Ventricular assist device

Abstract

To provide apparatus and methods including placing within a blood vessel of a subject an impeller.SOLUTION: Apparatus and methods are described including placing within a blood vessel of a subject an impeller (50), the impeller including at least one helical elongate element (52), and a spring (54), the spring being disposed inside of, and coaxially with, the helical elongate element. A film (56) of material is supported between the helical elongate element and the spring. Blood is pumped through the subject's blood vessel, using the impeller. Other applications are also described.SELECTED DRAWING: Figure 4A

Description

[Technical Field]

[0001] This application claims priority from the following applications: U.S. Provisional Patent Application No. 62 / 412,631 to Tuval, entitled "Ventricular assist device," filed October 25, 2016; and U.S. Provisional Patent Application No. 62 / 543,540 to Tuval, filed August 10, 2017, entitled "Ventricular assist device."

[0002] Both of the above applications are incorporated herein by reference.

[0003] Field of Invention Embodiments Some applications of the present invention relate generally to medical devices, and more particularly to ventricular assist devices and methods of use thereof. [Background technology]

[0004] background Ventricular assist devices are used to assist the cardiovascular system in patients suffering from heart failure. Most commonly, left ventricular assist devices are applied to the failing heart to assist left ventricular function. In some cases, right ventricular assist devices are used to assist right ventricular function. Summary of the Invention

[0005] Overview of the embodiment According to some applications of the present invention, an impeller includes a helical elongate element, a spring disposed within and coaxially with the helical elongate element, and a film of material supported between the helical elongate element and the spring. For some applications, the impeller comprises part of a ventricular assist device configured to assist ventricular function of a subject, e.g., a left ventricular assist device configured to assist left ventricular function of a subject. The ventricular assist device typically includes an elongate tube configured to cross the aortic valve of the subject, with a proximal end of the tube positioned within the aorta of the subject and a distal end of the tube positioned within the left ventricle of the subject. The elongate tube includes a frame formed from a self-expanding shape memory alloy and a blood-impermeable material disposed on the frame. The ventricular assist device includes a pump, which typically includes an impeller and a cage disposed around the impeller. The impeller is typically configured to rotate to pump blood out of the subject's left ventricle and into the subject's aorta, and typically also prevents backflow of blood from the aorta into the left ventricle across the aortic valve.

[0006] For some applications, the cage is integrally formed with the elongate tube such that the cage is disposed within the elongate tube at a proximal end of the elongate tube, the pump is thereby disposed within the proximal portion of the elongate tube, and the longitudinal axis of the pump is thereby aligned with the longitudinal axis of the elongate tube. Alternatively, the cage is not integrally formed with the elongate tube.

[0007] Thus, according to some applications of the present invention, there is provided an apparatus, the apparatus comprising: an impeller, the impeller comprising: containing at least one helical elongated element; a spring disposed within and coaxially with the helical elongate element; and It includes a film of material supported between a helical elongate element and a spring.

[0008] In some applications, the impeller includes a plurality of helical elongated elements, and the film of material is supported between the plurality of helical elongated elements and a spring, such that the impeller defines a plurality of blades.

[0009] In some applications, the pitch of the helical elongate element varies along the length of the helical elongate element when the impeller is disposed in a radially unconstrained configuration.

[0010] In some applications, the pitch of the helical elongated elements is greater than 1 mm when the impeller is arranged in a radially unconstrained configuration.

[0011] In some applications, the pitch of the helical elongated elements is less than 20 mm when the impeller is arranged in a radially unconstrained configuration.

[0012] For some applications, the impeller is configured to be positioned within a blood vessel of the subject and to pump blood through the blood vessel of the subject by rotation of the impeller.

[0013] For some applications, the impeller is configured to be placed in the aorta of the subject and to pump blood from the left ventricle of the subject by rotation of the impeller.

[0014] For some applications, the impeller is configured to be placed in a ventricle of a subject's heart and to pump blood from the ventricle by rotation of the impeller.

[0015] For some applications, the impeller is positioned in the aorta of the subject and is configured to prevent backflow of blood from the aorta into the left ventricle of the subject.

[0016] In some applications, the impeller is configured to be radially constrained by an axially stretched helical elongate element and a spring, and in response to the axial extension of the helical elongate element and the spring, the film is configured to change shape without tearing the film of material.

[0017] For some applications, the apparatus further comprises: The subject's aortic valve includes an elongated tube configured to traverse the subject's aortic valve, with a proximal end of the tube positioned within the subject's aorta and a distal end of the tube positioned within the subject's left ventricle, the elongated tube comprising: a frame formed from a shape memory alloy; and a blood impermeable material disposed on the frame; and The apparatus further includes a cage disposed around the impeller; The elongated tube is configured to be disposed around a cage and an impeller, and the impeller is configured to rotate to pump blood from the left ventricle to the aorta.

[0018] For some applications, the spring is configured to stabilize the impeller relative to the elongated tube during rotation of the impeller due to its stiffness when disposed in its radially unconstrained configuration, and ... the stiffness of the spring, and the spring is configured to stabilize the impeller relative to is being maintained.

[0019] Some application examples are: The spring defines a lumen therethrough, and The impeller also: including a proximal bushing and a distal bushing; and The impeller includes a rigid shaft configured to extend from the proximal bushing to the distal bushing through a lumen defined by the spring, the rigid shaft configured to stabilize the impeller relative to the elongate tube during rotation of the impeller such that a gap is maintained between the outer edge of the impeller and the inner surface of the elongate tube.

[0020] In some applications, the cage is integrally formed with the frame of the elongated tube, and the cage is positioned within the frame of the elongated tube at the proximal end of the elongated tube, thereby positioning the impeller within the proximal portion of the elongated tube and aligning the longitudinal axis of the impeller with the longitudinal axis of the elongated tube.

[0021] In some applications, the gap between the outer edge of the impeller and the inner surface of the elongated tube is less than 1 mm.

[0022] In some applications, the gap between the outer edge of the impeller and the inner surface of the elongated tube is less than 0.4 mm.

[0023] In some applications, the impeller is configured to be stable relative to the elongated tube such that a gap between the impeller and the elongated tube is maintained during rotation of the impeller.

[0024] In some embodiments, the cage is not integrally formed with the frame of the elongate tube.

[0025] For some applications, the device further includes one or more support arms configured to extend from the cage to the elongated tube frame and configured to stabilize the distal end of the impeller relative to the elongated tube frame during rotation of the impeller, such that a gap is maintained between the outer edge of the impeller and the inner surface of the elongated tube.

[0026] For some applications, the support arm is configured to be slidable relative to the elongated tube frame.

[0027] For some applications, the support arms are configured to be coupled to a frame of elongated tubes.

[0028] In some applications, the device further includes a plurality of winged projections connected to the elongated tube, the plane defined by the winged projections being parallel to the longitudinal axis of the elongated tube, and the winged projections being configured to stabilize the turbulent blood flow created by the rotation of the impeller by directing the blood flow along the longitudinal axis of the elongated tube.

[0029] For some applications, the elongate tube is configured to be inserted transcatheterically into a body of a subject while in the radially constrained configuration, and the pterygoids are configured to collapse when the elongate tube is in the radially constrained configuration. are.

[0030] In some applications, the spring defines a lumen therethrough and the impeller further comprises: including a proximal bushing and a distal bushing; and It includes a rigid shaft configured to extend from the proximal bushing to the distal bushing through a lumen defined by a spring.

[0031] For some applications, the rigid shaft is configured to maintain the proximal and distal bushings in alignment with one another.

[0032] For some applications, the impeller is configured to be placed within the body of a subject, and following placement of the spring within the body of the subject, the rigid shaft is configured to be placed within the lumen defined by the spring.

[0033] For some applications, the impeller is configured to be placed within the body of the subject, and the rigid shaft is configured to be placed within the lumen defined by the spring during placement of the impeller within the body of the subject.

[0034] For some applications, the impeller further includes a proximal bushing and a distal bushing, and the spring is configured to maintain the proximal bushing and the distal bushing in alignment with one another when disposed in its radially unconstrained configuration due to its stiffness.

[0035] In some applications, the spring is configured such that when disposed in its radially unconstrained configuration, there is substantially no gap between a winding of the spring and an adjacent winding.

[0036] Furthermore, according to some applications of the present invention, there is provided a method, the method comprising: and placing an impeller within a blood vessel of the subject, the impeller comprising: containing at least one helical elongated element; a spring disposed within and coaxially with the helical elongate element; and including a film of material supported between the helical elongated element and the spring; The method includes pumping blood through a blood vessel of a subject with an impeller.

[0037] The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings in which: [Brief explanation of the drawings]

[0038] [Figure 1] 1A and 1B are schematic illustrations of a ventricular assist device positioned in the left ventricle of a subject, in accordance with some applications of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a pump including an impeller and a cage, in accordance with some applications of the present invention. [Figure 3] FIG. 3 is a schematic diagram of a frame of an elongated tube of a ventricular assist device and a cage of an impeller of a ventricular assist device, according to some applications of the present invention. [Figure 4A] 4A and 4B are schematic illustrations of a ventricular assist device, in accordance with some additional applications of the present invention. [Figure 4B] 4A and 4B are schematic illustrations of a ventricular assist device, in accordance with some additional applications of the present invention. [Figure 5A-B] 5A and 5B are schematic illustrations of respective cross-sectional views of the impeller of the ventricular assist device shown in FIGS. 4A and 4B, in accordance with some applications of the present invention. [Figure 5C-D] Figure 5C is a schematic diagram of a cross-sectional view of the ventricular assist device shown in Figures 4A and 4B, and Figure 5D is a schematic diagram of an impeller of the ventricular assist device shown in Figures 4A and 4B in a radially constrained configuration, in accordance with certain applications of the present invention. [Figure 6] 6A and 6B are schematic diagrams of a stator of a ventricular assist device, in accordance with some applications of the present invention. [Figure 7A] 7A, 7B, and 7C are schematic diagrams of a ventricular assist device including a centrifugal pump, in accordance with some applications of the present invention. [Figure 7B-C] 7A, 7B, and 7C are schematic diagrams of a ventricular assist device including a centrifugal pump, in accordance with some applications of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] Detailed Description of the Embodiments Reference is now made to FIGS. 1A and 1B, which are schematic illustrations of a ventricular assist device 20 positioned in a subject's left ventricle 22, in accordance with some applications of the present invention. The ventricular assist device includes an elongated tube 24 that crosses the subject's aortic valve 26, such that a proximal end 28 of the elongated tube is positioned in the subject's aorta 30 and a distal end 32 of the tube is positioned within the left ventricle 22. The elongated tube typically includes a radially expandable frame 34 formed from a self-expanding shape-memory alloy such as Nitinol and a blood-impermeable material 36 disposed on the frame. For example, the blood-impermeable material may include polyurethane, polyester, and / or silicone. Typically, the frame provides the elongated tube with rigidity, and the blood-impermeable material provides the elongated tube with blood impermeability. More typically, the shape-memory alloy of the frame is shape-set such that the frame assumes its tubular shape in the absence of any force applied to the tube. Typically, device 20 is inserted transcatheterically into the left ventricle (e.g., through the brachial artery) while the tube is in a radially constrained state. Upon release from the catheter, the tube automatically assumes its tubular shape due to expansion of the frame. A pump 40 is disposed within the elongated tube (e.g., within a proximal portion of the elongated tube, as shown) and is configured to pump blood through the elongated tube from the left ventricle into the aorta, thereby assisting left ventricular function.

[0040] FIG. 2 is a schematic diagram of a pump 40 according to some applications of the present invention. The pump 40 typically includes a radially expandable impeller 42 disposed within a radially expandable cage 44. Typically, the pump 40 is inserted transcatheterically into the left ventricle while the impeller and cage are in a radially constrained configuration. The impeller and cage typically include a shape-memory alloy (such as Nitinol) whose shape is set so that the impeller and cage assume their radially unconstrained (i.e., radially expanded) configuration in the absence of any radially constraining forces acting on the impeller and cage. Thus, the cage and impeller typically radially expand when released from the distal end of the catheter through which they are inserted. For some applications, an engagement mechanism engages the impeller and cage relative to one another, such that the cage becomes radially constrained in response to the impeller becoming radially constrained, for example, in accordance with the apparatus and methods described in WO 14 / 141284 to Schwammenthal, WO 15 / 177793 to Schwammenthal, and / or WO 16 / 18999 to Schwammenthal, which are incorporated herein by reference. or similar to the blood pumps described in International Publication No. WO 16 / 185473 to Schwammenthal, all of which are incorporated herein by reference. Typically, pump 40 pumps blood from the left ventricle into the aorta through an elongated tube by rotating an impeller. For some applications, a rotating cable 46 (FIG. 1B) rotates the impeller. Typically, the rotating cable is rotated by a motor (not shown) located either outside the subject's body or inside the subject's body.

[0041] For some applications, the pump 40 is disposed at the proximal end of the elongated tube such that the pump is positioned within the aorta, and for some applications, the pump is disposed at the distal end of the elongated tube such that the pump is positioned within a ventricle of the subject.

[0042] Reference is now made to FIG. 3 , which is a schematic diagram of the frame 34 of the elongated tube 24 and the cage 44 of the pump 40 of the ventricular assist device 20, according to some applications of the present invention. As shown, for some applications, the cage is integrally formed with the frame of the elongated tube such that the cage is disposed within the frame of the elongated tube at the proximal end of the elongated tube. Typically, the cage is disposed within the frame of the elongated tube at the proximal end of the elongated tube such that the pump 40 is disposed within the proximal portion of the elongated tube and the longitudinal axis of the pump is aligned with the longitudinal axis of the elongated tube. For some applications, the frame 34 of the elongated tube 24 and the cage 44 are cut from a single piece (e.g., a single tube) of a shape memory material (e.g., a shape memory alloy such as Nitinol). Typically, by virtue of being cut from a single piece of shape memory, the region of the tube in which the cage is placed can be radially compressed to a smaller diameter than would be possible if the cage were cut from a separate piece of shape memory material and inserted inside an elongated tube, and vice versa, all other things being equal.

[0043] Reference is now made to FIG. 4, which is a schematic diagram of a ventricular assist device 20 according to some additional applications of the present invention. For some applications, the pump 40 is generally as shown in FIG. 4A. Typically, the pump includes an impeller 50 including an outer helical elongated element 52 wound around a central axial spring 54, such that the helix defined by the helical elongated element is coaxial with the central axial spring. For some applications, the helical elongated element and the central axial spring are made of a shape memory material (e.g., a shape memory alloy such as Nitinol). Typically, the helical elongated element and the central axial spring support a film 56 of material (e.g., a polymer such as polyurethane and / or silicone) therebetween. The helical elongated element, axial spring, and film define the impeller blades, with the helical elongated element defining the outer edges of the impeller blades (and thereby defining the outer periphery of the impeller), and the axial spring defining the axis of the impeller blades. For some applications, a suture (e.g., polyester suture, not shown) is wrapped around the helical elongate element, as described, for example, in International Publication No. WO 14 / 141284 (incorporated herein by reference). Typically, the suture is configured to promote bonding between a film of material (typically a polymer such as polyurethane or silicone) and the helical elongate element (typically a shape memory alloy such as Nitinol). For some applications, a suture (e.g., polyester suture, not shown) is wrapped around spring 54. Typically, the suture is configured to promote bonding between a film of material (typically a polymer such as polyurethane or silicone) and the spring (typically a shape memory alloy such as Nitinol).

[0044] Typically, the proximal ends of both the spring 54 and the helical elongated element 52 are attached to the impeller. The spring 54 and the helical elongate element 52 are coupled to a proximal bushing (i.e., sleeve bearing) 64 such that the proximal ends of both the spring 54 and the helical elongate element 52 are positioned a similar radial distance from the longitudinal axis of the impeller. Similarly, the distal ends of both the spring 54 and the helical elongate element 52 are typically coupled to a distal bushing 58 of the impeller such that the distal ends of both the spring 54 and the helical elongate element 52 are positioned a similar radial distance from the longitudinal axis of the impeller.

[0045] For some such applications, the frame 34 of the elongated tube 24 does not include a cage integrally formed therewith, as described above with reference to FIG. 3 . Rather, for some such applications, the impeller distal bushing 58 is stabilized relative to the elongated tube by one or more support arms 60 extending radially outward from the impeller distal bushing to the frame 34 of the elongated tube 24. As shown in FIG. 4A , for some applications, the support arms are not connected to the elongated tube frame 34 but are configured to engage the inner surface of the elongated tube, thereby stabilizing the impeller distal bushing relative to the elongated tube. For such applications, the support arms are typically configured to be movable relative to the elongated tube by sliding the support arms along the inner surface of the elongated tube. Alternatively, even if the support arms are not integrally formed with the elongate tube frame 34, they are connected (e.g., by welding, stitching, and / or adhesive) to the elongate tube frame 34 so that they cannot experience movement relative to the elongate tube, at least at the locations where the support arms are connected to the elongate tube frame. Still alternatively, the device includes support arms that are integrally formed with the elongate tube frame 34, as shown in FIG. 4B.

[0046] 4B, which is a schematic illustration of device 20 according to some applications of the present invention, the device includes a support arm 59 integrally formed with frame 34 of elongate tube 24, the support arm being connected to frame 34 at connection point 61. Typically, the support arm is configured to extend from a distal bushing of the impeller to the connection point and thereby stabilize the distal bushing of the impeller relative to the elongate tube.

[0047] With respect to device 20 shown in FIGS. 4A-4B , it is noted that for some applications, impeller 50 is disposed at the proximal end of the elongated tube, as shown, such that during use of device 20, the impeller is disposed within the aorta and rotates within the aorta to pump blood from the ventricle into the left ventricle. It is noted that for some applications (not shown), the impeller is disposed at the distal end of the elongated tube, such that during use of device 20, the impeller is disposed within the ventricle and rotates within the ventricle to pump blood out of the ventricle. Generally, in the context of this application, the term “vessel” should be interpreted to include the ventricle. Similarly, an impeller described as being disposed within a vessel should be interpreted to include an impeller disposed within the ventricle.

[0048] Reference is now made to Figures 5A and 5B, which are schematic illustrations of cross-sections of impeller 50, in accordance with certain applications of the present invention, with Figure 5A being perpendicular to the longitudinal axis of the impeller and Figure 5B being along the longitudinal axis of the impeller. Reference is also made to Figure 5C, which is a schematic illustration of a cross-section of ventricular assist device 20 along the longitudinal axis of the device, in accordance with certain applications of the present invention. As shown, for example, in Figure 5B, spring 54 defines a lumen 62 therethrough. For some applications, a rigid shaft 63 is disposed along the lumen from at least proximal bushing 64 to distal bushing 58 of the impeller. The rigid shaft may provide rotational motion from the proximal bushing to the distal bushing and / or may provide rotational motion to the distal bushing. The spring 54 is configured to maintain the distal and proximal bushings aligned with each other and with the longitudinal axis of the elongate tube. Alternatively or additionally, the spring 54 itself acts as the shaft. Thus, for some applications, the spring is configured to impart rotational motion from the proximal bushing to the distal bushing and / or maintain the distal and proximal bushings aligned with each other and with the longitudinal axis of the elongate tube. For some such applications, the spring is configured such that there is substantially no gap between the windings of the spring and adjacent windings when the spring is disposed in a radially unconstrained configuration.

[0049] Reference is now made to FIG. 5D, which is a schematic illustration of impeller 50 in a radially constrained (i.e., axially elongated) configuration, according to some applications of the present invention. Typically, pump 40 is inserted transcatheterically into the left ventricle while impeller 50 is in its radially constrained configuration. As shown, in the radially constrained configuration, both helical elongated element 52 and central axial spring 54 become axially elongated and radially constrained. Typically, film 56 of material (e.g., silicone) changes shape to accommodate the changing shapes of helical elongated element and axial support spring (both of which support the film of material). Typically, using a spring to support the inner edge of the film allows the film to change shape without tearing or collapsing inward onto a shaft disposed within lumen 62, due to the spring providing a large surface area for the inner edge of the film to bond to. For some applications, using a spring to support the inner edge of the film reduces the diameter against which the impeller can be radially constrained, compared to, for example, when a rigid shaft is used to support the inner edge of the film, because the spring diameter itself can be reduced by axially stretching the spring. As described above and shown in FIG. 5C , a rigid shaft 63 is positioned along lumen 62 (defined along spring 54) from at least proximal bushing 64 to distal bushing 58 of the impeller. For some applications, the rigid shaft is positioned within the lumen even during transcatheter insertion of the impeller into the subject's left ventricle. Alternatively, once the impeller is released from the insertion catheter, the rigid shaft is advanced into lumen 62 and positioned within the subject's ventricle.

[0050] Referring again to FIG. 5A , typically, a gap G exists between the outer edge of the impeller and the inner surface of the elongated tube 24, even at the location where the overall length of the impeller is at its maximum. For some applications, it is desirable for the gap between the outer edge of the impeller blades and the elongated tube 24 to be relatively small so that the impeller effectively pumps blood from the subject's left ventricle into the subject's aorta. However, it is also desirable to maintain a gap between the outer edge of the impeller blades and the elongated tube 24, for example, to reduce the risk of hemolysis. For some applications, the gap G between the outer edge of the impeller and the inner surface of the elongated tube at the location where the overall length of the impeller is at its maximum is greater than 0.05 mm (e.g., greater than 0.1 mm) and / or less than 1 mm (e.g., less than 0.4 mm), e.g., between 0.05 mm and 1 mm or between 0.1 mm and 0.4 mm. As noted above, for some applications, the impeller distal bushing 58 is stabilized relative to the elongated tube by one or more support arms 60 or 59. For some applications, stabilizing the impeller distal bushing 58 relative to the elongated tube maintains a relatively small gap (i.e., as described above) between the outer edges of the impeller blades and the elongated tube 24 during rotation of the impeller. Alternatively or additionally, a rigid shaft is inserted along the axis of the impeller through the lumen 62 defined by the spring 54, and the rigid shaft stabilizes the impeller distal bushing 58 relative to the elongated tube, maintaining a relatively small gap (i.e., as described above) between the outer edges of the impeller blades and the elongated tube 24 during rotation of the impeller. This is maintained during rotation.

[0051] Typically, the pitch of the helical elongate element 52 is greater than 1 mm (e.g., greater than 6 mm) and / or less than 20 mm (e.g., less than 10 mm) when the impeller 50 is in a radially unconstrained configuration (e.g., inside the subject's ventricle). Typically, other things being equal, the greater the pitch of the helical elongate element (and thus the impeller blades), the greater the blood flow produced by the impeller. Thus, as described, the pitch of the helical elongate element 52 is typically greater than 1 mm (e.g., greater than 6 mm) when the impeller 50 is in a radially unconstrained configuration. On the other hand, it is typically desirable for the impeller to occlude backflow from the subject's aorta into the subject's left ventricle during diastole. Other things being equal, the smaller the pitch of the helical elongate element (and thus the impeller blades), the greater the occlusion provided by the impeller. Thus, as described, the pitch of the helical elongated element 52 is typically less than 20 mm (e.g., less than 10 mm) when the impeller 50 is in a radially unconstrained configuration.

[0052] For some applications, the pitch of the helical elongate element (and thus the impeller blades) varies along the length of the helical elongate element, at least when the impeller is in a radially unconstrained configuration. Typically, for such applications, the pitch increases from the distal end of the impeller (i.e., the end inserted further into the subject's body and disposed upstream relative to the direction of antegrade blood flow) to the proximal end of the impeller (i.e., the end disposed downstream relative to the direction of antegrade blood flow), such that the pitch increases in the direction of blood flow. Typically, blood flow velocity increases along the impeller along the direction of blood flow. Thus, the pitch increases along the direction of blood flow, further accelerating the blood.

[0053] For some applications (not shown), the impeller 50 is generally as shown in FIGS. 4A-5D, except that the impeller includes a plurality of helical elongated elements. For example, the impeller may include two or three helical elongated elements. Typically, a film of material is supported between the plurality of helical elongated elements and a spring, such that the impeller defines a plurality of blades. Typically, the number of blades on the impeller corresponds to the number of helical elongated elements disposed thereon, as generally described, for example, in International Publication No. 14 / 141284 to Schwammenthal (incorporated herein by reference).

[0054] Reference is now made to FIGS. 6A and 6B, which are schematic illustrations of a stator 65 of a ventricular assist device 20 according to some applications of the present invention. For illustrative purposes, FIG. 6B shows the stator in the absence of certain other elements of the ventricular assist device. For some applications, as shown, the stator 65 is disposed within a proximal portion of the frame 34 of the elongated tube 24. Typically, the stator includes a plurality of (e.g., more than two and / or fewer than eight) wing-like projections 66 that extend from the frame 34 when the device 20 is radially unconstrained and are made of a flexible material (e.g., a polymer such as polyurethane and / or silicone). The wing-like projections are typically configured to define a plane that is parallel to the longitudinal axis of the elongated tube, thereby stabilizing the turbulent blood flow created by the impeller by directing blood flow along the longitudinal axis of the elongated tube.

[0055] As shown in FIG. 6A, typically, the elongated tube 24 is It is noted that the elongated tube includes a blood-impermeable material 36 disposed on the membrane 34. For example, the blood-impermeable material may include polyurethane, polyester, or silicone, as described above. It is noted that typically, the elongated tube includes a blood-impermeable material, even though for purposes of illustration, the blood-impermeable material of the tube is not shown in all figures herein.

[0056] As shown in FIG. 6B , for some applications, in accordance with the techniques described above, sutures 68 are wrapped around the frame 34 to facilitate connection between the winglets and the frame 34. For some applications, the winglets extend from the frame 34 to axial support elements 69. Typically, the axial support elements are tubular elements formed of metal, plastic, and / or polymer (polyurethane and / or silicone). For some applications, a stator 65 is integrally formed with the frame 34 of the elongated tube 24. Alternatively or additionally, the stator is formed separately from the elongated tube.

[0057] As described above, device 20 is typically inserted transcatheterically into a subject's ventricle while elongate tube 24 is in a radially constrained state. Upon release from the catheter, the tube automatically assumes its tubular shape due to the self-expanding frame 34 of elongate tube 24. Typically, a stator is inserted into the subject's left ventricle inside the elongate tube. During insertion, the stator's wings are in a collapsed state and do not substantially increase the minimum diameter against which the elongate tube can be radially constrained compared to if the tube did not contain the wings. As elongate tube frame 34 expands, the wings are configured to automatically assume their spread-wing configuration due to the wings being coupled to frame 34.

[0058] 1A and 1B show ventricular assist device 20 in the left ventricle of a subject, it is noted that for some applications, device 20 is placed within the right ventricle of a subject, the device crosses the pulmonary valve, and the techniques described herein are applied mutatis mutandis. Alternatively or additionally, device 20 and / or a portion thereof (e.g., impeller 50 (even in the absence of elongated tube 24)) may be placed within a different portion of the subject's body to assist in pumping blood from such portion. For example, device 20 and / or a portion thereof (e.g., impeller 50 (even in the absence of elongated tube 24)) may be placed in a blood vessel and used to pump blood through the blood vessel. For some applications, device 20 and / or portions thereof (e.g., impeller 50 (even in the absence of elongated tube 24)) is configured, mutatis mutandis, to be placed within the subclavian artery or jugular vein at the junction of the vein and lymphatic vessel, and used to increase the flow of lymph fluid from the lymphatic vessel into the vein.

[0059] Reference is now made to Figure 7A, which is a schematic illustration of a ventricular assist device 70 including a centrifugal pump 72, in accordance with certain applications of the present invention. Reference is also made to Figures 7B and 7C, which show three-dimensional and two-dimensional cross-sectional views, respectively, of a centrifugal pump, in accordance with certain applications of the present invention.

[0060] For some applications, the ventricular assist device assists the pumping of a ventricle (e.g., left ventricle 22) by using a centrifugal pump to pump blood from the subject's left ventricle, out of the subject's body, and into the subject's aorta 30. For some applications, a catheter 74 is inserted into the subject's vasculature extending from the centrifugal pump 72 to the subject's ventricle. As shown in Figures 7B and 7C, typically, the catheter Catheter 74 defines concentric tubes 76 and 78. Blood is pumped out of the subject's left ventricle through a first of the concentric tubes (e.g., inner tube 76, shown by the dashed arrow indicating the direction of blood flow in FIG. 7C), and blood is pumped through a second of the concentric tubes (e.g., outer tube 78 in FIG. 7C) into the subject's aorta. Typically, the first and second tubes are inserted into the subject's body via a single insertion point (e.g., femoral artery 80, as shown in FIG. 7A) or through different insertion points (such as the subclavian artery). For some applications, centrifugal pump 72 defines an additional tube 82 (by which blood pressure is measured).

[0061] The scope of the present invention includes combinations of any of the devices and methods described herein with any of the devices and methods described in one or more of the following applications, all of which are incorporated herein by reference:

[0062] International Patent Application No. PCT / IL2017 / 051092, filed September 28, 2017, to Tuval, entitled "Blood vessel tube," which claims priority from U.S. Provisional Patent Application No. 62 / 401,403, filed September 29, 2016, to Tuval;

[0063] International Patent Application No. PCT / IL2016 / 050525, entitled "Blood Pump," filed May 18, 2016, to Schwammenthal (published as WO 16 / 185473), which claims priority from U.S. Provisional Patent Application No. 62 / 162,881, filed May 18, 2015, to Schwammenthal, entitled "Blood Pump";

[0064] International Patent Application No. PCT / IL2015 / 050532, entitled "Blood Pump," filed May 19, 2015, to Schwammenthal (published as WO 15 / 177793), which claims priority from U.S. Provisional Patent Application No. 62 / 000,192, filed May 19, 2014, to Schwammenthal, entitled "Blood Pump";

[0065] International Patent Application No. PCT / IL2014 / 050289, entitled "Renal Pump," filed March 13, 2014 (published as WO 14 / 141284), to Schwammenthal, which claims priority from (a) U.S. Provisional Patent Application No. 61 / 779,803, filed March 13, 2013, to Schwammenthal, entitled "Renal Pump," and (b) U.S. Provisional Patent Application No. 61 / 914,475, filed December 11, 2013, to Schwammenthal, entitled "Renal Pump";

[0066] U.S. Patent Application No. 14 / 567,439, entitled "Curved catheter," filed December 11, 2014, to Tuval (published as U.S. Patent Application Publication No. 2015 / 0157777), which claims priority from U.S. Provisional Patent Application No. 61 / 914,470, entitled "Curved catheter," filed December 11, 2013, to Tuval; and

[0067] International Patent Application No. PCT / IL2013 / 050495, entitled "Prosthetic Renal Valve," filed June 6, 2013, to Tuval (published as WO 13 / 183060), which claims priority from U.S. Provisional Patent Application No. 61 / 656,244, filed June 6, 2012, to Tuval, entitled "Prosthetic Renal Valve."

[0068] Thus, according to some applications of the present invention, the following inventive concepts are provided:

[0069] Inventive Concept 1. An apparatus comprising: a left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising: an elongated tube configured to traverse an aortic valve of a subject, with a proximal end of the tube positioned within the aorta of the subject and a distal end of the tube positioned within a left ventricle of the subject, the elongated tube comprising: a frame formed from a shape memory alloy; a blood impermeable material disposed on the frame; the left ventricular assist device having a rotatable impeller configured to rotate to pump blood from the left ventricle of the subject to an aorta of the subject; and The left ventricular assist device has a plurality of wing-like protrusions connected to an elongated tube such that a plane defined by the wing-like protrusions is parallel to a longitudinal axis of the elongated tube, and the wing-like protrusions are configured to stabilize turbulent blood flow created by rotation of the impeller by directing blood flow along the longitudinal axis of the elongated tube. The device.

[0070] Inventive Concept 2. The device of Inventive Concept 1, wherein the elongate tube is configured to be inserted transcatheterically into a body of a subject while in a radially constrained configuration, and wherein the pterygoids are configured to collapse when the elongate tube is in its radially constrained configuration.

[0071] Inventive concept 3. A method comprising: placing an elongated tube within a body of a subject such that the elongated tube crosses an aortic valve of the subject, with a proximal end of the tube positioned within the aorta of the subject and a distal end of the tube positioned within a left ventricle of the subject, the elongated tube comprising: a frame formed from a shape memory alloy; a blood impermeable material disposed on the frame; and The method includes pumping blood from a left ventricle of the subject to an aorta of the subject by rotating an impeller disposed within an elongated tube; A plurality of wing-like protrusions are coupled to the elongate tube such that a plane defined by the wing-like protrusions is parallel to a longitudinal axis of the elongate tube, and the wing-like protrusions are configured to stabilize turbulent blood flow created by rotation of the impeller by directing blood flow along the longitudinal axis of the elongate tube. The method.

[0072] Inventive concept 4. The method of inventive concept 3, wherein placing the elongated tube within the body of the subject comprises transcatheterically placing the elongated tube within the body of the subject while the elongated tube is in a radially constrained configuration, and the pterygoids are configured to collapse when the elongated tube is in its radially constrained configuration.

[0073] Inventive concept 5. An apparatus comprising: a left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising: an elongated tube configured to traverse an aortic valve of a subject, with a proximal end of the tube positioned within the aorta of the subject and a distal end of the tube positioned within a left ventricle of the subject, the elongated tube comprising: a frame formed from a shape memory alloy; a blood impermeable material disposed on the frame; and The left ventricular assist device includes a pump having a rotatable impeller and a cage disposed around the rotatable impeller; the cage is integrally formed with the elongated tube, the cage being disposed within the frame of the elongated tube at the proximal end of the elongated tube, and the pump being thereby disposed within the proximal portion of the elongated tube such that the longitudinal axis of the pump is thereby aligned with the longitudinal axis of the elongated tube; The device.

[0074] Inventive concept 6. A method comprising: placing within a body of a subject a left ventricular assist device configured to assist left ventricular function of the subject, the left ventricular assist device comprising: The catheter includes an elongated tube configured to traverse an aortic valve of a subject, such that a proximal end of the tube is positioned within the aorta of the subject and a distal end of the tube is positioned within a left ventricle of the subject, the elongated tube comprising: a frame formed from a shape memory alloy; a blood impermeable material disposed on the frame; The left ventricular assist device includes a pump having a rotatable impeller and a cage disposed about the rotatable impeller; the cage is integrally formed with the elongated tube, the cage being disposed within a frame of the elongated tube at a proximal end of the elongated tube, the pump thereby being disposed within the proximal portion of the elongated tube such that the longitudinal axis of the pump is thereby aligned with the longitudinal axis of the elongated tube; and The method includes pumping blood from a left ventricle of the subject into an aorta of the subject by rotating an impeller; The method,

[0075] Inventive Concept 7. A blood pump for pumping blood from a first location in a body of a subject to a second location in the body of the subject, the blood pump comprising: having a first tube for pumping blood away from the first location; a second tube for pumping blood toward a second location, the first and second tubes being coaxial with one another; and a centrifugal pump configured to pump blood through the first and second tubes; The blood pump.

[0076] Inventive concept 8. A method comprising: pumping blood from a first location in the subject's body to a second location in the subject's body, the pumping comprising: by pumping blood through a first tube and away from a first location; by pumping blood through a second tube toward a second location, the first and second tubes being coaxial with one another; and by pumping blood through the first and second tubes using a centrifugal pump; The method.

[0077] It will be appreciated by those skilled in the art that the present invention is not limited to what has been specifically shown and described above, but rather the scope of the present invention includes both combinations and subcombinations of the various features described above, as well as variations and modifications thereof that would occur to one skilled in the art upon reading the above description and that are not in the prior art.

Claims

1. 1. An apparatus, comprising: an impeller comprising: having at least one helical elongated element; a spring disposed within and coaxially with said helical elongate element; and a film of material supported between said helical elongate element and said spring; The device.

2. 2. The apparatus of claim 1, wherein the impeller has a plurality of helical elongated elements, and the film of material is supported between the plurality of helical elongated elements and the spring, such that the impeller defines a plurality of blades.

3. 10. The apparatus of claim 1, wherein the impeller is arranged in a radially unconstrained configuration and the pitch of the helical elongated element varies along the length of the helical elongated element.

4. 10. The apparatus of claim 1, wherein the pitch of the helical elongated element is greater than 1 mm when the impeller is disposed in a radially unconstrained configuration.

5. 10. The apparatus of claim 1, wherein the pitch of the helical elongated element is less than 20 mm when the impeller is disposed in a radially unconstrained configuration.

6. 10. The device of claim 1, wherein the impeller is configured to be positioned within a blood vessel of a subject and to pump blood through the blood vessel of the subject by rotation of the impeller.

7. 10. The device of claim 1, wherein the impeller is configured to be positioned in the aorta of a subject and to pump blood from a left ventricle of the subject by rotation of the impeller.

8. 10. The device of claim 1, wherein the impeller is configured to be positioned in a ventricle of a subject and to pump blood from the ventricle by rotation of the impeller.

9. 10. The device of claim 1, wherein the impeller is configured to be placed in an aorta of a subject and to prevent backflow of blood from the aorta into a left ventricle of the subject.

10. 2. The apparatus of claim 1, wherein the impeller is configured to be radially constrained by the axially stretched helical elongate element and the spring, and wherein the film is configured to change shape in response to axial extension of the helical elongate element and the spring without tearing the film of material.

11. 11. The apparatus of any one of claims 1 to 10, further comprising an elongated tube configured to traverse an aortic valve of a subject, such that a proximal end of the tube is positioned within the aorta of the subject and a distal end of the tube is positioned within a left ventricle of the subject, the elongated tube comprising: a frame formed from a shape memory alloy; a blood impermeable material disposed on the frame; and The apparatus further includes a cage disposed around the impeller; the elongated tube is configured to be disposed around the cage and the impeller, and the impeller is configured to rotate to pump blood from the left ventricle to the aorta. The device.

12. 12. The apparatus of claim 11, wherein the spring, when disposed in its radially unconstrained configuration, is configured to stabilize the impeller relative to the elongated tube during rotation of the impeller due to its stiffness, such that a gap is maintained between an outer edge of the impeller and an inner surface of the elongated tube.

13. the spring defining a lumen therethrough; The impeller further comprises: having a proximal bushing and a distal bushing; and a rigid shaft configured to extend through the lumen defined by the spring from the proximal bushing to the distal bushing, the rigid shaft configured to stabilize the impeller relative to the elongated tube during rotation of the impeller such that a gap is maintained between an outer edge of the impeller and an inner surface of the elongated tube; 12. The apparatus of claim 11.

14. 12. The device of claim 11, wherein the cage is integrally formed with the frame of the elongated tube, the cage is positioned within the frame of the elongated tube at the proximal end of the elongated tube, the impeller is thereby positioned within the proximal portion of the elongated tube, and the longitudinal axis of the impeller is thereby aligned with the longitudinal axis of the elongated tube.

15. 12. The apparatus of claim 11, wherein the gap between the outer edge of the impeller and the inner surface of the elongated tube is less than 1 mm.

16. 16. The apparatus of claim 15, wherein the gap between the outer edge of the impeller and the inner surface of the elongated tube is less than 0.4 mm.

17. 16. The apparatus of claim 15, wherein the impeller is configured to be stable relative to the elongated tube such that the gap between the impeller and the elongated tube is maintained during rotation of the impeller.

18. 12. The device of claim 11, wherein the cage is not integrally formed with the frame of the elongated tube.

19. 20. The apparatus of claim 18, further comprising one or more support arms configured to extend from the cage to the frame of the elongated tube and configured to stabilize a distal end of the impeller relative to the frame of the elongated tube during rotation of the impeller, such that a gap is maintained between an outer edge of the impeller and an inner surface of the elongated tube.

20. 20. The apparatus of claim 19, wherein the support arm is configured to be slidable relative to the frame of the elongate tube.

21. The support arm is configured to be coupled to the frame of the elongated tube.

20. The device of claim 19.

22. 12. The device of claim 11, further comprising a plurality of wing-like protrusions connected to the elongate tube, the plane defined by the wing-like protrusions being parallel to the longitudinal axis of the elongate tube, the wing-like protrusions being configured to stabilize blood turbulence created by rotation of the impeller by directing blood flow along the longitudinal axis of the elongate tube.

23. 23. The device of claim 22, wherein the elongated tube is configured to be inserted transcatheterically into the body of the subject while in a radially constrained configuration, and the pterygoids are configured to collapse when the elongated tube is in its radially constrained configuration.

24. The spring defines a lumen therethrough, and the impeller further comprises: a proximal bushing and a distal bushing; and a rigid shaft configured to extend from the proximal bushing to the distal bushing through the lumen defined by the spring; An apparatus according to any one of claims 1 to 10.

25. 25. The device of claim 24, wherein the rigid shaft is configured to maintain the proximal and distal bushings aligned with one another.

26. 25. The device of claim 24, wherein the impeller is configured to be placed within a body of a subject, and wherein the rigid shaft is configured to be placed within the lumen defined by the spring following placement of the spring within the body of the subject.

27. 25. The device of claim 24, wherein the impeller is configured to be placed within a body of a subject, and the rigid shaft is configured to be placed within the lumen defined by the spring during placement of the impeller within the body of the subject.

28. 11. The device of claim 1, wherein the impeller further comprises a proximal bushing and a distal bushing, and wherein the spring is configured to maintain the proximal and distal bushings aligned with one another due to its stiffness when disposed in its radially unconstrained configuration.

29. 29. The apparatus of claim 28, wherein the spring is configured such that when disposed in its radially unconstrained configuration, there is substantially no gap between a winding of the spring and an adjacent winding.

30. 1. A method, comprising: placing an impeller in a blood vessel of the subject, the impeller comprising: having at least one helical elongated element; a spring disposed within and coaxially with said helical elongate element; and a film of material supported between said helical elongate element and said spring; The method includes pumping blood through a blood vessel of the subject with the impeller. The method.

31. 31. The method of claim 30, wherein placing the impeller within the blood vessel of the subject comprises placing the impeller within the blood vessel of the subject such that the impeller has a plurality of helical elongate elements, and the film of material is supported between the plurality of helical elongate elements and the spring, and the impeller defines a plurality of blades.

32. 31. The method of claim 30, wherein placing the impeller within the blood vessel of the subject comprises placing the impeller within the blood vessel of the subject such that the pitch of the helical elongate element varies along the length of the helical elongate element when the impeller is placed within the blood vessel.

33. 31. The method of claim 30, wherein placing the impeller within the blood vessel of the subject comprises placing the impeller within the blood vessel of the subject such that the pitch of the helical elongate element is greater than 1 mm when the impeller is placed inside the blood vessel.

34. 31. The method of claim 30, wherein placing the impeller within the blood vessel of the subject comprises placing the impeller within the blood vessel of the subject such that the pitch of the helical elongate element is less than 20 mm when the impeller is placed inside the blood vessel.

35. 31. The method of claim 30, wherein placing the impeller in the subject's blood vessel comprises placing the impeller in the subject's aorta, and pumping blood through the subject's blood vessel comprises pumping blood from the subject's ventricle into the aorta.

36. 31. The method of claim 30, wherein placing the impeller in a blood vessel of the subject comprises placing the impeller in a ventricle of the subject, and pumping blood through the blood vessel of the subject comprises pumping blood from a ventricle of the subject.

37. 31. The method of claim 30, wherein placing the impeller in the subject's blood vessel comprises placing the impeller in the subject's aorta, and pumping blood through the subject's blood vessel comprises using the impeller to prevent backflow of blood from the subject's aorta into the subject's left ventricle.

38. 31. The method of claim 30, wherein placing the impeller within the blood vessel comprises transcatheterically inserting the impeller into the blood vessel of the subject by axially stretching the helical elongate element and the spring, thereby causing the film of material to change shape without tearing the film of material.

39. further comprising placing an elongated tube within the body of the subject such that the elongated tube traverses the aortic valve of the subject, the proximal end of the tube being positioned within the aorta of the subject and the distal end of the tube being positioned within the left ventricle of the subject, the elongated tube comprising: a frame formed from a shape memory alloy; and a blood impermeable material disposed on the frame; Placing the impeller in the blood vessel comprises placing the impeller in an aorta of the subject, the impeller being disposed within a cage, and the cage the impeller and the rotor are disposed within the elongated tube; and pumping blood through the blood vessels of the subject with the impeller comprises pumping blood from the left ventricle to the aorta.

39. The method according to any one of claims 30 to 38.

40. 40. The method of claim 39, wherein rotating the impeller comprises stabilizing the impeller relative to the elongated tube using the stiffness of the spring during rotation of the impeller, such that a gap is maintained between an outer edge of the impeller and an inner surface of the elongated tube.

41. Disposing the impeller within the blood vessel further comprises: having a proximal bushing and a distal bushing; and a rigid shaft configured to extend from the proximal bushing to the distal bushing through a lumen defined by the spring, the rigid shaft configured to stabilize the impeller relative to the elongate tube during rotation of the impeller; and positioning the impeller within the blood vessel such that a gap is maintained between an outer edge of the impeller and an inner surface of the elongate tube.

40. The method of claim 39.

42. 40. The method of claim 39, wherein placing the impeller within the aorta of the subject comprises placing the impeller within the aorta of the subject such that the cage is integrally formed with the frame of the elongated tube, the cage is disposed within the frame of the elongated tube at the proximal end of the elongated tube, the impeller is thereby disposed within the proximal portion of the elongated tube, and the longitudinal axis of the impeller is thereby aligned with the longitudinal axis of the elongated tube.

43. 40. The method of claim 39, wherein positioning the impeller within the aorta of the subject comprises positioning the impeller within the aorta of the subject such that a gap between an outer edge of the impeller and an inner surface of the elongate tube is less than 1 mm.

44. 44. The method of claim 43, wherein positioning the impeller within the aorta of the subject comprises positioning the impeller within the aorta of the subject such that the gap between the outer edge of the impeller and the inner surface of the elongate tube is less than 0.4 mm.

45. 40. The method of claim 39, wherein positioning the impeller within the aorta of the subject comprises positioning the impeller within the aorta of the subject such that the impeller is stabilized relative to the elongated tube, such that the gap between the impeller and the elongated tube is maintained during rotation of the impeller.

46. 40. The method of claim 39, wherein placing the impeller within the aorta of the subject comprises placing the impeller within the aorta of the subject such that the cage is not integrally formed with the frame of the elongated tube.

47. 47. The method of claim 46, wherein positioning the impeller within the aorta of the subject comprises one or more support arms configured to extend from the cage to the frame of the elongated tube and configured to stabilize a distal end of the impeller relative to the frame of the elongated tube during rotation of the impeller, and positioning the impeller within the aorta of the subject such that a gap is maintained between an outer edge of the impeller and an inner surface of the elongated tube.

48. 48. The method of claim 47, wherein placing the impeller within the aorta of the subject comprises placing the impeller within the aorta of the subject in a manner such that the support arm is configured to be slidable relative to the frame of the elongated tube.

49. 48. The method of claim 47, wherein placing the impeller within the aorta of the subject comprises placing the impeller within the aorta of the subject with the support arm coupled to the frame of the elongated tube.

50. 40. The method of claim 39, wherein placing the elongated tube within the body of the subject comprises placing the elongated tube within the body of the subject in a manner such that a plurality of wing-like protrusions coupled to the elongated tube are configured such that a plane defined by the wing-like protrusions is parallel to a longitudinal axis of the elongated tube, the wing-like protrusions directing blood flow along the direction of the longitudinal axis of the elongated tube, thereby stabilizing blood turbulence created by rotation of the impeller.

51. 51. The method of claim 50, wherein placing the elongated tube within the body of the subject comprises transcatheterically placing the elongated tube within the body of the subject while the elongated tube is in a radially constrained configuration, and wherein the pterygoids are configured to collapse when the elongated tube is in its radially constrained configuration.

52. Disposing the impeller within the blood vessel further comprises: having a proximal bushing and a distal bushing; and disposing the impeller within the blood vessel with a rigid shaft configured to extend through a lumen defined by the spring from the proximal bushing to the distal bushing.

39. The method according to any one of claims 30 to 38.

53. 53. The method of claim 52, wherein rotating the impeller comprises using the rigid shaft to maintain the proximal and distal bushings aligned with one another during rotation of the impeller.

54. 53. The method of claim 52, wherein placing the impeller within the blood vessel comprises placing the spring within the blood vessel, and subsequent to placing the spring within the blood vessel, placing the rigid shaft within the lumen defined by the spring.

55. 53. The method of claim 52, wherein placing the impeller within the blood vessel comprises placing the impeller within the blood vessel while the rigid shaft is disposed within the lumen defined by the spring.

56. 39. The method of claims 30-38, wherein the impeller has a proximal bushing and a distal bushing, and rotating the impeller comprises using stiffness of the spring to maintain the proximal bushing and the distal bushing aligned with one another during rotation of the impeller.

57. 57. The method of claim 56, wherein positioning the impeller within the blood vessel comprises positioning the impeller within the blood vessel such that there is substantially no gap between a winding of the spring and an adjacent winding.

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