Catheter blood pumps, and methods of use and manufacture

Abstract

To provide catheter blood pumps, and methods of use and manufacture.SOLUTION: Pumps 1600 may include an expandable and collapsible shroud that defines a blood lumen. The shroud may include a polymeric scaffold along at least a portion of a length of the shroud. The pumps 1600 may include one or more impellers 1606, 1616.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Incorporation by Reference

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 857,694, filed June 5, 2019, the entire contents of which are hereby incorporated by reference for all purposes.

[0002]

[0002] The present disclosure may be related to the disclosures from the following publications: WO2018 / 226991, WO2019 / 094963, WO2019 / 152875, and WO2020 / 028537, the entire contents of which are fully incorporated herein by reference for all purposes.

[0003]

[0003] All publications and patent applications mentioned in this specification are incorporated by reference herein to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. [Background technology]

[0004]

[0004] Patients with cardiac disease may have a significantly reduced ability to carry blood through the heart and vasculature, which may pose significant risks during corrective procedures such as balloon angioplasty and stent delivery. There is a need for techniques to improve the volume or stability of the cardiac outflow tract in these patients, particularly during corrective procedures.

[0005]

[0005] Intra-aortic balloon pumps (IABPs) are commonly used to support circulatory function, such as in treating patients with heart failure. The use of IABPs is common in treating patients with heart failure, such as supporting patients during high-risk percutaneous coronary intervention (HRPCI), stabilizing a patient's blood flow after cardiogenic shock, treating patients suffering from acute myocardial infarction (AMI), or treating decompensated heart failure. Such circulatory support can be utilized alone or in conjunction with pharmacological therapy.

[0006]

[0006] An IABP is typically placed in the aorta and functions by being inflated and deflated in a counter-pulsatile fashion relative to cardiac contraction, one of its functions being to provide additional support to the circulatory system. Summary of the Invention [Problem to be solved by the invention]

[0007]

[0007] More recently, minimally invasive rotary blood pumps have been developed that can be inserted into the body and connected to the cardiac system, such as to pump arterial blood from the left ventricle into the aorta to enhance the natural pumping capacity of the left side of a patient's heart. Another known method is to pump venous blood from the right ventricle to the pulmonary artery to enhance the natural pumping capacity of the right side of a patient's heart. The overall purpose is to reduce the workload of a patient's cardiac muscle and stabilize the patient, such as during a medical procedure that may place additional stress on the heart, to stabilize the patient before a heart transplant, or to provide continuous support to the patient.

[0008]

[0008] The smallest rotary blood pumps currently available can be inserted percutaneously into a patient's vasculature through an access sheath or through a vascular access graft to avoid the need for surgical intervention. The term for this type of device is a percutaneously inserted ventricular assist device.

[0009]

[0009] Additional improvements need to be achieved in the field of ventricular assist devices and similar blood pumps for treating reduced cardiac blood flow. [Means for solving the problem]

[0010]

[0010] The present disclosure relates to catheter blood pumps and methods of use and manufacture.

[0011] One aspect of the present disclosure is a catheter pump having an expandable and collapsible shroud defining a blood lumen, the shroud having a polymeric scaffold along at least a portion of the length of the shroud.

[0011]

[0012] The expandable and collapsible shroud may have a higher stiffness in the distal and proximal impeller regions than in a central shroud region between the distal and proximal impeller regions.

[0012]

[0013] The polymer scaffold can extend along the entire length or substantially the entire length of the shroud.

[0014] The polymer scaffold may not extend along the entire length of the shroud, but rather the polymer scaffold may extend around at least a portion of the impeller.

[0013]

[0015] The polymer scaffold can be a first polymer scaffold, and the shroud can include a second polymer scaffold unconnected to the first polymer scaffold and axially spaced from the first polymer scaffold. The second polymer scaffold can extend around at least a portion of the second impeller.

[0014]

[0016] The stiffness of the polymer scaffold may not be constant along its entire length. The polymer scaffold may have a higher stiffness in a first region around the impeller than in a second region that does not extend around the impeller. The polymer scaffold may have a higher stiffness in a third region around the second impeller than in the second region. The second region may be a central shroud region between the first and second impellers.

[0017] A polymer scaffold can extend along a central shroud region between the first and second impeller regions of the pump. The polymer scaffold can further extend at least partially into the first and second impeller regions. The polymer scaffold need not extend along the entire length of the first impeller region, and need not extend along the entire length of the second impeller region. The shroud can further include a metal scaffold in the first impeller region and a second metal scaffold in the second impeller region. The first and second metal scaffolds can be axially spaced apart but connected and part of the same scaffold.

[0015]

[0018] The shroud may be free or substantially free of metal support members. The shroud may be substantially free of metal support members, but the proximal end of the shroud may further comprise axial extensions of proximal metal struts, the proximal struts being collapsible and positioned and configured to facilitate folding of the shroud. The shroud may be substantially free of metal support members, but the distal end of the shroud may comprise axial extensions of distal metal struts, the distal struts being extends distally from the distal end of the shroud.

[0016]

[0019] The shroud can have a polymeric membrane at least partially defining the blood lumen, and the polymeric scaffold can have a stiffness greater than the stiffness of the polymeric membrane. The polymeric scaffold can have a durometer greater than the durometer of the polymeric membrane.

[0017]

[0020] The polymeric scaffold can have a variable stiffness along at least a portion of the length of the polymeric scaffold. The polymeric scaffold can have a region where the durometer of the polymeric scaffold changes from a first durometer to a second durometer.

[0018]

[0021] The shroud may further comprise one or more metal support members, with the polymer scaffold covering a greater area than the one or more metal support members between the shroud distal end and the shroud proximal end.

[0019]

[0022] The polymeric scaffold may have a durometer value at least 10 units greater on the Shore hardness scale than the shroud member. The polymeric scaffold may have a durometer value at least 20 units greater on the Shore hardness scale than the shroud membrane. The polymeric scaffold may have a durometer value at least 30 units greater on the Shore hardness scale than the shroud membrane.

[0020]

[0023] The polymer scaffold can include a plurality of spaced apart elongated elements that can extend around and / or along at least a portion of the shroud. The polymer scaffold can extend the entire periphery of the shroud. The first and second elongated elements can contact each other integrally or can be separate elements connected within the upper / lower surfaces.

[0021]

[0024] A central region of the shroud may comprise a polymeric scaffold, the central region having greater flexibility than proximal and distal shroud impeller regions spaced axially from the central region.

[0022]

[0025] A central region of the shroud may have a greater flexibility than proximal and distal shroud impeller regions spaced axially from the central region.

[0023]

[0026] One aspect of the disclosure is a catheter pump comprising: an expandable and collapsible shroud defining a blood lumen; an expandable and collapsible scaffold, the scaffold comprising a first portion having an expanded configuration and a second portion having an expanded configuration, the second portion axially spaced from the first portion, the second portion having a maximum outer dimension smaller than the maximum outer dimension of the first portion, the shroud comprising the first portion; and a pump outflow between the first portion and the second portion.

[0024]

[0027] One aspect of the present disclosure is a catheter pump having an expandable and collapsible shroud defining a blood lumen; and an expandable scaffold axially spaced from the shroud, the expandable scaffold having a maximum outer dimension that is smaller than a maximum outer dimension of the shroud. and a pump outlet is disposed between the shroud and the expandable scaffold. [Brief explanation of the drawings]

[0025] [Figure 1]

[0028] FIG. 1 is a side view illustrating an example pump having an expandable and collapsible shroud and multiple expandable and collapsible impellers. [Figure 2]

[0029] FIG. 10 is a side view illustrating an example pump having an expandable and collapsible shroud and multiple expandable and collapsible impellers, where the shroud has axially spaced scaffolds. [Figure 3A]

[0030] 1A-1C illustrate an exemplary pump having an expandable and collapsible shroud and multiple expandable and collapsible impellers, where the shroud has axially spaced scaffolds. [Figure 3B] 1A-1C illustrate an exemplary pump having an expandable and collapsible shroud and multiple expandable and collapsible impellers, where the shroud has axially spaced scaffolds. [Figure 3C] 1A-1C illustrate an exemplary pump having an expandable and collapsible shroud and multiple expandable and collapsible impellers, where the shroud has axially spaced scaffolds. [Figure 3D] 1A-1C illustrate an exemplary pump having an expandable and collapsible shroud and multiple expandable and collapsible impellers, where the shroud has axially spaced scaffolds. [Figure 4]

[0031] 1A-1C illustrate exemplary placement of a catheter pump. [Figure 5]

[0032] FIG. 1 shows a pump section with multiple impellers. [Figure 6]

[0033] FIG. 1 is a side view of a pump having a central or intermediate member axially spaced between a first impeller and a second impeller. [Figure 7A]

[0034] 1A-1C illustrate an exemplary pump portion having an expandable housing or shroud with an exemplary scaffold configuration. [Figure 7B] 1A-1C illustrate an exemplary pump portion having an expandable housing or shroud with an exemplary scaffold configuration. [Figure 7C] 1A-1C illustrate an exemplary pump portion having an expandable housing or shroud with an exemplary scaffold configuration. [Figure 7D] 1A-1C illustrate an exemplary pump portion having an expandable housing or shroud with an exemplary scaffold configuration. [Figure 8]

[0035] FIG. 1 illustrates an exemplary scaffold configuration. [Figure 9]

[0036] FIG. 1 illustrates an exemplary scaffold configuration. [Figure 10]

[0037] FIG. 1 illustrates an exemplary scaffold configuration. [Figure 11A]

[0038] 1A-1C illustrate an exemplary method of positioning an exemplary blood pump. [Figure 11B] 1A-1C illustrate an exemplary method of positioning an exemplary blood pump. [Figure 11C] 1A-1C illustrate an exemplary method of positioning an exemplary blood pump. [Figure 11D] 1A-1C illustrate an exemplary method of positioning an exemplary blood pump. [Figure 11E] 1A-1C illustrate an exemplary method of positioning an exemplary blood pump. [Figure 11F] 1A-1C illustrate an exemplary method of positioning an exemplary blood pump. [Figure 12A]

[0039] 1A-1C illustrate a portion of an example shroud, where the shroud can have a polymer scaffold. [Figure 12B] 1A-1C illustrate a portion of an example shroud, where the shroud can have a polymer scaffold. [Figure 13A]

[0040] 1A-1C illustrate a portion of an example shroud, where the shroud can have a polymer scaffold. [Figure 13B] 1A-1C illustrate a portion of an example shroud, where the shroud can have a polymer scaffold. [Figure 14]

[0041] 1 illustrates an exemplary end of a shroud having struts extending therefrom. [Figure 15]

[0042] FIG. 1 illustrates a portion of a catheter pump having first and second expandable scaffold portions having different maximum radial dimensions with a pump outflow between the two portions. DETAILED DESCRIPTION OF THE INVENTION

[0026]

[0043] The present disclosure relates to medical devices, systems, and methods of use and manufacture. The medical devices herein can have a distal pump portion (which may also be referred to herein as an working portion) adapted for placement within a physiological vessel, the distal pump portion having one or more components that act on a fluid. For example, the distal pump portion herein can have one or more rotating members that, when rotated, can promote the movement of a fluid, such as blood.

[0027]

[0044] Any disclosure of the present specification relating to the aspects of a system, a device, or a method of use can be incorporated into any other appropriate disclosure of the present specification.For example, a diagram illustrating only one aspect of a device or a method can be included in other embodiments even if it is not specifically described in the description of one or any part of the present disclosure.Therefore, it should be understood that the combination of different parts of the present disclosure is included in the present specification unless otherwise specified.

[0028]

[0045] FIG. 1 is a side view illustrating the distal portion of an exemplary intravascular fluid pump having a pump portion 1600 having a proximal impeller 1606 and a distal impeller 1616, both of which are operably connected to a drive cable 1612. While the pump portion 1600 is shown in its expanded configuration in FIG. 1 , it is adapted to collapse into its delivery configuration so that it can be delivered in a low profile. The impellers may be attached to the drive cable 1612. The drive cable 1612 is operably connected to an external motor (not shown) and extends through an elongated shaft 1610. The phrases “pump portion” and “working portion” (or derivatives thereof) may be used interchangeably herein unless otherwise indicated. For example, and without limitation, the “pump portion” 1600 may be referred to herein as the “working portion.”

[0029]

[0046] The pump portion 1600 further includes an expandable member 1602, which in this embodiment has a proximal end 1620 extending proximally beyond the proximal end of the proximal impeller 1606 and a distal end 1608 extending distally beyond the distal end of the distal impeller 1616. The expandable member 1602 is disposed radially outward of the impeller along the axial length of the impeller. The expandable member 1602 may be constructed in a manner similar to, and made from materials similar to, many types of expandable structures known in the medical arts to be collapsible and expandable. Examples of these approaches or methods are provided herein. Examples of suitable materials include, but are not limited to, polyurethane and polyurethane elastomers.

[0030]

[0047] The pump portion 1600 further includes a conduit 1604 coupled to the expandable member 1602, the expandable member 1602 having a length L and extending axially between the impellers. The conduit 1604 forms and provides a fluid lumen between the two impellers. In use, fluid travels through the lumen provided by the conduit 1604. The conduits herein may be impermeable, or may be semi-permeable or even porous so long as they are capable of defining a lumen. Also, unless otherwise specified, the conduits herein are flexible. The conduits herein extend completely (i.e., 360 degrees) around at least a portion of the pump portion. Within the pump portion 1600, the conduit extends completely around the expandable member 1602, but does not extend to the proximal end 1602 or the distal end 1608 of the expandable member 1602. The structure of the expandable member includes at least one conduit for allowing inflow "I". It creates an inlet aperture and at least one outlet aperture to allow for outlet "O." The conduit 1604 improves the dynamics of the pumping of the impeller compared to the dynamics that the working part 1600 would have without the conduit.

[0031]

[0048] The expandable member 1602 can have a variety of configurations and can be made from a variety of materials. For example, the expandable member 1602 can be formed like an expandable stent or stent-like device, or like any other example provided herein. For example, and without limitation, the expandable member 1602 can have an open braided configuration, such as a 24-end braid. However, more or fewer braided wires can be used. Exemplary materials for the expandable member include nitinol, cobalt alloys, and polymers. However, other materials can be used. The expandable member 1602 has an expanded configuration as shown, where the outermost dimension of the expandable member (measured perpendicular to the longitudinal axis of the working portion) is greater at least in regions where the expandable member is disposed radially outward of the impellers than the outermost dimension of a central region 1622 of the expandable member that extends axially between the impellers. The drive cable 1612 is coaxial with the longitudinal axis in this embodiment. In use, the central region can be positioned to span a valve, such as the aortic valve. In some embodiments, the expandable member 1602 is adapted and constructed to expand to an outermost dimension of 12-24 F (4.0-8.0 mm) where the impellers reside axially within the expandable member, and to an outermost dimension of 10-20 F (3.3-6.7 mm) in the central region 1622 between the impellers. The smaller outer dimension of the central region can reduce forces acting on the valve, thereby reducing or minimizing damage to the valve. The larger dimension of the expandable member in the impeller region can help axially stabilize the working portion during use. The expandable member 1602 has a general dumbbell configuration. The expandable member 1602 has an outer configuration that tapers from the impeller region to the central region 1622 and also tapers at the distal and proximal ends of the expandable member 1602.

[0032]

[0049] The expandable member 1602 has a proximal end 1620 coupled to a shaft 1610 and a distal end 1608 coupled to a distal tip 1624. An impeller and drive cable 1612 rotates within the expandable member and conduit assembly. The drive cable 1612 is axially stabilized relative to the distal tip 1624 but is free to rotate relative to the distal tip 1624.

[0033]

[0050] In some embodiments, the expandable member 1602 can be collapsed by pulling tension across the expandable member. This can include a linear movement that stretches the expandable member 1602 axially (e.g., but not limited to, moving 5-20 mm) until the expandable member 1602 assumes a collapsed configuration with the collapsed outer dimensions. The expandable member 1602 can also be collapsed by pushing an outer shaft, such as a sheath, over the expandable member / conduit assembly, thereby collapsing the expandable member and conduit into a collapsed delivery configuration.

[0034]

[0051] Impellers 1606 and 1616 are also adapted and constructed to stretch or radially compress one or more blades to a reduced outermost dimension (measured perpendicular to the longitudinal axis of the working portion). For example, without limitation, any of the impellers herein can have one or more blades made from a plastic compound having spring properties, such as any of the impellers described in U.S. Pat. No. 7,393,181. The disclosure of U.S. Pat. No. 7,393,181 is incorporated herein by reference and may be incorporated into embodiments herein unless otherwise indicated by this disclosure. Alternatively, for example, one or more foldable impellers may be constructed as described in U.S. Pat. No. 6,533, the disclosure of which is incorporated herein by reference. The device may comprise a superelastic wire frame, such as that described in US Pat. No. 6,716, having a polymer or other material acting as webbing that crosses the wire frame.

[0035]

[0052] The inflow and / or outflow configuration of the working portion 1600 may be predominantly axial in nature.

[0053] Exemplary sheathing and unsheathing techniques and concepts for folding and expanding medical devices are known, such as 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 herein by reference.

[0036]

[0054] 2 is a side view illustrating a deployed configuration (shown outside the body) of a distal portion of an exemplary embodiment of a fluid transfer system. The exemplary system 1100 has a working portion 1104 (which may also be referred to herein as a pump portion, as described herein) and an elongated portion 1106 extending from the working portion 1104. The elongated portion 1106 may extend to a more proximal region of the system, not shown for simplicity; this more proximal region may include a motor, for example. The working portion 1104 has a first expandable member 1108 and a second expandable member 1110 that are axially spaced apart along the longitudinal axis LA of the working portion 1104. Axially spaced apart in this context means that the entire first expandable member is axially spaced apart from the entire second expandable member along the longitudinal axis LA of the working portion 1104. A first end 1122 of the first expansible member 1108 is axially spaced from a first end 1124 of the second expansible member 1110 .

[0037]

[0055] The first expandable member 1108 and the second expandable member 1110 each generally have a plurality of elongated segments arranged relative to one another to define a plurality of apertures 1130. Only one aperture of the plurality of apertures 1130 in the second expandable member 1110 is labeled with a reference number. The expandable members can have a wide variety of configurations and can be constructed in a wide variety of ways, such as, but not limited to, any of the configurations or constructions of U.S. Pat. No. 7,841,976 or the tubing of U.S. Pat. No. 6,533,716, which is described as a self-expanding metallic endoprosthetic material. For example, but not limited to, one or both of the expandable members can have a braided configuration or can be formed at least in part by laser cutting a tubular element.

[0038]

[0056] The working portion 1104 further includes a conduit 1112 coupled to the first and second expandable members 1108 and 1110 and extending axially between them in the deployed configuration. A central region 1113 of the conduit 1112 spans an axial distance 1132, where the working portion does not include the first and second expandable members 1108 and 1110. The central region 1113 may be considered to be axially between the expandable members. The distal end 1126 of the conduit 1112 does not extend distally as far as the distal end 1125 of the second expandable member 1110, and the proximal end 1128 of the conduit does not extend proximally as far as the proximal end 1121 of the first expandable member 1108.

[0039]

[0057] When the disclosure herein refers to a conduit coupled to an expandable member, the term coupled in this context does not require that the conduit be directly attached to the expandable member such that the conduit is in physical contact with the expandable member. However, even if not directly attached, the term coupled in this context may still be used to refer to a conduit that is in physical contact with the expandable member, whether the expandable member is expanded or not. It means that the conduit and the expandable member are joined together such that when the conduit is expanded or collapsed, the conduit will also begin to transition to a different configuration and / or size. Thus, coupled in this context means that the conduit will move when the expandable member connecting the conduit transitions between the expanded and collapsed configurations.

[0040]

[0058] Any of the conduits herein may be deformable to some extent. For example, the conduit 1112 has an elongate member 1120 that may be made of one or more materials that allow the central region 1113 of the conduit to deform radially inward (toward the LA) to some extent when the working portion 1104 is deployed toward the configuration shown in FIG. 2 , e.g., in response to forces from the valve tissue (e.g., leaflets) or replacement valve in use. In some embodiments, the conduit may be stretched rigidly between the expandable members. Alternatively, the conduit may be designed to have slack to improve compliance. This may be desirable when the working portion is positioned across a fragile structure, such as the aortic valve, allowing the valve to compress the conduit in a manner that minimizes point stresses within the valve. In some embodiments, the conduit may have a membrane attached to the proximal and distal expandable members. Exemplary materials that may be used for any of the conduits herein include, but are not limited to, polyurethane rubber, silicone rubber, acrylic rubber, expanded polytetrafluoroethylene, polyethylene, polyethylene terephthalate, including any combination thereof.

[0041]

[0059] Any of the conduits herein can have a thickness of 127 to 508 μm (5 to 20 thousandths of an inch (thou)), for example, from 25.4 μm (1 thou) to 381 μm (15 thou), from 38.1 μm (1.5 thou) to 381 μm (15 thou), from 38.1 μm (1.5 thou) to 254 μm (10 thou), or from 50.8 μm (2 thou) to 254 μm (10 thou).

[0042]

[0060] Any of the conduits herein, or at least a portion of a conduit, may be impermeable to blood. In FIG. 2, working portion 1104 has a lumen that extends from distal end 1126 of conduit 1112 to proximal end 1128 of conduit 1112. This lumen is defined by conduit 1112 in central region 1113, but in regions axially adjacent central region 1113, it may be considered to be defined by both the conduit and a portion of the expandable member. However, in this embodiment, it is the material of the conduit that causes the lumen to exist, and this material of the conduit also prevents blood from passing through the conduit.

[0043]

[0061] Any of the conduits herein secured to one or more expandable members, unless otherwise indicated, may be secured such that the conduit is disposed radially outward of the one or more expandable members, or radially inward of the one or more expandable members, or both, and the expandable members may be filled with the conduit material.

[0044]

[0062] The proximal and distal expandable members help maintain the conduit in an open configuration to create the lumen, while also creating an operating environment for the impellers, as described below. In the deployed configuration, each of the expandable members is maintained in a spaced-apart relationship relative to its respective impeller, thereby allowing the impellers to rotate within the expandable member without contacting the expandable member. The working portion 1104 has a first impeller 1116 and a second impeller 1118, with the first impeller 1116 radially disposed within the first expandable member 1108 and the second impeller 1118 radially disposed within the second expandable member 1110. In this embodiment, the two impellers, although separate and distinct, are operably connected to a common drive feature (e.g., drive cable 1117) such that the two impellers rotate in unison when the drive feature is actuated. In this deployed configuration, the axially Just as the expansible members 1108 and 1110 are spaced apart in the axial direction, the impellers 1116 and 1118 are spaced apart axially along the longitudinal axis LA.

[0045]

[0063] Impellers 1116 and 1118 also reside axially within the ends of expandable members 1108 and 1110, respectively (in addition to being radially within expandable members 1108 and 1110). Impellers herein may be considered to reside axially within the expandable members even if the expandable members have struts (e.g., struts that are tapered in side view) that extend from a central region of the expandable member toward the longitudinal axis of the working portion. In FIG. 2, second expandable member 1110 extends from a first end 1124 (proximal end) to a second end 1125 (distal end).

[0046]

[0064] In Figure 2, a distal portion of impeller 1118 extends distally beyond a distal end 1126 of conduit 1112, and a proximal portion of impeller 1116 extends proximally beyond a proximal portion 1128 of conduit 1112. In this illustration, a portion of each impeller resides axially within the conduit in this deployment configuration.

[0047]

[0065] In the exemplary embodiment shown in FIG. 2 , the impellers 1116 and 1118 are operably connected to a common drive feature 1117; in this embodiment, each of the impellers is coupled to a drive mechanism 1117 that extends through the shaft 1119 and the working portion 1104. The drive feature 1117 may be, for example, an elongated drive cable that, when rotated, also rotates the impellers. In this example, as shown, the drive mechanism 1117 extends to the distal tip 1114 and is axially fixed relative to the distal tip 1114, but the drive mechanism 1117 is also adapted to rotate relative to the distal tip 1114 upon actuation. Thus, in this embodiment, when the drive mechanism 1117 rotates, the impellers and the drive mechanism 1117 rotate in unison. Any number of known mechanisms may be used to rotate the drive features, such as mechanisms that use a motor (e.g., an external motor).

[0048]

[0066] The expandable member and conduit are not connected to the impeller and drive mechanism in a manner that allows for rotational movement. In this embodiment, the proximal end 1121 of the proximal expandable member 1108 is coupled to a shaft 1119, which may be the shaft of the elongated portion 1106 (e.g., an outer catheter shaft). The distal end 1122 of the proximal expandable member 1108 is coupled to a central tubular member 1133, through which the drive mechanism 1117 extends. The central tubular member 1133 extends distally from the proximal expandable member 1108 within the conduit 1112 and is further coupled to the proximal end 1124 of the distal expandable member 1110. Thus, the drive mechanism 1117 rotates within and relative to the central tubular member 1133. A central tubular member 1133 extends axially from the proximal expandable member 1108 to the distal expandable member 1110. The distal end 1125 of the distal expandable member 1110 is coupled to the distal end 1114 as shown. A drive mechanism 1117 is adapted to rotate relative to the tip 1114 but is fixed axially relative to the tip 1114.

[0049]

[0067] The working portion 1104 is adapted and configured to collapse to a smaller profile than its deployed configuration (shown in FIG. 2). This allows the working portion 1104 to be delivered using a lower profile delivery device (smaller French size) than would be necessary if the working portion 1104 were not collapsible. Even if not specifically described herein, any expandable member and impeller may be adapted and configured to be collapsible to some degree to a smaller delivery configuration.

[0050]

[0068] The working portion herein uses an outer sheath that is movable relative to the working portion. The sheath may be folded into the collapsed delivery configuration using conventional techniques (e.g., by axially moving one or both of the sheath and working portion), such as by using a conventional technique such as a technique described in the following references: U.S. Pat. No. 7,841,976 or U.S. Pat. No. 8,052,749, the disclosures of which are incorporated herein by reference.

[0051]

[0069] Figures 3A-3E show an exemplary working portion similar in some respects to the working portion shown in Figure 2. Working portion 340 is similar to working portion 1104 in that it has two expandable members that are axially spaced apart from one another when the working portion is expanded, and a conduit extending between the two expandable members. Figure 3A is a perspective view, Figure 3B is a side cross-sectional view, and Figures 3C and 3D are enlarged side cross-sectional views of the cross-section of the view of Figure 3B.

[0052]

[0070] The working portion 340 has a proximal impeller 341 and a distal impeller 342, which are coupled and operably connected to a drive cable, which defines a lumen therein. The lumen can be sized to accommodate a guidewire that can be used to deliver the working portion to a desired location. The drive cable, in this embodiment, has a first section 362 (e.g., a coiled material), a second section 348 (e.g., a tubular member) that couples the proximal impeller 341, a third section 360 (e.g., a coiled material), and a fourth section 365 (e.g., a tubular member) that couples the distal impeller 342. All of these drive cable sections have the same inner diameter, resulting in a constant lumen diameter. These drive cable sections can be secured to one another using known attachment techniques. The distal end of the fourth section 365 extends to a distal region of the working portion, thereby allowing the working portion to be advanced, for example, over a guidewire, to position the working portion. In this embodiment, the second and fourth sections may have a higher stiffness than the first and third sections. For example, the second and fourth sections may be tubular, and the first and third sections may be of rolled material to reduce stiffness.

[0053]

[0071] Working portion 340 has proximal and distal expandable members 343 and 344, each extending radially outward from one of the impellers. The expandable members have distal and proximal ends that may extend axially beyond the distal and proximal ends of the impellers, as can be seen in FIGS. 3B-3D . A conduit 356 is coupled to the two expandable members, the conduit 356 having proximal and distal ends 353 and 352. Each of the two expandable members has a plurality of proximal and distal struts. The proximal struts in proximal expandable member 343 extend to and are secured to shaft section 345, which is coupled to bearing 361, through which a drive cable extends and is configured and dimensioned to rotate. The distal struts of the proximal expandable member 343 extend to and are anchored to a proximal region (in this case, the proximal end) of the central tubular member 346, with the central tubular member 346 axially disposed between the expandable members. The proximal end of the central tubular member 346 is coupled to a bearing 349, as shown in FIG. 3C, through which a drive cable extends and rotates. The proximal struts of the distal expandable member 344 extend to and are anchored to a distal region (in this case, the distal end) of the central tubular member 346. Furthermore, a bearing 350 is coupled to the distal region of the central tubular member 346, as shown in FIG. 3D. The drive cable extends through and rotates relative to the bearing 350. The distal struts of the distal expansible member extend to and are secured to shaft section 347 (see FIG. 3A) and form a shaft. Shaft section 347 may be considered part of the distal end. Shaft section 347 is coupled to bearing 351 (see FIG. 3D), through which the drive cable extends and rotates. The distal tip further includes bearing 366 (see FIG. 3D), which may be a thrust bearing. Working portion 340 may be similar or identical to working portion 1104 in some respects, even if not explicitly included in this description. In this embodiment, conduit 356 extends at least as far as the end of the impeller, unlike working portion 1104. Either embodiment may be modified to extend the conduit to the position described in other embodiments. In some embodiments, section 360 may be a tubular section instead of being coiled.

[0054]

[0072] In alternative embodiments, at least a portion of any of the impellers herein extends outside the fluid lumen. For example, only a portion of the impeller may extend proximally or distally beyond the end of the fluid lumen. In some embodiments, the portion of the impeller that extends outside the fluid lumen is the proximal portion of the impeller and has a proximal end (see, e.g., the proximal impeller in FIG. 2). In some embodiments, the portion of the impeller that extends outside the fluid lumen is the distal portion of the impeller and has a distal end (see, e.g., the distal impeller in FIG. 2). When the disclosure herein refers to an impeller extending outside (i.e., beyond) the fluid lumen, this is intended to refer to the relative axial positions of the components as most easily seen in a side or top view, such as in FIG. 2.

[0055]

[0073] However, a second impeller at another end of the fluid lumen may not extend beyond the fluid lumen. For example, an exemplary alternative design may have a proximal impeller (similar to the proximal impeller of FIG. 2) that extends proximally beyond the proximal end of the fluid lumen, and the fluid lumen does not extend distally beyond the distal end of the distal impeller (as in FIG. 3). Alternatively, the distal end of the distal impeller may extend distally beyond the distal end of the fluid lumen, but the proximal end of the proximal impeller does not extend proximally beyond the proximal end of the fluid lumen. In any of the pump sections herein, none of the impellers may extend beyond the end of the fluid lumen.

[0056]

[0074] Although specific example locations may be shown herein, the fluid pump may be usable in a wide variety of locations within the body. Some example locations for placement include near the aortic or pulmonary valve, such as spanning the valve and being located on one or both sides of the valve, and in the case of the aortic valve, optionally including a portion located within the ascending aorta. In some other embodiments, for example, the pump may be located further downstream in use, such as in the descending aorta.

[0057]

[0075] FIG. 4 shows an example placement of the working portion 1104 from the system 100 of FIG. 2. One difference shown in FIG. 4 is that the conduit extends at least as far as the end of the impeller as in FIGS. 3A-3D. FIG. 4 shows the working portion 1104 in a deployed configuration, positioned in place to span the aortic valve. The working portion 1104 can be delivered, as shown, for example, but not limited to, via femoral artery access (a known access procedure). Although not shown for simplicity, the system 100 can further include an outer sheath or shaft within which the working portion 1104 is positioned during delivery to a location near the aortic valve. The sheath or shaft can be moved proximally (toward the ascending aorta "AA" and away from the left ventricle "LV"), thereby allowing the working portion 1104 to deploy and expand. For example, the sheath may be retracted to allow the second expandable member 1110 to expand, and continued proximally to allow the first expandable member 1108 to expand. To do so.

[0058]

[0076] In this embodiment, the second expandable member 1110 is expanded and positioned in a deployed configuration such that the distal end 1125 is within the left ventricle "LV," distal to the aortic valve leaflets "LV," and distal to the annulus. Furthermore, the proximal end 1124 is positioned distal to the leaflets "VL." However, in some embodiments, the proximal end 1124 may extend axially slightly within the leaflets VL. This embodiment is an example of a method in which at least half of the second expandable member 1110 resides within the left ventricle when measured along its length (measured along the longitudinal axis). Furthermore, as shown, this is also an example of a method in which the entire second expandable member 1110 resides within the left ventricle. This is also an example of a method in which at least half of the second impeller 1118 is positioned within the left ventricle, and even an embodiment in which the entire second impeller 1118 is positioned within the left ventricle.

[0059]

[0077] Continued retraction of the outer shaft or sheath (and / or distal movement of the working end 1104 relative to the outer sheath or shaft) continues to release the conduit 1112 until the central region 113 is released and deployed. The expansion of the expandable members 1108 and 1110 causes the conduit 1112 to assume a more open configuration, as shown in FIG. 4. Thus, in this embodiment, the conduit 1112 does not have the same self-expanding properties as the expandable members, but deployment of the working end causes the conduit to assume a more open, deployed configuration. At least a portion of the central region 1113 of the conduit 1112 is located at the coaptation region with the aortic valve. In FIG. 3, there is a short length of the central region 1113 that extends distally beyond the leaflets VL, but at least a portion of the central region 1113 resides axially within the leaflets.

[0060]

[0078] Continued retraction of the outer shaft or sheath (and / or distal movement of the working end 1104 relative to the outer sheath or shaft) deploys the first expandable member 1108. In this embodiment, the first expandable member 1108 is expanded and placed in a deployed configuration (as shown) such that the proximal end 1121 resides within the ascending aorta AA and is proximal to the leaflet "LV." Additionally, although the distal end 1122 is positioned proximal to the leaflet VL, in some methods the distal end 1122 may extend axially slightly within the leaflet VL. This embodiment is an example of a method in which at least half of the first expandable member 1110 resides within the ascending aorta when measured along its length (measured along the longitudinal axis). Additionally, as shown, this is also an example of a method in which the entire first expandable member 1110 resides within the AA. This is also an example of a method in which at least half of the first impeller 1116 is disposed within the AA, and even an embodiment in which the entire first impeller 1116 is disposed within the AA.

[0061]

[0079] At any time during or after deployment of the working portion 1104, the position of the working portion can be accessed by any technique, such as under fluoroscopy. The position of the working portion can be adjusted at any time during or after deployment. For example, the working portion 1104 can be moved axially (distally or proximally) after the second expandable member 1110 is released but before the first expandable member 1108 is released, thereby repositioning the working portion. In addition, the working portion can be repositioned, for example, after the entire working portion has been released from the sheath and reached a desired final position.

[0062]

[0080] It should be understood that the positions of the components shown in FIG. 4 (relative to the anatomy) are to be considered as exemplary final positions for the various components of the working portion 1104, even if repositioning occurs after initial deployment.

[0063]

[0081] One or more of the expandable members herein may be configured to and may be expanded in a variety of ways, such as by self-expanding, by mechanical actuation (e.g., by one or more axial forces exerted on the expandable member, by using a separate balloon radially disposed within the expandable member that expands to push the expandable member radially outward, etc.), or a combination thereof.

[0064]

[0082] As used herein, expansion generally refers to a reconfiguration to a larger profile having a larger outermost radial dimension (relative to the longitudinal axis), regardless of the specific manner in which one or more components are expanded. For example, a stent that self-expands and / or is subjected to an outward radial force may "expand," as the term is used herein. A device that unfolds or unfolds may assume a larger profile and may be considered to expand, as the term is used herein.

[0065]

[0083] The impellers may similarly be adapted and configured to expand in a variety of ways depending on their configuration. For example, when one or more impellers are released from the sheath, they may automatically return to or toward another larger-profile configuration due to the materials and / or configuration of the impeller's design (see, e.g., U.S. Pat. No. 6,533,716 or U.S. Pat. No. 7,393,181, both of which are incorporated herein by reference). Thus, in some embodiments, retracting the outer restraint allows both the expansible member and impellers to naturally return to their larger-profile deployed configurations without any other actuation.

[0066]

[0084] As shown in the embodiment of FIG. 4, the working portion has first and second spaced-apart impellers on either side of the aortic valve, each disposed within a separate expandable member. This contrasts with some designs in which the working portion has a single, elongated expandable member. Rather than a single, generally tubular expandable member spanning the entire valve, the working portion 1104 has a conduit 1112 extending between the expandable members 1108 and 1110. The conduit has greater flexibility and deformability than the expandable basket, thereby allowing for greater deformation of the working portion at the location of the aortic valve leaflets, as occurs when the expandable member extends across the leaflets. This can reduce damage to the leaflets after the working portion is deployed within the subject.

[0067]

[0085] Additionally, forces exerted by the leaflets on the central region of a single expandable member can translate axially to other regions of the expandable member, potentially causing undesired deformation of the expandable member at the location of one or more impellers. This can cause the outer expandable member to contact the impeller, thereby undesirably interfering with the rotation of the impeller. A design with separate expandable members around each impeller, and particularly one in which each expandable member and impeller is supported at both ends (i.e., distal and proximal), allows for a high level of precision in positioning the impellers relative to the expandable member. Two separate expandable members may be able to maintain their deployed configuration more reliably than a single expandable member.

[0068]

[0086] As discussed herein above, it may be desirable to be able to reconfigure the working portion so that it can be delivered into a 9F sheath and achieve sufficient flow rates in use that are not possible with some current products during deployment and / or testing. For example, some products may be designed to result in a sufficiently small delivery profile. 1, 2, 3A-3D, and 4, the first and second impellers may be too large to be reconfigured in this manner, while some smaller designs may not be able to achieve the desired high flow rates. Illustrative advantages of the embodiments of Figures 1, 2, 3A-3D, and 4 are that, for example, the first and second impellers can work together to achieve the desired flow rate, and by having two axially spaced impellers, the entire working section can be reconfigured to a smaller delivery profile than designs that use a single impeller to achieve the desired flow rate. Thus, these embodiments use multiple axially spaced smaller, reconfigurable impellers to achieve both the desired small delivery profile and the desired high flow rate.

[0069]

[0087] Thus, embodiments herein can achieve a small delivery profile while maintaining a sufficiently high flow rate, while creating a more deformable and flexible central region of the working portion, exemplary benefits of which are described above (e.g., cooperative contact with vulnerable valve leaflets).

[0070]

[0088] Any of the conduits herein may function, be configured, and be made of materials 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 out through the outflow region. Flow into the inflow may be designated herein by an "I," and flow into the outflow may be designated herein by an "O." Any of the conduits herein may be impermeable. Any of the conduits herein may alternatively be semi-permeable. Any of the conduits herein may be porous but still define a fluid lumen therethrough. In some embodiments, the conduit is a membrane or other relatively thin layered member. Unless otherwise indicated, any of the conduits herein may be secured to an expandable member such that the conduit may reside radially inside and / or outside the expandable member when secured. For example, the conduit may extend radially within the expandable member such that an inner surface of the conduit resides radially within the expandable member when secured to the expandable member.

[0071]

[0089] Any of the expandable members herein can be constructed of a variety of materials and in a variety of ways. For example, the expandable member can have a mesh configuration or can be formed by laser machining. The material can be deformable, such as Nitinol. The material can be deformable, such as Nitinol. The expandable member can be self-expanding or adapted to at least partially actively expand.

[0072]

[0090] In some embodiments, the expandable member is adapted to self-expand when released from within a containing tubular member, such as a delivery catheter, guide catheter, or access sheath. In some alternative embodiments, the expandable member is adapted to expand by active expansion, such as actuation of a pull rod to move at least one of the distal and proximal ends of the expandable member toward each other. In alternative embodiments, the deployed configuration may be influenced by the configuration of one or more expandable structures. In some embodiments, one or more expandable members may be deployed, at least in part, by the influence of blood flowing through the conduit. Any combination of the above expansion mechanisms may be used.

[0073]

[0091] The blood pump and fluid movement devices, systems, and methods herein may be used in and placed in a variety of locations within the body, and although specific examples may be presented herein, it should be understood that the working portions may be placed in regions within the body different from those specifically described herein.

[0074]

[0092] In any of the embodiments herein, the pump portion is adapted or The pump may have a semi-compliant (collectively referred to as compliant) outer structure. In various embodiments, the compliant portion is flexible. In various embodiments, the compliant portion only partially deforms under pressure. For example, the central portion of the pump may be formed with a compliant outer structure, such that it deforms in response to valve forces. In this manner, the external force of the pump against the valve leaflets is reduced. This can help prevent damage to the valve at the location where the working portion traverses the valve.

[0075]

[0093] One aspect of the present disclosure is an intravascular blood pump having a distal impeller axially spaced from a proximal impeller. In one embodiment, the distal and proximal impellers are separated from each other. For example, the distal and proximal impellers may be connected only by being individually attached to a common drive shaft. This differs from impellers having multiple blade rows. The phrase "distal impeller" as used herein does not necessarily mean the most distal impeller of the pump, but may generally refer to an impeller located distal to the proximal impeller, even if there are additional impellers located distal to the distal impeller. Similarly, the phrase "proximal impeller" as used herein does not necessarily mean the most proximal impeller of the pump, but may generally refer to an impeller located proximal to the proximal impeller, even if there are additional impellers located proximal to the proximal impeller. Axial spacing (or any derivative thereof) refers to spacing across the length of the pump segment, such as along the longitudinal axis of the pump segment, even if curvatures exist within the pump segment. In various embodiments, the proximal and distal impellers are each disposed within a respective housing and configured to maintain a precise and consistent tip clearance, with the span between the impellers having a relatively flexible (or fully flexible) fluid lumen. For example, each impeller may be disposed within a respective housing having an outer wall with a relatively high stiffness to resist radial collapse. The section between the impellers may have a relatively high stiffness, and in some embodiments, this section is maintained open primarily by fluid pressure therein.

[0076]

[0094] In any of the embodiments herein, a tip clearance exists between the outer diameter of the impeller and the inner diameter of the fluid lumen. In some embodiments, the tip clearance may be between 0.01 mm and 1 mm, such as between 0.05 mm and 0.8 mm, or such as between 0.1 mm and 0.5 mm.

[0077]

[0095] FIG. 6 is a side view of an exemplary distal portion 20 of the fluid pumping device 10. The distal direction is indicated with a "D" and the proximal direction is indicated with a "P." The distal portion 20 (and other distal portions herein) may also be referred to as a pump portion. The distal portion 20 has an expandable member 30 having a conduit for fluid flow as described herein. The expandable member 30 has a support structure 33 (which may also be referred to herein as a scaffold), which in this embodiment is a stent-like member but may be constructed using any of the embodiments presented herein. The expandable member 30 further has a membrane 34 having a distal end 31 and a proximal end 32. The membrane 34 is coupled to the support structure 33. The membrane 34 at least partially creates and defines an internal lumen through which fluid flows when the impellers 40 and 50 are actuated. The membrane 34 may have any of the characteristics of any of the conduits described herein. When support structure 33 expands to the deployed, expanded configuration shown in Figure 10, the conduit also assumes the open configuration shown in Figure 10. When impellers 40 and 50 are actuated, fluid flow is generally indicated in the direction of arrow "F." Impellers 40 and 50 may be any of the impellers described herein and may have any of the characteristics described herein.

[0078]

[0096] 7A-7F show an example pump portion 201 of an example blood pump. 201 may be used interchangeably with any other embodiment of any of the blood pumps herein. Figure 7A is a side view and Figure 7B is a side cross-sectional view.

[0079]

[0097] Pump section 201 has a drive cable tubular member 204 to which a distal impeller 203 and a proximal impeller 202 are fixed. Rotation of drive cable tubular member 204 via rotation of a drive cable (not shown) rotates the impellers. More or less than two impellers may be included in the pump section.

[0080]

[0098] The pump portion 201 further has a collapsible housing 205 having a collapsible support structure 206 (which may also be referred to herein as a scaffold) with a proximal end 210 and a distal end 211, and a conduit 212 (see FIG. 17E) that forms a fluid lumen between the distal and proximal ends of the fluid lumen.

[0081]

[0099] Pump portion 201 has an optional intermediate (which may be referred to herein as central, i.e., between the impellers) member 209 located between the two impellers, and intermediate member 209 may be any central member herein.

[0082]

[0100] In any of the embodiments herein, the distal impeller can have a smaller length than the proximal impeller, as shown in the device of Figure 7A.

[0101] FIG. 7C is a side view of the proximal portion of support structure 206 in an expanded configuration (other portions are not shown for clarity). FIG. 7D is a proximal end view of the support structure. The region shown generally surrounds impeller 202 in FIGS. 7A and B. Support structure 206 can be formed using a variety of techniques, such as laser cutting a tubular stock material. Support structure 206 has multiple arms (four in this embodiment) that transition from a larger diameter in the proximal region to a smaller diameter in region 218. Each arm has a curve in region 219 and is vertical between the curve regions as shown. The vertical region can help stabilize the transition region between the larger and smaller diameter regions, reducing, and preferably eliminating, its effect on the fluid at the outlet.

[0083]

[0102] In the larger diameter region of the support structure, the support structure 206 has alternating peaks 221 (only two are labeled). Alternating in this context refers to the axial location of the peak's end. Each of the four arms forms a peak that extends further proximally with the adjacent peak. The alternating peaks can facilitate containment within the jacket upon collapse of the pump portion and can offset the fill volume. As used herein, peaks can be considered as valleys determined by orientation, in the same way that convex and concave are related terms.

[0084]

[0103] The support structure 206 further includes axially spaced helical regions 213 (only some of which are labeled in FIGS. 7A and 7B ) having multiple arms (or portions of arms) with a helical configuration. In FIG. 7C , the helical region 213 includes helical arms 214 (only four of which are labeled). In this embodiment, the helical arms extend between adjacent non-helical regions of the support structure. The regions between the helical regions can have any number of configurations, and exemplary configurations are shown. In this exemplary embodiment, the proximal impeller 202 axially overlaps at least a portion of two adjacent helical regions 213, and the distal impeller axially overlaps at least a portion of two adjacent helical regions 213. Any impeller can axially overlap one or more helical sections 213. The pitch of the helical arms may vary.

[0085]

[0104] FIG. 8 illustrates an expandable member 25, which is one of at least two expandable members (which may also be referred to herein as an expandable housing), such as the expandable members of FIGS. 3A-3D. 8 shows a scaffold design with a number 250, where each expandable member surrounds an impeller. The scaffold design of FIG. 8 has more proximal struts 251 (only one numbered) than the designs of FIGS. 7A-7D (there are nine in this illustrated embodiment instead of four). Having separate expandable members 250 in each impeller allows for the ability to have very different geometries in any of the individual impellers. Additionally, this design reduces the amount of scaffold material (e.g., nitinol) over the length of the scaffold (compared to other full-length scaffolds herein), thereby improving compliance when contained within a jacket. Potential challenges with this design may include creating a continuous membrane between the expandable members in the absence of axially extending scaffold material (see FIG. 3A). Additionally, the relatively large number of proximal struts 251 in the outflow path may disrupt the outflow more than designs with fewer struts, such as the four struts of the embodiment of FIGS. 7A-7D. Any other embodiment of the expandable member herein, such as the expandable member described in Figures 3A-3D, may be incorporated by reference into this exemplary design. Figure 8 shows a top view of the scaffold in an unexpanded configuration to further illustrate this design.

[0086]

[0105] Figure 9 shows a scaffold design with the same general pattern as Figure 8, but this scaffold pattern is not separated into two separate sections; rather, the scaffold is a single elongated member as shown. Figure 9 is in its expanded form. The scaffold design of Figure 9 has a proximal end 256 and a distal end 257 (i.e., hub attachment region) with continuous integral formations, rather than a separate hub proximal end as in the designs of Figures 7A-7D. It may be easier to apply (e.g., cover) a membrane to a single scaffold with this design and the designs of Figures 17A-D (e.g., compared to separate, axially spaced expandable members, such as in Figure 8). An illustrative drawback may be the relatively large number of proximal struts (nine in this embodiment), which, like the design of Figure 8B, may disrupt the outflow area as blood exits the fluid lumen. This particular pattern may also be excessively stiff for some applications, i.e., for access routes where greater curvature and bending are desired. This design has a relatively high stiffness over its axial length and cannot bend or bend easily, with peaks 258 and valleys 260 in adjacent sections 261 aligned radially and joined by connectors 259 that are parallel to the longitudinal axis of the fluid lumen.

[0087]

[0106] Figure 21B shows an example scaffold design. A central region "CR" exists between the regions where the proximal and distal impellers are located. The benefits of increased flexibility in this region are described herein.

[0088]

[0107] The scaffold can have a relatively stiff impeller region (IR) adjacent the central region where the impeller is located (not shown). The relatively high stiffness in the impeller region IR can help maintain tip clearance and impeller concentricity. This scaffold pattern thus provides a flexibility distribution along its length with a relatively less flexible proximal section ("IR"), a relatively more flexible central region "CR", and a relatively less flexible distal section "IR". The relatively less flexible sections (i.e., the two IR regions) are where the proximal and distal impellers can be located (not shown, but other embodiments are fully incorporated herein in this regard), with a relatively more flexible region in between. The benefits of the relative flexibility of these individual sections are discussed elsewhere herein.

[0089]

[0108] Part of a blood pump system (such as any blood pump system herein) One or more impellers may be rotated at a relatively high speed, such as between 10,000 RPM and 50,000 RPM. The impeller may be rotated by being rotatably coupled to a drive member (e.g., a drive cable) or by another component rotatably coupled to the impeller, which may be rotated by an energy source (e.g., a motor). Rotating the drive member at the same RPM as the impeller may cause wear on the drive member, may cause vibration, and likely require lubrication of the drive member (embodiments of exemplary lubrication systems are described elsewhere herein). It may be advantageous to rotate the drive member at a lower speed than the impeller while rotating the impeller at a desired high RPM. One embodiment of the present disclosure is a blood pump having one or more drive members that may be rotated at a lower RPM than the one or more impellers. This may reduce wear on the drive members, reduce the need for lubrication, and reduce vibration. This may be particularly advantageous in applications where the blood pump is used for relatively long periods of time (e.g., 24 hours or more). For example, this may be particularly significant in the case of signs of cardiogenic shock.

[0090]

[0109] The following disclosure provides exemplary method steps that may be performed when using any of the blood pumps described herein, or portions thereof. It should be understood that not all steps need be performed, and these steps are intended to be exemplary procedures. Furthermore, it is contemplated that the order of one or more steps may be varied as appropriate in some instances.

[0091]

[0110] Prior to use, the blood pump may be prepared for use by priming the lumen (including any tubular spaces) or pump assembly with a 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 the console. Alternatively, the catheter may be connected to the console and / or a separate pump that is used to prime the catheter to remove air bubbles.

[0092]

[0111] After priming the catheter, access to the patient's vasculature can be achieved using an appropriately sized introducer sheath (for example, but not limited to, via femoral access). Then, using standard valve crossing techniques, the diagnostic pigtail catheter can be advanced over, for example, a 0.9 mm (0.035") guidewire until the pigtail catheter is firmly positioned at the target site (e.g., the left ventricle). The guidewire can then be removed, and a second wire 320 (e.g., a 0.457 mm (0.018") wire) can be inserted through the pigtail catheter. The pigtail catheter can then be removed (see FIG. 11A), and the blood pump 321 (including the catheter, catheter sheath, and pump portion within the sheath; see FIG. 11B) can be advanced over a second wire toward the target location (e.g., the left ventricle "LV"), such as across the aortic valve "AV," using, for example, one or more radiopaque markers to position the blood pump.

[0093]

[0112] Once proper placement is confirmed, the catheter sheath 322 (see FIG. 11C) can be retracted, first exposing the distal region of the pump portion. In FIG. 11C, the distal region of the expandable housing has been released from the sheath 322 and allowed to expand, as has the distal impeller 324. The proximal end of the housing 323 and the proximal impeller 325 have not yet been released from the sheath 322. Continuing to retract the sheath 322 past the proximal end of the housing 323 allows the housing 323 and the proximal impeller 325 to expand (see FIG. 11D). The inflow region (indicated with an arrow even though the impeller is not yet rotating) and the distal impeller are within the left ventricle. The outflow region (indicated with an arrow even though the impeller is not yet rotating) are within the left ventricle. The pump section includes a pumping section having a distal end (indicated with an arrow) and a proximal impeller in the ascending aorta (AA). A region of the outer housing between the two impellers, which may be more flexible than the housing region surrounding the impellers, extends to straddle the aortic valve AV, as described in more detail herein. In the exemplary operating position shown, the inlet portion of the pump section is distal to the aortic valve in the left ventricle and the outlet of the pump section is proximal to the aortic valve in the ascending aorta ("AA").

[0094]

[0113] A second wire (e.g., a 0.018" guidewire) may then be moved prior to operation of the pump assembly (see FIG. 11E). If desired or necessary, the pump portion may be reoriented (actively or passively) at one or more locations described herein, as shown in FIG. 11F. For example, the area between the two impellers may be reoriented by applying tension to a tensioning member that extends to a location between the two impellers. This reorientation may be desired or necessary to accommodate particular anatomical structures. If necessary, the pump portion may be repositioned to achieve the intended placement, such as, for example, placing the first impeller on one side of the heart valve and the second impeller on the other side of the heart valve. It should be understood that in FIG. 11F, the pump portion does not interfere with or interact with the mitral valve in any way, even though it may appear to do so from the illustration.

[0095]

[0114] In some examples herein, the pump has one or more radial support scaffolds adapted to radially support a blood conduit or shroud. These radial support scaffolds may be referred to herein as scaffolds, expandable members, support structures, etc., and generally radially support an expandable and collapsible fluid conduit or shroud herein. In some examples, the one or more radial support scaffolds cause the fluid conduit to assume an expanded configuration upon release from the sheath.

[0096]

[0115] Some conduit support members herein are described as being self-expanding materials such as nitinol. However, in some alternative embodiments, the scaffold may be polymeric rather than metal or a metal alloy such as nitinol. Metal alloys may be referred to herein as metals, and both may be generally referred to herein as metallic. In some embodiments, the expandable housing or shroud may be entirely or substantially entirely free of metallic materials such as nitinol. Substantially free in this context may mean that more than 90% of the shroud is free of metallic materials. Radial support may be provided by regions of polymeric material rather than metallic material. The expandable shroud or housing may include one or more membrane materials and one or more generally high-stiffness polymer scaffolds that radially support the blood conduit at the location of the polymer scaffold. In general, any of the radial support scaffolds described herein (e.g., expandable members) may be polymeric scaffolds.

[0097]

[0116] In some embodiments, the relatively high stiffness of the one or more polymeric support members can be achieved by utilizing a relatively higher durometer material for the scaffold compared to the shroud membrane material. In some embodiments, the relatively high stiffness of the one or more polymeric scaffolds can include a relatively thicker region of polymeric material. In some embodiments, the polymeric scaffold can be thicker than the membrane and have a higher durometer than the membrane.

[0098]

[0117] Polymeric scaffolds can offer exemplary benefits compared to metallic scaffolds. For example, shroud fabrication can be simplified when utilizing polymeric materials, examples of which are presented herein. In addition, polymeric scaffolds can provide higher A shroud construct having strength can be provided, where the likelihood of membrane delamination can be reduced.

[0099]

[0118] For example, the expandable members 343 and 344 in the illustrative blood pump of FIG. 3A can be polymer scaffolds that can be secured to a polymer membrane conduit 356. This is one example of an expandable and collapsible shroud comprising first and second axially spaced polymer scaffolds, where the first and second polymer scaffolds can be unconnected and secured to one another by being commonly bonded to the membrane conduit 356. The pump can be used in the position shown in FIG. 4, for example. Additionally, by way of example only, the scaffold shown in FIG. 8 can be a polymer scaffold. Struts 251 shown in FIG. 8 (and even distal struts not labeled) can be polymeric or metallic. If polymeric, struts 251 can be integrally formed with the cylindrical region of the polymer scaffold. The term scaffold as used herein generally refers to radial support for the shroud, and struts are generally considered to extend away from the shroud, even if integrally formed with the scaffold. Additionally, merely by way of example, the scaffolds shown in Figures 9 and 10 may be polymeric scaffolds. The struts extending from the generally cylindrical scaffold may be polymeric or may be metallic. This is described in more detail herein. Figure 10 is an example of a polymeric scaffold extending along the entire length or substantially the entire length of the expandable shroud 290.

[0100]

[0119] FIG. 10 shows exemplary regions of an expandable and collapsible shroud 290. In some embodiments, a pump can have first and second impellers, where "IR" refers to the impeller region of the expandable shroud. "CR" refers to the central region, located between the two impeller regions. A polymer scaffold herein can extend along all or a portion of the shroud. A polymer scaffold can extend along the entire length of the shroud or substantially the entire length of the shroud (e.g., FIG. 10). A polymer scaffold can be disposed at the impeller region (e.g., FIG. 3A). A first polymer scaffold can be disposed in the first impeller region and a second polymer scaffold can be disposed in the second impeller region.

[0101]

[0120] In FIG. 10 , different regions of the scaffold can be made of different materials. By way of example only, the scaffold in the impeller region IR can be made of nitinol, while the scaffold in the central region can be a polymeric material. This can be advantageous, for example, when it is desirable for the central region to have greater flexibility than the impeller region, but a metallic material with higher stiffness is desired in one or both of the impeller regions. This can be advantageous when the central region can benefit from being atraumatic, such as when placing the central region against sensitive tissue such as an aortic heart valve. Strands or elongated elements of different materials can be connected at the junction of the impeller region and the central region, thereby forming a continuous strand even if they are not integrally formed from the same type of material. This is one example of a polymeric scaffold extending along at least the central region of the expandable shroud.

[0102]

[0121] Some blood pumps can have a single impeller that can be located in the proximal or distal half of the expandable shroud. These pumps can include any of the polymer scaffolds described herein. For example, in a blood pump having an impeller in the distal region of the shroud, the impeller region can have a metal scaffold, but the polymer scaffold can extend proximally from the impeller region. For example, in a blood pump having an impeller in the proximal region of the shroud, the impeller region can have a metal scaffold, but the polymer scaffold can extend proximally from the impeller region. It can extend distally from the wheel region.

[0103]

[0122] The polymer scaffold can have any location and length desired to impart physical properties to any portion of the shroud.

[0123] Within any of the individual polymer scaffolds herein, the stiffness of the polymer scaffold may vary over its length. This may be advantageous when it is desirable to vary the properties of the shroud at different axial locations. Additionally, the stiffness may vary gradually, since abrupt changes in stiffness along the length of the shroud may generally be less desirable. For example, a gradual transition in durometer may help prevent more abrupt transitions. Durometer transitions may be formed using a masking technique. For example, a first polymeric material may be sprayed at a desired location and adjacent areas masked. Then, a second polymeric material having a different durometer may be sprayed, masking the previously sprayed area having the first durometer. This is merely one example and description of creating a polymeric scaffold with varying durometers along its length, including gradual changes in durometer.

[0104]

[0124] Additionally, when there are two axially spaced apart polymer scaffolds, such as in Figure 3A, the polymer scaffolds at the ends of the shroud can have different stiffnesses, such as having different durometers. Additionally, each of the axially spaced apart polymer scaffolds can have a durometer that varies along its length, and the manner in which the axially spaced apart polymer scaffolds vary along their length can be varied. For example, one of the polymer scaffolds can have a greater variation in durometer than the other.

[0105]

[0125] In some embodiments, the polymer scaffold extends the entire length of the shroud or substantially the entire length of the shroud, such as in Figures 9 and 10 where the scaffold is polymeric. The scaffold can have higher stiffness in the impeller region than in the central region, which can provide greater radial support in the impeller region and can also provide greater flexibility in the central region. The higher stiffness in the impeller region can be provided, for example, by a higher durometer material and / or by a greater thickness.

[0106]

[0126] Any of the membranes herein can have a non-constant stiffness along its length. For example, the membrane can have a higher stiffness in the impeller region, thereby providing greater radial support in the impeller region than in the central region. In some embodiments, both the membrane and the scaffold can have a higher stiffness (e.g., higher durometer) (on average) in the impeller region than in the central region.

[0107]

[0127] As used herein, the phrase impeller region refers to at least a portion of the shroud that surrounds the impeller, not necessarily the entire length of the impeller. For example, the impeller region can surround a significant portion of the impeller, but need not surround the entire impeller.

[0108]

[0128] Some polymer scaffolds herein can include fibrous or woven polymer elements that can be filled or saturated with polymer to form a laminate. In these embodiments, the polymer scaffold can be annular or cylindrical bands rather than elongated elements that are further spaced apart as described herein. For example, the polymer scaffold can extend around an expandable shroud. The shroud may include fiber elements or woven polymer elements extending along any length of the shroud. The fibers may be located in the impeller region, the central region, and / or extend along substantially the entire length of the shroud.

[0109]

[0129] The polymeric scaffolds herein can have a durometer greater than the durometer of the membrane of the fluid conduit. The polymeric scaffolds herein can have a stiffness greater than the stiffness of the membrane. This greater stiffness can be due, at least in part, to the durometer of the material. In any embodiment having at least one polymeric scaffold, any other suitable structure (e.g., one or more impellers) or methods of use herein are incorporated by reference into these embodiments.

[0110]

[0130] 12A and 12B illustrate an exemplary expandable housing or shroud. For example, for clarity, the proximal and distal struts of the housing are not shown. The shroud or housing 330 has a conduit defining a fluid lumen having a fluid lumen distal end 333 (adjacent an inflow portion 336) and a fluid lumen proximal end 334 (adjacent an outflow portion 335). The shroud 330 has an elongated body member 331 (e.g., a membrane) and a polymer scaffold, in this example, having multiple polymeric elongated elements 332A and 332B. In this merely exemplary embodiment, the blood pump has a distal impeller 337 and a proximal impeller 339, examples of which are presented herein. Although not described, other structures, such as a drive mechanism having a drive cable and a coupling member 338, may be incorporated into this embodiment. In other embodiments, the pump section may have fewer or more than two impellers. The pump may, for example, have a single impeller in the distal half of the conduit, or may have a single impeller in the proximal half of the conduit.

[0111]

[0131] 12B shows a partial cross-sectional side view of the pump of FIG. 12A (showing only one impeller). In this exemplary embodiment, at least a portion of relatively high durometer elongated elements 332A and 332B are encapsulated within membrane 331, which has a low durometer, as shown. While two distinct elongated elements are shown as support structures 332A and 332B, it should be understood that any of the multiple elongated elements (which are helices in this exemplary embodiment) can be considered a separate elongated element, and all of the separate elongated elements collectively can be considered a polymeric scaffold. The elongated elements can have any other configuration, such as any of the configurations shown herein (e.g., any non-helical configuration).

[0112]

[0132] FIG. 12A shows an exemplary embodiment in which the pump has a shroud with a polymer scaffold comprising polymeric radial elongate elements 332A and 332B that together form a polymeric radial scaffold.

[0113]

[0133] FIGS. 13A and 13B show an embodiment of a foldable and expandable pump shroud similar to that shown in FIGS. 12A and 12B. Shroud 330′ may be the same as the shroud of FIGS. 29A-B in all respects not specifically mentioned herein. All reference numerals in FIGS. 13A-B are numbered the same but with a prime symbol (′) to indicate that the structural parts may be the same in all other respects. In FIGS. 13A and 13B, one or more elongated elements 332A / B′ are embedded within body member 331′ rather than being enclosed within the body member as in FIGS. 12A and 12B. Elongated elements 332A′ / B′ are embedded within the outer surface of body member (e.g., membrane) 331′, but may alternatively be embedded within the inner surface of body member 331′. Alternatively, one or more elongate elements may transition from the outer surface of body member 331' to the inner surface of body member 331'.

[0114]

[0134] In alternative embodiments, any of the elongate elements herein may be any combination of encapsulated or embedded within an elongate body member, for example, an elongate element may be embedded within the outer surface of the membrane in some locations, encapsulated within the membrane in some other locations, and embedded within the inner surface of the membrane in some locations.

[0115]

[0135] At least a portion of the polymer scaffold has a higher durometer than at least a portion of the membrane. The higher durometer of the scaffold can help support the shroud, while the membrane, having a lower durometer, generally helps provide the overall desired flexibility of the shroud. In some embodiments, the scaffold can have a durometer that is 5D to 100D greater (on average) than the durometer of the membrane, such as 10 to 100 units (on average) greater on the Shore hardness scale, or 20 to 100 units (on average) greater on the Shore hardness scale.

[0116]

[0136] While membranes 331 and 331′ can be made from a single type of material, any of the membranes herein can be made from two or more types of material. As used in this context, “type” of material does not require (but may be or include) different chemical compositions, but can include the same material with different durometer values ​​(e.g., one portion made of PEBAX 500 and one portion made of PEBAX 75D). Different materials can extend over or along various different portions of the housing. For example, a membrane of one type of material can extend less than half the length of the housing, half the length of the housing, or more than half the length of the housing. Additionally, a second type of material can extend less than half the length of the shroud, half the length of the shroud, or more than half the length of the shroud. Additionally, the membrane can have higher stiffness in one or more regions within which one or more impellers are disposed, such as by being made of a material having a higher durometer than axially adjacent regions (i.e., regions that do not radially surround the impeller). Increasing the stiffness of these regions can have various benefits, such as increasing the stiffness of the axial region within which the impeller is located, thereby helping to maintain tip clearance between the blades and the shroud. Additionally, a central region of the shroud can be made to have a lower stiffness than one or more axially adjacent impeller regions by having an elongated body member that uses a material in the central region that has a lower stiffness (e.g., a lower durometer) than axially adjacent sections. For example, the membrane can be made to have a lower stiffness (e.g., a lower durometer and / or a smaller thickness) along the length Lc in FIG. 5, which illustrates the axial spacing between the impellers in this exemplary embodiment. In some embodiments with a single impeller, the region with lower stiffness can extend a greater distance than along the length Lc alone.For example, a central region having a lower stiffness can provide greater flexibility in the central region where the shroud may be positioned near delicate tissue, such as delicate valve tissue. In other words, one or more regions of the shroud adjacent to the central region can be adapted to have a higher stiffness than the central region, optionally comprising a membrane having a higher durometer and / or greater thickness.

[0117]

[0137] Additionally, throughout the housing, one or more individual sections of the scaffold may be made from different types of materials. For example, one or more separate scaffolds may be made from a higher durometer than one or more other support member sections. That is, one or more scaffolds may be made from a different durometer than one or more other support member sections. They may be made from different types of materials. By way of example only, a first scaffold may be made from a first type of material, while an adjacent scaffold may be made from a different type of material. This may be a repeating pattern over, along, or around the shroud. Additionally or alternatively, one or more polymeric scaffolds may have a higher stiffness (e.g., corresponding to a higher durometer) at the impeller location, or at all impeller locations in designs with more than one impeller. For example, one or more support members may have a higher durometer in regions along Lsp and / or Lsd (shown in exemplary FIG. 5).

[0118]

[0138] In any of the embodiments herein comprising one or more polymer scaffolds, one or more metallic (e.g., nitinol) support structures may further be included in one or more regions of the shroud with or without the polymer scaffold. Alternatively, a metallic scaffold may be disposed around the shroud region where the impeller is located, optionally where separate metallic scaffolds are disposed along two or more separate regions where each of two or more impellers is located.

[0119]

[0139] Expandable and collapsible shrouds comprising polymer scaffolds can be manufactured using a variety of techniques. By way of example only, the polymer scaffold can be cast or molded with a dissolvable core or cavity. If the struts are also polymeric, they can be cast or molded together with the polymer scaffold. By way of another example only, the polymer scaffold can be made by laser cutting structures (e.g., cylindrical structures) to remove material and leave the scaffold structure.

[0120]

[0140] Additionally, as discussed above, polymeric scaffolds having varying durometer values ​​along their length can be fabricated using a variety of techniques, such as multi-shot molding, solvent or spray casting, and / or masking techniques.

[0121]

[0141] Bonding the polymer scaffold to the membrane can be performed using a variety of techniques, including but not limited to: a polymer material can be sprayed onto the formed polymer scaffold, the formed scaffold can be dipped and coated in a membrane material, the formed polymer scaffold can be solvent bonded or adhesively adhered to the membrane material, or a combination of the above to form a polymer scaffold with an attached polymer membrane.

[0122]

[0142] Any of the expandable shrouds herein can have a polymer scaffold that includes a material that is different from the material of the polymer membrane. Any of the expandable shrouds can be the same material as the polymer membrane, but the scaffold and membrane have different durometers.

[0123]

[0143] Blood pumps herein can have proximal and distal struts extending proximally and distally from an expandable shroud, where the proximal strut facilitates folding of the shroud. FIG. 8 shows strut 251 as an example. In some embodiments where the pump includes one or more polymer scaffolds, the pump struts (e.g., strut 251) can be polymeric or metallic. For example, if scaffold 250 shown in FIG. 8 is a polymeric scaffold, strut 251 extending axially therefrom can also be polymeric. In other embodiments where the scaffold is polymeric, the struts can be metallic, such as nitinol.

[0124]

[0144] In some embodiments, the struts are metal, such as Nitinol, whereas the wings The impeller region has a polymer scaffold. Metal struts can extend some distance into the impeller region of the shroud and can be bonded to the shroud membrane and / or polymer scaffold. FIG. 14 shows a portion of an example collapsible and expandable shroud 401 of a pump 400, with other aspects of the pump, such as the drive mechanism and impeller, not shown here for clarity. The shroud 401 has a membrane 403 and a polymer scaffold in the impeller region. The membrane 403 has an end 404, which can be a proximal or distal end. The polymer scaffold has an elongated element 402, only two sections of which are labeled. The polymer scaffold can be any of the scaffolds described herein. Pump 400 has metal struts 405 having regions or sections 405' that extend into the shroud and are bonded to membrane 403 to bond struts 405 to shroud 401. This is an example of a metal strut bonded to a shroud with a polymer scaffold in the impeller region. While strut region 405' is shown as engaging the polymer scaffold at location 406, there may be some spacing between the strut and the polymer scaffold. One or both ends of the pump shroud may be configured in the manner shown and described in connection with FIG. 14 (e.g., one or both of the inlet and outlet). It should be understood that any other aspect of the pump (e.g., impeller) herein may be incorporated into the portion of the pump of FIG. 14.

[0125]

[0145] As described in more detail herein, in some embodiments, struts 405 may be polymeric and may be integrally formed with a polymer scaffold. One or both ends of the shroud may be configured in this manner. In some embodiments, the first and second impeller regions may have a polymer scaffold integrally formed with polymer struts extending axially from the respective impeller regions.

[0126]

[0146] Some catheter pumps herein can have first and second expandable and collapsible scaffold sections that are axially spaced apart. The first and second expandable and collapsible scaffold sections can have different maximum or maximum dimensions, with the smaller sized sections having a more gradual change in radial dimension to facilitate their containment within the outer sheath. Any other suitable structure or method described herein can be incorporated into these exemplary embodiments.

[0127]

[0147] For example, Figure 15 shows a partial view of an exemplary embodiment of a catheter blood pump having a pump portion 370. The pump portion 370 has an expandable and collapsible shroud 371 defining a blood lumen therein. The catheter pump further has an expandable and collapsible scaffold, the scaffold comprising a first scaffold section or portion 372 having an expanded configuration and a second scaffold portion 373 having an expanded configuration, the second portion 373 being axially spaced from the first portion. The second portion 373 has a maximum outer dimension smaller than the maximum outer dimension of the first portion 372, as shown. In this embodiment, the shroud 371 carries the scaffold first portion 372. One or more impellers, not shown for clarity, may be disposed within the shroud 371, although any of the impellers described herein may be included in the example of Figure 15. An outlet is indicated as a flow in Figure 15. First and second scaffold portions 373 and 372 may be joined by one or more collapsible outflow struts 373 extending between the first portion 372 and the second portion 373. The catheter pump has a pump outflow between the first and second portions, which is shown as flow in FIG.

[0128]

[0148] When the shroud 371 is in the expanded configuration as shown in FIG. 73 has a maximum or outermost radial dimension (e.g., diameter) that is smaller than the maximum radial dimension (e.g., diameter) of first portion 372. Maximum in this context refers to the maximum radial dimension (perpendicular to the longitudinal axis) measured at a particular section, even if the radial dimension of this particular section is not constant along its entire length. For example, the referenced tapered transition section 377 may be considered part of second portion 373, despite its reduced radial size relative to the larger cylindrical region of the second portion.

[0129]

[0149] The reduced-dimension expandable portion (e.g., second portion 373) can have a shape set configuration (which may also be referred to herein as a "geometry") adapted to achieve a more gradual reduction in the dimension between the shroud 371 and the diameter of the shaft 376.

[0130]

[0150] The outer profile of the expandable portion of the catheter pump shown in FIG. 15 has two steps, where the radial dimension changes along its length. For example, the expandable portion has a transition portion, which is an outflow, between first portion 372 and second portion 373. The catheter pump also has a transition region 377. These "steps" increase the dimension in multiple places at the transition from catheter shaft 376 to expandable shroud 371. Both "steps" can have one or more expandable elements (e.g., struts). Furthermore, this stepped outer profile configuration can facilitate stowing the pump portion within an outer sheath by potentially providing a more gradual change in outer radial dimension compared to a more abrupt change in a single location.

[0131]

[0151] The impeller may have a portion that extends partially outside the shroud 371 or may be located entirely within the shroud 371 .

[0152] 15 further illustrates an exemplary blood flow inhibiter 382, ​​which may also be referred to herein as a seal. In this embodiment, the blood flow inhibiter may extend across the path of blood flow and may function to prevent blood from pooling or flowing within second section 373. In this embodiment, the blood flow inhibiter is affixed to a shaft (optionally cylindrical) that extends through second section 373, optionally creating a seal between the blood flow inhibiter and the shaft. In some embodiments, the blood flow inhibiter may comprise a membrane or septum or other similar relatively thin, deformable material that may function to reduce or prevent blood flow.

[0132]

[0153] By way of example only, in some embodiments, the first scaffold section (e.g., 372) can have a diameter of 4.5 mm to 8.5 mm (e.g., 5.5 mm to 7.5 mm) and the second scaffold section (e.g., 373) can have a diameter of 3 mm to 6.5 mm (e.g., 4 mm to 5.5 mm).

[0133]

[0154] 15, multiple struts extend between first portion 372 and second portion 373, where the struts are spaced apart to allow blood to flow between them at the outflow portion. Strut 375 is shown extending radially outward and axially from second portion 373 to first portion 372.

[0134]

[0155] Similar to the manner in which the shroud membrane is connected to the shroud scaffold section herein, the catheter pump shown in FIG. 15 further has a membrane 378 attached to the second scaffold portion 373. The membrane 378 passes completely through the transition section 377 to prevent blood from pooling or entering within the second section 373. The second section 373 may extend to accommodate the impeller 382. A seal or flow restrictor 382 may be an extension of the membrane, such that the membrane (which may comprise one or more membrane materials) covers the entire second section 373 and prevents blood from entering therein. A shaft may pass through the flow restrictor 382, ​​where a drive mechanism extends through the shaft and causes rotation of one or more impellers. Depending on the supply means of the pump portion, the seal 382 may be at the distal end of the second section 373.

[0135]

[0156] The catheter pump of Figure 15 further includes a tapered region 377 between the second portion 373 and the catheter shaft 376, where the tapered region is configured to facilitate folding of the second portion 373. In some embodiments, the tapered region 377 can include the second portion of the scaffold. In this example shown in Figure 15, the transition region 377 includes a membrane 378.

[0136]

[0157] At least one of the first and second scaffold portions 372 and 373 can be polymeric, such as any of the polymeric scaffolds herein.

[0137]

[0158] The first scaffold portion 372 and the second scaffold portion 373 may be integrally formed from the same source material, such as nitinol or a polymeric material. Additionally, the outflow struts 375 may be integrally formed with the first scaffold portion 372 and the second scaffold portion 373.

[0138]

[0159] The catheter pump of FIG. 15 is an example of a catheter pump having a first plurality of tapered struts (within region 377) extending radially outward in a first axial direction (e.g., distally) and a second plurality of tapered struts 375 extending radially outward in a first axial direction (e.g., distally), where the first plurality of struts are axially spaced apart from the second plurality of struts. The present invention includes the following aspects. 1. A catheter blood pump comprising: an expandable and collapsible shroud defining a blood lumen, the shroud comprising a polymeric scaffold along at least a portion of a length of the shroud; one or more impellers disposed at least partially within the shroud; A catheter blood pump comprising: 2. A catheter blood pump as described in 1 above, wherein the expandable and foldable shroud has higher rigidity in the distal impeller region and the proximal impeller region than in a central shroud region between the distal impeller region and the proximal impeller region. 3. A catheter blood pump as described in claim 1, wherein the polymer scaffold extends along the entire length or substantially the entire length of the shroud. 4. A catheter blood pump as described in claim 1, wherein the polymer scaffold does not extend along the entire length of the shroud, but rather extends around at least a portion of one of the one or more impellers. 5. A catheter blood pump as described in 3. above, wherein the polymer scaffold is a first polymer scaffold, the shroud comprises a second polymer scaffold not connected to the polymer scaffold, and the second polymer scaffold is axially spaced from the first polymer scaffold. 6. The catheter blood pump described in claim 4, wherein the second polymer scaffold extends around at least a portion of a second impeller of the one or more impellers. 7. A catheter blood pump as described in 1 above, wherein the stiffness of the polymer scaffold is not constant along the length of the polymer scaffold. 8. The catheter blood pump described in claim 6, wherein the polymer scaffold has a higher stiffness in a first region around one of the one or more impellers than in a second region that does not extend around the one of the one or more impellers. 9. A catheter blood pump as described in paragraph 7 above, wherein the polymer scaffold has a higher stiffness in a third region around a second impeller of the one or more impellers than in the second region. 10. The catheter blood pump according to claim 8, wherein the second region is a central shroud region between a first impeller and a second impeller of the one or more impellers. 11. A catheter blood pump as described in claim 1, wherein the polymer scaffold extends along a central shroud region between the first impeller region and the second impeller region of the catheter blood pump. 12. A catheter blood pump as described in claim 10, wherein the polymer scaffold extends at least partially into the first and second impeller regions. 13. A catheter blood pump as described in claim 10, wherein the polymer scaffold does not extend along the entire length of the first impeller region and does not extend along the entire length of the second impeller region. 14. The catheter blood pump described in claim 10, wherein the shroud comprises a metal scaffold within the first impeller region and a second metal scaffold within the second impeller region. 15. A catheter blood pump as described in claim 13, wherein the metal scaffold and the second metal scaffold are axially spaced apart but connected and are part of the same scaffold. 16. A catheter blood pump as described in claim 1, wherein the shroud has no or substantially no metal support member. 17. A catheter blood pump as described in claim 15, wherein the shroud is substantially free of metal support members, the proximal end of the shroud comprises axial extensions of proximal metal struts, and the proximal struts are collapsible and positioned and configured to facilitate folding of the shroud. 18. A catheter blood pump as described in claim 15, wherein the shroud is substantially free of a metal support member, the distal end of the shroud comprises an axial extension of a distal metal strut, and the distal strut extends distally from the distal end of the shroud. 19. A catheter blood pump as described in claim 1, wherein the shroud comprises a polymer membrane that at least partially defines a blood lumen, and the polymer scaffold has a stiffness greater than the stiffness of the polymer membrane. 20. A catheter blood pump according to claim 18, wherein the durometer value of the polymer scaffold is higher than the durometer value of the polymer membrane. 21. A catheter blood pump as described in claim 1, wherein the polymer scaffold has variable stiffness along at least a portion of the length of the polymer scaffold. 22. The catheter blood pump described in claim 20, wherein the polymer scaffold has a region where the durometer value of the polymer scaffold changes from a first durometer to a second durometer. 23. A catheter blood pump as described in claim 1, wherein the shroud further comprises one or more metal support members, and the polymer scaffold covers a larger area than the one or more metal supports between the distal end of the shroud and the proximal end of the shroud. 24. A catheter blood pump as described in 1 above, wherein the durometer value of the polymer scaffold is at least 10 units greater on the Shore hardness scale than the durometer value of the shroud membrane. 25. A catheter blood pump as described in paragraph 23 above, wherein the durometer value of the polymer scaffold is at least 20 units greater on the Shore hardness scale than the durometer value of the shroud membrane. 26. A catheter blood pump as described in paragraph 24 above, wherein the durometer value of the polymer scaffold is at least 30 units greater on the Shore hardness scale than the durometer value of the shroud membrane. 27. A catheter blood pump as described in claim 1, wherein the polymer scaffold comprises a plurality of elongated elements spaced apart from one another, the plurality of elongated elements extending around or along at least a portion of the shroud, or both. 28. A catheter blood pump as described in claim 25, wherein the polymer scaffold extends around the entire circumference of the shroud. 29. A catheter blood pump as described in paragraph 25 above, wherein the first and second elongated elements are either in contact with each other so as to be integral, or are separate elements connected within their upper / lower surfaces. 30. A catheter blood pump as described in claim 1, wherein the central region of the shroud comprises a polymer scaffold and has greater flexibility than proximal and distal shroud impeller regions axially spaced from the central region. 31. A catheter blood pump as described in claim 1, wherein the central region of the shroud has a higher flexibility than the proximal and distal shroud impeller regions spaced axially from the central region. 32. A catheter blood pump comprising: an expandable and collapsible shroud defining a blood lumen; an expandable and collapsible scaffold, the scaffold comprising a first portion having an expanded configuration and a second portion having an expanded configuration, the second portion axially spaced from the first portion, the second portion having a maximum outer dimension smaller than a maximum outer dimension of the first portion, and a shroud comprising the first portion; a pump outlet between the first portion and the second portion; one or more impellers disposed at least partially within the shroud; A catheter blood pump having a 33. A catheter blood pump as described in claim 32, wherein the pump outflow section comprises a plurality of struts extending between the first and second sections, the struts being spaced apart to allow blood to flow therebetween. 34. A catheter blood pump as described in claim 33, wherein each of the plurality of struts extends radially outward and distally from the first portion to the second portion. 35. The catheter blood pump described in claim 32, further comprising a membrane connected to the second portion. 36. The catheter blood pump of claim 35, further comprising a seal positioned and dimensioned relative to the second portion to prevent blood flow within the second portion. 37. A catheter blood pump as described in claim 36, wherein the seal is an extension of the membrane connected to the second portion. 38. The catheter blood pump of claim 37, wherein a seal is secured to a cylindrical member extending through the second portion so as to seal the second portion. 39. A catheter blood pump as described in claim 36, wherein a seal is disposed at the distal end of the second portion. 40. The catheter blood pump described in claim 32, further comprising a tapered region between the second portion and the catheter shaft extending proximally away from the second portion, the tapered region configured to facilitate folding of the second portion. 41. The catheter pump described in claim 40, wherein the tapered region comprises a second portion of the scaffold. 42. A catheter blood pump as described in claim 41, wherein the transition region comprises a membrane connected to the scaffold. 43. A catheter blood pump as described in claim 32, wherein at least one of the first and second portions of the scaffold is made of a polymer. 44. A catheter blood pump as described in claim 32, wherein the first and second portions are integrally formed from the same material. 45. A catheter blood pump as described in claim 44, wherein the first and second portions are formed from the same original tubular member. 46. ​​A catheter blood pump as described in claim 45, wherein the outflow struts extending between the first and second portions are integrally formed with the first and second portions. 47. The catheter blood pump described in claim 32, further comprising a first plurality of tapered struts extending axially and radially outwardly and a second plurality of tapered struts extending axially and radially outwardly, the first plurality of struts being axially spaced apart from the second plurality of struts. 48. A catheter blood pump as described in claim 32, wherein the first portion is generally cylindrical and the second portion is generally cylindrical.

Claims

1. 1. A blood pump comprising: an expandable and collapsible scaffold extending from an inlet to an outlet to define a blood lumen, the expandable and collapsible scaffold comprising: a proximal impeller region; a central region disposed distally of the proximal impeller region; and a distal region disposed distally of the central region, the central region being between the distal region and the proximal impeller region, the proximal impeller region and the distal region having a greater stiffness than the central region, the proximal impeller region having a greater thickness than the central region, the central region of the expandable and collapsible scaffold including a plurality of helical arms to define at least one helical region extending between adjacent non-helical regions; a proximal impeller disposed at least partially within the proximal impeller region of the scaffold; A blood pump comprising:

2. The blood pump of claim 1 , wherein at least one of the adjacent non-helical regions axially overlaps the proximal impeller.

3. The blood pump of claim 2 , wherein at least one helical region axially overlaps the proximal impeller.

4. The blood pump of claim 2 , wherein a plurality of helical regions axially overlap the proximal impeller.

5. The blood pump of claim 1 , wherein the proximal impeller region of the expandable and collapsible scaffold includes a plurality of helical arms to define at least one helical region.

6. The blood pump of claim 5 , wherein at least one helical region axially overlaps the proximal impeller.

7. The blood pump of claim 5 , wherein a plurality of helical regions axially overlap the proximal impeller.

8. The blood pump of claim 5 , wherein at least one of the plurality of spiral arms extends between adjacent non-spiral regions.

9. The blood pump of claim 2 , wherein the proximal impeller region comprises at least one helical region and the central region comprises at least one non-helical region.

10. The blood pump of claim 1 , further comprising a membrane coupled to the expandable and collapsible scaffold to define a fluid conduit impermeable to blood.

11. The blood pump of claim 1 , wherein the expandable and collapsible scaffold comprises nitinol.

12. The blood pump of claim 1 , wherein the expandable and collapsible scaffold comprises a polymeric structure.

13. 13. The blood pump of claim 12, wherein the first durometer value of the proximal impeller region is higher than the second durometer value of the central region.

14. 2. The blood pump of claim 1, wherein the expandable and collapsible scaffold comprises a distal impeller region disposed distally of the central region, the distal impeller region having a stiffness greater than the stiffness of the central region, and the blood pump further comprises a distal impeller disposed at least partially within the distal impeller region of the scaffold.

15. 15. The blood pump of claim 14, wherein the stiffness of the proximal impeller region is substantially similar to the stiffness of the distal impeller region.

16. 10. The blood pump of claim 1, wherein the proximal impeller region is configured to maintain a tip clearance between the proximal impeller and the expandable and collapsible scaffold of 0.01 mm to 1 mm.

17. 10. The blood pump of claim 1, wherein the proximal impeller region is configured to maintain a tip clearance between the proximal impeller and the expandable and collapsible scaffold of 0.5 mm to 1 mm.

18. 2. The blood pump of claim 1, wherein the higher stiffness of the proximal impeller region is adapted to maintain concentricity between the proximal impeller and the expandable and collapsible scaffold.

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