. In embodiments in which there may be more than two impellers, any two adjacent impellers (i.e., impellers that do not have any other rotating impeller in between them) may be spaced axially by any of the axial spacing distances described herein.

[0137] While some embodiments include a proximal impeller distal end that is axially spaced 1.5 cm to 25 cm from a distal impeller proximal end along an axis, the disclosure herein also includes any axial spacings that are subranges within that general range of 1.5 cm to 25 cm.

That is, the disclosure includes all ranges that have any lower limit from 1.5 and above in that range, and all subranges that have any upper limit from 25 cm and below. The examples below provide exemplary subranges. In some embodiments, a proximal impeller distal end is axially spaced 1.5 cm to 20 cm from a distal impeller proximal end along an axis, 1.5 cm to 15 cm, 1.5 cm to 10 cm, 1.5 cm to 7.5 cm, 1.5 cm to 6 cm, 1.5 cm to 4.5 cm, 1.5 cm to 3 cm. In some embodiments the axial spacing is 2 cm to 20 cm, 2 cm to 15 cm, 2 cm to 12 cm, 2 cm to 10 cm,

2 cm to 7.5 cm, 2 cm to 6 cm, 2 cm to 4.5 cm, 2 cm to 3 cm. In some embodiments the axial spacing is 2.5 cm to 15 cm, 2.5 cm to 12.5 cm, 2.5 cm to 10 cm, 2.5 cm to 7.5 cm, or 2.5 cm to 5 cm (e.g., 3 cm). In some embodiments the axial spacing is 3 cm to 20 cm, 3 cm to 15 cm, 3 cm to 10 cm, 3 cm to 7.5 cm, 3 cm to 6 cm, or 3 cm to 4.5 cm. In some embodiments the axial spacing is 4 cm to 20 cm, 4 cm to 15 cm, 4 cm to 10 cm, 4 cm to 7.5 cm, 4 cm to 6 cm, or 4 cm to 4.5 cm. In some embodiments the axial spacing is 5 cm to 20 cm, 5 cm to 15 cm, 5 cm to 10 cm, 5 cm to 7.5 cm, or 5 cm to 6 cm. In some embodiments the axial spacing is 6 cm to 20 cm, 6 cm to 15 cm, 6 cm to 10 cm, or 6 cm to 7.5 cm. In some embodiments the axial spacing is 7 cm to 20 cm, 7 cm to 15 cm, or 7 cm to 10 cm. In some embodiments the axial spacing is 8 cm to 20 cm, 8 cm to 15 cm, or 8 cm to 10 cm. In some embodiments the axial spacing is 9 cm to 20 cm, 9 cm to 15 cm, or 9 cm to 10 cm. In various embodiments, the fluid lumen between the impellers is relatively unsupported.

[0138] In any of the embodiments herein the one or more impellers may have a length, as measured axially between an impeller distal end and an impeller proximal end (shown as “LSD” and “LSP”, respectively, in Figure 9), from .5 cm to 10 cm, or any subrange thereof. The examples below provide exemplary subranges. In some embodiments the impeller axial length is from .5 cm to 7.5 cm, from .5 cm to 5 cm, from .5 cm to 4 cm, from .5 cm to 3 cm, from .5 cm to 2, or from .5 cm to 1.5 cm. In some embodiments the impeller axial length is from .8 cm to 7.5 cm, from .8 cm to 5 cm, from .8 cm to 4 cm, from .8 cm to 3 cm, from .8 cm to 2 cm, or from .8 cm to 1.5 cm. In some embodiments the impeller axial length is from 1 cm to 7.5 cm, from 1 cm to 5 cm, from 1 cm to 4 cm, from 1 cm to 3 cm, from 1 cm to 2 cm, or from 1 cm to 1.5 cm. In some embodiments the impeller axial length is from 1.2 cm to 7.5 cm, from 1.2 cm to 5 cm, from 1.2 cm to 4 cm, from 1.2 cm to 3 cm, from 1.2 to 2 cm, or from 1.2 cm to 1.5 cm. In some embodiments the impeller axial length is from 1.5 cm to 7.5 cm, from 1.5 cm to 5 cm, from 1.5 cm to 4 cm, from 1.5 cm to 3 cm, or from 1.5 cm to 2 cm. In some embodiments the impeller axial length is from 2 cm to 7.5 cm, from 2 cm to 5 cm, from 2 cm to 4 cm, or from 2 cm to 3cm. In some embodiments the impeller axial length is from 3 cm to 7.5 cm, from 3 cm to 5 cm, or from 3 cm to 4 cm. In some embodiments the impeller axial length is from 4 cm to 7.5 cm, or from 4 cm to 5 cm.

[0139] In any of the embodiments herein the fluid lumen can have a length from a distal end to a proximal end, shown as length Lp in Figure 9. In some embodiments the fluid lumen length Lp is from 4 cm to 40 cm, or any subrange therein. For example, in some embodiments the length Lp can be from 4 cm to 30 cm, from 4 cm to 20 cm, from 4 cm to 18 cm, from 4 cm to 16 cm, from 4 cm to 14 cm, from 4 cm to 12 cm, from 4 cm to 10 cm, from 4 cm to 8 cm, from 4 cm to 6 cm. [0140] In any of the embodiments herein the housing can have a deployed diameter, at least the location of an impeller (and optionally at a location between impellers), shown as dimension Dp in Figure 9. In some embodiments Dp can be from .3 cm to 1.5 cm, or any subrange therein.

For example, Dp may be from .4 cm to 1.4 cm, from .4 cm to 1.2 cm, from .4 cm to 1.0 cm, from .4 cm to .8 cm, or from .4 cm to .6 cm. In some embodiments, Dp may be from .5 cm to 1.4 cm, from .5 cm to 1.2 cm, from .5 cm to 1.0 cm, from .5 cm to .8 cm, or from .5 cm to .6 cm. In some embodiments Dp may be from .6 cm to 1.4 cm, from .6 cm to 1.2 cm, from .6 cm to 1.0 cm, or from .6 cm to .8 cm. In some embodiments Dp may be from .7 cm to 1.4 cm, from .7 cm to 1.2 cm, from .7 cm to 1.0 cm, or from .7 cm to .8 cm.

[0141] In any of the embodiments herein an impeller can have a deployed diameter, shown as dimension Di in Figure 9. In some embodiments Di can be from 1 mm - 30 mm, or any subrange therein. For example, in some embodiments Di may be from 1 mm - 15 mm, from 2 mm - 12 mm, from 2.5 mm - 10 mm, or 3 mm - 8mm.

[0142] In any of the embodiments herein, a tip gap exists between an impeller outer diameter and a fluid lumen inner diameter. In some embodiments the tip gap can be from 0.01 mm - lmm, such as .05 mm to .8 mm, or such as 0.1 mm - 0.5 mm.

[0143] In any of the embodiments herein that includes multiple impellers, the axial spacing between impellers (along the length of the pump portion, even if there is a bend in the pump portion) can be from 2 mm to 100 mm, or any combination of upper and lower limits inclusive of 5 and 100 mm (e.g., from 10 mm - 80mm, from 15 mm - 70 mm, from 20 mm-50mm, 2 mm -45 mm, etc.).

[0144] Any of the pump portions herein that include a plurality of impellers may also include more than two impellers, such as three, four, or five impellers (for example).

[0145] Figure 10 illustrates an expandable scaffold 250 that may be one of at least two expandable scaffolds of a pump portion, such as the expandable scaffolds in Figures 3A-3D, wherein each expandable scaffold at least partially surrounds an impeller. The scaffold design in Figure 10 has proximal struts 251 (only one labeled) extending axially therefrom. Having a separate expandable scaffold 250 for each impeller provides for the ability to have different geometries for any of the individual impellers. Additionally, this design reduces the amount of scaffold material (e.g., Nitinol) over the length of the expandable blood conduit, which may offer increased tracking when sheathed. A potential challenge with these designs may include creating a continuous membrane between the expandable scaffolds in the absence of an axially extending scaffolding material (see Figure 3 A). Any other aspect of the expandable scaffolds or members herein, such as those described in Figures 3A-3D, may be incorporated by reference into this exemplary design. Struts 251 may be disposed at a pump inflow or outflow. Struts 251 may be proximal struts or they may be distal struts.

[0146] Figure 11 show an exemplary scaffold along an length of the blood conduit. Central region “CR” may be axially between proximal and distal impellers. Central region “CR” flexibility is increased relative to scaffold impeller regions “IR” due to breaks or discontinuities in the scaffold pattern in the central region. The scaffold has relatively more rigid impeller sections “IR” adjacent the central region where impellers may be disposed (not shown). The relatively increased rigidity in the impeller regions IR may help maintain tip gap and impeller concentricity. This pump scaffold pattern provides for a flexibility distribution, along its length, of a proximal section of relatively less flexibility (“IR”), a central region “CR” of relatively higher flexibility, and a distal section “IR” of relatively less flexibility than the central region. The relatively less flexible sections (i.e., the two IR regions) are where proximal and distal impellers may be disposed (not shown but other embodiments are fully incorporated herein in this regard), with a relatively more flexible region in between. Exemplary benefits of the relative flexibility in these respective sections are described elsewhere herein. Figure 11 is an example of a scaffold that is continuous from a first end region to a second end region, even though there are breaks or discontinuities in some locations of the scaffold. There is at least one line that can be traced along a continuous structural path from a first end region to a second end region.

[0147] The following disclosure provides exemplary method steps that may be performed when using any of the blood pumps, or portions thereof, described herein. It is understood that not all of the steps need to be performed, but rather the steps are intended to be an illustrative procedure. It is also intended that, if suitable, in some instances the order of one or more steps may be different. Before use, the blood pump can be prepared for use by priming the lumens (including any annular spaces) and pump assembly with sterile solution (e.g., heparinized saline) to remove any air bubbles from any fluid lines. The catheter, including any number of purge lines, may then be connected to a console. Alternatively, the catheter may be connected to a console and/or a separate pump that are used to prime the catheter to remove air bubbles.

[0148] After priming the catheter, access to the patient’s vasculature can be obtained (e.g., without limitation, via femoral access) using an appropriately sized introducer sheath. Using standard valve crossing techniques, a diagnostic pigtail catheter may then be advanced over a, for example, 0.035” guide wire until the pigtail catheter is positioned securely in the target location (e.g., left ventricle). The guidewire can then be removed and a second wire 320 (e.g., a 0.018" wire) can be inserted through the pigtail catheter. The pigtail catheter can then be removed (see Figure 12A), and the blood pump 321 (including a catheter, catheter sheath, and pump portion within the sheath; see Figure 12B) can be advanced over the second wire towards a target location, such as spanning an aortic valve “AV,” and into a target location (e.g., left ventricle “LV”), using, for example, one or more radiopaque markers to position the blood pump.

[0149] Once proper placement is confirmed, the catheter sheath 322 (see Figure 12C) can be retracted, exposing first a distal region of the pump portion. In Figure 12C a distal region of an expandable housing has been released from sheath 322 and is expanded, as is distal impeller 324. A proximal end of housing 323 and a proximal impeller are not yet released from sheath 322. Continued retraction of sheath 322 beyond the proximal end of housing 323 allows the housing 323 and proximal impeller 325 to expand (see Figure 12D). The inflow region (shown with arrows even though the impellers are not yet rotating) and the distal impeller are in the left ventricle. The outflow (shown with arrows even though the impellers are not rotating yet) and proximal impeller are in the ascending aorta AA. The region of the outer housing in between the two impellers, which may be more flexible than the housing regions surrounding the impellers, as described in more detail herein, spans the aortic valve AV. In an exemplary operating position as shown, an inlet portion of the pump portion will be distal to the aortic valve, in the left ventricle, and an outlet of the pump portion will be proximal to the aortic valve, in the ascending aorta (“AA”).

[0150] The second wire (e.g., an 0.018” guidewire) may then be moved prior to operation of the pump assembly (see Figure 12E). If desired or needed, the pump portion can be deflected (active or passively) at one or more locations as described herein, as illustrated in Figure 12F. For example, a region between two impellers can be deflected by tensioning a tensioning member that extends to a location between two impellers. The deflection may be desired or needed to accommodate the specific anatomy. As needed, the pump portion can be repositioned to achieve the intended placement, such as, for example, having a first impeller on one side of a heart valve and a second impeller on a second side of the heart valve. It is understood that in Figure 12F, the pump portion is not in any way interfering or interacting with the mitral valve, even if it may appear that way from the figure.

[0151] As set forth above, this disclosure includes catheter blood pumps that include an expandable pump portion extending distally relative to a catheter. The pump portions include an impeller housing that includes an expandable blood conduit that defines a blood lumen. The blood conduit may include one or more scaffold sections that together may also be referred to herein as a single scaffold. In some exemplary embodiments the expandable blood conduit may include one or more of a proximal impeller scaffold, a distal impeller scaffold, and a central scaffold disposed between the proximal impeller scaffold and the distal impeller scaffold, where any combination thereof may also be referred to herein as a scaffold. Any individual proximal impeller scaffold or distal impeller scaffold may also be referred to herein as an expandable member, such as is shown in figures 3A-3D. In some embodiments the expandable blood conduit may include a proximal impeller scaffold and additional scaffold extending distally therefrom, such as if the pump portion includes a proximal impeller but does not include a distal impeller.

In any of the embodiments herein, a reference to a distal impeller is only by way of example, and pump portions herein need not include a distal impeller. Central scaffolds herein are generally less stiff in response to a radially inward force than a proximal scaffold, and optionally also less stiff than a distal scaffold, such as a distal impeller scaffold. Exemplary advantages of central scaffold sections that are less stiffness are set forth elsewhere herein. The blood conduit may also include a membrane coupled to the one or more scaffolds, the membrane at least partially defining the blood lumen. Membranes in this context may incorporate by reference herein the disclosure of conduits, including any feature or method of manufacturing described above. The catheter blood pumps may include an impeller disposed in a proximal region of the impeller housing, which may be a proximal impeller. The catheter blood pumps may also include a distal impeller in a distal region of the impeller housing. Exemplary impellers, including exemplary proximal and distal impellers, are set forth herein by way of example. An impeller that is at least partially within a portion of a scaffold may be described with respect to the relative position of the scaffold, such the a proximal impeller within at least a portion of a proximal scaffold, or a distal impeller within at least a portion of a distal scaffold.

[0152] When a proximal impeller is described as being within a proximal scaffold, it is understood that the proximal scaffold need not axially extend over an entire length of the impeller, as long as there is some amount of axial overlap. For example, some proximal impellers herein extend proximally from a blood conduit, and a proximal region of the proximal impeller is not surrounded by a blood conduit scaffold, while a distal region of the impeller is surrounded by scaffold. Similarly, when a distal impeller herein (if the pump includes a distal impeller) is described as being within a distal scaffold, it is understood that the distal scaffold need not axially extend over an entire length of the impeller, as long as there is some degree of axial overlap therebetween.

[0153] Figures 13A-17 illustrate exemplary designs for expandable scaffolds herein, which may at least partially surround an impeller that is at least partially disposed within a conduit that creates a fluid lumen. The scaffold patterns in Figures 13A-17 may be scaffold patterns that only extend over a particular impeller (e.g., a proximal basket or distal basket), or they may be scaffold patterns that extend over an entire blood conduit scaffold.

[0154] Figures 13A-17 illustrate expandable support members or scaffolds that each have an expanded configuration, wherein in the expanded configuration the support member has a plurality of continuous axially extending elements (e.g., 408, 410, 420, 430, 440) that are continuous and axially extending over at least 50% of a length of the expandable support member (e.g., L_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 continuous axially extending elements. In some embodiment the axially extending elements are linear or substantially linear.

[0155] Figures 13A-13C illustrate an exemplary pump portion 400 or a portion thereof that comprises an expandable impeller housing 402, wherein the expandable impeller housing having a blood conduit 404, the conduit defining a blood lumen between an housing inflow “I” and a housing outflow “O”. The expandable impeller housing also includes an expandable scaffold or support member 406 at least partially surrounding an impeller (not shown in figures 13A-13C) that is at least partially disposed within the conduit. Figures 14A-17 illustrate an expandable scaffold of the pump portion. It is understood that any expandable scaffold in any of figures 13A-17 may be used in place of any expandable scaffold herein. Impeller housing 402 may illustrate the entire impeller housing, or it may only represent only a portion thereof, including only a single scaffold section, such as with any of the multi-impeller designs herein. It is thus understood that the structure shown in figures 13A-C may only be a portion of the expandable housing of a pump portion. For example, a pump portion may include two of the expandable scaffold sections shown in figures 13A-C, axially spaced apart, and coupled by a flexible membrane, for example.

[0156] Figures 13A-C illustrate an expandable impeller housing that includes a plurality of axially extending elements 408 circumferentially spaced apart around the housing 402 from adjacent axially extending elements, as shown. Figures 13A and 13B show an expanded configuration of the housing, while figure 13C illustrates a model of a flat, unexpanded configuration with unitary struts 401 extending axially therefrom, as shown. The plurality of axially extending elements may be referred to as “elements” in the context of scaffolds for simplicity, but it is understood that they are not to be considered any other type of “element” herein unless specifically indicated as such. The elements in this embodiment may be axial and linear in the housing expanded configuration. Expandable scaffold 406 also includes circumferential connectors 409 that circumferentially connect adjacent axial elements and extend from one axial element to an adjacent axial element. In this exemplary embodiment all of the connectors have the same general configuration, which includes first and second segments meeting at a rounded peak that is oriented axially (proximally or distally depending on the reference frame), otherwise stated as pointing axially. Length Ls of the scaffold and length Le of the elements is illustrated in figure 13C. Optional struts 401 are shown (which may be unitary with the scaffold). The axial elements 408 in this embodiment extend from a first axial element end 405 to second axial element end 405’, which extend almost the entire length of the scaffold Ls. As shown, ends 405’ of the elements (only one labeled) extend to a distal end region 407’ of the scaffold 406. End 405 extends to proximal end region 407. The pump portion also includes a transition region 411, which includes circumferential extensions of adjacent axial elements, after which they meet to form a strut 401, as shown.

[0157] Figures 14A (expanded) and 14B (unexpanded) illustrate an exemplary expandable scaffold 406’, which includes a plurality of axially extending elements 410. A first set of connectors 412 have “S” configurations, and a second circumferentially adjacent set of connectors 414 have inverse (reverse) “S” shapes. In the expanded configuration in figure 14A the axial elements 410 may be linear, or they may have a slight curvilinear configuration as shown. Scaffold 406’ includes transition region 411’, which may have similar features to the transition region 411 herein. The relevant description from any other embodiment may be incorporated with the scaffold in figures 14A-B (e.g., lengths of scaffold or support member and axial elements, transition region, etc.). Some of the optional struts 413 are shown, as are ends 405/405’ of the axial elements. Scaffold 406’ may be proximal or distal scaffold, or it may extend along the length of the impeller housing.

[0158] Figures 15A and 15B illustrate an exemplary expandable scaffold 406” that is similar to those in figure 13, 14, 16, and 17. Axially extending elements 420 are shown, adjacent ones of which are connected by circumferential connectors 422 and 424, ends of which are axially offset. A first set of connectors 422 has a general S configuration, while a second set of connectors 424 are reverse S-shaped. In this embodiments the axially extending elements 420 are curvilinear, as shown. The pattern of S and inverse-S alternates around the expandable member, as it does in the scaffolds in figures 14A and 14B. Scaffold 406” also includes a transition region 421, examples of which are described elsewhere herein. Scaffold 406” may be proximal or distal scaffold, or it may extend along the length of the impeller housing.

[0159] Figure 16 illustrates a collapsed (unexpanded) configuration of an exemplary scaffold 406”’, which may have any other suitable features of any other support member or scaffold herein. Axially extending elements 430 are shown, connected by first set of S-shaped connectors 434 and a second set of inverse-S shaped connectors 432. The pattern of S and inverse-S shapes alternates circumferentially around the scaffold 406”’ as shown. Scaffold 406”’ may be proximal or distal scaffold, or it may extend along the length of the impeller housing.

[0160] Figure 17 illustrates a collapsed (unexpanded) configuration of an exemplary scaffold 406””, which may have any other suitable features of any other support member or scaffold herein. Axially extending elements 440 are shown, connected by inverse-S shaped connectors. All sets of the connectors in this embodiment (e.g., set 442 and set 444) have the same configuration, and in this embodiment are all inverse-S shaped. Exemplary struts are shown axially disposed relative to the scaffold 406””, and the scaffold 406”” may include transition sections which are described elsewhere herein. Scaffold 406”” may be a proximal scaffold or a distal scaffold, or it may extend along the length of the impeller housing.

[0161] The scaffolds and blood conduit embodiments in figures 13A-17 are illustrative, and may be modified to include aspects of other embodiments herien. The following decrip tion may provide modifications to the scaffolds in figures 13 A- 17, any of which may be incorporated into any of the scaffolds in figures 13A-17.

[0162] In any of the scaffolds shown in figures 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 scaffold.

[0163] In any of the scaffolds shown in figures 13A-17, at least one of, and optionally all of, the plurality of axially extending elements may be linear. In any of the scaffolds shown in figures 13 A- 17, at least one of, and optionally all of, the plurality of axially extending elements may be curvilinear.

[0164] In any of the scaffolds shown in figures 13A-17, each one of the the plurality of axially extending elements may have proximal and distal ends, wherein the proximal and distal ends are substantially circumferentially aligned.

[0165] In any of the scaffolds shown in figures 13A-17, each of the the plurality of axially extending elements may have a circumferential span (illustrated as “CS” in figure 15 A) that is not larger than 10 degrees circumferetnailly around the expandable scaffold, optionally not larger than 5 degrees of the expandable scaffold.

[0166] In any of the scaffolds shown in figures 13A-17, each of the the plurality of axially extending elements may follow a path that is subtantially parallel with a longitudinal axis of the expandable scaffold.

[0167] In any of the embodiments in figures 13A-17, each of the the plurality of axially extending elements may be continuous and axially extending over at least 55% of a length of the expandable scaffold, optionally over at least 60%, optionally over at least 65%, optionally over at least 70%, optionally over at least 75%, optionally over at least 80%, optionally over at least 85%, optionally over at least 90, optionally over at least 95.

[0168] In any of the scaffolds shown in figures 13A-17, all of the connectors in all of the sets of the plurality of sets of connectors may have the same configuration. In any of the scaffolds shown in figures 13A-17, all of the connectors in all of the sets of the plurality of sets of connectors may not have the same configuration. In any of the scaffolds shown in figures 13A- 17, each individual set of connectors may have a plurality of connectors that have the same configuration. In any of the embodiments in figures 13 A- 17, all of the connectors in all of the sets of the plurality of sets of connectors may have an S- shape. In any of the embodiments in figures 13A-17, all of the connectors in all of the sets of the plurality of sets of connectors may have a reverse (or inverted) S-shape. In any of the scaffolds shown in figures 13A-17, all of the connectors in a first set of connectors may have a S shape. In any of the scaffolds shown in figures 13A-17, a second set of connectors that is circumferentially adjacent to the first set of connnectors may all have an inverted S shape. In any of the scaffolds shown in figures 13A-17, S shape / inverted S shape connectors may alternate around the circumference of the expandable scaffold.

[0169] In any of the embodiments in figures 13A-17, a first set of connectors that extend in a first circumferential direction from a first axially extending element may extend from the first axially extending element at axial locations that are different from the axial locations at which a second set of connectors extend from the first axially extending element in a second circumferential direction (i.e., the connectors have ends that are axially offset).

[0170] In any of the embodiments in figures 13A-17, the expandable scaffold may include a transition region conncting a first axially extending element with a strut, optionally wherein the transition region is considered part of the expandable scaffold. A transition region may also connect the strut with a second axially extending element, the second axially being circumferentially adjacent to the first axially extending around the blood conduit. In any of the scaffolds shown in figures 13A-17, the expandable scaffold may extend along substantially the entire length of the conduit. In any of the scaffolds shown in figures 13A-17, the expandable scaffold may extend along less than 50% of the length of the expandable impeller housing. In any of the embodiments in figures 13A-17, the expandable scaffold may extend only in a region of the expandable housing in which an impeller is disposed.

[0171] In any of the embodiments in figures 13A-17, the expandable impeller housing may include a second expandable scaffold axially spaced from the first expandable scaffold. A second expandable scaffold may have an expanded configuration with a second plurality of axially extending elements that are axially extending over at least 50% of a length of the second expandable scaffold and wherein the second expandable scaffold may also include a plurality of sets of connectors, each set of connectors extending circumferentially between first and second circumferentially adjacent axially extending elements. A second expandable scaffold may include any features set forth in any of the claims or decribed elsewhere herein. In any of the scaffolds shown in figures 13A-17, the expandable scaffold may be unitary, that is, made from a single piece of starting material. [0172] Figures 18A and 18B illustrate an exemplary scaffold 450 comprising a plurality of axially extending elements 452 (eight in this example). Scaffold 450 includes a proximal scaffold 460, a central scaffold 462, and distal scaffold 464. In this example axially extending elements 452 are linear. Central scaffold 462 is connected to proximal scaffold 460 and to distal scaffold 464 in this example, and in particular, is unitary with them in this example. Figure 18B illstrates an expanded configuration, and figure 18A illustrates an as-cut flat illustration of the scaffold. The axially extending elements 452 that are labeled in figure 18B are circumferentially adjacent axial elements. Adjacent axially extending elements are connected by a plurality of circumferential connectors 451, which in this example have general S or inverse-S configurations, which include at least one bend formed therein. As shown, each circumferential connector is circumferentially adjacent to another circumferential connectors, and together they extend around the blood conduit. In this example, as shown, circumferentially adjacent circumferential connectors are displaced axially relative to one another. For example, circumferential connectors 451’ are axially displaced (or axially offset) relative to circumferential connectors 451” . Axially displaced or axially offset in this context refers to proximal ends of the connectors being axially offset, distal ends of the connectors being axially offset, or both. In this example, a section of each one of the axially extending elements connects adjacent circumferential connectors that are axially displaced. For example, section 453 of one of the axially extending elements 452 connects circumferential connector 451’ and 451”, which creates the axially displaced nature of the circumferentially adjacent circumferential connectors. In this example, distal ends of connectors 451” are further distally than the distal ends of the circumferentially adjacent connectors 451’, as shown. Figures 18A and 18B also illustrate a first group of a plurality of circumferential connectors having a first axial position, and a second group of the plurality of circumferential connectors having a second axial position, wherein the first and second axial positions alternate circumferentially around the blood conduit, as shown. [0173] Figures 19A and 19B illustrate an exemplary scaffold 470. Scaffold 470 includes a plurality of axially extending elements 472, which are linear is sections but are not linear along the entire scaffold 470 length. Scaffold 470 also includes connectors 471 that circumferentially connect circumferentially adjacent axial elements 472. Connectors 471 includes peaks that are oriented, or point, axially, and in this example may be oriented distally or proximally. Scaffold 470 includes a proximal scaffold, a central scaffold, and a distal scaffold that are connected, and in this example are unitary, just as with the scaffold in figures 18A and 18B. Both the proximal scaffold, central scaffold, and distal scaffold comprise a plurality of linear axially extending elements spaced apart around the blood conduit, wherein first and second adjacent linear axially extending elements are each connected by a circumferential connector having at least one bend formed therein. The circumferential connectors defining a plurality of circumferential connectors around the blood conduit, and wherein circumferentially adjacent circumferential connectors of the plurality of circumferential connectors are displaced axially relative to one another. Like in figures 18A and 19B, a section 473 of each one of the axially extending elements (in this example linear) connects circumferentially adjacent circumferential connectors that are axially displaced, as shown. Figures 19A and 19B illustrate a first group of a plurality of circumferential connectors having a first axial position, and wherein a second group of the plurality of circumferential connectors have a second axial position, wherein the first and second axial positions alternate circumferentially around the blood conduit. In this embodiment, the proximal, central, and distal scaffolds are generally have the same configuration (except the ends of the distal and proximal scaffolds).

[0174] Scaffold 470 also includes second region 477 that is axially adjacent first region 476, wherein second region 477 comprises a plurality of peaks 478 that are shown oriented orthogonally relative to a long axis of the blood conduit (membrane not shown for clarity). In this example, each of the plurality of peaks 478 is an extension of one of the axially extending elements 472 in the first region 476, as shown. Scaffold 470 also includes third region 479 that is axially adjacent second region 477, the third region 470 comprising a second plurality of linear axially extending elements as shown that are spaced apart around the blood conduit, and a second plurality of circumferential connectors 471, where the second region 477 joins the first region 476 and third region 479. In this example this pattern continues along the length of the scaffold.

[0175] Figure 20A and 20B illustrate exemplary scaffold 500, with figure 20B showing the expanded configuration and figure 20A illustrating a flattened non-expanded configuration. Features that are shown in figures 20A and 20B that are the same as features shown in other scaffolds herein may be expressly included in this embodiment even if not described herewith. Scaffold 500 includes proximal scaffold 510, central scaffold 520 and distal scaffold 530, which are unitary in this embodiment. In this embodiment the central scaffold 520 has a pattern and configuration such that it is less stiff in response to a radially inward force than proximal scaffold 510 and distal scaffold 530. Proximal scaffold 510 may be a proximal impeller scaffold, and distal scaffold 530 may be a distal impeller scaffold, within at least a portion of which a proximal impeller and a distal impeller may be disposed, respectively. Scaffold 500 central scaffold 520 has a pattern that is different than the pattern in scaffold sections 510 and 530. In this example, scaffold sections 510 and 530 have patterns that are substantially the same. Scaffold 500 includes circumferential connectors in proximal scaffold 510, central scaffold 520, and distal scaffold 530, as shown. For example, proximal scaffold 510 includes circumferential connectors 512, and distal scaffold 530 includes circumferential connectors 532. The circumferential connectors in scaffold 500 have the same configurations as circumferential connectors 451 in the scaffold 450 in figures 18A and 18B, and all descriptions thereof are incorporated by reference with the circumferential connectors into all scaffold sections in scaffold 500. For example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which is described in more detail elsewhere herein. The circumferential connectors also have the S and inverse-S configurations, which is described with respect to other scaffolds herein. The central scaffold 520 in scaffold 500 also includes peaks 521 and 521’, similar to peaks 478 in the scaffold in figures 19A and 19B. A first plurality of peaks 521 have a first axial position, and a second plurality of peaks 521’ have a second axial position, which can be seen clearly in figure 20A. The axial position alternates circumferentially around the scaffold, as shown. Peaks 521 and 521’ extend from axially extending elements 522 like the scaffold in figures 19A and 19B. The proximal scaffold and the distal scaffold do not include peaks in this embodiment. Axially extending elements 522 in the central scaffold section have a width that is greater than the width of the scaffold in peak 521 regions, as shown. This difference in width can provide the peak regions with greater flexibility, while the wider axially extending element provide sufficient radial support in the central scaffold. Any of the scaffold sections with the peaks may be considered a first region, and the axially adjacent sections with circumferential connectors and axially extending elements may be considered second regions, examples of which are described elsewhere herein. In this embodiment the axially extending elements are linear as shown, but may be curvilinear in other embodiments.

[0176] Figure 21A and 21B illustrate exemplary scaffold 550, with figure 21B showing the expanded configuration and figure 21A illustrating a flattened non-expanded configuration. Features that are shown in figures 21 A and 2 IB that are the same as features shown in other scaffolds herein may be expressly included in this embodiment even if not described herewith. Scaffold 550 includes proximal scaffold 560, central scaffold 570 and distal scaffold 580, which are unitary in this embodiment. Proximal scaffold 560 may be a proximal impeller scaffold, and distal scaffold 580 may be a distal impeller scaffold, within at least a portion of which a proximal impeller and a distal impeller may be disposed, respectively. Scaffold 550 central scaffold 570 has a pattern that is different than the pattern in scaffold sections 560 and 580. In this example, scaffold sections 560 and 580 have patterns that are substantially the same. Scaffold 550 includes circumferential connectors in proximal scaffold 560, central scaffold 570, and distal scaffold 580, as shown. For example, proximal scaffold 560 includes circumferential connectors 562, and distal scaffold 580 includes circumferential connectors 582. The circumferential connectors in scaffold 550 have the same configurations as circumferential connectors 451 in the scaffold 450 in figures 18A and 18B, and all descriptions thereof are incorporated by reference with the circumferential connectors into all scaffold sections in scaffold 550. For example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which is described in more detail elsewhere herein. The circumferential connectors also have the S and inverse-S configurations, which is described with respect to other scaffolds herein. Elements 571 in the central scaffold extend into the proximal and distal scaffold sections as shown, forming linear axially extending elements in the proximal and distal scaffolds. Axially extending elements 561 in proximal scaffold 560 do not extend into the central scaffold, as shown. Similarly, axially extending elements 581 in distal scaffold 580 do not extend into the central scaffold, as shown. Elements 571 in the central scaffold 570 have helical configurations as shown. Adjacent elements 571 are connected with connectors 572 as shown. Connectors 572 may have any characteristics of any circumferential connectors herein, such as the alternating S and inverse-S configurations. Figure 21A illustrates a flattened non-expanded configuration, and the scaffold 550 may be formed into the configuration shown in figure 2 IB, such as by twisting the ends relative to one another and setting the scaffold in the configuration shown in figure 2 IB.

[0177] Figure 22A and 22B illustrate exemplary scaffold 600, with figure 22B showing the expanded configuration and figure 22A illustrating a flattened non-expanded configuration. Features that are shown in figures 22A and 22B that are the same as features shown in other scaffolds herein may be expressly included in this embodiment even if not described herewith. Scaffold 600 includes proximal scaffold 610, central scaffold 620 and distal scaffold 630, which are unitary in this embodiment. Proximal scaffold 610 may be a proximal impeller scaffold, and distal scaffold 630 may be a distal impeller scaffold, within at least a portion of which a proximal impeller and a distal impeller may be disposed, respectively. Scaffold 600 central scaffold 620 has a pattern that is different than the pattern in scaffold sections 610 and 630. In this example, scaffold sections 610 and 630 have patterns that are substantially the same. Scaffold 600 includes circumferential connectors in proximal scaffold 610, central scaffold 620, and distal scaffold 630, as shown. For example, proximal scaffold 610 includes circumferential connectors 612, and distal scaffold 630 includes circumferential connectors 632. The circumferential connectors in the proximal and distal sections of scaffold 600 have the same configurations as circumferential connectors 451 in the scaffold 450 in figures 18A and 18B, and all descriptions thereof are incorporated by reference with the circumferential connectors into all scaffold sections in scaffold 600. For example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which is described in more detail elsewhere herein, and connect axially extending elements 611 and 631, respectively. The circumferential connectors also have S and inverse-S configurations, which is described with respect to other scaffolds herein. Axially extending elements 621 in the central scaffold extend into the proximal and distal scaffold sections as shown, wherein the elements 621 are linear axially extending elements in the proximal and distal scaffolds as well as the central scaffold. Axially extending elements 611 in proximal scaffold 610 do not extend into the central scaffold, as shown. Similarly, axially extending elements 631 in distal scaffold 630 do not extend into the central scaffold, as shown. Elements 621 in the central scaffold 620 have axially extending linear configurations as shown. Central scaffold 620 includes axially extending elements 621 that are connected by circumferential connectors. The circumferential connectors include a plurality of axially extending elements 624, each of which connect circumferentially adjacent circumferential connectors 622, as shown. When scaffold 600 is expanded to the configuration shown in figure 22B, the circumferential connectors assume the configuration shown, wherein elements 624 are no longer purely axially extending, such that they form an angle with a long axis of the scaffold, as shown.

[0178] Figure 23A and 23B illustrate exemplary scaffold 650, with figure 23B showing the expanded configuration and figure 23A illustrating a flattened non-expanded configuration. Features that are shown in figures 23A and 23B that are the same as features shown in other scaffolds herein may be expressly included in this embodiment even if not described herewith. Scaffold 650 includes proximal scaffold 660, central scaffold 670 and distal scaffold 650, which are unitary in this embodiment. Proximal scaffold 660 may be a proximal impeller scaffold, and distal scaffold 650 may be a distal impeller scaffold, within at least a portion of which a proximal impeller and a distal impeller may be disposed, respectively. Scaffold 650 central scaffold 670 has a pattern that is different than the pattern in scaffold sections 660 and 680. In this example, scaffold sections 660 and 680 have patterns that are substantially the same.

Scaffold 650 includes circumferential connectors in proximal scaffold 660, central scaffold 670, and distal scaffold 680, as shown. For example, proximal scaffold 660 includes circumferential connectors 662, and distal scaffold 650 includes circumferential connectors 682. The circumferential connectors in the proximal and distal sections of scaffold 650 have the same configurations as circumferential connectors 451 in the scaffold 450 in figures 18A and 18B, and all descriptions thereof are incorporated by reference with the circumferential connectors into all scaffold sections in scaffold 650. For example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which is described in more detail elsewhere herein, and connect axially extending elements 661 and 681, respectively. The circumferential connectors also have S and inverse-S configurations, which is described with respect to other scaffolds herein. Axially extending elements 671 in the central scaffold extend into the proximal and distal scaffold sections as shown, wherein the elements 671 are linear axially extending elements in the proximal and distal scaffolds as well as the central scaffold. Axially extending elements 661 in proximal scaffold 660 do not extend into the central scaffold, as shown. Similarly, axially extending elements 681 in distal scaffold 650 do not extend into the central scaffold, as shown. Elements 671 in the central scaffold 670 have axially extending linear configurations as shown. Central scaffold 670 includes axially extending elements 671 that are connected by circumferential connectors. The circumferential connectors include a plurality of axially extending elements 674, each of which connect circumferentially adjacent circumferential connectors 672, as shown. When scaffold 650 is expanded to the configuration shown in figure 23 B, the circumferential connectors 672 assume the configuration shown, wherein elements 674 are no longer purely axially extending, such that they form an angle with a long axis of the scaffold, as shown. Elements 674 in figure 23A are formed by removing material axially disposed between axially adjacent elements 674.

[0179] Figure 24A and 24B illustrate exemplary scaffold 700, with figure 24B showing the expanded configuration and figure 24A illustrating a flattened non-expanded configuration. Features that are shown in figures 24A and 24B that are the same as features shown in other scaffolds herein may be expressly included in this embodiment even if not described herewith. For example, scaffold 700 is the same in some ways to the scaffolds shown in figures 19A, 19B, 20A and 20B. Scaffold 700 includes proximal scaffold 710, central scaffold 720 and distal scaffold 730, which are unitary in this embodiment. Proximal scaffold 710 may be a proximal impeller scaffold, and distal scaffold 730 may be a distal impeller scaffold, within at least a portion of which a proximal impeller and a distal impeller may be disposed, respectively. Scaffold 700 central scaffold 720 has a pattern that is different than the pattern in scaffold sections 710 and 730. In this example, scaffold sections 710 and 730 have patterns that are substantially the same. Scaffold 700 includes circumferential connectors in proximal scaffold 710, in central scaffold 720, and in distal scaffold 730, as shown. For example, proximal scaffold 710 includes circumferential connectors 712, and distal scaffold 730 includes circumferential connectors 732. The circumferential connectors in the proximal and distal sections of scaffold 700 have the same configurations as circumferential connectors 451 in the scaffold 450 in figures 18A and 18B, and all descriptions thereof are incorporated by reference with the circumferential connectors into all scaffold sections in scaffold 700. For example only, circumferentially adjacent circumferential connectors are axially displaced (i.e., axially offset) relative to one another, which is described in more detail elsewhere herein, and connect axially extending elements 711 and 731, respectively. The circumferential connectors also have S and inverse-S configurations alternating circumferentially around the scaffold, which is described with respect to other scaffolds herein. Scaffold 700 includes a plurality of axially extending elements 711, which are linear in sections but do not extend along the entire length of scaffold 700. Scaffold 700 also includes circumferential connectors 712 that circumferentially connect circumferentially adjacent axial elements 711. The proximal scaffold, central scaffold, and distal scaffold comprise a plurality of linear axially extending elements 711, 721, and 731, respectively, that are circumferentially spaced apart around the respective scaffold section, wherein first and second adjacent linear axially extending elements are each connected by a circumferential connector 712, 722, and 732, respectively, having at least one bend formed therein. The circumferential connectors define a plurality of circumferential connectors around the scaffold, and wherein circumferentially adjacent circumferential connectors of the plurality of circumferential connectors are displaced axially relative to one another, as shown and described elsewhere herein. As is the case in figures 18A and 19B, a section of each one of the axially extending elements (in this example linear elements) connects circumferentially adjacent circumferential connectors that are axially displaced, as shown. Figures 24A and 24B illustrate a first group of a plurality of circumferential connectors having a first axial position, and wherein a second group of the plurality of circumferential connectors have a second axial position, wherein the first and second axial positions alternate circumferentially around the scaffold.

[0180] Scaffold 700 also includes a second region that is axially adjacent a first region, wherein the second region comprises a plurality of peaks 724 that are shown oriented orthogonally relative to a long axis of the scaffold 700. In this example, each of the plurality of peaks 724 is an extension of one of the axially extending elements 721, as shown. Scaffold 700 also includes a third region that is axially adjacent the second region, the third region comprising a second plurality of linear axially extending elements as shown that are spaced apart around the scaffold, and a second plurality of circumferential connectors 722, where the second region joins the first region and third region. In this embodiment, the second region includes first convex section 725 and second convex section 727, connected at location 729.

[0181] Figures 25A and 25B illustrate an exemplary scaffold 750, which in this example includes a proximal scaffold 760, central scaffold 770 and distal scaffold 780, which are unitary. Scaffold 750 is similar in several ways to scaffold 700 in figures 24A and 24B, the disclosure of which is completely incorporated by reference in the description of figures 25 A and 25B, any features of which may be included in scaffold 750. One difference is that scaffold 750 central scaffold 770 includes a first region that includes peaks 774, wherein the first region includes sections 775 and 777 connected at location 779, wherein sections 775 and 777 create a smoother curvilinear region than sections 725 and 727 in scaffold 700. An additional difference is that scaffold 750 includes proximal and distal scaffolds that both include mirrored sections, such as sections 763 and 765 as shown in figure 25B. The mirrored aspect refers to axially adjacent connectors 762 in section 763 that are mirrored with respect to connectors 762 in section 765. The same mirrored aspect is shown in distal scaffold 780. The mirrored sections in proximal scaffold 760 are closer to central scaffold 770 than the mirrored sections in distal scaffold 780, as shown. In alternative embodiments, mirrored sections in a distal scaffold may be closer to a central scaffold than mirrored sections in a proximal scaffold. The description of all other aspects of scaffolds herein, including axially extending elements and circumferential connectors, are incorporated by reference herein into the scaffold 750. Figure 25B shows a flat expanded configuration, while figure 25A shows a flat non-expanded configuration.

[0182] Figures 26A and 26B illustrate scaffold 800, which as shown includes many of the same features as scaffold 750 shown in figures 25A and 25B. Figure 26A illustrate a flattened unexpanded configuration, while figure 26B illustrates transition region 801 of scaffold 800 called out in figure 26A. A difference between the scaffolds is that in figures 26A and 26B, proximal scaffold 810 includes mirrored sections that are further from central scaffold 820 than mirrored section in distal scaffold, as shown. Figure 26B illustrates a transition region between proximal scaffold 810 and central scaffold 820. Scaffold 800 includes orthogonally oriented peaks 824 as described elsewhere herein. Scaffold first regions includes sections 825 and 827, which may be the same as sections 775 and 777 in scaffold 750. Figure 26B illustrates the widths of axially extending elements 811 being greater than the widths of elements 821 in central scaffold, as shown. The thickness measurements are into the page in the figures (in the “z” direction), while the width measurements are in the plane of the page in the figures shown. One thickness “t” of element 811 is labeled for reference. As shown, the thickness “t” of element 811 is greater than the thickness of elements 821 in the central scaffold section.

[0183] Figures 27A and 27B illustrate exemplary scaffold 850, which is similar in several ways to scaffold 550 shown in figures 21A and 21B. Scaffold 850 includes proximal scaffold 860, central scaffold 870 and distal scaffold 880, which in this embodiment may be unitary. Scaffold 850 central scaffold 870 includes helical elements 871 in the non-collapsed configuration (fig 27 A) and the wrapped configuration (figure 27B). In this and any other embodiment herein the scaffold may be manufactured (e.g., including laser cutting of a tubular member) such that the expanded configuration is the configuration is which the scaffold is laser-cut from the tubular member. This is in contrast to any examples herein in which the scaffold is laser cut from a smaller diameter tubular member, and then expanded and set into an expanded configuration. In any of the embodiments herein, a laser cut diameter may be equal to a non-collapsed diameter to, for example without limitation, provide better concentricity. This may also allow coating of a membrane to adhere to struts and have a smoother inner diameter.

[0184] Proximal scaffold 860 and distal scaffold 880 have substantial the same configuration, but they are displaced circumferentially by circumferential spacing “CS” (labeled in figure 27 A). Adjacent helical elements 871 are connected by connectors 872. All other similar aspect of other scaffolds herein may be incorporated herein, including, by way of example only, the axially offset nature of circumferentially adjacent circumferential connectors in proximal scaffold 860 and distal scaffold 880.

[0185] Figure 27A illustrates exemplary distal and proximal struts extending axially from the scaffold, only one strut of which 865 is labeled. In this example there are four proximal and four distal struts. As shown, the struts are tapered and are wider at ends further from the scaffold, which may increase stability over the impellers compared to struts that have a constant width over their entire length. Any of the pump portions herein may include any number of struts that have the same configuration as struts 865.

[0186] In any of the embodiments herein, the scaffold may be cut from a tubular member that has an expanded scaffold diameter. In these embodiments, the tubular member has a diameter that is the same or substantially the same as the desired scaffold deployed configuration (un sheathed). Alternatively, in any of the embodiments herein, the scaffold may be cut from a tubular member that has a non-expanded scaffold diameter. In this embodiments, the tubular member has a diameter less than a scaffold expanded diameter, and after being cut the scaffold may be expanded set in the expanded deployed configuration.

[0187] In any of the embodiments herein, a distal scaffold may have a length that is greater than a length of a proximal scaffold. In any of the embodiments herein, a distal scaffold may have a length that is less than a length of a proximal scaffold. In any of the embodiments herein, a distal scaffold may have a length that is the same as a length of a proximal scaffold.

[0188] In any embodiment herein, a central scaffold may have a length that is greater than a length of one or both of a proximal scaffold and a distal scaffold.

[0189] Any of the different scaffold sections herein may be connected with one or more welds, and may not be unitary with each other.

[0190] In any of the embodiments herein, any section or sections of the scaffold may have a thickness (measured radially between a scaffold inner diameter and a scaffold outer diameter) that is the same as or different than a thickness of any other section of the scaffold. For example, a thickness of a scaffold section may be decreased by electropolishing one or more sections more than other sections (which may include no electropolishing). Varying the thickness may be in addition to or alternative to varying the width, which may allow for more design options, as may be desired.

[0191] In any of the embodiments herein, an axial distance between proximal and distal scaffold sections may be from 30 mm to 50 mm, such as from 35 mm to 45 mm. [0192] In any of the embodiments herein, the pump portion may be from 40 mm and 80 mm, such as from 50 mm to 70 mm, such as from 55 mm to 65 cm.

[0193] In any of the embodiments herein that include first and second impellers, an axial distance between impellers may be from 40 mm to 60 mm, such as from 45 mm to 55 mm.

[0194] In any of the embodiments herein, a diameter of the expanded (or non-collapsed) blood conduit may be from 6 mm to 8.5 mm, such as from 6 mm to 8 mm, such as from 6.5 mm to 7.5 mm

[0195] In any of the embodiments herein, a diameter of any of the impellers when expanded may be from 5 mm to 7 mm, such as from 5.5 mm to 6. 5 mm.

Claims

1. A catheter blood pump (“blood pump”), comprising: an expandable pump portion extending distally relative to a catheter, the pump portion including an impeller housing that includes an expandable blood conduit defining a blood lumen, and a plurality of expandable struts coupled to the expandable blood conduit, the expandable blood conduit including a proximal impeller scaffold, a distal impeller scaffold, and a central scaffold disposed between the proximal impeller scaffold and the distal impeller scaffold, the central scaffold being less stiff in response to a radially inward force than the proximal and distal impeller scaffolds, and a membrane coupled to the proximal impeller scaffold, the central scaffold, and the distal impeller scaffold, the membrane at least partially defining the blood lumen, and a proximal impeller disposed at least partially within the proximal impeller scaffold and a distal impeller disposed at least partially within the distal impeller scaffold.

2. The blood pump of claim 1, wherein the central scaffold is connected with at least one of the proximal impeller scaffold and the distal impeller scaffold.

3. The blood pump of Claim 2, wherein the central scaffold is connected with the proximal impeller scaffold and the distal impeller scaffold.

4. The blood pump of claim 3, wherein the central scaffold is unitary with the proximal impeller scaffold and the distal impeller scaffold.

5. The blood pump of claim 3, wherein the central scaffold is attached to the proximal impeller scaffold and attached to the distal impeller scaffold, optionally with welds.

6. The blood pump of any of claims 1-5, wherein the central scaffold has a configuration that is different than the proximal impeller scaffold and the distal impeller scaffold.

7. The blood pump of claim 6, wherein the proximal impeller scaffold and the distal impeller scaffold have the same or substantially the same configuration.

8. The blood pump of claim 7, wherein a dimension of a first feature of the proximal impeller scaffold is different than a corresponding feature of the distal impeller scaffold.

9. The blood pump of claim 6, wherein the proximal impeller scaffold and the distal impeller scaffold have different configurations.

10. The blood pump of any of claims 1-9, wherein the distal impeller scaffold has a length that is greater than a length of the proximal impeller scaffold.

11. The blood pump of any of claims 1-10, wherein the distal impeller has a length that is less than a length of the proximal impeller.

12. The blood pump of any of claims 1-11, wherein a width dimension of a central scaffold linear element is less than a width dimension of a proximal impeller scaffold linear element.

13. The blood pump of Claim 12, wherein the central scaffold linear element is axially linear.

14. The blood pump of Claim 12, wherein the central scaffold linear element is helically linear.

15. The blood pump of Claim 12, wherein the proximal impeller scaffold linear element is axially linear.

16. The blood pump of any of claims 12 - 15, wherein a width dimension of a central scaffold linear element is less than a width dimension of a distal impeller scaffold linear element.

17. The blood pump of any of Claims 1-12, wherein at least one of the proximal impeller scaffold and the distal impeller scaffold comprises a plurality of linear axially extending elements spaced apart around the blood conduit, wherein first and second adjacent linear axially extending elements are each connected by a circumferential connector having at least one bend formed therein, the circumferential connectors defining a plurality of circumferential connectors around the blood conduit, and wherein circumferentially adjacent circumferential connectors of the plurality of circumferential connectors are displaced axially relative to one another, and wherein each one of the linear axially extending elements connects adjacent circumferential connectors that are axially displaced.

18. The blood pump of claim 17, wherein a first group of the plurality of circumferential connectors have a first axial position, and wherein a second group of the plurality of circumferential connectors have a second axial position, wherein the first and second axial positions alternate circumferentially around the blood conduit.

19. The blood pump of claim 18, wherein the proximal impeller scaffold and the distal impeller scaffold each comprise a separate plurality of linear axially extending elements.

20. The blood pump of any of claims 1-19, wherein the central scaffold comprises a first region that comprises a plurality of linear axially extending elements spaced apart around the blood conduit, wherein first and second adjacent linear axially extending elements are each connected by a circumferential connector having at least one bend formed therein, the circumferential connectors defining a plurality of circumferential connectors around the blood conduit, and wherein circumferentially adjacent circumferential connectors of the plurality of circumferential connectors around the blood conduit are displaced axially relative to one another, and wherein each one of the linear axially extending elements connect adjacent circumferential connectors that are axially displaced.

21. The blood pump of claim 20, wherein the central scaffold further comprises a second region axially adjacent the first region, the second region comprising a plurality of peaks oriented orthogonally relative to a long axis of the blood conduit.

22. The blood pump of claim 21, wherein each of the plurality of peaks is an extension of one of the linear axially extending elements in the first region.

23. The blood pump of claim 21 or claim 22, further comprising a third region axially adjacent the second region, the third region comprising a second plurality of linear axially extending elements spaced apart around the blood conduit and a second plurality of circumferential connectors with the same relative configurations as is set forth in claim 20 the second region joining the first and third regions.

24. The blood pump of any of claims 21-23, wherein the second region further comprises a non- straight line between the peak and one of the linear axially extending elements.

25. The blood pump of claim 24 wherein the non-straight line comprises a plurality of convex sections separated by a bend in the scaffold.

26. The blood pump of claim 20, wherein the plurality of linear axially extending elements in the central scaffold have a width that is less than a width of the plurality of linear axially extending elements in the at least one of the proximal impeller scaffold and the distal impeller scaffold.

27. The blood pump of claim 26, wherein the plurality of linear axially extending elements in the central scaffold have a width that is less than a width of the plurality of linear axially extending elements in the proximal impeller scaffold and the distal impeller scaffold.

28. The blood pump of claim 27, wherein the width of the plurality of linear axially extending elements in the proximal impeller scaffold and the distal impeller scaffold is the same.

29. The blood pump of any of claims 17-28, wherein the at least one of the proximal impeller scaffold and the distal impeller scaffold comprises a second plurality of circumferential connectors that are mirrored with the plurality of circumferential connectors around the blood conduit.

30. The blood pump of claim 29, wherein the proximal impeller scaffold and the distal impeller scaffold each comprise a second plurality of mirrored circumferential connectors around the blood conduit.

31. The blood pump of claim 29, wherein the at least one of the proximal impeller scaffold and the distal impeller scaffold further comprises a third plurality of circumferential connectors that are not mirrored with the plurality of circumferential connectors.

32. The blood pump of any of claims 1-31, wherein a length of the proximal impeller scaffold is less than a length of the distal impeller scaffold.

33. The blood pump of claim 32, wherein a length of the distal impeller is less than a length of the proximal impeller.

34. The blood pump of claim 32, or claim 33, wherein the proximal impeller extends proximally out of the blood conduit.

35. The blood pump of any of claims 1-34, wherein the central scaffold includes a plurality of helical elements having a helical configuration between the proximal scaffold and the distal scaffold.

36. The blood pump of claim 35, wherein adjacent helical elements of the plurality of helical elements are connected by a plurality of axial connectors.

37. The blood pump of claim 36, wherein the plurality of axial connectors comprise an inflection point where the axial connectors transitions from convex to concave.

38. The blood pump of claim 35 or claim 36, wherein each of the helical elements is an extension of a linear axial element in at least one of the proximal scaffold or the distal scaffold.

39. The blood pump of claim 38, wherein each of the helical elements is an extension of a linear axial element in the proximal scaffold and is an extension of a linear axial element in the distal scaffold.

40. The blood pump of claim 39, wherein the linear axial elements in the proximal and distal scaffolds that extend from a first helical element are not circumferentially aligned.

41. The blood pump of any of claims 35 - 39, wherein the plurality of helical elements comprises more than two and less than fifteen helical elements.

42. The blood pump of any of claims 35 - 39, wherein the plurality of helical elements consists of four helical elements.

43. The blood pump of any of claims 1 - 41, wherein the proximal scaffold and the distal scaffold have the same or substantially the same configuration.

44. The blood pump of claim 43, wherein the distal scaffold is circumferentially offset relative to the proximal scaffold.

45. The blood pump of claim 44, wherein the distal scaffold is circumferentially offset between one and 90 degrees relative to the proximal scaffold.

46. The blood pump of any of claim 43 - 45, wherein first circumferential members in the distal scaffold are closer together than corresponding second circumferential members in the proximal scaffold.