ventricular assist device

Abstract

The present application relates to a ventricular assist device. Apparatus and methods are described that include a left ventricular assist device comprising an impeller (50) and a frame (34) disposed about the impeller (50). The frame (34) includes a strut joint (33) at a proximal end of the frame, the strut joint (33) being configured to remain in an open state during assembly of the left ventricular assist device to facilitate insertion of the impeller (50) into the frame (34). After the impeller (50) is inserted into the frame (34), a fixing element (117) maintains the strut joint in a closed state. A pump outlet tube (24) extends to a distal end of the frame (34) and defines one or more lateral blood inlet openings (108) configured to allow blood to flow from the left ventricle of a subject into the pump outlet tube (24). Other applications are also described.

Description

[0001] This application is a divisional application of the application with application date of March 7, 2022, application number 202280006309.4, and invention name “Ventricular Assist Device”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority from the following applications:

[0004] Tuval, U.S. Provisional Patent Application No. 63 / 158,708, filed on March 9, 2021, entitled “Ventricular assist device,” and

[0005] Tuval, U.S. Provisional Patent Application 63 / 254,321, entitled “Ventricular assist device,” filed on October 11, 2021,

[0006] Both U.S. provisional applications are incorporated herein by reference.

[0007] Field of Embodiments of the Invention

[0008] Some applications of the present invention generally relate to medical devices. In particular, some applications of the present invention relate to ventricular assist devices and methods of using the same. background

[0009] A ventricular assist device is a mechanical circulatory support device designed to assist and unload the heart chambers to maintain or increase cardiac output. They are used in patients with heart failure and in patients at risk of worsening heart function during percutaneous coronary intervention. Most commonly, a left ventricular assist device is used in defective hearts to assist the left ventricle. In some cases, a right ventricular assist device is used to assist the right ventricle. Such ventricular assist devices are designed to be permanently implanted or mounted on a catheter for temporary placement.

[0010] Overview of the Embodiments

[0011] According to some applications of the present invention, a left ventricular assist device includes an impeller and a frame disposed about the impeller. The frame includes a strut joint at a proximal end of the frame. The strut joint is configured to remain in an open state during assembly of the left ventricular assist device to facilitate insertion of the impeller into the frame. After the impeller is inserted into the frame, a securing element maintains the strut joint in a closed state. A pump outlet tube extends to the distal end of the frame and defines one or more lateral blood inlet openings configured to allow blood to flow from the left ventricle of the subject into the pump outlet tube.

[0012] For some applications (not shown), the pump outlet tube defines two to four lateral blood inlet openings. Typically, for such applications, each blood inlet opening defines an area greater than 20 square millimeters (e.g., greater than 30 square millimeters), and / or less than 60 square millimeters (e.g., less than 50 square millimeters), such as 20-60 square millimeters, or 30-50 square millimeters. Alternatively or additionally, the outlet tube defines a greater number of smaller blood inlet openings 108, such as more than 10 blood inlet openings, more than 50 blood inlet openings, more than 100 blood inlet openings, or more than 150 blood inlet openings, such as 50-100 blood inlet openings, 100-150 blood inlet openings, or 150-200 blood inlet openings. For some applications, the blood inlet openings are sized so as to (a) allow blood to flow into the tube from the subject's left ventricle, and (b) prevent structures from the subject's left ventricle from entering the frame. Typically, for such applications, the distal tapered portion of the pump outlet tube (which defines the blood inlet opening) is constructed to reduce the risk of structures from the left ventricle (e.g., chordae tendineae, pilonidales, and / or papillary muscles) entering the frame and potentially being damaged by the impeller and / or axial shaft and / or causing damage to the left ventricular assist device.

[0013] Typically, the portion of the pump outlet tube that defines the blood inlet opening (e.g., the distal tapered portion of the pump outlet tube) has a porosity (where porosity is defined as the percentage of the area of ​​the portion that is porous for blood flow) greater than 40%, such as greater than 50%, or greater than 60%. Thus, on the one hand, the blood inlet opening is relatively small (to prevent structures of the left ventricle from entering the frame), but on the other hand, the porosity of the portion of the pump outlet tube that defines the blood inlet opening is relatively high to allow sufficient blood to flow into the pump outlet tube.

[0014] For some applications, each blood inlet opening has a circular or polygonal shape. For some applications, each blood inlet opening has a hexagonal shape. Typically, using openings having a hexagonal shape allows the portion of the pump outlet tubing defining the blood inlet openings to have a relatively high porosity (e.g., as described above) while providing sufficient material between the blood inlet openings to prevent tearing and / or stretching of the material.

[0015] For some applications, the width of the gaps between the hexagonal (or other type of polygonal) holes within the proximal region of the distal tapered portion of the pump outlet tube (which typically defines the blood inlet opening) is greater than the width of the gaps between the hexagonal (or other type of polygonal) holes within the distal region of the distal tapered portion of the pump outlet tube. Typically, for such applications, the distance between opposing sides of each hexagon (or other type of polygon) within the proximal region of the distal tapered portion of the pump outlet tube is less than the distance between opposing sides of each hexagon (or other type of polygon) within the distal region of the distal tapered portion of the pump outlet tube. (Typically, such distances also represent the diameter of a circle enclosed by the respective polygons of a given size.) Furthermore, within the distal region of the distal tapered portion of the pump outlet tube, the distal tapered portion of the pump outlet tube typically has a higher porosity than within the proximal region of the distal tapered portion of the pump outlet tube.

[0016] Typically, the pump outlet tube is coupled to the frame by heating. For some applications, in a proximal region of the distal tapered portion of the pump outlet tube, the gaps between the blood inlet holes are wider than the gaps between the blood inlet holes in the distal region, and / or the blood inlet holes are smaller than the blood inlet holes in the distal region, and / or the porosity is lower than the porosity in the distal region, so as to prevent and / or reduce damage (e.g., tearing, thinning, and / or stretching) that may be caused to the material defining the blood inlet holes during the above-mentioned heating process.

[0017] For some applications, the ventricular assist device includes a liner that lines the inside of a frame that houses the impeller. For some applications, the liner is positioned within the frame to provide a smooth inner surface (e.g., a smooth inner surface having a substantially circular cross-sectional shape) through which blood is pumped by the impeller. Typically, by providing a smooth surface, the covering material reduces hemolysis caused by the impeller pumping blood relative to pumping blood between the impeller and the struts of the frame. For some applications, the liner includes polyurethane, polyester, and / or silicone. Alternatively or additionally, the liner includes polyethylene terephthalate (PET) and / or polyether block amide

[0018] Typically, the liner is shaped to form a smooth surface in the overlap region between the liner and the pump outlet tube (e.g., to reduce hemolysis, as described above), and the pump outlet tube is shaped to conform to the struts of the frame. Furthermore, the liner typically has a substantially circular cross-section. For some applications, the pump outlet tube and the liner are coupled to each other in the overlap region between the liner and the pump outlet tube, for example, via vacuum, via an adhesive, and / or using a thermoforming process, as described below.

[0019] For some applications, the pump outlet tube and the liner are bonded to each other and / or to the frame in the following manner. For some applications, the liner is bonded directly to the inner surface of the frame before the pump outlet tube is bonded to the outside of the frame. Note that by bonding the liner directly to the inner surface of the frame (rather than simply bonding the liner to the pump outlet tube, thereby sandwiching the frame between the liner and the pump outlet tube), any bubbles, wrinkles, and other discontinuities in smoothness of the surface provided by the liner are typically avoided. For some applications, initially, the frame is treated to enhance the bond between the liner and the inner surface of the frame. For some applications, the treatment of the frame includes applying a plasma treatment to the frame (e.g., to the inner surface of the frame), immersing the frame in a coupling agent (e.g., a silane solution) having at least two functional groups (the at least two functional groups being configured to bond to the frame and the material from which the liner is made, respectively), and / or immersing the frame in a solution containing the material from which the liner is made (e.g., a polyurethane solution). For some applications, a solution containing the material from which the liner is made (e.g., a polyurethane solution) is then sprayed onto the central cylindrical portion of the cage. Once the inner surface of the frame has been treated, the liner is bonded to the inner surface of the central cylindrical portion of the frame (e.g., bonded to the inner surface of the central cylindrical portion of the frame). Typically, the liner (which is formed into a tube) is placed over the mandrel, the frame is placed over the liner, and pressure is applied through a heat shrink process. Furthermore, the liner and frame assembly is typically heated in an oven.

[0020] After the liner has been bonded to the frame, a portion of the pump outlet pipe is placed around the outside of the frame. Typically, a mandrel is used to heat the frame from the inside. Typically, as the frame is heated, an outer tube (usually made of silicone) applies pressure to the pump outlet pipe, pushing it radially inward so that it conforms to the shape of the frame's struts. For some applications, at this stage, the mandrel placed inside the liner and heating it is shorter than the length of the liner. The mandrel is typically placed within the liner, leaving an excess outside the mandrel at each end of the liner. Typically, the liner acts as a shield to prevent the pump outlet pipe from overheating and damage from the heating of the mandrel. Placing the liner on the mandrel in this manner prevents the mandrel from direct contact with the frame and / or the pump outlet pipe. For some applications, the combination of the frame, liner, and the portion of the pump outlet pipe positioned around the frame is then shaped to the desired shape and size using shaping techniques known in the art.

[0021] Typically, the pump outlet tube (or different types of pump inlet guards) include a coupling portion (e.g., a tubular coupling portion, as shown) extending distally from the pump outlet tube. For some applications, the coupling portion is coupled to a surface distal to the frame to anchor the distal end of the pump outlet tube. For some applications, the coupling portion defines a hole (e.g., toward the distal end of the coupling portion). For some applications, the adhesive is applied between the coupling portion and the surface via the hole. For some applications, the surface is threaded. Typically, the threaded surface allows the adhesive to gradually and evenly diffuse between the coupling portion and the surface. In addition, the coupling portion is typically transparent so that the diffusion of the adhesive is visible through the coupling portion. Therefore, for some applications, once the adhesive has sufficiently diffused between the coupling portion and the surface (e.g., once the surface has been covered with adhesive), the application of the adhesive is terminated.

[0022] For some applications, the ventricular assist device includes a protective braid at its distal end. For some applications, to reduce the risk of structures from the left ventricle (e.g., chordae tendineae, chordae carnosus, and / or papillary muscles) entering the frame and potentially being damaged by the impeller and / or axial shaft and / or causing damage to the left ventricular assist device, the distal tapered portion of the frame is covered with a protective braid (from the inside or outside). Typically, the braid is embedded between the pump outlet tube and the liner within at least a portion of the cylindrical portion of the frame such that during curling of the frame, the braid curls with the pump outlet tube and the liner, thereby preventing the braid from moving relative to the pump outlet tube and / or the liner.

[0023] In general, in the specification and claims of this application, when the term "proximal" and related terms are used with respect to a device or a portion thereof, the term "proximal" and related terms should be interpreted to mean that when the device or a portion thereof is inserted into the body of a subject, the end of the device or a portion thereof is generally closer to the location through which the device is inserted into the body of the subject. When the term "distal" and related terms are used with respect to a device or a portion thereof, the term "distal" and related terms should be interpreted to mean that when the device or a portion thereof is inserted into the body of a subject, the end of the device or a portion thereof is generally farther away from the location through which the device is inserted into the body of the subject.

[0024] The scope of the present invention includes the use of the apparatus and methods described herein in anatomical locations other than the left ventricle and aorta.Thus, a ventricular assist device and / or portions thereof are sometimes referred to herein (in the specification and claims) as a blood pump.

[0025] Therefore, according to some applications of the present invention, there is provided a device comprising:

[0026] A left ventricular assist device, the left ventricular assist device comprising:

[0027] an impeller configured to be placed within the left ventricle of the subject and configured to pump blood from the left ventricle of the subject to the subject's aorta by rotation;

[0028] a frame disposed about the impeller, the frame including a plurality of strut junctions at a proximal end of the frame, the strut junctions being configured to remain in an open position during assembly of the left ventricular assist device to facilitate insertion of the impeller into the frame;

[0029] a securing element configured to retain the strut joint in a closed state after the impeller is inserted into the frame; and

[0030] A pump outlet tube is configured to pass through an aortic valve of the subject such that a proximal portion of the pump outlet tube is disposed within the subject's aorta and a distal portion of the pump outlet tube is disposed within the subject's left ventricle, the distal portion of the pump outlet tube extending to a distal end of the frame and defining one or more lateral blood inlet openings, the one or more lateral blood inlet openings being configured to allow blood to flow from the subject's left ventricle into the pump outlet tube.

[0031] In some applications, the fixation element comprises a ring.

[0032] In some applications, the left ventricular assist device includes a portion distal to the frame, and the pump outlet tube further includes a coupling portion extending distally from the frame and coupled to the portion of the left ventricular assist device distal to the frame.

[0033] In some applications, the distal portion of the pump outlet tube defines more than 10 blood inlet openings that are sized to (a) allow blood to flow from the subject's left ventricle into the tube and (b) prevent structures from the subject's left ventricle from entering the frame. In some applications, the distal portion of the pump outlet tube defines more than 50 blood inlet openings that are sized to (a) allow blood to flow from the subject's left ventricle into the tube and (b) prevent structures from the subject's left ventricle from entering the frame.

[0034] In some applications, a left ventricular assist device further comprises:

[0035] a proximal radial bearing disposed within the proximal bearing housing at the proximal end of the frame;

[0036] a distal radial support disposed within a distal support housing at a distal end of the frame;

[0037] an axial shaft on which the impeller is disposed, the axial shaft passing through the proximal radial support and the distal radial support,

[0038] The fixation element is configured to maintain the strut junction closed about the outer surface of the proximal support housing.

[0039] In some applications, the pump outlet tube further includes a coupling portion extending distally from the frame and coupled to the distal support housing. In some applications, the distal end of the frame is coupled to an outer surface of the distal support housing. In some applications, the left ventricular assist device further includes a distal tip element, and the distal tip element is coupled to the distal support housing.

[0040] In some applications, the outer surface of the proximal bearing housing defines a groove shaped to receive the strut joint. In some applications, the strut joint defines a widened head, and the groove is shaped to conform to the widened head of the strut joint.

[0041] In some applications, the proximal and distal radial supports are made of a ceramic material, and the proximal and distal support housings are made of a second material that can be molded into a desired shape. In some applications, the proximal and distal support housings are made of a metal and / or an alloy. In some applications, the axial shaft comprises a metal and / or an alloy, and the axial shaft is covered with a ceramic sleeve along an area of ​​the axial shaft that contacts either the proximal or distal support during operation of the left ventricular assist device.

[0042] According to some applications of the present invention, there is also provided a method for manufacturing a left ventricular assist device, the method comprising:

[0043] forming the frame such that the frame is closed at a distal end thereof and such that a plurality of strut joints at a proximal end of the frame remain in an open state;

[0044] coupling a pump outlet tube to the frame such that a distal portion of the pump outlet tube extends to a distal end of the frame and defines one or more lateral blood inlet openings, the one or more lateral blood inlet openings being configured to allow blood to flow from the subject's left ventricle into the pump outlet tube, the pump outlet tube being configured to pass through the subject's aortic valve such that a proximal portion of the pump outlet tube is disposed within the subject's aorta and a distal portion of the pump outlet tube is disposed within the subject's left ventricle;

[0045] inserting an impeller into the frame via a proximal end of the frame, the impeller configured to pump blood through the pump outlet tube by rotation; and

[0046] The strut joint at the proximal end of the frame is then closed and the strut joint is maintained in its closed state using a fixation element.

[0047] In some applications, the pump outlet tube further includes a coupling portion configured to extend distally from the frame, and the method further includes coupling the coupling portion to a portion of the left ventricular assist device distal to the frame.

[0048] In some applications, the fixation element includes a ring, and using the fixation element to maintain the strut joint in the closed state of the strut joint includes using the ring to maintain the strut joint in the closed state of the strut joint.

[0049] In some applications, a left ventricular assist device further comprises:

[0050] a proximal radial support disposed within the proximal support housing at the proximal end of the frame;

[0051] a distal radial support disposed within a distal support housing at a distal end of the frame;

[0052] an axial shaft on which the impeller is disposed, the axial shaft passing through the proximal radial support and the distal radial support, and

[0053] Using the fixation element to maintain the strut joint in the closed state of the strut joint includes maintaining the strut joint in the closed state of the strut joint by holding the strut joint closed about an outer surface of the proximal support housing.

[0054] In some applications, the pump outlet tube further comprises a coupling portion configured to extend distally from the frame, and the method further comprises coupling the coupling portion to the distal support housing. In some applications, the method further comprises coupling the distal end of the frame to an outer surface of the distal support housing. In some applications, the method further comprises coupling the distal tip element to the distal support housing.

[0055] In some applications, the outer surface of the proximal support housing defines a recess shaped to receive the strut engagement portion, and retaining the strut engagement portion closed about the outer surface of the proximal support housing includes retaining the strut engagement portion within the recess defined by the outer surface of the proximal support housing. In some applications, the strut engagement portion defines a widened head, and retaining the strut engagement portion within the recess defined by the outer surface of the proximal support housing includes retaining the strut engagement portion within a recess shaped to conform to the widened head of the strut engagement portion.

[0056] In some applications, the proximal and distal radial supports are made of a ceramic material, and the proximal and distal support housings are made of a second material that can be molded into a desired shape. In some applications, the proximal and distal support housings are made of a metal and / or an alloy. In some applications, the axial shaft comprises a metal and / or an alloy, and the method further comprises covering the axial shaft with a ceramic sleeve along an area of ​​the axial shaft that contacts either the proximal or distal support during operation of the left ventricular assist device.

[0057] According to some applications of the present invention, there is further provided a device comprising:

[0058] A left ventricular assist device, the left ventricular assist device comprising:

[0059] an impeller configured to be placed within the left ventricle of the subject and configured to pump blood from the left ventricle of the subject to the subject's aorta by rotation;

[0060] a frame disposed around the impeller; and

[0061] a pump outlet tube configured to pass through the aortic valve of the subject such that a proximal portion of the tube is disposed within the subject's aorta and a distal portion of the pump outlet tube is disposed within the subject's left ventricle,

[0062] a distal portion of the pump outlet tube extending to the distal end of the frame and defining more than ten blood inlet openings sized to (a) permit blood to flow from the subject's left ventricle into the tube and (b) prevent structures from the subject's left ventricle from entering the frame,

[0063] The porosity of the distal portion of the pump outlet tube, defining the blood inlet opening, is lower in a proximal region of the distal portion of the pump outlet tube than in a distal region of the distal portion of the pump outlet tube distal to the proximal region.

[0064] In some applications, each blood inlet opening is shaped such that, in at least one direction, the width of the opening is less than 1 mm.

[0065] In some applications, the ratio of the porosity of the distal portion of the pump outlet tube within the distal region to the porosity of the distal portion of the pump outlet tube within the proximal region is greater than 4:3.

[0066] In some applications, the porosity of the distal portion of the pump outlet tube varies between the proximal and distal regions to induce varying blood flow dynamics at different regions of the distal portion of the pump outlet tube. In some applications, the distal portion of the pump outlet tube is tapered, and the porosity of the distal portion of the pump outlet tube varies between the proximal and distal regions to induce a varying shape of the distal tapered portion along its length.

[0067] In some applications, the pump outlet tube defines a large blood inlet opening along a distal region of the distal portion of the pump outlet tube, and the large blood inlet opening is configured to reduce the risk of thrombosis relative to a smaller blood inlet opening along a distal region of the distal tapered portion of the pump outlet tube.

[0068] In some applications, the distal portion of the pump outlet tube defines more than 50 blood inlet openings that are sized to (a) allow blood to flow from the subject's left ventricle into the tube and (b) prevent structures from the subject's left ventricle from entering the frame.

[0069] In some applications, the blood inlet openings are rectangular and shaped such that the ratio of the length to the width of each blood inlet opening is between 1.1:1 and 4:1. In some applications, the blood inlet openings are rectangular and shaped such that the ratio of the length to the width of each blood inlet opening is between 3:2 and 5:2.

[0070] In some applications, the distal portion of the pump outlet tube has a porosity greater than 40%. In some applications, the distal portion of the pump outlet tube has a porosity greater than 50%. In some applications, the distal portion of the pump outlet tube has a porosity greater than 60%.

[0071] In some applications, the frame defines a central cylindrical portion and a distal tapered portion, the distal portion of the pump outlet tube defining the blood inlet opening is tapered and disposed above the distal tapered portion of the frame, and a portion of the pump outlet tube proximate the distal portion of the pump outlet tube is coupled to the central cylindrical portion of the frame.

[0072] In some applications, a portion of the pump outlet tube proximal to the distal portion of the pump outlet tube is coupled to the central cylindrical portion of the frame by heating, and the porosity in the proximal region of the distal portion of the pump outlet tube is relatively low, such that potential damage to the material defining the blood inlet aperture in the proximal region of the distal portion of the pump outlet tube during heating is reduced relative to a situation where the porosity in the proximal region of the distal portion of the pump outlet tube is relatively high.

[0073] In some applications, the apparatus further includes an inner liner coupled to the inner surface of the central cylindrical portion of the frame such that the inner liner provides a smooth inner surface for the central cylindrical portion of the frame.

[0074] In some applications, the proximal region of the distal portion of the pump outlet tube extends along a length of 0.5 mm to 2 mm.

[0075] In some applications, the blood inlet opening has a polygonal shape. In some applications, the blood inlet opening has a hexagonal shape.

[0076] In some applications, a diameter of a circle enclosed by each blood inlet opening in the proximal region of the distal portion of the pump outlet tube is between 0.1 mm and 0.6 mm. In some applications, a width of a gap between adjacent blood inlet openings in the proximal region of the distal portion of the pump outlet tube is between 0.05 mm and 0.2 mm.

[0077] In some applications, a diameter of a circle enclosed by each blood inlet opening within the distal region of the distal portion of the pump outlet tube is between 0.2 mm and 0.8 mm. In some applications, a width of a gap between adjacent blood inlet openings within the distal region of the distal portion of the pump outlet tube is between 0.01 mm and 0.1 mm.

[0078] In some applications, the ratio of the diameter of a circle enclosed by each blood inlet opening in the distal region of the distal portion of the pump outlet tube to the diameter of a circle enclosed by each blood inlet opening in the proximal region of the distal portion of the pump outlet tube is greater than 7:6. In some applications, the ratio of the width of a gap between adjacent blood inlet openings in the proximal region of the proximal portion of the pump outlet tube to the width of a gap between adjacent blood inlet openings in the distal region of the distal portion of the pump outlet tube is greater than 3:2.

[0079] According to some applications of the present invention, a method is further provided, comprising:

[0080] The housing for the impeller of the blood pump is manufactured by the following steps:

[0081] Treating the frame to enhance the bond between the inner surface of the frame and the lining;

[0082] Thereafter, coupling the liner to the inner surface of the frame along at least a portion of a central cylindrical portion of the frame, the central cylindrical portion of the frame including struts defining a generally cylindrical shape;

[0083] After coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame:

[0084] Place the mandrel inside the liner;

[0085] placing a portion of an elongated tube around at least a portion of the frame, the elongated tube including a proximal portion, the proximal portion of the elongated tube defining at least one blood outlet opening;

[0086] heating the liner, the frame, and the portion of the elongated tube via the mandrel while the portion of the elongated tube is disposed around at least the portion of the frame; and

[0087] While heating the liner, the frame, and the portion of the elongated tube, pressure is applied from outside the portion of the elongated tube to couple the portion of the elongated tube to the frame.

[0088] In some applications, the struts of the central cylindrical portion of the frame define cells, and the cells are configured such that in a non-radially constrained configuration of the frame, the width of each cell within the central cylindrical portion of the frame, as measured around the circumference of the central cylindrical portion of the frame, is less than 2 mm.

[0089] In some applications, applying pressure from outside the portion of the elongated tube while heating the liner, the frame, and the portion of the elongated tube includes conforming the portion of the elongated tube to the structure of the struts of the frame.

[0090] In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner has a substantially circular cross-section. In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner provides a smooth inner surface to the portion of the central cylindrical portion of the frame to which the liner is coupled.

[0091] In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes avoiding bubbles, wrinkles, and other discontinuities in smoothness of the surface presented by the liner.

[0092] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the liner includes applying a plasma treatment to the frame.

[0093] In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes:

[0094] Place the liner over the mandrel;

[0095] placing the frame over the lining; and

[0096] Pressure is applied via a heat shrink process.

[0097] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the liner comprises immersing the frame in a solution comprising a material from which the liner is made. In some applications, the liner comprises polyurethane and immersing the frame in the solution comprises immersing the frame in a polyurethane solution.

[0098] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the inner liner includes spraying the inner surface of the portion of the central cylindrical portion of the frame with a solution comprising a material from which the inner liner is made. In some applications, the inner liner comprises polyurethane and spraying the inner surface of the portion of the central cylindrical portion of the frame includes spraying the inner surface of the portion of the central cylindrical portion of the frame with a polyurethane solution.

[0099] In some applications, after the liner is coupled to the inner surface of the frame along at least the portion of the central cylindrical portion of the frame, a mandrel shorter than the length of the liner is positioned inside the liner. In some applications, after the liner is coupled to the inner surface of the frame along at least the portion of the central cylindrical portion of the frame, positioning the mandrel inside the liner includes positioning the mandrel inside the liner such that excess space is left outside the mandrel at each end of the liner. In some applications, positioning the mandrel inside the liner such that excess space is left outside the mandrel at each end of the liner includes preventing the mandrel from directly contacting the frame or the pump outlet pipe, thereby preventing overheating of the pump outlet pipe and preventing damage to the pump outlet pipe due to heating of the mandrel.

[0100] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the liner includes immersing the frame in a coupling agent having at least two functional groups configured to bond to the frame and the material of the liner, respectively. In some applications, the liner includes polyurethane, and immersing the frame in the coupling agent includes immersing the frame in a silane solution.

[0101] According to some applications of the present invention, a method is further provided, comprising:

[0102] The housing for the impeller of the blood pump is manufactured by the following steps:

[0103] placing the mandrel inside the liner with a central cylindrical portion of a frame disposed about the liner, the central cylindrical portion of the frame including struts defining a generally cylindrical shape,

[0104] The mandrel is shorter than the length of the liner;

[0105] placing a portion of an elongated tube around at least a portion of the frame, the elongated tube including a proximal portion, the proximal portion of the elongated tube defining at least one blood outlet opening;

[0106] heating the liner, the frame, and the portion of the elongated tube via the mandrel while the portion of the elongated tube is disposed around at least the portion of the frame; and

[0107] While heating the liner, the frame, and the portion of the elongated tube, pressure is applied from outside the portion of the elongated tube to couple the portion of the elongated tube to the frame.

[0108] In some applications, the struts of the central cylindrical portion of the frame define cells, and the cells are configured such that in a non-radially constrained configuration of the frame, the width of each cell within the central cylindrical portion of the frame, as measured around the circumference of the central cylindrical portion of the frame, is less than 2 mm.

[0109] In some applications, applying pressure from outside the portion of the elongated tube while heating the liner, the frame, and the portion of the elongated tube includes conforming the portion of the elongated tube to the structure of the struts of the frame.

[0110] In some applications, placing the mandrel inside the liner includes placing the mandrel inside the liner so that excess space is left outside the mandrel at each end of the liner. In some applications, placing the mandrel inside the liner so that excess space is left outside the mandrel at each end of the liner includes preventing the mandrel from directly contacting the frame or the pump outlet pipe, thereby preventing the pump outlet pipe from overheating and preventing damage to the pump outlet pipe due to heating of the mandrel.

[0111] In some applications, the method further comprises, before placing the mandrel within the liner:

[0112] treating the frame to enhance the bond between the inner surface of the frame and the lining; and

[0113] A liner is coupled to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame.

[0114] In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner has a substantially circular cross-section. In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner provides a smooth inner surface to the portion of the central cylindrical portion of the frame to which the liner is coupled.

[0115] In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes avoiding bubbles, wrinkles, and other discontinuities in smoothness of the surface presented by the liner.

[0116] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the liner includes applying a plasma treatment to the frame.

[0117] In some applications, coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes:

[0118] Place the liner over the mandrel;

[0119] placing the frame over the lining; and

[0120] Pressure is applied via a heat shrink process.

[0121] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the liner comprises immersing the frame in a solution comprising a material from which the liner is made. In some applications, the liner comprises polyurethane and immersing the frame in the solution comprises immersing the frame in a polyurethane solution.

[0122] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the inner liner includes spraying the inner surface of the portion of the central cylindrical portion of the frame with a solution comprising a material from which the inner liner is made. In some applications, the inner liner comprises polyurethane and spraying the inner surface of the portion of the central cylindrical portion of the frame includes spraying the inner surface of the portion of the central cylindrical portion of the frame with a polyurethane solution.

[0123] In some applications, treating the frame to enhance the bond between the inner surface of the frame and the liner includes immersing the frame in a coupling agent having at least two functional groups, the at least two functional groups being configured to bond to the frame and the material from which the liner is made, respectively. In some applications, wherein the liner comprises polyurethane, immersing the frame in the coupling agent includes immersing the frame in a silane solution.

[0124] According to some applications of the present invention, there is further provided a device comprising:

[0125] A left ventricular assist device, the left ventricular assist device comprising:

[0126] an impeller configured to be placed within the left ventricle of a subject and configured to pump blood from the left ventricle of the subject to the subject's aorta by rotation;

[0127] a frame disposed about the impeller, the frame defining a distal tapered portion;

[0128] a surface disposed distally of the frame; and

[0129] An inlet guard disposed over the distal tapered portion of the frame, the inlet guard:

[0130] defining a blood inlet opening sized to (a) allow blood to flow from the subject's left ventricle into the tube and (b) prevent structures from the subject's left ventricle from entering the frame, and

[0131] The distal coupling portion is configured to couple to a surface disposed distally of the frame, and the distal coupling portion defines an aperture configured to facilitate application of an adhesive between the distal coupling portion and the surface disposed distally of the frame.

[0132] In some applications, the inlet guard includes a distal portion of a pump outlet tube configured to pass through an aortic valve of the subject such that a proximal portion of the pump outlet tube is disposed within the subject's aorta and a distal portion of the pump outlet tube is disposed within the subject's left ventricle.

[0133] In some applications, the surface disposed on the distal side of the frame is ridged to enhance the bond between the surface and the coupling portion. In some applications, the surface disposed on the distal side of the frame is threaded to allow adhesive to spread gradually and evenly between the coupling portion and the surface.

[0134] In some applications, the coupling portion is tubular.In some applications, the coupling portion is transparent so that the diffusion of the adhesive between the coupling portion and the surface is visible.

[0135] In some applications, a left ventricular assist device further comprises:

[0136] a proximal radial support disposed within the proximal support housing at the proximal end of the frame;

[0137] a distal radial support disposed within a distal support housing at a distal end of the frame;

[0138] an axial shaft on which the impeller is disposed, the axial shaft passing through the proximal radial support and the distal radial support,

[0139] The surface to which the distal coupling portion is coupled includes at least a portion of an outer surface of the distal support housing.

[0140] In some applications, the distal end of the frame is coupled to another portion of the outer surface of the distal support housing. In some applications, the left ventricular assist device further includes a distal tip element, and the distal tip element is coupled to another portion of the outer surface of the distal support housing.

[0141] In some applications, the proximal end of the frame is coupled to an outer surface of the proximal support housing. In some applications, the frame includes a plurality of strut joints at the proximal end of the frame, the strut joints being configured to remain in an open state during assembly of the left ventricular assist device to facilitate insertion of the impeller into the frame, and the proximal end of the frame is coupled to the outer surface of the proximal support housing via a fixation element that holds the strut joints in a closed state around the outer surface of the proximal support housing.

[0142] In some applications, the proximal and distal radial supports are made of a ceramic material, and the proximal and distal support housings are made of a second material that can be molded into a desired shape. In some applications, the proximal and distal support housings are made of a metal and / or an alloy. In some applications, the axial shaft comprises a metal and / or an alloy, and the axial shaft is covered with a ceramic sleeve along an area of ​​the axial shaft that contacts either the proximal or distal support during operation of the left ventricular assist device.

[0143] According to some applications of the present invention, a device is further provided, comprising:

[0144] A ventricular assist device, the ventricular assist device comprising:

[0145] a frame comprising struts defining a plurality of cells, the frame being configured such that in a non-radially constrained configuration of the frame, the frame includes a generally cylindrical central portion;

[0146] a pump outlet tube defining one or more blood outlet openings, a portion of the pump outlet tube disposed outside the frame and coupled to the generally cylindrical central portion of the frame such that the portion of the pump outlet tube conforms to the strut structure of the frame;

[0147] an inner liner coupled to an inner side of the generally cylindrical central portion of the frame to provide a smooth inner surface for the generally cylindrical portion of the frame;

[0148] an impeller at least partially disposed within the generally cylindrical central portion of the frame and configured to pump blood through the tube and out of the one or more blood outlet openings; and

[0149] a protective braid disposed over a distal portion of the frame and configured to prevent structures from the left ventricle of the subject from entering the frame,

[0150] The proximal end of the protective braid is embedded between the pump outlet tube and the liner so that during crimping of the frame, the braid crimps with the pump outlet tube and the liner, thereby preventing movement of the braid relative to the pump outlet tube or the liner.

[0151] In some applications, the braid is woven into the struts of the distal portion of the framework.

[0152] In some applications, the distal portion of the frame is tapered, and the protective braid extends to the end of the distal tapered portion of the frame.

[0153] In some applications, the braid is covered along a distal portion of the distal tapered portion of the frame to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame.

[0154] In some applications, the braid is opened to define large holes within the distal portion of the distal tapered portion of the frame to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame. In some applications, the braid is cut to define large holes within the distal portion of the distal tapered portion of the frame to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame.

[0155] In some applications, a braid is covered along the distal portion of the distal tapered portion of the frame, and the covered braid is cut to define one or more large holes to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame. In some applications, holes are cut from the covered braid around the entire circumference of the frame, such that the covered braid defines holes that extend around the entire circumference of the distal portion of the distal tapered portion of the frame. In some applications, the holes are cut so that they extend to the distal end of the distal tapered portion of the frame, such that there is a single hole that extends around the entire circumference of the frame and to the distal end of the distal tapered portion of the frame.

[0156] The present invention will be more fully understood from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0157] Figure 1A 、 Figure 1B and Figure 1C is a schematic diagram of a ventricular assist device according to some applications of the present invention, the distal end of the ventricular assist device being configured for placement in the left ventricle of a subject;

[0158] Figure 2 is a schematic diagram of a frame housing an impeller of a ventricular assist device according to some applications of the present invention;

[0159] Figure 3A 、 Figure 3B 、 Figure 3C 、 Figure 3D and Figure 3E is a schematic diagram of an impeller or portion thereof of a ventricular assist device according to some applications of the present invention;

[0160] Figure 4 is a schematic diagram of an impeller disposed inside a frame of a ventricular assist device according to some applications of the present invention;

[0161] Figure 5A and Figure 5B is a schematic diagram of an impeller and a frame of a ventricular assist device in a non-radially constrained state and a radially constrained state, respectively, according to some applications of the present invention;

[0162] Figure 6A and Figure 6B is a schematic diagram of a ventricular assist device with an impeller of the ventricular assist device at various stages of a motion cycle relative to a frame of the ventricular assist device according to some applications of the present invention;

[0163] Figure 7 is a schematic diagram of a motor unit of a ventricular assist device according to some applications of the present invention;

[0164] Figure 8A and Figure 8B is a schematic diagram of a motor unit of a ventricular assist device according to some applications of the present invention;

[0165] Figure 9A and Figure 9B is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including a liner positioned on the inside of a frame housing an impeller;

[0166] Figure 10A 、 Figure 10B and Figure 10C is a schematic diagram of a frame of a ventricular assist device including a protective braid at a distal end thereof according to some applications of the present invention;

[0167] Figure 11A 、 Figure 11B 、 Figure 11C and Figure 11D is a schematic diagram of a pump outlet tube defining a blood inlet opening at a distal end thereof according to some applications of the present invention; and

[0168] Figure 12A and Figure 12B is a schematic diagram of a pump outlet tube defining a blood inlet opening at a distal end thereof according to some applications of the present invention;

[0169] Figure 13A and Figure 13B is a schematic diagram of a pump outlet tube defining a blood inlet opening at a distal end thereof according to some applications of the present invention;

[0170] Figure 14A and Figure 14B is a schematic diagram of a frame of a ventricular assist device including a protective braid at a proximal end thereof according to some applications of the present invention; and

[0171] Figure 15 is a schematic diagram of a pump outlet tube defining a blood outlet opening at a proximal end thereof, according to some applications of the present invention.

[0172] Detailed description of the embodiments

[0173] Now refer to Figure 1A 、 Figure 1B and Figure 1C , which are schematic illustrations of a ventricular assist device 20 according to some applications of the present invention, the distal end of the ventricular assist device being configured to be positioned in a left ventricle 22 of a subject. Figure 1A shows an overview of a ventricular assist device system comprising a console 21 and a motor unit 23, Figure 1B shows a ventricular assist device inserted into the left ventricle of a subject, and Figure 1C The pump head portion 27 of the ventricular assist device is shown in more detail. The ventricular assist device includes a pump outlet tube 24 that passes through the subject's aortic valve 26 such that a proximal end 28 of the pump outlet tube is disposed in the subject's aorta 30 and a distal end 32 of the pump outlet tube is disposed within the left ventricle 22. The pump outlet tube 24 (which is sometimes referred to herein as a "blood pump tube") is typically an elongated tube with an axial length that is typically much greater than its diameter. The scope of the present invention includes using the apparatus and methods described herein in anatomical locations other than the left ventricle and aorta. Accordingly, the ventricular assist device and / or portions thereof are sometimes referred to herein (in the specification and claims) as a blood pump.

[0174] For some applications, a ventricular assist device is used to assist the function of the left ventricle of a subject during percutaneous coronary intervention. In this case, the ventricular assist device is typically used for a period of up to 6 hours (e.g., up to 10 hours) during which there is a risk of hemodynamic instability (e.g., during or immediately after percutaneous coronary intervention). Alternatively or additionally, the ventricular assist device is used to assist the function of the left ventricle of a subject for a longer period of time (e.g., for example, 2 days-20 days, e.g., 4 days-14 days) in a patient suffering from cardiogenic shock, which can include any low cardiac output state (e.g., acute myocardial infarction, myocarditis, cardiomyopathy, postpartum, etc.). For some applications, the ventricular assist device is used to assist the function of the left ventricle of a subject for even longer periods of time (e.g., weeks or months), for example, in "bridge to recovery" therapy. For some such applications, the ventricular assist device is permanently or semi-permanently implanted, and the impeller of the ventricular assist device is powered percutaneously, for example, using an external antenna magnetically coupled to the impeller.

[0175] like Figure 1B As shown, Figure 1B Steps for deploying a ventricular assist device in the left ventricle are shown, with the distal end of the ventricular assist device typically being guided to the left ventricle over a guidewire 10. During insertion of the distal end of the device into the left ventricle, a delivery catheter 143 is positioned over the distal end of the device. Once the distal end of the device is positioned in the left ventricle, the delivery catheter is typically retracted into the aorta and the guidewire is withdrawn from the subject's body. Typically, retraction of the delivery catheter causes the self-expanding component of the distal end of the device to assume a non-radially constrained configuration, as described in further detail below. Typically, the ventricular assist device is inserted into the subject's body to provide acute treatment to the subject. For some applications, in order to withdraw the left ventricular device from the subject's body at the conclusion of treatment, the delivery catheter is advanced over the distal end of the device, which causes the self-expanding component of the distal end of the device to assume a radially constrained configuration. Alternatively or additionally, the distal end of the device is retracted into the delivery catheter, which causes the self-expanding component of the distal end of the device to assume a radially constrained configuration.

[0176] For some applications (not shown), the ventricular assist device and / or delivery catheter 143 includes an ultrasound transducer at its distal end, and the ventricular assist device is advanced toward the subject's ventricle under ultrasound guidance.

[0177] refer to Figure 1C, which shows in more detail the pump head portion 27 of the ventricular assist device 20 according to some applications of the present invention. Typically, the impeller 50 is disposed within the distal portion 102 of the pump outlet tube 24 and is configured to pump blood from the left ventricle into the aorta by rotation. The pump outlet tube typically defines one or more blood inlet openings 108 at the distal end of the pump outlet tube, and during operation of the impeller, blood flows from the left ventricle into the pump outlet tube through the blood inlet openings. Figure 1C As shown, for some applications, the pump outlet tube defines a single axially facing blood inlet opening. Alternatively, the pump outlet tube defines multiple lateral blood inlet openings (e.g., Figure 1B For some applications, proximal portion 106 of the pump outlet tube defines one or more blood outlet openings 109 through which blood flows from the pump outlet tube into the ascending aorta during impeller operation.

[0178] For some applications, a console 21 (e.g., a computer processor 25) is typically included. Figure 1A For example, a computer processor may control motor 74 (as shown) to drive the impeller to rotate. Figure 7 As shown), the motor 74 is provided in the motor unit 23 (as Figure 1A ) and via a drive cable 130 (as Figure 7 ) drives the impeller to rotate. For some applications, the computer processor is configured to detect physiological parameters of the subject (e.g., left ventricular pressure, cardiac afterload, rate of change of left ventricular pressure, etc.) and control the rotation of the impeller in response thereto, as described in further detail below. Typically, the operations performed by the computer processor described herein convert the physical state of the memory into a different magnetic polarity, charge, etc., depending on the memory technology used, which is an actual physical article that communicates with the computer processor. The computer processor 25 is typically a hardware device programmed with computer program instructions to produce a special-purpose computer. For example, when programmed to perform the techniques described herein, the computer processor 25 typically acts as a special-purpose ventricular assist computer processor and / or a special-purpose blood pump computer processor.

[0179] For some applications, the cleaning system 29 (in Figure 1A ) drives fluid (e.g., a glucose solution) through various portions of the ventricular assist device 20, for example, to cool various portions of the device, to clean and / or lubricate interfaces between rotating portions and fixed supports, and / or to flush debris from various portions of the device.

[0180] Typically, along the distal portion 102 of the pump outlet tube 24, the frame 34 is disposed around the impeller 50 within the pump outlet tube. The frame is typically made of a shape memory alloy, such as nitinol. For some applications, the shape memory alloy of the frame is shaped so that in the absence of any force being applied to the distal portion 102 of the tube 24, at least a portion of the frame (and therefore the distal portion 102 of the tube 24) exhibits a generally circular, elliptical, or polygonal cross-sectional shape. By exhibiting its generally circular, elliptical, or polygonal cross-sectional shape, the frame is configured to maintain the distal portion of the pump outlet tube in an open state. Typically, during operation of the ventricular assist device, the distal portion of the pump outlet tube is configured to be placed within the body of a subject such that the distal portion of the pump outlet tube is at least partially disposed within the left ventricle.

[0181] For some applications, along the proximal portion 106 of the pump outlet tube 24, the frame is not disposed within the pump outlet tube, and thus the pump outlet tube is not supported in the open position by the frame 34. The pump outlet tube 24 is typically made of a collapsible material that is impermeable to blood. For example, the pump outlet tube 24 can include polyurethane, polyester, and / or silicone. Alternatively or additionally, the pump outlet tube can be made of polyethylene terephthalate (PET) and / or polyether block amide (e.g., ). For some applications (not shown), the pump outlet tube is reinforced with a reinforcing structure (e.g., a braided reinforcing structure such as a braided nitinol tube). Typically, the proximal portion of the pump outlet tube is configured to be positioned such that it is at least partially disposed within the ascending aorta of the subject. For some applications, the proximal portion of the pump outlet tube passes through the subject's aortic valve, from the subject's left ventricle, into the subject's ascending aorta, such as Figure 1B shown.

[0182] As described above, the pump outlet tube typically defines one or more blood inlet openings 108 at the distal end of the pump outlet tube, and during impeller operation, blood flows from the left ventricle into the pump outlet tube via the blood inlet openings. For some applications, the proximal portion of the pump outlet tube defines one or more blood outlet openings 109, and during impeller operation, blood flows from the pump outlet tube into the ascending aorta via the blood outlet openings. Typically, the pump outlet tube defines a plurality of blood outlet openings 109, for example, between two blood outlet openings and eight blood outlet openings (for example, between two blood outlet openings and four blood outlet openings). During impeller operation, the pressure of the blood flow through the pump outlet tube typically maintains the proximal portion of the tube in an open state. For some applications, for example, in the event of an impeller failure, the proximal portion of the pump outlet tube is configured to collapse inward in response to the pressure outside the proximal portion of the pump outlet tube exceeding the pressure inside the proximal portion of the pump outlet tube. In this way, the proximal portion of the pump outlet tube acts as a safety valve, thereby preventing blood flow from the aorta from entering the left ventricle in the reverse direction.

[0183] Reference again Figure 1C , for some applications, the frame 34 is shaped such that the frame defines a proximal tapered portion 36, a central cylindrical portion 38, and a distal tapered portion 40. Typically, the proximal tapered portion is proximally facing, e.g., oriented such that the narrow end of the cone is proximal relative to the wide end of the cone. More typically, the distal tapered portion is distally facing, e.g., oriented such that the narrow end of the cone is distal relative to the wide end of the cone. For some applications, the pump outlet tube 24 extends to the end of the cylindrical portion 38 (or slightly proximal or distal thereto) such that the distal end of the pump outlet tube defines a single axially facing blood inlet opening 108, e.g., Figure 1C For some applications, a liner 39 is laid over at least a portion of frame 34 (eg, along all or a portion of a central cylindrical portion of the frame). Figure 1C An embodiment of the pump head portion is shown without the liner 39, but several figures (e.g. Figure 4 、 Figure 5A 、 Figure 6A-Figure 6B 、 Figure 9A-9B 、 Figures 10A-10C 、 Figure 11A 、 Figure 11C 、 Figure 13A and Figures 14A-14B ) shows an embodiment of a pump head portion including a liner 39. Depending on the respective application, the liner partially overlaps or completely overlaps the pump outlet pipe 24 on the portion of the frame lined with the liner, as described below with reference to Figure 9A-9B As described in further detail.

[0184] Typically, the pump outlet tube 24 includes a tapered proximal portion 42 and a cylindrical central portion 44. The proximal tapered portion is typically proximally facing, e.g., facing such that the narrow end of the cone is proximal relative to the wide end of the cone. Typically, the blood outlet opening 109 is defined by the pump outlet tube 24 such that the opening extends at least partially along the proximal tapered section of the tube 24. For some such applications, the blood outlet opening is teardrop shaped, e.g., Figure 1C Typically, the teardrop-shaped nature of the blood outlet opening, combined with the opening extending at least partially along the proximal tapered section of the tube 24, causes blood to flow out of the blood outlet opening at its location along flow lines that are substantially parallel to the longitudinal axis of the tube 24.

[0185] For some applications (not shown), the diameter of the pump outlet tube 24 varies along the length of the central portion of the pump outlet tube, so that the central portion of the pump outlet tube has a frusto-conical shape. For example, the central portion of the pump outlet tube can widen from its proximal end to its distal end, or can narrow from its proximal end to its distal end. For some applications, at its proximal end, the central portion of the pump outlet tube has a diameter between 5 mm and 7 mm, while at its distal end, the central portion of the pump outlet tube has a diameter between 8 mm and 12 mm.

[0186] Reference again Figure 1C , the ventricular assist device typically includes a distal end element 107 that is disposed distally relative to the frame 34, and the distal end element 107 includes an axial shaft receiving tube 126 and a distal end portion 120. Typically, the axial shaft receiving tube is configured to receive the distal portion of the axial shaft 92 of the pump head portion during axial reciprocating movement of the axial shaft (as described in further detail below) and / or during delivery of the ventricular assist device. (Typically, during delivery of the ventricular assist device, the frame is maintained in a radially constrained configuration, which typically results in the axial shaft being disposed in a different position relative to the frame relative to the disposition of the axial shaft relative to the frame during operation of the ventricular assist device). Typically, the distal end portion 120 is configured to assume a curved shape when deployed within the left ventricle of the subject, for example, as Figure 1C For some applications, the curvature of the distal tip portion is configured to provide an atraumatic tip to ventricular assist device 20. Alternatively or additionally, the distal tip portion is configured to separate blood inlet opening 108 of the ventricular assist device from the wall of the left ventricle.

[0187] like Figure 1BAs shown in the enlarged portion of the figure, for some applications, the pump outlet tube 24 extends to the end of the distal tapered portion 40 of the frame, and the pump outlet tube defines a plurality of lateral blood inlet openings 108, as described in further detail below. For such applications, the pump outlet tube typically defines a distal tapered portion that faces distally, i.e., the narrow end of the cone is distal relative to the wide end of the cone. For some such applications (not shown), the pump outlet tube defines two to four lateral blood inlet openings (e.g., four lateral blood inlet openings, as shown). Typically, for such applications, each blood inlet opening defines an area greater than 20 square millimeters (e.g., greater than 30 square millimeters), and / or less than 60 square millimeters (e.g., less than 50 square millimeters), such as 20-60 square millimeters, or 30-50 square millimeters. Alternatively or additionally, the outlet tube defines a greater number of smaller lateral blood inlet openings, for example, more than 10 blood inlet openings, more than 50 blood inlet openings, more than 200 blood inlet openings, or more than 400 blood inlet openings, for example, 50-100 blood inlet openings, 100-400 blood inlet openings, or 400-600 blood inlet openings. For some such applications, each blood inlet opening defines an area greater than 0.05 square millimeters (e.g., greater than 0.1 square millimeters) and / or less than 3 square millimeters (e.g., less than 1 square millimeter), for example, 0.05 square millimeters to 3 square millimeters or 0.1 square millimeters to 1 square millimeter. Alternatively, each blood inlet opening defines an area greater than 0.1 square millimeters (e.g., greater than 0.3 square millimeters) and / or less than 5 square millimeters (e.g., less than 1 square millimeter), for example, 0.1 square millimeters to 5 square millimeters or 0.3 square millimeters to 1 square millimeter.

[0188] Now refer to Figure 2 , Figure 2 is a schematic diagram of a frame 34 housing an impeller of a ventricular assist device 20 according to some applications of the present invention. Frame 34 is typically made of a shape memory alloy such as Nitinol, and the shape memory alloy of the frame is shaped so that a central portion of the frame (and therefore tube 24) assumes a generally circular, elliptical, or polygonal cross-sectional shape in the absence of any force applied to the pump outlet tube 24. By assuming its generally circular, elliptical, or polygonal cross-sectional shape, the frame is configured to hold a distal portion of the tube in an open state.

[0189] Typically, the frame is a stent-like frame in that it includes struts that in turn define the cells. More typically, the frame is covered by the pump outlet tube 24 and / or by a liner 39, as described below with reference to Figure 9A-9BAs described below, for some applications, impeller 50 undergoes axial reciprocating motion relative to frame 34. Typically, during this motion of the impeller relative to the frame, the portion of the impeller defining the maximum span is located within central cylindrical portion 38 of frame 34. In some cases, if the cells of central cylindrical portion 38 of frame 34 are too large, pump outlet tube 24 and / or liner 39 may be stretched between the edges of the cells, causing pump outlet tube 24 and / or liner 39 to not define a circular cross-section. For some applications, if this occurs in the region of the impeller defining the maximum span, the gap between the impeller blade edge and tube 24 (and / or liner) at that location is not constant during the impeller's rotational cycle. For some applications, this may result in increased hemolysis compared to a situation where a constant gap existed between the impeller blade edge and tube 24 (and / or liner) at that location during the impeller's rotational cycle.

[0190] refer to Figure 2 At least in part to account for the issues described in the previous paragraph, within the central cylindrical portion 38 of the frame 34, the frame defines a large number of relatively small cells. Typically, when the frame is disposed in its non-radially constrained configuration, the maximum cell width CW of each cell within the cylindrical portion of the frame (i.e., the distance from the inner edge of the strut at the central junction on one side of the cell to the inner edge of the strut at the central junction on the other side of the cell, as measured around the circumference of the cylindrical portion 38) is less than 2 mm, e.g., between 1.4 mm and 1.6 mm, or between 1.6 mm and 1.8 mm. Because the cells are relatively small, the liner 39 defines a substantially circular cross-section within the cylindrical portion of the frame.

[0191] Still refer to Figure 2 , and starting from the distal end of the frame (on the right side of the figure), the frame typically defines the following portions: (a) a coupling portion 31 via which the frame is coupled to the distal support housing 118H of the ventricular assist device (at Figure 5A), (a) distal tapered portion 40, (c) cylindrical portion 38, (d) proximal tapered portion 36, and (e) proximal strut junction 33. As shown, as the frame transitions from the proximal end of the frame toward the center of the frame (e.g., as the frame transitions from the proximal strut junction 33, through the proximal tapered portion 36, and to the central cylindrical portion 38), the struts 37 of the frame pass through junctions 35 where two struts branch off from a single strut in a Y-shape. As described in further detail below, the frame 34 is typically placed in a delivery catheter 143 in a radially constrained (i.e., crimped) configuration by the frame being axially elongated. Additionally, the frame typically transfers its radial narrowing to the impeller, and the impeller becomes radially constrained by axially elongating within the frame. For some applications, the struts of the frame configured in the manner described above facilitate transferring axial extension from the delivery catheter (or other device configured to crimp the frame) to the frame, which in turn facilitates transferring the axial extension to the impeller. This is because the pair of struts branching from each joint 35 are configured to pivot about the joint and move closer to each other, thereby closing.

[0192] Still refer to Figure 2 During assembly of the ventricular assist device, initially the distal coupling portion 31 is coupled to the distal support housing 118H (eg, via a snap-fit ​​mechanism). Figure 5A For some applications, the proximal strut joint 33 remains open at this stage so that the impeller is placed within the frame via the proximal end of the frame. Figure 2 The configuration of the frame 34 shown is for use in applications where the pump outlet tube extends to the distal end of the frame 34 (e.g., as Figure 1B In this case, the impeller cannot be inserted through the distal end of the frame because the distal end of the frame is covered by the pump outlet tube 24. During assembly of the ventricular assist device, the proximal strut joint is closed after the impeller is inserted through the proximal end of the frame. For some applications, the proximal strut joint surrounds the proximal support housing 116H (at Figure 5A The outer side of the closure is shown in FIG. Figure 5A-5B Typically, the fixing element 117 (e.g., Figure 5A A ring (shown in ) surrounds the outside of the proximal support housing 116H to maintain the strut joint in its closed configuration.

[0193] Typically, when arranged in its non-radially constrained configuration, the frame 34 has a total length greater than 25 mm (e.g., greater than 30 mm) and / or less than 50 mm (e.g., less than 45 mm), for example, 25 mm-50 mm or 30 mm-45 mm. Typically, when arranged in its radially constrained configuration (within the delivery catheter 143), the length of the frame increases by 2 mm to 5 mm. Typically, when arranged in its non-radially constrained configuration, the central cylindrical portion of the frame 34 has a length greater than 10 mm (e.g., greater than 12 mm) and / or less than 25 mm (e.g., less than 20 mm), for example, 10 mm-25 mm or 12 mm-20 mm. For some applications, the ratio of the length of the central cylindrical portion of the frame to the total length of the frame is greater than 1:4 and / or less than 1:2, for example, between 1:4 and 1:2.

[0194] Now refer to Figure 3A-Figure 3E , Figure 3A-Figure 3E is a schematic diagram of an impeller 50 or portion thereof according to some applications of the present invention. Typically, the impeller includes at least one outer helical elongated element 52 that is wound around a central axial spring 54 such that the helical structure defined by the helical elongated element is coaxial with the central axial spring. Typically, the impeller includes two or more helical elongated elements (e.g., three helical elongated elements, such as Figure 3A-3C ). 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, each helical elongated element and the central axial spring support a membrane 56 of material (e.g., an elastomer, such as polyurethane, and / or silicone) between them. For some applications, the membrane of material includes a Nitinol sheet embedded therein, for example, to reinforce the membrane of material. For illustrative purposes, the impeller is Figure 3A The material is shown without. Figure 3B and Figure 3C A view of an impeller is shown where the material is supported between the helical elongated element and the spring. Figure 3D and Figure 3E Shown respectively with Figure 3B and Figure 3C A similar view of the impeller shown in FIG, but some features of the impeller differ from those of the Figure 3B and Figure 3C The features shown in are described in detail below.

[0195] Each helical elongate member defines a respective impeller blade together with a membrane extending from the helical elongate member to the spring, wherein the helical elongate member defines the outer edge of the blade and the axial spring defines the axis of the impeller. Typically, the membrane of material extends along and over the spring. For some applications, suture 53 (e.g., polyester suture, such as Figure 3A-3C5. The suture is typically wound around the helical elongate member (shown). Typically, the suture is configured to facilitate bonding between the membrane of material (which is typically an elastomer, such as polyurethane or silicone) and the helical elongate member (which is typically a shape memory alloy, such as nitinol). For some applications, a suture (e.g., polyester suture, not shown) is wound around spring 54. Typically, the suture is configured to facilitate bonding between the membrane of material (which is typically an elastomer, such as polyurethane or silicone) and the spring (which is typically a shape memory alloy, such as nitinol).

[0196] Typically, the proximal end of the spring 54 and the proximal end of the spiral elongate element 52 extend from a proximal bushing (i.e., a sleeve support) 64 of the impeller such that the proximal end of the spring 54 and the proximal end of the spiral elongate element 52 are disposed at similar radial distances from one another to the longitudinal axis of the impeller. Similarly, typically, the distal end of the spring 54 and the distal end of the spiral elongate element 52 extend from a distal bushing 58 of the impeller such that the distal end of the spring 54 and the distal end of the spiral elongate element 52 are disposed at similar radial distances from one another to the longitudinal axis of the impeller. The spiral elongate element typically rises gradually from the proximal bushing before reaching a maximum span and then gradually descends toward the distal bushing. Typically, the spiral elongate element is symmetrical along its length such that the ascending portion of its length is symmetrical relative to the descending portion of its length. Typically, the impeller defines a cavity 62 (e.g., Figure 3C ), the cavity typically extends through and is defined by the impeller's spring 54 and proximal and distal bushings 64, 58.

[0197] Now refer to Figure 4 , which is a schematic diagram of an impeller 50 disposed within a frame 34 of a ventricular assist device 20 according to some applications of the present invention. For some applications, a liner 39 is lined on the frame within at least a portion of the frame 34 (e.g., along all or a portion of the central cylindrical portion 38 of the frame). Depending on the respective application, the liner partially or completely overlaps the pump outlet tube 24 over the portion of the frame lined with the liner, as described below with reference to FIG. Figure 9A-9B As described in further detail.

[0198] like Figure 4As shown, typically, there is a gap G between the outer edge of the impeller 50 and the liner 39, even at the position where the impeller has its largest span. For some applications, it is desirable that the gap between the outer edge of the impeller's blades and the liner 39 be relatively small so that the impeller effectively pumps blood from the subject's left ventricle into the subject's aorta. (Note that because the gap between the outer edge of the impeller 50 and the liner 39 is relatively small even at the position where the impeller has its largest span, and because of the shape of the impeller, the impeller functions as an axial flow impeller, wherein the impeller pumps blood in an axial direction from the distal end of the pump outlet tube 24 to the proximal end of the pump outlet tube.) It is also desirable that the gap between the outer edge of the impeller's blades and the inner surface of the frame 34 be maintained throughout the rotation of the impeller within the frame 34, for example, to reduce the risk of hemolysis.

[0199] For some applications, when both impeller 50 and frame 34 are arranged in a non-radially constrained configuration and before the impeller is operated, at the location where the impeller has the largest span, the gap G between the outer edge of the impeller and liner 39 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), for example, 0.05 mm to 1 mm, or 0.1 mm to 0.4 mm. For some applications, when the impeller is arranged in its non-radially constrained configuration and before the impeller is operated, the impeller outer diameter at the location where the impeller has the largest outer diameter is greater than 7 mm (e.g., greater than 8 mm) and / or less than 10 mm (e.g., less than 9 mm), for example, 7 mm to 10 mm, or 8 mm to 9 mm. For some applications, when frame 34 is positioned in its non-radially constrained configuration, the inner diameter of frame 34 (as measured from the inner side of liner 39 on one side of the frame to the inner side of the liner on the opposite side of the frame) is greater than 7.5 mm (e.g., greater than 8.5 mm) and / or less than 10.5 mm (e.g., less than 9.5 mm), for example, between 7.5 mm and 10.5 mm, or between 8.5 mm and 9.5 mm. For some applications, when frame 34 is positioned in its non-radially constrained configuration, the outer diameter of frame 34 is greater than 8 mm (e.g., greater than 9 mm), and / or less than 13 mm (e.g., less than 12 mm), for example, between 8 mm and 13 mm, or between 9 mm and 12 mm.

[0200] Typically, the axial shaft 92 passes through the axis of the impeller 50 via the cavity 62 of the impeller. More typically, the axial shaft is rigid, such as a rigid tube. For some applications, the proximal bushing 64 of the impeller is coupled to the shaft such that the axial position of the proximal bushing relative to the shaft is fixed and the distal bushing 58 of the impeller is slidable relative to the shaft. For example, the proximal bushing can be coupled to a coupling element 65 (in the case of a slidable sleeve) provided on the axial shaft, such as via a snap-fit ​​mechanism. Figure 4). Alternatively, the impeller's distal bushing 58 is coupled to the shaft such that the distal bushing's axial position relative to the shaft is fixed and the impeller's proximal bushing 64 is slidable relative to the shaft. The axial shaft itself is radially stabilized via proximal and distal radial supports 116, 118. In turn, the axial shaft radially stabilizes the impeller relative to the inner surface of the frame 34 by passing through the cavity 62 defined by the impeller, such that even relatively small gaps (e.g., such as those described above) between the outer edges of the impeller's blades and the inner surface of the frame 34 are maintained during rotation of the impeller.

[0201] Reference again Figure 3A-3C For some applications, the impeller includes a plurality of elongated elements 67 extending radially from the central axial spring 54 to the outer helical elongated element 52. The elongated elements are typically flexible but substantially inextensible along the axis defined by the elongated elements. More typically, each elongated element is configured to not apply a force to the helical elongated element unless a force acts on the impeller to cause the helical elongated element to move radially outward, so that (in the absence of the elongated elements) the spacing between the helical elongated element and the central axial spring is greater than the length of the elongated element. For example, the elongated element may include a rope (e.g., polyester, and / or another polymer or natural material containing fibers) and / or a wire (e.g., nitinol wire, and / or wire made from a different alloy or metal).

[0202] For some applications, the elongated element 67 holds the spiral elongated element (which defines the outer edges of the impeller's blades) within a given distance relative to the central axial spring. In this way, the elongated element is configured to prevent the outer edges of the impeller from being forced radially outward due to forces exerted on the impeller during rotation of the impeller. The elongated element is thereby configured to maintain a gap between the outer edges of the impeller's blades and the inner surface of the frame 34 during rotation of the impeller. Typically, more than one (e.g., more than two) and / or fewer than eight (e.g., fewer than four) elongated elements 67 are used in the impeller, wherein each elongated element is typically folded in half (i.e., extending radially from the central axial spring 54 to the outer spiral elongated element 52, and then returning from the spiral elongated element to the central axial spring). For some applications, multiple elongated elements are formed from a single rope or single wire, wherein each elongated element extends from the spring to a corresponding spiral elongated element and back to the spring.

[0203] Now refer to Figure 3D and Figure 3E , Figure 3D and Figure 3Eis a schematic diagram of an impeller 50 that, in accordance with some applications of the present invention, includes a single, integrated impeller over-extension prevention member 72 defining a plurality of elongated members 67. For some applications, the impeller over-extension prevention member 72 (which defines a plurality of elongated members 67) is used as a replacement for the elongated members 67, such as Figure 3A-3C As shown. For some applications, element 72 defines a ring 73 and a plurality of elongated elements 67 extending radially from the ring. For some applications, instead of threading a cord and / or wire around spring 54, the ring 73 of element 72 is placed around the spring, for example, by being placed around tube 70, which is typically positioned at a longitudinally central location of the spring. The ends of each elongated element 67 are then coupled to a respective helical elongated element 52. As described above, the elongated elements 67 are typically flexible but substantially incapable of stretching along the axis defined by the elongated elements. Further typically, each of the elongated elements 67 is configured to be substantially non-resistant to compression. More specifically, each elongated element 67 is configured to exert a tensile force on the helical elongated element 52 that prevents the helical elongated element 52 from moving radially outward, such that (in the absence of the elongated elements 67) the spacing between the helical elongated element 52 and the central axial spring 54 would be greater than the length of the elongated element 67. The impeller over-extension preventing element is configured to prevent radial expansion of the impeller when a force acts on the impeller that would cause helical elongated element 52 to move radially outward (in the absence of elongated element 67). Typically, a corresponding elongated element 67 is disposed within each impeller blade and configured to prevent radial expansion of the impeller blade. For some applications, element 72 is made of polyester and / or another polymer or natural material containing fibers and / or Nitinol (or a similar shape memory alloy).

[0204] Note that the scope of this application includes the use of a single integrated impeller over-extension prevention element 72 with an impeller having Figure 3D-Figure 3E For example, a single integrated impeller over-extension prevention element 72 may be used with an impeller having an axial structure configured differently than the spring 54. Typically, the axial structure defines a cavity therethrough such that the impeller defines a cavity 62 therethrough.

[0205] For some applications, the following assembly technique is used to manufacture the impeller while enhancing the bonding of the elastomeric material used to form membrane 56 to the at least one helical elongated element. Typically, the bonding of the elastomeric material to the at least one helical elongated element is performed in a manner that does not result in protrusions from the effective edge of the impeller blade. Furthermore, the bonding of the elastomeric material to the at least one helical elongated element is typically performed in a manner that rounds the edges of the helical elongated element by the elastomeric material, thereby providing a rounded outer edge for the impeller blade. The proximal bushing 64, distal bushing 58, and helical elongated element 52 are cut from a tube of shape memory material (e.g., Nitinol). The cutting of the tube and the shaping of the shape memory material are typically performed such that the helical elongated element and the bushing are defined by the cut and shape-set tube of shape memory material. For some applications, the helical elongated element is subjected to a plasma treatment prior to being coupled to the spring 54. Alternatively or additionally, the helical elongated element is coated with a coupling agent prior to being coupled to the spring 54. Typically, a coupling agent is selected that has at least two functional groups that are configured to bind to the helical elongated element and the elastomeric material, respectively. For example, a silane compound, such as n-(2-aminoethyl)-3-aminopropyltrimethoxysilane, can be used, which contains a first functional group (e.g., (OH)) that is configured to bind to the helical elongated element (which is typically made of an alloy such as Nitinol) and a second functional group (e.g., (NH2)) that is configured to bind to the elastomeric material. Typically, the functional groups in the coupling agent are only effective for a given time period (e.g., about one hour or less). Therefore, during this time period, a layer of elastomeric material is applied around the helical elongated element. Typically, the layer of elastomeric material is the same elastomeric material as used in membrane 56 or a similar elastomeric material. For example, a polycarbonate-based thermoplastic polyurethane, such as Aromatic Carbothane TM (e.g. Aromatic Carbothane TM 75A) can be used in the film 56, and the coating layer can be the same polycarbonate-based thermoplastic polyurethane, or a similar polycarbonate-based thermoplastic polyurethane, such as (For example 90A).

[0206] As described above, the proximal bushing 64, the distal bushing 58 and the spiral elongated element 52 are typically cut from a tube of shape memory material (e.g., Nitinol). For some applications, the spring 54 is coupled to the spiral elongated element after the coating has been applied to the spiral elongated element 52. Typically, the spring 54 is inserted into the cut and shaped tube so that the spring extends along the length of the tube at least from the proximal bushing to the distal bushing. For some applications, the spring is inserted into the cut and shaped tube when the spring is in axial compression and is configured to remain in place relative to the tube by applying a radial force on the proximal and distal bushings. Alternatively or additionally, portions of the spring are welded to the proximal and distal bushings. For some applications, the spring is cut from a tube of shape memory material (e.g., Nitinol). For some such applications, the spring is configured such that when the spring is disposed in a non-radially constrained configuration (where the spring is typically disposed in a non-radially constrained configuration during operation of the impeller), there is substantially no gap between a coil of the spring and its adjacent coils.

[0207] Typically, at this stage, the over-extension prevention element 72 is placed between the spring and the helical elongate member, as described above, thereby forming an assembly comprising the coated helical elongate member 52 , the spring 54 and the over-extension prevention element 72 .

[0208] For some applications, at this stage, the assembly of the coated helical elongated element 52, spring 54 and anti-overextension element 72 is sprayed with another layer of elastomeric material. Typically, the elastomeric material that is sprayed is the same elastomeric material as that used for the membrane 56 or a similar elastomeric material. For example, a polycarbonate-based thermoplastic polyurethane, such as Aromatic Carbothane TM (e.g. Aromatic Carbothane TM 75A) can be used as the membrane 56, and the spray material can be the same polycarbonate-based thermoplastic polyurethane, or a similar polycarbonate-based thermoplastic polyurethane, such as (For example 90A). For some applications, applying the spray coating to the helical elongated member rounds the helical elongated member. Typically, when the helical elongated member has a circular cross-section, the elastomeric material forms a layer having a substantially uniform thickness at the interface with the helical elongated member. For some applications, as described in the previous paragraph, applying the coating of elastomeric material to the helical elongated member at least partially rounds the helical elongated member.

[0209] For some applications, after the spray coating has been applied, the assembly of the coated helical elongated element 52, spring 54 and anti-overextension element 72 is dipped into the elastomer from which the membrane 56 is made. For some applications, the material from which the membrane is made is an elastomeric material having an ultimate elongation greater than 300%, such as greater than 400%. Typically, the material has a relatively low molecular weight. For some applications, the material has a melt flow index (which is an indirect measure of molecular weight) of at least 4, such as at least 4.3. For some applications, the material has an ultimate tensile strength greater than 6000 psi, such as greater than 7000 psi, or greater than 7500 psi. For some applications, the material is a polycarbonate-based thermoplastic polyurethane, such as Carbothane TM For some applications, Aromatic Carbothane TM (e.g. Aromatic Carbothane TM 75A) is used. Typically, this material combines one or more of the following properties: no loss of outer diameter during immersion, resistance to fatigue, resistance to deformity due to curling, and low loss of outer diameter during curling. Subsequently, the material is cured so that it becomes solid, for example by drying it. Typically, at this stage, the impeller is placed on the mandrel so that the mandrel passes through the cavity 62 defined by the bushing and the spring, thereby maintaining the cavity during drying. For some applications, the impeller is rotated while the material for making the membrane is drying, which typically helps to form a film of material with a substantially uniform thickness within each impeller blade. Once the material has dried, the mandrel is typically removed from the cavity 62.

[0210] In light of the above description of applying the film 56 to the spiral elongated element, the scope of the present invention includes any technique for applying additional layers of the same elastomeric material, a different elastomeric material, and / or an intermediary material to the spiral elongated element, whether by spraying, dipping, or a different coating method, prior to immersing the spiral elongated element in the elastomeric material used to make the film 56. For some applications, the additional layers of elastomeric material are configured to round the spiral elongated element and / or serve as an intermediary to enhance the bond between the spiral elongated element and the film 56 of material. For some applications, an intermediary material (e.g., silane) is configured to act as an intermediary to enhance the bond between the spiral elongated element and the film 56 of material.

[0211] Typically, the impeller 50 is inserted into the left ventricle via a catheter while the impeller 50 is in a radially constrained configuration. In the radially constrained configuration, both the helical elongated element 52 and the central axial spring 54 become axially elongated and radially constrained. Typically, the membrane 56 of a material (e.g., silicone and / or polyurethane) changes shape to conform to the shape changes of the helical elongated element and the axial support spring (both of which support the membrane of material). Typically, the use of a spring to support the inner edge of the membrane allows the membrane to change shape without the membrane breaking or collapsing because the spring provides a large surface area to which the inner edge of the membrane is bound. For some applications, the use of a spring to support the inner edge of the membrane reduces the diameter to which the impeller can be radially constrained, compared to, for example, using a rigid shaft to support the inner edge of the membrane, because the diameter of the spring itself can be reduced by axially extending the spring.

[0212] As described above, for some applications, the proximal bushing 64 of the impeller 50 is coupled to the axial shaft 92 such that the axial position of the proximal bushing relative to the shaft is fixed and the distal bushing 58 of the impeller is slidable relative to the shaft. For example, the proximal bushing can be coupled to a coupling element 65 provided on the axial shaft (at Figure 4 ). For some applications, when the impeller is radially constrained for insertion into a ventricle or for withdrawal from a subject, the impeller is axially extended by sliding the distal bushing distally along the axial shaft. Alternatively (not shown), the distal bushing 58 of the impeller is coupled to the shaft such that the axial position of the distal bushing relative to the shaft is fixed and the proximal bushing 64 of the impeller is slidable relative to the shaft. For some applications, when the impeller is radially constrained for insertion into a ventricle or for withdrawal from a subject, the impeller is axially extended by sliding the proximal bushing proximally along the axial shaft. As Figure 3A-Figure 3E 1 and 2. It is shown that after being released within the body of the subject, the impeller assumes its non-radially constrained configuration (wherein the impeller is typically disposed in the non-radially constrained configuration during operation of the impeller).

[0213] Now refer to Figure 5A and Figure 5B , which are schematic illustrations of an impeller 50 and frame 34 of a ventricular assist device 20 in their non-radially constrained and radially constrained states, respectively, according to some applications of the present invention. The impeller and frame are typically positioned in the radially constrained state during transcatheter insertion into a subject and in the non-radially constrained state during operation of the impeller within the left ventricle of the subject.

[0214] like Figure 5BAs shown, the frame and impeller are typically held in a radially constrained configuration by the delivery conduit 143. Typically, in the radially constrained configuration of the impeller, the total length of the impeller is greater than 15 mm (e.g., greater than 20 mm) and / or less than 30 mm (e.g., less than 25 mm), such as 15-30 mm, or 20-25 mm. In addition, typically, in the non-radially constrained configuration of the impeller, the impeller has a length greater than 8 mm (e.g., greater than 10 mm) and / or less than 18 mm (e.g., less than 15 mm), such as 8 mm-18 mm or 10 mm-15 mm. Still further typically, when the impeller and frame 34 are arranged in a radially constrained configuration (e.g., Figure 5B ), the impeller has an outer diameter of less than 2 mm (e.g., less than 1.6 mm), and the frame has an outer diameter of less than 2.5 mm (e.g., less than 2.1 mm).

[0215] As described above, the axial shaft 92 typically passes through the axis of the impeller 50 via the impeller cavity 62. Typically, the impeller's proximal bushing 64 is coupled to the shaft via a coupling element 65 such that the proximal bushing is fixed in axial position relative to the shaft and the impeller's distal bushing 58 is slidable relative to the shaft. (Alternatively, the impeller's distal bushing 58 is coupled to the shaft such that the distal bushing is fixed in axial position relative to the shaft and the impeller's proximal bushing 64 is slidable relative to the shaft.) The axial shaft itself is radially stabilized via proximal and distal radial supports 116 and 118. Typically, a proximal support housing 116H is provided to surround and house the proximal support, and a distal support housing 118H is provided to surround and house the distal support. For some such applications, the radial supports and the support housing are made of corresponding, different materials. For example, the radial support can be made of a first material having a relatively high hardness, such as a ceramic (e.g., zirconia), and the support housing can be made of a second material that can be molded into a desired shape, such as a metal or alloy (e.g., stainless steel, cobalt chromium and / or nitinol).

[0216] For some applications, the axial shaft 92 is made of a metal or alloy, such as stainless steel. For some such applications, the axial shaft is covered with a ceramic sleeve 240 (e.g., a zirconia sleeve) along the area of ​​the axial shaft that contacts either the proximal support 116 and the distal support 118 during operation of the ventricular assist device. In this manner, the radial interface between the axial shaft and the proximal and distal supports is a ceramic-ceramic interface. As described in further detail herein, the impeller and the axial shaft are typically configured to undergo axial reciprocating motion during operation of the ventricular assist device. Thus, for some applications, the axial shaft is covered by the ceramic sleeve along a length greater than 5 mm, e.g., greater than 7 mm, at a location along the axial shaft corresponding to each of the proximal and distal supports. In this manner, the area of ​​the axial shaft that contacts the radial supports is covered by the ceramic sleeve during axial reciprocating motion of the axial shaft.

[0217] For some applications, the proximal support housing 116H and the distal support housing 118H perform additional functions. Referring first to the proximal support housing, as described above, for some applications, the proximal strut joint 33 of the frame 34 is closed around the outside of the proximal support housing. For some applications, the outer surface of the proximal support housing defines a groove that is shaped to receive the proximal strut joint. For example, as shown, the proximal strut joint has a widened head, and the groove defined by the outer surface of the proximal support housing is shaped to conform to the widened head of the proximal strut joint. Typically, a fixing element 117 (which typically includes a ring) surrounds the outside of the proximal support housing 116H to maintain the strut joint in its closed configuration. For some applications, additional portions of the ventricular assist device are coupled to the proximal support housing. For some applications, a drive cable 130 extends from outside the subject's body to the axial shaft 92 and is coupled to the axial shaft. Typically, the drive cable rotates within a first outer tube 140, which serves as a drive cable support tube and extends from outside the subject's body to the proximal support housing. For some applications, the first outer tube is disposed within a second outer tube 142, which also extends from outside the subject's body to the proximal support housing. For some applications, the first outer tube 140 and / or the second outer tube 142 are coupled to the proximal support housing (e.g., using an adhesive). For example, the first outer tube 140 can be coupled to the inner surface of the proximal support housing, and the second outer tube 142 can be coupled to the outer surface of the proximal support housing.

[0218] Referring now to distal support housing 118H, for some applications, distal coupling portion 31 of frame 34 is coupled to an outer surface of distal support housing 118H, e.g., via a snap-fit ​​mechanism. For example, an outer surface of proximal-most portion 119 of distal support housing may include a snap-fit ​​mechanism to which distal coupling portion 31 of frame 34 is coupled. For some applications, distal support 118 is disposed within proximal-most portion 119 of distal support housing, e.g., Figure 5A As described above, for some applications, the pump outlet tube 24 extends to the distal end of the frame 34 and defines a lateral blood inlet opening 108. For some such applications, a coupling portion 41 (e.g., a tubular coupling portion) extends distally from the pump outlet tube, and the coupling portion is coupled to the distal support housing to anchor the distal end of the pump outlet tube. For some applications, the intermediate portion 123 of the distal support housing defines a ridged or threaded outer surface to which the coupling portion 41 of the pump outlet tube is coupled (e.g., by an adhesive). For some applications, the outer surface is ridged to enhance the bond between the distal support housing and the coupling portion 41 of the pump outlet tube. For some applications, the outer surface is threaded to enhance the bond between the distal support housing and the coupling portion 41 of the pump outlet tube and to facilitate application of an adhesive between the outer surface and the coupling portion 41 of the pump outlet tube, as described below with reference to. Figure 12B Detailed description is provided below. For some applications, the distal portion 121 of the distal support housing is configured to reinforce the area (e.g., the axial shaft receiving tube 126 or a portion thereof) to which the distal end of the shaft 92 of the distal tip element 107 moves. Typically, the distal tip element 107 is coupled to the outer surface of the distal portion 121 of the distal support housing (e.g., via an adhesive). For some applications, at least a portion of the outer surface of the distal portion 121 of the distal support housing is ridged and / or threaded to enhance the bond between the distal tip element 107 and the distal support housing.

[0219] As described above, the axial shaft 92 is radially stabilized via the proximal radial support 116 and the distal radial support 118. In turn, the axial shaft radially stabilizes the impeller relative to the inner surface of the frame 34 and the liner 39 by passing through the cavity 62 defined by the impeller so that, as described above, even relatively small gaps (e.g., such as those described above) between the outer edges of the impeller's blades and the liner 39 are maintained during rotation of the impeller. Typically, the impeller itself is not directly disposed within any radial supports or thrust supports. Rather, supports 116 and 118 act as radial supports relative to the axial shaft. Typically, the pump head portion 27 (and more generally the ventricular assist device 20) does not include any thrust supports that are configured to be disposed within the body of a subject and that are configured to resist thrust generated by rotation of the impeller. For some applications, one or more thrust supports are disposed externally to the subject (e.g., in a housing such as Figure 1A 、 Figure 7 and Figure 8A-8B The impeller is positioned within the motor unit 23 shown in FIG. 1 ), and the thrust generated by the rotation of the impeller is resisted only by one or more thrust bearings disposed outside the subject's body. For some applications, mechanical and / or magnetic elements are configured to maintain the impeller within a given axial position range. For example, a magnet (e.g., magnet 82, hereinafter referred to as magnet 82) disposed at the proximal end of the drive cable (e.g., outside the subject's body) may be provided. Figure 7 ) can be configured to impart axial motion to the impeller, and / or to maintain the impeller within a given range of axial positions.

[0220] Now refer to Figure 6A and Figure 6B , which are schematic diagrams of a ventricular assist device 20 showing an impeller 50 of the ventricular assist device at various stages of a motion cycle relative to a frame 34 of the ventricular assist device, according to some applications of the present invention. For some applications, as the impeller rotates to pump blood through tube 24, an axial shaft 92 (to which the impeller is fixed) is driven to cause the impeller to reciprocate axially within the frame 34 by moving the axial shaft in an axial reciprocating motion, as described below with reference to Figure 7As further described in detail. Alternatively or additionally, the impeller and axial shaft are configured to reciprocate axially within frame 34 in response to forces acting on the impeller, without requiring the axial shaft to be actively driven to cause the axial shaft to move in an axially reciprocating manner. Typically, during a subject's cardiac cycle, the pressure differential between the left ventricle and the aorta varies from approximately zero during ventricular contraction (hereinafter referred to as "systole") to a relatively large pressure differential (e.g., 50 mmHg-70 mmHg) during ventricular relaxation (hereinafter referred to as "diastole"). For some applications, due to the increased pressure differential against which the impeller pumps during diastole (and because the drive cable 130 is stretchable), the impeller is pushed distally relative to frame 34 during diastole compared to its position relative to frame 34 during systole. Furthermore, because the impeller is connected to the axial shaft, the axial shaft moves forward. During systole, the impeller (and, therefore, the axial shaft) moves back to its systolic position. In this way, the axial reciprocating motion of the impeller and the axial shaft is generated in a passive manner, ie, the axial shaft and the impeller do not need to be actively driven in order for them to undergo such motion. Figure 6A and Figure 6B The impeller and axial shaft are shown disposed in corresponding positions within the frame 34 during the aforementioned axial reciprocating motion cycle.

[0221] For some applications, by moving in an axial reciprocating motion, the portion of the axial shaft in contact with the proximal and distal supports 116, 118 is continuously varied. For some such applications, assuming all else is equal, in this manner, the frictional forces exerted on the axial shaft by the supports are distributed over a larger area of ​​the axial shaft than if the axial shaft were not moved relative to the supports, thereby reducing wear on the axial shaft. Alternatively or additionally, by moving in an axial reciprocating motion relative to the supports, the axial shaft clears any residue, such as blood residue, from the interface between the axial shaft and the supports.

[0222] For some applications, at the impeller's most proximal position during the impeller's motion cycle, the proximal end of the impeller is within the proximal conical segment of frame 34. For some applications, at the impeller's most distal position during the impeller's motion cycle, the distal end of the impeller is disposed proximal to the distal end of the cylindrical segment of frame 34. Alternatively, the distal end of the impeller is disposed proximal to the distal end of the cylindrical segment of frame 34 even at the impeller's most distal position during the impeller's motion cycle. Typically, the segment of the impeller with the largest impeller span is disposed within the cylindrical portion of frame 34 throughout the cardiac cycle. However, during at least a portion of the cardiac cycle, the proximal portion of the impeller is typically disposed within the proximal conical segment of the frame.

[0223] Reference again Figure 6A and Figure 6B . Typically, the distal end element 107 is a single integrated element that includes both the axial shaft receiving tube 126 and the distal end portion 120. Typically, the axial shaft receiving tube is configured to receive the distal portion of the axial shaft 92 of the pump head portion during axial reciprocating movement of the axial shaft (as described in further detail below) and / or during delivery of the ventricular assist device. (Typically, during delivery of the ventricular assist device, the frame is maintained in a radially constrained configuration, which typically results in the axial shaft being disposed in a different position relative to the frame during delivery than the axial shaft is disposed relative to the frame during operation of the ventricular assist device). For some applications, the distal end portion 120 is configured to be soft such that the distal end portion is configured not to cause tissue damage to the subject even if the distal end portion comes into contact with tissue (e.g., tissue of the left ventricle). For example, the distal end portion 120 or the entire distal end element can be constructed from silicone, polyethylene terephthalate (PET), and / or polyether block amide (e.g., ). For some applications, the distal tip portion defines a lumen 122 therethrough. For some such applications, during insertion of a ventricular assist device into the left ventricle, the guide wire 10 ( Figure 1B ) is first inserted into the left ventricle according to, for example, known techniques. The distal tip portion of the ventricular assist device is then guided to the left ventricle by advancing the distal tip portion over a guidewire disposed within lumen 122. For some applications, a duckbill valve 390 (or a different type of hemostatic valve) is disposed at the distal end of lumen 122 of distal tip portion 120.

[0224] Typically, during insertion of a ventricular assist device into a subject's ventricle, a delivery catheter 143 is placed over the impeller 50 and frame 34 and holds the impeller and frame in their radially constrained configuration. Figure 1B As shown, during insertion of the delivery catheter into a ventricle of a subject, the distal tip element 107 extends distally from the delivery catheter. For some applications, the distal tip element has a protrusion 110 toward its proximal end. Figure 5B (It shows the pump head portion disposed within delivery catheter 143.) For some applications, during insertion of the ventricular assist device into a subject's ventricle, the delivery catheter extends to the proximal side of the protrusion, such that the delivery catheter and the protrusion form a smooth, continuous surface. The distal side of protrusion 110 is tapered, such that the vasculature is exposed to the tapered diameter change and not to any edges caused by the abrupt change in diameter at the interface between the delivery catheter and the distal tip element.

[0225] For some applications, distal tip element 107 defines an overall curvature similar to a question mark or tennis racket, wherein the distal tip element defines a straight proximal portion and a ridge on one side of a longitudinal axis of the straight proximal portion. Typically, as described above, the ventricular assist device is introduced into the ventricle of the subject over a guidewire. Distal tip portion 120 defines cavity 122 such that the distal tip portion is maintained in a straight configuration (e.g., as in FIG. 1 ) during introduction of the ventricular assist device into the ventricle of the subject. Figure 1B For some applications, when the guidewire is removed, the distal tip portion is configured to assume its curved shape. Figure 6A-Figure 6B 390 is disposed therein) spans a more proximal portion of the distal tip portion. Typically, the distal tip portion remains partially straightened due to having a guidewire inserted therethrough (during insertion of a ventricular assist device into the left ventricle), even after the guidewire is removed from the distal tip portion. Typically, the partial straightening of the distal tip portion is such that, when the distal tip portion is disposed within the left ventricle, in the absence of external forces acting on the distal tip portion, the distal tip portion does not define a complete loop.

[0226] Reference again Figure 6A-Figure 6B For some applications, an axial shaft receiving tube 126 extends proximally from the distal end portion 120 of the distal end element 107. As described above, typically, during operation of the impeller 50, the axial shaft undergoes axial reciprocating motion. The axial shaft receiving tube 126 defines a cavity 127 that is configured to receive the axial shaft when the axial shaft extends beyond the distal support 118. For some applications, the axial shaft receiving tube defines a stop 128 at its distal end that is configured to prevent the axial shaft from being advanced beyond the stop. For some applications, the stop comprises a rigid component inserted (e.g., embedded) into the distal end of the shaft receiving tube. Alternatively (not shown), the stop comprises a shoulder between the cavity 127 of the axial shaft receiving tube and the cavity 122 of the distal end portion 120.

[0227] Typically, during normal operation of the impeller, the axial shaft does not contact the stop 128, even when the drive cable 130 (at Figure 5A1 and 2. The axial shaft 128 is also shown in FIG. 1 , when the delivery catheter 50 is maximally extended (e.g., during diastole). However, during retraction of the ventricular assist device 20 from the subject's ventricle, as the delivery catheter is advanced over the impeller 50 and frame 34, the stop 128 is configured to prevent the axial shaft from protruding into the distal end portion. In some instances, there is a risk of the drive cable snapping during advancement of the delivery catheter over the frame and impeller. In the absence of the stop 128, in such circumstances, the axial shaft could protrude into the distal end portion. The stop 128 prevents this from occurring, even in the event of a drive cable snapping.

[0228] It should be noted that at the proximal end of the frame 34, the proximal radial support 116 also acts as a stop by preventing the coupling element 65, and thereby the proximal bushing 64 of the impeller 50, from being able to move beyond the proximal radial support. Typically, during normal operation of the impeller, the coupling element 65 does not contact the proximal radial support 116. However, the proximal radial support 116 is configured to prevent the coupling element 65, and thereby the proximal bushing 64 of the impeller 50, from migrating proximally from within the frame, for example, when the impeller and frame are maintained in a radially constrained (i.e., crimped) configuration within the delivery catheter 143.

[0229] Typically, during operation of the ventricular assist device and throughout the entire axial reciprocating cycle of the impeller, the impeller is positioned relatively close to the distal tip portion. For example, the distance from the impeller to the distal tip portion may be within the furthest 50%, such as within the furthest 30% (or the furthest 20%) of the tube 24 throughout the entire axial reciprocating cycle of the impeller.

[0230] Now refer to Figure 7 , which is a schematic diagram of an exploded view of a motor unit 23 of a ventricular assist device 20 according to some applications of the present invention. For some applications, the console 21 ( Figure 1A ) that controls the rotation of impeller 50 is also configured to control the reciprocating motion of the axial shaft. Typically, both types of motion are generated using motor unit 23. The scope of the present invention includes controlling reciprocating motion of any frequency. For some applications, an indication of the subject's cardiac cycle is detected (e.g., by detecting the subject's ECG), and the reciprocating motion of the axial shaft is synchronized with the subject's cardiac cycle.

[0231] Typically, the motor unit 23 includes a motor 74 that is configured to impart rotational motion to the impeller 50 via a drive cable 130. As described in further detail below, the motor is typically magnetically coupled to the drive cable. For some applications, an axial motion driver 76 is configured to drive the motor so as to move in an axial reciprocating motion (as indicated by the double-headed arrow 79). Typically, due to the magnetic coupling of the motor to the drive cable, the motor imparts reciprocating motion to the drive cable, which in turn imparts the motion to the impeller. As described above and below, for some applications, the drive cable, impeller, and / or axial shaft reciprocate axially in a passive manner, for example, due to periodic changes in the pressure gradient against which the impeller pumps blood. Typically, for such applications, the motor unit 23 does not include an axial motion driver 76.

[0232] For some applications, the magnetic coupling between the motor and the drive cable is Figure 7 As shown. Figure 7 As shown, a set of drive magnets 77 are coupled to the motor via a drive magnet housing 78. For some applications, the drive magnet housing includes a ring 81 (e.g., a steel ring) and the drive magnets are adhered to the inner surface of the ring. For some applications, as shown, a spacer 85 is adhered to the inner surface of the ring 81 between the two drive magnets. The driven magnet 82 is disposed between the drive magnets so that there is an axial overlap between the drive magnet and the driven magnet. The driven magnet is coupled to a pin 131 that extends beyond the distal end of the driven magnet 82, wherein the pin is coupled to the proximal end of the drive cable 130. For example, the driven magnet can be cylindrical and define a hole therethrough, and the pin 131 can be adhered to the inner surface of the driven magnet that defines the hole. For some applications, the driven magnet is cylindrical and the magnet includes a north pole and a south pole that are separated from each other along the length of the cylinder along a line 83 that bisects the cylinder, as shown. For some applications, the driven magnet is housed within a cylindrical housing 87. Typically, pin 131 defines a guidewire lumen 133 .

[0233] Note that in Figure 7 In the illustrated application, the drive magnet is disposed outside the driven magnet. However, the scope of the present application includes configurations in which the drive and driven magnets are reversed (mutatis mutandis). For example, the proximal end of the drive cable can be coupled to two or more driven magnets that are disposed around the drive magnet such that there is axial overlap between the driven and drive magnets.

[0234] As mentioned above, typically, the cleaning system 29 (e.g. Figure 1A86 and outlet port 88 for use with a purging system. For some applications, purging fluid is continuously or periodically pumped into the ventricular assist device via inlet port 86 and out of the ventricular assist device via outlet port 88.

[0235] Typically, the magnet 82 and the pin 131 are maintained in an axially fixed position within the motor unit 23. Typically, the proximal end of the drive cable is coupled to the pin 131 and is thereby maintained in an axially fixed position by the pin. Typically, the drive cable 130 extends from the pin 131 to the axial shaft 92 and thereby at least partially fixes the axial position of the axial shaft and, in turn, the impeller 50. For some applications, the drive cable is stretchable to some extent. For example, the drive cable can be made of a stretchable coiled wire. The drive cable typically allows the axial shaft (and, in turn, the impeller) to assume a range of axial positions (by subjecting the drive cable to more or less stretch), but limits the axial movement of the axial shaft and impeller to a certain range of motion (by maintaining the proximal end of the drive cable in an axially fixed position and limiting the stretchability of the drive cable).

[0236] As described above, for some applications, impeller 50 and axial shaft 92 are configured to reciprocate axially within frame 34 in response to forces acting on the impeller, without actively driving the axial shaft to move in an axially reciprocating motion. Typically, during a subject's cardiac cycle, the pressure differential between the left ventricle and the aorta varies from approximately zero during systole to a relatively large pressure differential (e.g., 50 mmHg-70 mmHg) during diastole. For some applications, because the pressure differential against which the impeller pumps increases during diastole (and because the drive cable is stretchable), the impeller is urged distally relative to frame 34 during diastole compared to its position relative to frame 34 during systole. Furthermore, because the impeller is connected to the axial shaft, the axial shaft moves forward. During systole, the impeller (and, therefore, the axial shaft) returns to its systolic position. In this way, the axial reciprocating motion of the impeller and the axial shaft is generated in a passive manner, ie, the axial shaft and the impeller do not need to be actively driven in order for them to undergo such motion.

[0237] Now refer to Figure 8A and Figure 8B , these figures are schematic diagrams of motor units 23 according to some applications of the present invention. In general, as Figure 8A and Figure 8B The motor unit 23 shown is similar to Figure 7 Motor units shown, unless otherwise stated, are Figure 8A and Figure 8BThe motor unit 23 shown comprises Figure 7 Components similar to the motor unit 23 shown are shown. For some applications, the motor unit includes a heat sink 90 configured to dissipate heat generated by the motor. Alternatively or additionally, the motor unit includes a vent port 93 configured to facilitate dissipation of heat generated by the motor. For some applications, the motor unit includes vibration dampers 94 and 96 configured to dampen vibrations of the motor unit caused by rotational motion and / or axial reciprocating motion of components of the ventricular assist device.

[0238] Now refer to Figure 9A and Figure 9B , which are schematic diagrams of a ventricular assist device 20 according to some applications of the invention, the device includes a liner 39 that lines the inside of a frame 34 that houses an impeller 50. For some applications, the liner 39 is disposed inside the frame 34 to provide a smooth inner surface (e.g., a smooth inner surface having a substantially circular cross-sectional shape) through which the impeller pumps blood. Typically, by providing a smooth surface, the covering material reduces hemolysis caused by the impeller pumping blood relative to pumping blood between the impeller and the struts of the frame 34. For some applications, the liner comprises polyurethane, polyester, and / or silicone. Alternatively or additionally, the liner comprises polyethylene terephthalate (PET) and / or polyether block amide

[0239] Typically, the liner is disposed over the inner surface of at least a portion of the central cylindrical portion 38 of the frame 34. For some applications, the pump outlet tube 24 also covers the central cylindrical portion 38 of the frame 34, e.g., around the outside of the frame, such that the pump outlet tube 24 and the liner 39 overlap over at least 50% of the length of the liner, e.g., over the entire length of the cylindrical portion of the frame 34, e.g., as shown in FIG. Figure 9A For some applications, there is only a partial overlap between the pump outlet tube 24 and the liner 39, e.g. Figure 9B As shown. For example, the pump outlet tube 24 can overlap the liner along less than 50% (e.g., less than 25%) of the length of the liner. For some such applications, during insertion of the ventricular assist device 20 into the subject, the impeller is advanced distally within the frame 34 such that the impeller is not positioned within the overlap region between the pump outlet tube and the liner, such that there is no longitudinal position in which the impeller, pump outlet tube 24, frame 34, and liner 39 all overlap one another. Figure 9A and Figure 9BAs shown, for some applications, a single axially facing blood inlet opening 108 is defined at the distal end of the pump outlet tube and / or liner. Alternatively, the liner is disposed on the inner surface of at least a portion of the central cylindrical portion 38 of the frame 34, and the pump outlet tube extends to the distal end of the frame and defines a plurality of lateral blood inlet openings 108. For example, in the following reference to Figures 11A-13B This application is described in further detail.

[0240] Typically, over the overlap region between the liner 39 and the pump outlet tube 24, the liner is shaped to form a smooth surface (e.g., to reduce hemolysis, as described above), and the pump outlet tube 24 is shaped to conform to the struts of the frame 34 (e.g., as described above). Figure 9A Furthermore, the liner typically has a substantially circular cross-section (e.g., due to the relatively small cell width within the central cylindrical portion of the frame, as described above with reference to Figure 2 For some applications, over the overlap region between liner 39 and pump outlet tube 24, the pump outlet tube and liner are coupled to one another, for example, via vacuum, via adhesive, and / or using a thermoforming process, as described below.

[0241] For some applications, the liner 39 and the pump outlet tube 24 are made of different materials from each other. For example, the liner can be made of polyurethane, while the pump outlet tube can be made of polyether block amide. Typically, for this application, the material from which the liner is made has a higher thermoforming temperature than the material from which the pump outlet tube is made. Optionally, the liner 39 and the pump outlet tube 24 are made from the same material as one another. For example, both the liner and the pump outlet tube may be made from polyurethane or polyether block amide. Made.

[0242] For some applications, the pump outlet pipe and the liner are bonded to each other and / or to the frame in the following manner. For some applications, the liner is bonded directly to the inner surface of the frame before the pump outlet pipe is bonded to the outside of the frame. Note that by bonding the liner directly to the inner surface of the frame (rather than simply bonding the liner to the pump outlet pipe, thereby sandwiching the frame between the liner and the pump outlet pipe), any bubbles, wrinkles and other discontinuities in smoothness of the surface provided by the liner are typically avoided. For some applications, techniques similar to those described above for enhancing the bond between the elastomeric membrane and the spiral elongated element of the impeller are used to enhance the bond between the liner and the inner surface of the frame. For some applications, initially, the frame is treated to enhance the bond between the liner and the inner surface of the frame. For some applications, treating the frame includes applying a plasma treatment to the frame (e.g., to an inner surface of the frame), immersing the frame in a coupling agent (e.g., a silane solution) having at least two functional groups configured to bond to the frame and the material from which the liner is made, respectively, and / or immersing the frame in a solution comprising the material from which the liner is made (e.g., a polyurethane solution). For some applications, the liner is made of an elastomeric material (e.g., polyurethane), and the coupling agent is a silane solution, such as a solution of n-(2-aminoethyl)-3-aminopropyltrimethoxysilane, wherein the silane comprises a first functional group (e.g., (OH)) configured to bond to the frame (which is typically made of an alloy such as Nitinol), and the silane comprises a second functional group (e.g., (NH2)) configured to bond to the elastomeric material.

[0243] For some applications, a solution containing the material from which the liner is made (e.g., a polyurethane solution) is then sprayed onto the central cylindrical portion of the cage. Once the inner surface of the frame has been treated, the liner is bonded to the inner surface of the central cylindrical portion of the frame (e.g., bonded to the inner surface of the central cylindrical portion of the frame). Typically, the liner (which is formed into a tube) is placed over the mandrel, the frame is placed over the liner, and pressure is applied through a heat shrink process. Furthermore, the liner and frame assembly is typically heated in an oven.

[0244] After the liner has been bonded to the frame, a portion of the pump outlet tube 24 is placed around the outside of the frame. As mentioned above, for some applications, the liner 39 and the pump outlet tube 24 are made of different materials from each other. For example, the liner can be made of polyurethane, while the pump outlet tube can be made of polyether block amide. Typically, for such applications, the liner is made of a material that has a higher thermoforming temperature than the material from which the pump outlet tube is made. For some applications, in order to mold the pump outlet tube 24 to conform to the struts of the frame 34 without deforming the liner, the frame is heated to a temperature that is higher than the thermoforming temperature of the pump outlet tube 24 but lower than the thermoforming temperature of the liner 39.

[0245] Typically, a mandrel is used to heat the frame from the inside of the frame. Typically, when the frame is heated to the above temperature, the outer tube (which is typically made of silicone) applies pressure to the pump outlet tube 24, causing the pump outlet tube 24 to be pushed radially inward so that the pump outlet tube conforms to the shape of the frame's struts, such as Figure 9A As shown in the cross section. For some applications, at this stage, the mandrel that is placed inside the liner and heats the liner is shorter than the length of the liner. The mandrel is typically placed inside the liner so that there is a margin on the outside of the mandrel at each end of the liner. Typically, the liner acts as a shield to prevent the pump outlet pipe from overheating and to prevent the pump outlet pipe from being damaged by the heating of the mandrel. Placing the liner on the mandrel in the manner described above prevents the mandrel from coming into direct contact with the frame and / or the pump outlet pipe. For some applications, the combination of the frame, the liner, and the portion of the pump outlet pipe 24 that is arranged around the frame is then shaped to the desired shape and size using shaping techniques known in the art.

[0246] Now refer to Figure 10A 、 Figure 10B and Figure 10C , these figures are schematic diagrams of a portion of a ventricular assist device 20 according to some applications of the present invention, the ventricular assist device including a protective braid 150 at its distal end. For some applications, the pump outlet tube 24 and the liner 39 extend to the end of the cylindrical portion 38 of the frame 34, as shown. Figures 10A-10C As shown. For some applications, in order to reduce the risk that structures from the left ventricle (e.g., chordae tendineae, chordae carnosus, and / or papillary muscles) may enter the frame 34 and potentially be damaged by the impeller and / or axial shaft and / or cause damage to the left ventricular assist device, the distal tapered portion 40 of the frame is covered (from the inside or outside) with a protective braid 150. Typically, the braid is embedded between the pump outlet tube and the liner within at least a portion of the cylindrical portion of the frame such that during crimping of the frame, the braid crimps with the pump outlet tube and the liner, thereby preventing the braid from moving relative to the pump outlet tube and / or the liner. (In Figures 10A-10C The area where the protective braid is embedded between the pump outlet tube and the liner is not visible because it is covered by the pump outlet tube.)

[0247] For some applications, the protective braid 150 extends substantially to the distal end of the distal tapered portion of the frame, e.g. Figure 10A For some such applications, along the distal portion 152 of the distal tapered portion of the frame, the braid is covered with a blood-impermeable material 154 (e.g., polyurethane, polyester, silicone, polyethylene terephthalate (PET), and / or polyether block amide (e.g., )),like Figure 10AAs shown. Typically, most of the blood flowing into the blood inlet opening 108 defined by the pump outlet tube comes from the sides of the distal tapered portion of the frame, and there is relatively little axial flow through the distal end of the distal tapered portion of the frame. Therefore, in some cases, there is a risk of stagnation in this area. In addition, the holes defined by the braid are typically smaller within the distal portion 152 of the distal tapered portion of the frame because the frame narrows. These two factors can cause thrombi to form on the braid within the distal portion 152 of the distal tapered portion of the frame. Therefore, for some applications, the braid is covered along the distal portion 152 of the distal tapered portion of the frame to prevent thrombi from forming on the braid within this portion. Typically, the braid is covered (e.g., with an elastomeric material that is impermeable to blood, such as polyurethane). Alternatively, the pattern of the braid does not extend to the distal end of the distal tapered portion of the frame. Instead, within the distal portion 152 of the distal tapered portion of the frame, the braid is opened or cut, for example to define large holes 156, as shown Figure 10B shown.

[0248] For some applications (not shown), the braid is covered (e.g., with an elastomeric material that is impermeable to blood, such as polyurethane) within the distal portion 152 of the distal tapered portion of the frame, and then a larger hole is cut from the covered braid. Alternatively or additionally (also not shown), the braid is covered with an elastomeric material that is impermeable to blood, such as polyurethane, within the distal portion 152 of the distal tapered portion of the frame, and then a hole is cut from the covered braid around the entire circumference of the frame, such that the covered braid defines a hole that extends around the entire circumference of the distal portion 152 of the distal tapered portion of the frame. For some such applications, the hole is cut so that it extends to the distal end of the distal tapered portion of the frame, i.e., so that there is a single hole that extends around the entire circumference of the frame and extends to the distal end of the distal tapered portion of the frame.

[0249] For some applications, the braid extends substantially to the distal end of the distal tapered portion of the frame, and the braid is not covered even within the distal portion 152 of the distal tapered portion of the frame, e.g. Figure 10C For some applications, the braid is woven into the struts of the distal tapered portion of the frame 34, as in Figure 10C shown in an enlarged view of the .

[0250] Now refer to Figures 11A-11D, these figures are schematic diagrams of a pump outlet tube 24 or a portion thereof according to some applications of the present invention, the pump outlet tube being configured to define a lateral blood inlet opening 108 at its distal end. For some applications, the pump outlet tube extends substantially to the distal end of the distal tapered portion 40 of the frame 34. For such applications, the pump outlet tube typically defines a distal tapered portion 46 that is distally facing, i.e., facing such that the narrow end of the cone is distal relative to the wide end of the cone. Typically, the pump outlet tube includes a coupling portion 41 (e.g., a tubular coupling portion, as shown) extending distally from the pump outlet tube. As described above, the coupling portion is coupled to the distal support housing to anchor the distal end of the pump outlet tube.

[0251] For some applications (not shown), the pump outlet tube defines two to four lateral blood inlet openings. Typically, for such applications, each blood inlet opening defines an area greater than 20 square millimeters (e.g., greater than 30 square millimeters), and / or less than 60 square millimeters (e.g., less than 50 square millimeters), such as 20-60 square millimeters, or 30-50 square millimeters. Alternatively or additionally, the outlet tube defines a greater number of smaller blood inlet openings 108, such as more than 10 blood inlet openings, more than 50 blood inlet openings, more than 100 blood inlet openings, or more than 150 blood inlet openings, such as 50-100 blood inlet openings, 100-150 blood inlet openings, or 150-200 blood inlet openings. For some applications, the blood inlet openings are sized so as to (a) allow blood to flow into the tube from the subject's left ventricle, and (b) prevent structures from the subject's left ventricle from entering the frame. Typically, for such applications, the distal tapered portion 46 of the pump outlet tube 24 is constructed to reduce the risk of structures from the left ventricle (e.g., chordae tendineae, chordae carnosus, and / or papillary muscles) entering the frame 34 and potentially being damaged by the impeller and / or axial shaft and / or causing damage to the left ventricular assist device. Thus, for some applications, the blood inlet openings are shaped such that in at least one direction, the width (or span) of the opening is less than 1 mm, e.g., 0.1 mm-1 mm or 0.3 mm-0.8 mm. By defining such a small width (or span), it is typically the case that structures from the left ventricle (e.g., chordae tendineae, chordae carnosus, and / or papillary muscles) are prevented from entering the frame 34. For some such applications, each blood inlet opening defines an area greater than 0.05 square millimeters (e.g., greater than 0.1 square millimeters) and / or less than 3 square millimeters (e.g., less than 1 square millimeter), e.g., 0.05 square millimeters-3 square millimeters or 0.1 square millimeters-1 square millimeter. Alternatively, each blood inlet opening defines an area greater than 0.1 mm2 (e.g., greater than 0.3 mm2) and / or less than 5 mm2 (e.g., less than 1 mm2), such as 0.1 mm2-5 mm2 or 0.3 mm2-1 mm2.

[0252] Typically, the portion of the pump outlet tube defining the blood inlet opening has a porosity greater than 40%, such as greater than 50%, or greater than 60% (where porosity is defined as the percentage of the area of ​​the portion that is porous for blood flow). Thus, on the one hand, the blood inlet opening is relatively small (to prevent structures of the left ventricle from entering the frame), but on the other hand, the porosity of the portion of the pump outlet tube defining the blood inlet opening is relatively high to allow sufficient blood to flow into the pump outlet tube.

[0253] For some applications, each blood inlet opening has a circular or polygonal shape. For some applications, each blood inlet opening has a hexagonal shape, such as Figures 11A-11D Typically, using openings having a hexagonal shape allows the portion of the pump outlet tubing defining the blood inlet opening to have a relatively high porosity (e.g., as described above) while providing the portion of the pump outlet tubing defining the blood inlet opening with sufficient material between the blood inlet openings to prevent tearing and / or stretching of the material. Figure 11B As shown, for some applications, the width W of the gap between adjacent hexagonal (or other polygonal) holes is greater than 0.01 mm (e.g., greater than 0.04 mm) and / or less than 0.1 mm (e.g., less than 0.08 mm), for example, 0.01 mm-0.1 mm, or 0.04 mm-0.08 mm. For some applications, the distance D between the opposite sides of each hexagon (or other type of polygon) is greater than 0.2 mm (e.g., greater than 0.4 mm) and / or less than 0.8 mm (e.g., less than 0.6 mm), for example, 0.2 mm-0.8 mm, or 0.4 mm-0.6 mm. Figure 11B As shown, typically each polygon encloses a circle (so that any structure that cannot pass through such a circle cannot pass through the polygon). Typically, the diameter of the circle enclosed by the polygon is equal to the distance D, for example, greater than 0.2 mm (for example, greater than 0.4 mm) and / or less than 0.8 mm (for example, less than 0.6 mm), for example 0.2 mm-0.8 mm, or 0.4 mm-0.6 mm.

[0254] Figure 11D A section of the distal tapered portion 46 of the pump outlet tube 24 is shown in accordance with some applications of the present invention. Figure 11D In the view shown, the section is unfolded and laid flat for illustration purposes. Figure 11DAs shown, for some applications, the width W1 of the gaps between the hexagonal (or other type of polygonal) holes in the proximal region 46P of the distal tapered portion 46 of the pump outlet tube 24 is greater than the width W of the gaps between the hexagonal (or other type of polygonal) holes in the distal region 46D of the distal tapered portion 46 of the pump outlet tube. For some applications, the ratio of the width of the gaps between adjacent blood inlet openings in the proximal region of the distal portion of the pump outlet tube to the width of the gaps between adjacent blood inlet openings in the distal region of the distal portion of the pump outlet tube is greater than 3:2, for example, between 3:2 and 5:2. Typically, for such applications, the distance D1 between opposing sides of each hexagon (or other type of polygonal) in the proximal region 46P of the distal tapered portion 46 of the pump outlet tube 24 is less than the distance D between opposing sides of each hexagon (or other type of polygonal) in the distal region 46D of the distal tapered portion 46 of the pump outlet tube. (As described above, distances D and D1 typically also represent the diameter of a circle enclosed by a polygon of corresponding size.) For some applications, the ratio of the diameter of the circle enclosed by each blood inlet opening in the distal region of the distal portion of the pump outlet tube to the diameter of the circle enclosed by each blood inlet opening in the proximal region of the distal portion of the pump outlet tube is greater than 7:6, e.g., between 7:6 and 4:3. Furthermore, the distal tapered portion of the pump outlet tube 24 typically has a higher porosity within the distal region 46D of the distal tapered portion 46 of the pump outlet tube than within the proximal region 46P of the distal tapered portion 46 of the pump outlet tube. For example, the ratio of the porosity within the distal region 46D to the porosity within the proximal region 46P is greater than 4:3 or greater than 3:2. For some applications, the proximal region extends along a length greater than 0.5 mm and / or less than 2 mm (e.g., less than 1.5 mm), e.g., between 0.5 mm and 2 mm or 0.5 mm and 1.5 mm. For some applications, the total length of the distal tapered portion is greater than 6 mm and / or less than 12 mm (eg, less than 10 mm), such as between 6 mm and 12 mm or 6 mm and 10 mm.

[0255] As mentioned above Figure 9A-9B As described above, the pump outlet tube is typically coupled to the frame 34 via heating. For some applications, the gaps between the blood inlet holes in the proximal region 46P of the distal tapered portion 46 of the pump outlet tube 24 are wider than the gaps between the blood inlet holes in the distal region 46D, and / or the blood inlet holes are smaller than the blood inlet holes in the distal region 46D, and / or the porosity is lower than the porosity in the distal region 46D, so as to prevent and / or reduce damage (e.g., tearing, thinning, and / or stretching) that may be caused to the material defining the blood inlet holes during the above-mentioned heating process.

[0256] Typically, the width W of the gaps between the hexagonal (or other type of polygonal) holes in the distal region 46D of the distal tapered portion 46 of the pump outlet tube and the distance D between the opposing sides of each hexagon (or other type of polygon) are as described above. For some applications, the width W1 of the gaps between adjacent hexagonal (or other polygonal) holes in the proximal region 46P of the distal tapered portion 46 of the pump outlet tube 24 is greater than 0.05 mm (e.g., greater than 0.07 mm) and / or less than 0.2 mm (e.g., less than 0.15 mm), for example, 0.05 mm to 0.2 mm, or 0.07 mm to 0.15 mm. For some applications, the distance D1 between opposing sides of each hexagon (or other type of polygon) within the proximal region 46P of the distal tapered portion 46 of the pump outlet tube 24 is greater than 0.1 mm (e.g., greater than 0.3 mm) and / or less than 0.6 mm (e.g., less than 0.5 mm), e.g., 0.1 mm-0.6 mm, or 0.3 mm-0.5 mm.

[0257] The scope of the present disclosure includes lateral blood inlet openings of non-uniform size and / or shape (e.g., circular, rectangular, polygonal, and / or hexagonal lateral blood inlet openings), arranged in any arrangement along the distal tapered portion 46 of the pump outlet tube. Similarly, the scope of the present disclosure includes the distal tapered portion 46 of the pump outlet tube defining lateral blood inlet openings, the lateral blood inlet openings being arranged such that the distal tapered portion has a non-uniform porosity, with the porosity varying between different regions of the distal tapered portion. For some applications, the shape and / or size of the lateral blood inlet openings, and / or the porosity of the distal tapered portion, vary to result in varying blood flow dynamics at different regions of the distal tapered portion. Alternatively or additionally, the shape and / or size of the lateral blood inlet openings, and / or the porosity of the distal tapered portion, vary to result in a varying shape of the distal tapered portion along its length.

[0258] Now refer to Figures 12A-12B , which is a schematic diagram of a pump outlet tube 24 or a portion thereof according to some applications of the present invention, the pump outlet tube being configured to define a lateral blood inlet opening 108 at its distal end. Figures 11A-11DAs described, for some applications, the pump outlet tube extends substantially to the distal end of the distal tapered portion 40 of the frame 34. For such applications, the pump outlet tube typically defines a distal tapered portion 46 that is distally facing, i.e., facing such that the narrow end of the cone is distal relative to the wide end of the cone. For some applications, the pump outlet tube defines more than 10 blood inlet openings, more than 50 blood inlet openings, more than 100 blood inlet openings, or more than 150 blood inlet openings, e.g., 50-100 blood inlet openings, 100-150 blood inlet openings, or 150-200 blood inlet openings. For some applications, the blood inlet openings are sized so as to (a) allow blood to flow into the tube from the subject's left ventricle, and (b) prevent structures from the subject's left ventricle from entering the frame. Typically, for such applications, the distal tapered portion 46 of the pump outlet tube 24 is constructed to reduce the risk of structures from the left ventricle (e.g., chordae tendineae, chordae carnosus, and / or papillary muscles) entering the frame 34 and potentially being damaged by the impeller and / or axial shaft and / or causing damage to the left ventricular assist device. Thus, for some applications, the blood inlet openings are shaped such that in at least one direction, the width (or span) of each opening is less than 1 mm, e.g., 0.1 mm-1 mm or 0.3 mm-0.8 mm. By defining such a small width (or span), it is typically the case that structures from the left ventricle (e.g., chordae tendineae, chordae carnosus, and / or papillary muscles) are prevented from entering the frame 34. For some such applications, each blood inlet opening defines an area greater than 0.05 square millimeters (e.g., greater than 0.1 square millimeters) and / or less than 3 square millimeters (e.g., less than 1 square millimeter), e.g., 0.05 square millimeters-3 square millimeters or 0.1 square millimeters-1 square millimeter. Alternatively, each blood inlet opening defines an area greater than 0.1 mm2 (e.g., greater than 0.3 mm2) and / or less than 5 mm2 (e.g., less than 1 mm2), such as 0.1 mm2-5 mm2 or 0.3 mm2-1 mm2.

[0259] For some applications, the blood inlet opening is generally defined as a rectangular shape, such as Figures 12A-12BAs shown. For some such applications, the ratio of the length to the width of the blood inlet opening is between 1.1:1 and 4:1, for example, between 3:2 and 5:2. For some applications, by having such a shape, the blood inlet opening is constructed to (a) prevent structures from the left ventricle (such as the chordae tendineae, sclera auricularis and / or papillary muscles) from entering the frame 34, but (b) provide the portion of the pump outlet tube defining the blood inlet opening with a relatively high porosity. Typically, the portion of the pump outlet tube defining the blood inlet opening has a porosity greater than 40%, such as greater than 50%, or greater than 60% (where porosity is defined as the percentage of the area of ​​the portion that is porous for blood flow). Thus, on the one hand, the blood inlet opening is relatively small (to prevent structures from the left ventricle from entering the frame), but on the other hand, the porosity of the portion of the pump outlet tube defining the blood inlet opening is relatively high to allow sufficient blood to flow into the pump outlet tube.

[0260] Typically, the pump outlet tube includes a coupling portion 41 (e.g., a tubular coupling portion, as shown) extending distally from the pump outlet tube. As described above, the coupling portion is coupled to the distal support housing 118H to anchor the distal end of the pump outlet tube. Also as described above, the pump outlet tube is typically coupled to the outside of the central cylindrical portion of the frame. For some applications, the distal tapered portion 46 of the pump outlet tube itself is not coupled to the distal tapered portion 40 of the frame. Instead, the distal tapered portion 46 of the pump outlet tube is held in place relative to the distal tapered portion 40 of the frame because the coupling portion 41 is coupled to the distal support housing 118H and the pump outlet tube is coupled to the outside of the central cylindrical portion of the frame. Alternatively, the distal tapered portion 46 of the pump outlet tube is directly coupled to the distal tapered portion 40 of the frame (e.g., via heat shrink).

[0261] As described above, for some applications, coupling portion 41 is coupled to an outer surface of portion 123 of distal support housing 118H. For some applications, coupling portion 41 defines aperture 111 (e.g., toward a distal end of the coupling portion), such as Figure 12B As shown. For some applications, adhesive is applied between the outer surface of the coupling portion 41 and the portion 123 of the distal support housing 118H via the hole. As described above, for some applications, the outer surface of the portion 123 of the distal support housing 118H is threaded. Typically, the threaded outer surface allows the adhesive to gradually and evenly diffuse between the coupling portion 41 and the outer surface of the portion 123 of the distal support housing 118H. In addition, the coupling portion is typically transparent so that the diffusion of the adhesive is visible through the coupling portion. Therefore, for some applications, once the adhesive is sufficiently diffused between the coupling portion 41 and the outer surface of the portion 123 of the distal support housing 118H (for example, once the outer surface of the portion 123 has been covered with adhesive), the application of the adhesive is terminated.

[0262] Note that the above description of methods and apparatus for coupling the distal tapered portion 46 of the pump outlet tube relative to other portions of the ventricular assist device applies to any embodiment of the distal tapered portion 46 of the pump outlet tube described herein, including those described with reference to Figures 11A-13B For some applications, similar techniques are used to attach the protective braid 150 (e.g. Figures 10A-10C shown) coupled to the distal support housing.

[0263] It should be noted that although the above description of methods and apparatus for coupling a connecting portion to a surface has been described with reference to the distal portion of the pump outlet tube and the outer surface of the distal support housing, similar apparatus and methods can be applied to any type of inlet guard (i.e., any element disposed above the distal tapered portion of the frame and defining a blood inlet opening sized so as to (a) allow blood to flow from the subject's left ventricle into the tube, and (b) prevent structures from the subject's left ventricle from entering the frame) and any surface disposed distal to the frame.

[0264] Now refer to Figures 13A-13B , which are schematic illustrations of a pump outlet tube 24 or portion thereof, configured to define a lateral blood inlet opening 108 at a distal end thereof, according to some applications of the present invention. Figures 13A-13B The pump outlet pipe 24 and Figures 12A-12B The pump outlet pipe shown in is generally similar except for the differences described below. Figure 10A As described, typically, the majority of the blood flow into the blood inlet opening 108 comes from the sides of the distal tapered portion of the frame, and there is relatively little axial flow through the distal end of the distal tapered portion of the frame. Therefore, in some cases, there is a risk of stagnation in this area, which may lead to thrombus formation within the distal end of the distal tapered portion of the frame. In addition, due to the lower blood flow, there is a lower risk of structures from the left ventricle (e.g., the chordae tendineae, sclera, and / or papillary muscles) entering the frame 34 through this area. Therefore, for some applications, the pump outlet tube 24 defines a large blood inlet opening 108L along the distal portion 158 of the distal tapered portion 46 of the pump outlet tube 24 (which typically covers the distal portion of the distal tapered portion of the frame), which reduces the risk of thrombus formation relative to a smaller blood inlet opening along the distal portion 158 of the distal tapered portion 46 of the pump outlet tube 24. (In some cases, the distal portion 158 corresponds to the distal region 46D, as shown in FIG. Figure 11D(As shown) Typically, the large blood inlet opening 108L has a trapezoidal or triangular shape. For some applications, the shape of the large blood inlet opening conforms to the shape of the frame struts within the distal portion of the frame. That is, the boundary 159 of the large blood inlet opening is located along the struts of the distal portion of the frame, and the opening itself is located above the opening defined by the struts. For some applications, there are 4 to 12 (e.g., 6 to 10) large blood inlet openings. Typically, each large blood inlet opening has an area of ​​1-7 square millimeters, such as 2-5 square millimeters or 3-4 square millimeters. For some applications, the ratio of the area of ​​the smallest of the large blood inlet openings 108L to the largest of the smaller blood inlet openings 108 is greater than 3:1, such as greater than 4:1. Typically, within the distal portion 158 of the distal tapered portion 46 of the pump outlet tube 24, the tube 24 has a porosity greater than 55%, such as greater than 65%.

[0265] Now refer to Figure 14A and Figure 14B , Figure 14A and Figure 14B FIG2 is a schematic diagram of a frame 34 of a ventricular assist device 20 according to some applications of the present invention, the frame including a protective braid 155 at its proximal end. For some applications, the protective braid is disposed over (or within) the proximal tapered section of the frame 34. For example, the protective braid may be disposed in a manner similar to that of reference 154. Figure 10C Typically, the protective braid is configured to act as a filter, for example by preventing any elements (e.g., thrombi) larger than a given size from migrating proximally along the pump outlet tube 24. The protective braid may be used in conjunction with any of the embodiments described herein. For example, the protective braid may be used in conjunction with a braid defining a single axially facing blood inlet opening 108 (e.g., Figure 14A ) can be used with a pump outlet tube, or a protective braid can be used with a pump outlet tube defining a lateral blood inlet opening 108 (as shown). Figure 14B For use with pump outlet tubing (as shown).

[0266] Now refer to Figure 15, which is a schematic diagram of a pump outlet tube 24 defining a blood outlet opening 109 at its proximal end, according to some applications of the present invention. For some applications, the blood outlet opening is sized and shaped similarly to the shape and size of any of the embodiments of the lateral blood inlet opening 108 described herein. For some applications, by having such a shape, the area of ​​the pump outlet tube defining the blood outlet opening is configured to (a) act as a filter, e.g., by preventing any elements (e.g., thrombi) larger than a given size from migrating proximally from the pump outlet tube 24, and also (b) provide the portion of the pump outlet tube defining the blood outlet opening with a relatively high porosity. Typically, the portion of the pump outlet tube defining the blood inlet opening has a porosity greater than 40%, e.g., greater than 50%, or approximately 60% (where porosity is defined as the percentage of the area of ​​the portion that is porous to blood flow). Thus, on the one hand, the blood outlet opening is relatively small (so as to prevent any elements (e.g., thrombi) larger than a given size from migrating proximally from the pump outlet tube 24), but on the other hand, the porosity of the portion of the pump outlet tube defining the blood outlet opening is relatively high, e.g., to allow sufficient blood flow from the pump outlet tube. Figure 15 The blood outlet opening shown can be used in conjunction with any of the embodiments described herein. Figure 15 The blood outlet opening shown may be used to define a single axially facing blood inlet opening 108 (e.g., Figure 15 The blood outlet opening may be a portion of a pump outlet tube defining a lateral blood inlet opening 108 (combination not shown), or the blood outlet opening may be a portion of a pump outlet tube defining a lateral blood inlet opening 108 (combination not shown).

[0267] About Reference Figures 1A-15 All aspects of the ventricular assist device 20 described should be noted that although Figure 1A and Figure 1BA ventricular assist device 20 is shown in the left ventricle of a subject, but for some applications, the ventricular assist device 20 is placed in the right ventricle of the subject such that the device passes through the subject's pulmonary valve, and the techniques described herein are applied (mutatis mutandis). For some applications, components of the device 20 are applicable to different types of blood pumps. For example, aspects of the present invention may be applicable to a pump that is used to pump blood from the vena cava and / or right atrium into the right ventricle, from the vena cava and / or right atrium into the pulmonary artery, and / or from the renal vein into the vena cava. These aspects may include features of the tube 24 (e.g., the curvature of the tube), the impeller 50, features of the pump head portion 27, the drive cable 130, and the like. Alternatively or additionally, the device 20 and / or a portion thereof (e.g., the impeller 50, even without the tube 24) may be placed in a different part of the subject's body to assist in pumping blood from that part. For example, the device 20 and / or a portion thereof (e.g., the impeller 50, even without the tube 24) may be placed in a blood vessel and may be used to pump blood through the blood vessel. For some applications, device 20 and / or portions thereof (e.g., impeller 50, even without tube 24) are configured (mutatis mutandis) for placement within the subclavian vein or jugular vein, at the junction of the vein with the lymphatic vessels, and for increasing the flow of lymphatic fluid from the lymphatic vessels into the vein. Because the scope of the present invention includes use of the apparatus and methods described herein at anatomical locations other than the left ventricle and aorta, ventricular assist devices and / or portions thereof are sometimes referred to herein (in the specification and claims) as blood pumps.

[0268] The scope of the present invention includes combining any of the apparatus and methods described herein with any of the apparatus and methods described in one or more of the following applications, all of which are incorporated herein by reference:

[0269] Tuval’s US 17 / 609,589, which is the U.S. national phase of PCT Application No. PCT / IB2021 / 052857, filed by Tuval on April 6, 2021, entitled “Ventricular assist device” (published as WO 21 / 205346), which claims priority to:

[0270] U.S. Provisional Patent Application No. 63 / 006,122, filed by Tuval on April 7, 2020, entitled “Ventricular assist device”;

[0271] U.S. Provisional Patent Application 63 / 114,136, filed by Tuval on November 16, 2020, entitled “Ventricular assist device”; and

[0272] Tuval’s U.S. provisional patent application 63 / 129,983, titled “Ventricular assist device,” filed on December 23, 2020.

[0273] Tuval, filed January 23, 2020, US 2020 / 0237981, entitled “Distal tip element for a ventricular assist device,” claims priority to:

[0274] U.S. Provisional Patent Application 62 / 796,138, filed by Tuval on January 24, 2019, entitled “Ventricular assist device”;

[0275] U.S. Provisional Patent Application 62 / 851,716, filed by Tuval on May 23, 2019, entitled “Ventricular assist device”;

[0276] U.S. Provisional Patent Application No. 62 / 870,821, filed by Tuval on July 5, 2019, entitled “Ventricular assist device”; and

[0277] Tuval, U.S. Provisional Patent Application 62 / 896,026, filed on September 5, 2019, entitled “Ventricular assist device.”

[0278] US 2019 / 0209758 to Tuval, which is a continuation of International Application No. PCT / IB2019 / 050186 filed on January 10, 2019 by Tuval and entitled “Ventricular assist device” (published as WO 19 / 138350), which claims priority to:

[0279] U.S. Provisional Patent Application 62 / 615,538, filed by Sohn on January 10, 2018, entitled “Ventricular assist device”;

[0280] U.S. Provisional Patent Application No. 62 / 665,718, filed by Sohn on May 2, 2018, entitled “Ventricular assist device”;

[0281] U.S. Provisional Patent Application No. 62 / 681,868, filed by Tuval on June 7, 2018, entitled “Ventricular assist device”; and

[0282] U.S. Provisional Patent Application No. 62 / 727,605, filed by Tuval on September 6, 2018, entitled “Ventricular assist device”;

[0283] Tuval’s US 2019 / 0269840, which is the U.S. national phase application of Tuval’s international patent application PCT / IL2017 / 051273, filed on November 21, 2017 (published as WO 18 / 096531), entitled “Blood pumps,” which claims priority to Tuval’s U.S. provisional patent application No. 62 / 425,814, filed on November 23, 2016;

[0284] US 2019 / 0175806 to Tuval, which is a continuation of International Application No. PCT / IL2017 / 051158 filed by Tuval on October 23, 2017, entitled “Ventricular assist device,” published as WO 18 / 078615, which claims priority to US 62 / 412,631 filed by Tuval on October 25, 2016, and US 62 / 543,540 filed by Tuval on August 10, 2016;

[0285] Tuval’s US 2019 / 0239998, which is the U.S. national phase application of Tuval’s international patent application PCT / IL2017 / 051092, filed on September 28, 2017 (published as WO 18 / 061002), entitled “Blood vessel tube,” which claims priority to Tuval’s U.S. provisional patent application No. 62 / 401,403, filed on September 29, 2016;

[0286] US 2018 / 0169313 to Schwammenthal, which is the U.S. national phase application of Schwammenthal’s international patent application PCT / IL2016 / 050525, filed on May 18, 2016, and entitled “Blood pump,” published as WO 16 / 185473, which claims priority to U.S. provisional patent application 62 / 162,881, filed on May 18, 2015, and entitled “Blood pump”;

[0287] US 2017 / 0100527 to Schwammenthal, which is the U.S. national phase of Schwammenthal’s international patent application PCT / IL2015 / 050532, filed on May 19, 2015, and entitled “Blood pump,” published as WO 15 / 177793, which claims priority to U.S. provisional patent application 62 / 000,192, filed on May 19, 2014, and entitled “Blood pump”;

[0288] US 10,039,874 to Schwammenthal, which is the U.S. national phase of Schwammenthal’s international patent application PCT / IL2014 / 050289, filed on March 13, 2014, and entitled “Renal pump,” published as WO 14 / 141284, which claims priority to (a) Schwammenthal’s U.S. provisional patent application 61 / 779,803, filed on March 13, 2013, and entitled “Renal pump,” and (b) Schwammenthal’s U.S. provisional patent application 61 / 914,475, filed on December 11, 2013, and entitled “Renal pump”;

[0289] U.S. Patent No. 9,764,113, entitled “Curved catheter,” issued to Tuval on September 19, 2017, which claims priority to U.S. Provisional Patent Application No. 61 / 914,470, filed by Tuval on December 11, 2013, entitled “Curved catheter”; and

[0290] Tuval’s US 9,597,205 is the U.S. national phase of Tuval’s international patent application PCT / IL2013 / 050495, filed on June 6, 2013, entitled “Prosthetic renal valve,” published as WO 13 / 183060, which claims priority to Tuval’s U.S. provisional patent application 61 / 656,244, filed on June 6, 2012, entitled “Prosthetic renal valve.”

[0291] Those skilled in the art will recognize that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications of the present invention that are not in the prior art and that would occur to those skilled in the art upon reading the foregoing description.

[0292] This application also provides the following aspects:

[0293] 1) A device comprising:

[0294] A left ventricular assist device, comprising:

[0295] an impeller configured to be placed within a left ventricle of a subject and configured to pump blood from the left ventricle of the subject to an aorta of the subject by rotation;

[0296] a frame disposed about the impeller, the frame including a plurality of strut junctions at a proximal end of the frame, the strut junctions being configured to remain in an open position during assembly of the left ventricular assist device to facilitate insertion of the impeller into the frame;

[0297] a securing element configured to maintain the strut joint in a closed state after the impeller is inserted into the frame; and

[0298] a pump outlet tube configured to pass through an aortic valve of a subject such that a proximal portion of the pump outlet tube is disposed within the subject's aorta and a distal portion of the pump outlet tube is disposed within the subject's left ventricle, the distal portion of the pump outlet tube extending to a distal end of the frame and defining one or more lateral blood inlet openings configured to allow blood to flow from the subject's left ventricle into the pump outlet tube.

[0299] 2) The apparatus according to 1), wherein the fixing element comprises a ring.

[0300] 3) The apparatus according to 1), wherein the left ventricular assist device includes a portion distal to the frame, and wherein the pump outlet tube further comprises a coupling portion extending distally from the frame and coupled to the portion of the left ventricular assist device distal to the frame.

[0301] 4) The apparatus of any one of 1) to 3), wherein the distal portion of the pump outlet tube defines more than 10 blood inlet openings, the blood inlet openings being sized to (a) allow blood to flow from the subject's left ventricle into the tube, and (b) prevent structures from the subject's left ventricle from entering the frame.

[0302] 5) The apparatus of 4) wherein the distal portion of the pump outlet tube defines more than 50 blood inlet openings sized to (a) allow blood to flow into the tube from the subject's left ventricle, and (b) prevent structures from the subject's left ventricle from entering the frame.

[0303] 6) The apparatus according to 1) or 2), wherein the left ventricular assist device further comprises:

[0304] a proximal radial support disposed within a proximal support housing at a proximal end of the frame;

[0305] a distal radial support disposed within a distal support housing at a distal end of the frame;

[0306] an axial shaft on which the impeller is arranged, the axial shaft passing through the proximal radial support and the distal radial support,

[0307] Wherein the fixation element is configured to maintain the strut junction closed about an outer surface of the proximal support housing.

[0308] 7) The apparatus of 6), wherein the pump outlet tube further includes a coupling portion extending distally from the frame and coupled to the distal support housing.

[0309] 8) The apparatus of 6) wherein a distal end of the frame is coupled to an outer surface of the distal support housing.

[0310] 9) The apparatus of 6) wherein the left ventricular assist device further comprises a distal tip element, and wherein the distal tip element is coupled to the distal support housing.

[0311] 10) The apparatus of 6) wherein the outer surface of the proximal support housing defines a recess shaped to receive the strut engagement portion.

[0312] 11) The apparatus of 10) wherein the post engaging portion defines a widened head portion, and wherein the recess is shaped to conform to the widened head portion of the post engaging portion.

[0313] 12) The apparatus of 6) wherein the proximal radial support and the distal radial support are made of a ceramic material, and the proximal support housing and the distal support housing are made of a second material that can be molded into a desired shape.

[0314] 13) The apparatus according to 12), wherein the proximal support housing and the distal support housing are made of metal and / or alloy.

[0315] 14) The apparatus of 13), wherein the axial shaft comprises a metal and / or alloy, and wherein the axial shaft is covered with a ceramic sleeve in an area along the axial shaft that contacts either the proximal support or the distal support during operation of the left ventricular assist device.

[0316] 15) A method of manufacturing a left ventricular assist device, the method comprising:

[0317] forming a frame such that the frame is closed at a distal end thereof and such that a plurality of strut joints at a proximal end of the frame remain in an open state;

[0318] coupling a pump outlet tube to the frame such that a distal portion of the pump outlet tube extends to a distal end of the frame and the distal portion of the pump outlet tube defines one or more lateral blood inlet openings configured to allow blood to flow from the left ventricle of the subject into the pump outlet tube, the pump outlet tube being configured to pass through an aortic valve of the subject such that a proximal portion of the pump outlet tube is disposed within the aorta of the subject and the distal portion of the pump outlet tube is disposed within the left ventricle of the subject;

[0319] inserting an impeller into the frame via the proximal end of the frame, the impeller configured to pump blood through the pump outlet tube by rotation; and

[0320] The strut joint at the proximal end of the frame is then closed and retained in its closed state using a fixation element.

[0321] 16) The method according to 15), wherein the fixing element includes a ring, and using the fixing element to maintain the strut joint in the closed state of the strut joint includes using the ring to maintain the strut joint in the closed state of the strut joint.

[0322] 17) The method according to 15), wherein the pump outlet tube further comprises a connecting portion configured to extend distally from the frame, wherein the method further comprises connecting the connecting portion to a portion of the left ventricular assist device located distally from the frame.

[0323] 18) The method according to 15) or 16), wherein the left ventricular assist device further comprises:

[0324] a proximal radial support disposed within a proximal support housing at a proximal end of the frame;

[0325] a distal radial support disposed within a distal support housing at a distal end of the frame;

[0326] an axial shaft on which the impeller is arranged, the axial shaft passing through the proximal radial support and the distal radial support,

[0327] Wherein maintaining the strut joint in the closed state at the strut joint using the fixation element includes maintaining the strut joint in the closed state at the strut joint by maintaining the strut joint closed about an outer surface of the proximal support housing.

[0328] 19) The method according to 18), wherein the pump outlet tube further comprises a coupling portion configured to extend distally from the frame, wherein the method further comprises coupling the coupling portion to the distal support housing.

[0329] 20) The method of 18) further comprising coupling a distal end of the frame to an outer surface of the distal support housing.

[0330] 21) The method of 18) further comprising coupling a distal tip element to the distal support housing.

[0331] 22) A method according to 18), wherein the outer surface of the proximal support shell defines a groove, the groove being shaped to receive the strut joint, and wherein maintaining the strut joint closed around the outer surface of the proximal support shell includes maintaining the strut joint within the groove defined by the outer surface of the proximal support shell.

[0332] 23) The method of 22), wherein the strut joint defines a widened head, and wherein retaining the strut joint within the groove defined by the outer surface of the proximal support shell includes retaining the strut joint within a groove shaped to be consistent with the widened head of the strut joint.

[0333] 24) The method according to 18), wherein the proximal radial support and the distal radial support are made of a ceramic material, and the proximal support housing and the distal support housing are made of a second material that can be molded into a desired shape.

[0334] 25) The method according to 24), wherein the proximal support housing and the distal support housing are made of metal and / or alloy.

[0335] 26) The method according to 25), wherein the axial shaft comprises metal and / or alloy, and wherein the method further comprises covering the axial shaft with a ceramic sleeve along an area of ​​the axial shaft that contacts either the proximal support and the distal support during operation of the left ventricular assist device.

[0336] 27) A device comprising:

[0337] A left ventricular assist device, comprising:

[0338] an impeller configured to be placed within a left ventricle of a subject and configured to pump blood from the left ventricle of the subject to an aorta of the subject by rotation;

[0339] a frame disposed around the impeller; and

[0340] a pump outlet tube configured to pass through the aortic valve of the subject such that a proximal portion of the tube is disposed within the subject's aorta and a distal portion of the pump outlet tube is disposed within the subject's left ventricle,

[0341] the distal portion of the pump outlet tube extending to the distal end of the frame and defining more than ten blood inlet openings sized to (a) permit blood to flow from the subject's left ventricle into the tube, and (b) prevent structures from the subject's left ventricle from entering the frame,

[0342] The porosity of the distal portion of the pump outlet tube, which defines the blood inlet opening, is lower in a proximal region of the distal portion of the pump outlet tube than in a distal region of the distal portion of the pump outlet tube located distal to the proximal region.

[0343] 28) The apparatus according to 27), wherein each of the blood inlet openings is shaped so that in at least one direction the width of the opening is less than 1 mm.

[0344] 29) The apparatus according to 27), wherein the ratio of the porosity of the distal portion of the pump outlet tube in the distal region to the porosity of the distal portion of the pump outlet tube in the proximal region is greater than 4:3.

[0345] 30) The device according to 27), wherein the porosity of the distal portion of the pump outlet tube varies between the proximal region and the distal region to result in varying hemodynamics at different regions of the distal portion of the pump outlet tube.

[0346] 31) The apparatus of 27), wherein the distal portion of the pump outlet tube is tapered, and wherein the porosity of the distal portion of the pump outlet tube varies between the proximal region and the distal region to cause the shape of the distal tapered portion to vary along its length.

[0347] 32) The apparatus according to 27), wherein the pump outlet tube defines a large blood inlet opening along the distal region of the distal portion of the pump outlet tube, and the large blood inlet opening is configured to reduce the risk of thrombosis relative to a smaller blood inlet opening along the distal region of the distal tapered portion of the pump outlet tube.

[0348] 33) The apparatus of 27) wherein the distal portion of the pump outlet tube defines more than 50 blood inlet openings sized to (a) allow blood to flow from the subject's left ventricle into the tube, and (b) prevent structures from the subject's left ventricle from entering the frame.

[0349] 34) The apparatus according to 27), wherein the blood inlet openings are rectangular and shaped so that the ratio of the length to the width of each of the blood inlet openings is between 1.1:1 and 4:1.

[0350] 35) The apparatus according to 27), wherein the blood inlet openings are rectangular and shaped so that the ratio of the length to the width of each of the blood inlet openings is between 3:2 and 5:2.

[0351] 36) The apparatus according to any one of 27) to 35), wherein the distal portion of the pump outlet tube has a porosity greater than 40%.

[0352] 37) The device according to 36), wherein the distal portion of the pump outlet tube has a porosity greater than 50%.

[0353] 38) The device according to 37), wherein the distal portion of the pump outlet tube has a porosity greater than 60%.

[0354] 39) An apparatus according to any one of 27)-35), wherein the frame defines a central cylindrical portion and a distal conical portion, wherein the distal portion of the pump outlet tube defining the blood inlet opening is conical and disposed on the distal conical portion of the frame, and wherein a portion of the pump outlet tube adjacent to the distal portion of the pump outlet tube is coupled to the central cylindrical portion of the frame.

[0355] 40) The apparatus of claim 39), wherein the portion of the pump outlet tube proximal to the distal portion of the pump outlet tube is coupled to the central cylindrical portion of the frame by heating, and wherein the porosity in the proximal region of the distal portion of the pump outlet tube is lower, thereby reducing potential damage to the material defining the blood inlet hole in the proximal region of the distal portion of the pump outlet tube during heating relative to a higher porosity in the proximal region of the distal portion of the pump outlet tube.

[0356] 41) The apparatus according to 39) further comprises an inner liner coupled to the inner surface of the central cylindrical portion of the frame such that the inner liner provides a smooth inner surface for the central cylindrical portion of the frame.

[0357] 42) The device according to 39), wherein the proximal region of the distal portion of the pump outlet tube extends along a length of 0.5 mm - 2 mm.

[0358] 43) The device according to any one of 27) to 35), wherein the blood inlet opening has a polygonal shape.

[0359] 44) The device according to 43), wherein the blood inlet opening has a hexagonal shape.

[0360] 45) The device according to 43), wherein, in the proximal region of the distal portion of the pump outlet tube, the diameter of the circle enclosed by each of the blood inlet openings is between 0.1 mm and 0.6 mm.

[0361] 46) The device according to 43), wherein in the proximal region of the distal portion of the pump outlet tube, the width of the gap between adjacent blood inlet openings is between 0.05 mm and 0.2 mm.

[0362] 47) The device according to 43), wherein, in the distal region of the distal portion of the pump outlet tube, the diameter of the circle enclosed by each of the blood inlet openings is between 0.2 mm and 0.8 mm.

[0363] 48) The apparatus according to 43), wherein in the distal region of the distal portion of the pump outlet tube the width of the gaps between adjacent blood inlet openings is between 0.01 mm and 0.1 mm.

[0364] 49) The device according to 43), wherein the ratio of the diameter of the circle enclosed by each of the blood inlet openings in the distal region of the distal portion of the pump outlet tube to the diameter of the circle enclosed by each of the blood inlet openings in the proximal region of the distal portion of the pump outlet tube is greater than 7:6.

[0365] 50) The device according to 43), wherein the ratio of the width of the gap between adjacent blood inlet openings in the proximal region of the proximal portion of the pump outlet tube to the width of the gap between adjacent blood inlet openings in the distal region of the distal portion of the pump outlet tube is greater than 3:2.

[0366] 51) A method comprising:

[0367] The housing for the impeller of the blood pump is manufactured by the following steps:

[0368] treating the frame to enhance the bond between the inner surface of the frame and the lining;

[0369] subsequently coupling the liner to the inner surface of the frame along at least a portion of a central cylindrical portion of the frame, the central cylindrical portion of the frame including struts defining a generally cylindrical shape;

[0370] After coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame:

[0371] placing a mandrel inside the liner;

[0372] placing a portion of an elongated tube around at least a portion of the frame, the elongated tube including a proximal portion, the proximal portion of the elongated tube defining at least one blood outlet opening;

[0373] heating the liner, the frame, and the portion of the elongated tube via the mandrel while the portion of the elongated tube is disposed around at least the portion of the frame; and

[0374] While heating the liner, the frame, and the portion of the elongated tube, pressure is applied from outside the portion of the elongated tube to couple the portion of the elongated tube to the frame.

[0375] 52) The method of 51), wherein the struts of the central cylindrical portion of the frame define cells, and the cells are configured such that in a non-radially constrained configuration of the frame, the width of each of the cells within the central cylindrical portion of the frame as measured around the circumference of the central cylindrical portion of the frame is less than 2 mm.

[0376] 53) The method of 51), wherein, while heating the liner, the frame, and the portion of the elongated tube, applying pressure from outside the portion of the elongated tube includes conforming the portion of the elongated tube to the structure of the struts of the frame.

[0377] 54) The method of 51), wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame comprises coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner has a substantially circular cross-section.

[0378] 55) The method of 51), wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame comprises coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner provides a smooth inner surface to the portion of the central cylindrical portion of the frame to which the liner is coupled.

[0379] 56) The method of 51) wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes avoiding bubbles, wrinkles, and other discontinuities in smoothness of the surface provided by the liner.

[0380] 57) The method according to 51), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises applying a plasma treatment to the frame.

[0381] 58) The method of 51), wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame comprises:

[0382] placing the liner over a mandrel;

[0383] placing the frame over the liner; and

[0384] Pressure is applied via a heat shrink process.

[0385] 59) A method according to any one of 51) to 58), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises immersing the frame in a solution containing a material from which the lining is made.

[0386] 60) The method of 59), wherein the lining comprises polyurethane, and wherein immersing the frame in the solution comprises immersing the frame in a polyurethane solution.

[0387] 61) A method according to any one of 51)-58), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises spraying the inner surface of the portion of the central cylindrical portion of the frame with a solution containing a material for making the lining.

[0388] 62) The method of 61), wherein the lining comprises polyurethane, and wherein spraying the inner surface of the portion of the central cylindrical portion of the frame comprises spraying the inner surface of the portion of the central cylindrical portion of the frame with a polyurethane solution.

[0389] 63) A method according to any one of 51)-58), wherein, after connecting the liner to the inner surface of the frame along at least the portion of the central cylindrical portion of the frame, placing the core shaft within the liner includes placing a core shaft that is shorter than the length of the liner on the inside of the liner.

[0390] 64) The method of 63), wherein, after coupling the liner to the inner surface of the frame along at least the portion of the central cylindrical portion of the frame, placing the mandrel within the liner includes placing the mandrel within the liner such that a margin is left outside the mandrel at each end of the liner.

[0391] 65) The method according to 64), wherein placing the core shaft within the liner so that a margin is left outside the core shaft at each end of the liner includes preventing the core shaft from directly contacting the frame or the pump outlet pipe, thereby preventing the pump outlet pipe from overheating and preventing the pump outlet pipe from being damaged by heating of the core shaft.

[0392] 66) A method according to any one of 51) to 58), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises immersing the frame in a coupling agent having at least two functional groups, wherein the at least two functional groups are configured to bond to the frame and the material from which the lining is made, respectively.

[0393] 67) The method of 66), wherein the lining comprises polyurethane, and wherein immersing the frame in the coupling agent comprises immersing the frame in a silane solution.

[0394] 68) A method comprising:

[0395] The housing for the impeller of the blood pump is manufactured by the following steps:

[0396] placing a mandrel inside a liner with a central cylindrical portion of a frame disposed around the liner, the central cylindrical portion of the frame including struts defining a generally cylindrical shape,

[0397] wherein the mandrel is shorter than the length of the liner;

[0398] placing a portion of an elongated tube around at least a portion of the frame, the elongated tube including a proximal portion, the proximal portion of the elongated tube defining at least one blood outlet opening;

[0399] heating the liner, the frame, and the portion of the elongated tube via the mandrel while the portion of the elongated tube is disposed around at least the portion of the frame; and

[0400] While heating the liner, the frame, and the portion of the elongated tube, pressure is applied from outside the portion of the elongated tube to couple the portion of the elongated tube to the frame.

[0401] 69) A method according to 68), wherein the struts of the central cylindrical portion of the frame define cells, and the cells are constructed so that in a non-radially constrained configuration of the frame, the width of each of the cells within the central cylindrical portion of the frame as measured around the circumference of the central cylindrical portion of the frame is less than 2 mm.

[0402] 70) The method of 68) wherein, while heating the liner, the frame, and the portion of the elongated tube, applying pressure from outside the portion of the elongated tube includes conforming the portion of the elongated tube to the structure of the struts of the frame.

[0403] 71) The method according to any one of 68)-70), wherein placing the mandrel inside the liner includes placing the mandrel inside the liner so that a margin is left outside the mandrel at each end of the liner.

[0404] 72) The method according to 71), wherein placing the core shaft within the liner so that a margin is left outside the core shaft at each end of the liner includes preventing the core shaft from directly contacting the frame or the pump outlet pipe, thereby preventing the pump outlet pipe from overheating and preventing the pump outlet pipe from being damaged by heating of the core shaft.

[0405] 73) The method according to any one of 68) to 70) further comprises, before placing the mandrel in the liner:

[0406] treating the frame to enhance the bond between the inner surface of the frame and the liner; and

[0407] The liner is coupled to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame.

[0408] 74) The method of 73), wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner has a substantially circular cross-section.

[0409] 75) The method of 73), wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame comprises coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame such that the liner provides a smooth inner surface to the portion of the central cylindrical portion of the frame to which the liner is coupled.

[0410] 76) The method of 73) wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame includes avoiding bubbles, wrinkles, and other discontinuities in smoothness of the surface provided by the liner.

[0411] 77) The method according to 73), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises applying a plasma treatment to the frame.

[0412] 78) The method of 73), wherein coupling the liner to the inner surface of the frame along at least a portion of the central cylindrical portion of the frame comprises:

[0413] placing the liner over a mandrel;

[0414] placing the frame over the liner; and

[0415] Pressure is applied via a heat shrink process.

[0416] 79) The method of 73) wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises immersing the frame in a solution containing the material from which the lining is made.

[0417] 80) The method of claim 79), wherein the lining comprises polyurethane, and wherein immersing the frame in the solution comprises immersing the frame in a polyurethane solution.

[0418] 81) A method according to 73), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining includes spraying the inner surface of the portion of the central cylindrical portion of the frame with a solution containing a material for making the lining.

[0419] 82) The method of 81), wherein the lining comprises polyurethane, and wherein spraying the inner surface of the portion of the central cylindrical portion of the frame comprises spraying the inner surface of the portion of the central cylindrical portion of the frame with a polyurethane solution.

[0420] 83) A method according to 73), wherein treating the frame to enhance the bond between the inner surface of the frame and the lining comprises immersing the frame in a coupling agent having at least two functional groups, wherein the at least two functional groups are configured to bond to the frame and the material of which the lining is made, respectively.

[0421] 84) The method of 83), wherein the lining comprises polyurethane, and wherein immersing the frame in the coupling agent comprises immersing the frame in a silane solution.

[0422] 85) A device comprising:

[0423] A left ventricular assist device, comprising:

[0424] an impeller configured to be placed within a left ventricle of a subject and configured to pump blood from the left ventricle of the subject to an aorta of the subject by rotation;

[0425] a frame disposed about the impeller, the frame defining a distal tapered portion;

[0426] a surface disposed distally of the frame; and

[0427] an inlet guard disposed over the distal tapered portion of the frame, the inlet guard:

[0428] defining a blood inlet opening sized to (a) allow blood to flow from the subject's left ventricle into the tube and (b) prevent structures from the subject's left ventricle from entering the frame, and

[0429] A distal coupling portion is configured to couple to the surface disposed distally of the frame and defines an aperture configured to facilitate application of an adhesive between the distal coupling portion and the surface disposed distally of the frame.

[0430] 86) The apparatus of 85), wherein the inlet guard comprises a distal portion of a pump outlet tube configured to pass through an aortic valve of the subject such that the proximal portion of the pump outlet tube is disposed within the subject's aorta and the distal portion of the pump outlet tube is disposed within the subject's left ventricle.

[0431] 87) The apparatus according to 85), wherein the surface provided distal to the frame is ridged to enhance bonding between the surface and the coupling portion.

[0432] 88) The apparatus of 85) wherein the surface disposed distally from the frame is threaded to allow the adhesive to gradually and evenly diffuse between the coupling portion and the surface.

[0433] 89) The apparatus according to 85), wherein the connecting portion is tubular.

[0434] 90) Apparatus according to 85) wherein the coupling portion is transparent so that diffusion of adhesive between the coupling portion and the surface is visible.

[0435] 91) The apparatus according to any one of 85) to 90), wherein the left ventricular assist device further comprises:

[0436] a proximal radial support disposed within a proximal support housing at a proximal end of the frame;

[0437] a distal radial support disposed within a distal support housing at a distal end of the frame;

[0438] an axial shaft on which the impeller is arranged, the axial shaft passing through the proximal radial support and the distal radial support,

[0439] The surface to which the distal coupling portion is coupled comprises at least a portion of an outer surface of the distal support housing.

[0440] 92) The apparatus of 91) wherein the distal end of the frame is coupled to another portion of the outer surface of the distal support housing.

[0441] 93) The apparatus according to 91) wherein the left ventricular assist device further comprises a distal end element, and wherein the distal end element is coupled to another portion of the outer surface of the distal support housing.

[0442] 94) The apparatus of 91) wherein the proximal end of the frame is coupled to an outer surface of the proximal support housing.

[0443] 95) The apparatus according to 94), wherein the frame includes a plurality of strut joints at the proximal end of the frame, the strut joints being configured to remain in an open state during assembly of the left ventricular assist device to facilitate insertion of the impeller into the frame, and wherein the proximal end of the frame is coupled to the outer surface of the proximal support housing via a fixing element that maintains the strut joints in a closed state around the outer surface of the proximal support housing.

[0444] 96) The apparatus of 91) wherein the proximal radial support and the distal radial support are made of a ceramic material, and the proximal support housing and the distal support housing are made of a second material that can be molded into a desired shape.

[0445] 97) The device according to 96), wherein the proximal support shell and the distal support shell are made of metal and / or alloy.

[0446] 98) The apparatus of 97) wherein the axial shaft comprises a metal and / or alloy, and wherein the axial shaft is covered with a ceramic sleeve in an area along the axial shaft that contacts either the proximal support or the distal support during operation of the left ventricular assist device.

[0447] 99) A device comprising:

[0448] A ventricular assist device, comprising:

[0449] a frame comprising struts defining a plurality of cells, the frame being configured such that in a non-radially constrained configuration of the frame, the frame includes a generally cylindrical central portion;

[0450] a pump outlet tube defining one or more blood outlet openings, a portion of the pump outlet tube disposed outside the frame and coupled to the generally cylindrical central portion of the frame such that the portion of the pump outlet tube conforms to the strut structure of the frame;

[0451] an inner liner coupled to an inner side of the generally cylindrical central portion of the frame to provide a smooth inner surface for the generally cylindrical portion of the frame;

[0452] an impeller at least partially disposed within the generally cylindrical central portion of the frame and configured to pump blood through the tube and out of the one or more blood outlet openings; and

[0453] a protective braid disposed over a distal portion of the frame and configured to prevent structures from the left ventricle of the subject from entering the frame,

[0454] The proximal end of the protective braid is embedded between the pump outlet tube and the liner so that during crimping of the frame, the braid crimps with the pump outlet tube and the liner, thereby preventing movement of the braid relative to the pump outlet tube or the liner.

[0455] 100) The device according to 99), wherein the braid is woven into the struts of the distal portion of the frame.

[0456] 101) The device according to 99) or 100), wherein the distal portion of the frame is tapered and the protective braid extends to the end of the distal tapered portion of the frame.

[0457] 102) The device of 101), wherein the braid is covered along a distal portion of the distal tapered portion of the frame to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame.

[0458] 103) The device according to 101), wherein the braid is opened to define large holes within the distal portion of the distal tapered portion of the frame to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame.

[0459] 104) The device according to 101), wherein the braid is cut to define large holes within the distal portion of the distal tapered portion of the frame to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame.

[0460] 105) The device of 101), wherein the braid is covered along a distal portion of the distal tapered portion of the frame, and the covered braid is cut to define one or more large holes to prevent thrombus formation on the braid within the distal portion of the distal tapered portion of the frame.

[0461] 106) The apparatus of 105) wherein holes are cut from the covered braid around the entire circumference of the frame such that the covered braid defines holes extending around the entire circumference of the distal portion of the distal tapered portion of the frame.

[0462] 107) The apparatus of 106) wherein the hole is cut so that the hole extends to the distal end of the distal tapered portion of the frame so that there is a single hole extending around the entire circumference of the frame and extending to the distal end of the distal tapered portion of the frame.

Claims

1. A device for ventricular assist, comprising: A ventricular assist device, comprising: a frame comprising struts defining a plurality of cells, the frame being configured such that in a non-radially constrained configuration of the frame, the frame includes a generally cylindrical central portion; a pump outlet tube defining one or more blood outlet openings, a portion of the pump outlet tube disposed outside the frame and coupled to the generally cylindrical central portion of the frame such that the portion of the pump outlet tube conforms to the strut structure of the frame; an inner liner coupled to an inner side of the generally cylindrical central portion of the frame to provide a smooth inner surface for the generally cylindrical central portion of the frame; an impeller at least partially disposed within the generally cylindrical central portion of the frame and configured to pump blood through the pump outlet tube and out of the one or more blood outlet openings; and a protective braid disposed over a distal portion of the frame and configured to prevent structures from the left ventricle of the subject from entering the frame, The proximal end of the protective braid is embedded between the pump outlet tube and the liner so that during crimping of the frame, the protective braid crimps with the pump outlet tube and the liner, thereby preventing the protective braid from moving relative to the pump outlet tube or the liner.

2. The device according to claim 1, wherein The protective braid is woven into the struts of the distal portion of the frame.

3. The apparatus according to claim 1 or claim 2, wherein: The distal portion of the frame is tapered, and the protective braid extends to an end of the tapered distal portion of the frame.

4. The device according to claim 3, wherein The protective braid is covered along a distal portion of the tapered distal portion of the frame to prevent thrombus formation on the protective braid within the distal portion of the tapered distal portion of the frame.

5. The apparatus according to claim 3, wherein The protective braid is opened to define large pores within a distal portion of the tapered distal portion of the frame to prevent thrombus formation on the protective braid within the distal portion of the tapered distal portion of the frame.

6. The apparatus according to claim 3, wherein The protective braid is cut to define large holes within a distal portion of the tapered distal portion of the frame to prevent thrombus formation on the protective braid within the distal portion of the tapered distal portion of the frame.

7. The apparatus according to claim 3, wherein The protective braid is covered along a distal portion of the tapered distal portion of the frame, and the covered protective braid is cut to define one or more large holes to prevent thrombus formation on the protective braid within the distal portion of the tapered distal portion of the frame.

8. The apparatus according to claim 7, wherein Holes are cut from the covered protective braid around the entire circumference of the frame such that the covered protective braid defines holes extending around the entire circumference of the distal portion of the tapered distal portion of the frame.

9. The apparatus according to claim 8, wherein The hole is cut such that it extends to the distal end of the tapered distal portion of the frame so that there is a single hole extending around the entire circumference of the frame and to the distal end of the tapered distal portion of the frame.

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