Ventricular assist device

Abstract

This application relates to ventricular assist devices. Apparatus and methods are described that include an impeller (50) that includes a proximal hub (64) and a distal hub (58). Two or more helical elongate elements (52) extend from the proximal hub (64) to the distal hub (58), and an axial structure (54) is disposed inside the two or more helical elongate elements (52) and along an axis about which the helical elongate elements (52) are wrapped. The impeller (50) includes an impeller overexpansion prevention element (72). The impeller overexpansion prevention element is a single integrated structure that includes a ring (73) disposed about the axial structure (54), and a plurality of elongate elements (67), each elongate element (67) extending from the ring to a respective helical elongate element (52) and coupled to the respective helical elongate element (52) to prevent radial expansion of the impeller (50). Other applications are also described.

Description

[0001] This application is a divisional application of the application filed on April 6, 2021, with application number 202180006817.8 and invention title "Ventricular Assist Device".

[0002] Cross-reference to related applications

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

[0004] Tuval filed U.S. Provisional Patent Application No. 63 / 006,122 on April 7, 2020, entitled “Ventricular assist device”.

[0005] Tuval's U.S. Provisional Patent Application No. 63 / 114,136, entitled "Ventricular assist device," filed November 16, 2020; and

[0006] Tuval filed U.S. Provisional Patent Application No. 63 / 129,983 on December 23, 2020, entitled “Ventricular assist device”.

[0007] Each of the U.S. provisional applications cited above is incorporated herein by reference.

[0008] Field of the embodiments of the present invention

[0009] Some applications of this invention generally relate to medical devices. Specifically, some applications of this invention relate to ventricular assist devices and methods of using them. background

[0010] Ventricular assist devices are mechanical circulatory support devices 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 cardiac function deterioration during percutaneous coronary intervention. Most commonly, left ventricular assist devices are used in defective hearts to assist left ventricular function. In some cases, right ventricular assist devices are used to assist right ventricular function. These assist devices are either designed for permanent implantation or are mounted on a catheter for temporary placement.

[0011] Overview of the Implementation Examples

[0012] According to some applications of the invention, a blood pump includes an impeller. The impeller includes a proximal bushing and a distal bushing, and two or more helical elongated elements (and typically three helical elongated elements) extending from the proximal bushing to the distal bushing. An axial structure (e.g., a cylindrical axial structure, such as a spring) is disposed inside two or more helical elongated elements and arranged along the axis of the helical elongated elements about which they are wound. A membrane of material is supported between the helical elongated elements and the axial structure, such that each of the helical elongated elements with a membrane of material coupled thereto defines a corresponding blade of the impeller. An element preventing impeller over-expansion is disposed within the impeller. This element is a single integrated structure comprising a ring disposed around the axial structure and a plurality of elongated elements. Each elongated element extends from the ring to a corresponding helical elongated element and is coupled to that element to prevent radial expansion of the impeller. Typically, the elongated elements are configured not to resist compression, and are configured to prevent radial expansion of the impeller by applying tension to the helical elongated elements.

[0013] For some applications, along at least a portion of the impeller's length, as the film of the material transitions from one impeller blade to an adjacent blade, the film forms a continuous U-shaped surface, wherein the U-shaped curvature of the film is substantially uninterrupted at the axial structure. For some applications, when viewed from the distal end of the impeller, the pressure side of each blade (i.e., the side configured to push blood during impeller operation) is convex in the distal region of the impeller and concave in the proximal region. Typically, the pressure side of each blade of the impeller transitions to a substantially radial orientation within the region of the elongated element within the impeller blade.

[0014] For some applications, the impeller is manufactured by the following steps: forming a structure having a first bushing and a second bushing at its proximal and distal ends, the first and second bushings being connected to each other by at least one elongated element. The structure is at least partially axially compressed to radially expand the at least one elongated element and form at least one helical elongated element. The at least one helical elongated element is coated with a bonding agent configured to enhance the bond between the helical elongated element and the elastomeric layer. The coated helical elongated element is then coated with the elastomeric layer. Subsequently, an elastomeric membrane is attached to the at least one helical elongated element such that the at least one helical elongated element with the attached elastomeric membrane defines the blades of the impeller. For example, the helical elongated element may be immersed in an elastomeric material, and the elastomeric layer may be made of the elastomeric material. For some applications, the elastomeric membrane comprises an elastic material having a limiting elongation greater than 300%, a melt flow index of at least 4, and / or a limiting tensile strength greater than 6000 psi.

[0015] In some applications, the impeller is driven to rotate by one or more drive magnets (connected to a motor) that drive one or more driven magnets to rotate, and the driven magnets are connected to the impeller via drive cables. According to some applications of the invention, the magnetic phase difference between one or more driven magnets and one or more drive magnets is measured, and physiological parameters of a subject are determined at least in part in response to the measured magnetic phase difference. For example, based at least in part on changes in the phase difference, a computer processor can determine the difference between the subject's left ventricular pressure and the subject's aortic pressure, the subject's left ventricular pressure, events in the subject's cardiac cycle, the subject's cardiac afterload, and / or different physiological parameters. In some applications, the physiological parameters are determined by combining the phase difference measurement with one or more additional measurements (e.g., magnetic flux amplitude measurements, power consumed by the motor, and / or current consumed by the motor). Typically, such measurements are combined in a mathematical model, such as a linear regression model, and / or a spatial state model.

[0016] In some applications of the present invention, during operation as a ventricular assist device used as a blood pump, the subject's arterial pulsation is measured, and parameters are derived from the subject's arterial pulsation. Typically, as the impeller rotational speed increases, the flow rate generated by the blood pump increases. Typically, the flow generated by the blood pump is non-pulsatile because the blood pump is a continuous flow blood pump rather than a pulsatile one. Therefore, typically, as the impeller rotational speed increases and the flow rate generated by the blood pump increases, the subject's arterial pulsation decreases. In some applications, the subject's arterial pulsation is measured as the impeller rotational speed changes. Based on the above measurements, the relationship between arterial pulsation and impeller rotational speed and / or pump flow rate is derived. In some applications, based on the above relationship, the subject's natural cardiac output is derived. In some such applications, when the subject's arterial pulsation reaches zero, the relationship between the subject's arterial pulsation and pump flow rate is extrapolated to determine what the pump flow rate would be. It is assumed that at this value, the blood pump is displacing the heart's inherent function, and the flow rate generated by the pump at this value provides an approximation of the subject's natural cardiac output.

[0017] Therefore, according to some applications of the present invention, an apparatus is provided, the apparatus comprising:

[0018] A blood pump, configured to be placed inside the subject's body, includes:

[0019] Impeller, the impeller includes:

[0020] Proximal bushing and distal bushing;

[0021] Two or more helical elongated elements, extending from the proximal bushing to the distal bushing;

[0022] An axial structure, wherein the axial structure is disposed inside two or more helical elongated elements and is arranged along the axis around which the helical elongated elements are wound; and

[0023] A membrane of material, the membrane of which is supported between a helical elongated element and an axial structure, such that each blade of the helical elongated element, with the membrane of material connected thereto, defines a corresponding impeller; and

[0024] The impeller over-extension prevention element is a single integrated structure comprising a ring and multiple elongated elements, the ring being arranged around the axial structure.

[0025] Each elongated element extends from the ring to the corresponding helical elongated element and is connected to the corresponding helical elongated element to prevent radial expansion of the impeller.

[0026] In some applications, the impeller includes three helical elongated elements such that the three helical elongated elements with a membrane of material connected thereto define three blades of the impeller, and a corresponding elongated element extends from the ring to each of the three helical elongated elements such that a corresponding elongated element exists in each of the three blades of the impeller.

[0027] In some applications, the elongated element is configured not to resist compression, and the elongated element is configured to prevent the impeller from radially expanding by applying tension to the helical elongated element.

[0028] In some applications, along at least a portion of the impeller's length, as the film of the material transitions from one impeller blade to an adjacent blade, the film forms a continuous U-shaped surface, wherein the U-shaped curvature of the film is substantially uninterrupted at the axial structure.

[0029] In some applications, when viewed from the distal end of the impeller, the pressure side of each blade (configured to push blood during impeller operation) is convex in the distal region of the impeller and concave in the proximal region. In some applications, the pressure side of each blade transforms into a substantially radial orientation within the region of the elongated element within the impeller blade.

[0030] In some applications, the helical elongated element is coated with a binder configured to enhance the bond between the helical elongated element and the film of the material. In some applications, the film of the material comprises an elastomeric material, and the binder comprises at least two functional groups configured to bond with the helical elongated element and the elastomeric material, respectively. In some applications, the binder comprises a silane compound.

[0031] In some applications, the device also includes a layer of elastomer disposed between the film of the material and the binder. In some applications, the layer of elastomer is configured to round off the helical elongated element. In some applications, the film of the material is made of an elastomer. In some applications, the elastomer comprises polycarbonate-based thermoplastic polyurethane.

[0032] In some applications, the axial structure includes a spring. In some applications, the spring includes a tube located at a midpoint along the length of the spring, and a ring is arranged around the tube.

[0033] Therefore, according to some applications of the present invention, a method is provided, the method comprising:

[0034] The impeller is manufactured using the following steps:

[0035] A structure is formed having a first bushing and a second bushing at its proximal and distal ends, the first bushing and the second bushing being connected to each other by at least one elongated element.

[0036] The structure is at least partially compressed axially, causing the at least one elongated element to expand radially and form at least one helical elongated element;

[0037] At least one helical elongated element is coated with a binder, the binder being configured to enhance the bond between the helical elongated element and the elastomer layer;

[0038] The spiral-shaped elongated element is coated with an elastomer layer; and

[0039] Subsequently, the elastomeric membrane is attached to at least one helical elongated element such that the at least one helical elongated element with the elastomeric membrane attached thereto defines the blades of the impeller.

[0040] In some applications, attaching an elastomeric membrane to at least one helical elongated element such that the at least one helical elongated element with the elastomeric membrane attached thereto defines the blades of an impeller includes immersing the helical elongated element in an elastomeric material, the elastomeric membrane being made of the elastomeric material.

[0041] In some applications, the elastomeric membrane comprises an elastic material having an ultimate elongation of more than 300%. In some applications, the elastomeric membrane comprises an elastic material having a melt flow index of at least 4. In some applications, the elastomeric membrane comprises an elastic material having an ultimate tensile strength greater than 6000 psi.

[0042] In some applications, coating at least one helical elongated element with a binder includes coating at least one helical elongated element with a silane compound containing a first functional group and a second functional group, the first functional group being configured to bond with the helical elongated element and the second functional group being configured to bond with the elastomer layer.

[0043] In some applications, the elastomeric layer is made of a given elastomeric material, and the elastomeric membrane is made of a given elastomeric material. In some applications, the elastomeric layer is made of a first elastomeric material, and the elastomeric membrane is made of a second elastomeric material different from the first elastomeric material.

[0044] In some applications, coating a spiral elongated element with an elastomeric layer involves spraying an elastomeric layer onto the spiral elongated element. In some applications, coating a spiral elongated element with the elastomeric layer involves at least partially rounding the coated spiral elongated element.

[0045] In some applications, coating a spiral elongated element with an elastomeric layer includes coating the coated spiral elongated element with an elastomeric layer within a given time period during which at least one spiral elongated element is coated with a binder. In some applications, coating a coated spiral elongated element with an elastomeric layer further includes spraying additional elastomeric material onto the coated spiral elongated element after coating the coated spiral elongated element with an elastomeric layer within a given time period during which at least one spiral elongated element is coated with a binder.

[0046] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0047] Ventricular assist device, the ventricular assist device comprising:

[0048] An impeller, configured to be placed in the left ventricle of the subject;

[0049] motor;

[0050] At least one drive magnet is coupled to a motor and configured to be rotated by the motor;

[0051] At least one driven magnet, which is magnetically coupled to a driving magnet and configured to be rotated by the driven magnet;

[0052] A drive cable extends from the driven magnet and is configured to transmit rotational motion from the driven magnet to the impeller;

[0053] A set of sensors configured to detect the magnetic phase difference between the driven magnet and the driving magnet; and

[0054] A computer processor configured to receive a detected magnetic phase difference and, at least in part, in response to the detected magnetic phase difference, determine physiological parameters of a subject.

[0055] In some applications, the set of sensors is also configured to measure magnetic flux amplitude signals, and the computer processor is configured to determine the subject's physiological parameters based at least in part on a combination of the magnetic flux amplitude signals and the detected magnetic phase difference.

[0056] In some applications, the computer processor is configured to determine the pressure difference between the subject's left ventricle and the subject's aorta, at least in part in response to the magnetic phase difference between the driven and driven magnets. In some applications, the computer processor is configured to determine the subject's left ventricular pressure, at least in part in response to the magnetic phase difference between the driven and driven magnets. In some applications, the computer processor is configured to determine events in the subject's cardiac cycle, at least in part in response to the magnetic phase difference between the driven and driven magnets.

[0057] In some applications, this set of sensors includes a first magnetometer and a second magnetometer, the first magnetometer being configured to measure the magnetic phase of a driven magnet and the second magnetometer being configured to measure the magnetic phase of a driving magnet. In some applications, the second magnetometer is configured to measure the magnetic phase of the driving magnet by measuring the magnetic phase of the motor.

[0058] In some applications, the computer processor is configured to receive a signal indicating the current consumption of a motor and is configured to determine the subject's physiological parameters based at least in part on a combination of the motor's current consumption and a detected magnetic phase difference. In some applications, the set of sensors is also configured to measure a magnetic flux amplitude signal, and the computer processor is configured to determine the subject's physiological parameters based at least in part on a combination of the motor's current consumption, the magnetic flux amplitude signal, and the detected magnetic phase difference.

[0059] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0060] A ventricular assist device, comprising an impeller configured to be placed in the left ventricle of a subject and configured to pump blood from the subject's left ventricle to the subject's aorta;

[0061] A blood pressure sensor configured to measure the aortic pressure of a subject;

[0062] The computer processor is configured as follows:

[0063] The subject's arterial pulsation was derived from the measured aortic pressure; and

[0064] The subject's natural cardiac output was estimated, at least in part, based on arterial pulsation.

[0065] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0066] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0067] impeller;

[0068] The frame, which is arranged around the impeller,

[0069] A rigid axial shaft extends from the proximal end of the frame to the distal end of the frame. An impeller is coupled to the rigid axial shaft, which includes a proximal portion and a distal portion connected to each other via a joint. The proximal and distal portions are configured to bend relative to each other via the joint.

[0070] For some applications, the frame has a length exceeding 25 mm.

[0071] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0072] Impeller, the impeller comprising:

[0073] Proximal bushing and distal bushing;

[0074] Multiple spiral-shaped elongated components;

[0075] An axial structure, disposed inside the helical elongated element and along the axis around which the helical elongated element is wound; and

[0076] A membrane of elastomeric material is supported between a helical elongated element and an axial structure, such that each helical elongated element with the elastomeric material membrane coupled thereto defines a corresponding blade of the impeller.

[0077] Along at least a portion of the impeller's length, as the membrane of the elastomeric material transitions from one impeller blade to an adjacent blade, the elastomeric membrane forms a continuous U-shaped curvature, wherein the U-shaped curvature of the elastomeric material membrane is substantially uninterrupted at the axial structure.

[0078] In some applications, the axial structure includes a cylindrical axial structure. In some applications, the cylindrical axial structure includes a spring.

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

[0080] A ventricular assist device is inserted through an arterial incision and into the subject's vascular system via an inlet sheath. The ventricular assist device includes a delivery catheter, a drive cable, and an outer tube surrounding the drive cable.

[0081] Remove the delivery device sheath while the ventricular assist device is still within the subject's vascular system; and

[0082] A sterile sleeve is used between the outer tube and the delivery catheter to maintain the sterility of the arterial incision while allowing the outer tube to move relative to the delivery catheter.

[0083] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0084] The blood pump includes:

[0085] Axial shaft;

[0086] An impeller is mounted on an axial shaft;

[0087] A motor unit, comprising a motor configured to drive an impeller by rotating it in a given direction of rotation to pump blood from the distal end of the impeller to the proximal end of the impeller.

[0088] A drive cable, configured to extend from the motor unit to an axial shaft, is configured to transmit rotational motion from the motor to the impeller via rotation.

[0089] At least a portion of the drive cable comprises two or more layers, each layer comprising multiple wires.

[0090] In two or more layers, the multiple wires of each layer are arranged in a coiled configuration, such that in response to rotation of the drive cable in a given rotational direction, the wires of each layer are at least partially unwound, causing that portion of the drive cable to shorten axially.

[0091] The drive cable is kept in a pre-tensioned state so that even when the impeller is stationary, the drive cable is stretched relative to its stationary state.

[0092] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0093] The blood pump includes:

[0094] Axial shaft;

[0095] An impeller is mounted on an axial shaft;

[0096] A motor unit including a motor configured to drive an impeller to pump blood from the distal end of the impeller to the proximal end of the impeller by rotating the impeller counterclockwise when viewed from the proximal end to the distal end of the impeller.

[0097] A drive cable, configured to extend from the motor unit to an axial shaft, is configured to transmit rotational motion from the motor to the impeller via rotation.

[0098] At least a portion of the drive cable comprises two or more layers, each layer comprising multiple wires.

[0099] Multiple lines in each of two or more layers are configured as a left-hand coiled configuration.

[0100] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0101] The blood pump includes:

[0102] Axial shaft;

[0103] An impeller is mounted on an axial shaft;

[0104] A motor unit including a motor configured to drive an impeller to pump blood from the distal end of the impeller to the proximal end of the impeller by rotating the impeller in a clockwise direction when viewed from the proximal end to the distal end of the impeller.

[0105] A drive cable, configured to extend from the motor unit to an axial shaft, is configured to transmit rotational motion from the motor to the impeller via rotation.

[0106] At least a portion of the drive cable comprises two or more layers, each layer comprising multiple wires.

[0107] In two or more layers, the multiple lines in each layer are configured as a right-hand coiled configuration.

[0108] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0109] The blood pump includes:

[0110] Axial shaft;

[0111] An impeller is mounted on an axial shaft;

[0112] A motor unit comprising a motor configured to drive an impeller to pump blood from a distal end of the impeller to a proximal end of the impeller by rotating the impeller in a given direction of rotation.

[0113] A drive cable, configured to extend from the motor unit to an axial shaft, is configured to transmit rotational motion from the motor to the impeller via rotation.

[0114] At least a portion of the drive cable includes inner and outer layers coaxial with each other, and each layer includes multiple wires arranged in a coiled configuration.

[0115] The ratio of the number of lines in the outer layer to the number of lines in the inner layer is between 2:3 and 2:5, and the ratio of the diameter of the lines in the outer layer to the diameter of the lines in the inner layer is between 3:2 and 5:2.

[0116] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0117] The blood pump includes:

[0118] Axial shaft;

[0119] An impeller is mounted on an axial shaft;

[0120] A motor unit comprising a motor configured to drive an impeller to pump blood from a distal end of the impeller to a proximal end of the impeller by rotating the impeller in a given direction of rotation.

[0121] A drive cable configured to extend from the motor unit to an axial shaft, the drive cable being configured to transmit rotational motion from the motor to the impeller via rotation; and

[0122] A drive cable support tube, wherein the drive cable is configured to rotate within the drive cable support tube, and at least a portion thereof comprises:

[0123] The inner and outer layers comprise corresponding materials that differ from each other; and

[0124] The coiled wire embedded between the inner and outer layers is configured to maintain the substantially circular cross-section of the drive cable support tube even in areas where the drive cable support tube undergoes substantial bending.

[0125] Generally, in the specification and claims of this application, when the terms "proximal" and related terms are used with respect to a device or a portion thereof, the terms "proximal" and related terms should be interpreted as meaning 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 point through which the device is inserted into the body of the subject. When the terms "distal" and related terms are used with respect to a device or a portion thereof, the terms "distal" and related terms should be interpreted as meaning 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 from the point through which the device is inserted into the body of the subject.

[0126] The scope of this invention includes the use of the devices and methods described herein in anatomical locations other than the left ventricle and aorta. Therefore, ventricular assist devices and / or portions thereof are sometimes referred to herein (in the specification and claims) as blood pumps.

[0127] The invention will be more fully understood from the following detailed description of embodiments thereof, taken in conjunction with the accompanying drawings, in which: Attached Figure Description

[0128] Figure 1A , Figure 1B , Figure 1C and Figure 1D This is a schematic diagram of a ventricular assist device according to some applications of the present invention, wherein the distal end of the ventricular assist device is configured to be placed in the left ventricle of a subject;

[0129] Figure 1E and Figure 1F This is a schematic diagram of a ventricular assist device according to some applications of the present invention, which includes a braided structure and / or mesh in the distal region, the braided structure and / or mesh being configured to separate the blood inlet opening of the ventricular assist device from the internal structure of the ventricle;

[0130] Figure 2 This is a schematic diagram of a frame housing an impeller for a ventricular assist device according to some applications of the present invention;

[0131] Figure 3A , Figure 3B , Figure 3C , Figure 3D , Figure 3E and Figure 3F This is a schematic diagram of the impeller or a portion thereof of a ventricular assist device according to some applications of the present invention;

[0132] Figure 3 Gi and Figure 3 Gii These are pictures of the impellers of ventricular assist devices according to some applications of the present invention;

[0133] Figure 4 This is a schematic diagram of an impeller disposed inside the frame of a ventricular assist device according to some applications of the present invention;

[0134] Figure 5A and Figure 5B This is a schematic diagram of the impeller and frame of a ventricular assist device in a non-radial constraint state and a radial constraint state, respectively, according to some applications of the present invention;

[0135] Figure 6A and Figure 6BThis is a schematic diagram of a ventricular assist device according to some applications of the present invention, showing the impeller of the ventricular assist device at various stages of its motion cycle relative to the frame of the ventricular assist device.

[0136] Figure 6C This is a schematic diagram of a distal end element of a ventricular assist device according to some applications of the present invention, the distal end element including an axial shaft receiving tube and a distal end portion;

[0137] Figure 6D and 6E This is a schematic diagram of a connecting element for coupling to an impeller bushing according to some applications of the present invention, the connecting element extending proximally and serving as a stop;

[0138] Figure 7A This is a schematic diagram of the motor unit of a ventricular assist device according to some applications of the present invention;

[0139] Figure 7Bi and Figure 7 Bii This is a schematic diagram of the motor unit of a ventricular assist device according to some applications of the present invention;

[0140] Figure 8A It is a graph showing how the length of the drive cable of the ventricular assist device, as measured in the experiment, changes with the pressure gradient countered by the blood pump impeller;

[0141] Figure 8B and Figure 8C It is a graph showing how the results of magnetic phase measurements performed on the blood pump change with the pressure gradient countered by the impeller of the blood pump, as measured in the experiment.

[0142] Figure 9A , Figure 9B , Figure 9C , Figure 9D , Figure 9E , Figure 9F and Figure 9G This is a schematic diagram of a motor unit support configured to support a motor unit on a patient's leg, according to some applications of the present invention.

[0143] Figure 10A , Figure 10B and Figure 10C This is a schematic diagram of the drive cable of a ventricular assist device according to some applications of the present invention;

[0144] Figure 10D This is a schematic diagram of a drive cable support tube according to some applications of the present invention;

[0145] Figure 11A , Figure 11B , Figure 11C , Figure 11D and Figure 11E This is a schematic diagram of an apparatus and method for cleaning drive cables, radial supports, and / or impeller bushings of a ventricular assist device according to some applications of the present invention;

[0146] Figure 12A and Figure 12B This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including an inner liner located on the inside of a frame housing an impeller;

[0147] Figure 13 This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device having a frame that houses an impeller, the frame defining a cylindrical portion, at least the distal portion of which is not covered;

[0148] Figure 14 This is a schematic diagram of a ventricular assist device placed in the left ventricle of a subject according to some applications of the present invention, wherein a cross-sectional view of the left ventricle is shown;

[0149] Figure 15A , Figure 15B , Figure 15C and Figure 15D This is a schematic diagram of a distal end element of a ventricular assist device according to some applications of the present invention, which is at least partially bent to define a question mark shape or a tennis racket shape;

[0150] Figure 16A and Figure 16B This is according to some applications of the present invention. Figure 15D A schematic diagram of a ventricular assist device, which is placed in the left ventricle of a subject;

[0151] Figure 17Ai and Figure 17Aii This is a schematic diagram of a ventricular assist device according to some applications of the present invention, which has a balloon disposed on its distal end portion, the balloon being configured to facilitate movement of an axial shaft relative to the wall of the ventricle;

[0152] Figure 17Bi and Figure 17 Bii This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device having a connector configured to facilitate pivoting of a distal end portion of the ventricular assist device relative to an axial shaft of the ventricular assist device;

[0153] Figure 17C This is a schematic diagram of a ventricular assist device according to some applications of the present invention. The outer tube of the ventricular assist device is shaped with a predetermined curvature such that when the axial shaft is placed in the left ventricle of the subject, the axial shaft of the ventricular assist device remains in a substantially straight configuration.

[0154] Figure 17D This is a schematic diagram of a ventricular assist device, which has a distal end of tissue configured to be anchored to the apex of the left ventricle;

[0155] Figure 18A , Figure 18B and Figure 18C This is a schematic diagram of the distal radial support member of a ventricular assist device according to a corresponding application of the present invention;

[0156] Figure 19A , Figure 19B , Figure 19C , Figure 19D and Figure 19E This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including a pump outlet tube configured to bend when blood is pumped through the pump outlet tube, the pump outlet tube being rotatable relative to a distal end portion of the ventricular assist device;

[0157] Figure 19F This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including a bending element made of shape memory material and configured to provide a predetermined curvature to a portion of the ventricular assist device, the bending element being rotatable relative to a distal end portion of the ventricular assist device;

[0158] Figure 20A , Figure 20B and Figure 20C This is a schematic diagram of a ventricular assist device according to some applications of the present invention, wherein the axial shaft of the ventricular assist device includes a joint, such as a universal joint;

[0159] Figure 21 This is a schematic diagram of a ventricular assist device including one or more blood pressure measuring tubes according to some applications of the present invention;

[0160] Figure 22A and Figure 22B This is a schematic diagram of a sterile sleeve according to some applications of the present invention, the sterile sleeve being configured to form a seal between a delivery catheter and the outer tube of a ventricular assist device;

[0161] Figure 23A , Figure 23B and Figure 23C This is a schematic diagram of a distal straightener according to some applications of the present invention, the distal straightener being used to straighten the distal end when the guide wire is inserted into the distal end of a ventricular assist device; and

[0162] Figure 24A , Figure 24B and Figure 24CThis is a graph showing the results of measurements performed during the use of a left ventricular assist device in some applications according to the present invention.

[0163] Detailed description of the embodiments

[0164] Now for reference Figure 1A , Figure 1B and Figure 1C These figures are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, wherein the distal end of the ventricular assist device is configured to be disposed in the left ventricle 22 of the subject. Figure 1A An overview of a ventricular assist device system including a control console 21 and a motor unit 23 is shown. (As described below, the motor unit is typically a handle that houses the motor.) Figure 1B A ventricular assist device inserted into the left ventricle of a subject is shown, and Figure 1C The pump 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 aortic valve 26 of the subject, such that a proximal end 28 of the pump outlet tube is positioned within the subject's aorta 30, and a distal end 32 of the pump outlet tube is positioned within the left ventricle 22. The pump outlet tube 24 is typically an elongated tube, and typically, its axial length is substantially greater than its diameter. The scope of the invention includes the use of the devices and methods described herein in anatomical locations other than the left ventricle and aorta. Therefore, the ventricular assist device and / or portions thereof are sometimes referred to herein (in the specification and claims) as a blood pump.

[0165] In some applications, ventricular assist devices (VADs) are used to assist left ventricular function in a subject during percutaneous coronary intervention (PCI). In this case, VADs are typically used for a period of up to 10 hours (e.g., up to 6 hours), during which there is a risk of hemodynamic instability (e.g., during or immediately after PCI). Alternatively or additionally, VADs are used to assist left ventricular function in patients with cardiogenic shock for a longer period (e.g., 2-20 days, or 4-14 days), which can include any low cardiac output state (e.g., acute myocardial infarction, myocarditis, cardiomyopathy, postpartum, etc.). In some applications, VADs are used to assist left ventricular function in a subject for even longer periods (e.g., weeks or months), for example, in bridge-to-recovery therapy. In some of these applications, the ventricular assist device is permanently or semi-permanently implanted, and the impeller of the ventricular assist device is percutaneously powered, for example, by using an external antenna magnetically coupled to the impeller.

[0166] like Figure 1B As shown, Figure 1B The steps for deploying a ventricular assist device in the left ventricle are illustrated. Typically, the distal end of the ventricular assist device is guided into the left ventricle via a guide wire 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 guide wire is withdrawn from the subject's body. Typically, the retraction of the delivery catheter causes the self-expanding portion 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. For some applications, in order to withdraw the left ventricular device from the subject's body at the end of treatment, the delivery catheter is advanced over the distal end of the device, causing the self-expanding portion 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, causing the self-expanding portion of the distal end of the device to assume a radially constrained configuration.

[0167] 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 ventricle of the subject under ultrasound guidance.

[0168] Now for reference Figure 1C The diagram shows the pump portion 27 of the ventricular assist device 20 in more detail. Typically, an impeller 50 is disposed within the distal segment 102 of the pump outlet tube 24 and 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 its distal end 32, through which blood flows from the left ventricle into the pump outlet tube during impeller operation. For some applications, the proximal segment 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.

[0169] For some applications, this typically includes the console 21 of the computer processor 25 (such as...). Figure 1A (As shown) controls the rotation of the impeller. For example, a computer processor can control motor 74 (e.g., as shown) Figure 7A As shown), motor 74 is installed in motor unit 23 ( Figure 1A (shown) and the motor 74 is connected via drive cable 130 (e.g., in) Figure 7A(Shown) The impeller is driven 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, as described in further detail below. Typically, the operations performed by the computer processor described herein convert the physical state of the memory, which is a real physical artifact communicating with the computer processor, into different magnetic polarities, charges, etc., depending on the memory technology used. The computer processor 25 is typically a hardware device programmed with computer program instructions to produce a dedicated computer. For example, when programmed to perform the techniques described herein, the computer processor 25 typically acts as a dedicated ventricular assist computer processor and / or a dedicated blood pump computer processor.

[0170] For some applications, cleaning system 29 (in) Figure 1A As shown in the diagram, a driving fluid (e.g., a glucose solution) passes through multiple parts of the ventricular assist device 20, for example, to cool multiple parts of the device and / or to flush debris from multiple parts of the device. The cleaning system 29 will be described in further detail below.

[0171] Typically, a frame 34 is disposed within the pump outlet tube 24, surrounding the impeller 50, along the distal segment 102 of the pump outlet tube 24. 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 such that at least a portion of the frame (and therefore the distal segment 102 of the tube 24) presents a generally circular, elliptical, or polygonal cross-sectional shape when no force is applied to the distal segment 102 of the tube 24. By presenting its generally circular, elliptical, or polygonal cross-sectional shape, the frame is configured to hold 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 subject's body such that the distal portion of the pump outlet tube is at least partially located within the left ventricle.

[0172] For some applications, along the proximal segment 106 of the pump outlet tube 24, the frame is not disposed within the pump outlet tube, so the pump outlet tube is not supported by the frame 34 in the open position. The pump outlet tube 24 is typically made of a collapsible material that is impermeable to blood. For example, the pump outlet tube 24 may comprise polyurethane, polyester, and / or silicone. Alternatively or additionally, the pump outlet tube may be made of polyethylene terephthalate (PET) and / or polyether block amide (e.g., PEBAX®). For some applications (not shown), the pump outlet tube is reinforced with a reinforcing structure (e.g., a braided reinforcement such as braided nitinol tubing). 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 aortic valve of the subject, entering the ascending aorta from the left ventricle of the subject, such as... Figure 1B As shown.

[0173] As described above, the pump outlet tube typically defines one or more blood inlet openings 108 at its distal end, through which blood flows from the left ventricle into the pump outlet tube during impeller operation. For some applications, the proximal portion 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. Typically, the pump outlet tube defines multiple blood outlet openings 109, for example, between two and eight blood outlet openings (e.g., between two and four blood outlet openings). During impeller operation, the pressure of the blood flow through the pump outlet tube typically keeps the proximal portion of the tube open. For some applications, such as in the event of impeller failure, the proximal portion of the pump outlet tube is configured to collapse inward in response to 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 retrograde blood flow from the aorta into the left ventricle.

[0174] Refer again Figure 1C For some applications, frame 34 is shaped such that it defines a proximal conical portion 36, a central cylindrical portion 38, and a distal conical portion 40. Typically, the proximal conical portion is such that the narrow end of the cone is proximal to the wide end of the cone. More typically, the distal conical portion is such that the narrow end of the cone is distal to the wide end of the cone. For some applications, pump outlet tube 24 extends to the distal end of cylindrical portion 38 (or slightly proximal or distal thereto), such that the distal end of pump outlet tube defines a single axially oriented blood inlet opening 108, as... Figure 1C As shown. For some applications, within at least a portion of frame 34, lining 39 rests on the frame, as referenced below. Figures 12A-12BAs described above. Depending on the application, the liner partially or completely overlaps the pump outlet pipe 24 above the liner-lined portion of the frame. For such applications, the distal end of the liner defines a single axially oriented blood inlet opening 108. For some applications, both the pump outlet pipe and the liner terminate before the distal end of the cylindrical portion of the frame, leaving the distal portion of the cylindrical portion of the frame uncovered, as described below. Figure 13 As stated above.

[0175] Typically, the pump outlet tube 24 includes a tapered proximal portion 42 and a cylindrical central portion 44. (Typically, the tapered proximal portion 42 is entirely within the proximal segment 106 described above, and the cylindrical central portion typically extends from within the proximal segment 106 to the distal segment 102.) The proximal tapered portion typically makes the narrow end of the cone proximal 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 portion 42 of the tube 24. For some such applications, the blood outlet opening is teardrop-shaped, such as... Figure 1C As shown. Typically, the teardrop-shaped property of the blood outlet opening is combined with an opening that extends at least partially along the proximal conical segment of tube 24, such that blood flows out of the blood outlet opening at its location along a flow line substantially parallel to the longitudinal axis of tube 24.

[0176] For some applications (not shown), the diameter of the pump outlet pipe 24 varies along the length of its central portion, giving the central portion a truncated cone shape. For example, the central portion of the pump outlet pipe may widen from its proximal end to its distal end, or it may narrow from its proximal end to its distal end. For some applications, the central portion of the pump outlet pipe has a diameter between 5 mm and 7 mm at its proximal end, and between 8 mm and 12 mm at its distal end.

[0177] Refer again Figure 1C A typical ventricular assist device includes a distal end element 107 disposed distally relative to the frame 34 and including an axial shaft receiving tube 126 and a distal end portion 120, both of which will be described in further detail below.

[0178] Now for reference Figure 1D , Figure 1DThis is a schematic diagram of a ventricular assist device 20 according to some applications of the present invention, wherein a pump outlet tube 24 extends to the end of a distal tapered portion 40 of a frame, and the pump outlet tube defines a plurality of lateral blood inlet openings 108. For such applications, the pump outlet tube typically defines a distal tapered portion 46, wherein the narrow end of the tapered portion is distal relative to the wide end of the tapered portion. For some such applications, the pump outlet tube defines two to four lateral blood inlet openings. Typically, for such applications, the area defined by each blood inlet opening 108 is 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), for example, 20-60 square millimeters or 30-50 square millimeters. Optionally or additionally, the outlet tube may define a greater number of smaller blood inlet openings (not shown), such as more than 10, more than 50, more than 100, or more than 150, for example, 50-100, 100-150, or 150-200. For some such applications, the area defined by each smaller blood inlet opening is 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, 0.1-5 square millimeters, 0.2-0.5 square millimeters, or 0.3-1 square millimeters.

[0179] Typically, the distal tapered portion 46 of the pump outlet pipe is configured to reduce the risk of structures from the left ventricle (e.g., chordae tendineae, cardiac columns, and / or papillary muscles) entering the frame and potentially being damaged by the impeller and / or axial shaft (on which the impeller is mounted) and / or causing damage to the left ventricular assist device. Therefore, for some applications, the small blood inlet opening is shaped such that the width (or span) of the opening in at least one direction is less than 1 mm, for example, 0.1-1 mm, or 0.3-0.8 mm. By defining such a small width (or span), typically, structures from the left ventricle (e.g., chordae tendineae, cardiac columns, and / or papillary muscles) are prevented from entering the frame. For some applications, the small blood inlet opening is defined as generally rectangular (or elliptical) in shape. For some such applications, the length-to-width ratio of the small blood inlet opening is between 1.1:1 and 4:1, for example, between 3:2 and 5:2. For some applications, by having a shape in which the small blood inlet opening is configured to (a) prevent structures from the left ventricle (e.g., chordae tendineae, cardiac columns, and / or papillary muscles) from entering the frame, but (b) provide a portion of the pump outlet tube defining the small blood inlet opening, which has a relatively high porosity. Typically, the portion of the pump outlet tube defining the small blood inlet opening has a porosity greater than 40%, for example greater than 50% (where porosity is defined as the percentage of the area of ​​pores in that portion available for blood flow).

[0180] Now for reference Figure 1E and Figure 1F , Figure 1E and Figure 1F This is a schematic diagram of a ventricular assist device 20. According to some applications of the invention, the ventricular assist device includes a braided structure 260 and / or a mesh 282 in a distal region of the device, the braided structure and / or mesh being configured to separate the blood inlet opening of the ventricular assist device from the internal structure of the ventricle. The braided structure 260 is typically consistent with that in US 2019 / 0209758 concerning Tuval. Figure 20B The described weave structure 260 is substantially similar, and is incorporated herein by reference. The mesh 282 is substantially similar to that described in U.S. Publication 2019 / 0209758 concerning Tuval. Figure 21 The network 282 described in D is incorporated herein by reference.

[0181] refer to Figure 1E For some applications, the braided structure 260 (e.g., a braided metal or alloy, such as a shape memory alloy (e.g., nitinol)) is disposed in the distal region of the device. For example, the braided material may be disposed at the distal end of the device. Optionally or additionally, the device may include a distal end element 107 (typically as shown in reference 107). Figures 14-16B The braided material is disposed around a portion of the device to cover a portion of the distal end element. For some applications, the braided material is disposed over at least a portion of the frame 34. For example, the braided material may surround a portion of the frame extending distally from at least one longitudinal position along the frame (where the blood outlet tube 24 ends and / or the liner 39 ends) to the distal end of the frame. For some applications, the braided structure is configured to cover the blood inlet opening 108.

[0182] like Figure 1F As shown, for some applications, the outer surface of the distal end element 107 includes a radially expandable mesh 282 configured to self-expand when the distal end element 107 is positioned in the left ventricle of a subject. For some applications, the device includes a distal end element, which is generally as shown in the reference... Figures 14-16B The mesh is disposed around a portion of the device to cover a portion of the distal end element. For some applications, the mesh is disposed over at least a portion of the frame 34. For example, the mesh may surround a portion of the frame extending distally from at least one longitudinal position along the frame (where the blood outlet tube 24 ends and / or the liner 39 ends) to the distal end of the frame. For some applications, the mesh is configured to cover the blood inlet opening 108.

[0183] Typically, the braided structure 260 and / or mesh 282 separate one or more blood inlet openings 108 from the three-dimensional internal structure of the left ventricle. In this way, the braided structure 260 and / or mesh 282 separate one or more blood inlet openings 108 from the interventricular septum, chordae tendineae, papillary muscles, cardiac columns, and / or the apex of the left ventricle. As an alternative or supplement to the braided structure and / or mesh used to separate one or more blood inlet openings 108 from the internal structure of the left ventricle, cells of the frame 34 near the blood inlet openings 108 are configured to define openings smaller than those defined in other parts of the frame. For example, the openings defined by cells in the distal conical portion of the frame are smaller than those defined by cells in the proximal conical portion of the frame. Optionally or additionally, the openings defined by cells in the distal conical portion of the frame are smaller than those defined by cells in the columnar portion of the frame.

[0184] Now for reference Figure 2 , Figure 2 This is a schematic diagram of a frame 34 housing the impeller of a ventricular assist device 20 according to some applications of the present invention. As described above, the frame 34 is typically made of a shape memory alloy such as nitinol, and the shape memory alloy of the frame is shaped such that the frame (and therefore the tube 24) has a generally circular, elliptical, or polygonal cross-sectional shape when no force is applied to the pump outlet tube 24 and / or the frame 34. By presenting its generally circular, elliptical, or polygonal cross-sectional shape, the frame is configured to keep the distal portion of the tube in the open state.

[0185] Typically, the frame is a support frame because it comprises pillars that sequentially define the cells. More typically, the frame is covered by the pump outlet pipe 24 and / or by the liner 39, as referenced below. Figures 12A-12B As described below, for some applications, the impeller 50 reciprocates axially relative to the frame 34. Typically, during the movement of the impeller relative to the frame, the portion of the impeller defining its maximum span is positioned within the cylindrical portion 38 of the frame 34. In some cases, if the cell of the cylindrical portion 38 of the frame 34 is too large, the pump outlet pipe 24 and / or liner 39 is stretched between the edges of the cell, causing the pump outlet pipe 24 and / or liner 39 to not define a circular cross-section. For some applications, if this occurs in the area where the portion defining the impeller's maximum span is located, this results in a non-constant clearance between the edge of the impeller blades and the pipe 24 (and / or liner) at that position during the impeller's rotation cycle. For some applications, this may lead to increased hemolysis compared to a situation where there is a constant clearance between the edge of the impeller blades and the pipe 24 (and / or liner) at that position during the impeller's rotation cycle.

[0186] refer to Figure 2 At least in part, taking into account the problems described in the previous paragraph, within the columnar portion 38 of frame 34, the frame defines a large number of relatively small cells. Typically, when the frame is positioned in its non-radial constraint configuration, the maximum cell width CW (i.e., the distance, as measured around the circumference of columnar portion 38, from the inner edge of the strut at the central joint on one side of the cell to the inner edge of the strut at the central joint on the other side of the cell) of each cell within the columnar portion of the frame is less than 2 mm, for example, between 1.4 mm and 1.6 mm, or between 1.6 and 1.8 mm. Due to the relatively small size of the cells, the pump outlet pipe 24 (and / or liner) defines a substantially circular cross-section within the columnar portion of the frame.

[0187] Still referencing Figure 2 And starting from the proximal end of the frame (on the left side of the figure), the frame typically defines the following portion: (a) a connecting portion 31, through which the frame is connected to the proximal support 116 of the ventricular assist device (in Figure 4 (b) the proximal conical portion 36, (c) the cylindrical portion 38, (d) the distal conical portion 40, and (e) the distal strut joint 33 are shown. As shown, when the frame transitions from the proximal end of the frame towards the center of the frame (e.g., when the frame passes through the connecting portion 31, through the proximal conical portion 36, and transitions to the cylindrical portion 38), the struts 37 of the frame pass through joints 35, where two struts branch off from a single strut in a Y-shape. As described in further detail below, typically, the frame 34 is placed in the delivery conduit 143 in a radially constrained (i.e., coiled) configuration by being axially elongated. Furthermore, typically, the frame transmits its radial narrowing to the impeller, and the impeller becomes radially constrained by being axially elongated within the frame. For some applications, the struts of the frame configured as described above facilitate the transmission of axial elongation from the delivery conduit (or other means configured to coil the frame) to the frame, which in turn facilitates the transmission of axial elongation to the impeller. This is because the pairs of struts branching from each joint 35 are configured to pivot around the joint and move closer to each other, thus closing.

[0188] Still referencing Figure 2 For some applications, when the frame is connected to the axial shaft 92 (in Figure 4 As shown in the diagram, the distal support joint 33 is not circumferentially connected and is typically configured to remain in the open position so that the impeller is placed within the frame via the distal end of the frame. Subsequently, the distal support portion closes around the outside of the distal support 118, as described below. Figures 5A-5B Further detailed description. For some applications, the proximal end of the distal end element 107 (e.g. Figure 1C(As shown) the distal support portion is held in its closed configuration around the outside of the distal support 118.

[0189] Typically, when positioned in its non-radial constraint 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, 25-50 mm or 30-45 mm. Typically, when positioned in its radial constraint configuration (within the delivery conduit 143), the frame length increases by 2 to 5 mm. Typically, when positioned in its non-radial constraint configuration, the columnar 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, 10-25 mm or 12-20 mm. For some applications, the ratio of the length of the columnar 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.

[0190] Now for reference Figures 3A-3C , Figures 3A-3C This is a schematic diagram of an impeller 50 or a portion thereof according to some applications of the present invention. Typically, the impeller includes at least one outer helical elongated element 52 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. (As described in further detail below, typically, the central axial spring includes a tube 70 at a midpoint along its length. Furthermore, as stated below, the scope of this application includes the use of other axial structures instead of springs. Therefore, in some aspects, this application relates to "axial structure 54".) Typically, the impeller includes two or more helical elongated elements (e.g., three helical elongated elements, such as...). Figures 3A-3C (As shown). For some applications, the helical elongated element and the central axial spring are made of shape memory materials, such as nitinol shape memory alloys. Typically, each helical elongated element and the central axial spring is supported by a membrane 56 of material (e.g., an elastomer, such as polyurethane, and / or silicone) between them. For some applications, the membrane of the material includes nitinol sheets embedded therein, for example, to reinforce the membrane of the material. For illustrative purposes, the impeller in Figure 3A The image shows a membrane without this material. Figure 3B and Figure 3C Perspective views of the impeller are shown, in which a membrane of the material is supported between a helical elongated element and a spring.

[0191] Each helical elongated element, together with a membrane extending from the helical elongated element to the spring, defines a corresponding impeller blade, wherein the helical elongated element defines the outer edge of the blade, and the axial spring defines the axis of the impeller. Typically, the membrane of material extends along the spring and wraps around the spring. For some applications, the suture 53 (e.g., polyester suture, such as...) Figure 3B and Figure 3C The suture (as shown) is wound around a helical elongated element, for example as described in Schwammenthal's US10,864,310, which is incorporated herein by reference. Typically, the suture is configured to facilitate bonding between a membrane of material (typically an elastomer, such as polyurethane, or silicone) and a helical elongated element (typically a shape memory alloy, such as nitinol). For some applications, the suture (e.g., a polyester suture, not shown) is wound around a spring 54. Typically, the suture is configured to facilitate bonding between a membrane of material (typically an elastomer, such as polyurethane, or silicone) and a spring (typically a shape memory alloy, such as nitinol).

[0192] Figure 3C Enlarged views A and B illustrate two alternative arrangements in which the suture is secured around the helical elongated element 52. For some applications, the suture is secured around the outer surface of the helical elongated element, as shown in enlarged view A. Alternatively, the helical elongated elements define a groove 45 on their outer surface, and the suture is embedded within the groove, as shown in enlarged view B. Typically, by embedding the suture within the groove, the suture does not increase the outer profile of the impeller, and the outer profile of the impeller is defined by the outer surface of the helical elongated element.

[0193] Typically, the proximal end of spring 54 and the proximal end of helical elongated element 52 extend from the proximal bushing (i.e., sleeve support) 64 of the impeller, such that the proximal ends of spring 54 and helical elongated element 52 are positioned substantially at the same location and have a similar radial distance from the longitudinal axis of the impeller. Similarly, typically, the distal end of spring 54 and the distal end of helical elongated element 52 extend from the distal bushing 58 of the impeller, such that the distal ends of spring 54 and helical elongated element 52 are positioned substantially at the same location and have a similar radial distance from the longitudinal axis of the impeller. Typically, spring 54, as well as the proximal bushing 64 and distal bushing 58 of the impeller, define a cavity therethrough, such that the impeller defines a continuous cavity 62 therethrough (e.g., Figure 3C (As shown).

[0194] Now for reference Figure 4This figure 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 fitted onto the frame within at least a portion of the frame 34, as described below. Figures 12A-12B As described above. Depending on the application, the liner partially or completely overlaps the pump outlet pipe 24 above the liner-lined portion of the frame. In some applications, both the pump outlet pipe and the liner terminate before the distal end of the columnar portion 38 of the frame, leaving the distal portion of the columnar portion of the frame uncovered, as described below. Figure 13 As described above. For some applications, the pump outlet pipe continues to cover the distal tapered portion of the frame, as referenced. Figure 1D As stated above. Figure 4 In the illustrated application, the liner is nested within the columnar portion of the frame, and the pump outlet pipe 24 does not cover the columnar portion of the frame. However, the scope of this application includes references to... Figure 4 The described apparatus and methods apply to the following references. Figure 1D , Figures 12A-12B or Figure 13 Any of the applications described.

[0195] like Figure 4 As shown, typically, a gap G exists between the outer edge of the impeller 50 and the liner 39, even at the location of the largest impeller span. For some applications, it is desirable that the gap between the outer edge of the impeller blades and the liner 39 be relatively small so that the impeller can effectively pump blood from the subject's left ventricle into the subject's aorta. However, it is also desirable that the gap between the outer edge of the impeller blades and the inner surface of the frame 34 remain substantially constant throughout the rotation of the impeller within the frame 34, for example, to reduce the risk of hemolysis.

[0196] For some applications, when both the impeller and frame 34 are configured in a non-radial constrained configuration, the clearance G between the outer edge of the impeller and the liner 39 at the location of the largest impeller span 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, 0.05–1 mm or 0.1–0.4 mm. For some applications, when the impeller is configured in its non-radial constrained configuration, the impeller outer diameter at the location of the largest impeller 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, 7–10 mm or 8–9 mm. For some applications, when frame 34 is configured in its non-radial constrained configuration, the inner diameter of frame 34 (measured from the inside of liner 39 on one side of the frame to the inside of 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), such as 7.5–10.5 mm or 8.5–9.5 mm. For some applications, when frame 34 is configured in its non-radial 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), such as 8–13 mm or 9–12 mm.

[0197] Typically, the axial shaft 92 passes through the impeller cavity 62 along the axis of the impeller 50. More typically, the axial shaft is rigid, such as a rigid tube. (For some applications, at least part of the axial shaft is flexible, for example, as referenced...) Figures 20A-20C (As described above.) 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. The axial shaft itself is radially stabilized via a proximal radial support 116 and a distal radial support 118. Furthermore, 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 a relatively small gap (e.g., the gap described above) is maintained even during impeller rotation, even between the outer edge of the impeller blades and the inner surface of the frame 34.

[0198] Refer again Figures 3A-3CFor some applications, the impeller includes a plurality of elongated elements 67 extending radially from a central axial spring 54 to an outer helical elongated element 52. The elongated elements 67 are typically flexible but substantially not stretchable along the axis defined by the elongated elements 67. More typically, each of the elongated elements 67 is configured to be substantially non-resistant to compression. Instead, each elongated element 67 is configured to apply a tension force to the helical elongated element 52, preventing the helical elongated element 52 from moving radially outward, such that (in the absence of elongated elements 67) the gap between the helical elongated element 52 and the central axial spring 54 will be greater than the length of the elongated element 67. For example, the elongated elements 67 may comprise rope (e.g., polyester, and / or another polymer or a natural material containing fibers) and / or thread (e.g., nitinol thread, and / or thread made of different alloys or metals). In this way, the elongated elements prevent the impeller from expanding radially by applying a tension force to the helical elongated element.

[0199] For some applications, the elongated element 67 holds the helical elongated element 52 (which defines the outer edge of the impeller blades) within a given distance relative to the central axial spring 54. In this way, the elongated element 67 is configured to prevent the outer edge of the impeller from being forced radially outward due to the forces applied to the impeller during impeller rotation. In other words, the elongated element 67 acts as an element to prevent impeller expansion. The elongated element 67 is thus configured to maintain a gap between the outer edge of the impeller blades and the inner surface of the frame 34 during impeller rotation. 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 67 is typically folded in half (i.e., extending radially from the central axial spring 54 to the outer edge of the helical elongated element 52 and then returning from the helical elongated element to the central axial spring). For some applications, multiple elongated elements 67 are formed from a single rope or a single line, wherein each elongated element 67 extends from the spring to a corresponding helical elongated element 52 and returns to the central axial spring 54.

[0200] For some applications, the impeller is manufactured as follows: The proximal bushing 64, the distal bushing 58, and the 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 a tube of shape memory material, which is cut and shaped, for example, using a technique substantially similar to that described in Schwammenthal's US 10,039,874. Typically, a spring 54 is inserted into the cut and shaped tube such that the spring extends along the length of the tube at least from the proximal bushing to the distal bushing. For some applications, when the spring is in an axially compressed state, the spring is inserted into the cut and shaped tube, and the spring is configured to remain in place relative to the tube by applying radial forces on the proximal and distal bushings. Alternatively or additionally, multiple 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 such as nitinol. For some such applications, the spring is configured such that when the spring is set in a non-radial constraint configuration (where the spring is typically set in a non-radial constraint configuration during impeller operation), there is essentially no gap between the spring coil and its adjacent coil.

[0201] For some applications, after the spring 54 is inserted into the cut and shaped tube, the elongated element 67, as described above, is positioned to extend between the spring and one or more helical elongated elements 52, for example, in the following manner: A mandrel (e.g., a polyetheretherketone (PEEK) and / or polytetrafluoroethylene (PTFE) mandrel) is inserted through a cavity defined by the spring and bushing. A rope or thread is then wound such that the rope or thread (a) passes from the mandrel to a first helical elongated element in the helical elongated element 52, (b) returns from the first helical elongated element in the helical elongated element 52 to the mandrel, (c) circles the mandrel and reaches a second helical elongated element in the helical elongated element 52, (d) returns from the second helical elongated element in the helical elongated element 52 to the mandrel, and so on. Once the rope or thread has been wound from the mandrel to each helical elongated element 52 and back again, the ends of the rope or thread are joined together, for example, by tying them together. For some applications, a separate rope or thread is used for each helical elongated element 52. Typically, each rope or thread passes through and returns to the helical elongated element around the mandrel, with the ends of the rope tied together. For some applications, as shown, at the longitudinal central position of the spring 54, the spring is shaped to define a tube 70 (i.e., the spring does not define a coil at this position), and the rope or thread is wound around this tube. For some applications, the rope or thread is not wound around the tube and does not pass through the longitudinal axis of the impeller. Instead, the rope or thread is secured relative to the tube 70 by a fixing element 75 (e.g., a ring), as described below. Figure 3F As described in further detail.

[0202] For some applications, at this stage, suture 53 (e.g., polyester suture) is wound around the helical elongated element 52 to facilitate bonding between the film of the material (typically an elastomer, such as polyurethane, or silicone) and the helical elongated element 52 (typically a shape memory alloy, such as nitinol) in subsequent stages of impeller manufacturing. For some applications, suture (e.g., polyester suture, not shown) is wound around the spring 54. Typically, the suture is configured to facilitate bonding between the film of the material (typically an elastomer, such as polyurethane, or silicone) and the spring (typically a shape memory alloy, such as nitinol) in subsequent stages of impeller manufacturing.

[0203] Typically, at this stage, components such as Figure 3A The structure 59 is shown. This structure includes a cut and shaped tube defining a proximal bushing and a distal sleeve, a helical elongated element, and a spring (and optionally, the elongated element and a suture). The structure is immersed in a material defining a membrane 56. For some applications, the assembled structure is immersed in the material with a mandrel positioned through the cavity defined by the spring and bushing; however, it should be noted that the mandrel is not in the... Figure 3A As shown in the diagram. Typically, the material used to form the membrane is silicone and / or polyurethane (and / or similar elastomers), and the assembled structure is immersed in the material while it is in an uncured liquid state. The material is then cured, solidifying it, for example, by drying it. For some applications, the assembled structure is rotated while the material is drying, which typically helps to form a membrane of material with a substantially uniform thickness within each impeller blade. Once the material has dried, the mandrel is typically removed from the cavity defined by the bushing and spring.

[0204] Typically, the result of the above process is that a continuous membrane of material extends between each helical elongated element and the spring, and the continuous membrane of material also extends along the length of the spring to define a tube in which the spring is embedded. The portion of the membrane extending from each helical elongated element to the spring defines impeller blades. For applications where the impeller includes elongated elements 67, the elongated elements are typically embedded within these portions of the membrane.

[0205] Typically, the elongated element 67 is configured to limit the radial expansion of the impeller blades, as described in detail above. For some applications, the span of impeller blade expansion allowed by the elongated element is set using the following technique. As described above, the ends of a rope or line within the respective blade are tied together. Typically, the ends of the rope or line in each blade are tied such that the span of the impeller blade is set to be less than the desired impeller span, and such that there is some slack in the knots at the ends of the rope or line. Subsequently, by tightening the knots between the ends of the rope or line within each blade, the outer edges of the impeller blades are pulled apart to increase the span of the impeller blades. This process is repeated and the span of the impeller blades is measured until the desired impeller blade span is achieved. Subsequently, the structure 59 with the rope or line tied is immersed in an elastomeric material (made into a membrane 56 of the elastomeric material), and the elastomeric material is allowed to dry, such that the rope or line remains tied together at the ends to the desired span of the impeller blades.

[0206] Typically, impeller 50 is inserted into the left ventricle via a conduit, while impeller 50 is in a radially constrained configuration. In this 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 correspond to the shape changes of the helical elongated element and the central axial spring (both of which support the membrane). Typically, using a spring to support the inner edge of the membrane allows the membrane to change shape without breaking or collapsing because the spring provides a large surface area bound by the inner edge of the membrane. For some applications, using a spring to support the inner edge of the membrane reduces the diameter of the impeller that 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 making the spring axially elongated.

[0207] 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 some applications, when the impeller is radially constrained for insertion into the ventricle or for removal from the subject's body, the impeller is axially elongated by sliding the distal bushing distally along the axial shaft. For example... Figures 3A-3C As shown, after being released from the subject's body, the impeller exhibits its non-radial constraint configuration (where the impeller is typically set to a non-radial constraint configuration during impeller operation).

[0208] Note that, for illustrative purposes, in some figures, the impeller 50 is shown excluding information about... Figures 3A-3CAll features of the impeller shown and described. For example, some figures show the impeller excluding the stitching line 53 and / or the elongated element 67. The scope of this application includes the use of any apparatus and method described herein with regard to Figures 3A-3C Impellers with any of the features shown and described.

[0209] For some applications, the following technique is used to enhance the bonding of the elastomeric material to at least one helical elongated element in a manner that does not cause protrusion from the effective edge of the impeller blades. The helical elongated element is coated with a binder before immersion in the elastomeric material. Typically, a binder having at least two functional groups is selected, which are configured to bond to the helical elongated element and the elastomeric material, respectively. For example, a silane compound, such as n-(2-aminoethyl)-3-aminopropyltrimethoxysilane, containing a first functional group (e.g., (OH)) configured to bond to the helical elongated element (typically made of an alloy such as nitinol), and containing a second functional group (e.g., (NH2)) configured to bond to the elastomeric material, can be used. Typically, the functional groups in the binder 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, this layer of elastomeric material is the same or a similar elastomeric material used in membrane 56. For example, polycarbonate-based thermoplastic polyurethane, such as Aromatic Carbothane. TM (such as Aromatic Carbothane) TM 75A) can be used in film 56, and the coating can be the same polycarbonate-based thermoplastic polyurethane, or a similar polycarbonate-based thermoplastic polyurethane, such as Pellethane® (e.g., Pellethane® 90A).

[0210] For some applications, after the coating layer has been applied to the spiral elongated element, the coated spiral elongated element is sprayed with another layer of elastomeric material. Typically, the elastomeric material being sprayed is the same as or similar to the elastomeric material used as membrane 56. For example, polycarbonate-based thermoplastic polyurethane, such as Aromatic Carbothane. TM (such as Aromatic Carbothane) TM75A), can be used as film 56, and the material being sprayed can be the same polycarbonate-based thermoplastic polyurethane, or a similar polycarbonate-based thermoplastic polyurethane, such as Pellethane® (e.g., Pellethane® 90A). For some applications, the spray agent is applied to the helical elongated element to round it. Typically, when the helical elongated element has a circular cross-section, the elastomeric material forms a layer of substantially uniform thickness at the interface with the helical elongated element. For some applications, as described in the previous paragraph, the step of applying a layer of elastomeric material at least partially rounds the helical elongated element.

[0211] For some applications, after the spraying agent has been applied to the helical elongated element, structure 59 is immersed in an elastomer from which membrane 56 is made, for example, as described above. For some applications, the material used to manufacture the membrane is an elastic material having a limiting elongation greater than 300%, for example, greater than 400%. Typically, this material has a relatively low molecular weight. For some applications, this material has a melt flow index (an indirect measure of molecular weight) of at least 4, for example, at least 4.3. For some applications, this material has a limiting tensile strength exceeding 6000 psi, for example, exceeding 7000 psi, or exceeding 7500 psi. For some applications, this material is a thermoplastic polyurethane, for example, Carbothane. TM For some applications, Aromatic Carbothane is used. TM 75A. Typically, this material combines one or more of the following properties: no loss of outer diameter during immersion, fatigue resistance, resistance to deformation due to curling, and low loss of outer diameter during curling.

[0212] Based on the above description of applying membrane 56 to the helical elongated element, the scope of the invention includes any technique, whether by spraying, immersion, or different coating methods, of applying additional layers of the same elastomeric material, different elastomeric materials, and / or intermediate materials to the helical elongated element before immersing it into the elastomeric material used to manufacture membrane 56. For some applications, the additional layer of elastomeric material is configured to round the helical elongated element and / or serve as an intermediary to enhance the bonding between the helical elongated element and the membrane 56 of the material. For some applications, an intermediary material (e.g., silane) is configured to act as an intermediary to enhance the bonding between the helical elongated element and the membrane 56 of the material.

[0213] Now for reference Figure 3D and Figure 3E , Figure 3D and Figure 3EThis is a schematic diagram of impeller 50. According to some applications of the invention, the impeller includes a single integrated anti-over-expansion element 72 defining a plurality of elongated elements 67. For illustrative purposes, Figure 3D and Figure 3E An impeller without the material membrane 56 is 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 rope and / or wire around a spring 54, the ring 73 of element 72 is positioned around the spring, for example, by positioning it around a tube 70, which is typically positioned longitudinally at the center of the spring. The ends of the respective elongated elements 67 are then coupled to the respective helical elongated elements 52. As described above, the elongated elements 67 are typically flexible but substantially not stretchable along the axis defined by the elongated elements. More typically, each of the elongated elements 67 is configured to be substantially non-resistant to compression. More precisely, each elongated element 67 is configured to apply a tension force to the helical elongated elements 52, which prevents the helical elongated elements 52 from moving radially outward, such that (in the absence of elongated elements 67) the gap between the helical elongated elements 52 and the central axial spring 54 will be greater than the length of the elongated elements 67. When forces acting on the impeller would cause the helical elongated element 52 to move radially outward (in the absence of the elongated element 67), an anti-overexpansion element is configured to prevent the impeller from expanding radially. Typically, a corresponding elongated element 67 is disposed within each impeller blade and configured to prevent the impeller blade from expanding radially. For some applications, element 72 is made of polyester and / or another polymer or a fiber-containing natural material and / or nitinol (or a similar shape memory alloy).

[0214] Note that the scope of this application includes those with... Figures 3D-3E A single integrated anti-overextension element 72 is used with impellers of different structures as shown. For example, the single integrated anti-overextension element 72 can be used with an impeller having an axial structure with a different construction than spring 54. Typically, the axial structure defines a cavity therethrough, such that the impeller defines a cavity 62 therethrough.

[0215] Now for reference Figure 3FThis is a schematic diagram of impeller 50. According to some applications of the invention, the impeller includes a fixing element 75 configured to fix an elongated element 67 relative to tube 70. In some applications, the rope or line including the elongated element 67 does not wrap around tube 70 and does not pass through the longitudinal axis of the impeller. Instead, the rope or line is fixed relative to tube 70 by the fixing element 75. Typically, the rope or line is fixed to the outer surface of tube 70 at the location closest to the maximum span of the helical elongated element (to which the end of the rope or line is tethered). In some applications, the fixing element includes a ring, as shown. In some such applications, the ring defines small notches (or eyelets) 80 through which the rope or line passes between the ring and tube 70.

[0216] Now for reference Figure 3 Gi and Figure 3 Gii These figures are images of an impeller 50 according to some applications of the present invention. As shown, for some applications, the impeller is manufactured using the method described above, with adjacent blades 51 of the impeller 50 shaped to define a continuous U-shaped surface. As shown by curve 55, curve 55 is added along at least a portion of the length of the impeller. Figure 3 Gii As the membrane 56 of the elastomeric material transitions from one blade to an adjacent blade, the membrane forms a continuous U-shaped curve. Note that even at the spring 54 extending along the axis of the impeller, the curvature of the membrane of the material is substantially uninterrupted. For some applications, the membrane of the material exhibits the aforementioned curvature due to the impeller being formed in the manner described above. Typically, by defining a continuous U-shaped surface, the impeller blades are configured to provide a smooth streamline (along which blood flows through the impeller), thereby improving the efficiency of the impeller in pumping blood and / or reducing the risk of hemolysis compared to the case where the continuous surface is not defined for adjacent blades (e.g., compared to the case where the curvature is interrupted at the spring 54). For some applications, substantially similar impellers are used, wherein the impeller has an axial structure configured differently from the spring 54 (e.g., a cylindrical axial structure). Typically, the axial structure defines a cavity through which the impeller defines a cavity 62 through which it passes. Alternatively, the impeller includes the spring 54 (which includes a tube 70) as the axial structure, as shown.

[0217] When viewed from the distal end of the impeller, the pressure side (i.e., the side that pushes blood during impeller operation) of each blade is convex in the distal region of the impeller, transitions to a substantially radial orientation in the region of the elongated element 67, and then becomes concave in the proximal region of the impeller. (For illustrative purposes, the opposite sides (i.e., the "non-pressure sides") of the impeller blades are...) Figure 3 Gii(This is indicated in the diagram.) Therefore, when in use, blood pumped by the impeller is first pumped by the convex impeller surface and then by the concave impeller surface. For some applications, the elongated element 67 is positioned approximately halfway along the length of the impeller blade and is configured to facilitate the transition of the film of the material from having a convex curvature to having a concave curvature. Thus, typically, in the region of the elongated element 67 within the impeller blade, the blade is substantially radially oriented. Typically, by defining a concave surface in the proximal region of the impeller, the pressure side of the impeller blade is configured to increase blood flow and / or pressure even after blood has flowed and / or been pressured in the distal region of the impeller. Optionally (not shown), the pressure side of each blade of the impeller (i.e., the side that pushes blood during impeller operation) is concave in the distal region of the impeller, transitions to substantially radial orientation in the region of the elongated element 67, and then becomes convex in the proximal region of the impeller.

[0218] Now for reference Figure 5A and Figure 5B These figures are schematic diagrams of the impeller 50 and frame 34 of a ventricular assist device 20, respectively in its non-radial restraint and radial restraint states according to some applications of the invention. During catheter insertion into the subject's body, the impeller and frame are typically configured in a radial restraint state, and during impeller operation within the subject's left ventricle, the impeller and frame are configured in a non-radial restraint state. As described above, typically, the pump outlet pipe 24 is disposed over at least a portion of the frame and extends proximally from at least a portion of the frame. However, for illustrative purposes, in Figures 5A-5B The image shows the frame and impeller without the pump outlet pipe 24.

[0219] like Figure 5B As shown, the frame and impeller are typically held in a radially constrained configuration by the delivery duct 143. Typically, in a 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), for example, 15-30 mm or 20-25 mm. More typically, in a non-radially constrained configuration of the impeller, the length of the impeller is greater than 8 mm (e.g., greater than 10 mm) and / or less than 18 mm (e.g., less than 15 mm), for example, 8-18 mm or 10-15 mm. Furthermore, typically, when the impeller and frame 34 are arranged in a radially constrained configuration (e.g.... Figure 5B As shown), 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).

[0220] As described above, typically, the axial shaft 92 is connected via the impeller cavity 62 (cavity 62 in...) Figure 3C (As shown in the diagram) the axis passing through the impeller 50. Typically, the proximal bushing 64 of the impeller is connected to the shaft via a coupling element 65, 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. The axial shaft itself is radially stabilized via a proximal radial support 116 and a distal radial support 118.

[0221] Typically, the connecting portion 31 of the frame 34 is connected to the proximal radial support 116, for example, via a snap-fit ​​connection and / or via welding. Typically, at the distal end of the frame 34, the distal strut joint 33 is placed into a recess defined by the outer surface of the distal radial support 118, the recess being shaped to conform to the shape of the distal strut portion. As shown, the proximal end of the distal end element 107 (which defines the distal end portion 120) typically holds the distal strut portion in its closed configuration surrounding the outside of the distal radial support 118. For some applications, the device includes a distal extension 121 extending distally from the distal radial support. Typically, this extension is configured to reinforce the area of ​​the distal end element that the distal end of the shaft 92 moves into (e.g., the axial shaft receiving tube 126 or a portion thereof described below).

[0222] As described above, the axial shaft 92 is radially stabilized via the proximal radial support 116 and the distal radial support 118. Furthermore, 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, as described above, even the relatively small gap (e.g., the gap described above) between the outer edge of the impeller blades and the inner surface of the frame 34 is maintained during impeller rotation. For some applications, the axial shaft 92 is made of stainless steel, and the proximal support 116 and / or the distal support 118 are made of hardened steel. Typically, when the impeller and frame are coiled (i.e., radially constrained) for insertion into the subject's body, the distal bushing 58 of the impeller is configured to slide distally along the axial shaft, causing the impeller to become axially elongated while the proximal bushing remains axially fixed relative to the axial shaft. More generally, by sliding the distal bushing over the axial shaft while the proximal bushing remains axially fixed relative to the axial shaft, the impeller changes from its radially constrained configuration to its non-radially constrained configuration, and vice versa.

[0223] Typically, the impeller itself is not directly housed within any radial or thrust support. Instead, supports 116 and 118 act as radial supports relative to the axial shaft. Typically, the pump section 27 (and more generally, the ventricular assist device 20) does not include any thrust support configured to be disposed within the subject's body and configured to resist the thrust generated by the rotation of the impeller. For some applications, one or more thrust supports are disposed outside the subject's body (e.g., in situations such as...). Figure 1A , Figure 7A-Figure 7Bii Within the motor unit 23 shown, resistance to the thrust generated by the rotation of the impeller is provided solely by one or more thrust supports located outside the subject's body. For some applications, mechanical and / or magnetic elements are configured to hold the impeller within a given axial position range. For example, a magnet (e.g., magnet 82, hereinafter referred to) located at the proximal end of the drive cable 130 (e.g., outside the subject's body). Figure 7A (As described) can be configured to apply axial movement to the impeller and / or hold the impeller within a given axial position range.

[0224] Now for reference Figure 6A and Figure 6B These figures are schematic diagrams of a ventricular assist device 20 at various stages of its motion cycle relative to the frame 34 of the ventricular assist device, according to some applications of the invention. For some applications, when the impeller pumps blood through the tube 24 by rotation, an axial shaft 92 (on 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 axially reciprocating manner, as shown below. Figure 7A-Figure 7Bii Further detailed description. Alternatively or additionally, the impeller and axial shaft are configured to reciprocate axially within the frame 34 in response to forces acting on the impeller, without requiring active drive of the axial shaft to move in a reciprocating manner. Typically, during a subject's cardiac cycle, the pressure gradient between the left ventricle and the aorta changes from approximately zero during ventricular systole (hereinafter referred to as "systole") to a relatively large pressure gradient (e.g., 50 mmHg–70 mmHg) during ventricular diastole (hereinafter referred to as "diastole"). For some applications, due to the increased pressure gradient resisted by the impeller pumping during diastole (and because the drive cable 130 is stretchable), the impeller is pushed distally relative to the frame 34 during diastole compared to its position relative to the frame 34 during systole. Consequently, the axial shaft moves forward because the impeller is connected to it. During systole, the impeller (and consequently the axial shaft) returns to its systolic position. In this way, the axial reciprocating motion of the impeller and the axial shaft is generated passively, that is, it is not necessary to actively drive the axial shaft and impeller to make them undergo this motion. Figure 6A The impeller and axial shaft are shown positioned at their typical contraction point, and Figure 6B The impeller and axial shaft are shown in their typical diastolic position.

[0225] In some applications, the portion of the axial shaft in contact with the proximal support 116 and the distal support 118 changes continuously due to its axial reciprocating motion. In some such applications, assuming all else is equal, the frictional force exerted on the axial shaft by the supports is distributed over a larger area of ​​the axial shaft compared to when the axial shaft does not move relative to the supports, thereby reducing wear on the axial shaft. Alternatively or additionally, by reciprocating relative to the supports, the axial shaft removes any residue, such as blood residue, from the interface between the axial shaft and the supports.

[0226] For some applications, when the frame 34 and impeller 50 are in their non-radially constrained configuration (e.g., when the frame and impeller are deployed in the left ventricle), the length of the frame exceeds the length of the impeller by at least 2 mm (e.g., at least 4 mm, or at least 8 mm). Typically, the proximal support 116 and the distal support 118 are each 2 mm to 4 mm in length (e.g., 2 mm to 3 mm). More typically, the impeller and axial shaft are configured to reciprocate axially within the frame at least along the length of each of the proximal and distal supports, or at least along twice the length of each of these supports. Thus, during the reciprocating axial movement of the axial shaft, either side of each of these supports is wiped clean.

[0227] For some applications, the range of impeller motion is as follows: Figures 6A-6B As shown, where Figure 6A The impeller is positioned closest to the heart during the cardiac cycle (typically, the impeller is positioned in this order during systole), and Figure 6B This indicates the impeller's furthest position during the cardiac cycle (typically, the impeller is positioned this way during diastole). For example... Figure 6A As shown, for some applications, at the closest position to the impeller, the proximal end of the impeller is positioned at location I. P At that location, I P Within the proximal conical segment of frame 34. (e.g.) Figure 6B As shown, for some applications, at the farthest position of the impeller, the far end of the impeller is set at position I. D At that location, I D At the distal end of the columnar segment of frame 34. For the purposes of this application, the frame from I P To I DThe entire segment of the frame can be considered to house the impeller, as this entire segment typically houses at least a portion of the impeller during at least a portion of the cardiac cycle. Typically, the segment with the largest impeller span is located within the cylindrical portion of the frame 34 throughout the entire cardiac cycle. However, during at least a portion of the cardiac cycle, the proximal portion of the impeller is typically located within the proximal conical segment of the frame.

[0228] Refer again Figure 6A and Figure 6B And also refer to Figure 6C , Figure 6C This is an enlarged schematic diagram of a distal end element 107 according to some applications of the present invention, comprising an axial shaft receiving tube 126 of a ventricular assist device 20 and a distal end portion 120. Typically, the distal end element 107 is a single integrated element comprising both the axial shaft receiving tube 126 and the distal end portion 120. For some applications, the distal end element 107 is configured to be flexible, 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 element 107 may be made of silicone, polyethylene terephthalate (PET), and / or polyether block amide (e.g., PEBAX®). For some applications, the distal end portion defines a cavity 122 therethrough. For some such applications, during insertion of the ventricular assist device into the left ventricle, the guide wire 10 ( Figure 1B First, it is inserted into the left ventricle according to, for example, known techniques. Then, the distal portion of the ventricular assist device is guided into the left ventricle by advancing the distal portion of the guide wire, wherein the guide wire is disposed within the cavity 122. For some applications, a duckbill valve 390 (or a hemostatic valve of a different type) is disposed at the distal end of the cavity 122 of the distal portion 120.

[0229] Typically, during insertion of the ventricular assist device into the subject's ventricle, the delivery catheter 143 is positioned over the impeller 50 and frame 34, and the impeller and frame are held in their radially constrained configuration. For some applications, a distal end element 107 extends distally from the delivery catheter during insertion into the subject's ventricle. For some applications, at the proximal end of the distal end element, the distal end element has a flared portion 124 that acts as a stop and prevents the delivery catheter from being advanced beyond the flared portion.

[0230] It should be noted that, Figures 6A-6CThe external shape of the distal distal portion (and some other figures) is shown as defining a complete loop, wherein the distal end of the distal distal portion (within which the duckbill valve 390 is disposed) spans the more proximal portion of the distal distal portion. Typically, due to the guide wire inserted therethrough (during insertion of the ventricular assist device into the left ventricle), the distal distal portion remains partially extended, even after the guide wire is removed from the distal distal portion. Typically, the partial extension of the distal distal portion is such that when the distal distal portion is positioned in the left ventricle, in the absence of external force acting on the distal distal portion, the distal distal portion does not define a complete loop, for example as... Figure 1B , Figure 15D and Figure 16A As shown. For some applications, in order to insert the lead wire through the distal end portion, the following example is used, for instance, as shown in the reference. Figures 23A-23C The straightening element 270 is described in further detail below. Other aspects of the shape of the distal end portion will be described in further detail below.

[0231] Now for reference Figure 6D and Figure 6E These are schematic diagrams of impeller 50. According to some applications of the invention, the proximal bushing 64 of the impeller is connected to a connecting element 65, which extends proximally to act as a stop. Figure 6D This shows the impeller in the contraction phase of its motion cycle, and Figure 6E This illustrates the impeller in the expansion phase of its motion cycle. Typically, the connecting element extends proximally to prevent the central region of the impeller (where it is at its maximum span) from sliding proximally into the proximal tapered portion of frame 34. For example, during the contraction phase of the impeller's motion cycle (in... Figure 6D (As shown in the diagram), if the impeller slides further proximally beyond a given amount, the proximal-extending connecting element will contact the proximal radial support 116, thereby preventing further proximal movement of the impeller. For some applications, the connecting element extends proximally such that its total length is greater than 1.5 mm, for example, greater than 4 mm. For some applications (not shown), as an alternative or addition to the proximal-extending connecting element, a separate stop element is provided proximally on the axial shaft relative to the connecting element. Typically, the stop is configured as described with reference to the proximal-extending connecting element. That is, if the impeller slides further proximally beyond a given amount, the stop element will contact the proximal radial support 116, thereby preventing further proximal movement of the impeller.

[0232] Now for reference Figure 7AThis is a schematic exploded view of the motor unit 23 of a ventricular assist device 20 according to some applications of the present invention. As shown, the motor unit is typically a handle configured to be disposed outside the subject's body and to house the motor. Therefore, the motor unit may alternatively be referred to as a handle unit.

[0233] For some applications, console 21 ( Figure 1A The computer processor 25, which controls the rotation of the impeller 50, is also configured to control the reciprocating motion of the axial shaft. Typically, both types of motion are generated using the motor unit 23. The scope of the invention includes controlling reciprocating motion at any frequency. For some applications, an indication of a 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.

[0234] Typically, motor unit 23 includes a motor 74 configured to apply rotational motion to impeller 50 via drive cable 130. As described further below, typically, the motor is magnetically coupled to the drive cable. For some applications, axial motion driver 76 is configured to drive the motor to move in an axial reciprocating motion (as indicated by double-headed arrow 79). Typically, due to the magnetic coupling between the motor and the drive cable, the motor applies reciprocating motion to the drive cable, which in turn applies that 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 pressure gradients resisted by the impeller pumping blood. Typically, for such applications, motor unit 23 does not include axial motion driver 76.

[0235] In some applications, the magnetic coupling between the motor and the drive cable is as follows: Figure 7A As shown. Figure 7AAs shown, at least one or more drive magnets 77 (e.g., two 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 gasket 85 is adhered to the inner surface of the ring 81 between the two drive magnets. At least one driven magnet 82 is disposed between the drive magnets such that there is axial overlap between the drive magnets and the driven magnets. 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 a drive cable 130. For example, the driven magnet may be cylindrical and define a hole through it, and the pin 131 may be adhered to the inner surface of the driven magnet defining 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 by a line 83 that bisects the cylinder, as shown. For some applications, the driven magnet is housed within a cylindrical housing 87. Typically, a pin 131 defines a cavity 133 through which a guide wire 10 is inserted.

[0236] Note that in Figure 7A In the illustrated application, the driving magnet is positioned outside the driven magnet. However, the scope of this application includes configurations that reverse the driving and driven magnets (with necessary modifications). For example, the proximal end of the drive cable may be coupled to two or more driven magnets arranged around the driving magnet such that there is axial overlap between the driven and driving magnets.

[0237] As described above, typically, the cleaning system 29 (such as...) Figure 1A (As shown) Used with ventricular assist device 20. Typically, motor unit 23 includes an inlet port 86 and an outlet port 88 for use with a cleaning system. For some applications, cleaning fluid is continuously or periodically pumped into the ventricular assist device via inlet port 86 and pumped out of the ventricular assist device via outlet port 88. Other aspects of the cleaning system will be described below.

[0238] Typically, magnet 82 and pin 131 are held in a fixed axial position within motor unit 23. (For some applications, magnet 82 does have a small degree of axial and / or rotational freedom relative to other components of the motor unit, such as drive magnet 77. For some applications, this movement is measurable, as described in further detail below.) Typically, the proximal end of the drive cable is coupled to pin 131 and thereby held in a fixed axial position relative to the pin. Typically, drive cable 130 extends from pin 131 to axial shaft 92 and thus at least partially fixes the axial position of the axial shaft, which in turn fixes the impeller 50. For some applications, the drive cable is somewhat stretchable. For example, the drive cable may be made of stretchable coiled wire, as described in further detail below. Drive cables typically allow the axial shaft (and consequently the impeller) to present a certain range of axial positions (becoming more or less stretched by the drive cable), but limit the axial movement of the axial shaft and impeller to a certain range of motion (by keeping the proximal end of the drive cable in a relatively fixed axial position, and limiting the stretchability of the drive cable).

[0239] Now for reference Figure 7Bi and Figure 7 Bii These figures are schematic diagrams of motor unit 23 according to some applications of the present invention. Generally, as... Figure 7Bi and Figure 7 Bii The motor unit 23 shown is similar to Figure 7A The motor unit shown, unless otherwise specified, is as follows: Figure 7Bi and Figure 7 Bii The motor unit 23 shown includes and Figure 7A The motor unit 23 shown is a similar component. For some applications, the motor unit includes a radiator 90 configured to dissipate heat generated by the motor. Alternatively or additionally, the motor unit includes a ventilation port 93 configured to further dissipate 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 the rotational and / or axial reciprocating motion of components of the ventricular assist device.

[0240] As described above, for some applications, the impeller 50 and the axial shaft 92 are configured to reciprocate axially within the frame 34 in response to forces acting on the impeller, without requiring active driving of the axial shaft to move in a reciprocating manner. Typically, during a subject's cardiac cycle, the pressure gradient between the left ventricle and the aorta changes from approximately zero during systole to a relatively large pressure gradient during diastole (e.g., 50 mmHg–70 mmHg). For some applications, due to the increased pressure gradient resisted by the impeller pumping during diastole (and because the drive cable is stretchable), the impeller is pushed distally relative to the frame 34 during diastole, in accordance with its position relative to the frame 34 during systole. Furthermore, since the impeller is connected to the axial shaft, the axial shaft moves forward. During systole, the impeller (and consequently the axial shaft) returns to its systolic position. In this way, the axial reciprocating motion of the impeller and the axial shaft is generated passively, that is, it is not necessary to actively drive the axial shaft and impeller to make them undergo this motion.

[0241] Now for reference Figure 8A This figure is a graph showing the change in the length of the drive cable of a ventricular assist device (VAD) as a function of the pressure gradient resisted by the VAD impeller (as measured experimentally). The impeller and drive cable described herein are used to pump a glycerol-based solution through chambers configured to reproduce the left ventricle and aorta, and the solution has properties similar to blood (e.g., density and viscosity). The pressure gradient resisted by the impeller pump varies in a pulsating manner to represent the pulsation of the pressure gradient typically resisted by the impeller as it pumps blood from the left ventricle to the aorta. Simultaneously, the movement of the drive cable is imaged, and the change in drive cable length is determined via image analysis. Figure 8A The graph shown illustrates how the measured drive cable length changes with the pressure gradient. Figure 8A As shown, as the pressure gradient resisted by the impeller pump increases, the drive cable becomes longer and longer. Figure 8A As shown and described above, typically, in response to changes in pressure resisted by the impeller pumping blood (e.g., the pressure difference between the left ventricle and the aorta), the impeller reciprocates relative to the frame 34. This movement of the impeller, in turn, causes the drive cable 130 to elongate more or less.

[0242] For some applications, during the operation of the ventricular assist device, console 21 ( Figure 1AThe computer processor 25 is configured to measure the pressure applied to the impeller (indicating the pressure differential between the left ventricle and the aorta) by measuring the tension in the drive cable 130 and / or the indication of the axial movement of the drive cable. In some applications, based on the measured indications, the computer processor detects events in the subject's cardiac cycle, determines the subject's left ventricular pressure, and / or determines the subject's cardiac afterload. In some applications, the computer processor controls the rotation of the impeller and / or, in response, controls the axial reciprocating motion of the axial shaft.

[0243] Refer again Figure 7A For some applications, the ventricular assist device 20 includes a sensor 84. For example, the sensor may include a magnetometer (e.g., a Hall sensor) disposed within the motor unit 23. Figure 7A As shown. (In some cases, sensor 84 is referred to as magnetometer 84.) In some applications, the axial reciprocating motion of the impeller causes a measurable reciprocating motion of the internal driven magnet 82 relative to one or more external drive magnets 77 because the driven magnet is held in place relative to the drive magnet by magnetic coupling rather than a rigid mechanical connection. Note that typically, the axial motion of the magnet is substantially less than the axial motion of the impeller because the entire range of motion of the impeller is not transmitted along the length of the drive cable. In some applications, the magnetometer measures the change in the magnetic field generated by one of the magnets in order to measure the axial motion of the drive cable 130 and, consequently, determine the pressure that the impeller pumps against. For example, the internal driven magnet 82 may be longer in the axial direction than the external drive magnet 77. Because the internal magnet is longer than the external magnet, the magnetic field lines emanating from the internal magnet are not transmitted to the external magnet, and the magnetic flux generated by these field lines, as measured by the magnetometer, varies due to the drive cable, and consequently causes axial movement of the internal magnet. During operation, motor 74 rotates, thereby generating an AC signal in the magnetometer, typically with a frequency between 200 Hz and 800 Hz. Typically, as the tension in the drive cable changes due to the subject's cardiac cycle, this generates a low-frequency envelope in the signal measured by the magnetometer, typically with a frequency of 0.5 Hz to 2 Hz. For some applications, a computer processor measures the low-frequency envelope and derives the subject's cardiac cycle from the measured envelope.

[0244] For some applications, the magnetometer measurements are initially calibrated such that the change in magnetic flux per unit pressure change resisted by the impeller pump (i.e., per unit change in the pressure difference between the left ventricle and the aorta, or per unit change in the pressure gradient) is known. It is known that, in most subjects, the left ventricular pressure equals the aortic pressure during systole. Therefore, for some applications, the subject's aortic pressure is measured, and then the subject's left ventricular pressure at a given time is calculated by a computer processor based on: (a) the measured aortic pressure, and (b) the difference between the magnetic flux measured by the magnetometer at that time and the magnetic flux measured by the magnetometer during systole (when the pressure in the left ventricle is assumed to be equal to the aortic pressure). For example, the subject's aortic pressure can be measured by measuring the pressure in the channel 224 defined by the delivery catheter 143, as described in further detail below. For some applications, the techniques described above are used to determine alternative or additional physiological parameters. For example, events in the subject's cardiac cycle and / or the subject's cardiac afterload can be determined.

[0245] For some applications, techniques similar to those described in the preceding paragraph are typically used, but as an alternative or supplement to the use of a magnetometer, different parameters are measured to determine left ventricular blood pressure at a given time (and / or different physiological parameters, such as events in the subject's cardiac cycle and / or the subject's cardiac afterload). For example, typically, there is a relationship between the amount of power (and / or current) required to drive the impeller to rotate at a given rate of rotation and the pressure differential generated by the impeller. (Note that a portion of the pressure differential generated by the impeller is used to overcome the pressure gradient counteracted by the impeller pumping, while another portion is used to actively pump blood from the left ventricle to the aorta by creating a positive pressure differential between the left ventricle and the aorta. Furthermore, the relationship between these components typically changes during the cardiac cycle.) For some applications, calibration measurements are performed such that the relationship between (a) the motor power (and / or current) consumed to rotate the impeller at a given rate of rotation and (b) the pressure differential generated by the impeller is known. For some applications, the subject's aortic pressure is measured, and a computer processor calculates the subject's left ventricular pressure at a given time based on (a) the measured aortic pressure, (b) the motor power (and / or current) consumption required to rotate the impeller at a given rotational rate at a given time, and (c) a predetermined relationship between the motor power (and / or current) consumption required to rotate the impeller at a given rotational rate and the pressure difference generated by the impeller. For some applications, the above technique is performed while keeping the impeller rotational rate constant. Alternatively or additionally, the impeller rotational rate is varied, and the variation in the impeller rotational rate is taken into account in the above calculations. For some applications, the above technique is used to determine alternative or additional physiological parameters. For example, events in the subject's cardiac cycle and / or the subject's cardiac afterload can be determined.

[0246] Typically, tube 24 has a known cross-sectional area (when the tube is open due to blood flow). For some applications, the flow rate through tube 24 generated by the impeller is determined based on a defined pressure differential generated by the impeller and the known cross-sectional area of ​​the tube. For some applications, this flow rate calculation incorporates calibration parameters to account for factors such as flow resistance, which correspond to the specificity of the ventricular assist device (or type of ventricular assist device) being performed. For some applications, a ventricular pressure-volume loop is derived based on a defined ventricular pressure.

[0247] Refer again Figure 7AFor some applications, in addition to the magnetometer 84 configured to measure the magnetic flux density generated by the driven magnet, a second magnetometer 84A (e.g., a second Hall sensor) measures the indication of the magnetic flux density generated by the driving magnet. In some applications, the second magnetometer measures the magnetic flux density of the motor, indicating the magnetic flux density cycle of the driving magnet, since the motor directly drives the driving magnet to rotate. Typically, torque is generated on the impeller when it rotates, such as when pumping blood. More typically, the strength of the torque depends on various parameters, such as the flow rate generated by the impeller, the impeller's rotational speed, and / or the pressure gradient resisted by the impeller pumping. In some applications, the torque generated on the impeller produces a measurable torque on the internal driven magnet 82 relative to the external driving magnet 77, because the driven magnet is held in place relative to the driving magnet by magnetic coupling rather than a rigid mechanical connection. Note that the torque generated on the driven magnet is typically much smaller than the torque generated on the impeller, because the torque generated on the impeller is not transmitted along the length of the drive cable. However, typically, the torque generated on the impeller is transmitted at least in part to the driven magnet via the drive cable.

[0248] The torque transmitted to the driven magnet typically causes a phase difference between the signal measured by magnetometer 84 (which measures the magnetic flux density of the driven magnet) and the signal measured by second magnetometer 84A (which measures the magnetic flux density of the motor and / or drive magnet). In some applications, this causes a change in the phase difference between the signal measured by magnetometer 84 and the signal measured by second magnetometer 84A when the torque on the impeller changes. In some applications, a computer processor detects the change in the aforementioned phase difference and determines physiological parameters of the subject in at least a partial response to the change in the phase difference. For example, based at least in part on the change in the phase difference, the computer processor can determine the difference between the subject's left ventricular pressure and the subject's aortic pressure, the subject's left ventricular pressure, events in the subject's cardiac cycle, the subject's cardiac afterload, and / or different physiological parameters. In some applications, the techniques described in this paragraph are used as alternatives to the aforementioned techniques for determining physiological parameters using magnetic flux density measurements and / or power consumption measurements. Alternatively, two or more of these techniques may be used in combination. For example, physiological parameters of a subject can be determined based on a mathematical model that includes two or more measurements, and / or one of the techniques can be used to verify estimates of physiological parameters of a subject made using another of the techniques.

[0249] Now for reference Figure 8B and Figure 8C According to some applications of the present invention, they show graphs illustrating the correlation between the phase difference signal and the pressure gradient resisted by the impeller 50 pump.

[0250] Figure 8BThe graphs shown illustrate the results of an experiment in which a ventricular assist device, as described herein, was used to pump blood against a corresponding pressure gradient within a static extracorporeal system (i.e., the pressure gradient was constant for each measurement). The pressure gradient resisted by the impeller pump was estimated using a linear regression model based on the phase difference signal, the flux amplitude signal, and the current consumed by the motor. Figure 8B The graph shown illustrates the relationship between the estimated pressure gradient and the measured pressure gradient. As illustrated, the linear regression model, combined with phase difference measurements, provides a reliable method for estimating the pressure gradient resisted by the impeller pump.

[0251] Figure 8C The graphs shown illustrate the results of an experiment in which a ventricular assist device, as described herein, was used to pump blood against a corresponding pressure gradient within a static extracorporeal system (i.e., where the pressure gradient changes pulsatilely). The pressure gradient resisted by the impeller pumping was estimated using a spatial state model based on the phase difference signal, the flux amplitude signal, and the current consumed by the motor. Figure 8C The diagram shows the estimated pressure gradient superimposed on the measured pressure gradient. As illustrated, the spatial state model combined with phase difference measurements provides a reliable method for estimating the pressure gradient resisted by the impeller pump.

[0252] According to the above, and in some applications of the invention, the magnetic phase difference between one or more driven magnets and one or more driving magnets is measured, and physiological parameters of a subject are determined at least in part in response to this magnetic phase difference. For example, based at least in part on changes in the phase difference, a computer processor can determine the difference between the subject's left ventricular pressure and the subject's aortic pressure, the subject's left ventricular pressure, events in the subject's cardiac cycle, the subject's cardiac afterload, and / or different physiological parameters. For some applications, the physiological parameters are determined based on a combination of phase difference measurements and one or more additional measurements, such as magnetic flux amplitude measurements, motor power consumption, and / or motor current consumption. Typically, such measurements are combined in a mathematical model, such as a linear regression model, and / or a spatial state model.

[0253] Now for reference Figures 9A-9G These are schematic views of various views of a motor unit support 170 configured to support the motor unit 23 on a patient's leg 172 for some applications according to the invention. For some applications, the ventricular assist device is inserted into the patient via a femoral access point 173, and the motor unit support is configured to rest on the patient's thigh below the femoral access point, as shown. Typically, the motor unit support is configured to at least partially insulate the patient's leg from vibrations and / or heat generated by the motor unit during operation of the motor unit.

[0254] For some applications, the motor unit support includes a curved base 176 configured to rest on a patient's thigh, and a motor unit dock 178 on which the motor unit rests. Typically, a gap 179 exists between the motor unit dock and the curved base of the motor unit support, allowing the patient's leg to be separated from the motor unit through the gap. This gap serves to at least partially insulate the patient's leg from vibrations and / or heat generated by the motor unit during operation. For some applications, the motor unit support is configured to receive a strap 174 through the gap for securing the motor unit support to the patient's leg. Typically, the strap is elastic and / or adjustable to fit the patient's leg.

[0255] Typically, the motor unit support includes a coupling element 180 for connecting the motor unit dock to the motor unit (e.g., in...). Figure 9D (As shown in the diagram). As described above, for some applications, the motor unit includes a ventilation port 93, which is configured to help dissipate heat generated by the motor. For some such applications, the coupling element includes a snap-fit ​​coupling element, such as... Figure 9E As shown, the snap-fit ​​coupling element is configured to connect the motor unit dock to the motor unit by snapping the coupling element into the ventilation port of the motor unit. For some applications, the motor unit includes ventilation ports on both sides of the motor unit, allowing connection to the motor unit dock from either side of the motor unit.

[0256] Now for reference Figure 10A , Figure 10B and Figure 10C These figures are schematic diagrams of the drive cable 130 of a ventricular assist device 20 according to some applications of the present invention. Typically, the rotational motion of the motor is transmitted to the axial shaft via the drive cable. Typically, the drive cable extends from the motor unit 23 (which is typically disposed outside the subject's body) to the proximal end of the axial shaft 92 (e.g., in...). Figure 5A The left enlarged portion shows the connection between the distal end of the drive cable and the proximal end of the axial shaft. For some applications, the drive cable comprises multiple wires 134 arranged in a coiled configuration to provide sufficient strength and flexibility to allow a portion of the cable to remain within the aortic arch (e.g., corresponding to...). Figure 10A (as indicated by arrow 145 in the diagram), while the cable rotates and moves in an axial reciprocating motion. For some applications, the drive cable comprises multiple coaxial coiled layers. For example, as... Figures 10A-10C As shown, the drive cable may include an outer layer 136 and an inner layer 138, which are coaxial with each other, and each layer includes coiled wire.

[0257] Typically, the drive cable is housed within a first outer tube 140, which is configured to remain stationary as the drive cable undergoes rotational and / or axial reciprocating motion. The first outer tube is configured to effectively function as a support tube for the drive cable along its length. Therefore, the first outer tube is also referred to herein as a drive cable support tube. Reference will be made below. Figure 10D The drive cable support tube is described in further detail. For some applications, the drive cable support tube is disposed within a second outer tube 142, which is typically made of a material with greater flexibility than the drive cable support tube (e.g., nylon and / or polyether block amide) and typically has a greater thickness than the drive cable support tube.

[0258] Typically, during insertion of the impeller and frame into the left ventricle, the impeller 50 and frame 34 are held in a radially constrained configuration by the delivery catheter 143. As described above, to allow the impeller and frame to present a non-radially constrained configuration, the delivery catheter is retracted. For some applications, such as Figure 10A As shown, during the operation of the left ventricular device, the delivery catheter remains in the subject's aorta, and the outer tube 142 is positioned inside the delivery catheter. (Although) Figure 10A The distal end of the delivery catheter is shown positioned within the aortic arch, but for some applications, during operation of the left ventricular device, the distal end of the delivery catheter is positioned within the descending aorta. For some applications, during operation of the left ventricular device, a passage 224 is defined between the delivery catheter 143 and the outer catheter 142. (Note that, for illustrative purposes,...) Figure 10A (The channels shown are not to scale.) For some such applications, the subject's aortic blood pressure is measured by measuring the blood pressure within channel 224. For example, pressure sensor 216 (in... Figure 1A (Illustrated schematically) may be in fluid communication with channel 224 and may be configured to measure the subject's aortic pressure by measuring the blood pressure within channel 224. Typically, to retract the left ventricular device from the subject, the delivery catheter is advanced over the impeller and frame such that the impeller and frame exhibit their radially constrained configuration. The catheter is then withdrawn from the subject.

[0259] For some applications, the drive cable 130 consists of multiple coaxial layers, each coaxial layer including multiple coiled wires 134. For example, as... Figures 10A-10CAs shown, the drive cable includes an outer layer 136 and an inner layer 138, each layer comprising a coiled wire. Typically, when the impeller begins to rotate, if the direction of rotation of the impeller causes the rotation of the drive cable in that direction to at least partially tighten the coiled wire of the drive cable, this will also cause the impeller to advance relative to the frame due to the tightening of the coiled wire (i.e., the winding reduces the radius of the coil) and thus axial elongation. For some applications, at least a portion of the drive cable is configured such that (a) in response to the impeller rotating in a predetermined direction of rotation to pump blood from the left ventricle to the aorta, (b) the rotation of the drive cable in that direction causes the coiled wire of the drive cable to at least partially unwind along a portion of the drive cable, causing that portion of the drive cable to axially shorten (e.g., become loose, thereby increasing the radius of the coil). For some applications, the impeller is configured to rotate counterclockwise when viewed from the proximal end to the distal end of the impeller, and the coiled wire in each layer of the drive cable is configured to be placed in the left hand position. When the impeller rotates counterclockwise, the counter-pressure applied to each layer of the drive cable's coils causes them to partially unwind, thereby shortening each layer of the drive cable. Alternatively, the impeller is configured to rotate clockwise when viewed from the proximal end to the distal end of the impeller, and the coils in each layer of the drive cable are configured to be right-handed.

[0260] Refer again Figure 6A and 6B These demonstrate, according to some applications of the invention, the range of axial reciprocating motion of the impeller within the frame 34 during the cardiac cycle. As described above, Figure 6A The impeller is positioned closest to the heart during the cardiac cycle (typically, the impeller is positioned in this order during systole), and Figure 6B This indicates the impeller's furthest position during the cardiac cycle (typically, the impeller is positioned this way during diastole). For example... Figure 6A As shown, for some applications, at the closest position to the impeller, the proximal end of the impeller is positioned at location I. P At that location, I P Within the proximal conical segment of frame 34. (e.g.) Figure 6B As shown, for some applications, at the farthest position of the impeller, the far end of the impeller is set at position Id, which is at the far end of the cylindrical segment of frame 34.

[0261] Refer again Figures 10A-10CReferring to the drive cable configuration described in these figures, typically, by configuring the drive cable as described above, the length of frame 34 does not need to accommodate the distal movement of the impeller caused by the axial elongation of the drive cable due to cable fastening when the impeller and drive cable begin to rotate. Note that for some applications, the drive cable does not shorten because the drive cable support tube 140 limits the extent to which the drive cable can unwind and thus shorten axially (and / or for other reasons). Furthermore, for some applications, although theoretically the drive cable would shorten if the impeller rotated without any fluid, in practice, the drive cable does not shorten when the impeller rotates in the subject's blood flow. This is because when the impeller rotates in the subject's blood flow, the back pressure of the blood pumped by the impeller pushes the impeller distally, thus counteracting the unwinding of the drive cable (which would cause the drive cable to shorten). For some applications, during diastole, the drive cable actually becomes longer relative to the impeller when stationary because the pressure gradient resisted by the impeller pumping increases relative to systole. Typically, even in such applications, at least during contraction, the drive cable is configured not to elongate when stationary relative to the impeller, as the winding of the coil is configured as described above.

[0262] For some applications, in addition to configuring the orientation of the coiled wire within the drive cable as described above, the drive cable is initially held within frame 34 in a preloaded (i.e., pre-tensioned) state, such that the drive cable is stretched even before the drive cable and impeller begin to rotate. That is, even before the drive cable and impeller begin to rotate, the drive cable is stretched relative to its stationary state (i.e., the state of the drive cable without any external force acting on it). For example, the connecting element 65 (in some applications, it extends proximally, as referenced above) Figures 6D-6EThe drive cable can be engaged with the proximal support 116, for example, to hold the drive cable in a preloaded state. Typically, (a) because the orientation of the coiled wire within the drive cable is configured as described above, and / or (b) because the drive cable is held within the frame 34 in a preloaded state, the drive cable will not elongate even during diastole (e.g., even when the impeller is pumped against a pressure gradient of 50-70 mmHg) when the impeller and drive cable begin to rotate. For some applications, the drive cable will not elongate even during diastole until the impeller rotates at a rotational rate exceeding 6,000 RPM or 8,000 RPM. For some applications, by configuring the drive cable in this way, the amount of elongation of the drive cable during the cardiac cycle is limited to less than 5 mm (and typically less than 4 mm) even when the impeller rotates at more than 20,000 RPM. Furthermore, for some applications, by configuring the drive cable in this way, the widest part of the impeller (typically located at the center of the impeller's length) is positioned within the proximal half of the frame 34 for more than 50% of the cardiac cycle duration, even when the impeller is rotating at more than 20,000 RPM.

[0263] For some applications, the ventricular assist device is configured such that, even during diastole, even when the impeller rotates at speeds exceeding 20,000 RPM, there is an axial distance between the impeller position at its maximum diameter and the blood inlet opening. For example, the ventricular assist device is configured such that, during diastole, even when the impeller rotates at speeds exceeding 20,000 RPM, there is an axial distance exceeding 3 mm (e.g., exceeding 5 mm) between the impeller position at its maximum diameter and the blood inlet opening. For some such applications, this reduces hemolysis (compared to a smaller or no axial distance between the impeller position at its maximum diameter and the blood inlet opening) and / or improves impeller efficiency by reducing turbulence, by allowing the blood flow lines entering the blood inlet opening to become at least partially aligned with the longitudinal axis of the impeller before being pumped by the impeller.

[0264] Typically, the outer layer 136 of the drive cable contains fewer coiled wires than the inner layer 138, and each wire is wider than the wires in the inner layer. For example, the ratio of the number of wires in the outer layer to the number of wires in the inner layer can be between 2:3 and 2:5. For some applications, the outer layer contains 4-8 wires, while the inner layer contains 10-14 wires. For some applications, the ratio of the wire diameter in the outer layer to the wire diameter in the inner layer is between 3:2 and 5:2. For some applications, the wire diameter in the outer layer is between 0.15 mm and 0.2 mm, while the wire diameter in the inner layer is between 0.075 mm and 0.125 mm. Typically, the coiled wires in both layers are made of alloy. For some applications, the inner diameter of the drive cable (i.e., the diameter of the cavity 132) is between 0.4 mm and 0.7 mm. More typically, the outer diameter of the drive cable (defined by the outer layer 138) is between 1 mm and 1.2 mm. For some applications, the total length of the drive cable 130 is greater than 1 m (e.g., greater than 1.1 m) and / or less than 1.4 m (e.g., less than 1.3 m), for example, 1-1.4 m or 1.1-1.3 m. Typically, the diameters of cavities 122 and 133 are approximately similar to the diameter of cavity 132.

[0265] For some applications, the drive cable includes a first (distal) portion and a second (proximal) portion. Typically, the first portion is configured to be disposed within the aortic arch of the subject, while the second portion is configured to be disposed along the descending aorta and typically extends to the motor unit 23 outside the subject's body. Typically, at locations where the drive cable 130 undergoes significant bending, such as at the aortic arch, it is desirable that the drive cable be relatively flexible. However, a drive cable with greater flexibility is typically also more capable of axial stretching than a drive cable with less flexibility. Therefore, for some applications, there is a trade-off between wanting the drive cable to be flexible enough to conform to the curvature of the aortic arch, but on the other hand, not wanting the drive cable to undergo significant axial stretching (which could lead to loss of control over the axial position of the impeller). For some applications, the corresponding portions of the drive cable have a corresponding degree of flexibility. For example, the first portion of the drive cable configured to be disposed within the aortic arch may have a first degree of flexibility, while the second portion of the drive cable configured to be disposed within the descending aorta may have a second degree of flexibility, with the first flexibility being greater than the second flexibility.

[0266] For some applications, the distal portion of the drive cable is configured to have greater flexibility than the proximal portion because the coils of wire 134 in the distal portion have different parameters than those used in the proximal portion. For some applications, the distal portion has parameters that are substantially similar to those described above (i.e., regarding the inner and outer layers). For some applications, the proximal portion of the guide wire comprises a single layer of coiled wire. Typically, the number of coiled wires in the proximal portion of the drive cable is less than the number of coiled wires in the outer layer of the distal portion of the drive cable. Typically, the ratio of the number of wires in the outer layer of the distal portion of the drive cable to the number of wires in the proximal portion of the drive cable is between 3:2 and 5:2. For some applications, there are 3 to 6 wires in the proximal portion of the drive cable. Typically, the diameter of the coiled wires in the proximal portion of the drive cable is even larger than the diameter of the coiled wires in the outer layer of the distal portion of the drive cable. For some applications, the ratio of the wire diameter in the proximal portion to the wire diameter in the outer layer of the distal portion is between 3:2 and 5:2. For some applications, the wire diameter in the distal portion of the drive cable is between 0.2 mm and 0.35 mm. Typically, the inner and outer diameters of the distal and proximal portions of the drive cable are similar (or the same), and are typically as described above.

[0267] Now for reference Figure 10D This is a schematic diagram of a first outer tube 140 according to some applications of the invention, which acts as a drive cable support tube. For some applications, the drive cable support tube includes an outer layer 141 and an inner layer 144, each typically made of a biocompatible polymer material, and a coil 153 embedded between the outer and inner layers. For some applications, the outer layer 141 is made of Pebax, the inner layer 144 is made of PTFE and / or polyimide (e.g., a mixture of PTFE and / or polyimide), and the coil is made of an alloy (e.g., stainless steel). Typically, the inner layer comprises a material configured to provide a low level of friction and high abrasion resistance. Furthermore, the outer layer is typically configured to provide additional strength to the drive cable support tube while still providing sufficient flexibility to conform to the curvature of, for example, the aortic arch. Typically, the coil is configured such that the drive cable support tube maintains a substantially circular cross-section even in areas where the drive cable support tube undergoes significant bending (e.g., within the aortic arch). Typically, without coils, the drive cable support tube will tend to be flat and form an elliptical cross-section in these areas.

[0268] Now for reference Figure 11A , Figure 11B , Figure 11C , Figure 11D and Figure 11EThese are schematic diagrams of apparatus and methods for cleaning drive cables 130, radial supports 116, 118 and / or impeller bushings 58 of a ventricular assist device 20 according to some applications of the present invention.

[0269] First, refer to Figure 11A Typically, an axial shaft and a drive cable define a continuous cavity 132 through which it passes. For some applications, the left ventricular assist device is guided to the aorta and left ventricle by placing the axial shaft and cable over the guide wire 10 (as described above), such that the guide wire is positioned within the cavity 132. Typically, the guide wire is inserted through a duckbill valve 390 (or other hemostatic valve) located at the distal end of the distal distal portion of the distal distal element 107. The guide wire passes through the cavity 122 (of the distal distal portion) and then into the cavity 132 defined at that point by the axial shaft. The guide wire then continues through the cavity 132 until the proximal end of the drive cable. The guide wire passes from the proximal end of the drive cable through a cavity 133 defined by a pin 131, which remains outside the subject's body even after the distal end of the ventricular assist device 20 has been inserted into the subject's left ventricle. Typically, when the distal end of the ventricular assist device is positioned inside the left ventricle of the subject, the guide wire is retracted from the subject's body by pulling it out from the proximal end of the cavity 133. Subsequently, the axial position of the driven magnet 82 (with pin 131 disposed therein) is fixed so that it is positioned between the drive magnets 77, as... Figure 7A As shown. For example, a portion of the driven magnet in motor unit 23 can be secured using locking element 150 (such as...). Figure 11B (As shown) A portion of the drive magnet 77 is connected to the motor unit. For some applications, see the following reference. Figures 23A-23C The described technique is used to insert the guide wire into the distal end element 107. For some applications, by using the cavity 132 of the axial shaft and cable in the manner described above, it is not necessary to provide an additional guide wire guide used during insertion of the left ventricular assist device 20.

[0270] For some applications, cavity 132 is additionally cleaned by the ventricular assist device's cleaning system 29 (such as...). Figure 1A (As shown). Typically, both the first outer tube 140 and the second outer tube 142 remain stationary during the rotation of the drive cable. For some applications, the cleaning system 29 is used via inlet port 86 and outlet port 88 (in... Figure 7A-Figure 7Bii , Figure 11B and Figure 11C(As shown) Control the flow of the cleaning fluid (e.g., a fluid containing glucose or dextrose). The fluid is configured to remove air from the space between the drive cable and the outer tube, and / or reduce the friction between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable), and / or reduce the friction between the axial shaft 92 and the proximal support 116 and / or the distal support 118.

[0271] Refer again Figure 11A For some applications, the cleaning fluid is pumped between the first outer tube 140 and the second outer tube 142, and an opening 146 is provided in the first outer tube near the proximal support. For some applications, the cleaning fluid is pumped through a cleaning fluid passage 226 defined between the first and second outer tubes, as described below. Figure 21 Further detailed description. For some applications, the cleaning fluid flows through opening 146 between the first outer tube 140 and the drive cable 130, such as... Figure 11A The cleaning fluid flow is indicated by arrow 148. In this way, the interface between the drive cable 130 (which rotates) and the outer tube 140 (which acts as a drive cable support tube and remains stationary during drive cable rotation) is cleaned. For some applications, some cleaning fluid additionally flows to the interface between the axial shaft and the proximal support 116, thereby cleaning this interface (and / or reducing friction at this interface), such as... Figure 11A The flow of the cleaning fluid is indicated by arrow 149. Typically, the flow of the cleaning fluid in the direction of arrow 149 also prevents blood from flowing into the interface between the axial shaft and the proximal support.

[0272] As mentioned above (see reference) Figures 10A-10C The drive cable typically comprises multiple coiled wires. In some applications, the cleaning fluid enters the cavity 132 defined by the drive cable through gaps in the coiled wires. Once the cleaning fluid is positioned within the cavity 132, it flows in both proximal and distal directions, such as... Figure 11A As shown by arrow 151. Figure 11A As indicated by arrow 152, the cleaning fluid flowing in the distal direction typically exits the distal end of cavity 132 and flows toward cavity 122 defined by the distal end portion. At the end of the distal end portion, a duckbill valve 390 typically prevents the cleaning fluid from flowing out of the distal end portion. Therefore, some of the cleaning fluid typically flows toward the interface between the axial shaft and the distal support 118, thereby cleaning the interface (and / or reducing friction at the interface), such as... Figure 11A The cleaning fluid flow is indicated by arrow 154. Typically, the flow of cleaning fluid in the direction of arrow 154 also prevents blood from flowing into the interface between the axial shaft and the distal support.

[0273] As described above, once the cleaning fluid is placed within the cavity 132, the cleaning fluid flows in both the proximal and distal directions, such as... Figure 11A As shown by arrow 151. Now refer to... Figure 11B Typically, at the proximal end of the ventricular assist device 20, the cleaning fluid flows out of the proximal end of the cavity 132 in the direction of arrow 156, and subsequently out of the proximal end of the cavity 133 defined by pin 131. In some applications, the cleaning fluid then flows in the direction of arrow 157 and around the driven magnet 82 to reduce frictional forces on the driven magnet 82. In some applications, the cleaning fluid then flows out of the outlet port 88 in the direction of arrow 158. Typically, the cleaning fluid is then disposed of. Alternatively, the cleaning fluid is pumped back into the device via the inlet port 86.

[0274] Referring to the above description of the cleaning process typically used for the ventricular assist device 20, it should be noted that cavities 122, 132 and 133 (as described above, which were previously used to facilitate insertion of the device over the guide wire 10) typically serve as flow channels for cleaning fluid during use of the ventricular assist device.

[0275] Now for reference Figure 11C For some applications, the ventricular assist device includes an additional cleaning fluid inlet port 89, typically used to pump cleaning fluid into a channel 224 between the delivery catheter 143 and the outer tubing 142. For some applications, the cleaning fluid is pumped into this channel at a sufficiently low pressure to allow aortic blood pressure to still be detected via this channel, as described elsewhere in this application. For some applications, instead of continuously pumping cleaning fluid into channel 224, fluid is pumped into the channel periodically to flush it. For some applications, port 89 and channel 224 are used for aortic pressure sensing. For example, pressure sensor 216 (which...) Figure 1A (Illustrated in the diagram) can be located within channel 224, within port 89, and / or at different locations in fluid communication with channel 224.

[0276] refer to Figure 11D and Figure 11EFor some applications, the axial shaft 92 includes a cleaning fluid orifice configured to allow cleaning fluid to flow out from the cavity 132 defined by the axial shaft 92. For some applications, the axial shaft defines a cleaning fluid orifice 190 near the distal bushing 58 of the impeller 50. As described above, for some applications, the distal bushing is configured to be slidable relative to the axial shaft. For some such applications, the interface between the distal bushing and the axial shaft is cleaned by the cleaning fluid flowing from the cleaning fluid orifice 190. For some applications, the axial shaft defines an orifice 192 near the distal radial support 118. For some such applications, the interface between the distal radial support and the axial shaft is cleaned by the cleaning fluid flowing from the cleaning fluid orifice 192. For some applications, the axial shaft defines an orifice 194 near the proximal radial support 116. For some such applications, the interface between the distal radial support and the axial shaft is cleaned by the cleaning fluid flowing from the cleaning fluid orifice 194.

[0277] Now for reference Figure 12A and Figure 12B These are schematic diagrams of a ventricular assist device 20, which, according to some applications of the invention, includes a liner 39 that lines the interior of a frame 34 housing an impeller 50. (For illustrative purposes, the liner 39 and pump outlet pipe 24 are shown on the side of the device facing outwards from the page.) Figures 12A-12B (The image shown is transparent.) For some applications, the liner 39 is disposed within the frame 34 to provide a smooth inner surface through which blood is pumped by the impeller. Typically, by providing a smooth surface, the liner material reduces hemolysis caused by impeller-pumped blood compared 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 (PEBAX®).

[0278] Typically, the liner is disposed above at least the inner surface of the columnar portion of the frame 34 (e.g., the columnar portion is on...). Figures 12A-12B (As shown in the diagram). For some applications, the pump outlet pipe 24 also covers the cylindrical portion 38 of the frame 34, for example, around the outside of the frame, such that the pump outlet pipe 24 and the liner 39 overlap for at least 50% of the liner length, for example, over the entire length of the cylindrical portion of the frame 34, such as... Figure 12A As shown. For some applications, there is only partial overlap between the pump outlet pipe 24 and the liner 39, for example, as Figure 12BAs shown. For example, the pump outlet pipe 24 may overlap the liner along less than 50% (e.g., less than 25%) of the liner length. 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 in the overlapping area between the pump outlet pipe and the liner, thus eliminating a longitudinal position where the impeller, pump outlet pipe 24, frame 34, and liner 39 all overlap each other. As described above, refer to Figure 1D 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 multiple lateral blood inlet openings. For some such applications, the columnar portion of the frame is lined with a liner 39.

[0279] Typically, in any overlapping area between the liner 39 and the pump outlet pipe 24, the liner is shaped to form a smooth surface (e.g., to reduce hemolysis, as described above), and the pump outlet pipe 24 is shaped to conform to the struts of the frame 34 (e.g., as shown above). Figure 12A (as shown in the cross-section). Typically, in the overlapping area between the liner 39 and the pump outlet pipe 24, the pump outlet pipe and the liner are joined together, for example, via vacuum, via adhesive and / or using a thermoforming process, as described below.

[0280] For some applications, the liner 39 and the pump outlet pipe 24 are made of different materials. For example, the liner may be made of polyurethane, while the pump outlet pipe may be made of polyether block amide (PEBAX®). Typically, the material used to manufacture the liner has a higher thermoforming temperature than the material used to manufacture the pump outlet pipe. For some applications where the liner and the pump outlet pipe overlap along at least a portion of the frame 34 (e.g., along the columnar portion of the frame 34), the pump outlet pipe and the liner are joined to each other and / or joined to the frame in the following manner: Initially, the liner is placed on a mandrel. Subsequently, the frame is placed on the liner. Subsequently, the pump outlet pipe 24 is positioned around the outside of the frame. For some applications, in order to mold the pump outlet pipe 24 to conform to the pillars of the frame 34 without causing deformation of the liner, the frame is heated to a temperature higher than the thermoforming temperature of the pump outlet pipe 24 but lower than the thermoforming temperature of the liner 39. Typically, the frame is heated from the inside using a mandrel. Typically, when the frame is heated to the aforementioned temperature, the outer tube (typically made of silicone resin) applies pressure to the pump outlet pipe 24, causing the pump outlet pipe 24 to be radially pushed inward so that the pump outlet pipe conforms to the shape of the frame's support, such as... Figure 12A The cross-section is shown. For some applications, the combination of the frame, liner, and the portion of the pump outlet pipe 24 arranged around the frame is then shaped to the desired shape and size using shaping techniques known in the art.

[0281] For some applications (not shown), the density of the frame struts at the distal end of the columnar portion of the frame is greater than the density of the struts in other parts of the columnar portion of the frame. For some such applications, the increased density of the frame struts at the distal end of the columnar portion of the frame facilitates the bonding of the liner and / or pump outlet pipe to the frame. For some applications, the liner and / or pump outlet pipe does not extend all the way to the end of the columnar portion of the frame, for example, as referenced... Figure 13 As described above. For some such applications, at the longitudinal position along the columnar section of the frame, where the liner and / or pump outlet pipe terminates, the density of the frame supports increases relative to other positions along the columnar section of the frame.

[0282] Now for reference Figure 13 This is a schematic diagram of a ventricular assist device 20 according to some applications of the present invention, wherein at least the distal portion 333 of the cylindrical portion 38 of the frame 34 is not covered. For some applications, during the axial reciprocating motion cycle of the impeller, even when the impeller is positioned at its furthest point within the frame 34, the portion of the impeller at its maximum span will not advance beyond a given position within the cylindrical portion of the frame (e.g., as referenced above). Figures 10A-10C (As described above). For some applications, a portion of the frame (which extends distally beyond that location) is not covered by the pump outlet pipe 24 or the liner 39. (Note that for illustrative purposes, the frame is shown without the liner 39. However, for some applications, the frame is lined with the liner 39. Typically, even in such applications, the distal portion 333 of the columnar section of the frame is not covered by the pump outlet pipe 24 or the liner 39.)

[0283] For some applications, the uncovered distal portion of the columnar section of the frame effectively widens the entrance because (e.g.) Figure 13 (As indicated by the blood flow arrows in the diagram) Blood flows into the cylindrical portion of the frame from the side. For some applications, this reduces hemolysis caused by the impeller pumping blood. Optionally or additionally, the diameter of pump portion 27 can be reduced when the pump portion is in its radially constrained configuration by leaving a portion of the cylindrical portion of the frame uncovered. For example, the pump portion can be radially constrained such that the widest portion of the impeller overlaps with the uncovered portion of the cylindrical portion of the frame to reduce the diameter of the pump portion of the ventricular assist device (as opposed to if the widest portion of the impeller overlaps with the covered portion of the cylindrical portion of the frame, such that the widest portion of the impeller overlaps with the frame and the covering material).

[0284] For some applications, ventricular assist devices are configured such that, even during diastole, there is an axial distance between the impeller position at its maximum diameter and the blood inlet opening. For example, a ventricular assist device is configured such that, during diastole, there is an axial distance exceeding 3 mm (e.g., exceeding 5 mm) between the impeller position at its maximum diameter and the blood inlet opening (e.g., as referenced above). Figures 10A-10C (as described above). For some such applications, this reduces hemolysis (relative to a smaller or no axial distance between the impeller position at its maximum diameter and the blood inlet opening) and / or improves impeller efficiency by reducing turbulence, by allowing the blood flow lines entering the blood inlet opening to become at least partially aligned with the longitudinal axis of the impeller before being pumped by the impeller.

[0285] Now for reference Figure 14 This is a schematic diagram (showing a cross-sectional view of the left ventricle) of a ventricular assist device 20 placed within the left ventricle 22 of a subject according to some applications of the present invention. For illustrative purposes, Figure 14 The aortic valve 26 is shown covering a cross-section of the left ventricle, although the aortic valve lies in a different plane than the plane of the main sectional view. Also referenced... Figures 15A-15D These figures are schematic diagrams of the distal end element 107 of a ventricular assist device according to some applications of the invention, which is at least partially curved to define a curvature resembling a question mark, and also refer to... Figure 16A and Figure 16B These figures are arrangements placed in the left ventricle of a subject according to some applications of the present invention. Figures 15C-15D A schematic diagram of a ventricular assist device.

[0286] In some applications, the ventricular assist device is guided by a guide wire, through which it is inserted toward the apex 342 of the left ventricle. The wall of the left ventricle can be considered to consist of a septal wall 338 (which separates the left ventricle from the right ventricle 340), a posterior wall 336 (from which papillary muscles 341 protrude, and the mitral valve device is positioned above the posterior wall 336), and a free wall 334, each of which occupies approximately one-third of the circumference of the left ventricle (e.g., ...). Figure 14(The dashed lines dividing the left ventricle into three equal parts are shown). Typically, it is undesirable for the distal terminal element (or any other part of the ventricular assist device) to contact the diaphragmatic wall, as this could potentially lead to arrhythmias. More typically, it is desirable to maintain a distance between the distal terminal element (and any other part of the ventricular assist device) and the posterior wall so as not to interfere with the mitral valve device and to prevent the mitral valve device from interfering with the function of the ventricular assist device. Therefore, the ventricular assist device is typically guided toward the apex in such a way that if and when the distal terminal element contacts the ventricular wall of the left ventricle, the ventricular assist device contacts the free wall 334, as shown. Figure 14 and Figures 16A-16B As shown.

[0287] Typically, as described above, the ventricular assist device is introduced into the ventricle of a subject via a guideline. The distal distal portion 120 defines a cavity 122 such that the distal distal portion remains in a straight configuration during introduction of the ventricular assist device into the subject's ventricle. For some applications, the distal distal portion is configured to exhibit its curved shape when the guideline is removed. Note that... Figures 15A-15D The shape of the distal distal portion 120 initially formed is shown. Typically, due to the insertion of the guide wire through the cavity 122 (thus temporarily straightening the distal portion), the curvature of the distal distal portion is less than that of the guide wire when deployed into the left ventricle of the subject. Figures 15A-15D The curvature shown in at least some of the examples. For example, Figure 15C The curvature of the distal end portion is shown, causing the curved portion of the distal end portion to form a complete loop. However, Figure 15C The distal end portion in Figure 16A The image shows the left ventricle of the subject, and the distal portion does not form a complete loop.

[0288] As described above, the distal end portion 120 typically forms part of the distal end element 107, which also includes an axial shaft receiving tube 126. Typically, the distal end element 107 is configured such that in its unconstrained configuration (i.e., without any force acting on the distal end portion), the distal end element is at least partially curved. For some applications, in a given plane, the distal end element 107 has a proximal straight portion 346 (at least a portion of which typically includes the axial shaft receiving tube 126). The proximal straight portion of the distal end element 107 defines a longitudinal axis 348. The curved portion of the distal end element 107 bends away from the longitudinal axis 348 in a first direction and then, at an inflection point, bends relative to the longitudinal axis 348 in the opposite direction. For example, as... Figures 15A-15B As shown, within the plane of the paper, the distal end element first bends towards the top of the paper, then towards the bottom, and as... Figures 15C-15DAs shown, within the plane of the paper, the distal end element first bends towards the bottom of the paper and then towards the top. Typically, when shaped as... Figures 15A-15D As shown, the distal end element defines an overall curvature resembling a question mark or a tennis racket, and the distal end element defines a bulge 351 on one side of the longitudinal axis of the flat proximal portion of the distal end element. For some applications, the bulge is generally shaped as a semi-ellipse. (It should be noted that in this case, the term "semi-ellipse" includes a semicircle. It should also be noted that in some cases, the end is not defined as a precise semi-ellipse, but rather as a bulge that is substantially similar to a semi-ellipse.)

[0289] like Figures 15A-15B As shown, for some applications, after the inflection point, the distal end element continues to bend, causing the distal end element to cross back onto the longitudinal axis 348. Figure 15A An example is shown in which the end of the distal end element has not yet crossed back onto the longitudinal axis, and there is a large gap between the distal end of the distal end element and the proximal end of the curved portion. Figure 15B An example is shown where the end of the distal end element crosses back onto the longitudinal axis again, and a small gap exists between the distal end of the distal end element and the proximal end of the curved portion. Figures 15C-15D (These figures are cross-sectional and isometric views of the distal end element of the same shape, respectively.) As shown, for some applications, after the inflection point, the end does not bend so that the distal end element crosses back onto the longitudinal axis 348. Conversely, all the curvature of the bent portion of the distal end element appears on one side of the longitudinal axis 348.

[0290] refer to Figure 15C Typically, a hemostatic valve (e.g., a duckbill valve 390) is disposed within the distal segment of the distal distal portion 120 and configured to prevent blood from flowing into the cavity 122. Typically, the duckbill valve has a maximum width of less than 3 mm, for example, less than 2 mm, and typically the entire duckbill valve is disposed within the distal segment of the distal distal portion, which is located within the distal 10 mm of the distal distal portion, for example, within the distal 5 mm of the distal distal portion. For some applications, the duckbill valve faces proximally (i.e., the wide inlet of the valve faces the distal end of the distal distal portion, and the narrow end of the valve faces away from the distal end of the distal distal portion 120). Typically, when deployed in the left ventricle of a subject, the curvature of the curved portion of the distal distal element 107 is configured to provide a trauma-resistant end to the ventricular assist device 20. More typically, the distal distal element is configured to separate the inlet opening 108 of the ventricular assist device from the wall of the left ventricle.

[0291] Now for reference Figure 16A and Figure 16B First, note that these figures show a cross-sectional view of the left ventricle 22, with the septal wall 338 positioned on the left side of the page and the free wall 334 positioned on the right side. In this view, the left atrium 359 and left atrial appendage 358 are visible above the left ventricle, and the right ventricle 340 is visible to the left of the left ventricle. Note that, as Figures 16A-16B (as well as Figure 17Ai-Figure 17D The view of the aorta and left ventricle shown is different from, for example... Figure 1B The view shown. Figure 1B This is an illustrative illustration provided for purposes of explanation and does not necessarily provide a proper description of the proportions and orientation of ventricular assist devices relative to anatomical structures.

[0292] For some applications, the distal end element 107 is configured to separate the blood inlet opening from the posterior wall of the subject's left ventricle when the distal end element is placed against the apex of the subject's left ventricle. Typically, the distal end element is configured to separate the blood inlet opening from the septal wall of the subject's left ventricle when the distal end element contacts the apex of the subject's left ventricle.

[0293] Typically, the distal end element 107 is inserted into the left ventricle such that the bulge 351 bulges toward the diaphragm wall 338. When configured in this way, in response to the distal end element 107 being pushed toward the apex of the heart (e.g., due to a physician's advance mechanism or in response to movement of the left ventricle), the blood inlet opening 108 is typically pushed toward the free wall 334 and away from the diaphragm wall 338 (in... Figure 16B (In the direction of the arrow shown). Typically, this is due to the proximal straight portion 346 pivoting around the question mark-shaped curved portion, as shown. In contrast, other shaped ends, if arranged in a similar orientation, may cause the blood inlet opening to be pushed toward the septum wall. For example, if the distal end element has a pigtail end (where the end bends along a single curvature direction), and this pigtail end is oriented such that the pigtail bend is on the free wall side of the longitudinal axis of the straight portion of the distal end element, then pushing the end distally will typically cause the blood inlet opening to be toward the septum wall due to the tightening of the pigtail bend loop.

[0294] refer to Figures 14-16B All figures in the invention include the use of a question mark or tennis racket-shaped distal end element in conjunction with any ventricular assist device, even without other features and / or portions of the distal end element 107 (e.g., axial shaft receiving tube 126). It is also noted that, typically, the curvature of the distal end portion lies within a single plane.

[0295] Now for reference Figure 17Ai and Figure 17AiiThese are schematic diagrams of a ventricular assist device 20, which, according to some applications of the invention, has a balloon 220 disposed on its distal end element 107, the balloon being configured to facilitate movement of an axial shaft 92 relative to the wall of the ventricle.

[0296] As described above, typically, the axial shaft 92 passes through the impeller 50 axis via the impeller cavity 62. More typically, the axial shaft is rigid, such as a rigid tube. The axial shaft itself is radially stabilized via a proximal radial support 116 and a distal radial support 118. Furthermore, 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. For some applications, the axial shaft enters the axial shaft receiving tube 126 of the distal end element 107. Typically, if the axial shaft bends, the frictional forces between the axial shaft and the distal and radial supports increase. Therefore, it is typically desirable for the axial shaft to remain in a straight configuration. For some applications, the balloon 220 provides the distal end of the distal end element with respect to the wall of the left ventricle in a manner that does not cause substantial movement of the proximal end of the distal end portion (which defines the axial shaft receiving tube). For example, as Figure 17Ai and Figure 17Aii As indicated by the arrow near the apex 342, the balloon can rotate relative to the apex without causing substantial movement of the axial shaft receiving tube. Therefore, even if the balloon undergoes movement relative to the apex (as from...), Figure 17Ai to Figure 17Aii As shown in the transition), the axial shaft also remains in a substantially straight configuration. For some applications, a cleaning fluid is used, for example, using the fluid specified in US2020 / 0237981 of the Reference Journal. Figure 13 The technique described in D for filling balloon 220, US2020 / 0237981, is incorporated herein by reference.

[0297] Now for reference Figure 17Bi and Figure 17 Bii These are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, which has a connector 230 configured to facilitate pivoting of its distal end portion 120 relative to its axial shaft. As described above, for some applications, the distal end element 107 includes an axial shaft receiving tube 126 and the distal portion 120. For some applications, the connector 230 allows movement of the distal end portion 120 relative to the axial shaft receiving tube 126. For example, the connector 230 may be a ball-and-socket connector as shown, and / or it may be a swivel connector, and / or a universal connector. Thus, even if the distal end portion undergoes movement relative to the apex 342 of the left ventricle (e.g., from... Figure 17Bi to Figure 17Bii As shown in the transition), the axial shaft 92 also remains in a substantially straight configuration. For some such applications, the distal end portion 120 is shaped as described above.

[0298] Now for reference Figure 17C The diagram shows a ventricular assist device according to some applications of the invention, wherein the outer tubes 140 and / or 142 are shaped with a predetermined curvature such that when the axial shaft is positioned within the left ventricle 22 of the subject, the axial shaft 92 of the ventricular assist device remains in a substantially straight configuration.

[0299] As referenced above Figures 10A-10C In some applications, the drive cable 130 is disposed within a first outer tube 140, which is configured to act as a drive cable support tube, remaining stationary when the drive cable undergoes rotational and / or axial reciprocating motion. The first outer tube is configured to effectively act as a support along the length of the drive cable. In some applications, the first outer tube 140 is disposed within a second outer tube 142. In some applications, at least one of the first and second outer tubes is shaped such that the portion of the outer tube disposed within the aortic arch has a predetermined radius of curvature RC, which is greater than 18 mm and / or less than 32 mm (e.g., less than 24 mm), for example, 18-32 mm or 18-24 mm. In some applications, by defining such a radius of curvature, the axial shaft enters the left ventricle at an angle such that when the distal end portion of the ventricular assist device is positioned near the apex 342, the axial shaft is in a substantially straight configuration.

[0300] Now for reference Figure 17D This is a schematic diagram of a ventricular assist device 20 according to some applications of the invention, having a distal end 240 configured to anchor to the tissue at the apex 342 of the left ventricle. In some applications, the distal end 240 is a screw-shaped element (e.g., a screw-tapered element as shown), and is configured to screw into the tissue at the apex to anchor the distal end of the ventricular assist device to the apex. Typically, anchoring the distal end to the apex reduces movement of the pump portion 27 relative to the internal structures of the left ventricle, and thereby reduces the risk of damage to the internal structures of the left ventricle that may result from such movement.

[0301] Now for reference Figure 18A , Figure 18B and Figure 18C These figures are schematic diagrams of the distal radial support 118 of a ventricular assist device according to a corresponding application of the present invention.

[0302] refer to Figure 18AFor some applications, radial supports are disposed within support housing 119. In some such applications, the radial supports and support housing are made of corresponding, different materials. For example, the radial supports may be made of a first material with relatively high hardness (e.g., ceramic), and the support housing may be made of a second material that is relatively easy to form into the desired shape, such as a metal or alloy (e.g., stainless steel, cobalt-chromium, and / or nickel-titanium). For some applications, a proximal radial support 116 is also disposed within the support housing, wherein the proximal radial supports and support housing are made of corresponding, different materials (generally similar to the manner described with reference to the distal radial support 118). As described above, for some applications, the ventricular assist device includes a distal extension 121 configured to reinforce the region of the distal end element (the distal end of the shaft 92 moves into this region) (e.g., the axial shaft receiving tube 126 or a portion thereof, described below). For applications where the distal radial support 118 is disposed within the support housing 119, the distal extension 121 typically includes an extension extending from the support housing 119 rather than from the distal radial support itself. As described above, typically at the distal end of the frame 34, the distal strut joint 33 is placed into a groove defined by the outer surface of the distal radial support 118, the groove being shaped to conform to the shape of the distal strut portion. For some applications, the outer surface of the support housing (rather than the outer surface of the support) is shaped to define such a groove (the groove being formed by...). Figure 18A and Figure 18B (Reference number 127 in the text is indicated).

[0303] Now for reference Figure 18B For some applications, a material layer 123 is disposed between the radial support 118 and the support housing 119. In some applications, this material is configured to allow some movement of the radial support relative to the support housing and / or cushion such movement. For example, the material layer may comprise an elastomeric material layer. For some applications, the proximal radial support 116 has a similar configuration, wherein a material (e.g., an elastomeric material) is disposed between the radial support and the support housing, and this material is configured to allow some movement of the radial support relative to the support housing and / or cushion such movement. For some such applications, by allowing movement between the radial support and the support housing, the material layer allows some movement of the rigid axial shaft relative to the frame 34. In some applications, in this way, the axial shaft 92 is allowed to become slightly misaligned with the longitudinal axis of the frame.

[0304] refer to Figure 18CFor some applications, the outer surface 125 of the distal radial support 118, which abuts the inner surface of the support housing 119, has a convex curve. For some applications, the convex, curved outer surface of the support is configured to allow some movement of the radial support relative to the support housing. For some applications (not shown), the inner radial surface of the support housing (which abuts the outer surface of the support) has a convex curve, for example, allowing some movement of the radial support relative to the support housing. For some applications, the proximal radial support 116 has a similar configuration, wherein the outer surface of the support and / or the inner radial surface of the support housing has a convex curve. For some such applications, the aforementioned shapes of the support and / or the support housing allow movement of a rigid axial shaft relative to the frame 34 by allowing movement between the radial support and the support housing. For some applications, in this way, the axial shaft is allowed to become slightly misaligned with the longitudinal axis of the frame.

[0305] For some applications, the length of the radial support allows the rigid axial shaft to move relative to the frame 34, such that the axial shaft is allowed to be slightly misaligned with the longitudinal axis of the frame. For example, the length of each of the proximal and distal radial supports may be less than 2 mm, less than 1.5 mm, or less than 1 mm, for example, 0-1.5 mm or 0.5-1 mm.

[0306] Now for reference Figure 19A This is a schematic diagram of a ventricular assist device 20 according to some applications of the present invention, wherein the pump outlet pipe 24 is configured to bend as blood is pumped through the pump outlet pipe, and the pump outlet pipe is rotatable relative to the distal end portion 120 of the ventricular assist device. Also refer to... Figure 19B This is according to some applications of the invention in the absence of other components of a ventricular assist device. Figure 19A A schematic diagram of the pump outlet pipe 24. Also refer to... Figure 19C It is disposed within the aorta 30 and left ventricle 22 of the subject according to some applications of the present invention. Figures 19A-19B A schematic diagram of the ventricular assist device 20. Note that, as shown... Figure 19C The views of the aorta and left ventricle shown are different from, for example... Figure 1B The view shown. Figure 1B These are illustrative diagrams provided for purposes of explanation and do not necessarily represent an accurate depiction of the proportions and orientation of ventricular assist devices relative to anatomical structures. It should also be noted that... Figure 19C The views of the aorta and left ventricle shown are different from, for example... Figures 16A-16B and Figure 17Ai-Figure 17D The view shown. Figure 19C A cross-sectional view of the left ventricle is shown, with the posterior wall 336 positioned on the left side of the page and the free wall 334 positioned on the right side of the page.

[0307] As described above, for some applications, the frame 34 is not disposed within the tube along the proximal portion of the pump outlet tube 24, and therefore the tube is not supported by the frame 34 in the open position. The tube 24 is typically made of a collapsible material that is impermeable to blood. For example, the tube 24 may comprise polyurethane, polyester, and / or silicone. Alternatively or additionally, the tube may be made of polyethylene terephthalate (PET) and / or polyether block amide (PEBAX®). Typically, the proximal portion of the tube is configured to be positioned such that it is at least partially disposed within the subject's ascending aorta. For some applications, the proximal portion of the tube passes through the subject's aortic valve, entering the subject's ascending aorta from the subject's left ventricle, such as... Figure 1B As shown. As described above, the tube typically defines one or more blood inlet openings 108 at its distal end, through which blood flows from the left ventricle into the tube during impeller operation. For some applications, the proximal portion of the tube defines one or more blood outlet openings 109, through which blood flows from the tube into the ascending aorta during impeller operation. During impeller operation, the blood flow pressure through the tube typically keeps the proximal portion of the tube open.

[0308] For some applications, the pump outlet tube 24 is pre-formed such that the tube is curved during impeller operation when the blood flow pressure through the tube keeps the proximal portion of the tube open. Typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the posterior wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. Furthermore, more typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the diaphragmatic wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. For some applications, the curvature of the tube maintains the spacing between the blood inlet opening 108 and the posterior wall 336 of the left ventricle, the mitral valve leaflet 402, and / or the subvalvular portion of the mitral valve (e.g., chordae tendineae 404, cardiac column, and / or papillary muscle 341), such as... Figure 19C As shown.

[0309] Typically, tube 24 is pre-formed using a blow molding die in a bending die, or pre-formed using a molding die after a blow molding or dip molding process. Typically, the distal portion of the tube (where the frame 34, impeller 50, and axial shaft 92 are disposed) is held in a flat and open configuration by the frame 34. The portion of the tube located proximal to the frame 34 and within the left ventricle is typically shaped to define the aforementioned curvature. For some applications, this curvature results in an angle gamma between the longitudinal axis of the tube at its proximal end and the longitudinal axis of the tube at its distal end being greater than 90 degrees (e.g., greater than 120 degrees, or greater than 140 degrees), and / or less than 180 degrees (e.g., less than 160 degrees, or less than 150 degrees), for example, 90-180 degrees, 90-160 degrees, 120-160 degrees, or 140-150 degrees. For some applications, the curvature of the tube is such that the surface of the tube located inside the bend defines a radius of curvature R, which is greater than 10 mm, for example greater than 20 mm, and / or less than 200 mm (e.g., 100 mm), for example 10 mm–200 mm, or 20 mm–100 mm. (In Figure 19B The image shows a dashed circle with a dashed line spanning its diameter, indicating the method of measuring the radius of curvature R.

[0310] Note, as referenced Figures 19A-19C The pump outlet pipe 24 is configured such that (a) in the absence of blood flow through the pipe, the pipe typically collapses in response to a pressure on the outside of the pipe exceeding the pressure on the inside, and (b) when blood flows through the pipe at a sufficient rate, such that the pressure inside the pipe exceeds the pressure on the outside, the pipe assumes its pre-formed curved configuration. It should also be noted that when the pipe 24 assumes its curved configuration, the pipe typically causes the portion of the drive cable 130 disposed within the curved portion of the pipe to also become curved, such as... Figure 19A and Figure 19C As shown. That is, it is the preforming of the tube itself that typically causes the tube and drive cable to bend, rather than the drive cable (or different components disposed within the tube) causing the tube to bend. Alternatively, the outer tubes 140 and / or 142 (which are disposed around the drive cable) are shaped to define the bend, and the outer tubes cause the drive cable and tube 24 to take on a bent shape. For some applications, both the outer tubes 140 and / or 142 and tube 24 are shaped to define the bend shape.

[0311] Now for reference Figures 19D-19E These figures are schematic diagrams of a ventricular assist device 20 according to some applications of the invention, wherein the pump outlet pipe 24 is configured to bend as blood is pumped through the pipe. Figure 19D and Figure 19E In the illustration, tube 24 is shown without other components of the ventricular assist device (e.g., impeller 50, frame 34, etc.). Figure 19EAccording to some applications of the present invention, the aorta 30 and left ventricle 22 of the subject are disposed therein. Figure 19D A schematic diagram of the ventricular assist device 20. Figure 19E The view of the left ventricle shown is similar to Figure 19C The view shown. For some applications, the inlet opening 108 and / or outlet opening 109 are configured in a non-axisymmetric manner around the tube 24. Typically, the tube 24 defines the positions of the inlet opening and / or outlet opening such that the tube 24 becomes curved and / or remains as shown in the reference. Figures 19A-19C The curvature of the tube 24. For example, as shown, the blood inlet orifice can be located on the side of the tube 24 located inside the bend of the tube (or on the side of the desired bend of the tube). As blood flows into the blood inlet orifice, this reduces the pressure in the region above the blood inlet orifice, and the distal end of the tube 24 is pulled toward that region (as indicated by arrow 310). Alternatively or additionally, the blood outlet orifice 109 can be located on the side of the tube 24 located inside the bend of the tube (or on the side of the desired bend of the tube). As blood flows out of the blood outlet orifice, the blood impacts the aortic wall, which causes the proximal end of the tube 24 to be pushed in the opposite direction (i.e., in the direction of arrow 312).

[0312] For reference Figures 19A-19C As stated, typically, such as Figure 19E As shown, the curvature of the pump outlet tube maintains the space between the blood inlet opening 108 and the posterior wall 336 of the left ventricle, the mitral valve leaflet 402, and / or the subvalvular portion of the mitral valve (e.g., chordae tendineae 404, cardiac column, and / or papillary muscle 341). Typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the posterior wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. Furthermore, more typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the septal wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall.

[0313] For some applications, when deploying a ventricular assist device into the left ventricle, the distal terminal portion is deployed first. As described above, the distal terminal portion is typically deployed relative to the left ventricular anatomy in a given orientation. Typically, the pump outlet tubing is deployed after the distal terminal portion is deployed. In some cases, the distal terminal portion has already been deployed relative to the left ventricular anatomy in the desired orientation, but a curved portion of the tubing is not positioned in the left ventricle in the desired orientation. Therefore, for some applications, the distal terminal portion is deployed via connector 212 (which allows the pump outlet tubing to rotate relative to the distal terminal portion of the ventricular assist device, such as...) Figures 19A-19E(As indicated by arrow 210) It is connected to the pump outlet pipe (directly or indirectly). For example, the joint can be a rotary joint and / or a ball joint (e.g., as shown by arrow 210). Figure 17Bi-Figure 17Bii The ball joint 230 shown), and / or universal joint (e.g., such as...) Figures 20A-20C (See connector 232). For some applications, the connector is located within the proximal portion of the distal end element 107. Optionally or additionally, the connector is located between the distal end portion 120 and the axial shaft receiving tube 126 (e.g., as shown). Figure 17Bi-Figure 17Bii (As shown).

[0314] Now for reference Figure 19F This is a schematic diagram of a ventricular assist device 20 according to some applications of the present invention, which includes a bending element 218 configured to provide a predetermined curvature to a tube 24. For some applications, the tube 24 itself is shaped to define a bend (e.g., as shown in reference...). Figures 19A-19E As an alternative to or supplement to the aforementioned ventricular assist device, the ventricular assist device includes a bending element 218. Typically, the bending element is made of a shape memory material, such as a shape memory alloy like nitinol. For some applications, the bending element is formed from a nitinol tube that is cut to define holes or slots, allowing the tube to be pre-shaped into the desired bending shape. For example, the nitinol element may be a nitinol "hypo tube" (i.e., a nitinol tube with micro-engineered features along its length) known in the art. Typically, the bending element 218 is positioned around the drive cable 130 along a longitudinal segment of the drive cable proximal to (e.g., directly proximal to) the proximal radial support 116. For some applications, along this longitudinal segment of the drive cable, the bending element is used in place of the outer tube 142.

[0315] For some applications, bending elements are shaped to have a curvature that is approximately similar to a reference. Figures 19A-19E The curvature is relative to that described for tube 24. For some applications, the curvature is such that the angle between the longitudinal axis of the bending element at its proximal end and the longitudinal axis of the bending element at its distal end is greater than 90 degrees (e.g., greater than 120 degrees, or greater than 140 degrees), and / or less than 180 degrees (e.g., less than 160 degrees, or less than 150 degrees), for example, 90-180 degrees, 90-160 degrees, 120-160 degrees, or 140-150 degrees. For some applications, the curvature of the tube is such that the radius of curvature defined by the surface of the bending element located inside the bend is greater than 10 mm, for example, greater than 20 mm, and / or less than 200 mm (e.g., 100 mm), for example, 10 mm-200 mm, or 20 mm-100 mm. See reference... Figures 19A-19CTypically, the curvature of the tube maintains the septum between the blood inlet 108 and the posterior wall 336 of the left ventricle, the mitral valve leaflet 402, and / or the subvalvular portion of the mitral valve (e.g., chordae tendineae 404, cardiac column, and / or papillary muscles 341), as... Figure 19C As shown. Typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the posterior wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. Furthermore, more typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the septal wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall.

[0316] For some applications, when deploying a ventricular assist device in the left ventricle, the distal terminal portion is deployed first. As described above, the distal terminal portion is typically deployed relative to the left ventricular anatomy in a given orientation. Typically, after deploying the distal terminal portion, the bending element 218 is deployed. In some cases, the distal terminal portion has already been deployed relative to the left ventricular anatomy in the desired orientation, and the bending element 218 is not positioned in the left ventricle in the desired orientation. Therefore, for some applications, the distal portion is deployed via connector 212 (which allows the pump outlet tubing to rotate relative to the distal terminal portion of the ventricular assist device, such as...) Figures 19A-19E (As indicated by arrow 210) It is connected directly or indirectly to the bending element 218. For example, the joint can be a swivel joint and / or a ball joint (e.g., as shown by arrow 210). Figure 17Bi-Figure 17Bii The ball joint 230 shown), and / or universal joint (e.g., such as...) Figures 20A-20C (See connector 232). For some applications, the connector is located within the proximal portion of the distal end element 107. Optionally or additionally, the connector is located between the distal end portion 120 and the axial shaft receiving tube 126 (e.g., as shown). Figure 17Bi-Figure 17Bii (As shown).

[0317] refer to Figures 19A-19F Note that for some applications, because the outer tube 142 is anchored to the aorta and the distal portion 120 becomes anchored to the left ventricular wall (e.g., the free wall near the apex), the tube 24 adopts a curved shape, as described above. It should also be noted that... Figures 16A-16B The curvature of the tube shown is less than Figures 19A-19F The curvature of the tube shown is because Figures 16A-16B Different views of the device are shown. Figures 16A-16B In the view shown, the curvature is typically less than Figures 19A-19F The view shown is clear.

[0318] Now for reference Figures 20A-20CThese are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, wherein the axial shaft 92 of the device includes a connector 232 (e.g., a universal joint as shown). As shown, the connector is typically disposed within a portion of the axial shaft, configured to be located between the proximal bushing 64 and the distal bushing 58 of the impeller. Note that in Figure 20A In the illustration, several parts of the impeller (e.g., the membrane 56 and spring 54 of the material) are not shown for illustrative purposes, and to provide visibility of this part of the axial shaft, which is typically disposed between the proximal bushing 64 and the distal bushing 58 of the impeller, within a cavity 62 defined by the impeller (e.g., cavity 62 in...). Figures 3A-3C (As shown in the diagram). Alternatively, the connector may be positioned at different locations along the axial shaft, such as near the impeller or far from the impeller.

[0319] For some applications, connector 232 is disposed between the proximal portion 234 and the distal portion 236 of the axial shaft, which are connected to each other by the connector, allowing the proximal and distal portions to bend relative to each other. Typically, the connector allows the axial shaft to take a shape consistent with the curvature of other parts of the left ventricular device and / or the anatomy of the subject. For some applications, the connector is configured to allow the axial shaft to conform to the curvature of the frame 34, such that even if the frame 34 becomes slightly bent, the proximal portion of the axial shaft is coaxially disposed relative to the proximal support 116, and the distal portion of the axial shaft is coaxially disposed relative to the distal support 118.

[0320] Figure 21 This is a schematic diagram of a ventricular assist device including one or more blood pressure measuring tubes 222 according to some applications of the invention. As described above, typically, the ventricular assist device includes a pump outlet tube 24 passing through the aortic valve of a subject, such that the proximal end of the tube is disposed within the subject's aorta, while the distal end of the tube is disposed within the subject's left ventricle. Typically, a blood pump (which typically includes an impeller 50) is disposed within the tube 24, within the subject's left ventricle, and is configured to pump blood from the left ventricle into the subject's aorta through the tube 24. For some applications, the ventricular blood pressure measuring tube 222 is configured to extend at least to the outer surface 213 of the tube 24, such that an opening 214 at the distal end of the blood pressure measuring tube is in direct fluid communication with the patient's blood flow outside the tube 24. Typically, the opening 214 is configured within the subject's left ventricle, proximal to the blood pump (e.g., proximal to the impeller 50). Pressure sensor 216 (in Figure 1A(Illustrated schematically) Measuring blood pressure within the ventricular blood pressure measuring tube. Typically, the pressure sensor measures the subject's blood pressure (i.e., left ventricular blood pressure) outside the tube 24 by measuring the blood pressure within the left ventricular blood pressure measuring tube. Typically, the blood pressure measuring tube 222 extends from outside the subject to an opening 214 at the distal end of the tube, and the pressure sensor 216 is positioned toward the proximal end of the tube, for example, outside the subject's body. For some applications, a computer processor 25 ( Figure 1A It receives the measured blood pressure reading and controls the blood pumping performed by the impeller in response to the measured blood pressure.

[0321] For some applications, ventricular assist devices include two or more such ventricular blood pressure measuring tubes 222, for example, such as Figure 21 The ventricular blood pressure measuring tube 222 is shown in the diagram. For some applications, based on the blood pressure measured in each of the two or more ventricular blood pressure measuring tubes, the computer processor 25 determines whether the opening of one of the two or more ventricular blood pressure measuring tubes is blocked. This could, for example, occur due to the opening coming into contact with the ventricular septum wall and / or different ventricular portions. Typically, in response to the determination that the opening of one of the two or more ventricular blood pressure measuring tubes is blocked, the computer processor determines the subject's left ventricular pressure based on the blood pressure measured in another of the two or more ventricular blood pressure measuring tubes.

[0322] For some applications, the outer tube 142 defines a groove 215 in a portion of the outer surface of the outer tube that is configured to be disposed within the tube 24. Typically, during insertion of the ventricular assist device into a subject, a portion of the ventricular blood pressure measuring tube 222 extending from within the tube 24 to at least the outer surface of the tube 24 is configured to be disposed within the groove, such that this portion of the ventricular blood pressure measuring tube does not protrude from the outer surface of the outer tube.

[0323] For some applications (not shown), the distal portion of the blood pressure measuring tube 222 is disposed outside the pump outlet tube 24. For example, the blood pressure measuring tube 222 may extend from the outer tube 142 to the proximal end of the pump outlet tube 24, after which the blood pressure measuring tube may be embedded in the outer surface of the pump outlet tube 24, for example, as shown in Figure 16D of US 10,881,770 of Tuval, which is incorporated herein by reference.

[0324] As described above, for some applications, the drive cable 130 extends from a motor outside the subject's body to an axial shaft 92 disposed on the impeller 50. Typically, the drive cable is housed within the first outer tube 140 and the second outer tube 142, as described above. For some applications, the proximal portion of the blood pressure measuring tube 222 includes a channel between the first outer tube 140 and the second outer tube 142, such as... Figure 21The cross-section is shown. In this regard, it should be noted that the blood pressure measuring tube should be understood as a continuous cavity extending from the pressure sensor 216 to the outside of the pump outlet tube 24 within the left ventricle of the subject, regardless of any structural changes along the length of the cavity. As mentioned above, a cleaning fluid is typically pumped between the outer tubes 140 and 142, and for some applications, the cleaning fluid is pumped through channel 226. Typically, the blood pressure measuring tube 222 occupies a larger cross-sectional area defined between the outer tubes 140 and 142 than the cleaning fluid channel 226, such as Figure 21 As shown. For example, the ratio of (a) the cross-sectional area occupied by the blood pressure measuring tube defined between outer tubes 140 and 142 to (b) the cross-sectional area occupied by the cleaning fluid channel 226 defined between outer tubes 140 and 142 is typically greater than 3:2, greater than 3:1, or greater than 5:1. For some applications, the blood pump measuring tube occupies a relatively large proportion of the cross-sectional area defined between outer tubes 140 and 142 in order to transmit blood pressure outside the pump outlet tube 24 in the left ventricle of the subject proximally to the pressure sensor 216.

[0325] Now for reference Figure 22A and Figure 22B These are schematic diagrams of a sterile sleeve 242 according to some applications of the invention, configured to form a seal between the delivery catheter 143 and the outer tube 142 of the ventricular assist device 20. For some applications (not shown), the delivery catheter 143 is inserted into an artery (e.g., the femoral or radial artery) of the subject via an inserter sheath (not shown), the inserter sheath being inserted into an incision in the artery and typically remaining in place within the artery throughout operation of the ventricular assist device. For such applications, the sterile sleeve (generally similar to...) Figures 22A-22B The sleeve shown is typically positioned between the delivery catheter 143 and the infeeder sheath (not shown) to allow movement between the delivery catheter and the infeeder sheath while maintaining the sterility of the arterial incision.

[0326] For some alternative applications, the ventricular assist device (VAD) is initially inserted through an arterial incision via a delivery sheath, which is then removed during the remainder of the VAD procedure. For example, the VAD can be inserted via a peel-off delivery sheath. The delivery catheter is then typically placed in direct contact with the arterial incision. Typically, this reduces the diameter of the device positioned within the arterial incision for the remainder of the procedure, compared to a scenario where the delivery sheath remains within the incision throughout the entire VAD procedure. For example, the outer diameter of the delivery catheter might be less than 3.3 mm (i.e., 10 French), and this is the diameter through the incision once the delivery sheath has been removed. The inner diameter of the delivery catheter is typically less than 3 mm (i.e., 9 French), for example, it could be 2.7 mm (i.e., 8 French). Conversely, if the delivery sheath remains in place throughout the VAD procedure, this increases the diameter through the incision because the thickness of the sheath wall must be accommodated by the incision. For example, it could increase the diameter by 0.3–0.6 mm (i.e., approximately 1–2 French).

[0327] In some such applications, the delivery catheter is advanced until its distal end is positioned at a given location within the subject's aorta (e.g., within the ascending aorta). Subsequently, the pump portion 27 of the ventricular assist device is advanced relative to the distal end of the delivery catheter by advancing the outer tube 142 relative to the delivery catheter. In such applications, a sterile sleeve 242 forms a seal between the delivery catheter 143 and the outer tube 142 of the ventricular assist device 20, allowing movement of the outer tube relative to the delivery catheter while maintaining the sterility of the arterial incision. In some such applications, the ventricular assist device is provided to the user in the form of a kit containing a sterile sleeve 242 positioned appropriately between the outer tube 142 and the delivery catheter 143.

[0328] Now for reference Figures 23A-23C This is a schematic diagram of a distal straightening element 270 according to some applications of the invention, which is used to straighten the distal distal portion 120 of the ventricular assist device 20 during insertion of the guide wire 10 through the distal distal portion 120 of the ventricular assist device 20. As described above, typically, the ventricular assist device is inserted into the subject's ventricle via the guide wire 10, the ventricular assist device being arranged in a radially constrained (i.e., coiled) configuration in the delivery catheter 143 (e.g., as shown in the diagram). Figure 1B(Illustrated schematically) Typically, the guide wire is first inserted into the ventricular assist device at the distal end of the distal terminal element 107. For some applications, to facilitate the insertion of the guide wire through the distal end of the distal terminal element (i.e., through the distal terminal portion 120), a terminal straightening element 270 is positioned around the distal terminal element, for example, to hold the distal terminal element in a straightened configuration. Typically, the straightening element is a housing defining a flat cavity 271. The straightening element is positioned around the distal terminal element such that the distal terminal element is configured in a straightened configuration within the cavity 271, and the guide wire is inserted into the distal end of the distal terminal element (i.e., through the distal portion 120), for example, as... Figure 23B As shown. For some applications, the straightening element is configured to be removable from the distal end element, while the guide wire is disposed in the distal end element. For example, the straightening element may be notched, perforated, and / or have a slit 272 (as shown) extending along its length to facilitate removal of the straightening element from the distal end element, for example, as... Figure 23C As shown.

[0329] Now for reference Figure 24A , Figure 24B and Figure 24C These are graphs illustrating measurements performed during the use of a left ventricular assist device according to some applications of the invention. The left ventricular assist device described herein is deployed within the heart of a pig. The pig's arterial pulsation is measured using an intra-aortic pressure sensor while the left ventricular assist device operates at a corresponding rotational rate. The device is calibrated based on in vitro tests performed on it to determine the flow rate produced when the impeller rotates at the corresponding rate. Figure 24A The graph shows the arterial pulsation versus flow rate generated by the device, measured in experiments conducted on pigs (using a predetermined correspondence between impeller rotation rate and flow rate). Then... Figure 24A The points shown in the figure are fitted to a curve, and this curve is extrapolated to the y-intercept (i.e., when the arterial pulsation is zero), as shown. Figure 24B As shown in the figure, by extrapolating the curve, the flow rate at zero arterial pulsation was estimated to be 5.6 L / min. In the same pig, cardiac output was measured using a Swan-Ganz catheter when the left ventricular assist device was inactive. The Swan-Ganz catheter measured the pig's natural cardiac output at 5.2 L / min, which is similar to the flow rate estimated by extrapolating the flow rate / arterial pulsation curve at zero arterial pulsation. It is assumed that at zero arterial pulsation, the left ventricular assist device largely replaces the heart's inherent function, and that at this value, the flow rate produced by the pump provides a reasonable approximation of the subject's natural cardiac output.

[0330] Based on the above experimental results, for some applications of the present invention, during the operation of the ventricular assist device, the subject's arterial pulsation is measured, and parameters are derived from the subject's arterial pulsation. Typically, as the impeller rotational speed increases, the flow rate generated by the blood pump increases. Typically, the flow rate generated by the blood pump is non-pulsatile because the blood pump is a continuous flow blood pump rather than a pulsatile blood pump. Therefore, typically, as the impeller rotational speed and the flow rate generated by the blood pump increase, the subject's arterial pulsation decreases. In some applications, the subject's arterial pulsation is measured as the impeller rotational speed changes. Based on the above measurements, the relationship between arterial pulsation and impeller rotational speed and / or pump flow rate is derived. In some applications, based on the above relationship, the subject's natural cardiac output can be derived. For some such applications, when the subject's arterial pulsation reaches zero, the relationship between the subject's arterial pulsation and pump flow rate is extrapolated to determine what the pump flow rate would be. Based on the above results, it is assumed that at this value, the pump is replacing the heart's inherent function, and the flow rate generated by the pump at this value provides an approximation of the subject's natural cardiac output.

[0331] Regarding references Figures 1A-24C All aspects of the described ventricular assist device 20 should be noted, although Figure 1A and Figure 1B A ventricular assist device 20 is shown in the left ventricle of a subject; however, for some applications, device 20 is placed in the right ventricle of the subject, such that the device (with necessary modifications) passes through the subject's pulmonary valve, and the techniques described herein are applied. For some applications, components of device 20 are adapted to different types of blood pumps. For example, aspects of the invention can be applied to pumps 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 tube 24 (e.g., tube curvature), impeller 50, features of pump portion 27, drive cable 130, etc. Alternatively or additionally, device 20 and / or a portion thereof (e.g., impeller 50, even without tube 24) are placed within different parts of the subject's body to assist in pumping blood from those parts. For example, device 20 and / or a portion thereof (e.g., impeller 50, even without 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 a portion thereof (e.g., impeller 50, even without tube 24) (with necessary modifications) are configured for placement within the subclavian or jugular vein, at the junction of the vein and lymphatic vessels, and for increasing the flow rate of lymphatic fluid from the lymphatic vessels into the vein. Because the scope of the invention includes the use of the devices and methods described herein in 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.

[0332] The scope of this invention includes combining any device and method described herein with any device and method described in one or more of the following applications, all of which are incorporated herein by reference:

[0333] Tuval filed US 2020 / 0237981, dated January 23, 2020, entitled "Distal tip element for a Ventricular assist device," which claims the following priority:

[0334] Tuval filed U.S. provisional patent application 62 / 796,138 entitled “Ventricular assist device” on January 24, 2019;

[0335] Tuval filed U.S. Provisional Patent Application No. 62 / 851,716 on May 23, 2019, entitled “Ventricular assist device”.

[0336] Tuval's U.S. Provisional Patent Application No. 62 / 870,821, entitled "Ventricular assist device," filed July 5, 2019; and

[0337] Tuval filed U.S. Provisional Patent Application No. 62 / 896,026 on September 5, 2019, entitled “Ventricular assist device”.

[0338] Tuval's US 10,881,770, a continuation application to Tuval's international application PCT / IB2019 / 050186 (published as WO19 / 138350) entitled "Ventricular assist device," filed January 10, 2019, claims the following priority:

[0339] Sohn filed U.S. Provisional Patent Application No. 62 / 615,538 entitled “Ventricular assist device” on January 10, 2018;

[0340] Sohn filed U.S. provisional patent application 62 / 665,718 entitled “Ventricular assist device” on May 2, 2018;

[0341] Tuval's U.S. Provisional Patent Application No. 62 / 681,868, filed June 7, 2018, entitled "Ventricular assist device"; and

[0342] Tuval filed U.S. Provisional Patent Application No. 62 / 727,605 on September 6, 2018, entitled “Ventricular assist device”;

[0343] Tuval's US 2019 / 0269840 is the U.S. national phase of Tuval's international patent application PCT / IL2017 / 051273 (published as WO18 / 096531) entitled "Bloodpumps," filed November 21, 2017, which claims priority to Tuval's U.S. provisional patent application 62 / 425,814, filed November 23, 2016.

[0344] Tuval's US 2019 / 0175806 is a continuation application of Tuval's international application PCT / IL2017 / 051158 (published as WO18 / 078615) entitled "Ventricular assist device" filed on October 23, 2017. This international application claims priority to Tuval's US 62 / 412,631 filed on October 25, 2016 and US 62 / 543,540 filed on August 10, 2017.

[0345] Tuval's US 2019 / 0239998 is the U.S. national phase of Tuval's international patent application PCT / IL2017 / 051092 (published as WO18 / 061002), filed on September 28, 2017, entitled "Bloodvessel tube," which claims priority to Tuval's U.S. provisional patent application 62 / 401,403, filed on September 29, 2016.

[0346] Schwammenthal's US 2018 / 0169313 is the U.S. national phase of Schwammenthal's international patent application PCT / IL2016 / 050525 (published as WO16 / 185473) entitled "Blood pump," filed on May 18, 2016. This international patent application claims priority to Schwammenthal's U.S. provisional patent application 62 / 162,881 entitled "Blood pump," filed on May 18, 2015.

[0347] Schwammenthal's US 10,583,231 is the U.S. national phase of its international patent application PCT / IL2015 / 050532 (published as WO15 / 177793) entitled "Blood pump," filed May 19, 2015. This international patent application claims priority to Schwammenthal's U.S. provisional patent application 62 / 000,192 entitled "Blood pump," filed May 19, 2014.

[0348] Schwammenthal's U.S. Patent 10,039,874 is the U.S. national phase of Schwammenthal's international patent application PCT / IL2014 / 050289 (published as WO14 / 141284), filed March 13, 2014, entitled "Renal pump," which claims priority to (a) Schwammenthal's U.S. Provisional Patent Application 61 / 779,803, filed March 13, 2013, entitled "Kidney pump," and (b) Schwammenthal's U.S. Provisional Patent Application 61 / 914,475, filed December 11, 2013, entitled "Renal pump."

[0349] U.S. Patent 9,764,113, entitled "Curved catheter," was granted to Tuval on September 19, 2017, claiming priority from Tuval's U.S. Provisional Patent Application 61 / 914,470, also entitled "Curved catheter," filed on December 11, 2013; and

[0350] Tuval's US 9,597,205 is the U.S. national phase of its international patent application PCT / IL2013 / 050495 (published as WO13 / 183060) entitled "Prosthetic renal valve," filed June 6, 2013. This international patent application claims priority to Tuval's U.S. provisional patent application 61 / 656,244 entitled "Prosthetic renal valve," filed June 6, 2012.

[0351] Those skilled in the art will recognize that the present invention is not limited to what has been specifically shown and described above. Rather, the scope of protection of the present invention includes both combinations and sub-combinations of the various features described above, as well as variations and modifications of the invention that will arise in the mind of those skilled in the art upon reading the foregoing description and are not found in the prior art.

Claims

1. A method comprising: manufacturing an impeller by: forming a structure having a first bushing and a second bushing at a proximal end and a distal end of the structure, the first and second bushings connected to each other by at least one elongated element; radially expanding the at least one elongated element and forming at least one helical elongated element at least in part by axially compressing the structure; coating the at least one helical elongated element with a coupling agent configured to enhance bonding between the helical elongated element and an elastomer layer; subsequently, coating the coupling agent-coated helical elongated element with the elastomer layer; and subsequently, coupling an elastomer film to the at least one helical elongated element such that the at least one helical elongated element with the elastomer film coupled thereto defines a blade of the impeller.

2. The method of claim 1, wherein, Coupling the elastomer film to the at least one helical elongated element such that the at least one helical elongated element with the elastomer film coupled thereto defines a blade of the impeller includes immersing the helical elongated element in an elastomer material from which the elastomer film is made.

3. The method of claim 1, wherein, The elastomer film includes an elastomeric material having an ultimate elongation exceeding 300%.

4. The method of claim 2, wherein, The elastomer film includes an elastomeric material having an ultimate elongation exceeding 300%.

5. The method of any one of claims 1-4, wherein, The elastomer film includes an elastomeric material having a melt flow index of at least 4.

6. The method of any one of claims 1-4, wherein, The elastomer film includes an elastomeric material having an ultimate tensile strength greater than 6000 psi.

7. The method of claim 5, wherein, The elastomer film includes an elastomeric material having an ultimate tensile strength greater than 6000 psi.

8. The method of any one of claims 1-4 and 7, wherein, Coating the at least one helical elongated element with the coupling agent includes coating the at least one helical elongated element with a silane compound containing a first functional group configured to bond with the helical elongated element and a second functional group configured to bond with the elastomer layer.

9. The method of claim 5, wherein, Coating the at least one helical elongated element with the coupling agent includes coating the at least one helical elongated element with a silane compound containing a first functional group configured to bond with the helical elongated element and a second functional group configured to bond with the elastomer layer.

10. The method of claim 6, wherein, Coating the at least one helical elongated element with the coupling agent includes coating the at least one helical elongated element with a silane compound containing a first functional group configured to bond with the helical elongated element and a second functional group configured to bond with the elastomer layer.

11. The method of any one of claims 1-4, 7, and 9-10, wherein, The elastomer layer is made of a given elastomeric material, and wherein the elastomer film is made of the given elastomeric material.

12. The method of claim 5, wherein, The elastomer layer is made of a given elastomeric material, and wherein the elastomer film is made of the given elastomeric material.

13. The method of claim 6, wherein, The elastomer layer is made of a given elastomeric material, and wherein the elastomer film is made of the given elastomeric material.

14. The method of claim 8, wherein, The elastomeric layer is made of a given elastomeric material, and wherein the elastomeric film is made of the given elastomeric material.

15. The method of any one of claims 1-4, 7, and 9-10, wherein, The elastomeric layer is made of a first elastomeric material, and wherein the elastomeric film is made of a second elastomeric material different from the first elastomeric material.

16. The method of claim 5, wherein, The elastomeric layer is made of a first elastomeric material, and wherein the elastomeric film is made of a second elastomeric material different from the first elastomeric material.

17. The method of claim 6, wherein, The elastomeric layer is made of a first elastomeric material, and wherein the elastomeric film is made of a second elastomeric material different from the first elastomeric material.

18. The method of claim 8, wherein, The elastomeric layer is made of a first elastomeric material, and wherein the elastomeric film is made of a second elastomeric material different from the first elastomeric material.

19. The method of any one of claims 1-4, 7, 9-10, 12-14, and 16-18, wherein, The elastomeric layer is made of a first elastomeric material, and wherein the elastomeric film is made of a second elastomeric material different from the first elastomeric material.

20. The method of claim 5, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

21. The method of claim 6, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

22. The method of claim 8, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

23. The method of claim 11, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

24. The method of claim 15, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

25. The method of any one of claims 1-4, 7, 9-10, 12-14, 16-18, and 20-24, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

26. The method of claim 5, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes spraying elastomer onto the coupling agent-coated helical elongated element.

27. The method of claim 6, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element.

28. The method of claim 8, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element.

29. The method of claim 11, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element.

30. The method of claim 15, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element.

31. The method of claim 19, wherein, Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element. Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element. Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element. Coating the coupling agent-coated helical elongated element with the elastomeric layer includes at least partially rounding the coupling agent-coated helical elongated element.

32. The method of any one of claims 1-4, 7, 9-10, 12-14, 16-18, 20-24, and 26-31, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

33. The method of claim 5, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

34. The method of claim 6, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

35. The method of claim 8, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

36. The method of claim 11, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

37. The method of claim 15, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

38. The method of claim 19, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

39. The method of claim 25, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

40. The method of claim 32, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer includes coating the coupling agent coated helical elongated element with the elastomeric layer within a given time period of coating the at least one helical elongated element with the coupling agent.

41. The method of any one of claims 33-39, wherein, Coating the coupling agent coated helical elongated element with the elastomeric layer further includes spraying additional elastomeric material onto the coupling agent coated helical elongated element after coating the coupling agent coated helical elongated element with the elastomeric layer within the given time period of coating the at least one helical elongated element with the coupling agent. Coating the coupling agent coated helical elongated element with the elastomeric layer further includes spraying additional elastomeric material onto the coupling agent coated helical elongated element after coating the coupling agent coated helical elongated element with the elastomeric layer within the given time period of coating the at least one helical elongated element with the coupling agent.

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