Intravascular blood pump and method of use

Abstract

To provide additional improvements to the field of ventricular support devices and similar blood pumps for treating compromised cardiac blood flow.SOLUTION: An intravascular blood pump is provided, including a pump portion that includes a collapsible blood conduit defining a blood flow lumen between an inflow and an outflow. The pump portion includes a distal collapsible impeller axially spaced from a proximal collapsible impeller, at least a portion of each of the distal and proximal collapsible impellers disposed between the inflow and the outflow.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to the following U.S. provisional applications: Application No. 62 / 741,970, filed October 5, 2018; Application No. 62 / 778,804, filed December 12, 2018; and Application No. 62 / 905,818, filed September 25, 2019, each of which is incorporated herein by reference in its entirety for all purposes. Incorporation by Reference

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

[0002]

[0003] Patients with cardiac disease may have severely impaired ability to pump blood through their heart and vascular system, presenting substantial risks during revision procedures such as balloon angioplasty and stent delivery. There is a need for methods to improve the amount or stability of cardiac outflow in these patients, particularly during revision procedures.

[0003]

[0004] 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 patient blood flow after cardiogenic shock, treating patients associated with acute myocardial infarction (AMI), or treating decompensated heart failure. Such circulatory support can be used alone or in conjunction with drug therapy.

[0004]

[0005] An IABP is typically placed within the aorta and works by being inflated and deflated in a counterpulsating manner with cardiac contractions, one of its functions being to provide additional support to the circulatory system.

[0005]

[0006] More recently, minimally invasive rotary blood pumps have been developed that can be inserted into the body in connection with the cardiovascular system, such as pumping arterial blood from the left ventricle into the aorta to add to the natural blood pumping capacity of the left side of the patient's heart. Another known method is to pump venous blood from the right ventricle into the pulmonary artery to add to the natural blood pumping capacity of the right side of the patient's heart. The overall purpose is to reduce the workload on the patient's myocardium, such as for stabilizing the patient during medical procedures that may place additional stress on the heart, for stabilizing the patient before a heart transplant, or for continuous support of the patient.

[0006]

[0007] The smallest rotary blood pumps currently available can be inserted percutaneously into a patient's vasculature through an access sheath, thereby eliminating the need for surgical intervention, or can be inserted through a vascular access graft. One type of device is the percutaneously inserted ventricular assist device. Summary of the Invention [Problem to be solved by the invention]

[0007]

[0008] There is a need to provide further improvements in the field of ventricular assist devices and similar blood pumps for treating cardiac blood flow disorders. [Means for solving the problem]

[0008]

[0009] FIELD OF THE DISCLOSURE The present disclosure relates to fluid movement devices, such as intravascular blood pumps, and methods of their use.

[0010] One aspect of the present disclosure is an intravascular blood pump comprising a pump portion including a collapsible blood conduit defining a blood flow lumen between an inlet and an outlet, and a distal collapsible impeller axially spaced from a proximal collapsible impeller, at least a portion of each of the distal and proximal collapsible impellers disposed between the inlet and the outlet. The blood pump may include one or more stators positioned within the blood flow lumen when the pump is expanded, the stators being axially between the distal and proximal impellers. Any of the one or more stators may include one or more blood flow modifiers or blood flow altering elements (e.g., blades) axially disposed between the distal and collapsible impellers, the blood flow modifiers having at least one surface configured to alter or affect the flow of blood between the impellers.

[0009]

[0011] In this aspect, any of the flow modifiers, either alone or collectively, may be considered a stator configured to increase pressure between the first and second impellers. There may be multiple axially spaced stators, each of which may be considered to have multiple flow modifier elements (which may also be referred to as flow modifiers or derivatives thereof).

[0010]

[0012] In this aspect, any flow modifier of any stator may be disposed between the shroud and the longitudinal axis of the pump portion (even if the pump portion includes a bend formed therein). Any flow modifier may be disposed between the shroud and a central tubular element (e.g., hub), such as a tubular shaft not adapted to rotate with the impeller and / or a tubular element adapted to rotate with the impeller.

[0011]

[0013] In this embodiment, one or more blood flow modifiers may be fixed to a surface of the collapsible blood conduit.

[0014] In this aspect, one or more blood flow modifiers may extend radially inward from a surface of the collapsible blood conduit, each of the one or more blood flow modifiers having at least one axially extending surface configured to modify the flow of blood between the distal impeller and the proximal impeller.

[0012]

[0015] In this embodiment, one or more blood flow modifiers may extend radially outward from a central hub and may or may not contact the blood conduit.

[0016] In this embodiment, one or more blood flow modifiers may extend radially outward from a central hub and may or may not be secured to the blood conduit.

[0013]

[0017] In this embodiment, one or more blood flow modifiers may extend radially inward from the surface of the collapsible blood conduit, which may or may not extend to the central hub.

[0018] In this embodiment, the flow modifier or modifiers may not extend radially to the central hub.

[0014]

[0019] In this embodiment, the radially innermost region of each of the one or more blood flow modifiers may be a free region.

[0020] In this aspect, the one or more flow modifiers can be integrally formed with at least a portion of the collapsible blood conduit. The one or more flow modifiers can be integral with the scaffold of the collapsible blood conduit. The one or more flow modifiers can be biased into a deployed configuration in which they extend radially inward relative to an outer region of the scaffold.

[0015]

[0021] In this embodiment, one or more flow modifiers may extend radially to a central hub.

[0022] In this embodiment, one or more blood flow modifiers may be secured to and extend radially inward from an outer annular member that does not extend axially all the way from the inflow to the outflow, and may provide radial support to the collapsible blood conduit.

[0016]

[0023] In this embodiment, one or more of the flow modifiers may be formed from a polymeric material.

[0024] In this aspect, the one or more blood flow modifiers may have a radially outer end having at least one surface with a configuration shaped to stably align with a corresponding portion of the collapsible blood conduit. The blood pump may further include a scaffold having one or more blood flow modifier apertures therethrough, each of the radially outer ends having a configuration shaped to stably align with one of the blood flow modifier apertures. The pump may further include a membrane layer extending across the scaffold that helps secure the one or more blood flow modifiers to the apertures. The apertures may extend axially and parallel to the long axis of the scaffold. The pump may further include a self-expanding scaffold, wherein the one or more blood flow modifiers have a radially outer end with a configuration shaped to stably align with the self-expanding scaffold. The one or more blood flow modifiers may be made of a material different from the scaffold material (e.g., a polymeric material) and may be more flexible than the scaffold material.

[0017]

[0025] In this embodiment, the one or more flow modifiers may comprise at least four flow modifiers.

[0026] In this embodiment, the one or more blood flow modifiers may each be secured to one of the one or more struts, the struts defining a portion of the expandable basket in which the proximal or distal impeller is disposed. The pump portion may further include a membrane layer secured (directly or indirectly) to the expandable basket, the membrane layer at least partially defining the blood conduit. The one or more struts may be proximal struts of the expandable basket, which may be the distal or proximal basket. The struts may be at a non-orthogonal angle relative to the longitudinal axis of the pump portion at the location of the strut.

[0018]

[0027] In this aspect, the one or more blood flow modifiers may have inner free ends disposed parallel to the longitudinal axis of the pump section in which they are disposed. The collapsible blood conduit may include one or more bends formed along its length, the one or more bends being axially spaced from the one or more blood flow modifiers.

[0019]

[0028] In this embodiment, one or more blood flow modifiers may be integrally formed with at least one other component of the collapsible blood conduit.

[0029] In this embodiment, the one or more blood flow modifiers may be secured to the collapsible blood conduit and may have a radially outer section extending therefrom along a length of at least 1 mm and no more than 15 cm, optionally along a length of at least 1 mm and no more than 10 cm, optionally no more than 9 cm, no more than 8 cm, no more than 7 cm, no more than 6 cm, or no more than 5 cm.

[0020]

[0030] In this embodiment, one or more blood flow modifiers may have a radially outer section secured to and extending from the blood conduit that is longer than the radially inner edge of the blood flow modifier.

[0021]

[0031] In this embodiment, the one or more flow modifiers have a distal end surface and a proximal end surface, with at least one of the ends being tapered.

[0032] In this embodiment, the pump portion includes one or more blood flow modifiers secured to the blood conduit. The device may include a membrane that helps prevent this.

[0022]

[0033] In this embodiment, one or more of the flow modifiers may be self-expanding.

[0034] In this aspect, the at least one axially extending surface may be configured to transition the blood flow to laminar flow.

[0023]

[0035] In this embodiment, the one or more flow modifiers may be collapsible between an expanded configuration and a collapsed configuration.

[0036] In this embodiment, the one or more flow modifiers may be at least one of movable and reconfigurable between the first position and the deployed position.

[0024]

[0037] In this embodiment, the one or more flow modifiers are positioned closely adjacent to at least one of the proximal and distal impellers when the proximal and distal impellers are in the expanded configuration.

[0025]

[0038] In this embodiment, one or more flow modifiers may be closer to the proximal impeller than to the distal impeller.

[0039] In this embodiment, the flow modifier(s) may be closer to the distal impeller than to the proximal impeller.

[0026]

[0040] In this embodiment, the first end of the one or more flow modifiers can be between 0.01 mm and 20 mm from at least one of the distal impeller and the proximal impeller.

[0041] In this aspect, one or more blood flow modifiers may be secured to (optionally integral with) an annular member that provides radial support for one or more of the impeller baskets or scaffolds of the blood conduit.

[0027]

[0042] In this embodiment, the one or more blood flow modifiers may be part of a collapsible intermediate member positioned and adapted to provide radial support to the blood conduit.

[0043] In this embodiment, the one or more flow modifiers may be part of a collapsible intermediate member positioned to maintain a tip clearance between at least one of the impellers and the blood conduit.

[0028]

[0044] In this aspect, a distal region of one or more stators may be configured to act as a diffuser for the fluid in the fluid conduit to recover pressure from the distal impeller, and a proximal region of one or more fluid modifiers may be configured to act as a stator to direct flow toward the proximal impeller.

[0029]

[0045] One aspect of the present disclosure is an intravascular blood pump comprising a pump portion including: a collapsible blood conduit defining a blood flow lumen between an inflow section and an outflow section; a distal collapsible impeller axially spaced from a proximal collapsible impeller, wherein at least a portion of each of the distal and proximal collapsible impellers is disposed between the inflow section and the outflow section; and one or more stators, each including one or more blood flow modifiers axially disposed between the distal and foldable impellers, wherein each of the one or more blood flow modifiers has at least one axially extending surface configured to increase fluid pressure between the distal impeller and the proximal impeller.

[0030]

[0046] In this aspect, the at least one axially extending surface may be configured to transition the flow to laminar flow.

[0047] In this embodiment, one or more blood flow modifiers are attached to the surface of the collapsible blood conduit. The axially extending portion may be fixed to and extend radially inward therefrom.

[0031]

[0048] In this aspect, the one or more flow modifiers include any feature of any of the flow modifiers herein.

[0049] One aspect of the present disclosure is an intravascular blood pump comprising: a collapsible blood conduit defining a blood flow lumen between an inflow section and an outflow section; a proximal collapsible impeller axially spaced from a distal collapsible impeller, wherein at least a portion of each of the distal and proximal collapsible impellers is disposed between the inflow section and the outflow section; and a proximal collapsible basket in which the proximal impeller is disposed, the proximal collapsible basket providing radial support to the blood conduit at the location of the proximal impeller. an intravascular blood pump having a pump portion including a distal foldable basket, a distal foldable basket in which a distal impeller is disposed, the distal foldable basket providing radial support to the blood conduit at the location of the distal impeller, and a foldable radial support member supporting one or more of a distal region of the proximal foldable basket, a proximal region of the distal foldable basket, or a central region of the blood conduit axially disposed between the proximal basket and the distal basket.

[0032]

[0050] In this aspect, the radial support member may include an annular circumferential member and a plurality of support elements extending radially inward from the annular circumferential member, which may or may not extend to the central hub, and which may have radially inner free ends.

[0033]

[0051] In this manner, the radial support member may support the distal region of the proximal basket.

[0052] This embodiment may further include a second radial support member axially spaced from the radial support member and positioned to radially support the proximal region of the distal basket. The second radial support member may include a second annular circumferential member and a plurality of second support elements extending radially inward from the second annular circumferential member.

[0034]

[0053] In this manner, the radial support member may support the proximal region of the distal basket.

[0054] In this aspect, the collapsible radial support member may comprise a stator that includes one or more blood altering elements, such as any of the blood altering elements herein.

[0035]

[0055] One aspect of the present disclosure is an intravascular blood pump comprising: a collapsible blood conduit defining a blood flow lumen between an inflow section and an outflow section; a proximal collapsible impeller axially spaced from a distal collapsible impeller, wherein at least a portion of each of the distal and proximal collapsible impellers is disposed between the inflow section and the outflow section; a proximal collapsible basket in which the proximal impeller is disposed, wherein the proximal collapsible basket provides radial support to the blood conduit at the location of the proximal impeller; and a distal collapsible basket in which the distal impeller is disposed. An intravascular blood pump comprising: a pump portion including a distal foldable basket, wherein the distal foldable basket provides radial support to the blood conduit at the location of the distal impeller; and a foldable radial support member including an annular peripheral member and a plurality of support elements extending radially inward from the annular peripheral member, wherein the foldable radial support radially supports one or more of a distal region of the proximal foldable basket, a proximal region of the distal foldable basket, or a central region of the blood conduit axially disposed between the proximal basket and the distal basket.

[0036]

[0056] In this embodiment, the plurality of support elements may or may not extend to the central hub.

[0057] In this aspect, the plurality of support elements may have radially inner free ends.

[0037]

[0058] In this aspect, the collapsible radial support may be radially disposed within at least one of the distal region of the proximal collapsible basket, the proximal region of the distal collapsible basket.

[0038]

[0059] In this aspect, the collapsible radial support may be radially disposed within a distal region of the proximal basket, the proximal basket including a plurality of proximal struts but not a plurality of distal struts.

[0039]

[0060] In this aspect, the foldable radial support may comprise a stator including a plurality of support elements, the plurality of support elements may be configured to increase fluid pressure between the distal impeller and the proximal impeller.

[0040]

[0061] One aspect of the present disclosure is a repositionable blood pump comprising an elongate member including a pump portion, the elongate member sized for intravascular positioning in a subject, and a proximal portion from which the elongate member extends radially, the proximal portion sized to be maintained outside the subject, the proximal portion including a motor assembly coupling region configured to securely mate with a motor assembly, the proximal portion including a proximal guidewire port positioned relative to the motor assembly coupling region such that the motor assembly is securely aligned with the motor coupling region while the guidewire port is accessible for a guidewire to be advanced into the port.

[0041]

[0062] In this aspect, the proximal region may include a rotatable member in rotational communication with an impeller in the blood pump, and the motor assembly coupling region and motor assembly are configured such that the motor assembly is in rotational communication with the rotatable member when the motor assembly is securely aligned with the motor coupling region. The rotatable member may have a portion of a guidewire pathway formed therein, such that when the rotatable member is in a rotationally aligned position, the guidewire pathway extends from the portion of the guidewire pathway in the rotatable member to the guidewire port, and when the rotatable member is in a rotationally unaligned position, the guidewire pathway does not extend from the portion of the guidewire pathway in the rotatable member to the guidewire port. The portion of the guidewire pathway formed in the rotatable member may be at least partially curved, and optionally have a proximal port in the rotatable member at a radial side of the rotatable member.

[0042]

[0063] In this aspect, the guidewire port can be on the side of the proximal portion.

[0064] In this manner, the guidewire port can be configured to tightly mate with the fluid line coupler.

[0043]

[0065] This aspect may further comprise any suitable feature or element described herein.

[0066] One aspect of the present disclosure is a method of using an intravascular blood pump, the method including starting the motor to cause rotation of the impeller while the guidewire port is outside the patient and not covered by the motor assembly. This aspect may further include any suitable method step herein.

[0044]

[0067] One aspect of the present disclosure is a method of using an intravascular blood pump, the method including inserting a guidewire into a guidewire port disposed in a proximal portion of the intravascular blood pump device when the proximal portion is disposed external to the subject while the motor assembly is secured to the proximal portion of the intravascular blood pump device.

[0045]

[0068] In this aspect, the guidewire port may be on the radial side of the proximal portion, The step of inserting a guidewire may include inserting a guidewire into a radially lateral guidewire port.

[0046]

[0069] This aspect may also further include the step of repositioning the pump portion of the intravascular blood pump while the motor assembly is secured to the proximal portion.

[0070] This aspect may also include the step of removing the guidewire from the guidewire port after the inserting step while the motor assembly is secured to the proximal portion of the intravascular blood pump.

[0047]

[0071] This aspect may also include any other suitable method steps herein.

[0072] One aspect of the present disclosure is a method of using an intravascular blood pump, the method including removing a guidewire through a guidewire port disposed in a proximal portion of the intravascular blood pump device when the proximal portion is disposed external to the subject while the motor assembly is secured to the proximal portion of the intravascular blood pump device.

[0048]

[0073] In this aspect, the guidewire port may be on a radial side of the proximal portion, and the step of removing the guidewire may include removing the guidewire from the radially-side guidewire port.

[0049]

[0074] This aspect may further include either receiving outflow fluid from the proximal guidewire port into a fluid line in fluid communication with the guidewire lumen, or advancing inflow fluid from the fluid line into the guidewire port.

[0050]

[0075] One aspect of the present disclosure is an intravascular blood pump, the intravascular blood pump comprising an elongate member including a blood pump, the elongate member sized for intravascular positioning in a subject, and a proximal portion extending distally from the elongate member, the proximal portion sized to be maintained outside the subject and including a guidewire port extending through a radial side of the proximal portion. This aspect may further include any suitable features or elements described herein.

[0051]

[0076] One aspect of the present disclosure is an intravascular blood pump comprising an elongate member including a blood pump, the elongate member sized for intravascular positioning in a subject, and a proximal portion extending distally from the elongate member, the proximal portion sized to be maintained outside the subject, the proximal portion including a portion of a guidewire passageway having a bend formed therein.

[0052]

[0077] In this aspect, the proximal portion may include a rotatable component in rotational communication with an impeller in the pump portion of the elongate member, and the rotatable component may have a portion of the guidewire passageway with a bend formed therein.

[0053]

[0078] In this aspect, the proximal portion may further include a guidewire port formed in a radial side of the proximal portion.

[0079] In this aspect, the guidewire pathway may include a guidewire port and a portion of the guidewire pathway having a bend when the rotatable component is in the rotationally aligned position.

[0054]

[0080] This aspect may further include any other suitable features or elements described herein.

[0081] One aspect of the present disclosure is an intravascular blood pump, comprising an elongated member including a blood pump, the elongated member sized for intravascular positioning in a subject, and a proximal portion extending distally from the elongated member, the proximal portion sized to be maintained outside of the subject. and a proximal portion includes a rotatable component in rotational operation with the impeller within a pump portion of the elongate member, the rotatable component including a portion of a guidewire passageway, wherein rotation of the component causes misalignment or alignment between the portion of the guidewire passageway and a second portion of the guidewire passageway formed within a second component of the proximal portion that is not in rotational operation with the impeller. This aspect may further include any other suitable features or elements described herein.

[0055]

[0082] One aspect of the present disclosure is an intravascular blood pump comprising an elongate member including a blood pump, the elongate member sized for intravascular positioning in a subject, and a proximal portion extending distally from the elongate member, the proximal portion sized to be maintained outside the subject, the proximal portion including a guidewire access port configured for coupling to a connector of a fluid line when a guidewire is not within the access port such that fluid can be delivered from the fluid line into the guidewire port or received from the guidewire port into the fluid line.

[0056]

[0083] In this aspect, the guidewire port may be disposed on a radial side of the proximal portion. The connector may include a luer fitting.

[0084] In this aspect, the guidewire port may be part of a guidewire passageway that extends distally beyond the distal end of the impeller within the pump portion of the blood pump.

[0057]

[0085] In this aspect, the guidewire pathway may further include a guidewire port, and the guidewire pathway further includes a portion having a curved configuration, the curved configuration being the proximal portion.

[0086] This aspect may further comprise any other suitable features or elements described herein.

[0058]

[0087] One aspect of the present disclosure is an intravascular blood pump comprising: an expandable blood flow conduit having a distal end and a proximal end; and at least one impeller radially disposed within the conduit, wherein the conduit has a central region, a proximal region proximal to the central region, and a distal region distal to the central region, wherein the central region has greater flexibility than both the proximal and distal regions, and wherein the distal and proximal regions are between the conduit proximal and distal ends.

[0059]

[0088] In this aspect, the impeller may be a proximal impeller, radially within the proximal region, and the blood pump further comprises a distal impeller distal to the proximal impeller, the distal impeller being radially within the distal region, and the distal and proximal impellers do not extend axially into the central region.

[0060]

[0089] In this aspect, the conduit may include a support structure, optionally extending the entire length of the fluid lumen.

[0090] This aspect may further comprise any other suitable features or elements described herein.

[0061]

[0091] This aspect includes a method of positioning the pump of this aspect, the method including positioning the distal region distal to the aortic valve and the proximal region proximal to the valve.

[0062]

[0092] One aspect of the present disclosure is an intravascular blood pump including an outer conduit having a distal end and a proximal end, the pump including a support structure comprising a plurality of elongated elements disposed in a proximal region of the support structure, the plurality of elongated elements each having a transition portion where a respective arm transitions from a larger diameter region to a smaller diameter region, and at the transition portion, each of the respective arms has a perpendicular section relative to a longitudinal axis of the outer housing. and an impeller disposed at least partially within the conduit.

[0063]

[0093] In this embodiment, the plurality of elongate elements have a bend region adjacent to the vertical section, where the bend transitions the vertical section to one of the larger diameter region and the smaller diameter region. The plurality of elongate elements can have a second bend region adjacent to the vertical section, where the second bend region transitions the vertical section to the other of the larger diameter region and the smaller diameter region.

[0064]

[0094] In this aspect, the elongate elements are configured such that they do not affect or alter fluid outflow in any significant way, as would be understood by one of ordinary skill in the art. This aspect may further comprise any other suitable features or elements described herein.

[0065]

[0095] One aspect of the present disclosure is an intravascular blood pump including an outer blood flow conduit defining a fluid lumen having a distal end and a proximal end, the pump also including a support structure having a proximal region with a plurality of apexes pointing proximally, a first set of the plurality of apexes extending to a first axial position and a second set of the plurality of apexes extending further proximally than the first axial position, and an impeller disposed radially within the fluid lumen.

[0066]

[0096] In this embodiment, the second set of apices can be integrally formed with the proximal struts, each having a vertical section that transitions the strut from a larger diameter section to a smaller diameter section. This embodiment can include any other suitable feature or element described herein.

[0067]

[0097] One aspect of the present disclosure is an intravascular blood pump including an outer expandable blood flow conduit defining a fluid lumen having a distal end and a proximal end, at least one of the distal end and the proximal end of the fluid lumen having a radially outward flared configuration, the pump further including a support structure, and the pump portion also including an impeller radially disposed within the outer expandable blood flow conduit.

[0068]

[0098] In this aspect, the support structure may include a plurality of struts, with the proximal end of the fluid lumen flaring and disposed distal to the transition region in each of the plurality of struts.

[0099] In this aspect, the proximal end of the fluid lumen may be flared, with the proximal end of the impeller extending further proximally than the proximal end of the lumen.

[0069]

[0100] In this embodiment, at least one splayed configuration may be supported by a support structure.

[0101] This aspect may further include any other suitable features or elements described herein.

[0070]

[0102] One aspect of the present disclosure is an intravascular blood pump including an outer expandable conduit defining a fluid lumen having a distal end and a proximal end, the pump also including a support structure with a first portion having a proximal end and a distal end, the first portion including a plurality of elongated elements, each of the plurality of elongated elements having a helical configuration, and an impeller disposed radially within the fluid lumen.

[0071]

[0103] In this embodiment, the first portion may axially overlap at least a portion of the impeller.

[0104] In this embodiment, the first portion may completely overlap the impeller axially.

[0072]

[0105] In this aspect, when viewed from the side, each of the plurality of elongated elements may follow the helical configuration of the at least one impeller blade, although following in this regard does not require the helical configuration to have the same pitch as the at least one impeller blade.

[0073]

[0106] In this embodiment, when viewed from the side, the multiple elongate elements may form a larger angle with the longitudinal axis of the fluid lumen formed by the multiple elongate elements in the areas immediately proximal and immediately distal to the first portion (greater curvature in the first portion relative to the longitudinal axis).

[0074]

[0107] In this embodiment, when viewed from the side, each of the elongate elements may have a tangent that forms an angle with a tangent to the helical impeller blade of 45 degrees or less, optionally 35 degrees or less, optionally 20 degrees or less, optionally 15 degrees or less, optionally 10 degrees or less (see FIG. 23).

[0075]

[0108] In this embodiment, when viewed from the side, each of the elongated elements may have a tangent that forms an angle of 45 degrees or less, optionally 35 degrees or less, optionally 20 degrees or less, optionally 15 degrees or less, optionally 10 degrees or less with the camber line of the helical blade where the elongated element and the helical blade axially overlap (see, e.g., FIG. 23 ).

[0076]

[0109] In this embodiment, at least one of the plurality of elongate elements having a helical configuration does not make a complete rotation (ie, 360 degrees in end view) around the support structure.

[0110] In this embodiment, at least one of the plurality of elongate elements having a helical configuration may make a full rotation (ie, 360 degrees in end view) around the support structure.

[0077]

[0111] In this aspect, the support structure may further include a second portion having a second plurality of elongated elements, each of which may have a helical configuration. The second portion may be axially spaced from the first portion. The second portion may at least partially axially overlap the impeller. The second portion may at least partially overlap a second impeller that is axially spaced from the impeller. The second portion may have the same configuration as the first portion.

[0078]

[0112] In this aspect, each elongate element may be a connecting element to an adjacent section of the support structure.

[0113] In this embodiment, the elongate elements may each have a first end coupled to a first adjacent section of the support structure and a second end coupled to a second adjacent section of the support structure.

[0079]

[0114] In this embodiment, the first portion may have an axial length of 1 to 20 mm.

[0115] In this aspect, the first portion may have an axial length that is between 1 and 100%, optionally between 1 and 80%, optionally between 1 and 70%, optionally between 1 and 60%, optionally between 1 and 50%, optionally between 1 and 40%, optionally between 1 and 30% of the length of the impeller.

[0080]

[0116] In this aspect, the first portion may overlap axially with the impeller along at least 100% of the impeller length, optionally no more than 90%, optionally no more than 80%, optionally no more than 70%, optionally no more than 60%, optionally no more than 50%, optionally no more than 40%, optionally no more than 30% of its length.

[0081]

[0117] One aspect of the present disclosure is a method for collapsing a pump portion of a blood pump, the method including rotating an elongated member to which the collapsible pump portion is secured when the elongated member is disposed within a patient.

[0082]

[0118] In this embodiment, the rotation may encourage folding of one or more blades, optionally helical blades, of the impeller within the pump portion.

[0119] In this embodiment, this rotation may cause the support structure of the pump section to apply a force against one or more blades (optionally helical blades) of an impeller within the pump section.

[0083]

[0120] In this aspect, the method may further include applying a tensile force to the elongate member either simultaneously with the rotation or occurring at a separate time.

[0121] One aspect of the present disclosure is a method of folding an impeller of a pump portion of a blood pump, comprising folding a support structure on which the impeller is disposed, wherein the folding step applies a radially inward folding force to the helical blades of the impeller by elongated members of the support structure (optionally integrally formed with the rest of the scaffold pattern, i.e., not a separate component coupled to the scaffold pattern) having a helical configuration, wherein the radially inward folding force from the elongated members having a helical configuration ensures that the helical blades fold in a particular orientation relative to a central support structure, optionally a hub.

[0084]

[0122] In this aspect, the folding step may include applying a radially inward folding force to the helical blades of the impeller by a plurality of elongated members of the support structure, each having a helical configuration.

[0085]

[0123] In this aspect, the folding step may include applying at least one of a tensioning force and a rotational force to the elongate member to which the support structure is coupled.

[0124] In this aspect, the method may further include any other suitable method step(s) herein.

[0086]

[0125] One aspect of the present disclosure is an intravascular blood pump comprising: an outer expandable blood flow conduit defining a fluid lumen having a distal end and a proximal end; an impeller radially disposed within the fluid lumen, the impeller coupled to a rotatable shaft; a rotatable drive member (e.g., a drive cable) in operative communication with the rotatable shaft, the rotatable drive member being rotatable in response to an energy source (e.g., a motor); and a speed increaser operatively interacting with the drive member and the rotatable shaft, the speed increaser causing the rotatable shaft to rotate faster than the rotatable drive member.

[0087]

[0126] In this aspect, the speed increaser may include a first gear coupled to the drive member and a second gear coupled to the rotatable shaft, the first and second gears interacting with one another and the second gear having a smaller diameter than the first gear.

[0088]

[0127] In this aspect, the rotatable drive member may be coaxial with the rotatable shaft.

[0128] In this aspect, the rotatable drive member may not be coaxial with the rotatable shaft.

[0089]

[0129] In this aspect, the speed increaser may comprise a planetary gearbox.

[0130] In this aspect, the speed increaser may comprise a shaft that is different from the drive member and the rotatable shaft. [Brief explanation of the drawings]

[0090] [Figure 1]

[0131] FIG. 1 is a side view of an exemplary pump portion including a conduit, multiple impellers, and an expandable member. [Figure 2]

[0132] FIG. 1 is a side view of an exemplary pump portion including a conduit, multiple impellers, and multiple expandable members. [Figure 3A]

[0133] 1 illustrates an exemplary pump portion including a conduit, multiple impellers, and multiple expandable members. [Figure 3B] 1 illustrates an exemplary pump portion including a conduit, multiple impellers, and multiple expandable members. [Figure 3C] 1 illustrates an exemplary pump portion including a conduit, multiple impellers, and multiple expandable members. [Figure 3D] 1 illustrates an exemplary pump portion including a conduit, multiple impellers, and multiple expandable members. [Figure 4]

[0134] 10A-10C illustrate an exemplary arrangement of a pump portion including a conduit, multiple expandable members, and multiple impellers. [Figure 5]

[0135] 1 illustrates an exemplary pump portion. [Figure 6A]

[0136] 1 illustrates at least a portion of an exemplary medical device having a pump portion in which at least two different impellers can be rotated at different speeds. [Figure 6B]

[0137] 1 illustrates at least a portion of an exemplary medical device having a pump portion in which at least two different impellers can be rotated at different speeds. [Figure 6C]

[0138] 1A-1C illustrate at least a portion of an exemplary medical device having a pump portion with at least two impellers of different pitches. [Figure 7]

[0139] 1 illustrates at least a portion of an exemplary medical device having a pump portion. [Figure 8]

[0140] 1 illustrates a pump section having multiple impellers with bends formed therein between adjacent impellers; FIG. [Figure 9]

[0141] FIG. 1 illustrates a pump section having multiple impellers. [Figure 10]

[0142] FIG. 1 is a side view of a portion of a fluid movement device including a pump portion including a central or intermediate member axially spaced between first and second impellers. [Figure 11A]

[0143] FIG. 11A is a diagram illustrating an exemplary central or intermediate member. [Figure 11B] FIG. 11B is a diagram illustrating an exemplary central or intermediate member. [Figure 11C] FIG. 11C is a diagram illustrating an exemplary central or intermediate member. [Figure 12A]

[0144] FIG. 1 is a diagram of an exemplary medical device including a pump portion or a portion of a pump portion, including a first central (intermediate) member and a second central (intermediate) member. [Figure 12B]FIG. 1 is a diagram of an exemplary medical device including a pump portion or a portion of a pump portion, including a first central (intermediate) member and a second central (intermediate) member. [Figure 12C] FIG. 1 is a diagram of an exemplary medical device including a pump portion or a portion of a pump portion, including a first central (intermediate) member and a second central (intermediate) member. [Figure 12D] FIG. 1 is a diagram of an exemplary medical device including a pump portion or a portion of a pump portion, including a first central (intermediate) member and a second central (intermediate) member. [Figure 13A]

[0145] FIG. 13A is a diagram of an exemplary center or intermediate member. [Figure 13B] FIG. 13B is a diagram of an exemplary center or intermediate member. [Figure 13C] FIG. 13C is a diagram of an exemplary center or middle member. [Figure 14A]

[0146] FIG. 14A illustrates an exemplary blood pump in which at least the components shown are non-collapsible and are not collapsed for delivery. [Figure 14B] FIG. 14B is a diagram illustrating an exemplary blood pump in which at least the components shown are non-collapsible and are not collapsed for delivery. [Figure 15A]

[0147] 1 illustrates an exemplary blood pump including a guidewire passage and at least one fluid purge passage. [Figure 15B] 1 illustrates an exemplary blood pump including a guidewire passage and at least one fluid purge passage. [Figure 15C] 1 illustrates an exemplary blood pump including a guidewire passage and at least one fluid purge passage. [Figure 15D] 1 illustrates an exemplary blood pump including a guidewire passage and at least one fluid purge passage. [Figure 16A]

[0148] 1 illustrates an exemplary blood pump including a guidewire passage and at least two fluid purge passages that are not in fluid communication. [Figure 16B] 1 illustrates an exemplary blood pump including a guidewire passage and at least two fluid purge passages that are not in fluid communication. [Figure 17A]

[0149] 10A-10C illustrate an exemplary pump portion including an expandable housing, including an exemplary scaffold design. [Figure 17B] 10A-10C illustrate an exemplary pump portion including an expandable housing, including an exemplary scaffold design. [Figure 17C] 10A-10C illustrate an exemplary pump portion including an expandable housing, including an exemplary scaffold design. [Figure 17D] 10A-10C illustrate an exemplary pump portion including an expandable housing, including an exemplary scaffold design. [Figure 17E] 10A-10C illustrate an exemplary pump portion including an expandable housing, including an exemplary scaffold design. [Figure 17F] 10A-10C illustrate an exemplary pump portion including an expandable housing, including an exemplary scaffold design. [Figure 18A]

[0150] FIG. 18A is a diagram illustrating an exemplary scaffold design. [Figure 18B] FIG. 18B is a diagram illustrating an exemplary scaffold design. [Figure 19A]

[0151] FIG. 19A is a diagram illustrating an exemplary scaffold design. [Figure 19B] FIG. 19B is a diagram illustrating an exemplary scaffold design. [Figure 20]

[0152] FIG. 1 illustrates an exemplary scaffold design. [Figure 21A]

[0153] FIG. 1 illustrates an exemplary scaffold design. [Figure 21B]FIG. 1 illustrates an exemplary scaffold design. [Figure 21C] FIG. 1 illustrates an exemplary scaffold design. [Figure 22A]

[0154] FIG. 22A is a diagram illustrating an exemplary scaffold design. [Figure 22B] FIG. 22B is a diagram illustrating an exemplary scaffold design. [Figure 23]

[0155] 10A-10C illustrate a portion of an expandable housing with a fluid lumen having an outwardly flared configuration at at least one end of the fluid lumen. [Figure 24]

[0156] FIG. 1 illustrates an outer housing including one or more blades extending radially inward. [Figure 25]

[0157] FIG. 10 illustrates a proximal portion of an exemplary pump portion, where the pump portion includes one or blades sized and configured to match a portion of the scaffold. [Figure 26A]

[0158] FIG. 26A illustrates a portion of an exemplary blood pump along with an exemplary speed increaser assembly and mechanism that may be incorporated within the blood pump. [Figure 26B] FIG. 26B illustrates a portion of an exemplary blood pump along with an exemplary speed increaser assembly and mechanism that may be incorporated within the blood pump. [Figure 27]

[0159] 10A-10C illustrate an exemplary pump portion adapted, optionally with at least one elongated member, so that the pump portion can be deflected at least at one location along the length of the pump portion. [Figure 28A]

[0160] 1 illustrates an exemplary series of steps that may be performed according to an exemplary method of using an exemplary blood pump. [Figure 28B] 1 illustrates an exemplary series of steps that may be performed according to an exemplary method of using an exemplary blood pump. [Figure 28C] 1 illustrates an exemplary series of steps that may be performed according to an exemplary method of using an exemplary blood pump. [Figure 28D] 1 illustrates an exemplary series of steps that may be performed according to an exemplary method of using an exemplary blood pump. [Figure 28E] 1 illustrates an exemplary series of steps that may be performed according to an exemplary method of using an exemplary blood pump. [Figure 28F] 1 illustrates an exemplary series of steps that may be performed according to an exemplary method of using an exemplary blood pump. [Figure 29A]

[0161] FIG. 29A is a diagram illustrating an exemplary collapsible flow-altering element that may be part of a pump portion, optionally disposed between two collapsible impellers. [Figure 29B] FIG. 29B is a diagram illustrating an exemplary foldable flow-altering element that may be part of the pump portion, optionally disposed between two foldable impellers. [Figure 30A]

[0162] 10A-10C illustrate an exemplary blood flow conduit support member including a plurality of apertures therein sized and configured to receive and align with one or more flow-altering elements. [Figure 30B]

[0163] FIG. 10 is an end view of an exemplary support member having a plurality of flow-modifying elements each disposed in one of a plurality of support member apertures. [Figure 31A]

[0164] FIG. 31A is a diagram illustrating an exemplary flow-altering element that may be sized and configured to be advanced through a conduit support member aperture such as that in FIGS. 30A and 30B. [Figure 31B] FIG. 31B is a diagram illustrating an exemplary flow-altering element that may be sized and configured to be advanced through a conduit support member aperture such as that in FIGS. 30A and 30B. [Figure 32A]

[0165] FIG. 32A illustrates an exemplary conduit support member including a plurality of flow modifying elements integrally formed with the support member and capable of self-deploying into a radially inward extending active flow modifying configuration. [Figure 32B] FIG. 32B illustrates an exemplary conduit support member including a plurality of flow modifying elements integrally formed with the support member and capable of self-deploying into a radially inward extending active flow modifying configuration. [Figure 32C] FIG. 32C illustrates an exemplary conduit support member including a plurality of flow modifying elements integrally formed with the support member and capable of self-deploying into an active flow modifying configuration extending radially inward. [Figure 33A]

[0166] FIG. 33A is a diagram illustrating an exemplary pump section that optionally includes a plurality of flow-modifying elements 445 secured to the posts of the pump section. [Figure 33B] FIG. 33B is a diagram illustrating an exemplary pump section that optionally includes a plurality of flow-modifying elements 445 secured to the posts of the pump section. [Figure 34]

[0167] FIG. 2 is a side view of an exemplary flow-modifying element disposed between a first impeller and a second impeller. [Figure 35A]

[0168] FIG. 35A is a side view of an exemplary flow-modifying element (eg, a diffuser in the illustration). [Figure 35B] FIG. 35B is a top view of an exemplary flow-altering element (eg, a diffuser in the figure) illustrating the configuration of the diffuser from above as well as the fluid direction relative to the diffuser. DETAILED DESCRIPTION OF THE INVENTION

[0091]

[0169] The present disclosure relates to medical devices, systems, and methods of use and manufacture. The medical devices herein may include a pump portion adapted and configured to be disposed within a physiological vessel, the pump including one or more components that act on a fluid. For example, the pump portion herein may include one or more impellers configured such that when rotated, they promote movement of a fluid, such as blood.

[0092]

[0170] 1 is a side view illustrating a distal portion of an exemplary intravascular fluid pump including a pump portion 1600, which includes a proximal impeller 1606 and a distal impeller 1616, both of which are in communication with a drive cable 1612. 1 is in an extended configuration but is adapted to collapse into a delivery configuration so that it can be delivered with a lower profile. The impeller may be in direct or indirect rotational communication with a drive cable 1612. The drive cable 1612 is in communication with an external motor (not shown) and extends through the elongated shaft 1610. The terms "pump portion" and "working portion" (or derivatives thereof) may be used interchangeably herein unless indicated to the contrary. For example, without limitation, "pump portion" 1600 may also be referred to herein as "working portion."

[0093]

[0171] 2 is a side view illustrating a deployed configuration (shown outside the body) of a distal portion of an exemplary embodiment of a fluid movement system. The exemplary system 1100 includes a pump portion 1104 (which may be referred to herein as a pump portion, as specified herein) and an elongated portion 1106 extending from the pump portion 1104. The elongated portion 1106 may extend to a more proximal region of the system, not shown for clarity, which may include, for example, a motor. The pump portion 1104 includes a first expandable member 1108 and a second expandable member 1110 that are axially spaced apart along a longitudinal axis LA of the pump portion 1104. Axial spaced apart in this context refers to the first expandable member being axially spaced apart entirely from the second expandable member along the longitudinal axis LA of the pump portion 1104. A first end 1122 of the first expandable member 1108 is axially spaced from a first end 1124 of the second expandable member 1110. Some "expandable members" herein may also be referred to herein as baskets.

[0094]

[0172] The first and second expandable members 1108 and 1110 generally each include a plurality of elongated sections disposed relative to one another to define a plurality of apertures 1130, only one of the plurality of apertures being labeled in the second expandable member 1110. The expandable members may have a variety of configurations and may be constructed in a variety of ways, such as, but not limited to, any of the configurations or structures in U.S. Pat. No. 7,841,976 or the tubes in U.S. Pat. No. 6,533,716, which are described as self-expanding metallic endoprosthesis materials. For example, but not limited to, one or both of the expandable members may have a braided structure or may be formed at least in part by laser cutting a tubular element.

[0095]

[0173] The pump portion 1104 also includes a blood flow conduit 1112, which in this embodiment is supported by the first expandable member 1108 and the second expandable member 1110. The conduit 1112 also extends axially between the first expandable member 1108 and the second expandable member 1110 in the deployed configuration. A central region 1113 of the conduit 1112 spans an axial distance 1132 that is free of the first and second expandable members 1108 and 1110 in the pump portion. 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 as distally as the distal end 1125 of the second expandable member 1110, and the proximal end of the conduit 1128 does not extend as proximally as the proximal end 1121 of the first expandable member 1108.

[0096]

[0174] 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 physically contacts the expandable member. However, even if not directly attached, the term coupled in this context refers to the conduit and expandable member being joined together so that the expandable member can expand or collapse, and the conduit also begins to transition to a different configuration and / or size. Thus, coupled in this context refers to the conduit moving as the expandable member to which it is coupled transitions between its expanded and collapsed configurations. A conduit in this specification is considered to create a passageway through which fluid is moved and may be defined by one or more components of the pump portion.

[0097]

[0175] Any of the conduits herein may be deformable to some extent. For example, the conduit 1112 includes 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, for example, in response to forces from the valve tissue (e.g., the valve leaflets) or replacement valve during use when the pump portion 1104 is deployed toward the configuration shown in FIG. 2 . The conduit, in some embodiments, may be tensioned between the expandable members. The conduit may alternatively be designed with slack that induces greater compliance. This may be desirable when the pump portion is disposed 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 include 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, urethane rubber, silicone rubber, acrylic rubber, expanded polytetrafluoroethylene, polyethylene, polyethylene terephthalate, or any combination thereof.

[0098]

[0176] Any of the conduits herein may have a thickness of, for example, 12.7 to 508 micrometers (0.5 to 20 thousandths of an inch (thou)), 25.4 to 381 micrometers (1 to 15 thou), or 38.1 to 381 micrometers (1.5 to 15 thou), 38.1 to 254 micrometers (1.5 to 10 thou), or 50.8 to 254 micrometers (2 to 10 thou).

[0099]

[0177] Any of the conduits herein, or at least a portion of the conduits, may be blood-impermeable. In FIG. 2, pump portion 1104 includes a lumen extending from distal end 1126 of conduit 1112 and extending to proximal end 1128 of conduit 1112. The lumen is defined by conduit 1112 in central region 1113, but can be considered to be defined by both the conduit and portions of the expandable member in regions axially adjacent to central region 1113. However, in this embodiment, it is the conduit material that causes the lumen to exist and prevents blood from passing through the conduit.

[0100]

[0178] Any of the conduits herein secured to one or more expandable members may be secured such that the conduit is disposed radially outward of one or more expandable members, radially inward of one or more expandable members, or both, unless indicated to the contrary, and the expandable members may be impregnated with the conduit material.

[0101]

[0179] The proximal and distal expandable members help maintain the conduit in an open configuration by providing radial support to the conduit while also creating a working environment for the impellers, described below. When in the deployed configuration, each expandable member is maintained in a spaced-apart relationship with respect to its respective impeller, allowing the impeller to rotate within the expandable member without contacting the expandable member. The pump portion 1104 includes 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, even though they are distinct impellers, are coupled to a common drive mechanism (e.g., drive cable 1117) such that when the drive mechanism is actuated, the two impellers rotate together. In this deployed configuration, the impellers 1116 and 1118 are axially spaced apart along the longitudinal axis LA in the same manner as the expandable members 1108 and 1110 are axially spaced apart.

[0102]

[0180] Impellers 1116 and 1118 are also axially within the ends of expandable members 1108 and 1110, respectively (and radially within expandable members 1108 and 1110). In addition, the impellers herein may be considered to be axially within the expandable member even if the expandable member includes struts (e.g., tapered struts when viewed from the side) that extend from a central region of the expandable member toward the longitudinal axis of the pump portion. In FIG. 2, the second expandable member 1110 extends from a first end 1124 (proximal end) to a second end 1125 (distal end).

[0103]

[0181] 2, a distal portion of impeller 1118 extends distally beyond distal end 1126 of conduit 1112, and a proximal portion of impeller 1116 extends proximally beyond proximal end 1128 of conduit 1112. In this illustration, portions of each impeller are axially within the conduit in this deployed configuration.

[0104]

[0182] 2, impellers 1116 and 1118 are in communication with a common drive mechanism 1117; in this embodiment, the impellers are each coupled to drive mechanism 1117 that extends through shaft 1119 and pump portion 1104. Drive mechanism 1117 may be, for example, an elongated drive cable that, when rotated, rotates the impellers. In this example, as shown, drive mechanism 1117 extends to and is axially fixed relative to distal tip 1114, but is adapted to rotate relative to distal tip 1114 when actuated. Thus, in this embodiment, impeller and drive mechanism 1117 rotate together when the drive mechanism is rotated. Any number of known mechanisms may be used to rotate the drive mechanism, such as with a motor (e.g., an external motor).

[0105]

[0183] The expandable member and conduit are not in rotational communication with the impeller and drive mechanism. 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 also coupled to the proximal end 1124 of the distal expandable member 1110. The drive mechanism 1117 therefore rotates within and relative to the central tubular member 1133. The 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 a distal tip 1114, as shown. A drive mechanism 1117 is adapted to rotate relative to the tip 1114, but is axially fixed relative to the tip 1114.

[0106]

[0184] Pump portion 1104 is adapted and configured to be collapsed to a smaller profile than its deployed configuration (shown in FIG. 2). This allows pump portion 1104 to be delivered using a lower profile delivery device (smaller French size) than would be required if pump portion 1104 were not collapsed. Although not specifically described herein, either the expandable member and the impeller may be adapted and configured to be collapsed to a smaller delivery configuration to some extent.

[0107]

[0185] The pump portions herein may be collapsed into a collapsed delivery configuration using conventional techniques, such as with an outer sheath that is movable relative to the pump portion (e.g., by axially moving one or both of the sheath and the pump portion). For example, without limitation, any of the systems, devices, or methods shown in the following references may be used to facilitate the collapse of the pump portions herein: U.S. Pat. No. 7,841,976 or U.S. Pat. No. 8,052,749, the disclosures of which are incorporated herein by reference for all purposes.

[0108]

[0186] Figures 3A-3E show an exemplary pump portion that is similar in some respects to the pump portion shown in Figure 2. Pump portion 340 is similar to pump portion 1104 in that it includes two expandable members that are axially spaced apart from one another when the pump portion is expanded, and a conduit extending between the two expandable members. Figure 3A is a perspective view, Figure 3B is a side cross-sectional view, and Figures 3C and 3D are enlarged side cross-sectional views of the area seen in Figure 3B.

[0109]

[0187] The pump portion 340 includes a proximal impeller 341 and a distal impeller 342 coupled to and in communication with a drive cable that defines a lumen. The lumen can be sized to accommodate a guidewire that can be used for delivery of the pump portion to a desired location. The drive cable, in this embodiment, includes a first section 362 (e.g., wound material), a second section 348 (e.g., tubular member) to which the proximal impeller 341 is coupled, a third section 360 (e.g., wound material), and a fourth section 365 (e.g., tubular material) to which the distal impeller 342 is coupled. All of the drive cable sections have the same inner diameter, resulting in a constant inner diameter for the lumen. The 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 pump portion, allowing the pump portion to be advanced, for example, over a guidewire for positioning the pump portion. In this embodiment, the second and fourth regions may be stiffer than the first and third regions, for example, the second and fourth regions may be tubular and the first and third regions may be wound material to provide less stiffness.

[0110]

[0188] Pump portion 340 includes a blood flow conduit, a proximal expandable member 343, and a distal expandable member 344, each of which extends radially outside one of the impellers. The expandable members have distal and proximal ends that also extend axially beyond the distal and proximal ends of the impellers, which can be seen in FIGS. 3B-3D. The pump also includes a conduit 356 having a proximal end 353 and a distal end 352. Each of the two expandable members includes a plurality of proximal and distal struts. The proximal struts within proximal expandable member 343 extend to and are secured to a shaft section 345, which is coupled to a bearing 361 through which a drive cable extends and is configured and sized to rotate. The distal struts of the proximal expandable member 343 extend to and are secured to a proximal region (in this case, the proximal end) of a central tubular member 346 that is axially disposed between the expandable members. The proximal end of the central tubular member 346 is coupled to a bearing 349, as shown in FIG. 3C, through which the drive cable extends and rotates. The proximal struts of the distal expandable member 344 extend to and are secured to a distal region (in this case, the distal end) of the central tubular member 346. A bearing 350 is also coupled to the distal region of the central tubular member 346, as shown in FIG. 3D. The drive cable extends through and rotates relative to bearing 350. The distal struts of the distal expandable member extend to and are secured to a shaft section 347 (see FIG. 3A), which may be considered to be part of the distal tip. Shaft section 347 is coupled to bearing 351 (see FIG. 3D), through which the drive cable extends and rotates relative to. The distal tip also includes bearing 366 (see FIG. 3D), which may be a thrust bearing. Working portion 340 may be similar in some respects to or the same as working portion 1104, even if not explicitly included in the description. In this embodiment, conduit 356 extends at least to the end of the impeller, unlike working portion 1104. Either embodiment may be modified so that the conduit extends to a position as specified in other embodiments. In some embodiments, section 360 may be a tubular section instead of wound.

[0111]

[0189] In alternative embodiments, at least a portion of any of the impellers herein may extend outside of the fluid lumen. For example, only a portion of the impeller may extend proximally or The impeller may extend beyond the end of the fluid lumen in either a proximal or distal direction. In some embodiments, the portion of the impeller that extends outside of the fluid lumen is the proximal portion of the impeller, including the proximal end (see, e.g., the proximal impeller in FIG. 2). In some embodiments, the portion of the impeller that extends outside of the fluid lumen is the distal portion of the impeller, including the distal end (see, e.g., the distal impeller in FIG. 2). When the disclosure herein refers to an impeller extending outside (or beyond) the fluid lumen, it is meant to refer to the relative axial position of the components, which is most easily visible in a side or top view, such as FIG. 2.

[0112]

[0190] However, a second impeller at another end of the fluid lumen may not extend beyond the fluid lumen. For example, an illustrative alternative design may include a proximal impeller (as in 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. 3B). Alternatively, the distal end of the distal impeller may extend distally beyond the distal end of the fluid lumen, but the proximal end of the proximal impeller does not extend proximally beyond the proximal end of the fluid lumen. In any of the pump sections herein, none of the impellers may extend beyond the end of the fluid lumen.

[0113]

[0191] Although specific exemplary locations may be shown herein, the fluid pump may be capable of being used in a variety of locations within the body. Some exemplary locations for placement include placement near the aortic or pulmonary valve, such as spanning the valve and being positioned on one or both sides of the valve, as well as, in the case of the aortic valve, optionally including a portion positioned within the ascending aorta. In some other embodiments, the pump may be positioned further downstream, such as being disposed within the descending aorta during use, for example.

[0114]

[0192] FIG. 4 illustrates an exemplary placement of pump portion 1104 from system 1000 from FIG. 2 and also illustrates an exemplary placement location for any of the pump portions herein. One difference shown in FIG. 4 is that the conduit extends at least to the end of the impeller, as in FIGS. 3A-3D . FIG. 4 shows pump portion 1104 in a deployed configuration positioned in place across (i.e., straddling) the aortic valve. Pump portion 1104 can be delivered as shown, for example, without limitation, via femoral artery access (a known access procedure). Although not shown for clarity, system 1000 can also include an outer sheath or shaft over which pump portion 1104 is disposed 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”) to enable deployment and expansion of pump portion 1104. For example, the sheath can be retracted to allow expansion of the second expandable member 1110, with continued proximal movement allowing the first expandable member 1108 to expand.

[0115]

[0193] In this embodiment, the second expandable member 1110 is expanded and positioned in a deployed configuration within the left ventricle "LV" such that the distal end 1125 is distal to the aortic valve leaflets "VL" as well as distal to the annulus. The proximal end 1124 is also positioned distal to the leaflets VL, although in some methods, the proximal end 1124 may extend axially slightly within the leaflets VL. This embodiment is an example of how at least half of the second expandable member 1110 resides within the left ventricle when measured along its length (measured along the longitudinal axis). As also shown, this is also an example of how the entire second expandable member 1110 resides within the left ventricle. This is also an example of how at least half of the second impeller 1118 is positioned within the left ventricle, and also an embodiment in which the entire second impeller 1118 is positioned within the left ventricle.

[0116]

[0194] Continued retraction of the outer shaft or sheath (and / or distal movement of the working end 1104 relative to the outer sheath or shaft) causes the central region 1113 to release and expand. Continue releasing the conduit 1112 until it is fully opened. Expansion of the expandable members 1108 and 1110 causes the conduit 1112 to assume an 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 the conduit will assume a deployed, more open configuration when the working end is deployed. At least a portion of the central region 1113 of the conduit 1112 is positioned in the aortic valve coaptation region. In FIG. 3, there is a short length of the central region 1113 that extends distally beyond the valve leaflets VL, but at least some portion of the central region 1113 is axially within the valve leaflets.

[0117]

[0195] 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 positioned in a deployed configuration (as shown) such that the proximal end 1121 is within the ascending aorta AA and proximal to the valve leaflets "VL." The distal end 1122 is also positioned proximal to the valve leaflets VL, although in some methods, the distal end 1122 may extend axially slightly within the valve leaflets VL. This embodiment is an example of how at least half of the first expandable member 1110 resides within the ascending aorta as measured along its length (measured along the longitudinal axis). As also shown, this is also an example of how the entire first expandable member 1110 resides within the AA. This is also an example of how at least half of the first impeller 1116 is positioned within the AA, and also an embodiment where the entire first impeller 1116 is positioned within the AA.

[0118]

[0196] At any time during or after deployment of the pump portion 1104, the position of the pump portion can be accessed in some manner, such as under fluoroscopy. The position of the pump portion can be adjusted at any time during or after deployment. For example, after the second expandable member 1110 is released but before the first expandable member 1108 is released, the pump portion 1104 can be moved axially (distally or proximally) to reposition the pump portion. Additionally, for example, the pump portion can be repositioned after the entire working portion is released from the sheath to a desired final position.

[0119]

[0197] It should be understood that the positions of the components (relative to the anatomy) shown in FIG. 4 are considered exemplary final positions for the different components of the working portion 1104, even if there is repositioning that occurs after initial deployment.

[0120]

[0198] One or more expandable members herein may be configured to be and may be expanded in a variety of ways, such as self-expansion, mechanical actuation (e.g., one or more axially directed forces on the expandable member, expanded by a separate balloon positioned axially within the expandable member and inflated to push radially outward against the expandable member), or a combination thereof.

[0121]

[0199] As used herein, expansion generally refers to a reconfiguration to a larger profile having a larger radially outermost dimension (relative to the longitudinal axis), regardless of the particular manner in which one or more components are expanded. For example, a stent that self-expands and / or is under the influence of a radially outward force can "expand," as that term is used herein. A device that unfolds or unfolds can also assume a larger profile and can be considered to expand, as that term is used herein.

[0122]

[0200] The impellers may likewise be adapted and configured to expand in various ways depending on their structure. For example, one or more impellers may expand to different, larger sizes upon release from the sheath due to the materials and / or structure of the impeller 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 for all purposes.) Thus, retraction of the external restraint may, in some embodiments, allow both the expandable member and the impeller to naturally return to a larger profile, deployed configuration without any further actuation.

[0123]

[0201] As shown in the example in FIG. 4 , the pump portion includes first and second impellers spaced apart on either side of the aortic valve, each disposed within a separate expandable member. This contrasts with some designs in which the working portion includes a single elongated expandable member. Rather than a single, generally tubular expandable member extending all the way across the valve, the working end 1104 includes a conduit 1112 extending between expandable members 1108 and 1110. The conduit is more flexible and deformable than the pump at the location of the impellers, which may allow for more deformation of the pump portion at the location of the aortic valve leaflets than would occur if the expandable member were to span the leaflets. Having a more flexible central region may also cause less damage to the valve leaflets after the pump portion is deployed within a subject.

[0124]

[0202] Additionally, forces from the valve leaflets against the central region of a single expandable member may be axially transferred to other regions of the expandable member, possibly causing undesirable deformation of the expandable member at one or more impeller locations. This may cause the outer expandable member to contact the impeller, unnecessarily interfering with the impeller's rotation. A design including separate expandable members around each impeller results in a high level of precision in positioning the impeller relative to the expandable member, especially when each expandable member and each impeller is supported at both ends (i.e., distal and proximal). Two separate expandable members may be able to more reliably retain their deployed configuration compared to a single expandable member.

[0125]

[0203] As described herein above, it may be desirable to be able to reconfigure the working portion so that it can be delivered within a 9F sheath and still obtain a sufficiently high flow rate during use, which is not possible with some products currently under development and / or testing. For example, some products are too large to be reconfigured to a sufficiently small delivery profile, while some smaller designs may not be able to achieve the desired high flow rate. An illustrative advantage of the examples in FIGS. 1 , 2 , 3A-3D , and 4 is 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 portion can be reconfigured to a smaller delivery profile than designs using a single impeller to achieve the desired flow rate. Thus, these embodiments use multiple smaller, axially spaced, reconfigurable impellers to both achieve the desired smaller delivery profile and achieve the desired high flow rate.

[0126]

[0204] Thus, embodiments herein can achieve a smaller 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., for delicate valves). (alignment with the apex).

[0127]

[0205] Figure 5 illustrates a working portion similar to the working portion shown in Figure 1. Working portion 265 includes a proximal impeller 266, a distal impeller 267, both of which are coupled to a drive shaft 278 that extends into a distal bearing housing 272. At the proximal end of the working portion is a similar proximal bearing housing. The working portion also includes an expandable member, generally designated 270, and a conduit 268 secured to the expandable member and extending substantially the entire length of the expandable member. Expandable member 270 extends to a strut support 273 secured to a distal tip 273. The expandable member 265 includes a distal strut 271 located at and secured to the proximal strut support. The expandable member 270 also includes a proximal strut secured to the proximal strut support. All features similar to those shown in FIG. 1 are incorporated by reference into this embodiment for all purposes, even if not explicitly stated. The expandable member 265 also includes a helical extension member 269 disposed along the outer edge of the expandable member and has a helical configuration when the expandable member is in the expanded configuration as shown. The helical extension member 269 is arranged and adapted to induce rotational wrapping upon folding. The working portion 265 can be folded from the expanded configuration shown, while simultaneously rotating one or both impellers at a relatively slow speed to promote the rolled folding of the impellers due to interaction with the expandable member.

[0128]

[0206] There are alternative ways to construct pump sections so that extension causes rotation of the expandable member upon collapse (and thus causes the impeller blades to wrap and collapse). Any expandable member, even a dual-impeller design, can be constructed with this feature. For example, in an expandable member that includes multiple "cells," as that term is commonly known (e.g., laser-cut elongate members), the expandable member can have multiple specific cells that together define a specific configuration, such as a helical configuration, where the cells that define the configuration have different physical properties than other cells within the expandable member. In some embodiments, the expandable member can have a braided structure, and the twisted region can comprise an entire group of wires or a significant portion (e.g., more than half) of the braided wires. Such a twisted braided structure can be achieved during the braiding process, for example, by twisting the mandrel on which the wires are braided, as the mandrel is pulled along the length, particularly along the largest diameter portion of the braided structure. This construction may also be achieved during a second building operation, such as mechanically twisting the braided structure prior to heat setting the wound profile onto the shaped mandrel.

[0129]

[0207] Any of the conduits herein act, are configured, and are made of materials that create a fluid lumen between a first end (e.g., distal end) and a second end (e.g., proximal end). Fluid flows into the inflow region, through the fluid lumen, and then out from the outflow region. Flow into the inflow region may be labeled "I" herein, and flow out in the outflow region may be labeled "O." Any of the conduits herein may be impermeable. Any of the conduits herein may alternatively be semi-permeable. Any of the conduits herein may also be porous but still define a fluid lumen therethrough. In some embodiments, the conduit is a membrane or other relatively thin layered member. Any of the conduits herein may be secured to an expandable member, unless indicated to the contrary, such that the conduit may be radially inward and / or outward of the expandable member when secured. For example, the conduit may extend radially within the expandable member such that the inner surface of the conduit is radially within the expandable member when it is secured to the expandable member.

[0130]

[0208] 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 braided structure or it can be formed by laser machining. The material can be deformable, such as Nitinol. The expandable member can be self-expanding or adapted to be at least partially actively expanded.

[0131]

[0209] 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 by the action of a pull rod that moves at least one of the distal and proximal ends of the expandable member toward each other. In alternative embodiments, the deployment configuration can be influenced by the configuration of one or more expandable structures. In 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 mechanisms of deployment may be used.

[0132]

[0210] The blood pumps and fluid movement devices, systems, and methods herein may be used and positioned in a variety of locations within the body, and although specific examples may be provided herein, it should be understood that the working portions may be positioned in different body regions than those specifically described herein.

[0133]

[0211] In any of the embodiments herein in which a medical device includes multiple impellers, the device may be adapted to rotate the impellers at different speeds. FIG. 6A illustrates a medical device including a gear set 1340 coupled to both an inner drive member 1338 and an outer drive member 1336, which are in communication with a distal impeller 1334 and a proximal impeller 1332, respectively. The device also includes a motor 1342 that drives the rotation of the inner drive member 1338. The inner drive member 1338 extends through the outer drive member 1336. Starting the motor 1332 causes the two impellers to rotate at different speeds due to an underdrive or overdrive ratio. The gear set 1340 may be adapted to drive either the proximal or distal impeller faster than the other. Any of the devices herein may include any of the gear sets herein to drive the impellers at different speeds.

[0134]

[0212] Figure 6B illustrates a portion of an alternative embodiment of a dual impeller device (1350) in which the different impellers are similarly adapted to rotate at different speeds. A gear set 1356 is coupled to both an inner drive member 1351 and an outer drive member 1353, which are coupled to a distal impeller 1352 and a proximal impeller 1354, respectively. The device also includes a motor as in Figure 6A. Figures 6A and 6B illustrate how the gear sets can be adapted to drive the proximal impeller slower or faster than the distal impeller.

[0135]

[0213] 7 shows an alternative exemplary embodiment of a fluid pump 1370 capable of rotating the first and second impellers at different speeds. A first motor 1382 drives a cable 1376 coupled to the distal impeller 1372, while a second motor 1384 drives (via a gear set 1380) an outer drive member 1378 coupled to the proximal impeller 1374. The drive cable 1376 extends through the outer drive member 1378. The motors can be individually controlled and operated, and thus the speeds of the two impellers can be separately controlled. This system setup can be used with any system herein that includes multiple impellers.

[0136]

[0214] In some embodiments, a common drive cable or shaft can drive the rotation of two (or more) impellers, but the blade pitch (angle of rotational curvature) of the two impellers can be different, with the distal or proximal impeller having a steeper or gentler angle than the other impeller. This can have an effect similar to having a gear set. Figure 6C shows a portion of a medical device (1360) including a common drive cable 1366 coupled to a proximal impeller 1364 and a distal impeller 1362, as well as to a motor (not shown). The proximal impeller herein may have a larger or smaller pitch than the distal impeller herein. Any of the working portions (or distal portions) herein having multiple impellers can be modified to include first and second impellers with different pitches.

[0137]

[0215] In any of the embodiments herein, the pump section may be compliant (i.e., flexible) or semi-compliant (generally collectively referred to as "compact"). In various embodiments, the compliant portion may have an outer structure (referred to as a "compliant") that 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 on the valve leaflets is reduced. This can help prevent damage to the valve where the pump stretches over it.

[0138]

[0216] FIG. 8 illustrates an exemplary embodiment of a pump portion including first, second, and third axially spaced impellers 152, each disposed within an expandable member 154. A conduit 155 may extend along the length of the pump portion, as described in various embodiments herein, thereby helping to create and define a fluid lumen. However, in alternative embodiments, the first, second, and third impellers may be disposed within a single expandable member, similar to that shown in FIG. 1. In FIG. 8, the fluid lumen extends from the distal end to the proximal end, a feature described elsewhere herein. The embodiment in FIG. 8 may include any other suitable features, including methods of use, described herein.

[0139]

[0217] 8 is also an example of an outer housing having at least one bend formed between the proximal impeller distal end and the distal impeller proximal end such that the distal region of the housing distal to the bend is not axially aligned along the axis with the proximal region of the housing proximal to the bend. In this embodiment, there are two bends 150 and 151 formed in the housing, each between two adjacent impellers.

[0140]

[0218] In use, the bend formed in the housing can be positioned to span a valve, such as the aortic valve shown in Figure 8. In such an arrangement, the middle and distal-most impellers are positioned in the left ventricle and the proximal-most impeller is positioned in the ascending aorta. Bend 151 is positioned just downstream of the aortic valve.

[0141]

[0219] Bends, such as bends 150 or 151, may be incorporated into any of the embodiments or designs herein. The bends may be pre-formed angles or may be adjusted in situ.

[0142]

[0220] In any of the embodiments herein, unless indicated to the contrary, the outer housing may have a substantially uniform diameter along its length.

[0221] In Figure 8, the pump is positioned via the axillary artery, which is an exemplary method of accessing the aortic valve, allowing the patient to walk and be active less frequently. Any of the devices herein may be positioned via the axillary artery. However, it should be understood from the description herein that the pump may be introduced and tracked into position in various ways, including a femoral approach via the aortic arch.

[0143]

[0222] One aspect of the present disclosure is an intravascular blood pump including a distal impeller axially spaced from a proximal impeller. In one embodiment, the distal and proximal impellers are separated from one another. For example, the distal and proximal impellers may be connected only by their respective attachment to a common drive shaft. This differs from impellers having multiple blade rows. The term distal impeller, as used herein, does not necessarily refer to the most distal impeller of the pump, but may generally refer to an impeller positioned further distally than the proximal impeller, even if there are additional impellers disposed further distally than the distal impeller. Similarly, the term proximal impeller, as used herein, does not necessarily refer to the most proximal impeller of the pump, but may generally refer to an impeller positioned further proximally than the proximal impeller, even if there are additional impellers disposed further distally than the proximal impeller. If an impeller is present, it may refer to an impeller positioned further proximally than the proximal impeller. Axial spacing (or any derivative thereof) refers to the spacing along the length of the pump section, e.g., along the longitudinal axis of the pump section, even if bends are present in the pump section. In various embodiments, each of the proximal and distal impellers is positioned within a respective housing and configured to maintain a precise and constant tip clearance, and the span between the impellers has a relatively more flexible (or completely flexible) fluid lumen. For example, each of the impellers may be positioned within a respective housing having a relatively stiff outer wall to resist radial folding. The area between the impellers may be relatively stiff, and in some embodiments, this area is primarily held open by fluid pressure therein.

[0144]

[0223] Although not required in the embodiments herein, it may be advantageous to have minimal axial spacing between the proximal and distal impellers. For example, the pump portion may be delivered to a target site through a portion of anatomy with a relatively narrow bend, such as the aorta, and down into the aortic valve. For example, the pump portion may be delivered to the aortic valve through femoral artery access. It may be advantageous to have a system that is easier to bend, so that it is easier to deliver the system through bends in the anatomy. Some designs in which multiple impellers are fairly close to each other may make the system relatively stiff along the entire length spanning the multiple impellers. Spacing the impellers axially apart, and optionally providing relatively flexible regions between the impellers, can create portions of the system that are more flexible, easier to bend, and can be more easily and safely advanced through bends. An additional exemplary advantage is that axial spacing may allow for relatively more compliant regions between the impellers, which may be positioned, for example, at the location of a valve (e.g., the aortic valve). Furthermore, there are other potential advantages and functional differences between various embodiments herein and typical multi-stage pumps. A typical multi-stage pump includes rows of blades (sometimes referred to as impellers) that are closely functionally spaced, so that the rows of blades act together as synchronized stages. It should be understood that the flow may separate as it passes through the distal impeller. In various embodiments as described herein, the distal and proximal impellers may be spaced far enough apart so that flow separation from the distal impeller is substantially reduced (i.e., increased flow reattachment) and localized turbulence is dissipated before the flow enters the proximal impeller.

[0145]

[0224] In any of the embodiments, or in any portion of the description herein that includes a distal impeller and a proximal impeller, the axial spacing between the distal end of the proximal impeller and the proximal end of the distal impeller may be 1.5 cm to 25 cm (inclusive) along the longitudinal axis of the pump portion or along the longitudinal axis of the housing portion that includes the fluid lumen. This distance may be measured when the pump portion, including any impeller, is in an expanded configuration. This exemplary range may provide the exemplary flexibility benefits described herein when the pump portion is delivered through curved portions of anatomy, such as through the aorta and past the aortic valve. Figure 9 (shown outside the patient in the expanded configuration) illustrates the axial spacing between the impellers, and also illustrates the length Lc, which in some embodiments may be 1.5 cm to 25 cm as specified herein. In embodiments where there may be more than two impellers, any two adjacent impellers (i.e., impellers that do not have any other rotating impellers between them) may be axially separated by any of the axial separation distances described herein.

[0146]

[0225] Some embodiments include a proximal impeller distal end that is axially spaced along the axis from the distal impeller proximal end by 1.5 cm to 25 cm, and the disclosure herein also includes any axial spacing that is a subrange within that overall range of 1.5 cm to 25 cm. That is, the disclosure includes all ranges within that range having any lower limit from 1.5 or greater, and all subranges having any upper limit from 25 cm or less. The following examples provide illustrative subranges. In some embodiments, the distal end of the proximal impeller is axially spaced 1.5 cm to 20 cm, 1.5 cm to 15 cm, 1.5 cm to 10 cm, 1.5 cm to 7.5 cm, 1.5 cm to 6 cm, 1.5 cm to 4.5 cm, or 1.5 cm to 3 cm from the proximal end of the distal impeller along the axis. In some embodiments, the axial spacing is 2 cm to 20 cm, 2 cm to 15 cm, 2 cm to 12 cm, 2 cm to 10 cm, 2 cm to 7.5 cm, 2 cm to 6 cm, 2 cm to 4.5 cm, or 2 cm to 3 cm. In some embodiments, the axial spacing is 2.5 cm to 15 cm, 2.5 cm to 12.5 cm, 2.5 cm to 10 cm, 2.5 cm to 7.5 cm, or 2.5 cm to 5 cm (e.g., 3 cm). In some embodiments, the axial spacing is 3 cm to 20 cm, 3 cm to 15 cm, 3 cm to 10 cm, 3 cm to 7.5 cm, 3 cm to 6 cm, or 3 cm to 4.5 cm. In some embodiments, the axial spacing is 4 cm to 20 cm, 4 cm to 15 cm, 4 cm to 10 cm, 4 cm to 7.5 cm, 4 cm to 6 cm, or 4 cm to 4.5 cm. In some embodiments, the axial spacing is 5 cm to 20 cm, 5 cm to 15 cm, 5 cm to 10 cm, 5 cm to 7.5 cm, or 5 cm to 6 cm. In some embodiments, the axial spacing is 6 cm to 20 cm, 6 cm to 15 cm, 6 cm to 10 cm, or 6 cm to 7.5 cm. In some embodiments, the axial spacing is 7 cm to 20 cm, 7 cm to 15 cm, or 7 cm to 10 cm. In some embodiments, the axial spacing is between 8 cm and 20 cm, between 8 cm and 15 cm, or between 8 cm and 10 cm. In some embodiments, the axial spacing is between 9 cm and 20 cm, between 9 cm and 15 cm, or between 9 cm and 10 cm. In various embodiments, the fluid lumens between the impellers are relatively unsupported.

[0147]

[0226] In any of the embodiments herein, one or more impellers may have a length, as measured axially between the impeller distal end and the impeller proximal end (represented as "L" and "L" respectively in FIG. 9), of 5 cm to 10 cm, or any subrange thereof. SD " and "L SP"). The following examples provide illustrative subranges. In some embodiments, the impeller axial length is 0.5 cm to 7.5 cm, 0.5 cm to 5 cm, 0.5 cm to 4 cm, 0.5 cm to 3 cm, 0.5 cm to 2 cm, or 0.5 cm to 1.5 cm. In some embodiments, the impeller axial length is 0.8 cm to 7.5 cm, 0.8 cm to 5 cm, 0.8 cm to 4 cm, 0.8 cm to 3 cm, 0.8 cm to 2 cm, or 0.8 cm to 1.5 cm. In some embodiments, the impeller axial length is 1 cm to 7.5 cm, 1 cm to 5 cm, 1 cm to 4 cm, 1 cm to 3 cm, 1 cm to 2 cm, or 1 cm to 1.5 cm. In some embodiments, the impeller axial length is 1.2 cm to 7.5 cm, 1.2 cm to 5 cm, 1.2 cm to 4 cm, 1.2 cm to 3 cm, 1.2 cm to 2 cm, or 1.2 cm to 1.5 cm. In some embodiments, the impeller axial length is 1.5 cm to 7.5 cm, 1.5 cm to 5 cm, 1.5 cm to 4 cm, 1.5 cm to 3 cm, or 1.5 cm to 2 cm. In some embodiments, the impeller axial length is 2 cm to 7.5 cm, 2 cm to 5 cm, 2 cm to 4 cm, or 2 cm to 3 cm. In some embodiments, the impeller axial length is 3 cm to 7.5 cm, 3 cm to 5 cm, or 3 cm to 4 cm. In some embodiments, the impeller axial length is 4 cm to 7.5 cm, or 4 cm to 5 cm.

[0148]

[0227] In any of the embodiments herein, the fluid lumen can have a length from the distal end to the proximal end, shown as length Lp in FIG. 9. In some embodiments, the fluid lumen length Lp is between 4 cm and 40 cm, or any subrange thereof. For example, in some embodiments, the length Lp can be between 4 cm and 30 cm, between 4 cm and 20 cm, between 4 cm and 18 cm, between 4 cm and 16 cm, between 4 cm and 14 cm, between 4 cm and 12 cm, between 4 cm and 10 cm, between 4 cm and 8 cm, or between 4 cm and 6 cm.

[0149]

[0228] In any of the embodiments herein, the housing may be sized as shown in FIG. The tube may have an expanded diameter, at least at the impellers (and optionally at locations between the impellers), designated as Dp. In some embodiments, Dp may be 0.3 cm to 1.5 cm, or any subrange thereof. For example, Dp may be 0.4 cm to 1.4 cm, 0.4 cm to 1.2 cm, 0.4 cm to 1.0 cm, 0.4 cm to 0.8 cm, or 0.4 cm to 0.6 cm. In some embodiments, Dp may be 0.5 cm to 1.4 cm, 0.5 cm to 1.2 cm, 0.5 cm to 1.0 cm, 0.5 cm to 0.8 cm, or 0.5 cm to 0.6 cm. In some embodiments, Dp may be 0.6 cm to 1.4 cm, 0.6 cm to 1.2 cm, 0.6 cm to 1.0 cm, or 0.6 cm to 0.8 cm. In some embodiments, Dp can be between 0.7 cm and 1.4 cm, between 0.7 cm and 1.2 cm, between 0.7 cm and 1.0 cm, or between 0.7 cm and 0.8 cm.

[0150]

[0229] In any of the embodiments herein, the impeller may have a deployed diameter, shown in Figure 9 as dimension Di. In some embodiments, Di may be between 1 mm and 30 mm, or any subrange thereof. For example, in some embodiments, Di may be between 1 mm and 15 mm, between 2 mm and 12 mm, between 2.5 mm and 10 mm, or between 3 mm and 8 mm.

[0151]

[0230] In any of the embodiments herein, a tip clearance extends between the impeller outer diameter and the fluid lumen inner diameter. In some embodiments, the tip clearance can be between 0.01 mm and 1 mm, such as between 0.05 mm and 0.8 mm, or between 0.1 mm and 0.5 mm.

[0152]

[0231] In any of the embodiments herein, at least one of the flow diffuser(s) and stator(s) is located along the catheter shaft between two or more impellers, any one of which can increase fluid pressure between the impellers, reduce fluid vortices, and / or collectively increase the efficiency of the multiple impellers.

[0153]

[0232] In any of the embodiments herein, features at the fluid outlet of the expandable shroud basket or expandable member are shaped to act as flow diffusers, such as stent-like struts at the attachment between the catheter shaft outer dimension and the expandable member outer dimension, which may be blade-shaped with a twist oriented to redirect blood flow. In any of the embodiments herein, one or more portions of the catheter shaft downstream of the impeller may expand to a larger diameter to change the angle of blood flow and cause the blood flow to slow to a velocity closer to native aortic blood flow. Exemplary locations for the larger diameter downstream of the impeller may be at or near the area where the expandable shroud basket attaches to the catheter shaft and / or at the bearing housing adjacent to the impeller or on or adjacent to the internal motor.

[0154]

[0233] In some embodiments, the pump section may include one or more central members axially disposed between the proximal and distal impellers. The one or more central members may or may not be directly coupled to one another. The one or more central members may provide one or more of the following exemplary functions: structural support, flow modification, and maintaining impeller alignment. When the one or more central members provide structural support, the one or more central members may provide structural support to the outer conduit (which may be referred to herein as a "housing") and / or the one or more impellers. For example, they may help maintain tip clearance in the one or more impellers. In the description that follows, the one or more central members will be referred to as being in rotational operation with the impellers unless indicated to the contrary. As used herein, the term "central member" or any derivative thereof does not imply that the member is located at least midway between the two impellers, but merely that the central member is somewhere axially between the two impellers. "Central member" may therefore be used synonymously with the term "intermediate member" within this specification.

[0155]

[0234] FIG. 10 is a side view illustrating an exemplary pump portion 20 of fluid-pumping device 10. The distal direction is indicated by "D" and the proximal direction is indicated by "P." Pump portion 20 (and other pump portions herein) may also be referred to herein as the distal portion. Pump portion 20 includes a fluid flow conduit as described herein, as well as an expandable member 30. Pump portion 20 also includes a support structure 33 (which may be referred to herein as a scaffold), which in this embodiment is a stent-like member, but may be constructed using any of the examples provided herein. The conduit includes a membrane 34 having a distal end 31 and a proximal end 32. Membrane 34 is coupled to support structure 33. Membrane 34 at least partially creates and defines an internal lumen through which fluid flows when impellers 40 and 50 are actuated. Membrane 34 may have any of the characteristics of any of the conduits described herein. When the support structure 33 expands to the deployed and expanded configuration shown in Figure 10, the conduit also assumes the open configuration shown in Figure 10. Fluid flow is shown generally in the direction of the "F" arrow when the impellers 40 and 50 are actuated. The impellers 40 and 50 may be any of the impellers described herein and may have any of the characteristics described herein.

[0156]

[0235] In this embodiment, pump portion 20 includes a central member 60 axially disposed between distal impeller 40 and proximal impeller 50. In this embodiment, central member 60 functions as at least a flow control member to modify or control the flow of blood within the fluid lumen. FIGS. 11A, 11B, and 11C show perspective, side, and distal end views of central member 60, with the other pump components of the distal portion removed for clarity. Central member 60 includes a hub 67 and a plurality of blades extending therefrom; in this embodiment, three (i.e., blades 63, 64, and 65), although more or fewer blades may be used. Central member 60 has a distal or leading region 61 and a trailing or proximal region 62. The blades in distal region 61 are configured to recover pressure from distal impeller 40, and the blades in proximal region 62 are configured to direct flow toward proximal impeller 50. The blades in the distal region 61 have a higher degree of curvature relative to the hub than do the blades in the proximal region 62. The degree of curvature generally decreases from the distal end to the proximal end. This creates a transition from the distal region acting more as a diffuser to the proximal end acting more as a stator or guide vane. The proximal region 62 provides the stator functionality in this embodiment.

[0157]

[0236] In addition to controlling flow and creating a particular type of flow along its length, central member 60 also provides structural support to the conduit. Member 60 provides stability in the region axially between impellers 40 and 50. The central region between the impellers can experience various forces thereon, and member 60 can strengthen the central region in response to those forces. For example, distal region 20 can be positioned within the heart, and in particular, the central region between the impellers can be positioned across a heart valve (e.g., the aortic valve) where much movement occurs as the valve opens and closes. Forces from the valve commissures can exert a radially inward force on expandable member 30, and member 60 can support at least some portion (including substantially the entire central span) of expandable member 30. ) and keep the lumen open. Additionally, for example, member 60 can also reduce vibrations between the impellers that occur as the impellers rotate. The structural support provided in the central region can help maintain a gap between the tips of the impellers and expandable member 30. Central member 60 is adapted and configured to be collapsed into a delivery configuration. 10 (like the impellers), central member 60 engages expandable member 30 and provides structural support from within the lumen. In an alternative embodiment, central member 60 may be permanently attached to the expandable member so that they fold and expand together. In this embodiment, central member 60 is therefore adapted and configured to both control and create specific flow along its length between the impellers, as well as to provide structural support to the expandable member.

[0158]

[0237] An optional central member (e.g., control member 60) may extend axially for substantially the entire mid-span ("CS") between the impellers. The length of the mid-span "CS" is shown in FIG. 10. As discussed above, there is structural support that is advantageous in having a structural support member (e.g., member 60) disposed directly adjacent to the impellers, as is the case for both impellers in the embodiment in FIG. 10. When it is desirable to have a single central member extending from the distal end to the proximal end (as in the embodiment in FIG. 10), the central member may extend at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the mid-span distance between the impellers. It is desirable to have a gap between the impeller and the control member, which prevents friction from contacting the rotating impeller and the control member.

[0159]

[0238] In other embodiments herein, the intermediate member may not extend along a significant portion of the length between the impellers (see, for example, intermediate members 92 and 102 in FIG. 12A ). In any of the embodiments herein, the central member may extend 5% or less, or 10% or less, or 15% or less, or 20% or less, or 25% or less, or 30% or less, or 35% or less, or 40% or less, or 45% or less, or 50% or less, or 55% or less, or 60% or less, or 65% or less, or 70% or less, or 75% or less, or 80% or less, or 85% or less, or 90% or less, or 95% or less, or 99% or less of the mid-span between the first and second impellers.

[0160]

[0239] In any of the embodiments herein that include multiple impellers, the axial spacing between the impellers (along the length of the pump section, even if there are bends in the pump section) can be from 2 mm to 100 mm, or any combination of upper and lower limits inclusive of 5 and 100 mm (e.g., 10 mm to 80 mm, 15 mm to 70 mm, 20 mm to 50 mm, 2 mm to 45 mm, etc.).

[0161]

[0240] The length of the central member or members can be any desired length between the first impeller and the second impeller.

[0241] In some embodiments, at least 50% of the length of the central member provides functionality that can be considered a stator rather than a diffuser. For example, in the embodiment in FIG. 10, the proximal half of central member 60 functions as a stator rather than a diffuser. The diffuser section may be long enough to recover at least 5-50% of the pressure from the kinetic energy created by the previous stage (e.g., the distal impeller). The stator section may be long enough to direct flow to the next stage (e.g., the proximal impeller) without excessive frictional losses.

[0162]

[0242] Although the embodiments in Figures 10-11C illustrate a single central member 60 between the impellers, in some alternative embodiments, the distal or working portion may include two or more separate, axially spaced central members disposed between the impellers. Figures 12A-13C illustrate such exemplary designs.

[0163]

[0243] 12A is a perspective view of an exemplary distal portion 80 of a pumping device 70. The embodiment in FIGS. 12A-13C is similar in some respects to the dual impeller design shown herein (e.g., FIG. 3A) with multiple expandable members. One difference between the proximal expandable member 100 and the distal expandable member 80 is that the distal portion 80 includes a distal central member 92 and a proximal central member 102, each of which is disposed closely adjacent to one of the impellers. At least a portion of the central member 92 is axially disposed within an end of a structural support 91 (e.g., a stent-like device) that is part of the distal expandable member 90. The central member 92 is also radially disposed within the structural support 91. At least a portion of the central member 102 is axially disposed within an end of a structural support 101 (e.g., a stent-like device) that is part of the proximal expandable member 100. The central member 102 is also radially disposed within the structural support 101. A conduit 95 (which may have any of the conduit characteristics described herein) extends from the distal end to the proximal end, including extending axially between the central member 92 and the central member 102.

[0164]

[0244] 13A, 13B, and 13C show end perspective, perspective, and side views of central members 92 and 102 (other components are not shown for clarity). The central members include an outer annular member 110 and an inner annular member 113 with a plurality of blades 112 extending therebetween.

[0165]

[0245] Similar to the central member 60 in FIG. 10 , the central members 92 and 102 are adapted and configured to provide fluid control and structural support. The central members 92 and 102 are disposed radially within the expandable members 90 and 100 and at least partially axially within the expandable members 90 and 100, respectively. The annular member 110 and the radially extending blades 112 provide radial reinforcement and support, thus helping to keep the lumen open, maintain tip clearance, and reduce vibration between the impellers. In this embodiment, the blades are also configured so that the central members 92 and 102 act as stators. For example, the proximal central member 102 can direct flow before it reaches the proximal impeller. The distal central member 92 can also help restore pressure. As used herein, "directing flow" and its derivatives may include changing the ratio of axial to radial flow components. For example, any stator functionality herein (and any component that makes the stator functional) may increase the axial flow component and decrease the radial flow component.

[0166]

[0246] In this embodiment, a portion of the central span between the impellers does not include an expandable member or support member, but does include a conduit 95 (e.g., a flexible membrane). This is similar to the embodiment in FIG. 3A. The deformable conduit 95 may allow the central region to deform to some extent up to where the leaflets coapt. However, the support members 92 and 102 help to stiffen the ends of the expandable members 90 and 100, even though the conduit 95 is allowed to deform in more of the central region.

[0167]

[0247] A further difference between the embodiment in Figure 3A and Figures 12A-13C is that in Figures 12A-13C, the expandable members do not have struts on the inner portion of the expandable member (closer to the middle along the longitudinal axis). Central members 92 and 102 replace those struts.

[0168]

[0248] Central members 92 and 102 are foldable and expandable, just like the impellers herein. Central members 92 and 102 are secured to components that pass through lumen 114 (see FIG. 13B) and are secured so that they do not rotate when the impellers rotate. A rotatable shaft passes through central members 92 and 102. Central members 92 and 102 are directly adjacent to the impellers but are spaced apart enough to prevent any friction between the parts.

[0169]

[0249] In other embodiments, there are three or more central members axially spaced between the impellers. For example, one or more separate central members may be disposed between central members 92 and 102 and may be secured, for example, to the same elongated shaft to which central members 92 and 102 are secured.

[0170]

[0250] Central members 92 and 102 may be permanently attached to expandable members 90 and 100, respectively, so that they expand and collapse together. For example, the radially outer surface of annular section 110 may be secured to the expandable members. Alternatively, central members 92 and 102 are not attached to the expandable members, but are sized to contact / engage the expandable members when both are in their deployed configurations.

[0171]

[0251] An axle operably connected to the impeller may extend through the shaft to which central members 92 and 102 are fixed, such that the axle can rotate within the non-rotating elongated shaft to drive rotation of the impeller without causing rotation of the central member.

[0172]

[0252] In some alternative embodiments not shown, aspects of central members 92 and 102 may be combined into a single central member design. For example, annular outer region 110, from which blades 112 extend, may also be combined along all or some portion of the length of a single central member. For example, in some alternative embodiments to FIG. 10 , central member 60 may include one or more annular outer regions anywhere along its length. For example, central member 60 may include a single outer annular region extending along its length, with blades 63, 64, and 65 extending from the single outer annular region. Or, for example, central member 60 may include multiple annular outer regions disposed anywhere along its length. For example, the distal and proximal end regions of central member 60 may each include separate annular outer regions from which blades 63, 64, and 65 extend. The separate annular outer regions may be of any desired length and occupy any desired percentage of the shaft spanning between the impellers. Or, for example, the central member may also include a third separate annular outer region in the center of central member 60. Additional separate outer annular regions may be spaced axially along the length of central member 60 (or any other single central member).

[0173]

[0253] In some alternative embodiments not shown, aspects of central member 60 can be incorporated into designs including multiple central members (e.g., central members 92 and 102). For example, blades 112 (shown in FIGS. 13A and 13B) within central members 92 and 102 need not have a straight configuration but can be curved to some extent, like the portions of blades 63, 64, and 65 shown in FIG. 10. Or, some portions of blades 112 can be straight and some portions can be curved, such as blades 63-65 in FIG. 10. For example, distal central member 92 can have blades with curved portions, while proximal central member 102 can have straight blades. In these designs, central member 92 can act more like a pressure restorer, while proximal central member 102 can function more like a stator to direct flow.

[0174]

[0254] Additionally, the distal central member 92 need not have the same configuration as the proximal central member 102 .

[0255] Additionally, in other embodiments, aspects of distal regions 20 and 80 in Figures 10 and 12A may be incorporated with other distal regions. For example, in Figure 10, support structure 33 extends across the entire central span between the impellers. In distal region 80 shown in Figure 12A, the support structure may similarly extend across the span between central members 92 and 102. For example, distal support structure 91 may extend proximally into the central span and also form proximal support structure 101.

[0175]

[0256] The fluid pump described with respect to Figures 10-13C can be positioned at any of the anatomical locations described herein. In an exemplary method of use, the fluid pump can be used in a method of positioning the device during use as shown in Figure 4. The entire description herein relating to Figure 4 is incorporated by reference for all purposes with respect to the embodiment in Figures 10-13C. For example, fluid pump 10 can be placed across the aortic valve, such that the distal impeller is positioned in the left ventricle and the proximal impeller is positioned in the ascending aorta. In this position, a central region of the distal portion, including a portion of control member 60, is positioned at the aortic valve.

[0176]

[0257] Any of the pump sections herein that include multiple impellers may also include more than two impellers, such as three, four, five impellers (for example).

[0258] While some of the above embodiments describe pump portions or components that are collapsible and expandable (or at least movable between collapsed and expanded configurations), in any of those embodiments, the components and expandable outer housing may also be non-expandable and non-collapsible. That is, any of the components in those embodiments may be present, but this component may be a non-expandable variant of those components. For example, the impeller above may be non-expandable rather than expandable.

[0177]

[0259] 14A and 14B show side views of the distal portion of an exemplary embodiment of a blood pump in which the components are not expandable and collapsible. All components in this embodiment may be rigid, fixed parts.

[0178]

[0260] Figure 14B illustrates internal components not visible in Figure 14A. The descriptions in Figures 14A and 14B are illustrative and not limiting. The pump portion shown in Figures 14A and 14B includes a stage 1 section and a stage 2 section spaced axially along the length of the pump portion. In this embodiment, the central section between the two stages (generally labeled the "flexible section") has a bend formed therein, which may extend along any portion of the central section between the stages, such as at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%. The bends can be fabricated into the central region so that the bends reside outside the body, but the central region can be sufficiently flexible so that it can be reconfigured into a straight delivery configuration within a delivery device such as a delivery sheath or introducer.

[0179]

[0261] The pump section includes multiple axially aligned inlet apertures distal to the stage 1 component. While two inlet apertures are shown in FIGS. 14A and 14B, there may be three or more inlet apertures. There are also two outlet apertures axially aligned with a portion of the stage 2 rotor. The inlet and outlet apertures extend through the radially outer wall of the pump section. Distal is the right side in the figures, and proximal is the left side in the figures. In various embodiments, the pump section includes a set of inlet apertures distal to the stage 1 component and a set of outlet apertures proximal to the stage 2 component. In various embodiments, the pump section includes a set of inlet apertures distal to the distal pump and a set of outlet apertures proximal to the proximal pump. In various embodiments, there are no apertures (for inlet or outlet) between the stage 1 component and the stage 2 component. In various embodiments, there are no apertures (for inlet or outlet) between the distal pump impeller and the proximal pump impeller.

[0180]

[0262] Stage 1 in this embodiment includes a distal impeller (labeled rotor), inlet guide vanes distal to the rotor, and outlet guide vanes proximal to the distal rotor. A vane (and any vane herein) is generally considered a flow-modifying element or derivative thereof as that term is used herein. Either the vane or rotor may include a hub and extending blades as shown, or may include other known impeller and stator / vane designs. The vane (and any flow-modifying component herein) is positioned closely next to the distal impeller, less than 10 mm (along the length of the device), or less than 9 mm, or less than 8 mm, or less than 7 mm, or less than 6 mm, or less than 5 mm, or less than 4 mm, or less than 3 mm, or less than 2 mm, or less than 1 mm, etc. "Closely" as used herein can include any of these axial distances. "Closely adjacent," as used herein, may also refer to a distance of less than twice the diameter of the central lumen.

[0181]

[0263] Stage 2 in this embodiment includes a proximal impeller (rotor) and inlet guide vanes distal to the proximal impeller. All of the above disclosure relating to the vanes in Stage 1 are and can be incorporated into the Stage 2 vanes.

[0182]

[0264] In this example, the stage 1 (distal) rotor is configured as an axial flow impeller and the proximal impeller (stage 2) is configured as a mixed (diagonal) flow impeller, but these are illustrative and other impeller designs can be used for either impeller.

[0183]

[0265] The pump portion in this embodiment includes a flexible outer housing between the stages. The flexible outer housing can be, for example, a flexible polymeric material formed with a slight degree of curvature, can be straightened for delivery, and is connected to the distal and proximal stage sections. In some embodiments, the flexible central section can be an ultra-thin-walled, stiff material that provides some flexibility. In other embodiments, for example, the flexible section can include multiple elongated support members (e.g., nitinol wire) to which a flexible membrane is attached. The elongated support members can be formed with bends therein and spaced around the outer edge of the flexible section, thereby forming a lumen through which the flexible membrane passes. In some embodiments, the flexible section may comprise a laser-cut tube (e.g., a laser-cut polymeric or metallic material, such as Nitinol) with one or more slots cut in at least one section to impart flexibility (e.g., creating a spine along one side with ribs extending around at least a portion of the outer edge, the ribs being formed by cutting the material), and a membrane-like material may be attached to the slotted tubular member to cover the removed material. Flexible materials may also include stent-like devices configured with bends and membrane-like material covering the stent apertures.

[0184]

[0266] As used herein, "axially spaced" includes embodiments in which a bend is present in the outer profile (e.g., FIGS. 14A and 14B), and a bend may be included in any of the embodiments herein. Axially spaced, when the phrase is used elsewhere herein, is intended to refer to spacing along the device, even if a bend is present in the outer profile of the pump portion (e.g., FIGS. 14A and 14B). It may refer, for example, to spacing along the longitudinal axis of the pump portion.

[0185]

[0267] In alternative embodiments to those shown in Figures 14A and 14B, not all of the components shown need to be included, for example, some of the wings may not be present depending on the flow required.

[0186]

[0268] Any other disclosures herein relating to any aspect of the pump device or method of use (e.g., external motor, arrangement when used) are incorporated by reference into the embodiments in Figures 14A and 14B.

[0187]

[0269] The illustration shown in Figure 14A illustrates an exemplary placement of the device, showing the surrounding / surrounding anatomy: the distal impeller is positioned within the left ventricle, while the proximal impeller is positioned within the ascending aorta, and the impellers can be spaced accordingly.

[0188]

[0270] A blood pump, such as any of the intravascular pumps herein, may benefit from having one or more fluid paths through which fluid can flow through the device. For example, without limitation, a blood pump may benefit from having one or more fluid paths through which fluid can flow to perform any of these exemplary functions: cooling rotating components (e.g., drive cables) to prevent them from overheating, flushing away small particulates that may disrupt the rotating components (e.g., drive cables) to prevent them from being damaged by small particulates, lubricating rotating components (e.g., one or more bearings), and preventing blood from entering the pump (e.g., near or at the distal end of the pump). Fluid delivery through one or more flow paths may provide any number of these functions.

[0189]

[0271] 15A-15D illustrate an exemplary embodiment of a fluid delivery system incorporated into an exemplary fluid pump (e.g., a blood pump) having fluid inlet and outlet ports. Figure 15A illustrates a portion of the device proximal to one or more impellers, which in this embodiment includes the proximal end of the catheter, the drive cable and motor assembly that causes rotation of the impeller, the fluid inlet and outlet ports, and a guidewire port that allows access to a guidewire passage or lumen.

[0190]

[0272] Figure 15B shows a region of the device distal to the region shown in Figure 15A, but includes some of the catheter components shown in Figure 15A. Figure 15C shows a region of the device distal to the region in Figure 15B, and Figure 15D shows a region of the device distal to what is visible in Figure 15C.

[0191]

[0273] 15A-15D illustrate different sections of an exemplary blood pumping device, it should be understood that in alternative embodiments, aspects of the system may vary. For example, in alternative embodiments, the portion of the device having the impeller may vary, may include only a single impeller, or the expandable housing around the impeller may have various configurations. It should be understood that individual regions of the device may themselves be incorporated into a variety of different types of blood pumps.

[0192]

[0274] One aspect of this exemplary embodiment includes a guidewire access port, which also functions as a fluid port, in this embodiment, a fluid exit port. Motor sealing cap 138 has guidewire channel 137 formed therein and includes a guidewire port on a radial side that provides access to channel 137 from outside the device. The motor sealing cap may be an optional component, and guidewire channel 137 may alternatively be formed in a different portion of the device (e.g., may not function as a motor sealing cap). The device also includes a drive cable coupler 135 having guidewire channel 136 formed therein, which is a portion of the guidewire passageway. Drive cable coupler 135 is rotated by the motor, causing rotation of drive cable 143, which in turn causes rotation of one or more impellers in the pump portion. Thus, these components are considered to be in rotational communication. Channel 137, including the guidewire port, is formed in the device, and the motor rotates 15A , channel 137 is aligned with channel 136, allowing a guidewire to be advanced or removed through channel 137 and advanced through channel 136. If a guidewire is inserted, the guidewire can be advanced further distally throughout the device and out the distal end, as described in more detail below. As also described in more detail below, the guidewire access port acts as a fluid exit port, allowing return fluid to flow from return region 139 out the exit port.

[0193]

[0275] One advantage of having the guidewire access port (portion of channel 137) where it is in this embodiment is that after the pump portion has already been advanced to a location within the patient, if necessary, the guidewire can be reinserted into the port and inserted all the way to the distal end and out. Importantly, the guidewire can be reinserted without having to remove much of the device from the patient, as with some rapid exchange designs, and without having to remove the motor assembly. Thus, this exemplary embodiment allows for easy re-entry of the guidewire without having to remove the motor assembly and without having to remove the device from the subject.

[0194]

[0276] The ability to reinsert a guidewire during use can be advantageous, for example, but not limited to, by allowing for repositioning of the pump portion if desired or necessary. For example, if the pump portion moves out of position relative to an anatomical landmark (e.g., the aortic valve), a guidewire may need to be inserted to safely reposition it relative to the anatomical landmark.

[0195]

[0277] Because the guidewire pathway extends through the rotating components (e.g., drive cable coupler 135), it is important that the guidewire is not present in the guidewire pathway when the rotating components are active. The devices herein may also include an automatic sensing mechanism to detect the presence of a guidewire in the guidewire pathway and / or a prevention mechanism that prevents the motor from being started if the guidewire is within the lumen. For example, without limitation, there may be a sensor that can selectively detect the presence of a guidewire in the guidewire pathway and communicate the same to a controller that prevents the motor from being started.

[0196]

[0278] In this embodiment, there is a single fluid inlet channel or lumen 131 through which fluid can be delivered into the device. FIG. 15B illustrates one region of the device and also illustrates different paths the fluid can take after being delivered into the device. After fluid is advanced into the fluid inlet port channel 131 (including the inlet port), it travels through the space 147 between the clean purge tube 141 and the drive cable tube 142. This is considered the clean input fluid. This path dead-ends at the distal catheter cap 149. The fluid passes through one or more apertures 146 formed in the distal region of the drive cable tube 142 as shown in FIG. 15B and into the annular space between the drive cable tube 142 and the drive cable 143. A portion of this fluid (optionally the majority of the fluid) returns proximally through this annular space, lubricating and cooling the drive cable 143 and flushing any potential particulates along its path. This return fluid continues to flow proximally and into region 139 shown in Figure 15A and out of the fluid port (which is also the guidewire access port) through channel 137. Thus, the fluid exit port also functions as a guidewire access port in this embodiment.

[0197]

[0279] While the majority of the fluid returns proximally to region 139, a portion of the fluid continues distally beyond the distal end of drive cable 143 after passing through aperture 146. A portion of the fluid follows proximal bearing pathway 160 through aligned bearing 162 to prevent blood ingress. Fluid flow along pathway 160 toward bearing 162 can be controlled, for example, by controlling the input flow pressure and restriction of the return fluid in the proximal region of the device.

[0198]

[0280] After passing through aperture 146, a portion of the fluid will flow through drive cable 143, along path 161, and will also continue distally through the device (e.g., through hypotube 144) and out the bore to lubricate any rotating surfaces and prevent blood ingress, as will be explained in more detail below. Guidewire lumen 145 is therefore positioned to also function as a distal bearing fluid flow path.

[0199]

[0281] Some fluid flows distally along pathway 161, as shown in FIG. 15C, and passes through holes along pathway 163 to lubricate one or more of bearing 162, thrust bearing 177, and alignment bearing 178. Some of the fluid continues distally through impeller 165 (the proximal impeller in this embodiment) in the direction of arrow 164 shown in FIG. 15C. Some of the fluid passes through apertures along pathway 167 to lubricate optional alignment bearing 172 that supports central member 171, which may be any of the foldable support members, including any of the central or intermediate members herein. Some of the fluid continues distally through the guidewire lumen in the direction of arrow 168 and through optional distal impeller 173. Some of the fluid passes through holes along pathway 169 to lubricate bearing 174, which is distal to the distal impeller. Some of the fluid can also flow through valve 175 and out the distal end of the device, helping to prevent blood ingress.

[0200]

[0282] In this exemplary embodiment, a single flow path through the tubular member (pathway 161 extending distally through the guidewire lumen shown in FIG. 15B) leads to (is in fluid communication with) at least three distally located bearing lubrication fluid paths 163, 167, and 169, which lubricate three axially spaced apart bearing regions. In some alternative embodiments, there may be a single lubricated bearing region, two lubricated bearing regions, or four or more lubricated bearing regions, depending on the number of structures disposed within the expandable housing that require bearings, and therefore lubrication.

[0201]

[0283] An exemplary method of using the device in FIGS. 15A-D includes inserting a guidewire near the target site (e.g., into the left ventricle via femoral artery access), then providing a distal guidewire port over the guidewire, and advancing the device over the guidewire toward the target site (e.g., the aortic valve). The method may also include removing the guidewire from the guidewire path and coupling the proximal portion shown in FIG. 15A to the fluid inlet and outlet couplers in the inlet and outlet fluid positions, respectively. The motor may be started to start one or more impellers. If the guidewire needs to be reinserted, the fluid output connector may be removed and the guidewire may be reinserted (e.g., for repositioning). The guidewire may then be removed, and the fluid outlet coupler may again be placed in fluid communication with the guidewire passage. These methods, or any of them, may be incorporated into the use of any of the suitable devices herein, such as the devices in FIGS. 16A and 16B. Additionally, any of the steps in any of the exemplary methods of use herein, such as those below, may be incorporated into the use of the blood pump in this embodiment.

[0202]

[0284] 16A and 16B are incorporated into an exemplary fluid pump (e.g., a blood pump) having a first fluid flow path with a first fluid inlet port and a first fluid outlet port. 16A illustrates an exemplary embodiment of a fluid delivery system. However, in this embodiment, there is also a second fluid flow path that is not in fluid communication with the first flow path. Device 180 in FIGS. 16A and 16B is similar to that shown in the embodiment in FIGS. 15A-D, except that in this embodiment, fluid path 161 from FIG. 15B does not originate as fluid flowing through the drive cable. In this embodiment, the fluid flow path including the guidewire lumen (see fluid path 196 in FIG. 16B) is in fluid communication with a separate and second fluid inlet port 189, similarly positioned to function as a guidewire access port, as shown in FIG. 16A. Drive cable 183 has a drive cable liner 187 on its inner surface to seal distal bearing flow path 196 (through which the guidewire lumen passes). In this embodiment, the guidewire access port does not function as a fluid outlet as in FIGS. 15A-D, but rather as a fluid inlet port and therefore still functions as a fluid port or fluid access.

[0203]

[0285] The blood pump also includes a first fluid pathway including an inlet port 181 and an outlet port 182 as shown in FIG. 16A. This flow path is very similar to the pathway in FIGS. 15A-D, except that it does not include a path through the drive cable and hypotube (i.e., it does not include a guidewire lumen). Fluid is advanced through the port inlet port 181 and flows distally along pathway 197 in FIG. 16B between the clean purge tube 185 and the drive cable tube 184. This pathway dead-ends at the distal catheter cap, similar to the embodiment in FIGS. 15A-D. Fluid flows through a lumen in the drive cable tube 184 and returns proximally in the annular space between the drive cable tube 184 and the drive cable 183. In this portion of the pathway, the fluid lubricates and cools the drive cable, flushing any potential particulates along its path and carrying them proximally to the fluid exit port 182 shown in FIG. 16A. Seal 200 seals and prevents fluid from passing proximally.

[0204]

[0286] Fluid flowing through the first fluid pathway thus lubricates and cools the drive cable, as well as flushes away potential particulates, and returns to exit port 182. Fluid flowing through the second fluid pathway continues further distally through the system, lubricating one or more distal bearings, similar to the embodiment in FIGS. 15A-D. For example, pathway 199 shown in FIG. 16B is the same as pathway 163 in FIG. 15C, lubricating bearings in that bearing region. While not shown, the fluid flow path distal to the view shown in FIG. 16B could be identical to that in FIG. 15D, thus lubricating additional bearings and, optionally, exiting through a valve at the distal end of the device. This second pathway can also therefore prevent blood ingress, which is described in more detail in FIGS. 15A-D.

[0205]

[0287] In any of the devices herein, the pump portion may include a distal end valve distal to the impeller to seal the distal guidewire port after the guidewire is removed, but allow the guidewire to be reinserted therethrough.

[0206]

[0288] 17A-17F illustrate an exemplary pump portion 201 of an exemplary blood pump. Pump portion 201 may be used interchangeably with any other aspect of any of the blood pumps herein. Pump portion 201 is also shown in the embodiment in FIGS. 15A-16B, and therefore, any feature or method of use described therein is incorporated by reference into this embodiment. Additionally, not all aspects of this embodiment need be included; instead, any suitable feature in pump portion 201 may be substituted for a different feature or method of use from a different preferred embodiment or portion of the present disclosure. For example, any impeller in pump portion 201 may be substituted for any suitable impeller from any other portion of the present disclosure. FIG. 17A is a side view, and FIG. 17B is a cross-sectional side view.

[0207]

[0289] The pump section 201 includes a drive shaft to which a distal impeller 203 and a proximal impeller 202 are fixed. The pump section includes a drive cable tubing 204. Rotation of the drive cable tubing 204, via rotation of a drive cable (not shown), causes rotation of the impeller. More or less than two impellers may be included in the pump section.

[0208]

[0290] The pump portion 201 also includes a collapsible housing 205 including a collapsible support structure 206 (which may also be referred to herein as a scaffold) having 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.

[0209]

[0291] Pump portion 201 includes an optional intermediate (which may be referred to herein as the center or between the impellers) member 209 between the two impellers, which may be any center member(s) herein.

[0210]

[0292] In any of the embodiments herein, the distal impeller may have a length that is smaller than the proximal impeller, such as that shown in the device in FIG. 17A.

[0293] FIG. 17C is a side view of the proximal portion of support structure 206 in an expanded configuration (other portions are not shown for clarity). FIG. 17D is a proximal end view of the support structure. The region shown generally surrounds impeller 202 in FIGS. 17A and B. Support structure 206 can be formed using a variety of techniques, such as laser cutting tubular starting material. Support structure 206 includes multiple arms (four in this embodiment) that transition from a larger diameter to a smaller diameter in region 218 in the proximal region. Each of the arms has a bend in region 219, and as shown, is vertical between the bend regions. The vertical region may help stabilize the transition region between the larger and smaller diameter regions, reducing, and preferably eliminating, its effect on the fluid at the outflow.

[0211]

[0294] In the larger diameter region of the support structure, the support structure 206 includes staggered apices 221 (only two are labeled) that alternate every other apices. Staggered in this context refers to the axial location of the apices' ends. Each of the four arms forms an apice that extends further proximally than the adjacent apices. The staggered apices can facilitate sheathing and offset fill volume during collapse of the pump portion. Apices, as used herein, can also be considered valleys depending on the orientation, just as convex and concave are relative terms.

[0212]

[0295] The support structure 206 also includes a plurality of hub features 220, each configured to stably adhere to components 222 (four in this embodiment) in the distal region of the scaffold landing zone 179 (see FIG. 17E). The hub features 220 can constrain axial movement along the bearing hub.

[0213]

[0296] The support structure 206 also includes axially spaced helical regions 213 (only some are labeled in FIGS. 17A and 17B ) that include multiple arms (or arm portions) having a helical configuration. In FIG. 17C , the helical regions 213 include helical arms 214 (only four 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; 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 may axially overlap one or more helical sections 213. The pitch of the helical arms may vary.

[0214]

[0297] FIG. 17F is a cross-sectional view of FIGS. 17A-E to further illustrate the scaffold pattern. The scaffold design is illustrated in a flattened plan view, with only some of the scaffold parts labeled for clarity.

[0215]

[0298] The axial length of one or more helical regions 213 may be less than the axial length of the impeller that it axially overlaps. For example, in Figure 17E, the helical regions 213 are each less than the entire length of the impeller. The axial length of the helical regions 213 is also less than the length of the distal impeller 203, even though a single helical region does not completely axially overlap the impeller.

[0216]

[0299] The configuration or shape of the multiple helical arms may generally follow the helical shape of the outermost region of the impeller (e.g., the outermost region of the helical blade) and be configured to facilitate sheathing to promote rotational sheathing and radial compression of the blade. In other words, the scaffold and any given blade may each have a strut pattern (and particularly a helical arm configuration) and a camber line (a section of which is labeled "CL" in FIG. 23 ) that can twist each component in a complementary manner to achieve one or more of: reducing sheathing forces, increasing packing efficiency, and reducing component strain when sheathing is applied and when the sheathing is removed. The camber line of the blade may generally follow the helical configuration of at least one of the helical arms within the helical region, as can be seen in FIG. 17E , where a section of the camber line CL of one blade is shown in FIG. 23 . In a side view of the pump portion (e.g., Figure 17E or Figure 23), and in some embodiments, the helical element and blade may overlap in one or more locations, and the tangent "T" of the helical element and blade camber line at the overlap location (see Figure 23) may form an angle of 45 degrees or less, 35 degrees or less, 20 degrees or less, 15 degrees or less, or 10 degrees or less.

[0217]

[0300] There can be any number of helical regions 213 spaced axially along the support structure. Adjacent helical regions need not be equally spaced along the entire length of the scaffold.

[0218]

[0301] In some exemplary methods of sheathing, the method may optionally include a folding process that includes rotational movement of the components to which the support structure is coupled, which rotational movement may be controlled by an actuator (e.g., a handle) disposed outside the patient.

[0219]

[0302] In some embodiments, the four proximal arms (generally labeled 218) may be inverted so that the bend in the larger diameter section is located further proximally than the bend in the smaller diameter section.

[0220]

[0303] The scaffold design in the embodiment in Figures 17A-17F offers several advantages over other scaffold designs. For example, the staggered proximal valleys 221 (which may also be present at the distal end of the scaffold) reduce the scaffold's fill volume at the locations of the staggered peaks. Additionally, when bent, the scaffold resists kinking and maintains a smooth curve within the bend zone. This can be advantageous when the scaffold is placed at a target site that requires the scaffold to assume a bent configuration, such as when the scaffold is placed in the ascending aorta and extends from there to the left ventricle. Additionally, the design is a closed-cell design (there are no free ends within the design; all ends are connected to another zone), yet retains sufficient flexibility along the length of the scaffold. This design also includes struts that individually terminate at the hub (proximal end of the scaffold) rather than being joined to other struts. The unconnected struts at the hub improve the manufacturing processes for heat treatment, membrane coating, and impeller loading. The advantages of the helical connecting member are set forth elsewhere in this specification.

[0221]

[0304] 17A-17F provide at least the exemplary advantages set forth herein, other scaffold designs are contemplated, and although some potential drawbacks of these alternative designs are discussed below, they (or aspects thereof) may still be used in the pump portions herein. For example, depending on the particular application, one or more features may be less important than others.

[0222]

[0305] 18A-B illustrate an expandable member 250 that is one of at least two expandable members (which may also be referred to herein as collapsible housings), such as the expandable member in FIGS. 3A-3D, each surrounding an impeller. The scaffold design in FIGS. 18A and B has more proximal struts 251 (only one labeled) than the design in FIGS. 17A-17E (there are nine, compared to four, in this exemplary embodiment). Having a separate expandable member 250 for each impeller provides the ability to have very different geometries for any of the individual impellers. Additionally, this design reduces the amount of scaffold material (e.g., nitinol) over the length of the scaffold (compared to full-length scaffolds herein), which may provide increased tracking when sheathed. 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 pathway may obstruct the outflow more than designs with fewer struts, such as the four struts in the embodiment in Figures 17A-F. Any other aspects of the expandable member herein, such as those described in Figures 3A-3D, may be incorporated by reference into this exemplary design. Figure 18B shows a top view of the scaffold in an unexpanded configuration to further illustrate the design.

[0223]

[0306] 19A and 19B illustrate a scaffold design having the same overall pattern as FIGS. 18A and B, but rather than the scaffold pattern being divided into two separate sections, the scaffold is a single elongated member as shown. FIG. 19A is a plan view of the unexpanded scaffold, while FIG. 19B is in the expanded configuration. The scaffold design in FIGS. 19A and B has proximal and distal ends 256 and 257 (i.e., hub attachment regions) with a continuous, integral structure rather than separate proximal hub ends as in the designs in FIGS. 17A-F. With this design and the design in FIGS. 17A-F, it may be easier to apply (e.g., coat) a membrane to a single scaffold (e.g., compared to separate, axially spaced expandable members, such as in FIGS. 18A-B). An exemplary drawback may be the relatively large number of proximal struts (nine in this embodiment), as in the design in FIGS. 18A-B, which may obstruct the outflow as blood exits the fluid lumen. This particular pattern may also be too stiff for some applications or access routes where increased bending and folding is desired. This design is relatively stiff over its axial length and does not easily bend or fold. In this design, each peak 258 and valley 260 in adjacent sections 261 is joined by a connector 259 that is radially aligned and parallel to the longitudinal axis of the fluid lumen.

[0224]

[0307] 20 illustrates an exemplary scaffold 280 that extends along the entire axial length from the proximal hub end 281 to the distal hub end 282, with the hub region having the same design as FIGS. 19A and B. The cells 383 in this design (only one is labeled and has a diamond pattern in the expanded configuration) have a reduced size compared to the design in FIGS. 18 and 19. The number of struts 284 in this design is also fewer than in FIGS. 18 and 19 (e.g., four at each end in this design compared to nine), because in this embodiment, only every other apices 285 at the scaffold end (only two are labeled) are coupled to (e.g., integral with) the proximal struts 284, rather than every apices. 18 and 19, which allows the membrane proximal end 286 (termination location) to be axially spaced a short distance from the end of the terminating apices 285, as shown. This added strut length therefore allows the membrane (or conduit) to be introduced into the sheath before the terminating apices, thereby reducing the chance of the proximal apices getting caught in the sheath during the sheathing process. This design makes it easier to apply the membrane to the scaffold along its length, as with other full-length scaffolds. The peaks and valleys in adjacent sections are each joined with short linear connectors. This design, like that in FIGS. 19A and B, is relatively stiff over its length and does not have particularly strong bending or folding features, which may be required for some applications. Additional potential drawbacks to this design include poor compression resistance during sheath removal, difficult sheath removal due to the scaffold geometry / pattern, and the expandable hub regions at the proximal and distal ends may be sensitive to fatigue and plastic deformation.

[0225]

[0308] 21A-C show a scaffold design similar to FIG. 20A, but with differences described below. In the central region "CR," between the proximal and distal impellers, the design aims for improved flexibility compared to FIGS. 20A and B. The benefits of such increased flexibility in this region are described herein. In the central region, alternating cell connections are removed, as shown, to improve flexibility in this region. In each axial section, alternating (radial) peaks are joined and alternating valleys are joined. These removed alternating cell connections create a spiral region 291 around the scaffold that does not contain connecting elements (see FIG. 21C), and a spiral region 292 around the scaffold that does contain connecting elements (see enlarged view in FIG. 21C). The spiral regions alternate between non-connected regions 291 and connected regions 292.

[0226]

[0309] The flexibility of the central region "CR" is increased in this design compared to the design in FIG. 20-B because of the non-connected region 291, and the scaffold has a relatively stiffer impeller region "IR" adjacent to the central region (not shown) where the impeller is disposed. The relatively increased stiffness in the impeller region IR helps maintain tip clearance and impeller concentricity. This scaffold pattern therefore results in a flexibility distribution along its length: a relatively less flexible proximal region ("IR"), a relatively more flexible central region "CR", and a relatively less flexible distal region "IR". The relatively less flexible regions (i.e., the two IR regions) are where the proximal and distal impellers may be disposed (not shown, although other embodiments are fully incorporated herein in this regard), with a relatively more flexible region in between. The benefits of relative flexibility in each of these regions are discussed elsewhere herein.

[0227]

[0310] However, in this design, the lack of alternating connectors in the central region CR can make the shape-setting and membrane application process more difficult. Unbonded (i.e., unconnected) areas of the scaffold in the central region can also rub against and cut into the membrane, increasing the likelihood of membrane failure at those locations. Additionally, the flexibility of the scaffold along its length may still be inadequate once the membrane is applied, depending on the application, target placement site within the patient, and access route. Additional potential drawbacks based on similar features are noted above with reference to FIG. 20 (e.g., sheathing difficulties due to the scaffold's geometry).

[0228]

[0311] 22A and 22B illustrate a scaffold design 300 similar to FIGS. 21A and B, but with differences explained below. Any feature from the scaffolds herein may be incorporated into this scaffold design. The design comprises peaks 301 and valleys 302 (only one set is labeled for clarity) of axially adjacent regions 303. 21A-B ), these peaks 301 and valleys 302 are connected by spring connectors 304 (only one is labeled for clarity), which join the radially aligned peaks 301 and valleys 302 of adjacent sections. The spring-like connectors 304 in this design provide better flexibility along the length of the scaffold compared to FIGS. 21A-B , in part because the spring connectors 304 provide individual cell articulation.

[0229]

[0312] The proximal and distal hub ends 305 and 306 each have four independent, free-standing (i.e., not connected to each other) members 307 (only one is labeled at the proximal end for clarity) that are connected to their respective hubs (not shown). Thus, the struts 308 (only one is labeled) have greater flexibility relative to each other. More or fewer members 307 may be present at each end (e.g., two members at each end), and the ends may have different numbers of members (e.g., four at the proximal end and eight at the distal end). The individual (i.e., unconnected) members 307 at the hub ends facilitated the manufacturing processes of heat treatment, membrane coating, and impeller loading. Some potential drawbacks to this design include the possibility of strut buckling during sheath sheathing removal due to insufficient compression resistance, depending on the specific application. Additionally, sheath sheathing forces may be undesirably high, which may be at least partially attributable to the membrane. Additionally, flexibility may be considered insufficient once the membrane is applied to the scaffold.

[0230]

[0313] In a particular exemplary application in which a pump portion is navigated for placement across an aortic valve (embodiments of which are described herein), the scaffold design in FIGS. 17A-F may provide the benefits set forth herein, while the scaffolds in FIGS. 18-22 may be suboptimal in one or more respects for this particular application (e.g., not being flexible enough, a suboptimal process of membrane application to the scaffold, etc.). However, in some applications, one or more features of the scaffolds in FIGS. 18-22 may be desirable. For example, a blood pump may be placed where flexibility is not important or where relatively high stiffness over the length of the scaffold is desired or tolerated. Thus, any of the features in the scaffold designs in FIGS. 18-22 may be combined in any suitable combination to result in a scaffold structure that provides the desired functionality. For example, the designs in FIGS. 17A-F may instead have a hub region that is not a separate member (as in FIGS. 22A-B) but instead is continuous like the designs in FIGS. 19-21.

[0231]

[0314] FIG. 23 illustrates the proximal region of an exemplary pump portion, the features of which may be incorporated into any of the pump portions herein. Not all of the features in the embodiment in FIG. 23 need be included in the pump portion shown. The proximal end 310 of the fluid lumen has a flared radially outward configuration as shown (the end of the lumen is furthest radially outward), with a smooth curve, which may promote radial flow of the impeller (optionally the proximal impeller, and optionally one of multiple impellers) at the outflow section. The distal end of the fluid lumen may also have the same or similar type of flared configuration (not shown), with or without a flared proximal end. The flared distal end configuration limits the amount of contact between the stiffer portions of the pump segment and the left ventricular wall (if that is where it resides) and can reduce the likelihood of tissue coming into contact with the rotating impeller, which can prevent or minimize blockage of the pump segment inlet, and it can help prevent migration of the pump segment by acting as an enlarged interface area that can conform to native tissue and prevent further migration (e.g., engage native valve tissue such as the leaflets and prevent the pump segment from passing through the valve opening). Any other suitable aspects of the present disclosure are incorporated by reference into this embodiment.

[0232]

[0315] Some embodiments of the disclosure herein describe pump portions that include one or more central members (which may also be referred to herein as "middle members") that are optionally stationary and optionally between two first and second impellers (see, e.g., FIGS. 10-13C). FIG. 24 is a perspective view illustrating a portion of an exemplary conduit (optionally collapsible) having a central member as incorporated herein. Incorporated herein in this context includes central members that are integrally formed with the conduit as well as central members that are attached to a collapsible conduit and are thereby considered part of a collapsible blood conduit. For example, the central member may have an outer surface 313 that is attached (e.g., glued) to the inner surface of any of the collapsible conduits herein (e.g., attached to a flexible membrane portion of the conduit) and are thereby considered part of the collapsible conduit. The central member shown in FIG. 24 may have one or more flow-modifying elements (e.g., blades) 314 extending radially inward from a peripheral portion 315 toward (but not from) a central region 316, but not connected to each other at a central hub. The flow-modifying elements 314 (e.g., blades) in FIG. 24 (or any other embodiment or claim herein) that are portions of an object not in rotational operation with the impellers may be referred to herein as portions of a stator, or as diffuser vanes. The flow-modifying elements may each have a variety of transverse geometries. The flow-modifying elements may be configured to increase fluid pressure between the impellers (by reducing velocity) and / or reduce swirl velocity at their location, optionally between the distal and proximal impellers.

[0233]

[0316] In some embodiments, the central member may have multiple blade-like extensions that are cords of the peripheral curved portion (which may have a circular cross-section), so that the cords do not have free ends as does flow-modifying element 314 in FIG. 24. One or more cords may extend from different regions of the peripheral curved portion to different regions of the peripheral curved portion. When multiple cords are present, and in an end cross-sectional view, the cords may have different lengths between the two end points where they join (integrally or attached) to the outer peripheral region.

[0234]

[0317] FIG. 25 is a perspective view of a proximal portion of a pump portion including an expandable scaffold and at least one impeller (not labeled but easily identifiable based on other figures herein). The pump portion also includes an intermediate member 316, which is similar in some respects to other intermediate or central members herein. The intermediate member 316 includes flow-altering elements 317 (e.g., blades), each of which has an outermost engagement feature 318 (e.g., a flange) configured to stably align (i.e., contact or mate) with a corresponding mating feature (e.g., a peak or valley) in the scaffold. The blade / scaffold engagement can cause the blade to fold during radial compression and sheathing of the scaffold. Additionally, the blade and scaffold can be aligned or joined using various techniques. For example, the flow-altering elements and scaffold can be joined by spot welding. In some embodiments, the ends of the flow modifying elements 317 may have features that connect to features on the central hub 319 with locating features on the central radial bearing rather than the drive cable (e.g., a dovetail connection). This may simplify manufacturing. The outer housing in this embodiment may be any of the outer housings herein.

[0235]

[0318] One or more impellers that are part of a blood pump system (such as any herein) may be rotated at relatively high speeds, such as 10,000-50,000 RPM. The impeller may be rotated by being in rotational communication with a drive member (e.g., a drive cable) or other component in rotational communication with 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, vibration to the drive member, and possibly require the drive member to be lubricated (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 still allowing the impeller to rotate at a desired higher RPM. One embodiment of the present disclosure is a blood pump including one or more drive members that can be rotated at a lower RPM than one or more impellers. This may reduce drive member wear, require less 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 advantageous in cardiogenic shock conditions.

[0236]

[0319] The rotary drive member (e.g., drive cable, magnetic stator) can rotate slower than one or more impellers. In some exemplary embodiments, the rotary drive member may rotate between 0 and 1 times (1×) the impeller RPM. For example, if any impeller rotates at 20,000 RPM, the drive member may rotate between 0 and 20,000 RPM. In some embodiments, the drive member may rotate between 0.25 and 1×, or 0.3 and 1×, or 0.4 and 1×, or 0.5 and 1×, or 0.6 and 1×, or 0.7 and 1×, or 0.8 and 1×, or 0.9 and 1× of the impeller RPM.

[0237]

[0320] FIG. 26A illustrates only a portion of an exemplary blood pump to illustrate an exemplary embodiment of how the impeller rotates faster than the drive member. The exemplary speed-up mechanism in FIG. 26A utilizes gearing to achieve speed-up, with the output gear having a smaller diameter than the input gear, causing a higher speed at the output gear shaft around which the output shaft rotates. Thus, the output shaft (and the impeller to which it is coupled) rotates faster than the input shaft (e.g., drive member). FIG. 26B illustrates how multiplicative gearing is used to obtain a larger difference in speed (compared to FIG. 26A) between the input shaft (e.g., drive member) and output shaft 2 (to which the impeller is coupled). Input gear 2 has a larger diameter than output gear 2.

[0238]

[0321] Additionally, gearing systems such as planetary gearboxes and magnetic gearboxes may also be used to increase the speed of one or more impellers relative to the rotation of the input drive member.

[0239]

[0322] FIG. 27 illustrates an exemplary design of pump section 140 that includes at least one elongated member 143 (e.g., a pull wire) that, when stretched, induces bending of at least a portion of the pump section. The elongated member can extend as far distally (or further distally or further proximally) between the distal and proximal impellers, causing a bend to form between the two impellers after the pump section is deployed from the delivery system. For example, the handle can include an actuator (lever, button, etc.) that, when actuated, stretches one or more elongated members, causing the region to deflect. Any known elongated member (e.g., pull wire) design and use can be incorporated into this embodiment to implement one or more deflectable regions. For example, the catheter can include one or more pull wire lumens extending along any portion thereof, with the pull wire attached to one or more portions of the catheter at its distal end depending on the location of the desired deflection region.

[0240]

[0323] The following disclosure provides exemplary method steps that may be performed when using the blood pump described herein or any of its portions. It should be understood that not all of the steps need be performed, but rather the steps are intended to be illustrative procedures. It is also contemplated that the order of one or more steps may sometimes be varied, if preferred.

[0241]

[0324] Prior to use, the blood pump is inflated with a sterile solution (e.g., heparinized) to remove any air bubbles from any fluid lines, rinsing the lumen (including any annular spaces) and pump assembly. The catheter may be prepared for use by priming it with saline (physiological saline). 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, which is used to prime the catheter and remove air bubbles.

[0242]

[0325] After priming the catheter, access to the patient's vasculature may be gained using an appropriately sized introducer sheath (for example, but not limited to, via femoral access). Using standard valve crossing techniques, the diagnostic pigtail catheter may then be advanced over, for example, a 0.035 inch guidewire until the pigtail catheter is safely positioned within the target site (e.g., the left ventricle). The guidewire may then be removed, and a second wire 320 (e.g., a 0.018 inch wire) may be inserted through the pigtail catheter. The pigtail catheter may then be removed (see FIG. 28A), and the blood pump 321 (including the catheter, catheter sheath, and pump portion within the sheath, see FIG. 28B) may be advanced over the second wire toward and into the target site (e.g., the left ventricle "LV"), such as extending to the aortic valve "AV", using, for example, one or more radiopaque markers to position the blood pump.

[0243]

[0326] Once proper placement is confirmed, the catheter sheath 322 (see FIG. 28C) can be retracted, first exposing the distal region of the pump portion. In FIG. 28C, the distal region of the expandable housing is released from the sheath 322 and expanded, as is 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. Continued retraction of the sheath 322 past the proximal end of the housing 323 allows the housing 323 and the proximal impeller 325 to expand (see FIG. 28D). The inflow region (indicated by the arrow, although the impeller is not yet rotating) and the distal impeller are within the left ventricle. The outflow region (indicated by the arrow, although the impeller is not yet rotating) and the proximal impeller are within the ascending aorta AA. As described in more detail herein, the region of the outer housing between the two impellers, which may be more flexible than the housing region surrounding the impellers, spans the aortic valve AV. In the exemplary operating position as shown, the inlet portion of the pump portion is distal to the aortic valve within the left ventricle, and the outlet of the pump portion is proximal to the aortic valve within the ascending aorta (“AA”).

[0244]

[0327] A second wire (e.g., a 0.018 inch guidewire) may then be moved prior to operation of the pump assembly (see FIG. 28E). If desired or necessary, the pump portion may be deflected (actively or passively) at one or more locations as described herein, as illustrated in FIG. 28F. For example, the region between the two impellers may be deflected by stretching an extension member that extends to the location between the two impellers. The deflection may be desired or required to accommodate a particular anatomy. If necessary, the pump portion may be repositioned to achieve the intended arrangement, such as, for example, having a first impeller on one side of the heart valve and a second impeller on a second side of the heart valve. An exemplary pump portion with an exemplary extension member is shown in FIG. 27. It should be understood that in FIG. 28F, the pump portion does not in any way interfere with or interact with the mitral valve, even though it may appear from the illustration to do so.

[0245]

[0328] Any number of purge lines may then be attached to a proximal portion of the blood pump disposed outside the patient. For example, fluid inlet and outlet lines may be attached to one or more fluid ports on the proximal portion of the blood pump. A purge process may then be initiated to move fluid through at least one fluid passageway into the blood pump. One or more verification steps may be performed to verify that the purge is working as intended before turning on the pump. The pump assembly may then be operated, causing rotation of one or more impellers. Any one of flow rate, pressure, and motor operation may be constantly monitored.

[0246]

[0329] 29-35B illustrate additional exemplary intermediate members, other examples of which are provided herein, that may function at least in part as a stator (and may also provide radial support), as well as multiple fluid modifiers that may be disposed between the distal and proximal impellers and adapted to affect blood flow between the impellers. Any aspect of FIGS. 29-35B may be incorporated with any other aspect of a blood pump herein. For example, impellers may not be shown in FIGS. 29-35B for clarity, but it should be understood that one or more impellers may be incorporated into these embodiments.

[0247]

[0330] 29A and 29B illustrate an exemplary blood conduit 402 having flow modifiers 402 extending radially inward from the inner surface of the conduit. The flow modifiers (e.g., blades) do not extend to a central hub, but rather they have a radially inner free end, which can be seen more clearly in the end view of FIG. 29B. The flow modifiers 402 (e.g., stator elements) may be individually molded and then secured to the inner surface (e.g., membrane) of the conduit. The conduit 402 may also include any other support member herein, such as, but not limited to, any of the nitinol scaffolds herein. The flow modifiers may have a slight curvature to them, which can be seen in FIG. 29B. The flow modifiers 402 may be considered part of one stator.

[0248]

[0331] 30A, 30B, 31A, and 31B illustrate an exemplary support member having multiple apertures therein, each configured to receive and align with a flow modifier 408 therethrough, with the flow modifier 408 having an enlarged region 409 that aligns with a portion of the support member to help stabilize the flow modifier's position relative to the support member. The location of the elongated apertures 407 establishes the position and orientation of the flow modifier (e.g., stator element). After the flow modifier is inserted into the aperture, a conduit material (e.g., a film) can be sprayed onto the subassembly to further secure the modifier 408 in place. Alternatively, the material can be sprayed first, and then an aperture 407 is cut through which the modifier can be inserted. An additional layer of material can be sprayed to create a seal. The flow modifier 408 can be considered part of one stator.

[0249]

[0332] 32A-32C illustrate an exemplary support member 420 (e.g., a scaffold, e.g., Nitinol) with one or more flow modifiers 421 integrated (unitary) into an expandable scaffold structure that can be oriented radially inward in a shape-setting process, thus creating a flow modifier (e.g., a stator). A material (e.g., a polymer) can be applied to the member 420 to create a blood conduit. The scaffold and flow modifiers can also be designed to be manufactured separately and connected after a membrane material (e.g., a polymer) is applied to the scaffold. The scaffold can have any pattern described herein. The flow modifier 421 can be considered part of one stator.

[0250]

[0333] 33A and 33B illustrate an exemplary foldable pump portion 440 including a conduit 441, a distal impeller 442, and a proximal impeller 443. The pump also includes multiple flow modifiers 445 secured to struts 444 within the pump. The struts may be portions of the distal impeller basket, examples of which are described herein. In this embodiment, the flow modifiers are secured to proximal struts of the distal impeller basket, but may also be secured to distal or proximal struts of the proximal impeller basket. The flow modifiers in this embodiment may be flexible membranes or other relatively flexible and thin materials. The flow modifiers are positioned to manage flow on the struts as well as to support directing flow longitudinally through the blood conduit. To assist in the flow modifier 445, the scaffold is secured to longitudinal spine elements 449 (shown in phantom as these elements are covered by flow modifier material 445). The flow modifiers (e.g., stators) can be flexible polymers with or without fabric reinforcement to aid in collapsibility and sheathing. The flow modifiers 445 can be considered part of one stator.

[0251]

[0334] The subsequent disclosure, including Figures 34, 35A, and 35B, may be referred to as an embracing foldable diffuser to increase outflow pressure. Figure 34 illustrates the concept of using embracing vanes on the diffuser / stator. Figures 35A and 35B illustrate (A) a side view and (B) a top view of the embracing vane profile. The diffuser is generally designed as a stationary component to convert the flow's rotational velocity / energy into the desired additional pressure by eliminating the flow's vortex (i.e., removing the fluid's rotational velocity component). The shape of the diffuser (stator) plays an important role in the efficiency of this process. The pump portion here is entirely collapsible for delivery (e.g., to the aortic valve) and then expanded for later use.

[0252]

[0335] 34-35B illustrate an example concept where the diffuser wings have a special geometry / configuration that hugs / overlaps each other to allow for compression of the pump to the desired delivery profile size. Concepts found elsewhere in this specification related to flow modifiers may be incorporated into these embodiments as well (e.g., scaffolds that align with the flow modifiers).

[0253]

[0336] 34, the diffuser may be designed to be compliant, part of the shroud / blood conduit, and adapted to further increase pressure. In some embodiments, a resilient material such as Nitinol may be used for the inner portion of the diffuser, which may be coated with a material (e.g., a polymer, which may be the same as the blood conduit material) to create the diffuser outer surface.

[0254]

[0337] Any of the stators herein, including any of the flow modifying elements (a.k.a. flow modifiers), may be incorporated with any suitable aspect of any shroud, housing, blood flow conduit, impeller basket, etc., described herein, including any method of manufacturing the same.

[0255]

[0338] In some embodiments, the diffuser may be made of the same or similar material as the blood conduit membrane. Injection molding may be used to make the diffuser.

[0339] An exemplary clinical advantage may be to use a pump with a diffuser to still increase pressure to a desired range, while keeping the drive cable / pump RPM within reasonable limits to avoid hemolysis. The present invention includes the following aspects. 1. A pump part, a collapsible blood conduit defining a blood flow lumen between an inflow portion and an outflow portion; a distal foldable impeller axially spaced from the proximal foldable impeller, wherein at least a portion of each of the distal and proximal foldable impellers is disposed between the inlet and outlet portions; a pump portion including: one or more stators within the blood flow lumen, the one or more stators being axially disposed between the distal impeller and the proximal impeller. An intravascular blood pump comprising: 2. A blood pump as described in claim 1, wherein the one or more stators are each fixed to a surface of the collapsible blood conduit and extend radially inward therefrom. 3. A blood pump as described in claim 1, wherein each of the one or more stators comprises a plurality of blood flow modifiers, each of which has at least one axially extending surface configured to increase pressure between the distal impeller and the proximal impeller. 4. A blood pump as described in claim 1, wherein the stator does not include a central hub from which the plurality of flow-modifying elements extend. 5. The blood pump of claim 1, wherein the stator includes a central hub from which a plurality of flow-modifying elements extend. 6. A blood pump as described in claim 1, wherein the one or more stators each include a plurality of blood flow modifiers integrally formed with at least a portion of the collapsible blood conduit. 7. A blood pump as described in claim 6, wherein the one or more flow modifiers are integral with the scaffold of the collapsible blood conduit. 8. A blood pump as described in claim 7, wherein the one or more flow modifiers are biased into a deployed configuration in which they extend radially inward relative to the outer region of the scaffold. 9. A blood pump as described in claim 1, wherein the stator is fixed to an outer annular member that does not extend axially entirely from the inlet to the outlet, and includes a plurality of blood flow modifiers extending radially inward therefrom. 10. A blood pump as described in claim 9, wherein the outer annular member provides radial support to the collapsible blood conduit. 11. A blood pump as described in claim 1, wherein the stator comprises a plurality of blood flow modifiers (e.g., blades) formed from a polymeric material. 12. A blood pump as described in claim 1, wherein the one or more stators each comprise a plurality of blood flow modifiers having radially outer ends configured to be shaped to stably align with a portion of the collapsible blood conduit. 13. A blood pump as described in claim 12, further comprising a scaffold having one or more blood flow modifier apertures therethrough, each of said radially outer ends having a configuration shaped to stably align with one of the blood flow modifier apertures. 14. The blood pump of claim 13, further comprising a membrane layer extending over the scaffold and further securing one or more flow modifiers to the apertures. 15. A blood pump as described in claim 14, wherein the apertures extend axially and are parallel to the long axis of the scaffold. 16. A blood pump as described in claim 12, further comprising a self-expanding scaffold, wherein the one or more blood flow modifiers have radially outer ends having a configuration that is shaped to stably align with the self-expanding scaffold. 17. A blood pump as described in claim 13, wherein the one or more blood flow modifiers are made of a material different from the scaffold material, and the material is more flexible than the scaffold material. 18. A blood pump as described in claim 17, wherein one or more blood flow modifiers are made of a polymeric material. 19. A blood pump as described in claim 1, wherein the one or more stators each include a plurality of blood flow modifiers made of a polymeric material. 20. A blood pump as described in claim 1, wherein each of the stators comprises at least two blood flow modifiers, optionally four blood flow modifiers. 21. A blood pump as described in claim 1, wherein the one or more stators each include a plurality of blood flow modifiers, each of the one or more blood flow modifiers being fixed to one of the one or more struts, the struts defining a portion of an expandable basket in which the proximal or distal impeller is disposed. 22. A blood pump as described in claim 21, wherein the pump portion further comprises a membrane layer secured (directly or indirectly) to the expandable basket, the membrane layer at least partially defining the blood conduit. 23. The blood pump of claim 22, wherein the one or more struts are proximal struts of an expandable basket. 24. A blood pump as described in claim 23, wherein the expandable basket is a distal basket in which the distal impeller is disposed, and the pump portion further comprises a proximal expandable basket in which the proximal impeller is disposed. 25. A blood pump as described in claim 23, wherein the expandable basket is a proximal basket in which the proximal impeller is disposed, and the pump portion further comprises a distal expandable basket in which the distal impeller is disposed. 26. The blood pump of claim 21, wherein the struts are at a non-orthogonal angle to the longitudinal axis of the pump portion at the location of the struts. 27. A blood pump as described in claim 1, wherein the one or more stators each include a plurality of blood flow modifiers, each of the one or more blood flow modifiers having an inner free end disposed parallel to the longitudinal axis of the pump section in which the flow modifier is disposed. 28. A blood pump as described in claim 27, wherein the collapsible blood conduit includes one or more bends formed therein along its length, the one or more bends being axially spaced from the one or more blood flow modifiers. 29. The blood pump described in claim 1, wherein the one or more stators include one or more blood flow modifiers integrally formed with at least one other component of the collapsible blood conduit. 30. A blood pump as described in claim 1, wherein the one or more stators are fixed to the collapsible blood conduit and include one or more blood flow modifiers having a radially outer region extending therefrom at least 1 mm and no more than 15 cm along a length thereof. 31. A blood pump as described in claim 30, wherein the one or more blood flow modifiers are fixed to the collapsible blood conduit and have a radially outermost section extending along a length of at least 1 mm and no more than 10 cm therefrom, optionally no more than 9 cm, no more than 8 cm, no more than 7 cm, no more than 6 cm, or no more than 5 cm. 32. The blood pump described in claim 1, wherein the one or more stators are fixed to the blood conduit longer than the radially inner edge of the blood flow modifier and include one or more blood flow modifiers having a radially outer section extending therefrom. 33. A blood pump as described in claim 1, wherein the one or more stators include one or more blood flow modifiers having distal and proximal end surfaces, at least one of the ends being tapered. 34. A blood pump as described in claim 1, wherein the pump portion includes a membrane that helps secure one or more blood flow modifiers to the blood conduit. 35. The blood pump described in claim 1, wherein the one or more stators include one or more blood flow modifiers adapted to be self-expanding. 36. The blood pump described in claim 1, wherein the one or more stators include a plurality of blood flow modifiers, each of the plurality of blood flow modifiers including an axially extending surface configured to transition the blood flow to laminar flow. 37. A blood pump as described in claim 1, wherein the one or more blood flow modifiers are foldable between an expanded configuration and a collapsed configuration. 38. The blood pump described in claim 1, wherein the one or more stators include one or more blood flow modifiers that are at least one of movable and reconfigurable between a first position and a deployed position. 39. The blood pump described in claim 1, wherein the one or more stators include one or more blood flow modifiers positioned adjacent to at least one of the proximal impeller and the distal impeller when the proximal and distal impellers are in an extended configuration. 40. A blood pump as described in claim 39, wherein the one or more blood flow modifiers are positioned adjacent to the proximal impeller and the distal impeller. 41. A blood pump as described in claim 39, wherein the one or more blood flow modifiers are positioned adjacent to the proximal impeller but not adjacent to the distal impeller. 42. A blood pump as described in claim 39, wherein the one or more blood flow modifiers are positioned adjacent to the distal impeller but not adjacent to the proximal impeller. 43. The blood pump of claim 1, wherein the one or more stators include one or more flow modifiers closer to the proximal impeller than to the distal impeller. 44. The blood pump of claim 1, wherein the one or more stators include one or more blood flow modifiers closer to the distal impeller than to the proximal impeller. 45. A blood pump as described in claim 1, wherein the one or more stators include one or more blood flow modifiers, and a first end of the one or more blood flow modifiers is 0.01 mm to 20 mm from at least one of the distal and proximal impellers. 46. ​​A blood pump as described in claim 1, wherein the one or more stators include one or more blood flow modifiers, and a first end of the one or more blood flow modifiers is within 10x bore diameters of at least one of the distal and proximal impellers. 47. A blood pump as described in claim 1, wherein the one or more stators include one or more blood flow modifiers fixed to (optionally integral with) an annular member that provides radial support for one or more of the impeller baskets or blood conduit scaffolds. 48. A blood pump as described in claim 47, wherein the annular member is attached to a blood conduit. 49. The blood pump of claim 1, wherein the one or more stators include one or more blood flow modifiers that are part of a foldable intermediate member positioned and adapted to provide radial support to the blood conduit. 50. The blood pump described in claim 1, wherein the one or more stators include one or more blood flow modifiers that are part of a foldable intermediate member positioned to maintain a tip clearance between at least one of the impellers and the blood conduit. 51. The blood pump described in claim 1, wherein the one or more stators include one or more blood flow modifiers, a distal region of the one or more fluid modifiers configured to act as a diffuser for fluid in the fluid conduit to recover pressure from the distal impeller, and a proximal region of the one or more fluid modifiers configured to act as a stator to direct flow toward the proximal impeller. 52. A pump part comprising: a collapsible blood conduit defining a blood flow lumen between an inflow portion and an outflow portion; a distal foldable impeller axially spaced from the proximal foldable impeller, wherein at least a portion of each of the distal and proximal foldable impellers is disposed between the inlet and outlet portions; one or more stators, each including one or more flow modifiers axially disposed distally and between the foldable impellers; a pump portion including: An intravascular blood pump, wherein each of the one or more blood flow modifiers has at least one axially extending surface configured to increase fluid pressure between the distal impeller and the proximal impeller. 53. The blood pump of claim 52, wherein at least one axially extending surface is configured to transition the flow to laminar flow. 54. A blood pump as described in claim 52, wherein the one or more blood flow modifiers are fixed to a surface of the collapsible blood conduit and extend radially inward therefrom. 55. The blood pump of claim 52, wherein the one or more flow modifiers include any feature of any of the flow modifiers herein. 56. A pump part comprising: a collapsible blood conduit defining a blood flow lumen between an inflow portion and an outflow portion; a proximal foldable impeller axially spaced from the distal foldable impeller, wherein at least a portion of each of the distal and proximal foldable impellers is disposed between the inlet section and the outlet section; a proximal collapsible basket in which the proximal impeller is disposed, the proximal collapsible basket providing radial support to the blood conduit at the location of the proximal impeller; a distal collapsible basket having a distal impeller disposed therein, the distal collapsible basket providing radial support to the blood conduit at the location of the distal impeller; a collapsible radial support member supporting one or more of a distal region of the proximal collapsible basket, a proximal region of the distal collapsible basket, or a central region of a blood conduit axially disposed between the proximal basket and the distal basket; An intravascular blood pump comprising a pump portion including: 57. The blood pump of claim 56, wherein the radial support member includes an annular circumferential member and a plurality of support elements extending radially inward from the annular circumferential member. 58. A blood pump as described in claim 57, wherein the plurality of support elements do not extend to the central hub. 59. A blood pump as described in claim 57, wherein the plurality of support elements extend to a central hub. 60. A blood pump as described in claim 57, wherein the plurality of support elements have radially inner free ends. 61. The blood pump of claim 57, wherein the radial support member supports a distal region of the proximal basket. 62. The blood pump described in claim 57, further comprising a second radial support member axially spaced from the radial support member, the second radial support member positioned to radially support a proximal region of the distal basket. 63. The blood pump of claim 62, wherein the second radial support member includes a second annular circumferential member and a plurality of second support elements extending radially inward from the second annular circumferential member. 64. The blood pump of claim 56, wherein the radial support member supports a proximal region of the distal basket. 65. The blood pump of claim 56, wherein the collapsible radial support member comprises a stator including one or more blood modifying elements, such as any of the blood modifying elements herein. 66. A pump part comprising: a collapsible blood conduit defining a blood flow lumen between an inflow portion and an outflow portion; a proximal foldable impeller axially spaced from the distal foldable impeller, wherein at least a portion of each of the distal and proximal foldable impellers is disposed between the inlet section and the outlet section; a proximal collapsible basket in which the proximal impeller is disposed, the proximal collapsible basket providing radial support to the blood conduit at the location of the proximal impeller; a distal collapsible basket having a distal impeller disposed therein, the distal collapsible basket providing radial support to the blood conduit at the location of the distal impeller; a foldable radial support member including an annular peripheral member and a plurality of support elements extending radially inward from the annular peripheral member; a pump portion including: An intravascular blood pump, wherein the foldable radial support radially supports one or more of a distal region of the proximal foldable basket, a proximal region of the distal foldable basket, or a central region of a blood conduit axially disposed between the proximal basket and the distal basket. 67. A blood pump as described in claim 66, wherein the plurality of support elements do not extend to the central hub. 68. A blood pump as described in claim 66, wherein the plurality of support elements extend to a central hub. 69. A blood pump as described in claim 68, wherein the plurality of support elements have radially inner free ends. 70. The blood pump of claim 68, wherein the foldable radial support is radially disposed within at least one of the distal region of the proximal foldable basket and the proximal region of the distal foldable basket. 71. A blood pump as described in claim 66, wherein the foldable radial support is radially disposed within a distal region of the proximal basket, and the proximal basket includes a plurality of proximal struts but does not include a plurality of distal struts. 72. The blood pump of claim 66, wherein the foldable radial support comprises a stator, the stator including a plurality of support elements. 73. A blood pump as described in claim 72, wherein the plurality of support elements are configured to increase fluid pressure between the distal impeller and the proximal impeller. 74. A method of deploying an intravascular blood pump across an aortic valve, comprising: advancing an intravascular blood pump to the region of the heart valve, the intravascular blood pump comprising a distal basket, a distal impeller, a proximal basket, a proximal impeller, and a blood flow conduit; deploying the distal basket and the distal impeller, respectively, from a collapsed delivery configuration to a deployed configuration; positioning at least a portion of the distal basket within the left ventricle such that a distal end of the distal basket is distal to the aortic valve leaflets; deploying the proximal basket and the proximal impeller, respectively, from a collapsed delivery configuration to a deployed configuration; positioning at least a portion of the proximal basket within the ascending aorta such that a proximal end of the proximal basket is proximal to the aortic valve cusps; positioning a central region of the conduit axially between the deployed distal basket and the deployed proximal basket adjacent the aortic valve leaflets; starting the distal impeller to propel blood toward the proximal impeller; modifying blood flow with at least one flow modifying member at at least one flow modifying location proximal to the distal impeller and distal to the proximal impeller; starting the proximal impeller to propel blood toward the outflow portion of the conduit; A method comprising: 75. The method of claim 74, wherein the step of altering the flow of blood with at least one flow altering member includes increasing fluid pressure between the distal impeller and the proximal impeller. 76. A method of deploying an intravascular blood pump across an aortic valve, comprising: advancing an intravascular blood pump to the region of the heart valve, the intravascular blood pump comprising a distal basket, a distal impeller, a proximal basket, a proximal impeller, and a blood flow conduit; deploying the distal basket and the distal impeller, respectively, from a collapsed delivery configuration to a deployed configuration; positioning at least a portion of the distal basket within the left ventricle such that a distal end of the distal basket is distal to the aortic valve leaflets; deploying the proximal basket and the proximal impeller, respectively, from a collapsed delivery configuration to a deployed configuration; positioning at least a portion of the proximal basket within the ascending aorta such that a proximal end of the proximal basket is proximal to the aortic valve cusps; positioning a central region of the conduit axially between the deployed distal basket and the deployed proximal basket adjacent the aortic valve leaflets; starting the distal impeller to propel blood toward the proximal impeller; activating the proximal impeller to propel blood toward the outflow portion of the conduit; deploying the foldable radial support to radially support at least one of a distal region of the proximal foldable basket, a proximal region of the distal foldable basket, or a central region of a blood conduit axially disposed between the proximal basket and the distal basket; A method comprising: 77. The method of claim 76, wherein the step of deploying the foldable radial support includes deploying an annular circumferential member and a plurality of support elements extending radially inward from the annular circumferential member. 78. The method of claim 77, wherein the step of deploying the collapsible radial support includes radially deploying an annular circumferential member within a proximal region of the distal basket. 79. The method of claim 77, wherein the step of deploying the collapsible radial support includes radially deploying an annular circumferential member within a distal region of the proximal basket. 80. The method of claim 79, further comprising the step of deploying a second foldable radial support within the proximal region of the distal basket to radially support the proximal region of the distal basket.

Claims

1. A pump portion, a collapsible blood conduit defining a blood flow lumen between an inflow portion and an outflow portion; a distal foldable impeller and a proximal foldable impeller, the distal foldable impeller being axially spaced from the proximal foldable impeller, and at least a portion of each of the distal and proximal foldable impellers being disposed between the inlet portion and the outlet portion; one or more stators within the blood flow lumen, the one or more stators being axially disposed between the distal and proximal foldable impellers and configured to increase an axial to radial flow ratio of blood flowing through the blood flow lumen. Equipped with An intravascular blood pump, wherein each of the one or more stators comprises a plurality of blood flow modifiers, each of the plurality of blood flow modifiers being fixed to one of one or more struts, the struts defining a portion of an expandable basket in which the proximal foldable impeller or the distal foldable impeller is disposed.

2. The intravascular blood pump of claim 1 , wherein the one or more stators extend radially inward from a surface of the strut.

3. An intravascular blood pump as described in claim 1, wherein each of the plurality of blood flow altering bodies has at least one axially extending surface configured to increase pressure between the distal foldable impeller and the proximal foldable impeller.

4. The intravascular blood pump of claim 1 , wherein the stator does not include a central hub from which the plurality of flow modifiers extend.

5. The intravascular blood pump of claim 1 , wherein the stator includes a central hub from which the plurality of flow modifiers extend.

6. The intravascular blood pump of claim 1 , wherein the plurality of flow modifiers are integrally formed with at least a portion of the strut.

7. 7. The intravascular blood pump of claim 6, wherein the plurality of blood flow modifiers are biased into a deployed configuration in which they extend radially inward relative to an outer region of the collapsible blood conduit.

8. The intravascular blood pump according to claim 1 , wherein the plurality of blood flow modifiers are formed from a polymeric material.

9. 2. The intravascular blood pump of claim 1, wherein the plurality of blood flow modifiers each have a radially outer end having a configuration shaped for stable alignment with a portion of the collapsible blood conduit.

10. 10. The intravascular blood pump of claim 9, wherein the collapsible blood conduit comprises a scaffold having one or more blood flow modifier apertures therethrough, and wherein each of the radially outer ends has a configuration shaped to stably align with one of the blood flow modifier apertures.

11. The intravascular blood pump of claim 10 , further comprising a membrane layer extending across the scaffold and further securing the plurality of flow modifiers to the flow modifier apertures.

12. The intravascular blood pump of claim 11 , wherein the flow modifier apertures extend axially and are parallel to a longitudinal axis of the scaffold.

13. 10. The intravascular blood pump of claim 9, wherein the collapsible blood conduit comprises a self-expanding scaffold, and the plurality of blood flow diverters have radially outer ends having a configuration shaped to stably mate with the self-expanding scaffold.

14. 11. The intravascular blood pump of claim 10, wherein the plurality of flow modifiers are made of a different material than the scaffold material, the material being more flexible than the scaffold material.

15. 10. The intravascular blood pump of claim 1, wherein each of said one or more stators comprises at least two flow modifiers, optionally four flow modifiers.

16. The intravascular blood pump of claim 1 , wherein the pump portion further comprises a membrane layer secured to the expandable basket, the membrane layer at least partially defining the collapsible blood conduit.

17. 17. The intravascular blood pump of claim 16, wherein the one or more struts are proximal struts of the expandable basket.

18. 18. The intravascular blood pump of claim 17, wherein the expandable basket is a distal basket in which the distal collapsible impeller is disposed, and the pump portion further comprises a proximal expandable basket in which the proximal collapsible impeller is disposed.

19. 18. The intravascular blood pump of claim 17, wherein the expandable basket is a proximal basket in which the proximal collapsible impeller is disposed, and the pump portion further comprises a distal expandable basket in which the distal collapsible impeller is disposed.

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