Ventricle assistance device

Abstract

To provide a device and a method in which a blood pump in the body of a subject includes an impeller including proximal and distal bushings, and a frame disposed around the impeller having a proximal bearing and a distal bearing.SOLUTION: An axial direction shaft (92) passes through a proximal bearing and a distal bearing (116 and 118) of a frame (34) and a proximal and distal bushings (64 and 58) of an impeller. The impeller defines the composition that it is restrained in a radial direction and the composition that it is not restrained. The impeller is introduced into the body of a subject in the composition in which it is restrained in a radial direction, and the impeller pumps blood into the body of the subject in the composition in which it is not restrained in the radial direction. The impeller changes from the composition in which it is restrained in the radial direction to the composition in which it is not restrained when the distal bushing slides on the axial direction shaft.SELECTED DRAWING: Figure 5A

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority from the following: U.S. Provisional Patent Application No. 62 / 615,538 by Sohn, entitled "Ventricular assist device", filed on January 10, 2018; U.S. Provisional Patent Application No. 62 / 665,718 by Sohn, entitled "Ventricular assist device", filed on May 2, 2018; U.S. Provisional Patent Application No. 62 / 681,868 by Tuval, entitled "Ventricular assist device", filed on June 7, 2018; and, U.S. Provisional Patent Application No. 62 / 727,605 by Tuval, entitled "Ventricular assist device", filed on September 6, 2018.

[0002] All of the applications referenced above are hereby incorporated by reference into this specification. Some applications of the present invention generally relate to medical devices. Specifically, some applications of the present invention relate to ventricular assist devices and methods of using the same.

Background Art

[0003] A ventricular assist device is a mechanical circulatory support device designed to assist and unload the heart chambers in order to maintain or increase cardiac output. They are used in patients suffering from heart failure and also in patients at risk of deterioration of cardiac function during percutaneous coronary intervention. Most commonly, left ventricular assist devices are applied to a defective heart to assist left ventricular function. In some cases, right ventricular assist devices are used to assist right ventricular function. Such assist devices are designed to be either permanently implanted or mounted on a catheter for temporary placement.

Summary of the Invention

Means for Solving the Problems

[0004] According to some applications of the present invention, the ventricular assist device includes an impeller disposed on an axial shaft, and the frame is disposed around the impeller. The ventricular assist device typically includes a tube that crosses the subject's aortic valve, with the proximal end of the tube disposed within the subject's aorta and the distal end of the tube disposed within the subject's left ventricle. The impeller, axial shaft, and frame are disposed within the distal portion of the tube inside the subject's left ventricle. Typically, the impeller is configured to pump blood from the left ventricle into the aorta by rotating. The tube typically defines one or more blood inlet openings at the distal end of the tube, and through the one or more blood inlet openings, blood flows from the left ventricle into the tube during operation of the impeller. For some applications, the proximal portion of the tube defines one or more blood outlet openings, and through the one or more blood outlet openings, blood flows from the tube into the ascending aorta during operation of the impeller.

[0005] For some applications, the impeller includes a proximal bushing and a distal bushing, and the frame includes a proximal bearing and a distal bearing. The axial shaft typically passes through the proximal and distal bearings of the frame, as well as the proximal and distal bushings of the impeller. For some applications, (a) the proximal bushing of the impeller is connected to an axial shaft such that the proximal bushing is held in a position fixed axially relative to the axial shaft, and (b) the distal bushing of the impeller is not connected to the axial shaft such that the distal bushing is not held in a position fixed axially relative to the axial shaft. Typically, the impeller defines a radially constrained configuration and a non-radially constrained configuration, in the radially constrained configuration, the impeller is introduced into the subject's body, and in the non-radially constrained configuration, the impeller is configured to pump blood into the subject's body. For some applications, the impeller changes from its radially constrained configuration to its non-radially constrained configuration by the distal bushing sliding over the axial shaft.

[0006] Typically, the axial shaft is not held in a position fixed axially relative to the proximal bearing and the distal bearing. More typically, the ventricular assist device (and / or its blood pump portion) does not include any thrust bearings configured to be disposed within the subject's body. For some applications, the ventricular assist device includes one or more thrust bearings disposed outside the subject's body, and counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the subject's body.

[0007] For some applications, the motor drives an impeller to pump blood from the left ventricle to the aorta by rotating the impeller, and the impeller is configured to experience axial movement relative to the frame in response to a change in the pressure difference between the left ventricle and the aorta. For some applications, a computer processor measures an indication of the axial movement of the impeller. For some applications, the computer processor derives the cardiac cycle of the subject, the pressure difference between the left ventricle and the aorta, and / or the left ventricular pressure of the subject based on the measured indication of the axial movement of the impeller. For some applications, the computer processor changes the rotational speed of the impeller based at least in part on a sensor signal. For example, the computer processor can determine the left ventricular pressure of the subject based at least in part on the sensor signal and can change the rotational speed of the impeller based at least in part on the determined left ventricular pressure. For some applications, the computer processor reduces the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. For some applications, the impeller is coupled to a magnet such that axial movement of the impeller causes the magnet to experience axial movement, and the computer processor measures an indication of the axial movement of the impeller by measuring the magnetic flux generated by the magnet.

[0008] Typically, the drive cable extends from outside the subject's body to the axial shaft and is configured to impart rotational motion from the motor to the impeller by rotating, such that the impeller pumps blood from the left ventricle to the aorta by rotating in a given direction. For some applications, at least a portion of the drive cable includes a plurality of wires arranged in a coiled configuration, and the coiled configuration is such that, in response to the drive cable rotating in a given direction of rotation, the plurality of wires arranged in the coiled configuration at least partially unwind and a portion of the drive cable shortens axially. For some applications, an outer tube is disposed around the drive cable and the frictional force between the outer tube and the drive cable is typically such as to generate debris. Alternatively or additionally, a fluid (e.g., a purging fluid) is disposed between the outer tube and the drive cable. For some such applications, at least a portion of the drive cable is configured such that the plurality of wires arranged in the coiled configuration is configured to pump debris and / or fluid towards the proximal end of the drive cable.

[0009] For some applications, the drive cable includes a first portion configured to be disposed at least partially within the aortic arch of the subject and a second portion configured to be disposed at least partially within the descending aorta of the subject, and the flexibility of the first portion is greater than the flexibility of the second portion. For example, the first portion of the drive cable can include a first number of wires disposed in a coiled configuration, and the second portion of the drive cable can include a second number of wires disposed in a coiled configuration, and the first number is less than the second number. For example, the first portion of the drive cable can include between 4 and 8 wires disposed in a coiled configuration, and the second portion of the drive cable can include between 8 and 12 wires disposed in a coiled configuration.

[0010] For some applications, the impeller includes at least one helical elongated element (and typically three helical elongated elements) and a spring, and the spring is disposed inside the helical elongated element along the axis around which the helical elongated element is wound. Typically, a film of material (such as silicone) is supported between the helical elongated element and the spring. For some applications, at least one elongated element (such as a string or wire) extends from the spring to the helical elongated element and is configured to maintain the helical elongated element within a given distance from the spring.

[0011] As described above, for some applications, the frame is disposed around the impeller. For some applications, the ventricular assist device includes a stator that includes a plurality of curved protrusions coupled to the proximal end of the frame. Typically, the curvature of the curved protrusion opposes the direction of rotation of the impeller. For some applications, the curvature of the curved protrusion is such that from the distal end of the curved protrusion to the proximal end of the curved protrusion, the curved protrusion gradually becomes closer so as to be parallel to the longitudinal axis of the frame. Typically, the curved protrusion includes a plurality of curved struts integral with the frame and a flexible material (e.g., silicone) extending from the curved strut. For some applications, the flexible material is shaped to define a lumen therethrough.

[0012] As described above, typically, the impeller is disposed within a tube (which may be referred to herein as a "blood pressure pump tube") that extends from the left ventricle of the subject into the aorta of the subject. For some applications, at least one blood pressure measurement tube (which defines an opening at its distal end) extends at least to the outer surface of the blood pressure pump tube such that the opening at the distal end of the blood pressure measurement tube is in direct fluid communication with the blood flow of the subject outside the blood pressure pump tube. A pressure sensor measures the pressure of the blood within the blood pressure measurement tube. For some applications, the blood pressure measurement tube is configured to pass along the outer surface of the blood pressure pump tube from the proximal end of the blood pressure pump tube to the opening at the distal end of the blood pressure measurement tube. Typically, the blood pressure measurement tube is a left ventricular blood pressure measurement tube, and the left ventricular blood pressure measurement tube is configured to extend to the outer surface of the blood pressure pump tube at a location along the blood pressure pump tube that is configured to be within the left ventricle of the subject proximal to the impeller, and the pressure sensor is configured to measure the left ventricular pressure of the subject by measuring the pressure of the blood within the left ventricular blood pressure measurement tube.

[0013] Typically, a blood pressure pump tube defines one or more blood inlet openings in a distal portion of the blood pressure pump tube and one or more blood outlet openings in a proximal portion of the blood pressure pump tube. For some applications, the ventricular assist device includes a radially expandable non-invasive distal tip portion configured to be disposed within the left ventricle of the subject distal to the one or more blood inlet openings. The distal tip portion is typically configured to be inserted into the left ventricle in a radially constrained configuration and to assume a non-radially constrained configuration within the left ventricle of the subject, in which non-radially constrained configuration at least the radially expandable portion of the distal tip portion is radially expanded relative to the radially constrained configuration of the distal tip portion. Typically, in its non-radially constrained configuration, the radially expandable portion of the distal tip portion separates the one or more blood inlet openings from the inner structures of the left ventricle, such as the ventricular septum, chordae tendineae, papillary muscles, and / or the apex of the left ventricle. More typically, in its non-radially constrained configuration, the radially expandable portion of the distal tip portion three-dimensionally separates the one or more blood inlet openings from the inner structures of the left ventricle. For some applications, in its non-radially constrained configuration, the radially expandable portion of the distal tip portion directs blood flow from the left ventricle into the one or more blood inlet openings.

[0014] For some applications, in the radially constrained configuration of the distal tip portion, the distal region of the distal tip portion is configured to be at least semi-rigid and is shaped to converge radially along the longitudinal direction toward the distal end of the distal tip portion. Typically, the ventricular assist device is configured to be inserted into the subject's body through a puncture site in the subject's body. For some applications, during insertion of the ventricular assist device, the distal region of the distal tip portion is configured to act as a dilator by expanding the puncture site.

[0015] Generally, in the specification of this application and in the claims, when the terms "proximal" and related terms are used in relation to a device or a part thereof, they should be construed to mean the end of the device or the part thereof that is typically closer to the location through which the device is inserted into the subject's body when inserted into the subject's body. When the terms "distal" and related terms are used in relation to a device or a part thereof, they should be construed to mean the end of the device or the part thereof that is typically farther from the location through which the device is inserted into the subject's body when inserted into the subject's body.

[0016] The scope of the present invention includes using the devices and methods described herein in anatomical locations other than the left ventricle and the aorta. Thus, a ventricular assist device and / or a part thereof may be referred to herein (in the specification and claims) as a blood pump.

[0017] Thus, according to some applications of the present invention, an apparatus comprising a blood pump configured to be installed inside the subject's body, the blood pump comprising an impeller including proximal and distal bushings, a frame configured to be disposed around the impeller, the frame including a proximal bearing and a distal bearing, an axial shaft configured to pass through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller and the proximal bushing of the impeller is connected to the axial shaft and is configured to be held in a position fixed axially with respect to the axial shaft, The distal bushing of the impeller is not connected to the axial shaft, such that the distal bushing is not held in a position fixed axially relative to the axial shaft. The impeller defines a radially constrained configuration and a non-radially constrained configuration. In the radially constrained configuration, the impeller is introduced into the body of the subject, and in the non-radially constrained configuration, the impeller is configured to pump blood into the body of the subject. The impeller is configured to change from its radially constrained configuration to its non-radially constrained configuration by the distal bushing sliding over the axial shaft. An apparatus is provided.

[0018] In some applications, the impeller is configured to be placed inside the left ventricle of the subject and is also configured to pump blood from the left ventricle of the subject to the aorta of the subject. In some applications, the impeller is configured to be placed inside the right ventricle of the subject and is also configured to pump blood from the right ventricle of the subject to the pulmonary artery of the subject. In some applications, the impeller is configured to be placed inside a blood vessel of the subject. In some applications, the impeller is configured to be placed inside a heart cavity of the subject.

[0019] In some applications, the impeller at least one helical elongate element extending from the proximal bushing to the distal bushing, and a spring disposed along an axis around which the helical elongate element is wound, inside the helical elongate element, and a film of material supported between the helical elongate element and the spring, and At least one flexible elongate element, the at least one flexible elongate element extending from a spring to a helical elongate element and configured to maintain the helical elongate element within a given distance from the spring, the at least one flexible elongate element being selected from the group consisting of strings and wires, and comprising.

[0020] In some applications, the device further comprises a delivery catheter, the delivery catheter being configured to maintain the impeller in a radially constrained configuration during introduction of the impeller into the subject's body, when the impeller is released from the delivery catheter, the impeller is configured to self-expand, thereby causing the distal bushing to slide proximally over the axial shaft and the impeller to assume a radially unconstrained configuration, and to retract the impeller from the subject's body, the distal end of the delivery catheter and the impeller are moved relative to each other such that the distal end of the delivery catheter causes the distal bushing to slide distally over the axial shaft, whereby the delivery catheter is configured to cause the impeller to assume a radially constrained configuration.

[0021] According to some applications of the present invention, a device, the device comprising a ventricular assist device, the ventricular assist device comprising an impeller configured to be disposed inside the left ventricle of a subject, a frame configured to be disposed around the impeller, a motor configured to drive the impeller to pump blood from the left ventricle of the subject to the aorta by rotating the impeller, and comprising, An apparatus is further provided, wherein the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the left ventricle and the aorta.

[0022] In some applications, the impeller includes proximal and distal bushings, the frame includes proximal and distal bearings, the ventricular assist device further includes an axial shaft configured to pass through the proximal and distal bearings defined by the frame and the proximal and distal bushings of the impeller, the axial shaft is connected to at least one of the proximal and distal bushings of the impeller, and at least one bushing is held in a position axially fixed relative to the axial shaft, the axial shaft is not held in a position axially fixed relative to the proximal and distal bearings.

[0023] In some applications, the ventricular assist device does not include any thrust bearings configured to be disposed within the body of the subject. In some applications, the ventricular assist device further includes one or more thrust bearings configured to be disposed outside the body of the subject, and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject.

[0024] In some applications, the motor is configured to drive the impeller to pump blood from the left ventricle of the subject to the aorta of the subject by rotating the impeller in a given direction of rotation, the ventricular assist device includes an axial shaft, and the impeller is disposed on the axial shaft. A drive cable configured to extend from the outside of the subject's body to the axial shaft, the drive cable being configured to impart rotational movement from a motor to an impeller by rotating, and at least a portion of the drive cable including a plurality of wires arranged in a coiled configuration, the coiled configuration being such that in response to the drive cable rotating in a given direction of rotation, the plurality of wires arranged in the coiled configuration are at least partially unwound and a portion of the drive cable shortens axially, the drive cable and further includes.

[0025] In some applications, the device a sensor configured to detect an indication of the axial movement of the impeller and to generate a sensor signal in response thereto, the sensor and a computer processor configured to receive the sensor signal and to generate an output in response thereto, the computer proce ssor and further includes.

[0026] In some applications, the computer processor is configured to generate an output indicative of the subject's cardiac cycle in response to receiving the sensor signal. In some applications, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal. In some applications, the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal.

[0027] In some applications, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal, configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure.

[0028] In some applications, the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased.

[0029] In some applications, the device a magnet, wherein the impeller is coupled to the magnet and axial movement of the impeller causes the magnet to experience axial movement, a sensor configured to detect the magnetic flux generated by the magnet and configured to generate a sensor signal in response thereto, a computer processor configured to receive the sensor signal and configured to generate an output in response thereto further comprising.

[0030] In some applications, the computer processor is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. In some applications, the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. In some applications, the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal.

[0031] In some applications, the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure.

[0032] In some applications, the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased.

[0033] In some applications, the impeller includes proximal and distal bushings, the frame includes proximal and distal bearings, the ventricular assist device further includes an axial shaft configured to pass through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller, the impeller is connected to the axial shaft such that the impeller causes the axial shaft to experience axial forward and backward movement with respect to the proximal and distal bearings of the frame.

[0034] In some applications, the axial shaft is configured to clean the interface between the axial shaft and the proximal and distal bearings of the frame by experiencing axial forward and backward movement with respect to the proximal and distal bearings of the frame. In some applications, the axial shaft is configured to reduce heat generation at the interface between the axial shaft and the proximal and distal bearings of the frame by experiencing axial forward and backward movement with respect to the proximal and distal bearings of the frame, as opposed to the case where the axial shaft does not experience axial forward and backward movement with respect to the proximal and distal bearings of the frame.

[0035] According to some applications of the present invention, an apparatus, the apparatus comprising a blood pump, the blood pump comprising an impeller including proximal and distal bushings, the impeller being configured to pump blood through the body of the subject, the impeller, A frame configured to be disposed around an impeller, the frame including a proximal bearing and a distal bearing, and a proximal bearing and a distal bearing of the frame, and an axial shaft configured to pass through a proximal bushing and a distal bushing of the impeller and including the axial shaft is connected to at least one of the proximal bushing and the distal bushing of the impeller, and at least one bushing is held in an axially fixed position relative to the axial shaft, the axial shaft is not held in an axially fixed position relative to the proximal bearing and the distal bearing, and a device is further provided.

[0036] In some applications, the blood pump does not include any thrust bearings configured to be disposed within the body of the subject. In some applications, the blood pump further includes one or more thrust bearings configured to be disposed outside the body of the subject, and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject.

[0037] In some applications, the device further includes a sensor configured to detect an indication of axial movement of the impeller and to generate a sensor signal in response thereto, and a computer processor configured to receive the sensor signal and to generate an output in response thereto. and further including

[0038] In some applications, a computer processor is configured to generate an output indicative of a subject's cardiac cycle in response to receiving a sensor signal. In some applications, a computer processor is configured to determine a subject's left ventricular pressure based at least in part on the sensor signal. In some applications, a computer processor is configured to vary the rotational speed of an impeller based at least in part on the sensor signal. In some applications, a computer processor is configured to determine a subject's left ventricular pressure based at least in part on the sensor signal and to vary the rotational speed of an impeller based at least in part on the determined left ventricular pressure.

[0039] In some applications, a computer processor is configured to determine a subject's left ventricular pressure based at least in part on the sensor signal, and is configured to vary the rotational speed of an impeller based at least in part on the determined left ventricular pressure.

[0040] In some applications, a computer processor is configured to reduce the rotational speed of an impeller in response to determining that the subject's left ventricular pressure has decreased.

[0041] In some applications, the apparatus includes a magnet to which the impeller is coupled such that axial movement of the impeller causes the magnet to experience axial movement, a sensor configured to detect a magnetic flux generated by the magnet and to generate a sensor signal in response thereto, and a computer processor configured to receive the sensor signal and to generate an output in response thereto. a sensor configured to detect a magnetic flux generated by the magnet and to generate a sensor signal in response thereto, and a computer processor configured to receive the sensor signal and to generate an output in response thereto. and further includes

[0042] In some application examples, the computer processor is configured to generate an output indicating the subject's cardiac cycle in response to receiving a sensor signal. In some application examples, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal. In some application examples, the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal.

[0043] In some application examples, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal, and is configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure.

[0044] In some application examples, the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the subject's left ventricular pressure has decreased.

[0045] In some application examples, the impeller is configured to pump blood from a first location within the subject's body to a second location within the subject's body, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the first location and the second location. In some application examples, the impeller is configured to pump blood from the subject's left ventricle to the subject's aorta, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the left ventricle and the aorta. In some application examples, the impeller is configured to pump blood from the subject's right ventricle to the subject's pulmonary artery, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right ventricle and the pulmonary artery. In some application examples, the impeller is configured to pump blood from the subject's right ventricle to the subject's pulmonary artery, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right ventricle and the pulmonary artery. configured to experience axial forward and backward movement with respect to. In some applications, the impeller is configured to pump blood from the right atrium of the subject to the right ventricle of the subject, and the impeller is configured to experience axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the right atrium and the right ventricle. In some applications, the impeller is configured to pump blood from the large vein of the subject to the right ventricle of the subject, and the impeller is configured to experience axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the large vein and the right ventricle. In some applications, the impeller is configured to pump blood from the right atrium of the subject to the pulmonary artery of the subject, and the impeller is configured to experience axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the right atrium and the pulmonary artery. In some applications, the impeller is configured to pump blood from the large vein of the subject to the pulmonary artery of the subject, and the impeller is configured to experience axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the large vein and the pulmonary artery.

[0046] In some applications, the device a motor configured to drive the impeller to pump blood through the subject's body by rotating the impeller in a given direction of rotation, a drive cable configured to extend from outside the subject's body to the axial shaft, the drive cable being configured to impart rotational movement from the motor to the impeller by rotating, at least a portion of the drive cable including a plurality of wires arranged in a coiled configuration, the coiled configuration being such that in response to the drive cable rotating in a given direction of rotation, the plurality of wires arranged in the coiled configuration are at least partially wound back and a portion of the drive cable is shortened axially, the drive cable further includes.

[0047] In some applications, the impeller is connected to an axial shaft such that the impeller causes the axial shaft to experience axial forward and backward movement relative to the proximal and distal bearings of the frame. In some applications, the axial shaft is configured to clean the interface between the axial shaft and the proximal and distal bearings of the frame by experiencing axial forward and backward movement relative to the proximal and distal bearings of the frame. In some applications, the axial shaft is configured to reduce heat generation at the interface between the axial shaft and the proximal and distal bearings of the frame by experiencing axial forward and backward movement relative to the proximal and distal bearings of the frame, as opposed to the case where the axial shaft does not experience axial forward and backward movement relative to the proximal and distal bearings of the frame.

[0048] According to some applications of the present invention, an apparatus, the apparatus includes a blood pump, the blood pump includes an impeller configured to be disposed inside the body of a subject and configured to pump blood through the body of the subject, and a frame configured to be disposed around the impeller and further provided is an apparatus, wherein the blood pump does not include any thrust bearings configured to be disposed inside the body of the subject.

[0049] In some applications, the blood pump further includes one or more thrust bearings configured to be disposed outside the body of the subject, and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject.

[0050] In some applications, the apparatus A sensor configured to detect an indication of axial movement of an impeller and to generate a sensor signal in response thereto, and A computer processor configured to receive the sensor signal and to generate an output in response thereto, and further comprising.

[0051] In some applications, the computer processor is configured to generate an output indicative of the subject's cardiac cycle in response to receiving the sensor signal. In some applications, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal. In some applications, the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal.

[0052] In some applications, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal, and configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure.

[0053] In some applications, the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the subject's left ventricular pressure has decreased.

[0054] In some applications, the apparatus is a magnet, wherein the impeller is coupled to the magnet and axial movement of the impeller causes the magnet to experience axial movement, and A sensor configured to detect a magnetic flux generated by a magnet and further configured to generate a sensor signal in response thereto, and a computer processor configured to receive the sensor signal and further configured to generate an output in response thereto, and further includes.

[0055] In some applications, the computer processor is configured to generate an output indicative of the subject's cardiac cycle in response to receiving the sensor signal. In some applications, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal. In some applications, the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal.

[0056] In some applications, the computer processor is configured to determine the subject's left ventricular pressure based at least in part on the sensor signal and configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure. In some applications, the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the subject's left ventricular pressure has decreased.

[0057]

[0058] ​In some applications, the impeller is configured to pump blood from a first location within the subject's body to a second location within the subject's body, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the first location and the second location. In some applications, the impeller is configured to pump blood from the left ventricle of the subject to the aorta of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the left ventricle and the aorta. In some applications, the impeller is configured to pump blood from the right ventricle of the subject to the pulmonary artery of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right ventricle and the pulmonary artery. In some applications, the impeller is configured to pump blood from the right atrium of the subject to the right ventricle of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right atrium and the right ventricle. In some applications, the impeller is configured to pump blood from the vena cava of the subject to the right ventricle of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the vena cava and the right ventricle. In some applications, the impeller is configured to pump blood from the right atrium of the subject to the pulmonary artery of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right atrium and the pulmonary artery. In some applications, the impeller is configured to pump blood from the vena cava of the subject to the pulmonary artery of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the vena cava and the pulmonary artery.

[0059] In some applications, the device is A motor configured to drive an impeller to pump blood through a subject's body by rotating the impeller in a given direction of rotation, An axial shaft, wherein the impeller is connected to the axial shaft, A drive cable configured to extend from outside the subject's body to the axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating, at least a portion of the drive cable including a plurality of wires arranged in a coiled configuration, the coiled configuration being such that in response to the drive cable rotating in a given direction of rotation, the plurality of wires arranged in the coiled configuration are at least partially unwound and a portion of the drive cable is shortened axially, and further comprising.

[0060] In some applications, the impeller includes a proximal bushing and a distal bushing, the frame includes a proximal bearing and a distal bearing, the device further includes an axial shaft, the axial shaft passes through the proximal bearing and the distal bearing defined by the frame, and the proximal bushing and the distal bushing of the impeller, the axial shaft is connected to at least one of the proximal bushing and the distal bushing of the impeller, and at least one bushing is held in a position fixed axially with respect to the axial shaft, the axial shaft is not held in a position fixed axially with respect to the proximal bearing and the distal bearing, such that the impeller causes the axial shaft to experience an axial forward and backward movement with respect to the proximal bearing and the distal bearing of the frame.

[0061] In some applications, the axial shaft is configured to clean the interface between the axial shaft and the proximal and distal bearings of the frame by experiencing axial forward and backward movement relative to the proximal and distal bearings of the frame. In some applications, the axial shaft is configured to reduce heat generation at the interface between the axial shaft and the proximal and distal bearings of the frame by experiencing axial forward and backward movement relative to the proximal and distal bearings of the frame, as opposed to the case where the axial shaft does not experience axial forward and backward movement relative to the proximal and distal bearings of the frame.

[0062] According to some applications of the present invention, the following inventive concepts are further provided. Inventive Concept 1. An apparatus, the apparatus comprising: an impeller, wherein the impeller comprises at least one helical elongated element, a spring disposed along an axis around which the helical elongated element is wound inside the helical elongated element, a film of material supported between the helical elongated element and the spring, and at least one flexible elongated element that extends from the spring to the helical elongated element and is configured to maintain the helical elongated element at a given distance from the spring, the at least one flexible elongated element being selected from the group consisting of strings and wires. The apparatus comprising the above.

[0063] Inventive Concept 2. The apparatus according to Inventive Concept 1, wherein the impeller is configured such that the outer diameter of the impeller at the location where the outer diameter of the impeller is at its maximum is less than 8 mm in a configuration where the impeller is not radially constrained.

[0064] Inventive Concept 3. The apparatus according to Inventive Concept 1, wherein at least one spiral elongated element includes a plurality of spiral elongated elements, and at least one flexible elongated element extends from a spring to each of the spiral elongated elements.

[0065] Inventive Concept 4. The apparatus according to any one of Inventive Concepts 1 to 3, wherein the impeller is configured to pump blood through the body of the subject. Inventive Concept 5. The apparatus according to Inventive Concept 4, wherein the impeller is configured to be installed in the blood vessel of the subject.

[0066] Inventive Concept 6. The apparatus according to Inventive Concept 4, wherein the impeller is configured to be installed in the heart cavity of the subject. Inventive Concept 7. The impeller pumps blood from the left ventricle of the subject to the aorta of the subject The apparatus according to Inventive Concept 4, which is configured to

[0067] Inventive Concept 8. The apparatus according to Inventive Concept 4, wherein the impeller is configured to pump blood from the right ventricle of the subject to the pulmonary artery of the subject. Inventive Concept 9. A method, the method comprising installing an impeller into the body of the subject, wherein the impeller includes at least one spiral elongated element, a spring disposed along an axis around which the spiral elongated element is wound inside the spiral elongated element, a film of material supported between the spiral elongated element and the spring, and at least one flexible elongated element extending from the spring to the spiral elongated element, wherein the spiral elongated element is at least one flexible elongated element selected from the group consisting of strings and wires and further includes The method also includes A step of pumping blood through a subject's body by rotating an impeller, wherein the flexible elongated element maintains the helical elongated element within a given distance from the spring during rotation of the impeller An apparatus comprising

[0068] Inventive concept 10. An apparatus, the apparatus comprising A blood pump, The blood pump comprising An impeller configured to be disposed inside a heart chamber of a subject, A frame configured to be disposed around the impeller, A motor configured to drive the impeller to pump blood from the heart chamber of the subject to a blood vessel by rotating the impeller And comprising The impeller is configured to experience axial movement relative to the frame in response to a periodic change in the pressure difference between the heart chamber and the blood vessel. An apparatus

[0069] Inventive concept 11. A method, the method comprising Installing an impeller of a blood pump inside a heart chamber of a subject with a frame disposed around the impeller, Driving the impeller to pump blood from the heart chamber of the subject to a blood vessel by rotating the impeller And comprising The installation of the impeller inside the heart chamber is such that the impeller is allowed to experience axial movement relative to the frame in response to a periodic change in the pressure difference between the heart chamber and the blood vessel. A method

[0070] Inventive concept 12. An apparatus, the apparatus comprising A blood pump, The blood pump comprising An impeller configured to be disposed inside a first blood vessel of a subject, A frame configured to be disposed around the impeller, A motor configured to drive an impeller to pump blood from a first blood vessel of a subject to a second blood vessel by rotating the impeller, and comprising An apparatus, wherein the impeller is configured to experience axial movement relative to the frame in response to a periodic change in the pressure difference between the first blood vessel and the second blood vessel.

[0071] Inventive concept 13. A method, the method comprising Installing an impeller of a blood pump inside a first blood vessel of a subject with the frame disposed around the impeller; and Driving the impeller to pump blood from the first blood vessel of the subject to a second blood vessel by rotating the impeller comprising A method, wherein the installation of the impeller inside the first blood vessel allows the impeller to experience axial movement relative to the frame in response to a periodic change in the pressure difference between the heart chamber and the blood vessel.

[0072] Inventive concept 14. An apparatus, the apparatus comprising A blood pump The blood pump comprising An impeller configured to be installed inside the body of a subject, configured to rotate, and configured to pump blood through the body of the subject; A frame configured to be disposed around the impeller; and One or more thrust bearings configured to be disposed outside the body of the subject, wherein the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject. comprising

[0073] Inventive concept 15. A method, the method comprising The step of installing an impeller of a blood pump inside the body of a subject with a frame disposed around the impeller; The step of driving the impeller to pump blood through the body of the subject by rotating the impeller, wherein counteraction to the thrust generated by the rotation of the impeller is provided only by one or more thrust bearings disposed outside the body of the subject; A method comprising the above.

[0074] Inventive concept 16. An apparatus, comprising: A blood pressure pump tube; A blood pump configured to be disposed in the blood pressure pump tube and to pump blood through the blood pressure pump tube; At least one blood pressure measurement tube defining an opening at its distal end and configured to extend at least to the outer surface of the blood pressure pump tube, with the opening at the distal end of the blood pressure measurement tube in direct fluid communication with the blood flow of the subject outside the blood pressure pump tube; At least one pressure sensor configured to measure the pressure of the blood flow of the subject outside the blood pressure pump tube by measuring the pressure of the blood in the blood pressure measurement tube; An apparatus comprising the above.

[0075] Inventive concept 17. The apparatus according to inventive concept 16, wherein the blood pump includes an impeller configured to pump blood through the blood pressure pump tube by rotating.

[0076] Inventive concept 18. The apparatus according to inventive concept 16, wherein the blood pressure measurement tube is configured to run along the outer surface of the blood pressure pump tube from the proximal end of the blood pressure pump tube to the opening at the distal end of the blood pressure measurement tube.

[0077] Inventive Concept 19. The device further includes at least one computer processor, the at least one computer processor being configured to receive an indication of blood pressure measured within a blood pressure measurement tube and, in response to the blood pressure measured within the blood pressure pump tube, to control the pumping of blood by a blood pump, the device according to Inventive Concept 16.

[0078] Inventive Concept 20. The at least one blood pressure measurement tube includes at least one left ventricular blood pressure measurement tube, the at least one left ventricular blood pressure measurement tube being configured to extend to the outer surface of the blood pressure pump tube at a location along a tube configured to be within the left ventricle of the subject proximal to the blood pump, the pressure sensor being configured to measure the left ventricular pressure of the subject by measuring the pressure of the blood within the left ventricular blood pressure measurement tube, the device according to any one of Inventive Concepts 16 - 19.

[0079] Inventive Concept 21. The at least one blood pressure measurement tube includes two or more left ventricular blood pressure measurement tubes, the two or more left ventricular blood pressure measurement tubes being configured to extend to the outer surface of the blood pressure pump tube at a location along a blood pressure pump tube configured to be within the left ventricle of the subject proximal to the blood pump, at least one pressure sensor being configured to measure the left ventricular pressure of the subject by measuring the pressure of the blood within at least one of the left ventricular blood pressure measurement tubes, the device according to Inventive Concept 20.

[0080] Inventive Concept 22. At least one pressure sensor is configured to measure the pressure of the blood within each of the two or more left ventricular blood pressure measurement tubes, The device further includes at least one computer processor, the at least one computer processor being configured to receive an indication of blood pressure measured within each of two or more left ventricular blood pressure measurement tubes, in response, configured to determine that one of the openings of one of the two or more left ventricular blood pressure measurement tubes is blocked, in response, the apparatus according to inventive concept 21, configured to determine a left ventricular pressure of a subject based on blood pressure measured in a different one of the two or more left ventricular blood pressure measurement tubes.

[0081] Inventive concept 23. At least one blood pressure measurement tube further includes at least one aortic blood pressure measurement tube, the at least one aortic blood pressure measurement tube being configured to extend to the outer surface of the blood pressure pump tube at a location along the blood pressure pump tube configured to be within the aorta of the subject, the pressure sensor being configured to measure the aortic pressure of the subject by measuring the pressure of the blood in the aortic blood pressure measurement tube, the apparatus according to inventive concept 20.

[0082] Inventive concept 24. At least one aortic blood pressure measurement tube includes two or more aortic blood pressure measurement tubes, the two or more aortic blood pressure measurement tubes being configured to be within the aorta of the subject at a location along the blood pressure pump tube configured to extend to the outer surface of the blood pressure pump tube, at least one pressure sensor being configured to measure the aortic pressure of the subject by measuring the pressure of the blood in at least one of the aortic blood pressure measurement tubes, the apparatus according to inventive concept 23.

[0083] Inventive Concept 25. At least one blood pressure measurement tube includes at least one aortic blood pressure measurement tube, and at least one aortic blood pressure measurement tube is configured to extend to the outer surface of the blood pressure pump tube at a location along the blood pressure pump tube such that it is in the aorta of the subject, and the pressure sensor is configured to measure the aortic pressure of the subject by measuring the pressure of the blood in the aortic blood pressure measurement tube, the device according to any one of Inventive Concepts 16 to 19.

[0084] Inventive Concept 26. At least one aortic blood pressure measurement tube includes two or more aortic blood pressure measurement tubes, and two or more aortic blood pressure measurement tubes are configured to extend to the outer surface of the blood pressure pump tube at a location along the blood pressure pump tube such that they are in the aorta of the subject, and at least one pressure sensor is configured to measure the aortic pressure of the subject by measuring the pressure of the blood in at least one of the aortic blood pressure measurement tubes, the device according to Inventive Concept 25.

[0085] Inventive Concept 27. At least one pressure sensor is configured to measure the pressure of the blood in each of two or more aortic blood pressure measurement tubes, The device further includes at least one computer processor, and the at least one computer processor is configured to receive an indication of the blood pressure measured in each of two or more aortic blood pressure measurement tubes, and in response, is configured to determine that an opening of one of the two or more aortic blood pressure measurement tubes is blocked, and in response, is configured to determine the aortic pressure of the subject based on the blood pressure measured in a different one of the two or more aortic blood pressure measurement tubes, the device according to Inventive Concept 26.

[0086] Inventive concept 28. The blood pressure measurement tube is configured to extend from outside the subject's body to an opening at the distal end, and at least one pressure sensor is configured to be disposed outside the subject's body, the apparatus according to any one of inventive concepts 16 to 19.

[0087] Inventive concept 29. The blood pump includes an impeller disposed on an axial shaft, the impeller being configured to pump blood from the left ventricle to the aorta by rotation, and the apparatus is a motor disposed outside the subject's body, the motor being configured to drive the impeller to rotate, the motor, and is a drive cable extending from outside the subject's body to the axial shaft, the drive cable being configured to impart rotational motion from the motor to the impeller by rotation, the drive cable, and is an outer tube configured to extend from outside the subject's body into the blood pressure pump tube, and further includes, the drive cable and the blood pressure measurement tube are configured to be disposed in the outer tube, the apparatus according to inventive concept 28.

[0088] Inventive concept 30. At least one blood pressure measurement tube includes at least one left ventricular blood pressure measurement tube, the at least one left ventricular blood pressure measurement tube being configured to extend to the outer surface of the blood pressure pump tube at a location along the blood pressure pump tube that is configured to be in the subject's left ventricle proximal to the blood pump, and at least one pressure sensor is configured to measure the subject's left ventricular pressure by measuring the pressure of the blood in the left ventricular blood pressure measurement tube. The device further includes an aortic blood pressure measurement tube, the aortic blood pressure measurement tube defining an opening at its distal end, the aortic blood pressure measurement tube being configured to extend from outside the subject's body to the outer surface of the outer tube within the subject's aorta, such that the opening at the distal end of the blood pressure measurement tube is in direct fluid communication with the subject's aortic blood flow. The device according to inventive concept 29, wherein at least one pressure sensor is further configured to measure the subject's aortic pressure by measuring the pressure of the blood within the aortic blood pressure measurement tube.

[0089] Inventive concept 31. At least one blood pressure measurement tube includes at least one left ventricular blood pressure measurement tube, the at least one left ventricular blood pressure measurement tube being configured to extend to the outer surface of the blood pressure pump tube at a location along the blood pressure pump tube that is proximal to the blood pump and within the subject's left ventricle, and at least one pressure sensor being configured to measure the subject's left ventricular pressure by measuring the pressure of the blood within the left ventricular blood pressure measurement tube. The device further includes an aortic blood pressure measurement tube, the aortic blood pressure measurement tube defining an opening at its distal end, the aortic blood pressure measurement tube being configured to extend from outside the subject's body to a portion of the outer surface of the outer tube disposed within the blood pressure pump tube, such that the opening at the distal end of the blood pressure measurement tube is in direct fluid communication with the subject's aortic blood flow. The device according to inventive concept 29, wherein at least one pressure sensor is further configured to measure the subject's aortic pressure by measuring the pressure of the blood within the aortic blood pressure measurement tube.

[0090] Inventive Concept 32. The outer tube defines a groove in a portion of the outer surface of the outer tube configured to be disposed within the blood pressure pump tube, and during insertion of the ventricular assist device into the body of the subject, a portion of the blood pressure measurement tube configured to extend from within the blood pressure pump tube to the outer surface of the blood pressure pump tube is configured to be disposed within the groove such that that portion of the blood pressure measurement tube does not protrude from the outer surface of the outer tube, the device according to Inventive Concept 29.

[0091] Inventive Concept 33. The diameter of the blood pressure measurement tube, at least in the distal portion of the blood pressure measurement tube, is less than 0.5 mm, the device according to Inventive Concept 28. Inventive Concept 34. The diameter of the blood pressure measurement tube, at least in the distal portion of the blood pressure measurement tube, is greater than 0.2 mm, the device according to Inventive Concept 33.

[0092] Inventive Concept 35. A method, the method comprising: a blood pressure pump tube, a blood pump disposed within the blood pressure pump tube, and at least one blood pressure measurement tube, the at least one blood pressure measurement tube defining an opening at its distal end, the at least one blood pressure measurement tube extending at least to the outer surface of the blood pressure pump tube such that the opening at the distal end of the blood pressure measurement tube is in direct fluid communication with the bloodstream of the subject outside the blood pressure pump tube, installing the at least one blood pressure measurement tube into the body of the subject ; pumping blood through the blood pressure pump tube using the blood pump; and measuring the pressure of the bloodstream of the subject outside the blood pressure pump tube by measuring the pressure of the blood within the blood pressure measurement tube. A method as described above.

[0093] Inventive Concept 36. A device, the device comprising: a blood pump, The blood pump includes a tube and an impeller configured to be disposed within the tube and to rotate to pump blood through the tube, a frame disposed around the impeller, and a stator configured to reduce a rotational flow component from the blood flow generated by rotation of the impeller. The stator includes a plurality of struts integral with the frame and curved, and a flexible material coupled to the curved struts to form a plurality of curved protrusions. The device

[0094] Inventive concept 37. The device according to inventive concept 36, wherein the curvature of the curved protrusions opposes the direction of rotation of the impeller. Inventive concept 38. The device according to inventive concept 36, wherein the curvature of the curved protrusions becomes progressively closer from the distal end of the curved protrusions to the proximal end of the curved protrusions such that the curved protrusions are parallel to the longitudinal axis of the frame.

[0095] Inventive concept 39. The device according to inventive concept 36, wherein the flexible material is shaped to define a lumen therethrough. Inventive concept 40. A method including implanting a blood pump into a subject's body, wherein the blood pump includes a tube and an impeller configured to be disposed within the tube, a frame disposed around the impeller, A stator including a plurality of struts and a flexible material, the plurality of struts being integral with a frame, the plurality of struts being curved, and the flexible material being connected to the curved struts and configured to form a plurality of curved protrusions, and a stator comprising The method further includes pumping blood through a tube using an impeller, the stator reducing a rotational flow component from the blood flow generated by rotation of the impeller A method comprising

[0096] Inventive concept 41. An apparatus, the apparatus comprising a ventricular assist device The ventricular assist device includes an axial shaft an impeller disposed on the axial shaft and configured to be installed in the left ventricle of a subject a motor configured to be disposed outside the body of the subject and configured to drive the impeller to pump blood from the left ventricle of the subject to the aorta by rotating the impeller a drive cable configured to extend from outside the body of the subject to the axial shaft, the drive cable configured to impart rotational movement from the motor to the impeller by rotating, the drive cable including a first portion configured to be disposed at least partially within the aortic arch of the subject and a second portion configured to be disposed at least partially within the descending aorta of the subject comprising The first portion of the drive cable includes a first number of wires disposed in a coiled configuration, the second portion of the drive cable includes a second number of wires disposed in a coiled configuration, and the first number is less than the second number. An apparatus

[0097] Inventive Concept 42. The device according to Inventive Concept 41, wherein the length of the first portion of the drive cable is between 20 cm and 40 cm. Inventive Concept 43. The device according to Inventive Concept 41, wherein the length of the second portion of the drive cable is between 60 cm and 100 cm.

[0098] Inventive Concept 44. The device according to Inventive Concept 41, wherein the first portion of the drive cable includes between 4 and 8 wires arranged in a coiled configuration, and the second portion of the drive cable includes between 8 and 12 wires arranged in a coiled configuration.

[0099] Inventive Concept 45. A device, the device comprising: a blood pump, wherein the blood pump comprises: an axial shaft, and an impeller disposed on the axial shaft, a motor configured to be disposed outside the body of the subject, the motor being configured to drive the impeller to pump blood through the body of the subject by rotating the impeller, a drive cable configured to extend from outside the body of the subject to the axial shaft, the drive cable being configured to impart rotational motion from the motor to the impeller by rotating, the drive cable including a first portion configured to be at least partially disposed within a curved portion of the subject's vascular system and a second portion configured to be at least partially disposed within a straight portion of the subject's vascular system, and wherein the first portion of the drive cable includes a first number of wires arranged in a coiled configuration, the second portion of the drive cable includes a second number of wires arranged in a coiled configuration, and the first number is smaller than the second number.

[0100] Inventive concept 46. An apparatus, the apparatus comprising: a blood pump; the blood pump comprising: an axially extending shaft; an impeller disposed on the axially extending shaft; a motor configured to be disposed outside the body of a subject, the motor being configured to drive the 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; a drive cable configured to extend from outside the body of the subject to the axially extending shaft, the drive cable being configured to impart rotational movement from the motor to the impeller by rotating; and at least a portion of the drive cable includes a plurality of wires disposed in a coiled configuration, the coiled configuration being such that in response to the drive cable rotating in a given direction of rotation, the plurality of wires disposed in the coiled configuration are at least partially unwound and a portion of the drive cable is shortened axially.

[0101] Inventive concept 47. The apparatus according to inventive concept 46, wherein the impeller is configured to pump blood from a first location to a second location and is configured to experience an axial forward and backward movement in response to a periodic change in the pressure differential between the first location and the second location.

[0102] Inventive concept 48. A method, the method comprising: installing a blood pump into the body of a subject; the blood pump comprising: an axially extending shaft; an impeller disposed on the axially extending shaft; a drive cable extending from outside the body of the subject to the axially extending shaft; and Furthermore, the method is driving an impeller to pump blood from a distal end of the impeller to a proximal end of the impeller by imparting a rotational movement to the impeller via a drive cable, wherein at least a portion of the drive cable includes a plurality of wires arranged in a coiled configuration, and the coiled configuration is such that in response to the drive cable rotating in a given direction of rotation, the plurality of wires arranged in the coiled configuration are at least partially wound back and a portion of the drive cable is shortened in the axial direction A method comprising.

[0103] Invention concept 49. An apparatus, the apparatus comprising a blood pump The blood pump an axial shaft an impeller disposed on the axial shaft a motor, the motor being configured to be disposed outside the body of the subject, the motor being configured to drive the impeller to pump blood in the proximal direction by rotating the impeller in a given direction of rotation a drive cable, the drive cable being configured to extend from a proximal end of the drive cable disposed outside the body of the subject to a distal end of the drive cable, the distal end of the drive cable being connected to the axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating a drive cable, the drive cable being configured to extend from a proximal end of the drive cable disposed outside the body of the subject to a distal end of the drive cable, the distal end of the drive cable being connected to the axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating an outer tube disposed around the drive cable a fluid disposed between the outer tube and the drive cable and comprising At least a portion of the drive cable includes a plurality of wires disposed in a coiled configuration, the coiled configuration being configured such that, in response to the drive cable rotating in a given direction of rotation, the plurality of wires pump fluid toward the proximal end of the drive cable, apparatus.

[0104] Inventive concept 50. A method, the method comprising: installing a blood pump into a subject's body, the blood pump comprising: an axial shaft, an impeller disposed on the axial shaft, a drive cable extending from outside the subject's body to the axial shaft, the outer tube being disposed around the drive cable, a fluid disposed between the drive cable and the outer tube, and further, the method comprising: driving the impeller to pump blood from the distal end of the impeller to the proximal end of the impeller by imparting a rotational movement to the impeller via the drive cable, at least a portion of the drive cable including a plurality of wires disposed in a coiled configuration, the coiled configuration being configured such that, in response to the drive cable rotating in a given direction of rotation, the plurality of wires pump fluid toward the proximal end of the drive cable, step comprising, method.

[0105] Inventive concept 51. An apparatus, the apparatus comprising: a blood pump, the blood pump comprising: an impeller, A motor configured to drive an impeller for pumping blood by rotating the impeller, wherein the impeller is configured to experience axial movement in response to a change in the pressure differential against which the impeller pumps blood, and the motor. A magnet, wherein the impeller is connected to the magnet and the axial movement of the impeller causes the magnet to experience axial movement. A sensor configured to detect the magnetic flux generated by the magnet and, in response thereto, generate a sensor signal. A computer processor configured to receive the sensor signal and, in response thereto, generate an output. An apparatus comprising the above.

[0106] Inventive concept 52. The computer processor of the apparatus according to inventive concept 51 is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. The apparatus described in inventive concept 51.

[0107] Inventive concept 53. The computer processor of the apparatus according to inventive concept 51 is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal.

[0108] Inventive concept 54. The computer processor of the apparatus according to any one of inventive concepts 51 to 53 is configured to vary the rotational speed of the impeller based at least in part on the sensor signal.

[0109] Inventive concept 55. The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, The device according to inventive concept 54, configured to vary the rotational speed of the impeller based at least in part on a determined left ventricular pressure.

[0110] Inventive concept 56. The device according to inventive concept 55, wherein a computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased.

[0111] Inventive concept 57. A device, the device comprising: a blood pump, wherein the blood pump comprises an impeller, and a motor configured to drive the impeller to pump blood by rotating the impeller, wherein the impeller is configured to experience axial movement in response to a change in the pressure differential against which the impeller pumps blood; a sensor configured to detect an indication of the axial movement of the impeller and, in response thereto, generate a sensor signal; and a computer processor configured to receive the sensor signal and, in response thereto, generate an output. The device includes.

[0112] Inventive concept 58. A method, the method comprising: placing a blood pump inside the body of a subject, the blood pump including an impeller; driving the impeller to pump blood by rotating the impeller, wherein the impeller is configured to experience axial movement in response to a change in the pressure differential against which the impeller pumps blood; detecting an indication of axial movement of the impeller and, in response thereto, generating a sensor signal; receiving a sensor signal and, in response thereto, generating an output; A method comprising:

[0113] Inventive concept 59. An apparatus, comprising: Including a blood pump, The blood pump is The impeller, Frame and Including, the impeller and the frame are configured to be inserted into a body of a subject such that the frame is disposed about the impeller within the body of the subject; The device also includes: An apparatus comprising: a computer processor configured to drive a motor unit to simultaneously (a) drive an impeller to rotate, thereby pumping blood through a subject's body, and (b) drive the impeller to move axially within a frame in a forward and backward motion.

[0114] Inventive concept 60. A method, comprising: placing a blood pump including an impeller and a frame into a body of a subject, the frame being adapted to be disposed around the impeller; at the same time, driving the impeller to rotate and thereby pump blood through the body of the subject; driving the impeller to move axially through the frame in a forward and backward motion; A method comprising:

[0115] Inventive concept 61. An apparatus, comprising: Including a blood pump, The blood pump is an axial shaft, and an impeller, the impeller being disposed on the axial shaft and configured to be installed in the left ventricle of the subject, and a motor, the motor being configured to be disposed outside the body of the subject and configured to drive the impeller to rotate, and a drive cable configured to extend from outside the body of the subject to the axial shaft via the aortic arch of the subject, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating, and a tube, the drive cable being configured to be disposed in the tube during rotation of the drive cable, the tube being configured to remain stationary during rotation of the drive cable, and a plurality of ball bearings, the plurality of ball bearings being configured to be disposed between the drive cable and the tube and to reduce friction between the drive cable and the tube during movement of the drive cable relative to the tube, and an apparatus comprising the same.

[0116] Inventive concept 62. The ball bearings are configured to be disposed between the drive cable and the tube in at least a portion of the drive cable and the tube configured to be disposed in the aortic arch of the subject during rotation of the impeller, of the apparatus according to inventive concept 61.

[0117] Inventive concept 63. An apparatus, the apparatus comprising a blood pump, the blood pump comprising an axial shaft, and an impeller, the impeller being disposed on the axial shaft and configured to be installed inside the body of the subject, and A motor configured to be disposed outside the body of the subject, A drive cable configured to extend from outside the body of the subject to the axial shaft, Exactly two drive magnets disposed in the drive magnet housing, the drive magnet housing being connected to the motor, exactly two drive magnets, and A driven magnet, the driven magnet being connected to the drive cable and also disposed between the drive magnets such that there is an axial overlap between the drive magnet and the driven magnet, the driven magnet defining a single N pole and a single S pole divided along the axial length of the driven magnet, the motor being configured to impart a rotational motion to the impeller by rotating the drive magnet housing, thereby rotating the driven magnet, thereby rotating the drive cable, and An apparatus including.

[0118] Inventive concept 64. A method, the method comprising Installing a blood pump into the body of the subject, The blood pump includes An axial shaft, An impeller disposed on the axial shaft, A drive cable extending from outside the body of the subject to the axial shaft, and Including, Also, the method includes Driving the impeller to rotate by using a motor to rotate exactly two drive magnets disposed in a drive magnet housing connected to the motor, Including, The driving magnet is configured to drive the driven magnet to rotate thereby, the driven magnet is connected to the drive cable, is disposed between the driving magnets, and an axial overlap is present between the driving magnet and the driven magnet, and the driven magnet defines a single N pole and a single S pole that are divided along the axial length of the driven magnet, method.

[0119] Inventive concept 65. An apparatus, the apparatus comprising a blood pump, the blood pump comprising an axial shaft, an impeller, the impeller being disposed on the axial shaft and configured to be installed inside the body of the subject, a motor configured to be disposed outside the body of the subject, a drive cable configured to extend from outside the body of the subject to the axial shaft, exactly two driven magnets disposed in the driven magnet housing, the driven magnet housing being connected to the motor, a driving magnet, the driving magnet being connected to the motor and also disposed between the driven magnets, an axial overlap being present between the driven magnet and the driving magnet, the driving magnet defining a single N pole and a single S pole that are divided along the axial length of the driving magnet, the motor being configured to rotate the driving magnet thereby, by rotating the driven magnet, by rotating the drive cable, to impart a rotational movement to the impeller, and including the driving magnet.

[0120] Inventive concept 66. A method, the method comprising the step of installing a blood pump into the body of the subject, the blood pump comprising an axial shaft, An impeller disposed on an axial shaft, and A drive cable extending from outside the subject's body to the axial shaft and comprising Also, the method is A step of driving the impeller to rotate by using a motor to rotate a drive magnet connected to the motor, wherein the drive magnet defines a single N pole and a single S pole divided along the axial length of the drive magnet comprising The drive magnet is thereby configured to drive a driven magnet to rotate, and the driven magnet accurately includes two driven magnets disposed in a driven magnet housing, and the driven magnet housing is connected to the drive cable and disposed around the drive magnet. Method

[0121] Inventive concept 67. An apparatus, the apparatus comprising A blood pump, and The blood pump An axial shaft, and An impeller, the impeller being disposed on the axial shaft and also configured to be installed inside the subject's body A motor, the motor being configured to be disposed outside the subject's body and also configured to drive the impeller to pump blood by rotating the impeller in a given direction of rotation A drive cable configured to extend from outside the subject's body to the axial shaft, the drive cable being configured to impart a rotational motion from the motor to the impeller by rotating, the drive cable including a plurality of wires, the plurality of wires being disposed in a coiled configuration and the plurality of wires being connected to the axial shaft comprising The axial shaft defines a groove at the interface between the drive cable and the axial shaft, and the groove is configured such that the stress generated by the wire at the interface is spread over the radius of the groove, the device.

[0122] Inventive concept 68. A device, the device comprising: A blood pump, The blood pump comprising: An axial shaft, An impeller disposed on the axial shaft and configured to be installed inside the body of the subject, the impeller; A motor configured to be disposed outside the body of the subject and configured to drive the impeller to pump blood by rotating the impeller in a given direction of rotation, the motor; A drive cable configured to extend from outside the body of the subject to the axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating, the drive cable including a plurality of wires, the plurality of wires being arranged in a coiled configuration, the plurality of wires being connected to the axial shaft, the drive cable; Including, The coiled wire is shaped such that the pitch of the wire is increased as the coiled wire approaches the interface between the drive cable and the axial shaft, and the stress at the location where the wire of the drive cable is connected to the axial shaft is reduced compared to the case where the pitch of the wire is not increased, the device.

[0123] Inventive concept 69. A device, the device comprising: A blood pump, The blood pump comprising: An axial shaft, An impeller, the impeller being disposed on an axial shaft and configured to be installed inside the body of a subject, the impeller; A motor, the motor being configured to be disposed outside the body of the subject and configured to drive the impeller to pump blood by rotating the impeller in a given direction of rotation, the motor; A drive cable configured to extend from outside the body of the subject to the axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating; The drive cable includes first and second portions, the first portion of the drive cable includes a first number of wires disposed in a coiled configuration, the second portion of the drive cable includes a second number of wires disposed in a coiled configuration, the first number being less than the second number, the drive cable; An interface component, the first and second portions of the drive cable being connected to each other via the interface component; The interface component defines a groove at the interface between at least one of the drive cable portions and the interface component, the groove being configured such that the stress generated by the wires at the interface is spread over the radius of the groove, the interface component; An apparatus comprising.

[0124] Inventive concept 70. An apparatus, the apparatus comprising A blood pump; The blood pump comprising An axial shaft; An impeller, the impeller being disposed on the axial shaft and configured to be installed inside the body of a subject, the impeller; A motor, the motor being configured to be disposed outside the body of a subject and further configured to drive an impeller to pump blood by rotating the impeller in a given direction of rotation, the motor; A drive cable configured to extend from outside the body of the subject to an axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating; The drive cable includes first and second portions, the first portion of the drive cable includes a first number of wires disposed in a coiled configuration, the second por tion of the drive cable includes a second number of wires disposed in a coiled configuration, the first number being smaller than the second number, the drive cable; An interface component, the first and second portions of the drive cable being connected to each other via the interface component; At least one of the coiled wires of a portion of the drive cable is shaped such that the pitch of the wire is increased as the coiled wire approaches the interface component, and the stress at the location where the wire is connected to the interface component is reduced compared to the case where the pitch of the wire is not increased, the interface component; An apparatus including the same.

[0125] Inventive concept 71. An apparatus, the apparatus comprising: A ventricular assist device; The ventricular assist device comprising: A tube, the tube being configured to traverse the aortic valve of the subject, with the proximal portion of the tube disposed within the aorta of the subject and the distal portion of the tube disposed within the left ventricle of the subject, the tube defining one or more blood inlet openings within the distal portion of the tube and one or more blood outlet openings within the proximal portion of the tube, the tube; A blood pump, the blood pump being configured to be disposed within a tube and to pump blood from the left ventricle into the tube through one or more blood inlet openings and from the tube into the aorta outside the tube through one or more blood outlet openings, a blood pump; A radially expandable atraumatic distal tip portion, the radially expandable atraumatic distal tip portion being configured to be disposed within the left ventricle of the subject distal to one or more blood inlet openings, the distal tip portion being configured to be inserted into the left ventricle in a radially constrained configuration and further configured to assume a non-radially constrained configuration within the left ventricle of the subject, in the non-radially constrained configuration, at least the radially expandable portion of the distal tip portion being radially expanded relative to the radially constrained configuration of the distal tip portion, a radially expandable atraumatic distal tip portion; An apparatus comprising.

[0126] Inventive concept 72. The apparatus according to inventive concept 71, wherein the distal tip portion comprises a braided shape memory alloy at least partially covered by a blood-impermeable material. Inventive concept 73. The apparatus according to inventive concept 71, wherein in the non-radially constrained configuration of the distal tip portion, the radially expandable portion of the distal tip portion is configured to separate one or more blood inlet openings from the interventricular septum in the left ventricle.

[0127] Inventive concept 74. The apparatus according to inventive concept 71, wherein in the non-radially constrained configuration of the distal tip portion, the radially expandable portion of the distal tip portion is configured to separate one or more blood inlet openings from the chordae tendineae in the left ventricle.

[0128] Inventive Concept 75. The device according to Inventive Concept 71, wherein the distal tip portion is configured such that, in a configuration where the distal tip portion is not radially constrained, a radially expandable portion of the distal tip portion separates one or more blood inlet openings from the papillary muscles in the left ventricle.

[0129] Inventive Concept 76. The device according to Inventive Concept 71, wherein the distal tip portion is configured such that, in a configuration where the distal tip portion is not radially constrained, a radially expandable portion of the distal tip portion separates one or more blood inlet openings from the apex in the left ventricle.

[0130] Inventive Concept 77. The device according to Inventive Concept 71, wherein the distal tip portion is configured such that, in a configuration where the distal tip portion is not radially constrained, a radially expandable portion of the distal tip portion three-dimensionally separates one or more blood inlet openings from the inner structure in the left ventricle.

[0131] Inventive Concept 78. The device according to Inventive Concept 71, wherein the distal tip portion is configured such that, in a configuration where the distal tip portion is not radially constrained, a radially expandable portion of the distal tip portion directs blood flow into one or more blood inlet openings from the left ventricle.

[0132] Inventive Concept 79. In a configuration where the distal tip portion is radially constrained, the distal region of the distal tip portion is configured to be at least semi-rigid and is shaped to converge radially along the longitudinal direction toward the distal end of the distal tip portion. The ventricular assist device is configured to be inserted into the subject's body through a puncture site in the subject's body. During insertion of the ventricular assist device, the distal region of the distal tip portion is configured to act as a dilator by expanding the puncture site, for the device according to any one of Inventive Concepts 71 to 78.

[0133] Inventive Concept 80. The device according to any one of Inventive Concepts 71 to 78, wherein the distal tip portion is configured such that, in a configuration where the distal tip portion is not radially constrained, the distal end of the distal tip portion is enclosed within a radially expandable portion of the distal tip portion.

[0134] Inventive Concept 81. The device according to Inventive Concept 80, wherein the distal tip portion is configured such that, by enclosing the distal end of the distal tip portion within a radially expanded portion of the distal tip, the distal end of the distal tip portion is prevented from becoming entangled with the chordae tendineae of the left ventricle.

[0135] Inventive Concept 82. The device according to Inventive Concept 80, wherein the distal tip portion is configured such that, by enclosing the distal end of the distal tip portion within a radially expandable portion of the distal tip portion, the distal end of the distal tip portion is prevented from causing trauma to the internal structures of the left ventricle.

[0136] Inventive Concept 83. The device according to Inventive Concept 80, wherein the distal end of the distal tip portion is configured such that, by inverting the distal end of the distal tip portion, it is enclosed within a radially expandable portion of the distal tip portion.

[0137] Inventive Concept 84. The distal end of the distal tip portion is configured such that, by retracting the distal end of the distal tip portion proximally, it is enclosed within a radially expandable portion of the distal tip portion, and the distal end is arranged to be disposed within a radially expandable portion of the distal tip portion. The device according to Inventive Concept 80.

[0138] Inventive Concept 85. A device, the device comprising a ventricular assist device configured to be inserted into the body of a subject through a puncture portion, the ventricular assist device A tube, the tube being configured to traverse the aortic valve of a subject, with the proximal portion of the tube disposed within the aorta of the subject and the distal portion of the tube being disposed within the left ventricle of the subject, the tube defining one or more blood inlet openings within the distal portion of the tube and one or more blood outlet openings within the proximal portion of the tube, the tube and A blood pump, the blood pump being configured to be disposed within the tube and further configured to pump blood from the left ventricle into the tube through one or more blood inlet openings and from the tube into the aorta outside through one or more blood outlet openings, the blood pump and A distal tip portion, The distal tip portion is configured to have a radially constrained configuration, in which the distal region of the distal tip portion is at least partially rigid and shaped to converge radially along the longitudinal direction towards the distal end of the distal tip portion, the distal region being configured to act as a dilator by expanding a puncture portion during insertion of the ventricular assist device into the body of the subject. Also, the distal tip portion is configured to have a non-radially constrained configuration, the distal tip region being configured to take a non-radially constrained configuration within the left ventricle of the subject, in which the radially expandable portion of the distal tip portion is configured to be non-invasive and also configured to separate one or more blood inlet openings from the internal structure of the left ventricle of the subject, the distal tip portion An apparatus comprising.

[0139] Concept 86. A method, the method comprising The step of operating a blood pump, The blood pump is An axial shaft, An impeller, the impeller being disposed on an axial shaft and also disposed within the left ventricle of a subject, the impeller, and A motor, the motor being disposed outside the body of the subject and configured to drive the impeller to rotate, the motor, and A drive cable, the drive cable extending from outside the body of the subject to the axial shaft via the aortic arch of the subject and configured to impart a rotational movement from the motor to the impeller by rotating, the drive cable, and A tube, the drive cable being disposed within the tube, the tube being configured to remain stationary during rotation of the drive cable, the tube comprising, Also, the method is While operating the blood pump, pumping a fluid into the space between the drive cable and the tube, the fluid being configured to fill the space between the drive cable and the tube but not to be released into the bloodstream of the subject, the step comprising, the method.

[0140] Inventive concept 87. A method, the method being comprising the step of operating a blood pump, The blood pump is an axial shaft, and an impeller, the impeller being disposed on the axial shaft and also disposed within the left ventricle of a subject, the impeller, and a motor, the motor being disposed outside the body of the subject and configured to drive the impeller to rotate, the motor, and a drive cable, the drive cable extending from outside the body of the subject to the axial shaft via the aortic arch of the subject and configured to impart a rotational movement from the motor to the impeller by rotating, the drive cable, and A tube, wherein a drive cable is disposed within the tube, and the tube is configured to remain stationary during rotation of the drive cable, the tube and comprising Also, the method is Before operating the blood pump, pumping fluid into the space between the drive cable and the tube, such that the fluid fills the space between the drive cable and the tube, but without releasing the fluid into the bloodstream of the subject, the step and During operation of the blood pump, leaving fluid in the space between the drive cable and the tube and comprising the method.

[0141] Inventive concept 88. An apparatus, the apparatus comprising A left ventricular assist device configured to assist the left ventricular function of a subject, The left ventricular assist device A tube, the tube being configured to cross the aortic valve of the subject, with the proximal portion of the tube at least partially disposed within the ascending aorta of the subject and the distal portion of the tube at least partially disposed within the left ventricle of the subject, the tube and A frame disposed within the distal portion of the tube, the frame being configured to hold the distal portion of the tube in an open state, The frame is not disposed within the proximal portion of the tube, and the proximal portion of the tube is thereby configured to collapse inwardly in response to the pressure outside the proximal portion of the tube exceeding the pressure inside the proximal portion of the tube, the frame and A pump, the pump being disposed within the frame and also configured to pump blood from the left ventricle of the subject to the aorta of the subject through the tube, such that when the blood pressure generated within the proximal portion of the tube by the blood pump exceeds the aortic pressure of the subject outside the proximal portion of the tube, the proximal portion of the tube is maintained in an open state, the pump and A plurality of elongated commissure elements, wherein the plurality of elongated commissure elements are disposed within a proximal portion of the tube and are adapted to form cusps in which respective portions of the peripheral portion of the tube contact each other when the proximal portion of the tube collapses inwardly, and the plurality of elongated commissure elements An apparatus comprising

[0142] Inventive concept 89. The apparatus further includes a computer processor configured to control the pumping of blood through the tube by a blood pump, wherein the blood pressure generated by the blood pump in the tube exceeds the systolic aortic pressure of the subject and is less than the diastolic aortic pressure of the subject, the apparatus according to inventive concept 88.

[0143] Inventive concept 90. The apparatus further includes a pressure sensor configured to measure the aortic blood pressure of the subject, wherein the computer processor is configured to receive an indication of the measured aortic blood pressure and to control the pumping of blood through the tube by a blood pump in response to the measured aortic blood pressure, the apparatus according to inventive concept 88.

[0144] Inventive concept 91. The apparatus further includes a pressure sensor configured to measure the left ventricular blood pressure of the subject, wherein the computer processor is configured to receive an indication of the measured left ventricular blood pressure and to control the pumping of blood through the tube by a blood pump in response to the measured left ventricular blood pressure, the apparatus according to inventive concept 88.

[0145] Inventive concept 92. An apparatus for use with a delivery device, the apparatus comprising An impeller, and A frame disposed around the impeller, wherein The impeller and the frame are configured to be inserted into a blood vessel of a subject via a delivery device while being arranged in a radially constrained configuration, and further configured to assume a non-radially constrained configuration when released from the delivery device, a frame, A coupling element including a first portion and a second portion, the first portion being disposed on the impeller, the second portion being disposed on the frame, the first portion being configured to engage with the coupling element, the coupling element being configured to promote radial contraction of the impeller by holding an end portion of the impeller, and the impeller being able to be elongated in the axial direction without radially contracting the frame, a coupling element and An apparatus comprising.

[0146] Inventive concept 93. An apparatus, the apparatus comprising A blood pressure pump tube, An impeller configured to be disposed in the blood pressure pump tube and configured to pump blood from a first location to a second location by pumping blood through the blood pressure pump tube, an impeller, A motor disposed outside the body of the subject and configured to drive the impeller to rotate, a motor, A drive cable extending from outside the body of the subject to an axial shaft and configured to impart rotational movement from the motor to the impeller by rotating, a drive cable, An outer tube disposed around the drive cable configured to extend from outside the body of the subject into the blood pressure pump tube, the outer tube defining first and second openings on a portion of the outer tube disposed in the blood pressure pump tube, an outer tube, A flow obstruction, the flow obstruction being disposed above the first opening and configured such that the first opening functions as a stagnation point pressure tap, and the second opening being configured to function as a static pressure tap, the flow obstruction and At least one pressure sensor configured to measure the pressure in the stagnation point pressure tap and the pressure in the static pressure tap, and A computer processor configured to determine the flow through the blood pressure pump tube based at least in part on the pressure measured in the stagnation point pressure tap and the pressure measured in the static pressure tap An apparatus comprising.

[0147] Inventive concept 94. A method, the method comprising Inserting a blood pump into a subject, The blood pump comprising An impeller including proximal and distal bushings, A frame disposed around the impeller, the frame including a proximal bearing and a distal bearing, the frame and An axial shaft passing through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller, the proximal bushing of the impeller being connected to the axial shaft and configured to be held in an axially fixed position relative to the axial shaft, the distal bushing of the impeller not being connected to the axial shaft and not configured to be held in an axially fixed position relative to the axial shaft, the axial shaft and Including, The impeller being maintained in a radially constrained configuration by a delivery catheter while the impeller is inserted into the subject's body, Also, the method comprising When the impeller is disposed within the subject's body, by releasing the impeller from the catheter, enabling the distal bushing to slide over the axial shaft, causing the impeller to change from its radially constrained configuration to a non-radially constrained configuration; While the impeller is disposed in a non-radially constrained configuration, pumping blood through the subject's body using the impeller. A method comprising:

[0148] Inventive concept 95. A method, the method comprising: Installing an impeller of a ventricular assist device inside the left ventricle of a subject with a frame disposed around the impeller; Driving the impeller to pump blood from the left ventricle of the subject to the aorta by rotating the impeller. Including: The installation of the impeller inside the left ventricle is adapted to allow the impeller to experience axial movement relative to the frame in response to periodic changes in the pressure difference between the left ventricle and the aorta. A method.

[0149] Inventive concept 96. A method, the method comprising: Installing a blood pump inside the subject, The blood pump comprising: An impeller, the impeller comprising a frame disposed around the impeller, the impeller including a proximal bushing and a distal bushing, the frame including a proximal bearing and a distal bearing; An axial shaft, the axial shaft passing through a proximal bearing and a distal bearing of a frame, as well as a proximal bushing and a distal bushing of an impeller, the axial shaft being connected to at least one of the proximal bushing and the distal bushing of the impeller, at least one bushing being held in a position fixed axially with respect to the axial shaft, and not being held in a position fixed axially with respect to the proximal bearing and the distal bearing, the axial shaft and including The method also includes steps of pumping blood through a subject's body using an impeller The method.

[0150] Inventive concept 97. A method, the method comprising Installing an impeller of a blood pump inside a subject's body with the frame disposed around the impeller; Driving the impeller to pump blood through the subject's body without using any thrust bearings disposed within the subject's body to provide counteraction to the thrust generated by rotation of the impeller The method.

[0151] The present invention will be more fully understood from the following detailed description of its embodiments in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0152]

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Embodiments for Carrying Out the Invention

[0153] Here, FIGS. 1A and 1B are referred to. FIGS. 1A and 1B are schematic explanatory diagrams of a ventricular assist device 20 according to some application examples of the present invention. The distal end of the ventricular assist device 20 is disposed in the left ventricle 22 of the subject. The ventricular assist device includes a tube 24, and the tube 24 crosses the aortic valve 26 of the subject. The proximal end 28 of the tube is disposed in the aorta 30 of the subject, and the distal end 32 of the tube is disposed in the left ventricle 22. The tube 24 (which may be referred to herein as the "blood pressure pump tube") is typically an elongated tube, and the axial length of the tube is typically substantially larger than its diameter. The scope of the present invention includes using the devices and methods described herein in anatomical locations other than the left ventricle and aorta. Therefore, the ventricular assist device and / or a part thereof may be referred to herein (in the specification and claims) as a blood pump.

[0154] As shown in FIG. 1B (FIG. 1B shows the steps in the deployment of the ventricular assist device within the left ventricle), typically, the distal end of the ventricular assist device is guided over guide wire 10 into the left ventricle. During insertion of the distal end of the device into the left ventricle, delivery catheter 143 is disposed over the distal end of the device. Once the distal end of the device is disposed within the left ventricle, the delivery catheter is typically retracted into the aorta and the guide wire is withdrawn from the subject's body. Retraction of the delivery catheter typically causes the self-expanding component of the distal end of the device to assume a configuration in which it is not radially constrained, as will be described in more detail hereinafter. Typically, the ventricular assist device is inserted into the subject's body to provide acute treatment to the subject. For some applications, 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, which causes the self-expanding component of the distal end of the device to assume a radially constrained configuration. Alternatively or additionally, the distal end of the device is retracted into the delivery catheter, which causes the self-expanding component of the distal end of the device to assume a radially constrained configuration.

[0155] Also, reference is made to FIGS. 2A, 2B, and 2C, which are schematic illustrations of the blood pump portion 27 of a ventricular assist device 20 according to some applications of the present invention. Typically, impeller 50 is disposed within the distal portion 102 of tube 24 and is configured to pump blood from the left ventricle into the aorta by rotating. The tube typically defines one or more blood inlet openings 108 at the distal end of the tube through which blood flows from the left ventricle into the tube during operation of the impeller. 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 operation of the impeller.

[0156] For some applications, the control console 21 typically includes a computer processor 25 (shown in FIG. 1A), and the control console 21 drives the impeller to rotate. For example, the computer processor can control a motor 74 (shown in FIG. 7), the motor 74 is disposed within the motor unit 23, and the motor 74 drives the impeller to rotate via a drive cable 130 (also shown in FIG. 7). For some applications, the computer processor is configured to detect physiological parameters of the subject (e.g., left ventricular pressure, cardiac afterload, etc.), and, as will be described in more detail hereinafter, is configured to control the rotation of the impeller in response thereto. Typically, the operations described herein that are performed by the computer processor transform the physical state of the memory (which is a real physical article in communication with the computer processor), and depending on the technology of the memory being used, have different magnetic polarities, electrical charges, etc. The computer processor 25 is typically a hardware device programmed by computer program instructions to create a special-purpose computer. For example, when programmed to implement the techniques described herein, the computer processor 25 typically acts as a special-purpose ventricular assist computer processor. For some applications, the purging system 29 drives a fluid (e.g., a glucose solution) to pass through a portion of the ventricular assist device 20, for example, to cool a portion of the device and / or to wash debris from a portion of the device. The purging system 29 will be described in more detail hereinafter.

[0157]

[0158] ​Typically, along the distal portion 102 of the tube 24, the frame 34 is disposed within the tube. The frame is typically made of a shape memory alloy such as Nitinol. For some applications, the shape memory alloy of the frame is shape set such that the frame (and thereby the tube) generally assumes a circular, oval, or polygonal cross-sectional shape when no forces are applied to the tube. By generally assuming a circular, oval, or polygonal cross-sectional shape, the frame is configured to hold the distal portion of the tube in an open state. Typically, during operation of the ventricular assist device, the distal portion of the tube is configured to be placed within the body of the subject such that the distal portion of the tube is at least partially disposed within the left ventricle.

[0159] For some applications (not shown), during operation of the ventricular assist device, the distal portion of the tube is disposed at least partially within the native aortic valve, and the frame is configured to hold the aortic valve open by assuming its generally circular, elliptical, or polygonal cross-sectional shape. For some applications, the tube 24 is sized such that the shape memory alloy of the frame 34 is prevented from fully assuming the dimensions in which the shape memory alloy is shape set. Thus, the frame is "pretensioned" such that the frame will not be radially compressed even when the aortic valve applies a radially compressive force to the tube and the frame. The reason is that the frame is already maintained in a state of being partially radially constrained by the tube. For some applications, the frame includes a plurality of rigid struts 111, and the plurality of rigid struts 111 are disposed parallel to each other and parallel to the longitudinal axis of the frame. The rigid struts are configured such that at least a portion 110 of the frame (along which the struts are disposed) maintains a substantially straight longitudinal axis even when receiving anatomical forces within the left ventricle and / or aortic valve. Typically, the frame 34 changes from a radially constrained configuration (the frame is typically disposed in a radially constrained configuration during introduction of the frame into the subject's body) to a non-radially constrained configuration (the frame is typically disposed in a non-radially constrained configuration during operation of the ventricular assist device) The rigid struts are configured such that the length of the rigid struts does not change even when this occurs.

[0160] For some applications, along the proximal portion 106 of the tube 24, the frame is not disposed within the tube and thus the tube is not supported in an open state by the frame 34. The tube 24 is typically made of a blood-impermeable collapsible material. For example, the tube 24 can include polyurethane, polyester, and / or silicone. Typically, the proximal portion of the 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 tube traverses the aortic valve of the subject and extends from the left ventricle of the subject into the ascending aorta of the subject, as shown in FIG. 1B. As described above, the tube typically defines one or more blood inlet openings 108 at the distal end of the tube, and during operation of the impeller, blood flows from the left ventricle into the tube through the blood inlet openings 108. For some applications, the proximal portion of the tube defines one or more blood outlet openings 109, and during operation of the impeller, blood flows from the tube into the ascending aorta through the blood outlet openings 109. Typically, the tube defines a plurality of blood outlet openings 109, for example, between two and eight blood outlet openings (e.g., between two and four blood outlet openings). During operation of the impeller, the pressure of the blood flow through the tube typically maintains the proximal portion of the tube in an open state. For some applications, for example, in response to the pressure outside the proximal portion of the tube exceeding the pressure inside the proximal portion of the tube when the impeller fails, the proximal portion of the tube is configured to collapse inwardly. Thus, the proximal portion of the tube acts as a safety valve to prevent retrograde blood flow from the aorta into the left ventricle.

[0161] For some applications, the computer processor 25 of the control console 21 (shown in FIG. 1A) is configured to control the pumping of the blood pump (e.g., by controlling the rotation of the impeller) such that the blood pressure generated by the pump in the tube 24 exceeds the systolic aortic pressure of the subject during systole, but is less than the diastolic aortic pressure of the subject during diastole. During systole, the proximal portion 106 of the tube 24 is held open. This is because the blood pressure in the tube exceeds the aortic pressure exerted on the tube from the outside of the tube. During diastole, the proximal portion of the tube 24 closes. This is because the aortic pressure exerted on the tube from the outside of the tube exceeds the blood pressure in the tube. Thus, the impeller pumps blood from the left ventricle to the aorta in a pulsatile manner (i.e., by pumping blood from the left ventricle to the aorta only during diastole). For some applications, the computer processor is configured to measure the aortic pressure, left ventricular pressure, and / or flow through the tube 24 using techniques such as those described hereinafter with reference to FIGS. 9, 16A-16D, and / or FIG. 17. For some such applications, based on the measured aortic pressure, left ventricular pressure, and / or flow, the computer processor controls the rotation of the impeller in the manner described above. Alternatively, the computer processor controls the rotation of the impeller based on the measured aortic pressure, left ventricular pressure, and / or flow in a manner different from the manner described above. For example, the computer processor may be configured to vary the rotational speed of the impeller based on the measured aortic pressure, left ventricular pressure, and / or flow, but such that the impeller pumps blood from the left ventricle to the aorta in a non-pulsatile continuous manner as a result.

[0162] Typically, pumping of blood by the impeller increases the aortic pressure and the left ventricular pressure To reduce. When the flow through the tube 24 reaches the critical value (above the critical value, even during ventricular systole (hereinafter referred to as "cardiac systole"), the aortic pressure is higher than the left ventricular pressure), the aortic valve remains closed around the outside of the tube 24 throughout the cardiac cycle, and the flow from the ventricle to the aorta occurs exclusively through the tube. Typically, above this point where the ventricular pressure is disconnected from the aortic pressure, the left ventricle no longer performs net external work (defined as volume change × pressure change) because it is not moving any volume. In this mode, the oxygen consumption by the left ventricle depends on the periodic pressure generation against the closed aortic valve, the wall tension resulting from the size of the left ventricle, the wall thickness, and the baseline metabolic requirements (including calcium cycling). Below this critical point of impeller activity, the aortic valve is typically at least partially open during cardiac systole, and left ventricular outflow occurs both between the outside of the tube and the aortic valve (due to left ventricular contraction) and through the tube (due to impeller rotation and pumping). For a given impeller revolutions per minute, the larger the cross-sectional area of the sleeve, the larger the flow through the tube will typically be. At the same time, the larger the cross-sectional area of the tube, the more space the tube occupies within the left ventricular outflow tract, the smaller the remaining outflow area, and as a result, the left ventricle must overcome a higher outflow resistance for pumping around the outside of the tube.

[0163] Thus, typically, there is a trade-off between the efficiency of the impeller when assisting the left ventricle (which preferably increases with tube diameter) and the residual resistance to outflow around the outside of tube 24 (which undesirably increases with tube diameter). The higher the flow through the tube provided by the impeller (for a given tube diameter), the more likely it is that the effect of the reduced cross-sectional outflow area on the effective outflow resistance becomes less of an issue, because the remaining cross-sectional area may be appropriate for the small remaining stroke volume that the ventricle has to eject, i.e., the reduced residual outflow path area may not result in an excessive resistance to outflow. Conversely, however, if a fixed tube diameter is selected, as the flow through the tube decreases, the effective resistance to outflow increases. This is because here a larger proportion of the left ventricular stroke volume needs to pass through the residual outflow path area around the tube. Thus, for some applications, the left ventricular outflow resistance is configured to automatically adjust and compensate for changes in the blood flow through the tube generated by the impeller. For example, the tube can be made of a flexible material, and its flexibility is such that a decrease in the flow through the tube and the subsequent drop in expansion pressure results in a decrease in the sleeve diameter, thereby increasing the outflow area available to the left ventricle. Typically, the material properties of the flexible material are defined such that (a) maximum tube expansion is reached at or near the point when the luminal pressure generated by the pump flow exceeds the aortic pressure (regardless of the point in the cardiac cycle), and thus remains above the left ventricular pressure throughout the cardiac cycle, and (b) the tube reaches a fully collapsed state when the flow through the tube generated by the impeller becomes zero.

[0164] Referring now to FIG. 2B, for some applications, a plurality of elongate commissural elements 107 extend at least somewhat along the proximal portion 106 of the tube 24. As described above, for some applications, the computer processor 25 is configured to drive the impeller 50 to pump blood from the left ventricle to the aorta in a pulsatile manner. For some applications, the commissural elements are configured to facilitate opening and closing of the proximal portion of the tube in a manner similar to the opening and closing of natural valve leaflets, such that respective portions of the circumferential portion of the tube form cusps that contact each other when the tube is closed. For some applications, the ventricular assist device includes three elongate commissural elements, and the proximal portion of the tube 24 is configured to close in a manner similar to that of a tricuspid valve. (FIG. 2B shows such an embodiment, although one of the commissural elements is hidden from view.) For some applications (not shown), the ventricular assist device includes two elongate commissural elements, and the proximal portion of the tube 24 is configured to close in a manner similar to that of a mitral valve. For some applications, the proximal portion of the tube 24 is positioned to traverse the aortic valve of the subject, and the commissural elements are aligned in the rotational direction with the commissures of the natural valve. Thus, the artificial cusps of the proximal portion of the tube are aligned with the natural aortic valve leaflets.

[0165] Referring to FIGS. 2A - 2C, for some applications, the frame 34 is shaped to define 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, the tube 24 extends to the end of the cylindrical portion 38, and the distal end of the tube defines a single axially facing blood inlet opening 108 as shown in FIGS. 2A and 2B. Alternatively, the tube 24 extends to the end of the distal conical portion 40, and the tube defines one or more lateral blood inlet openings as shown in FIG. 2C. For such applications, the tube typically defines two to four lateral blood inlet openings.

[0166] Typically, the tube 24 includes a conical proximal portion 42 and a cylindrical central portion 44. The proximal conical portion is typically such that the narrow end of the cone is proximal to the wide end of the cone. As described above, for some applications, the tube extends to the end of the distal conical portion 40 of the frame 34. For such applications, the tube typically defines a distal conical portion 46, with the narrow end of the cone being distal to the wide end of the cone as shown in FIG. 2C. For some applications (not shown), the diameter of the tube 24 varies along the length of the central portion of the tube, such that the central portion of the tube has a frustoconical shape. For example, the central portion of the tube can widen from its proximal end to its distal end, or can narrow from its proximal end to its distal end. For some applications, at its proximal end, the central portion of the tube has a diameter between 5 mm and 7 mm, and at its distal end, the central portion of the tube has a diameter between 8 mm and 12 mm.

[0167] Here, FIGS. 3A-3C are referred to, and FIGS. 3A-3C are schematic explanatory views of the impeller 50 according to some application examples of the present invention. Typically, the impeller includes at least one outer helical elongated element 52, and the helical elongated element 52 is wound around a central axial spring 54 such that the helix defined by the helical elongated element is coaxial with the central axial spring. Typically, the impeller includes two or more helical elongated elements (for example, three helical elongated elements as shown in FIGS. 3A-3C). For some application examples, the helical elongated element and the central axial spring are made of a shape memory material, such as a shape memory alloy like nitinol. Typically, each of the helical elongated element and the central axial spring supports a film 56 of a certain material (for example, a polymer, such as polyurethane and / or silicone, etc.) therebetween. For illustrative purposes, the impeller is shown in FIG. 3A in a state without its material. FIGS. 3B and 3C show respective views of the impeller in a state where a material is supported between the helical elongated element and the spring.

[0168] Each of the helical elongated elements, together with a film extending from the helical elongated element to the spring, defines a respective impeller blade, with the helical elongated element defining the outer edge of the blade and the axial spring defining the axis of the impeller. Typically, the film of the material extends along and covers the spring. For some applications, a suture 53 (e.g., the polyester suture shown in FIGS. 3B and 3C) is wound around the helical elongated element, as described, for example, in U.S. Patent Application Publication No. 2016 / 0022890 by Schwammenthal, which is incorporated herein by reference. Typically, the suture is configured to facilitate the bond between the film of the material (which is typically a polymer, such as polyurethane or silicone, etc.) and the helical elongated element (which is typically a shape memory alloy, such as nitinol, etc.). For some applications, a suture (e.g., a polyester suture (not shown)) is wound around the spring 54. Typically, the suture is configured to facilitate the bond between the film of the material (which is typically a polymer, such as polyurethane or silicone, etc.) and the spring (which is typically a shape memory alloy, such as nitinol, etc.).

[0169] Typically, the proximal ends of the spring 54 and the helical elongated element 52 extend from the proximal bushing (i.e., sleeve bearing) 64 of the impeller, and the proximal ends of the spring 54 and the helical elongated element 52 are arranged at similar radial distances from the longitudinal axis of the impeller. Similarly, typically, the distal ends of the spring 54 and the helical elongated element 52 extend from the distal bushing 58 of the impeller, and the distal ends of the spring 54 and the helical elongated element 52 are arranged at similar radial distances from the longitudinal axis of the impeller. Typically, the spring 54, as well as the proximal bushing 64 and the distal bushing 58 of the impeller, define a lumen 62 therethrough.

[0170] Reference is now made to FIG. 4, which is a schematic illustration of an impeller 50 disposed inside the frame 34 of the ventricular assist device 20 according to some applications of the present invention. As shown, typically, even at the location where the span of the impeller is at its maximum, there is a gap G between the outer edge of the impeller 50 and the inner surface of the frame 34. For some applications, it is desirable that the gap between the outer edge of the impeller blade and the inner surface of the frame 34 be relatively small, such that the impeller is able to efficiently 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 blade and the inner surface of the frame 34 can be maintained, for example, to reduce the risk of hemolysis.

[0171] For some applications, the gap G between the outer edge of the impeller and the inner surface of the frame 34 at the location where the span of the impeller is at its maximum is greater than 0.05 mm (e.g., greater than 0.1 mm), and / or less than 1 mm (e.g., less than 0.4 mm), for example, 0.05 mm to 1 mm, or 0.1 mm to 0.4 mm. For some applications, the outer diameter of the impeller at the location where the outer diameter of the impeller is at its maximum is greater than 6 mm (e.g., greater than 6.5 mm), and / or less than 8 mm (e.g., less than 7 mm), for example, 6 to 8 mm, or 6.5 to 7 mm. For some applications, the inner diameter of the frame 34 is greater than 6.5 mm (e.g., greater than 7 mm), and / or less than 8.5 mm (e.g., less than 7.5 mm), for example, 6.5 to 8.5 mm, or 7 to 7.5 mm.

[0172] Typically, the axial shaft 92 passes through the axis of the impeller 50 through the lumen 62 of the impeller. Typically, the proximal bushing 64 of the impeller is connected to the shaft such that the axial position of the proximal bushing with respect to the shaft is fixed, and the distal bushing 58 of the impeller is slidable with respect to the shaft. The axial shaft itself is radially stabilized via the proximal radial bearing 116 and the distal radial bearing 118 defined by the frame 34. And the axial shaft passes through the lumen 62 defined by the impeller to radially stabilize the impeller with respect to the inner surface of the frame 34, and during rotation of the impeller, even a relatively small gap (e.g., the gap as described above) between the outer edge of the blades of the impeller and the inner surface of the frame 34 is maintained.

[0173] Referring again to FIGS. 3A-3C, for some applications, the impeller includes a plurality of elongated elements 67 that extend radially from a central axial spring 54 to an outer helical elongated element 52. The elongated elements are typically flexible but are substantially inextensible along an axis defined by the elongated elements. Further typically, when no force is acting on the impeller (the force being such as to cause the helical elongated element to move radially outwardly and the separation between the helical elongated element and the central axial spring to be greater than the length of the elongated element in the absence of the elongated element), each of the elongated elements is configured so as not to exert a force on the helical elongated element. For example, the elongated elements can include strings (such as polyester and / or another polymer, or a natural material containing fibers) and / or wires (such as nitinol wire and / or a wire made from a different alloy or metal).

[0174] For some applications, the elongated element 67 maintains a helical elongated element (which defines the outer edge of the impeller blade) within a given distance of the central axial spring. In this way, the elongated element is configured to prevent the outer edge of the impeller from being radially pushed out due to the forces acting on the impeller during rotation of the impeller. The elongated element is thereby configured to maintain a gap between the outer edge of the impeller blade and the inner surface of the frame 34 during rotation of the impeller. Typically, two or more (e.g., three or more), and / or fewer than eight (e.g., fewer than four) elongated elements 67 are used in the impeller, and each of the elongated elements is typically in a doubled state (i.e., extending radially from the central axial spring 54 to the outer helical elongated element 52 and then back from the helical elongated element to the central axial spring). For some applications, a plurality of elongated elements (each of which extends from the spring to its respective helical elongated element and also extends back to the spring) are formed from a single piece of string or a single wire, as will be described in more detail hereinafter.

[0175] For some applications, the impeller is manufactured in the following manner. The proximal bushing 64, the distal bushing 58, and the helical elongated element 52 are cut from a tube of shape memory material such as nitinol. The cutting of the tube and the shape setting of the shape memory material use techniques generally similar to those described, for example, in U.S. Patent Application Publication No. 2016 / 0022890 by Schwammenthal. Typically implemented such that a helical elongated element is defined by a shape memory material. Typically, spring 54 is inserted into a cut and shape set tube such that the spring extends along the length of the tube from at least the proximal bushing to the distal bushing. For some applications, the spring is inserted into the cut and shape set tube while the spring is in an axially compressed state, and the spring is configured to be held in place relative to the tube by applying a radial force to the proximal bushing and the distal bushing. Alternatively or additionally, a portion of the spring is welded to the proximal bushing and the distal bushing. 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 there is substantially no gap between the turns of the spring and the adjacent turns when the spring is disposed in a configuration where it is not radially constrained (during operation of the impeller, the spring is typically disposed in that configuration).

[0176] For some applications, at this stage, the elongate element 67 is arranged to extend between, for example, a spring and one or more of the helical elongate elements as described above in the following manner. A mandrel (e.g., a polyetheretherketone (PEEK) and / or polytetrafluoroethylene (PTFE) mandrel) is inserted through the lumen defined by the spring and the bushing. Then, a string or wire is passed (a) from the mandrel to a first one of the helical elongate elements, (b) back from the first one of the helical elongate elements to the mandrel, (c) around the mandrel and to a second one of the helical elongate elements, (d) back from the second one of the helical elongate elements to the mandrel, etc. When the string or wire is passed from the mandrel to each of the helical elongate elements and back again, the ends of the string or wire are joined together, for example, by tying them to each other. For some applications, a suture 53 (e.g., a polyester suture) is wound around the helical elongate element and is adapted to facilitate the bonding between the film of its material (which is typically a polymer such as polyurethane or silicone, etc.) and the helical elongate element (which is typically a shape memory alloy such as nitinol, etc.) in a subsequent stage of the impeller manufacture. For some applications, a suture (e.g., a polyester suture (not shown)) is wound around the spring 54. Typically, the suture is configured to facilitate the bonding between the film of its material (which is typically a polymer such as polyurethane or silicone, etc.) and the spring (which is typically a shape memory alloy such as nitinol, etc.) in a subsequent stage of the impeller manufacture.

[0177] Typically, at this stage, a structure 59 as shown in FIG. 3A is assembled. The structure includes a cut and shaped tube that defines a proximal bushing, a distal bushing, and a helical elongated element, a spring, optionally, an elongated element, and a suture thread. This structure is immersed into a material that defines film 56. For some applications, it is noted that the assembled structure is immersed into the material with a mandrel disposed through the lumen defined by the spring and the bushing, although the mandrel is not shown in FIG. 3A. Typically, the material from which the film is made is silicone (and / or a similar polymer), and the assembled structure is immersed into the material while the material is in an uncured liquid state. Thereafter, the material is cured, for example, by being left to dry so that the material solidifies. When the material dries, the mandrel is typically removed from the lumen defined by the bushing and the spring.

[0178] The result of the process described above is typically that there is a continuous film of material, the continuous film of material extending to the spring between each of the helical elongated elements, also extending along the length of the spring, being configured to define a tube, with the spring being embedded within the tube. The portion of the film extending from each of the helical elongated elements to the spring defines an impeller blade. For applications where the impeller includes an elongated element 67, the elongated element is typically embedded within these portions of the film.

[0179] Typically, impeller 50 is inserted transcatheterically into the left ventricle with the impeller 50 in a radially constrained configuration. In the radially constrained configuration, both the helical elongate element 52 and the central axial spring 54 are axially elongate and radially constrained. Typically, a film 56 of material (e.g., silicone) changes shape to conform to the shape changes of the helical elongate element and the axial support spring, both of which support the film of material. Typically, using a spring to support the inner edge of the film allows the film to change shape without being torn or crushed due to the large surface area provided by the spring to which the inner edge of the film attaches. For some applications, using a spring to support the inner edge of the film reduces the diameter at which the impeller can be radially constrained, for example, as compared to the case where a rigid shaft is used to support the inner edge of the film. The reason is that the diameter of the spring itself can be reduced by making the spring axially elongate.

[0180] As described above, for some applications, the proximal bushing 64 of impeller 50 is connected 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, for the purpose of inserting the impeller into the ventricle or withdrawing the impeller from the subject's body, when the impeller is radially constrained, the impeller elongates axially as the distal bushing slides distally along the axial shaft.

[0181] Subsequent to being released inside the subject's body, the impeller assumes a configuration that is not radially constrained, as shown in FIGS. 3A-3C (during operation of the impeller, the impeller is typically disposed in that configuration). Typically, each pitch of the helical elongated element 52 is greater than 1 mm (e.g., greater than 6 mm) and / or less than 20 mm (e.g., less than 10 mm) when the impeller 50 is in a configuration that is not radially constrained (e.g., inside the subject's ventricle). Typically, all other conditions being equal, the greater the pitch of the helical elongated element (and thus the impeller blade), the greater the blood flow generated by the impeller. Thus, as described, when the impeller 50 is in a configuration that is not radially constrained, the pitch of the helical elongated element 52 is typically greater than 1 mm (e.g., greater than 6 mm). On the other hand, it is typically desirable for the impeller to occlude retrograde blood flow into the subject's left ventricle. Typically, all other conditions being equal, the smaller the pitch of the helical elongated element (and thus the impeller blade), the greater the occlusion provided by the impeller. Thus , as described, when the impeller 50 is in a configuration that is not radially constrained, the pitch of the helical elongated element 52 is typically less than 20 mm (e.g., less than 10 mm).

[0182] For some applications, the pitch of the helical elongated element (and thus the impeller blade) varies along the length of the helical elongated element, at least when the impeller is configured such that it is not radially constrained. Typically, for such applications, the pitch increases from the distal end of the impeller (i.e., the end that is inserted further into the subject's body and is upstream with respect to the direction of antegrade blood flow) to the proximal end of the impeller (i.e., the end that is downstream with respect to the direction of antegrade blood flow), such that the pitch increases in the direction of blood flow. Typically, the blood flow rate increases along the direction of blood flow along the impeller. Thus, the pitch is increased along the direction of blood flow so as to further accelerate the blood.

[0183] For purposes of illustration, it is noted that in some of the figures, the impeller 50 is shown without including all of the features of the impeller as shown and described with reference to FIGS. 3A-3C. For example, some of the figures show impellers that do not include the suture 53 and / or the elongated element 67. The scope of the present application includes using an impeller having any of the features shown and described with reference to FIGS. 3A-3C in combination with any of the devices and methods described herein.

[0184] Reference is now made to FIGS. 5A and 5B, which are schematic illustrations of an impeller 50 and a frame 34 of a ventricular assist device 20 in an unconstrained state and a radially constrained state, respectively, according to some applications of the present invention. The impeller and the frame are typically disposed in a radially constrained state during percutaneous insertion of the impeller and the frame into the body of the subject, and are disposed in an unconstrained state during operation of the impeller inside the left ventricle of the subject. As described above, typically the tube 24 extends at least from and proximally from the distal portion of the frame. However, for illustrative purposes, the frame and the impeller are shown in FIGS. 5A-5B without the tube 24 present. As shown in FIG. 5B, the frame and the impeller are typically maintained in a radially constrained configuration by a delivery catheter 143.

[0185] Also, reference is made to FIG. 5C, which shows a typical bearing assembly used in prior art axial impeller-based blood pumps. FIG. 5C is shown for the purpose of acting as a reference point with respect to some of the application examples of the present invention described herein. As shown in FIG. 5C, the bearing assembly typically includes a radial bearing (shown by ellipse 200) and a thrust bearing (shown by circle 202). The radial bearing is configured to reduce the radial movement of the impeller by maintaining the axis of the impeller at a given radial position. In response to the impeller pumping blood in a first direction, the force acting on the impeller typically pushes the impeller to move in a direction opposite to the first direction. The purpose of the thrust bearing is to counteract such movement of the impeller and also to maintain the axial position of the impeller. In the example shown in FIG. 5C, in response to the impeller pumping blood in the direction of arrow 204, the impeller is pushed in the direction of arrow 206 and the thrust bearing counteracts this movement. Typically, due to the frictional forces acting on them, the bearings experience a significant amount of heating and wear. The fact that the frictional force acting on the thrust bearing is typically spread over the opposing surfaces having a contact area between them causes the thrust bearing to typically be exposed to significant heating and wear. Due to the fact that they are spread over opposing surfaces having a contact area between them, thrust bearings are typically exposed to significant heating and wear.

[0186] As described above, typically, the axial shaft 92 passes through the axis of the impeller 50 via the lumen 62 of the impeller. 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 with respect to the shaft is fixed, and the distal bushing 58 of the impeller is slidable with respect to the shaft. The axial shaft itself is radially stabilized via a proximal radial bearing 116 and a distal radial bearing 118 defined by the frame 34. And the axial shaft passes through the lumen 62 defined by the impeller to radially stabilize the impeller with respect to the inner surface of the frame 34, and as described above, during rotation of the impeller, even a relatively small gap (e.g., a gap as described above) between the outer edge of the impeller blade and the inner surface of the frame 34 is maintained. For some applications, the axial shaft 92 is made of stainless steel, and the proximal bearing 116 and / or the distal bearing 118 are made of hardened steel. Typically, for the purpose of inserting the impeller and the frame into the body of a subject, when the impeller and the frame are crimped (i.e., radially constrained), the distal bushing 58 of the impeller is configured to slide distally along the axial shaft, and as described above, the impeller is axially elongated. More generally, the impeller changes from its radially constrained configuration to its non-radially constrained configuration by the distal bushing sliding over the axial shaft, and vice versa.

[0187] Typically, the impeller itself is not disposed directly within any radial or thrust bearing. Rather, bearings 116 and 118 act as radial bearings with respect to the axial shaft. For some applications, there is no thrust bearing in contact with any surface that can generate a thrust force during rotation of the impeller. The reason is that, as will be explained in more detail hereinafter, the impeller is configured to move axially within the frame 34 while the impeller is rotating. Typically, the pump portion 27 (and, more generally, the ventricular assist device 20) is configured to be disposed within the body of the subject and does not include any thrust bearing configured to counteract the thrust generated by the rotation of the impeller. For some applications, one or more thrust bearings are disposed outside the body of the subject (e.g., within the motor unit 23 shown in FIGS. 1A, 7, and 8A - 8B), and the counteraction to the thrust generated by the rotation of the impeller is provided only by one or more thrust bearings disposed outside the body of the subject. For some applications, mechanical and / or magnetic elements are configured to maintain the impeller within a given range of axial position. For example, a magnet (e.g., magnet 82 described hereinafter with reference to FIG. 7) disposed at the proximal end of a drive cable (e.g., outside the body of the subject) can be configured to impart axial movement to the impeller and can also be configured to maintain the impeller within a given range of axial position.

[0188] For some alternative applications of the present invention, the ventricular assist device includes an impeller that is not configured to move in an axial reciprocating motion. For some such applications (not shown), a thrust bearing is used to maintain the axial position of the impeller, and the thrust bearing is disposed within a portion of the ventricular assist device proximal to the impeller such that the thrust bearing is prevented from contacting the subject's blood. For example, a thrust bearing may be disposed within the outer tube, and within the outer tube, a drive shaft of the impeller is disposed. Alternatively or additionally, the thrust bearing may be disposed outside the subject's body. For some such applications, since the thrust bearing is disposed outside the subject's body, the dimensions of the thrust bearing are not subject to the constraints resulting from having to be deployed within a small anatomical location. Thus, in such cases, the contact area between two opposing surfaces of the thrust bearing is typically greater than 20 square millimeters. For some applications (not shown), the thrust bearing is disposed in contact with the subject's blood distal to the impeller, and the thrust bearing is cooled by the subject's blood.

[0189] Reference is now made to FIGS. 6A and 6B, which are schematic illustrations of a ventricular assist device 20 at respective stages of a movement cycle of an impeller 50 of the ventricular assist device with respect to a frame 34 of the ventricular assist device, according to some applications of the present invention. For some applications, while the impeller is pumping blood through the tube 24 by rotating, the axial shaft 92 (to which the impeller is fixed) is driven to move the impeller axially back and forth within the frame 34 by the axial shaft moving in an axial forward and backward movement, as will be described in more detail hereinafter with reference to FIG. 7. Alternatively or additionally, the impeller and the axial shaft are configured to move axially back and forth within the frame 34 without the need to be actively driven, for example, in response to forces acting on the impeller and for the axial shaft to move in an axial forward and backward movement, as will be described in more detail hereinafter with reference to FIG. 9.

[0190] For some applications, by moving in a reciprocating motion, the portion of the axial shaft that contacts the proximal bearing 116 and the distal bearing 118 is constantly changing. For some such applications, thus, the frictional force exerted on the axial shaft by the bearings is spread over a larger area of the axial shaft than if the axial shaft did not move relative to the bearings, thereby reducing wear on the axial shaft if other conditions are equal. Alternatively or additionally, by moving in a reciprocating motion relative to the bearings, the axial shaft cleans the interface between the axial shaft and the bearings from any residue such as blood residue.

[0191] For some applications, when the frame 34 and the impeller 50 are configured such that they are not radially constrained (e.g., when the frame and the 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 bearing 116 and the distal bearing 118 each have a length of 2 - 4 mm. More typically, the impeller and the axial shaft are configured to move axially through the frame in a reciprocating motion along at least the respective lengths of the proximal and distal bearings, or at least twice the respective lengths of the bearings. Thus, during the axial reciprocating movement of the axial shaft, the axial shaft is wiped clean on either side of each of the bearings.

[0192] Again, reference is made to FIGS. 6A and 6B, and also to FIG. 6C, which is a schematic illustration of the axial shaft receiving tube 126 and the distal tip portion 120 of the ventricular assist device 20 according to some applications of the present invention. For some applications, the distal tip portion of the ventricular assist device is configured to be soft and is configured such that even when the distal tip portion contacts tissue (e.g., the tissue of the left ventricle), the distal tip portion does not damage the subject's tissue. For example, the distal tip portion can be made of silicone. For some applications, the distal tip portion defines a lumen 122 therethrough. For some such applications, during insertion of the ventricular assist device into the left ventricle, the guide wire 10 (FIG. 1B) is first inserted into the left ventricle, for example, according to known techniques. Then, with the guide wire disposed inside the lumen 122, the distal tip portion of the ventricular assist device is guided into the left ventricle by advancing the distal tip portion over the guide wire. For some applications, a hemostatic valve 152 is disposed at the distal end of the lumen 122 of the distal tip portion 120, and after the guide wire is retracted from the lumen 122, the distal tip portion is sealed. Typically, during insertion of the ventricular assist device into the subject's ventricle, the delivery catheter 143 is placed over the impeller 50 and the frame 34 and maintains the impeller and the frame in their radially constrained configuration. For some applications, the distal tip portion 120 extends distally from the delivery catheter during insertion of the delivery catheter into the subject's ventricle. For some applications, at the proximal end of the distal tip portion, the distal tip portion has a flared portion 124, and the flared portion 124 acts as a stopper to prevent the delivery catheter from advancing beyond the flared portion. For some applications, the distal tip portion defines a lumen 122 therethrough. For some such applications, during insertion of the ventricular assist device into the left ventricle, the guide wire 10 (FIG. 1B) is first inserted into the left ventricle, for example, according to known techniques. Then, with the guide wire disposed inside the lumen 122, the distal tip portion of the ventricular assist device is guided into the left ventricle by advancing the distal tip portion over the guide wire. For some applications, a hemostatic valve 152 is disposed at the distal end of the lumen 122 of the distal tip portion 120, and after the guide wire is retracted from the lumen 122, the distal tip portion is sealed. Typically, during insertion of the ventricular assist device into the subject's ventricle, the delivery catheter 143 is placed over the impeller 50 and the frame 34 and maintains the impeller and the frame in their radially constrained configuration. For some applications, the distal tip portion 120 extends distally from the delivery catheter during insertion of the delivery catheter into the subject's ventricle. For some applications, at the proximal end of the distal tip portion, the distal tip portion has a flared portion 124, and the flared portion 124 acts as a stopper to prevent the delivery catheter from advancing beyond the flared portion.

[0193] For some applications, the axially shaft receiving tube 126 extends proximally from the distal tip portion 120. As described above, typically, the axially shaft experiences an axial forward and backward movement during the operation of the impeller 50. The shaft receiving tube 126 defines a lumen 127, and the lumen 127 is configured to receive the axially shaft when the axially shaft extends beyond the distal bearing 118. For some applications, the shaft receiving tube defines a stopper 128 at its distal end, and the stopper is configured to prevent the forward movement of the axially shaft beyond the stopper. For some applications, the stopper includes a rigid component that is inserted (e.g., embedded) into the distal end of the shaft receiving tube. Alternatively, the stopper includes a shoulder portion between the lumen 127 of the axially shaft receiving tube and the lumen 122 of the tip portion 120. Typically, such a shoulder portion exists because the lumen 122 of the tip portion 120 is narrower than the lumen 127. (This is because the lumen 127 is typically configured to accommodate the axially shaft, while the lumen 122 is configured to accommodate the guide wire 10, and the axially shaft itself is configured to accommodate the guide wire 10 in the internal lumen 132 of the axially shaft (shown in FIGS. 10B and 10C), so the axially shaft is typically wider than the guide wire 10.) Typically, during the normal operation of the impeller, the axially shaft does not extend to the stopper 128 even when the drive cable 130 (shown in FIG. 7) is fully extended. However, the stopper 128 is configured to prevent the axially shaft from protruding into the tip portion when the delivery catheter is advanced over the impeller 50 and the frame 34 during the retraction of the ventricular assist device 20 from the ventricle of the subject. In some cases, during the advancement of the delivery catheter over the frame and the impeller, the drive cable is at risk of snapping.In the case where the stopper 128 is absent, in such a case, the axial shaft may protrude into the tip portion. The stopper 128 prevents this from occurring even when the drive cable snaps.

[0194] Typically, during operation of the ventricular assist device and throughout the entire axial motion cycle of the forward and backward movement of the impeller, the impeller is disposed relatively extremely proximally to the distal tip portion. For example, the distance of the impeller to the distal tip portion can be within the most distal 50 percent, for example, the most distal 30 percent (or the most distal 20 percent) of the tube 24 throughout the entire cycle of the axial motion of the forward and backward movement of the impeller.

[0195] For some applications (not shown), a portion of the frame 34 extends into the proximal portion of the distal tip portion 120. A portion of the frame is configured such that by shape-setting the portion of the frame to have a radially expanded configuration, the proximal portion of the tip experiences a radial expansion when the proximal portion of the tip is deployed into the left ventricle of the subject. For some applications, the entire tip portion is made of a material having uniform rigidity, but a portion of the frame 34 that extends into the proximal portion of the tip portion imparts rigidity to the proximal portion of the tip portion, such that the proximal portion of the tip portion has greater rigidity than the distal portion of the tip portion.

[0196] For some applications, the distal tip portion has a configuration different from that shown in FIG. 6C, as will be described in more detail hereinafter with reference to FIGS. 18-24B, for example. For some applications, the distal tip portion combines certain features described in connection with FIG. 6C with features described hereinafter in connection with FIGS. 13 and 18-24B, for example. For example, the internal structure of the tip portion and the proximal extension of the axial shaft receiving tube 126 from the tip portion can be as described with reference to FIGS. 6 and / or 13, and the external shape of the tip portion can be as described with reference to any one of FIGS. 18-24B.

[0197] Reference is now made to FIG. 7, which is a schematic illustration of an exploded view of the motor unit 23 of the ventricular assist device 20 according to some applications of the present invention. For some applications, the computer processor 25 (FIG. 1A) of the control console 21 that controls the rotation of the impeller 50 is also configured to control the forward and backward movement of the axial shaft. Typically, both types of movement are generated using the motor unit 23. The scope of the present invention includes controlling the forward and backward movement at any frequency. For some applications, an indication of the subject's cardiac cycle is detected (e.g., by detecting the subject's ECG), and the forward and backward movement of the axial shaft is synchronized with the subject's cardiac cycle.

[0198] Typically, the motor unit 23 includes a motor 74, which is configured to impart rotational movement to the impeller 50 via a drive cable 130. As will be described in more detail hereinafter, typically, the motor is magnetically coupled to the drive cable. For some applications, an axial motion driver 76 is configured to drive the motor to move in an axial forward and backward motion as indicated by the double arrows 79. Typically, due to the magnetic coupling of the motor to the drive cable, the motor imparts the forward and backward motion to the drive cable, and it imparts this motion to the impeller. As will be described hereinafter, for some applications, the drive cable, the impeller, and / or the axial shaft may experience axial forward and backward motion in a passive manner, for example, due to periodic changes in the pressure gradient against which the impeller pumps blood. Typically, for such applications, the motor unit 23 does not include an axial motion driver 76.

[0199] For some applications, the magnetic coupling of the motor to the drive cable is as shown in FIG. 7. As shown in FIG. 7, a set of drive magnets 77 are coupled to the motor via a drive magnet housing 78. For some applications, the drive magnet housing includes a ring 81 (e.g., a steel ring), and the drive magnets are adhered to the inner surface of the ring. For some applications, a spacer 85 is adhered to the inner surface of the ring 81 between two of the drive magnets as shown. A driven magnet 82 is disposed between the drive magnets and has an axial overlap The plunger is configured to be present between the drive magnet and the driven magnet, and the driven magnet 82 is coupled to the proximal end of the drive cable 130. For example, the driven magnet can be cylindrical and can define a bore therethrough, and the proximal end of the drive cable can be adhered to the inner surface of the driven magnet that defines the bore. For some applications, the driven magnet is cylindrical, the magnet includes an N pole and an S pole, and the N pole and the S pole are separated from each other along the length of the cylinder along a line 83 that bisects the cylinder as shown. For some applications, the driven magnet is housed inside a cylindrical housing 87.

[0200] Magnetic couplings are most powerful when the magnetic field density is maximized. Thus, it is desirable to use relatively powerful magnets for the drive magnet and the driven magnet, have a small air gap between the drive magnet and the driven magnet, and attempt to minimize magnetic flux leakage. Typically, the drive magnet and the driven magnet are neodymium magnets, which are relatively powerful. More typically, the gap between each of the drive magnets and the driven magnet is less than 2 mm, for example, approximately 1 mm. To reduce magnetic flux leakage, typically fewer than four magnets (for example, exactly two magnets as shown) are used as the drive magnets for the following reasons.

[0201] Typically, for example, it is desirable to minimize the diameter of the driven magnet in order to stabilize the driven magnet. As described above, the driven magnet is in a cylindrical shape, and the magnet includes an N pole and an S pole, and the N pole and the S pole are divided from each other along the length of the cylinder along the dividing line 83. In the region of the peripheral portion of the driven magnet closest to the dividing line between the N pole and the S pole of the magnet, the magnetic field lines pass through the air gap to the first outer magnet, pass through the outer magnet, go around the ring 81, cross the second drive magnet, and rather than returning to the S pole of the driven magnet, directly pass from the N pole to the S pole of the magnet. As an approximation, any magnetic field line that can be drawn between the N pole and the S pole (the length of which is less than at least the total of the air gaps between the driven magnet and the drive magnet) will pass from the N pole of the driven magnet to the S pole of the driven magnet rather than taking an alternative route. Assuming that this results in all magnetic field lines extending around the 2 mm of the peripheral portion of the driven magnet on either side of the dividing line between the N pole and the S pole of the driven magnet, it is a total of 4 mm of the total peripheral portion of the driven magnet that does not contribute to the magnetic coupling between the drive magnet and the driven magnet. If, instead of simply two poles, the driven magnet had four poles and correspondingly there were four drive magnets, there would be four occurrences of a 2 mm long wasted peripheral section throughout the peripheral portion, which would result in a total of 8 mm out of the 12 mm of the peripheral portion of the inner magnet with wasted magnetic field lines. Some of this loss will be compensated for by the addition of two additional drive magnets, which increases the magnetic field strength. However, the additional outer magnets will be relatively close to each other, which will result in a magnetic field leaking between the drive magnets. Considering the above, typically, the motor unit includes fewer than four magnets as drive magnets (for example, exactly two magnets as shown), and the driven magnet is divided into fewer than four poles (for example, exactly two poles as shown).

[0202] In the application example shown in FIG. 7, it is noted that the drive magnet is disposed outside the driven magnet. However, the scope of the present application includes changing what should be changed and reversing the configurations of the drive magnet and the driven magnet. For example, the proximal end portion of the drive cable can be connected to two or more driven magnets, the two or more driven magnets are disposed around the drive magnet, and there is an axial overlap between the driven magnet and the drive magnet. The above discussion regarding the number of magnets to be used as the outer magnet and the number of poles into which the inner magnet should be divided is equally applicable to such a configuration. That is, for such a configuration, typically, the motor unit includes fewer than four magnets (e.g., exactly two magnets as shown) as the driven magnet, and the drive magnet is divided into fewer than four poles (e.g., exactly two poles as shown). As described above, typically, a purging system 29 (shown in FIG. 1A) is used with the ventricular assist device 20. Typically, the motor unit 23 includes an inlet port 86 and an outlet port 88 for use with the purging system. For some application examples, the purging fluid is pumped continuously or periodically into the ventricular assist device through the inlet port 86 and out of the ventricular assist device through the outlet port 88. For some application examples, the purging fluid is pumped into the ventricular assist device, the inlet port and the outlet port are installed in fluid communication with each other, and a given volume of purging fluid circulates through the device over a period of time. Additional aspects of the purging system are described hereinafter.

[0203]

[0204] ​Reference is now made to FIGS. 8A and 8B, which are schematic illustrations of motor unit 23 according to some applications of the present invention. Generally, motor unit 23 as shown in FIGS. 8A and 8B is similar to that shown in FIG. 7, and unless otherwise described, motor unit 23 as shown in FIGS. 8A and 8B contains components similar to those of motor unit 23 as shown in FIG. 7. For some applications, the motor unit includes a heat sink 90, which is configured to dissipate heat generated by the motor. Alternatively or additionally, the motor unit includes a ventilation port 93, which is configured to facilitate dissipation of heat generated by the motor. For some applications, the motor unit includes vibration dampers 94 and 96, which are configured to dampen vibrations of the motor unit caused by rotational and / or axial reciprocating motion of components of the ventricular assist device.

[0205] For some applications, the impeller 50 and the axial shaft 92 are configured to move axially back and forth within the frame 34 in response to forces acting on the impeller and without the need to be actively driven such that the axial shaft moves in an axial forward and backward motion. Typically, during the cardiac cycle of a subject, the pressure difference between the left ventricle and the aorta changes from a state where it is approximately zero during ventricular systole (hereinafter “cardiac systole”) to a state of a relatively large pressure difference (e.g., 60 - 100 mmHg) during ventricular diastole (hereinafter “cardiac diastole”). For some applications, due to the increased pressure difference (against which the impeller pumps during cardiac diastole), the impeller is pushed distally relative to the frame 34 during cardiac diastole relative to its location with respect to the frame 34 during cardiac systole. And since the impeller is connected to the axial shaft, the axial shaft is caused to move forward. During cardiac systole, the impeller (and the axial shaft) move back to their systolic positions. Thus, the axial forward and backward motion of the impeller and the axial shaft is generated in a passive manner, i.e., it is generated without the need for active driving of the axial shaft and the impeller to cause the impeller and the axial shaft to experience this motion.

[0206] Reference is now made to FIG. 9, which is a graph showing the variation in the length of the drive cable of a ventricular assist device as the pressure gradient against which the impeller of the ventricular assist device changes, as measured in an experiment conducted by the inventors of the present application. As described herein An impeller and drive cable, as described, are used to pump a glycerin-based solution through a chamber, which is set up to replicate the left ventricle and aorta, and the solution has properties similar to those of blood (e.g., density and viscosity). Due to the increasing volume of fluid disposed within the chamber (into which the impeller pumps), the pressure gradient (against which the impeller pumps) changes. At the same time, the movement of the drive cable is imaged and the change in the length of the drive cable is determined via machine vision analysis of the image. The graph shown in FIG. 9 depicts the change in the length of the drive cable measured as a function of the pressure gradient. The y-axis of the graph shown in FIG. 9 is such that a 0 mm elongation represents the length of the drive cable when the impeller is at rest. It is noted that the graph starts at a pressure gradient value of 65 mmHg and that at this pressure the elongation is negative (approximately -0.25 mm), i.e., the drive cable is shortened relative to the length of the drive cable prior to the start of impeller rotation. This is because the drive cable was configured such that as the impeller first starts pumping, as will be explained in more detail later, the coils within the drive cable unwind, causing the drive cable to shorten (relative to the length of the drive cable before the impeller is activated). As can be seen in the section of the curve shown in FIG. 9, after the initial shortening of the drive cable resulting from the above-described effect, it was in fact the case that as the pressure gradient increased, the drive cable became increasingly elongated.

[0207] As shown by the results shown in FIG. 9, and as described above, typically, in response to fluctuations in pressure (against which the impeller pumps blood), such as the pressure difference between the left ventricle and the aorta, it is a fact that the impeller moves back and forth with respect to the frame 34. And the movement of the impeller causes the drive cable 130 to become more or less elongated.

[0208] For some applications, during operation of the ventricular assist device, the computer processor 25 (FIG. 1A) of the control console 21 is configured to measure an indication of the tension in the drive cable 130 and / or the axial movement of the drive cable, thereby measuring an indication of the pressure exerted on the impeller (which indicates the pressure difference between the left ventricle and the aorta). For some applications, based on the measured indication, the computer processor detects events during the subject's cardiac cycle, determines the subject's left ventricular pressure, and / or determines the afterload of the subject's heart. For some applications, the computer processor controls the rotation of the impeller and / or controls the axial forward and backward movement of the axial shaft in response thereto.

[0209] For some applications, generally similar techniques are applied to a right ventricular assist device configured to pump blood from the right ventricle to the pulmonary artery, and the computer processor is configured to determine the pressure difference between the right ventricle and the pulmonary artery in generally the same manner, with modifications where appropriate. For some applications, generally similar techniques are applied to a cardiac assist device configured to pump blood from a first location to a second location (e.g., from the vena cava to the right ventricle, from the right atrium to the right ventricle, from the vena cava to the pulmonary artery, and / or from the right atrium to the pulmonary artery, etc.), and the computer processor is configured to determine the pressure difference between the first location and the second location in generally the same manner, with modifications where appropriate.

[0210] Referring again to FIG. 7, for some applications, the ventricular assist device 20 includes a sensor 84. For example, the sensor can include a Hall sensor, and the Hall sensor is disposed within the motor unit 23 as shown in FIG. 7. For some applications, to measure the axial movement of the drive cable 130 and to determine the pressure against which the impeller is pumping, the Hall sensor measures the variation in the magnetic field generated by one of the magnets. For example, the inner driven magnet 82 can be axially longer than the outer drive magnet 77. Due to the inner magnet being longer than the outer magnet, there are magnetic field lines emitted from the inner magnet that do not pass through the outer magnet, and the magnetic flux generated by those magnetic field lines changes according to the drive cable as measured by the Hall sensor, and the inner magnet moves axially. During operation, the motor 74 rotates, generating an AC signal in the Hall sensor, which typically has a frequency between 200 Hz and 800 Hz. Typically, when the tension in the drive cable changes due to the subject's cardiac cycle, this produces a low-frequency envelope in the signal measured by the Hall sensor, and the low-frequency envelope typically has a frequency of 0.5 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. It is noted that typically the axial movement of the magnet is substantially less than that of the impeller because not the entire range of impeller movement is transmitted along the length of the drive cable. However, it is true that typically the axial back-and-forth movement of the impeller causes a measurable back-and-forth movement of the magnet.

[0211] For some applications, the Hall sensor measurements are initially calibrated such that the change in magnetic flux per unit change in the pressure against which the impeller pumps (i.e., per unit change in the pressure difference between the left ventricle and the aorta) is known. In most subjects, it is known that during systole, the left ventricular pressure is equal to the aortic pressure. Thus, for some applications, the aortic pressure of the subject is measured and the left ventricular pressure of the subject at a given time is then calculated by a computer processor based on (a) the measured aortic pressure and (b) the difference between the magnetic flux measured by the Hall sensor at that time and the magnetic flux measured by the Hall sensor during systole (when the pressure in the left ventricle is assumed to be equal to the aortic pressure).

[0212] Reference is now made to FIGS. 10A, 10B, and 10C, which are schematic illustrations of the drive cable 130 of the ventricular assist device 20 according to some applications of the present invention. Typically, the rotational movement of the impeller (which is imparted via the axial shaft) and the axial forward and backward movement of the axial shaft as described above are imparted to the axial shaft via the drive cable as described above. 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 (as shown in FIG. 10C. FIG. 10C 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 includes a plurality of wires 134, which are arranged in a tightly coiled configuration to impart sufficient strength and flexibility to the drive cable such that a portion of the cable can be maintained within the aortic arch (the portion corresponding to arrow 145 in FIG. 10A) while the cable rotates and moves with the axial forward and backward movement. The drive cable is typically disposed within a first outer tube 140, which is configured to remain stationary while the drive cable experiences rotational movement and / or axial forward and backward movement. The first outer tube is configured to act effectively as a bearing along the length of the drive cable. Typically, the first outer tube is made of a polymer (e.g., polyetheretherketone, etc.), and the polymer is the drive cable and the first outer Even under the frictional forces generated by relative movement with the tube, it is configured to be highly resistant to fatigue. However, since such polymers are typically relatively rigid, only a thin layer of the polymer is typically used within the first outer tube. For some applications, the first outer tube is disposed within a second outer tube 142, and the second outer tube 142 is made of a material having a greater flexibility than the flexibility of the first outer tube (e.g., nylon and / or polyether block amide), and the thickness of the second outer tube is greater than the thickness of the first outer tube.

[0213] Typically, during insertion of the impeller and cage into the left ventricle, the impeller 50 and the frame 34 are maintained in a radially constrained configuration by the delivery catheter 143. As described above, the delivery catheter is retracted to allow the impeller and frame to assume a non-radially constrained configuration. For some applications, as shown in FIG. 10A, the delivery catheter remains within the subject's aorta during operation of the left ventricular device, and the outer tube 142 is disposed inside the delivery catheter. To retract the left ventricular device from the subject's body, the delivery catheter is advanced over the impeller and frame, causing the impeller and frame to assume their radially constrained configuration. The catheter is then withdrawn from the subject's body.

[0214] Referring to FIG. 10C, typically, the axial shaft and cable define a continuous lumen 132 therethrough. For some applications, the left ventricular device is guided to the aorta and into the left ventricle by placing the axial shaft and cable over the guide wire 10 (described above) such that the guide wire is disposed inside the lumen 132. For some applications, using the lumen of the axial shaft and cable in this manner obviates the need for an additional guide wire guide used during insertion of the left ventricular assist device 20. For some applications, the axial shaft and cable each have an outer diameter greater than 0.6 mm (e.g., greater than 0.8 mm) and / or less than 1.2 mm (e.g., less than 1 mm), such as 0.6-1.2 mm, or 0.8-1 mm. For some applications, the diameter of the lumen 132 defined by the shaft and cable is greater than 0.3 mm (e.g., greater than 0.4 mm) and / or less than 0.7 mm (e.g., less than 0.6 mm), such as 0.3-0.7 mm, or 0.4-0.6 mm. For some applications, the drive cable 130 has a total length 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), such as 1-1.4 m, or 1.1-1.3 m. As described above, for some applications, the guide wire additionally passes through the lumen 122 of the distal tip portion 120. Typically, the diameter of the lumen 122 is generally similar to the diameter of the lumen 132.

[0215] Referring to FIG. 10B, for some applications, the drive cable 130 is composed of a plurality of coiled wires 134. Typically, due to the impeller having to pump against the pressure gradient during diastole, the impeller is pushed distally relative to the frame 34 with respect to the position of the impeller relative to the frame during systole, as described above. The direction of rotation of the impeller is such that if the rotation of the drive cable in this direction results in the coiled wires of the drive cable that are at least partially tightened, this means that the coiled wires are tightened (i.e., wound up such that the radius of the coil decreases) Due to this and thereby, when the rotation of the impeller is started, which is caused by making it elongated in the axial direction, the impeller will also be caused to advance relative to the frame. For some applications, (a) in response to the impeller pumping blood from the left ventricle to the aorta by rotating in a predetermined direction of rotation, (b) the rotation of the drive cable in this direction results in at least a partial unwinding of the coiled wire of the drive cable along a portion of the drive cable, such that at least a portion of the drive cable is configured to shorten in the axial direction. By configuring the drive cable in the manner described above, the length of the frame 34, in addition to accommodating the distal movement of the impeller in the frame resulting from the pressure changes due to the subject's cardiac cycle (as described above), does not need to accommodate the distal movement of the impeller resulting from the drive cable becoming elongated in the axial direction. For some applications, the extent to which the drive cable can unwind and thereby shorten in the axial direction is limited by the outer tube in which the drive cable is disposed, preventing the drive cable from expanding radially. Thus, for some applications, the axial shortening of the drive cable is only a relatively small amount. For some applications, due to the outer tube limiting the extent to which the drive cable can unwind and thereby shorten in the axial direction, the drive cable does not shorten. However, even in such applications, the drive cable is typically configured not to become elongated due to the winding of the coil configured as described above.

[0216] Alternatively or additionally, the impeller is inserted into the frame 34 and the drive cable is already preloaded (i.e., the impeller is adapted to exert tension on the drive cable, which causes the drive cable to elongate axially relative to its rest state). Due to the preloading of the drive cable, when rotation of the impeller is initiated, this does not cause the drive cable to elongate axially. The reason is that the drive cable is already axially elongated relative to its rest state. For some such applications, the impeller is still configured to experience an axial forward and backward movement as a result of pressure changes due to the cardiac cycle of the subject (as described above).

[0217] For some applications, debris is generated by the frictional force between the drive cable and the outer tube 140. Alternatively or additionally, a fluid (e.g., a purging fluid) is disposed between the drive cable and the outer tube. Typically, due to the coiling of the coiled drive cable, the drive cable acts as an impeller and pumps debris and / or fluid axially with respect to the outer tube 140. For some applications, the direction of coiling of the drive cable is such that the drive cable pumps debris and / or fluid towards the proximal end of the ventricular assist device by rotating in a predetermined rotational direction and does not pump debris and / or fluid towards the distal end of the ventricular assist device towards the patient's left ventricle.

[0218] Reference is now made to FIGS. 11A and 11B, which are schematic illustrations of an interface component 154 that forms an interface between respective portions of a drive cable 130 of a ventricular assist device 20, according to some applications of the present invention. For some applications, the drive cable includes first and second portions. Also referring again to FIG. 10A, typically, the first portion is configured to be disposed within the aortic arch of the subject (i.e., the portion of the aorta corresponding to arrow 145), and the second portion is disposed along the descending aorta (the portion of the aorta corresponding to arrow 147) and is typically configured to extend to a motor unit 23 outside the subject's body. Typically at locations where the drive cable 130 experiences significant curvature, such as in the aortic arch, it is desirable for the drive cable to be relatively flexible. However, a drive cable having greater flexibility is also typically more axially extensible than a drive cable having less flexibility. Thus, for some applications, there is a trade-off between desiring the drive cable to be flexible enough to conform to the curvature of the aortic arch, but on the other hand, not desiring the drive cable to experience significant axial extension, which can result in a loss of control over the axial position of the impeller. For some applications, each portion of the drive cable has a respective level of flexibility. For example, the first portion of the drive cable configured to be disposed within the aortic arch can have a first flexibility, while the second portion of the drive cable configured to be disposed within the descending aorta can have a second flexibility, and the first flexibility is greater than the second flexibility.

[0219] For some application examples, by including fewer wires in the coil of wire 134 in the first portion than in the second portion, the first portion is configured to have a greater flexibility than the second portion. For example, as shown in FIGS. 11A-11B, the first portion can include more than 4 wires and fewer than 8 wires (e.g., 4-8 wires, or 5-7 wires, e.g., 6 wires), and the second portion can include more than 8 wires and fewer than 12 wires (e.g., 8-12 wires, or 9-11 wires, e.g., 10 wires). For some application examples, the length of the first portion of the drive cable is greater than 20 cm (e.g., greater than 25 cm) and less than 40 cm (e.g., less than 35 cm), e.g., 20-40 cm, or 25-35 cm. For some application examples, the length of the second portion of the drive cable is greater than 60 cm (e.g., greater than 70 cm) and less than 100 cm (e.g., less than 90 cm), e.g., 60-100 cm, or 70-90 cm.

[0220] For some application examples, the two portions of the drive cable are connected to each other via interface component 154. Typically, the wires of the two portions are welded to the interface component. For some application examples, a groove 157 is cut into the interface component. The groove is configured such that the stress generated by the wire at the interface is spread over the radius of the groove, as opposed to being concentrated at the point where the wire is welded to the interface component. For some such application examples, the interface component additionally includes a protrusion 158 that holds the wire in place during welding of the wire to the interface component.

[0221] Here, FIGS. 11C, 11D, and 11E are referred to, and FIGS. 11C, 11D, and 11E are schematic explanatory views of an interface 156 between a drive cable of a ventricular assist device and an axial shaft 92 according to some application examples of the present invention. For some application examples, techniques generally similar to those described with reference to FIGS. 11A-11B are used to connect the drive cable to the axial shaft. For some application examples, the proximal end of the axial shaft (which defines the interface 156) includes a groove portion 157 and / or a protrusion portion 158, which are generally as described above and are shown in FIG. 11C.

[0222] Referring to FIG. 11D, for some applications, as the coiled wire approaches the interface 156, the coiled wire is at least partially straightened (i.e., the pitch of the wire is increased), and the angle that the wire makes with the interface does not become sharper than it would be if the wire were straightened. By preventing the angle from becoming sharper, the stress at the point where the wire is welded to the interface component is reduced. Referring to FIG. 11E, for some applications, as the wire approaches the interface 156, in addition to being straightened, the wire is flattened and pushed radially inward. For some applications, the wire is sufficiently flattened such that each wire in the coil contacts the adjacent wire, for example, to form a cylinder as shown. For example, the shape of the wire can be changed from having a circular cross-section with a radius of approximately 0.2 mm to an elliptical cross-section with a minor axis of 0.12 mm. For some applications, the flattening is performed along a length between 1 mm and 3 mm. For some applications, the wire is flattened by installing an overtube 159 around the wire, placing the overtube and the wire on a mandrel, and squeezing the overtube and the wire radially inward. Thereafter, the overtube and the flattened wire are welded to the axial shaft 92 at the interface.

[0223] For some applications, techniques generally similar to those described with reference to FIGS. 11D and 11E are used to connect two portions of the drive cable. For some applications, as the coiled wire approaches the interface component 154, the coiled wire is at least partially straightened (i.e., the pitch of the wire is increased), and the angle that the wire makes with the interface is made not to become sharper than it would be if the wire were not straightened. By making the angle not become sharper, the stress at the point where the wire is welded to the interface component is reduced. For some applications, as the wire approaches the interface component 154, in addition to being straightened, the wire is flattened and pressed radially inward. For some applications, the wire is sufficiently flattened such that each of the wires in the coil comes into contact with the adjacent wire, for example, to form a cylinder. For example, the shape of the wire can be changed from having a circular cross-section with a radius of approximately 0.2 mm to an elliptical cross-section with a minor axis of 0.12 mm. For some applications, the flattening is performed along a length between 1 mm and 3 mm. For some applications, the wire is flattened by installing an overtube (not shown but similar to overtube 159) around the wire, placing the overtube and the wire on a mandrel, and pressing the overtube and the wire radially inward. Thereafter, the overtube and the flattened wire are welded to the interface component 154.

[0224] For some application examples, a clamping technique is used to connect two portions of a drive cable. For some such application examples, the ends of the inner tube and the outer tube are respectively installed inside and outside the ends of the two portions of the drive cable, which will form an interface between the portions. Then, the inner tube is installed on a rigid mandrel, and the inner tube, the outer tube, and the ends of the drive cable are clamped together by applying pressure around the outside of the outer tube. When the ends of the portions of the drive cable, as well as the inner tube and the outer tube are clamped together, this forms an interface between the portions of the drive cable. For some application examples, a similar clamping technique is implemented to connect the drive cable to the axial shaft at interface 156.

[0225] Reference is now made to FIG. 12, which is a schematic illustration of a drive cable 130 of a ventricular assist device 20 including a friction reduction element 170 disposed about at least a portion of the drive cable, according to some applications of the present invention. For some applications, the friction reduction element 170 is used to reduce the friction between the drive cable 130, which rotates during operation of the ventricular assist device, and an outer tube 142, which remains stationary during rotation of the drive cable. In the example shown, the friction reduction element 170 is a ball bearing. However, the scope of the present invention includes using other friction reduction elements to reduce the friction between the drive cable and the outer tube. For example, other rolling element bearings such as cylindrical rollers, spherical rollers, gear bearings, tapered roller bearings, needle roller bearings, and / or toroidal roller bearings may be used. For some applications, the friction reduction element is used as an alternative to including a first outer tube 140 in addition to the second outer tube 142. In the example shown in FIG. 12, the friction reduction element is disposed between the drive cable and the second outer tube, and the ventricular assist device does not include the first and second outer tubes.

[0226] Typically, a ventricular assist device traverses the aortic arch of a subject and / or other portions of the subject's vasculature that are substantially curved. In the absence of friction reducing elements, the drive cable 130 and the tube 142 will typically contact each other, particularly in the curved portions of the vasculature. As described above, the drive cable 130 typically experiences rotational movement and, for some applications, additionally experiences axial movement of advancing and retreating with respect to the tube 142. Thus, in the absence of friction reducing elements (or, as described above, the first outer tube 140), there will be a significant amount of frictional force generated where the drive cable and the outer tube 142 are in contact with each other. Thus, for some applications, the friction reducing element is disposed between the drive cable 130 and the outer tube 142 to reduce the frictional force generated where the drive cable 130 and the outer tube 142 are in contact with each other. For some applications, the friction reducing element is disposed between the drive cable 130 and the outer tube 142 substantially along the entire length of the drive cable 130 and the outer tube 142. Alternatively, the friction reducing element is disposed between the drive cable 130 and the outer tube 142 at locations where the drive cable 130 and the outer tube 142 are configured to be substantially curved, such as where the drive cable 130 and the outer tube 142 are disposed within the aortic arch during operation of the ventricular assist device.

[0227] Here, reference is made to FIG. 13, which is a schematic illustration of a procedure for purging the drive cable 130 of the ventricular assist device 20, according to some applications of the present invention. For some applications, the proximal bearing 116, the axial shaft 92, and the cable 130 are surrounded by the first and second outer tubes 140 and 142, as described above. Typically, both the first and second outer tubes remain stationary during rotation of the drive cable. For some applications, a purging fluid (e.g., a fluid containing glucose or dextrose) is pumped between the first outer tube and the second outer tube, and an opening 146 exists in the first outer tube near the proximal bearing. As described above, typically, the purging system 29 (shown in FIG. 1A) controls the flow - of the purging fluid via the inlet port 86 and the outlet port 88 (shown in FIGS. 7, 8A, and 8B). For some applications, the purging fluid flows between the drive cable 130 and the first outer tube 140, as indicated by the purging fluid flow arrow 148 in FIG. 13. Thus, the interface between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during rotation of the drive cable) is purged. For some applications, some of the purging fluid additionally flows to the interface between the axial shaft and the proximal bearing 116, thereby purging the interface, as indicated by the purging fluid flow arrow 149 in FIG. 13.

[0228] For some applications, the purging fluid is pumped through the lumen 132 defined by the drive cable 130 and the axial shaft 92, such that at least some of the fluid flows all the way to the distal end of the axial shaft. For some applications, thus, some of the purging fluid flows to the interface between the axial shaft and the distal bearing 118, thereby purging the interface as shown by the purging fluid flow arrow 150 in FIG. 13.

[0229] For some applications, a hemostatic valve 152 is disposed at the distal end of the lumen 122 of the distal tip portion 120 as described above. Alternatively or additionally, a plug (not shown) is disposed at the distal end of the lumen 122 of the tip portion 120. Typically, the hemostatic valve and / or the plug prevent blood from flowing into the lumen 122 and / or into the lumen 132. More typically, the plug causes the purging fluid to flow towards the interface between the axial shaft 92 and the distal bearing 118 as shown by the purging fluid flow arrow 150 in FIG. 13 by preventing the purging fluid from flowing out of the distal end of the lumen 122.

[0230] For some applications, alternative techniques to those described above are used to introduce a fluid (e.g., a fluid containing glucose) into the ventricular assist device. In the application shown in FIG. 13, the fluid is allowed to flow distally after passing through the opening 146, as indicated by arrow 149 and as described above. However, for some applications, the distal flow of the fluid is blocked (i.e., there is no flow of fluid as indicated by arrow 149). For some such applications, the fluid is first released into the space between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable) such that the fluid fills the space between the drive cable and the outer tube 140 proximal to the opening 146. For example, the fluid can be pumped into the space through the gap between the first outer tube 140 and the second outer tube 142 as shown. The fluid is then typically maintained in place between the drive cable and the outer tube 140 proximal to the opening 146 throughout the operation of the ventricular assist device. The fluid is configured to remove air from the space between the drive cable and the outer tube and / or is configured to reduce the frictional force between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable).

[0231] For some applications, generally similar techniques are implemented, but the fluid is pumped between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable) during the operation of the ventricular assist device. For example, the fluid can be pumped into the space through the gap between the first outer tube 140 and the second outer tube 142 as shown. Some Regarding the application example, the fluid is continuously pumped between the drive cable and the outer tube during the operation of the ventricular assist device, or is periodically pumped between the drive cable and the outer tube during the operation of the ventricular assist device. Regarding such application examples, it is also noted that although the fluid is pumped between the drive cable and the outer tube, as explained above, the flow of the fluid in the distal direction is blocked and thus does not flow into the bloodstream of the subject. The pumping of the fluid is configured to remove air from the space between the drive cable and the outer tube in order to reduce the frictional force between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable), and / or to remove debris generated by the ventricular assist device from the interface between the drive cable and the outer tube.

[0232] Reference is now made to FIGS. 14A and 14B, which are schematic illustrations of a frame 34 of a ventricular assist device 20 according to some applications of the present invention, with a stator 182 coupled to a proximal portion of the frame. For some applications, the stator is integrally formed with the frame 34, as will be described in more detail hereinafter. Typically, the stator includes a plurality of curved protrusions 66 (e.g., more than two and / or less than eight curved protrusions 66), which extend from the frame 34 when the device 20 is in a configuration where it is not radially constrained, and the protrusions 66 are made of a flexible material, such as a polymer, such as polyurethane and / or silicone. The curvature of the curved protrusions is typically configured to oppose the direction of rotation of the impeller, as will be described in more detail hereinafter. For some applications, due to the use of curved (e.g., curved as described in more detail hereinafter to oppose the direction of rotation of the impeller of the ventricular assist device) protrusions, the stator 182 is configured to reduce the rotational flow component from the blood flow before the blood flows from the proximal end of the frame of the ventricular assist device.

[0233] As described above, typically, the device 20 is inserted transcatheterically into the ventricle of the subject with the frame 34 in a radially constrained state. When released from the catheter, the frame automatically assumes its unconstrained shape due to self-expansion of the frame 34. Typically, during insertion of the frame into the left ventricle, the curved protrusions of the stator are in a folded state and do not substantially increase the minimum diameter by which the frame can be radially constrained as compared to the case where the tube does not contain the curved protrusions. As the frame 34 expands, the curved protrusions are configured to automatically assume their curved configuration due to their connection to the frame 34.

[0234] For some applications, the curved projection 66 is made of a flexible material, such as a polymer, such as polyurethane and / or silicone. The curved projection is typically connected to the strut 186 of the curved frame 34, and the curvature of the curved strut thereby defines the curvature of the curved projection. Typically, the flexible material is connected to the frame 34 such that the flexible material defines a lumen 188 (FIG. 14B) therethrough, and the lumen 188 is aligned with the longitudinal axis of the frame. The axial shaft 92 of the ventricular assist device typically passes through the lumen 188 into the proximal end of the frame.

[0235] For some applications, to facilitate connection of the flexible material to the frame, to shape the flexible material into a desired shape, and / or to facilitate formation of the lumen 188, a plurality of elongate elements 190, such as strings and / or Or a string or wires (which are typically made of a material similar to the elongate element 67) are attached to the proximal end of the frame. For some applications, the curved strut 186 defines at its distal end a ring 192 or other coupling element to which an elongate element 190 is attached. A flexible material is typically attached to the frame such that the curved film of the material is supported by the curved struts and elongate elements, each of the films defining respective curved protrusions. For some applications, the string and / or wires attached to the proximal end of the frame are attached to a circle 191 that defines one of the ends of the lumen 188. For example, during formation of the stator, a mandrel can be installed through the proximal bearing 116 and the elongate element can be attached to the ring 192 and caused to surround the mandrel to define the pattern of elongate elements shown in FIG. 14B. Then, the proximal end of the frame with the elongate element and mandrel is immersed into a material (which is typically a polymer, such as silicone, etc.) while the material is in an uncured liquid state. Thereafter, the material is cured, for example, by being left to dry so that the material solidifies. When the material dries, the mandrel is typically removed. For some applications, the other end of the lumen 188 is defined by the proximal bearing 116 disposed at the proximal end of the frame 34. Typically, the flexible material extends from the circle 191 defined by the string and / or wires to the proximal bearing 116 to define the lumen 188. For some applications, for example, as described above with reference to the suture 53 of the impeller 50, a suture 189 is attached around the curved strut 186 to facilitate the connection between the material and the strut.

[0236] Reference is now made to FIG. 15A, which is a schematic illustration of the flattened profile of the frame 34 of the ventricular assist device 20 according to some applications of the present invention. As shown, the frame includes, at its proximal end, a curved strut 186 with a ring 192 disposed toward the respective tip of the strut. Further, reference is made to FIG. 15B, which is a schematic illustration showing an enlarged view of the proximal end of the frame 34 according to some applications of the present invention. The tip 194 of the curved strut 186 typically defines the orientation of the leading edge of the corresponding blade of the stator (i.e., the curved protrusion) when a flexible material is coupled to the curved strut. Additionally, reference is made to FIG. 15C, which is a schematic illustration of the frame 34 according to some applications of the present invention, showing the frame together with the material defining the curved protrusion 66 coupled to the frame. It can be observed that the orientation of the leading edge of the curved protrusion is defined by the orientation of the corresponding tip of the curved strut.

[0237] As shown in FIG. 15B, the tip 194 of the curved strut 186 is shaped to define an angle alpha with respect to the axial component of the blood flow through the frame, the axial component being indicated by arrow 196 and being parallel toward the proximal end of the frame with respect to the longitudinal axis of the frame. Also, the leading edge of the corresponding curved protrusion typically defines an angle approximately equal to angle alpha with respect to the overall direction of the blood flow, as shown in FIG. 15C. (For some applications, when the strut 186 experiences a radial expansion, the angle of the leading edge of the curved protrusion becomes slightly less than alpha.) For some applications, the angle alpha is greater than 45 degrees (e.g., greater than 60 degrees) and / or less than 85 degrees (e.g., less than 80 degrees), for example, 45 - 85 degrees or 60 - 80 degrees.

[0238] The direction of rotation of the impeller is indicated by arrow 198 in FIG. 15C. FIG. 15 As can be observed in FIG. 15C, the curvature of the curved projections typically opposes the direction of rotation of the impeller (which is the direction of rotation of the rotational flow component in the blood flow as imparted to the blood flow by the impeller). From the distal ends of the curved projections to their proximal ends, the curved projections curve gradually closer to being parallel to the longitudinal axis of the frame. The curvature of the curved projections is such as to reduce the rotational flow component from the blood flow before the blood flows from the proximal end of the ventricular assist device frame.

[0239] Reference is now made to FIGS. 16A, 16B, 16C, and 16D, which are schematic illustrations of a ventricular assist device 20 according to some applications of the present invention, the ventricular assist device including one or more blood pressure measurement tubes 210. As described above, typically, the ventricular assist device includes a tube 24 that traverses the subject's aortic valve, with the proximal end of the tube disposed within the subject's aorta and the distal end of the tube disposed within the subject's left ventricle. Typically, a blood pump (which typically includes an impeller 50) is disposed within the tube 24 and within the subject's left ventricle and is configured to pump blood from the left ventricle through the tube 24 into the subject's aorta. For some applications, the blood pressure measurement tube 210 is configured to extend at least to the outer surface 212 of the tube 24 such that an opening 214 at the distal end of the blood pressure measurement tube is in direct fluid communication with the patient's blood flow outside the tube 24. A pressure sensor 216 (schematically illustrated in FIG. 1A) measures the pressure of the blood within the blood pressure measurement tube. Typically, by measuring the pressure of the blood within the blood pressure measurement tube, the pressure sensor thereby measures the blood pressure of the subject outside the tube 24. Typically, the blood pressure measurement tube 210 extends from outside the subject's body to the opening 214 at the distal end of the tube, and the pressure sensor 216 is disposed, for example, outside the subject's body, toward the proximal end of the tube. For some applications, a computer processor 25 (FIG. 1A) receives an indication of the measured blood pressure and controls the pumping of blood by the impeller in response to the measured blood pressure.

[0240] Referring to FIGS. 16A and 16B, for some applications, one or more blood pressure measurement tubes include one or more left ventricular blood pressure measurement tubes 220, and the one or more left ventricular blood pressure measurement tubes 220 are configured to extend to the outer surface of the blood pressure pump tube 24 at a location along a tube configured to be within the left ventricle of the subject proximal to the blood pump (e.g., proximal to the impeller 50). For such applications, the pressure sensor is configured to measure the left ventricular pressure of the subject by measuring the pressure of the blood in the left ventricular blood pressure measurement tube. For some applications, the ventricular assist device includes two or more such left ventricular blood pressure measurement tubes, as shown, for example, in FIGS. 16A and 16B. For some applications, based on the blood pressure measured in each of the left ventricular blood pressure measurement tubes, the computer processor 25 determines whether an opening of one of the two or more left ventricular blood pressure measurement tubes is blocked. This can occur, for example, due to contact of the opening with a wall portion of the ventricular septum and / or portions within different ventricles. Typically, in response to determining that an opening of one of the two or more left ventricular blood pressure measurement tubes is blocked, the computer processor determines the left ventricular pressure of the subject based on the blood pressure measured in a different one of the two or more left ventricular blood pressure measurement tubes.

[0241] For some applications, one or more blood pressure measurement tubes include one or more aortic blood pressure measurement tubes 222, and the one or more aortic blood pressure measurement tubes 222 are configured to be within the aorta of the subject, as shown in FIG. 16C. At a location along the tube, it is configured to extend to the outer surface of the tube. For such an application example, the pressure sensor is configured to determine the aortic pressure of the subject by measuring the pressure of the blood in the aortic blood pressure measurement tube. For some application examples, the ventricular assist device includes, for example, as shown in FIG. 16C, two or more such aortic blood pressure measurement tubes. For some application examples, based on the blood pressure measured in each of the aortic blood pressure measurement tubes, the computer processor 25 determines whether an opening of one of the two or more aortic blood pressure measurement tubes is blocked. This may occur, for example, due to the opening contacting the wall of the aorta. Typically, in response to determining that an opening of one of the two or more aortic blood pressure measurement tubes is blocked, the computer processor determines the aortic pressure of the subject based on the blood pressure measured in a different one of the two or more aortic blood pressure measurement tubes.

[0242] For some application examples, the ventricular assist device includes both a left ventricular blood pressure measurement tube and an aortic blood pressure measurement tube, all of which extend to the outer surface of the tube 24, for example, as shown in FIG. 16C.

[0243] Still referring to FIG. 16C, as described above, for some applications, the drive cable 130 extends from a motor outside the subject's body to the axial shaft 92, and the impeller 50 is disposed on the axial shaft 92. Typically, the drive cable is disposed within the outer tube 142. For some applications, the drive cable is disposed within the first outer tube 140 and the second outer tube 142, as described above. For some applications, one or more blood pressure measurement tubes are disposed within the outer tube 142 that surrounds the drive cable. For some applications, a portion of one or more blood pressure measurement tubes is defined by the wall of the outer tube 142, as shown. For some applications, within the outer tube 142, the blood pressure measurement tube has an elliptical cross-section (as shown). Typically, this increases the cross-sectional area of the tube compared to when the tube has a circular cross-section. Typically, within each distal portion of the blood pressure measurement tube (which extends to the opening 214), the tube has a circular cross-section. For some applications, the diameter of the distal portion of the tube is greater than 0.2 mm and / or less than 0.5 mm (e.g., between 0.2 and 0.5 mm).

[0244] As shown in FIG. 16A, for some applications, the aortic blood pressure is measured using at least one aortic blood pressure measurement tube 222, and at least one aortic blood pressure measurement tube 222 defines an opening 219 in the outer tube 142 at its distal end. The aortic blood pressure measurement tube is configured to extend from outside the subject's body to the outer surface of the outer tube 142 in the subject's aorta, such that the opening at the distal end of the aortic blood pressure measurement tube is in direct fluid communication with the subject's aortic blood flow. For such applications, it is noted that the aortic blood pressure measurement tube does not extend to the outer surface of tube 24. The blood pressure sensor 216 is configured to measure the subject's aortic blood pressure by measuring the blood pressure in the aortic blood pressure measurement tube. For some applications, the opening 219 in the outer tube 142 is disposed within tube 24, as shown in FIG. 16D. The aortic pressure is measured via the opening 219 because the pressure inside tube 24 at a location downstream of the impeller is typically equal to the aortic pressure.

[0245] As shown in FIGS. 16A and 16B, for some applications, the outer tube 142 defines a groove 215 in a portion of the outer surface of the outer tube configured to be disposed within tube 24. Typically, during insertion of the ventricular assist device into the subject's body, the portion of the blood pressure measurement tube 210 extending from within tube 24 to at least the outer surface of tube 24 is configured to be disposed within the groove such that the portion of the blood pressure measurement tube does not protrude from the outer surface of the outer tube.

[0246] ​Referring now to FIG. 16D, for some applications, the distal portion of the blood pressure measurement tube 210 is disposed over the outside of tube 24. For example, as shown, the blood pressure measurement tube 210 can extend from the outer tube 142 to the proximal end of tube 24 and then the blood pressure measurement tube can be incorporated into the outer surface of tube 24. For some applications, one or more tubes run along the outer surface of tube 24 in the manner shown in FIG. 16D, although the tubes continue to the distal end of tube 24 and to the tip portion 120 of the ventricular assist device. The tubes are used to inflate an inflatable portion of the tip portion as will be described in more detail hereinafter with reference to FIG. 21C.

[0247] The ventricular assist device as described with reference to FIGS. 16A-16D has been described as including a blood pump configured to be disposed within the left ventricle of a subject, although for some applications, the blood pressure measurement tube 210 and techniques described herein for use with the blood pressure measurement tube 210 are used with ventricular assist devices that include a blood pump elsewhere (e.g., within the aorta of a subject). For some applications, generally similar techniques are used with right ventricular assist devices. For example, device 20 can be inserted into the right ventricle and used to pump blood from the right ventricle to the pulmonary artery. For some such applications, the blood pressure measurement tube is used to measure pressures within the right ventricle and / or pulmonary artery. For some applications, a device generally similar to device 20 is used as a cardiac assist device by pumping blood in an antegrade direction from the right atrium to the right ventricle, from the vena cava to the right ventricle, from the right atrium to the pulmonary artery, and / or from the vena cava to the pulmonary artery. For some such applications, the blood pressure measurement tube is used to measure pressures within the right ventricle, vena cava, right atrium, and / or pulmonary artery.

[0248] Generally, the scope of the present invention includes applying any of the devices and methods described herein, with modifications where appropriate, to a right ventricular assist device. The right ventricular assist device typically has a configuration generally similar to those described herein and is used to pump blood from the right ventricle to the pulmonary artery with the tube 24 passing through the pulmonary valve. For some applications, the components of the device 20 are applicable to different types of blood pumps. For example, aspects of the present invention can be applicable to pumps used to pump blood from the vena cava and / or the right atrium into the right ventricle, from the vena cava and / or the right atrium into the pulmonary artery, and / or from the renal vein into the vena cava. Such aspects can include features of the pump portion 27, the impeller 50, features of the drive cable 130, devices and methods for measuring blood pressure, devices and methods for measuring flow, and the like.

[0249] For some applications, techniques generally similar to those described with reference to the blood pressure measurement tube 210 are implemented using an electrical wire extending from within the blood pressure pump tube 24 (and which typically extends outside the subject's body) to the outer surface of the tube 24, with at least the tip of the wire being in electrical communication with the subject's blood flow outside the tube 24. The blood pressure of the subject outside the tube 24 (e.g., the subject's ventricular blood pressure and / or the subject's aortic blood pressure) is measured by detecting electrical parameters using the portion of the wire that is in electrical communication with the subject's blood flow outside the tube 24.

[0250] Reference is now made to FIGS. 17A, 17B, and 17C, which are schematic illustrations of the outer tube 142 of the ventricular assist device 20 according to some applications of the present invention. The outer tube includes a Pitot tube 225 configured to measure blood flow through the device's tube 24. The portion of the outer tube 142 shown in FIGS. 17A-17C is typically disposed within the tube 24. For some applications, a flow obstruction 226 (which is typically funnel-shaped) is configured to create a stagnation region near the stagnation point pressure tap 227. For some applications, as shown in FIG. 17A, a flow straightener 228 is added to the outer surface of the tube 142 to remove any swirling component of the flow (which does not contribute to the axial flow rate). Alternatively, the stagnation point pressure tap is disposed sufficiently proximally within the funnel-shaped flow obstruction 226 such that, as shown in FIG. 17B, the flow obstruction itself acts to remove the swirling component of the flow before the blood reaches the stagnation point pressure tap. For some applications, the stagnation point pressure tap includes a short tube 233 that protrudes from the outer tube 142 within the funnel-shaped flow obstruction 226 and is oriented such that the opening of the short tube 233 faces in the direction of the axial blood flow through the tube 24. The outer tube 142 additionally defines an opening 219 that generally functions as a static pressure tap 229 as described above. The pressures within the stagnation point pressure tap 227 and the static pressure tap 229 are measured using pressure sensors, such as those disposed outside the subject's body as described above with reference to FIGS. 16A-16D.

[0251] In some applications, the flow through tube 24 is calculated based on the pressure measurements. For example, the flow through tube 24 can be calculated using the following equation:

[0252]

Number

[0253] Here, Q is the flow through tube 24, C is a calibration constant, which is determined experimentally and takes into account factors such as impeller speed and the geometry of pressure taps 227 and 229, A is the cross-sectional area of tube 24 (excluding the area occupied by the outer tube 142), ΔP is the difference between the stagnation point pressure (measured via pressure tap 227) and the static pressure (measured via pressure tap 229), ρ is the fluid density of the blood.

[0254] Here, reference is made to FIG. 18, which is a schematic illustration of a ventricular assist device 20 according to some applications of the present invention, and the distal tip portion 120 of the device is a radially expandable atraumatic distal tip portion. As described above, the ventricular assist device typically includes a tube 24 that traverses the aortic valve of the subject, with the proximal portion of the tube disposed within the aorta of the subject and the distal portion of the tube disposed within the left ventricle of the subject. Tube 24 has 1 in the distal portion of the tube Defines one or more blood inlet openings 108 and defines one or more blood outlet openings 109 in the proximal portion of the tube. The blood pump of the ventricular assist device is configured to be disposed within tube 24 and is configured to pump blood from the left ventricle into tube 24 through one or more blood inlet openings and from tube 24 into the aorta through one or more blood outlet openings. Typically, the radially expandable atraumatic distal tip portion 120 is disposed within the left ventricle of the subject distal to the one or more blood inlet openings. The distal tip portion is configured to be inserted into the left ventricle in a radially constrained configuration. Typically, at least a portion of the distal tip portion is disposed inside a delivery catheter 143 (e.g., shown in FIG. 1B) during insertion of the distal tip portion into the left ventricle, and the delivery catheter maintains the distal tip portion in a radially constrained configuration. The distal tip portion is configured to assume a configuration in which it is not radially constrained within the left ventricle of the subject, and in the non-radially constrained configuration, at least a portion 232 of the distal tip portion is radially expanded relative to the radially constrained configuration of the distal tip.

[0255] For some applications, the radially expandable atraumatic distal tip portion 120 includes a frame 234 made of a shape memory material (e.g., nitinol), the frame 234 being shape set such that when the frame is released from the delivery catheter, it expands radially. Typically, the frame is covered by a biocompatible blood-impermeable material 236 such as polyurethane, polyester, and / or silicone, and the biocompatible blood-impermeable material 236 is typically configured to form a continuous surface covering the frame. For some applications, the distal tip portion additionally includes an atraumatic distal tip 238, which can have a shape similar to that of the distal tip portion 120 as described above with reference to FIG. 6C and / or as described hereinafter with reference to FIG. 21B.

[0256] The radially expandable atraumatic distal tip portion 120 is typically configured such that in a radially unconstrained configuration of the distal tip portion, the radially expandable portion 232 of the distal tip portion separates one or more blood inlet openings 108 from the inner structures of the left ventricle in three dimensions. Thus, the radially expandable portion 232 of the distal tip portion separates one or more blood inlet openings from the ventricular septum, chordae tendineae, papillary muscles, and / or the apex of the left ventricle. For some applications, the radially expandable portion 232 of the distal tip portion is shaped to direct blood flow from the left ventricle into one or more of the blood inlet openings as indicated by arrow 240 in FIG. 18.

[0257] Reference is now made to FIGS. 19A-19B, which are schematic illustrations of a ventricular assist device 20 according to some application examples of the present invention, wherein the ventricular assist device distal tip portion 120 of the device is a radially expandable atraumatic distal tip portion. Also, reference is made to FIGS. 20A-20B, which are schematic illustrations of a ventricular assist device 20 according to some alternative application examples of the present invention, wherein the ventricular assist device distal tip portion 120 of the device is a radially expandable atraumatic distal tip portion. FIGS. 19A and 20A show the distal tip portion in its radially constrained configuration while at least partially disposed inside the delivery catheter 143, and FIGS. 19B and 20B show the distal tip portion in its unconstrained radially configuration. Generally, the distal tip portion 120 as shown in FIGS. 19A-19B and FIGS. 20A-20B has generally the same functionality as described above with reference to the distal tip portion 120 as shown in FIG. 18.

[0258] As described above, typically, at least a portion of the distal tip portion 120 is disposed inside the delivery catheter 143 during insertion of the distal tip into the left ventricle, and the delivery catheter maintains the distal tip portion in a radially constrained configuration as shown in FIGS. 19A and 20A. For some applications, the distal tip portion is configured such that the distal region 244 of the distal tip portion projects from the distal end of the delivery catheter when the delivery catheter maintains the distal tip portion in a radially constrained configuration. Typically, in at least the radially constrained configuration of the distal tip portion, the distal region is at least semi-rigid and is shaped to converge radially in the longitudinal direction toward the distal end 246 of the distal tip portion. Typically, the delivery catheter is inserted into the subject's vasculature through a puncture site. For some applications, the semi-rigid distal region that converges radially of the distal tip portion is configured to act as a dilator by expanding the puncture site during insertion of the delivery catheter through the puncture site. Thus, the delivery catheter and the components of the ventricular assist device disposed within the delivery catheter can be inserted into the puncture site without the need for pre-dilation of the puncture site and without the need for a separate introducer device to facilitate insertion of the delivery catheter through the puncture site. For some applications, the distal region is configured to enable percutaneous insertion of the catheter into the punctured blood vessel by placing a first guide wire through the distal region of the distal tip portion. Thereafter, the distal region is used to guide the catheter along an arcuate biological structure (e.g., the aortic arch) by tracking the course and shape of a second guide wire that is not stiffer than the first guide wire. For some such applications, the delivery catheter 143 itself acts as an introducer. Typically, the delivery catheter has an inner diameter smaller than 9 mm. For example, the delivery catheter can be an 8 French catheter.For some applications, the delivery catheter is inserted through the puncture site via a short introducer device.

[0259] For some applications, the distal tip portion 120 is configured such that, in a configuration where the distal tip portion is not radially constrained, the distal end 246 of the distal tip portion is enclosed within a radially expandable portion 232 of the distal tip portion. For some applications, the distal end is retracted proximally such that the distal end is enclosed within the radially expandable portion. For example, the distal tip portion can include a spring 249 and / or an elastomeric material configured to retract the distal end of the distal tip portion as shown in the transition from FIGS. 19A to 19B. For some applications, the distal end is inverted such that the distal end is enclosed within the radially expandable portion of the distal tip portion. For example, the transition from FIGS. 20A to 20B shows that the distal end 246 of the distal tip portion 120 is inverted as indicated by arrow 264. For some applications, enclosing the distal end within the radially expandable portion prevents the distal tip from snagging in tendons and / or from causing trauma to internal structures of the left ventricle.

[0260] Referring to FIG. 19B, for some applications, the distal tip portion includes a plurality of longitudinal struts 248, and the plurality of longitudinal struts 248 are shape set to curve radially outward. Typically, the struts are made from a shape memory material such as nitinol. For some applications, the struts are covered by a biocompatible blood-impermeable material 250 such as polyurethane, polyester, and / or silicone, and the biocompatible blood-impermeable material 250 is typically configured to form a continuous surface covering the struts. Referring to FIG. 20B, for some applications, the distal tip portion is braided It includes the shaped memory material 260. For some applications, the braided shaped memory material is at least partially covered by a biocompatible blood-impermeable material 262 such as polyurethane, polyester, and / or silicone, etc., and the biocompatible blood-impermeable material 262 is typically configured to form a continuous surface covering the braided shaped memory material. Alternatively, the braided shaped memory material is not covered.

[0261] Here, FIGS. 21A, 21B, 21C, and 21D are referred to, and FIGS. 21A, 21B, 21C, and 21D are schematic explanatory views of the distal tip portion 120 of the ventricular assist device 20 according to some applications of the present invention, and the distal tip portion is configured to be non-invasive. As shown in FIG. 21A, for some applications, the distal tip portion includes a J-shaped tip 270 at its distal end. As shown in FIG. 21B, for some applications, the distal tip portion includes a bulbous tip 272 at its distal end. As shown in FIGS. 21A and 21B, for some applications, proximal to the J-shaped tip or the bulbous tip, the distal tip portion is shaped externally to define a frustum 274. Typically, the proximal end 276 of the frustum acts as a stopper to prevent the advancement of the delivery catheter 143 passing through the proximal end in generally the same manner as described with respect to the flared portion 124 with reference to FIG. 6C.

[0262] For some applications, the distal tip portion has a straight configuration, and in the straight configuration, the distal tip portion is shaped to define a frustum of a cone that extends from the proximal end of the frustum to the distal tip of the distal tip portion. For example, a guide wire (such as guide wire 10) inserted through lumen 122 (shown in FIGS. 6A - 6C) defined by the distal tip portion can maintain the distal tip portion in its straight configuration. For some such applications, the distal tip portion has an unconstrained configuration (the distal tip portion is configured to assume an unconstrained configuration inside the ventricle (e.g., due to the guide wire being removed from inside the distal tip portion)), and in the unconstrained configuration, the distal portion of the frustum of the cone is shaped as a J - tip as shown in FIG. 21A.

[0263] As shown in FIG. 21C, for some applications, the outer surface of the distal tip portion includes an inflatable portion 278 (such as a balloon), and the inflatable portion 278 is configured to be inflated when the distal tip portion is disposed inside the left ventricle of the subject. For some such applications, the inflation lumen for inflating the inflatable portion is configured to pass through outer tube 142 and then along the outer surface of tube 24 to the inflatable portion of the distal tip portion. For example, the inflation lumen can be configured in a manner generally similar to blood pressure measurement tube 210 as shown in FIG. 16D, but can continue running along the outer surface of tube 24 to the distal end of the tube and then continue to the inflatable portion of the distal tip portion. For some applications, the distal end of the distal tip portion includes a rounded portion 280. As described above, typically, the distal tip portion includes a hemostatic valve 152 at its distal end.

[0264] As shown in FIG. 21D, for some applications, the outer surface of the distal tip portion includes a radially expandable portion 282 (e.g., a radially expandable mesh and / or a radially expandable frame as shown), and the radially expandable portion 282 is configured to self-expand when the distal tip portion is disposed inside the left ventricle of the subject.

[0265] As shown in FIGS. 21C and 21D, the non-invasive distal tip portion 120 is typically configured such that in the expanded configuration or radially expanded configuration of the distal tip portion, the expanded portion or radially expanded portion of the distal tip portion three-dimensionally separates one or more blood inlet openings 108 from the inner structure of the left ventricle. Thus, the expanded portion or radially expanded portion of the distal tip portion separates one or more blood inlet openings 108 from the ventricular septum, chordae tendineae, papillary muscles, and / or the apex of the left ventricle. For some applications, the expanded portion or radially expanded portion of the distal tip portion is shaped to direct blood flow from the left ventricle into one or more of the blood inlet openings as described above with reference to the distal tip portion 120 as shown in FIG. 18.

[0266] Reference is now made to FIGS. 22A and 22B, which are schematic illustrations of the distal tip portion 120 of the ventricular assist device 20 according to some applications of the present invention, in a configuration stiffened axially and in a configuration not stiffened axially, respectively. As described above, for some applications, the distal tip portion is configured such that when the delivery catheter maintains the distal tip portion in a radially constrained configuration, the distal region 244 of the distal tip portion projects from the distal end of the delivery catheter. Typically, at least in the axially stiffened configuration of the distal tip portion, the distal region is at least semi-rigid and is shaped to converge radially in the longitudinal direction toward the distal end 246 of the distal tip portion. Typically, the delivery catheter is inserted into the subject's vasculature through a puncture site. More typically, the distal tip portion defines a lumen 122, and as described above, the guide wire 10 is inserted through the lumen 122. For some applications, the radially converging semi-rigid distal region of the distal tip portion is configured to act as a dilator by expanding the puncture site during insertion of the delivery catheter through the puncture site. Thus, the delivery catheter and the components of the ventricular assist device disposed within the delivery catheter can be inserted into the puncture site without the need for pre-dilation of the puncture site and without the need for a separate introducer device to facilitate insertion of the delivery catheter through the puncture site. For some applications, the distal region is configured to enable percutaneous insertion of the catheter into the punctured blood vessel by placing a first guide wire through the distal region of the distal tip portion. Thereafter, the distal region is used to guide the catheter along an arcuate biological structure (e.g., the aortic arch) by tracking the course and shape of a second guide wire that is less stiff than the first guide wire. For some such applications, the delivery catheter 143 itself acts as an introducer. Typically, the delivery catheter has an inner diameter of less than 9 mm.For example, the delivery catheter can be an 8 French catheter. For some applications, the delivery catheter is inserted through the puncture site via a short introducer device.

[0267] For some applications, the distal tip portion is made of a flexible material (e.g., silicone, etc.) and the spring 290 is disposed around the lumen 122. During insertion of the ventricular assist device into the subject's body, a rigid or semi-rigid reinforcing element 292 (e.g., a rigid or semi-rigid tube) is placed inside the distal region 244 of the distal tip portion to stiffen the distal region. This configuration is shown in FIG. 22A. Subsequently, the reinforcing element is retracted so that the distal region of the distal tip portion is non-invasive (e.g., elastic and flexible) as shown in FIG. 22B.

[0268] Reference is now made to FIGS. 23A and 23B, which show, respectively, several It is a schematic explanatory diagram of the distal tip portion 120 of the ventricular assist device 20 according to that application example. Regarding some application examples, the distal region 144 of the distal tip portion is shaped as a cone and has slits 294 (for example, two slits) in the cone. During the insertion of the ventricular assist device into the body of the subject, the distal region is maintained in its conical shape by the delivery catheter 143. This configuration is shown in FIG. 23A. Then, when the delivery catheter is being retracted, the distal region is configured to form a two-dimensional circular or elliptical shape by splitting into two semi-circular 296 or semi-elliptical shapes around the slit, as shown in FIG. 23B. In the configuration shown in FIG. 23B, the distal tip portion is typically configured to be non-invasive and is configured to two-dimensionally separate one or more blood inlet openings 108 from the inner structure of the left ventricle. In this way, the distal tip portion separates one or more blood inlet openings 108 from the ventricular septum, chordae tendineae, papillary muscles, and / or the apex of the left ventricle.

[0269] Reference is now made to FIGS. 24A and 24B, which are schematic illustrations of the distal tip portion 120 of the ventricular assist device 20 according to some applications of the present invention in a radially constrained configuration and a non-radially constrained configuration, respectively. For some applications, the distal region 244 of the distal tip portion is shaped as a cone and includes slits 294 (e.g., four slits) therein. During insertion of the ventricular assist device into the body of the subject, the distal region is maintained in its conical shape by the delivery catheter 143. This configuration is shown in FIG. 24A. Thereafter, when the delivery catheter is being retracted, the distal region is configured to form a three-dimensional basket shape by splitting into four arms 298 around the slits, as shown in FIG. 24B. (It is noted that the fourth arm is hidden from the perspective of FIG. 24B.) In the configuration shown in FIG. 24B, the distal tip portion is typically configured to be non-invasive and to three-dimensionally separate one or more blood inlet openings 108 from the inner structure of the left ventricle. In this way, the distal tip portion separates one or more blood inlet openings 108 from the ventricular septum, chordae tendineae, papillary muscles, and / or the apex of the left ventricle.

[0270] For some applications, the distal tip portion 120 has a pointed distal region 244, and the diameter of the distal tip portion at the proximal end of the distal region is approximately equal to the diameter of the delivery catheter 143. Typically, the pointed distal region 244 has a length that is less than half of the total length of the distal tip portion (e.g., less than one quarter). More typically, the flexibility of the pointed distal region is greater than the flexibility of the proximal region of the distal tip portion. Typically, the distal region is configured to be generally straight into a conical shape when a sufficiently stiff guide wire is inserted therein. For some applications, the distal region is configured to curl into a J shape in the absence of any external force acting on the distal region (e.g., as shown in FIG. 21A).

[0271] Typically, the distal region of the distal tip portion acts as an expander for the delivery catheter 143 and enables percutaneous insertion of the catheter into the punctured blood vessel by placing a first guide wire through the distal region of the distal tip portion. Thereafter, the distal tip portion is used to guide the catheter along an arcuate biological structure (e.g., the aortic arch) by tracking the course and shape of a second guide wire that is not stiffer than the first guide wire. For some applications, the distal region of the distal tip portion is configured to curl when the second guide wire is withdrawn, as described above.

[0272] For some applications, the features of the distal tip portion 120, described with reference to FIGS. 18-24B, and the techniques for implementing the same, are combined with the features (described above with reference to FIGS. 6A-6C and / or FIG. 13) of the tip portion 120 and the techniques for implementing the same. Here, FIG. 25A is referenced, and FIG. 25A is a schematic illustration of a first portion 160A and a second portion 160B of a coupling element configured to promote radial contraction (e.g., during crimping) of an impeller (e.g., impeller 50 described above) independent of other components of a ventricular assist device, according to some applications of the present invention. The first and second portions 160A and 160B are configured to engage with each other. The first portion is disposed on the impeller, and the second portion is disposed on the frame 34, e.g., on the distal bearing 118 of the frame 34. It is noted that only a particular portion of the impeller is shown in FIG. 25A for illustrative purposes.

[0273]

[0274] ​Also, reference is made to FIGS. 25B and 25C, which are schematic explanatory views of respective stages of impeller crimping according to some application examples of the present invention. For some application examples, before crimping the outer portion of the ventricular assist device (e.g., the frame 34 of the left ventricular assist device 20 as shown), by engaging portions 160A and 160B with each other and elongating the impeller axially so as to radially contract the impeller, the impeller can be radially contracted. Thereafter, the outer portion of the left ventricular assist device can be radially contracted. For some application examples, crimping the impeller in this way reduces the possibility that the impeller is damaged during crimping of the outer portion of the left ventricular assist device. Thereafter, when the impeller and the frame are disposed in the left ventricle of the subject, the first and second portions of the coupling element are released from each other so that the impeller can move relative to the frame 34.

[0275] Alternatively or additionally to the crimping technique shown in FIGS. 25A-25C, as described above, only one of the ends of the impeller (e.g., the proximal end of the impeller) is connected to the axial shaft, and the other end (e.g., the distal end) is slidable relative to the axial shaft, whereby the impeller is configured to be crimped. The impeller is crimped by the other end of the impeller sliding along the shaft, such that the impeller becomes axially elongated.

[0276] Reference is now made to FIG. 26, which is a schematic illustration of a stopper 300 configured to prevent distal advancement of the impeller 50 of the ventricular assist device 20 during withdrawal of the ventricular assist device from a subject's body, according to some applications of the present invention. As described above, typically, to withdraw the ventricular assist device from the subject's body, the delivery catheter 143 is advanced distally over the frame 34 and the impeller 50, causing the frame and impeller to assume their radially constrained configuration. In some cases, there is a risk that the drive cable 130 may snap when the impeller is pushed distally by the delivery catheter. For some applications, in the event that the drive cable snaps, distal advancement of the proximal end of the impeller then causes the stopper 300 to engage the shoulder portion 302, thereby preventing further advancement of the proximal end of the impeller. It is noted that the stopper is configured such that it does not engage the shoulder portion 302 during normal operation of the ventricular assist device (and throughout the entire axial forward and backward movement cycle described above).

[0277] For some applications (not shown), a plurality of electrodes are disposed over a distal portion of a left ventricular assist device. A computer processor 25 (FIG. 1A) applies a current between the most distal electrode and the most proximal electrode, where the most distal electrode is typically configured to be disposed near the apex of the heart and the most proximal electrode is typically configured to be disposed above the aortic valve. The conductance of the current between each pair of electrodes is then measured by the computer processor. For some applications, the application of the current and the conductance measurement are performed using techniques generally similar to those described in an article entitled “The Conductance Volume Catheter Technique for Measurement of Left Ventricular Volume in Young Piglets” by Cassidy et al. (Pediatric Research, Vol. 31, No. 1, 1992, pp. 85-90). For some applications, the computer processor is configured to derive a real-time left ventricular pressure-volume loop of a subject based on the conductance measurement. For some applications, the computer processor controls the rotational speed of the impeller in response to the derived pressure-volume loop.

[0278] With respect to all aspects of the ventricular assist device 20 described with reference to FIGS. 1A-26, FIGS. 1A and 1B show the ventricular assist device 20 within the left ventricle of a subject. However, for some applications, the device 20 is placed inside the right ventricle of the subject, and the device is configured to cross the pulmonary valve of the subject. It should be noted that the techniques described herein are applied with modifications where necessary. For some applications, the components of the device 20 are applicable to different types of blood pumps. For example, aspects of the present invention can be applicable 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. Such aspects can include features of the impeller 50, features of the pump portion 27, the drive cable 130, devices and methods for measuring blood pressure, etc. Alternatively or additionally, the device 20 and / or a portion thereof (e.g., the impeller 50 even if the tube 24 is absent) is placed inside a different part of the subject's body and is configured to assist in pumping blood from that part. For example, the device 20 and / or a portion thereof (e.g., the impeller 50 even if the tube 24 is absent) can be placed within a blood vessel and used to pump blood through the blood vessel. For some applications, the device 20 and / or a portion thereof (e.g., the impeller 50 even if the tube 24 is absent) is configured, with modifications where necessary, to be placed within the subclavian vein or jugular vein at the junction of the vein and lymphatic vessel and is used to increase the flow of lymph fluid from the lymphatic vessel into the vein. Since the scope of the present invention includes using the devices and methods described herein at anatomical locations other than the left ventricle and aorta, the ventricular assist device and / or a portion thereof may be referred to herein (in the specification and claims) as a blood pump.

[0279] Here, FIGS. 27A and 27B are referred to, and FIGS. 27A and 27B are schematic explanatory views of a ventricular assist device 308 according to some application examples of the present invention. The device includes a valve 70 for preventing blood backflow, for example, when the impeller 50 of the ventricular assist device fails. Different from the ventricular assist device 20 described above with reference to FIGS. 1A - 26, the ventricular assist device 308 includes an impeller disposed not in the left ventricle but in the aorta (for example, as described in WO18 / 078615 by Tuval, which is incorporated herein by reference). For some application examples, the impeller is configured in generally the same manner as the impeller 50 described above. The impeller is disposed at the proximal end of a tube 312 (for example, a polyester tube), the tube 312 crosses the aortic valve, and the frame 310 supports the tube in an open configuration. FIG. 27A shows a ventricular assist device as configured when the impeller of the ventricular assist device is functioning properly, and there is a blood flow from the left ventricle 22 to the aorta 30 through the tube 312 (which crosses the aortic valve 26), and the blood flow is indicated by arrow 72.

[0280] For some application examples, the tube 312 includes a valve 70 in the region of the tube configured to be disposed distally with respect to the impeller 50 and near the aortic valve, as shown in FIG. 27B. For example, when the impeller 50 fails and there is a blood backflow through the tube 312 (as indicated by the blood flow arrow 73 in FIG. 27B), the valve tips of the valve 70 are configured to close so that there is substantially no blood flow retrograde from the aorta to the left ventricle. For some application examples (not shown), the tube 312 includes a valve 70 at the proximal end of the tube, which is configured to be disposed in the aorta.

[0281] Here, FIGS. 28A, 28B, and 28C are referred to, and FIGS. 28A, 28B, and 28C are schematic explanatory views of a ventricular assist device 308 according to some application examples of the present invention. The device includes a safety balloon 80 for preventing blood backflow, for example, when the impeller of the ventricular assist device fails. Different from the ventricular assist device 20 described above with reference to FIGS. 1A - 26, the ventricular assist device 308 includes an impeller disposed not in the left ventricle but in the aorta (for example, as described in WO18 / 078615 by Tuval, which is incorporated herein by reference). For some application examples, the impeller is configured in generally the same manner as the impeller 50 described above. The impeller is disposed at the proximal end of a tube 312 (for example, a polyester tube), the tube 312 traverses the aortic valve, and the frame 310 supports the tube in an open configuration. FIG. 28A shows a ventricular assist device as configured when the impeller of the ventricular assist device is functioning properly, and there is a blood flow from the left ventricle 22 to the aorta 30 through the tube 312 (which traverses the aortic valve 26), and the blood flow is indicated by arrow 72. For some application examples, the ventricular assist device 308 includes a balloon 80 in a region of the tube configured to be disposed distally with respect to the impeller 50 and near the aortic valve, as shown in FIG. 28B. For example, when the impeller 50 fails and there is a blood backflow through the tube 312 (as indicated by the blood flow arrow 73 in FIG. 28B), the computer processor 25 is configured to inflate the balloon so that the tube 312 is blocked and there is substantially no blood flow retrograde from the aorta to the left ventricle.

[0282] For some applications, the ventricular assist device 308 includes a balloon 80 at the distal end of the tube 312, and the balloon 80 is configured to be disposed within the left ventricle as shown in FIG. 28C. For example, if the impeller 50 fails and there is a reverse blood flow through the tube 312 (as indicated by the blood flow arrow 73 in FIG. 28C), the computer processor 25 is configured to inflate the balloon so that the tube 312 is blocked and there is substantially no reverse blood flow from the aorta into the left ventricle.

[0283] The scope of the present invention includes combining any of the devices and methods described herein with any of the devices and methods described in one or more of the following applications, all of which are incorporated herein by reference: International Patent Application No. PCT / IL2017 / 051273 by Tuval, titled "Blood Pumps" (published as WO18 / 096531), filed on November 21, 2017, claiming priority from U.S. Provisional Patent Application No. 62 / 425,814 by Tuval, filed on November 23, 2016; International Application No. PCT / IL2017 / 051158 by Tuval, titled "Ventricular assist device" (published as WO18 / 078615), filed on October 23, 2017, claiming priority from U.S. Patent Application No. 62 / 412,631 by Tuval, filed on October 25, 2016, and U.S. Patent Application No. 62 / 543,540 by Tuval, filed on August 10, 2017; International Patent Application No. PCT / IL2017 / 051092 by Tuval, titled "Blood vessel tube" (published as WO18-061002), filed on September 28, 2017, claiming priority from U.S. Provisional Patent Application No. 62 / 401,403 by Tuval, filed on September 29, 2016; U.S. Patent Application Publication No. 2018 / 0169313 by Schwammenthal, which is the U.S. national stage of International Patent Application No. PCT / IL2016 / 050525 (published as WO16 / 185473) by Schwammenthal filed on May 18, 2016, claiming priority from U.S. Provisional Patent Application No. 62 / 162,881 by Schwammenthal filed on May 18, 2015, titled "Blood pump"; U.S. Patent Application Publication No. 2017 / 0100527 by Schwammenthal, which is the U.S. national stage of International Patent Application No. PCT / IL2015 / 050532 (published as WO15 / 177793) by Schwammenthal filed on May 19, 2015, claiming priority from U.S. Provisional Patent Application No. 62 / 000,192 by Schwammenthal filed on May 19, 2014, titled "Blood pump"; (a) U.S. Patent No. 10,039,874 by Schwammenthal, which is the U.S. national stage of International Patent Application No. PCT / IL2014 / 050289 (published as WO14 / 141284) by Schwammenthal filed on March 13, 2014, claiming priority from (a) U.S. Provisional Patent Application No. 61 / 779,803 by Schwammenthal filed on March 13, 2013, and (b) U.S. Provisional Patent Application No. 61 / 914,475 by Schwammenthal filed on November 11, 2013, both titled "Renal pump"; U.S. Patent No. 9,764,113 by Tuval issued on September 19, 2017, titled "Curved catheter", claiming priority from U.S. Provisional Patent Application No. 61 / 914,470 by Tuval filed on December 11, 2013, titled "Curved catheter"; and U.S. Patent No. 9,597,205 by Tuval, which is the U.S. national stage of International Patent Application No. PCT / IL2013 / 050495 (published as WO13 / 183060) by Tuval, filed on June 6, 2013, claiming priority from U.S. Provisional Patent Application No. 61 / 656,244 by Tuval, filed on June 6, 2012, entitled "Prosthetic renal valve".

[0284] Those skilled in the art will recognize that the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the present invention includes both combinations and sub - combinations of the various features described above that would occur to those skilled in the art upon reading the foregoing description, as well as variations and modifications thereof that are not found in the prior art. Aspects of the present invention are as follows. [Aspect 1] An apparatus, the apparatus comprising a blood pump configured to be installed inside a subject's body, wherein the blood pump includes an impeller having a proximal bushing and a distal bushing, a frame configured to be disposed around the impeller, the frame including a proximal bearing and a distal bearing, an axial shaft configured to pass through the proximal bearing and the distal bearing of the frame and the proximal bushing and the distal bushing of the impeller, and the proximal bushing of the impeller is connected to the axial shaft such that the proximal bushing is held in an axially fixed position relative to the axial shaft, the distal bushing of the impeller is not connected to the axial shaft such that the distal bushing is not held in an axially fixed position relative to the axial shaft. The impeller defines a radially constrained configuration and a non-radially constrained configuration. In the radially constrained configuration, the impeller is introduced into the body of the subject. In the non-radially constrained configuration, the impeller is configured to pump blood into the body of the subject. The impeller is configured to change from its radially constrained configuration to its non-radially constrained configuration by the distal bushing sliding over the axial shaft. Device. [Aspect 2] The impeller according to aspect 1, wherein the impeller is configured to be installed inside the left ventricle of the subject and is also configured to pump blood from the left ventricle of the subject to the aorta of the subject. [Aspect 3] The impeller according to aspect 1, wherein the impeller is configured to be installed inside the right ventricle of the subject and is also configured to pump blood from the right ventricle of the subject to the pulmonary artery of the subject. [Aspect 4] The device according to aspect 1, wherein the impeller is configured to be installed inside a blood vessel of the subject. [Aspect 5] The device according to aspect 1, wherein the impeller is configured to be installed inside a heart chamber of the subject. [Aspect 6] The impeller is at least one helical elongated element extending from the proximal bushing to the distal bushing, a spring disposed along an axis around which the helical elongated element is wound inside the helical elongated element, a film of material supported between the helical elongated element and the spring, At least one flexible elongate element, said at least one flexible elongate element extending from said spring to said helical elongate element and configured to maintain said helical elongate element within a given distance from said spring and said at least one flexible elongate element is at least one flexible elongate element selected from the group consisting of strings and wires The device according to any one of aspects 1 to 5, comprising. [Aspect 7] The device further comprises a delivery catheter said delivery catheter being configured to maintain said impeller in a radially constrained configuration during introduction of said impeller into the body of the subject when said impeller is released from said delivery catheter, said impeller is configured to self-expand, thereby causing said distal bushing to slide proximally over said axial shaft and said impeller to assume a configuration in which it is not radially constrained, and to retract said impeller from the body of the subject, the distal end of said delivery catheter and said impeller are moved relative to each other, and said distal end of said delivery catheter is configured to cause said distal bushing to slide distally over said axial shaft, whereby said delivery catheter is configured to cause said impeller to assume a configuration in which it is radially constrained. The device according to any one of aspects 1 to 5. [Aspect 8] A device, said device comprising a ventricular assist device said ventricular assist device comprising an impeller configured to be disposed inside the left ventricle of a subject, and a frame configured to be disposed around said impeller A motor configured to drive the impeller to pump blood from the left ventricle of the subject to the aorta by rotating the impeller and includes The impeller is configured to experience an axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the left ventricle and the aorta. [Aspect 9] The impeller includes proximal cushioning and distal cushioning The frame includes a proximal bearing and a distal bearing The ventricular assist device further includes an axial shaft configured to pass through the proximal bearing and the distal bearing defined by the frame, and the proximal cushioning and the distal cushioning of the impeller The axial shaft is connected to at least one of the proximal cushioning and the distal cushioning of the impeller, and the at least one cushioning is held in an axially fixed position with respect to the axial shaft The apparatus according to aspect 8, wherein the axial shaft is not held in an axially fixed position with respect to the proximal bearing and the distal bearing [Aspect 10] The apparatus according to aspect 8, wherein the ventricular assist device does not include any thrust bearing configured to be disposed within the body of the subject [Aspect 11] The ventricular assist device further includes one or more thrust bearings configured to be disposed outside the body of the subject, and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject. The apparatus according to aspect 8 [Aspect 12] The motor is configured to drive the impeller to pump blood from the left ventricle of the subject to the aorta of the subject by rotating the impeller in a given direction of rotation. The ventricular assist device An axial shaft, wherein the impeller is disposed on the axial shaft, the axial shaft, and A drive cable configured to extend from outside the body of the subject to the axial shaft, the drive cable being configured to impart rotational movement from the motor to the impeller by rotating, at least a portion of the drive cable including a plurality of wires disposed in a coiled configuration, the coiled configuration being such that in response to the drive cable rotating in the given direction of rotation, the plurality of wires disposed in the coiled configuration are at least partially unwound and the portion of the drive cable shortens axially, the drive cable and The device according to aspect 8, further comprising. [Aspect 13] A sensor configured to detect an indication of axial movement of the impeller and to generate a sensor signal in response thereto, the sensor, and A computer processor configured to receive the sensor signal and to generate an output in response thereto, the computer processor and The device according to any one of aspects 8 to 12, further comprising. [Aspect 14] The device according to aspect 13, wherein the computer processor is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. [Aspect 15] The device according to aspect 13, wherein the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. [Aspect 16] The apparatus according to aspect 13, wherein the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal. [Aspect 17] The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, and is configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure, the apparatus according to aspect 16. [Aspect 18] The apparatus according to aspect 17, wherein the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. [Aspect 19] A magnet, wherein the impeller is coupled to the magnet such that axial movement of the impeller causes the magnet to experience axial movement, the magnet, a sensor configured to detect a magnetic flux generated by the magnet and to generate a sensor signal in response thereto, the sensor and a computer processor configured to receive the sensor signal and to generate an output in response thereto, the computer processor further comprising the apparatus according to any one of aspects 8 to 12. [Aspect 20] The apparatus according to aspect 19, wherein the computer processor is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. [Aspect 21] The apparatus according to aspect 19, wherein the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. [Aspect 22] The apparatus according to aspect 19, wherein the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal. [Aspect 23] The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, and configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure, the apparatus according to aspect 22. [Aspect 24] The apparatus according to aspect 23, wherein the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. [Aspect 25] The impeller includes proximal bumping and distal bumping, the frame includes a proximal bearing and a distal bearing, the ventricular assist device further includes an axial shaft configured to pass through the proximal bearing and the distal bearing of the frame and the proximal bumping and the distal bumping of the impeller, the impeller is coupled to the axial shaft and is configured to cause the axial shaft to experience an axial forward and backward movement with respect to the proximal bearing and the distal bearing of the frame, the apparatus according to any one of aspects 8 to 12. [Aspect 26] The axial shaft of aspect 25 is configured to clean the interface between the axial shaft and the proximal bearing and the distal bearing of the frame by experiencing forward and backward movement in the axial direction with respect to the proximal bearing and the distal bearing of the frame. [Aspect 27] In contrast to the case where the axial shaft does not experience forward and backward movement in the axial direction with respect to the proximal bearing and the distal bearing of the frame, the axial shaft of aspect 25 is configured to reduce heat generation at the interface between the axial shaft and the proximal bearing and the distal bearing of the frame by experiencing forward and backward movement in the axial direction with respect to the proximal bearing and the distal bearing of the frame. [Aspect 28] An apparatus, the apparatus comprising: a blood pump, the blood pump comprising: an impeller including a proximal bushing and a distal bushing, the impeller being configured to pump blood through the body of the subject; a frame configured to be disposed around the impeller, the frame including a proximal bearing and a distal bearing; an axial shaft configured to pass through the proximal bearing and the distal bearing of the frame and the proximal bushing and the distal bushing of the impeller; and the axial shaft is connected to at least one of the proximal bushing and the distal bushing of the impeller, and the at least one bushing is held in a position fixed in the axial direction with respect to the axial shaft; the axial shaft is not held in a position fixed in the axial direction with respect to the proximal bearing and the distal bearing. [Aspect 29] The device according to aspect 28, wherein the blood pump does not include any thrust bearings configured to be disposed within the body of the subject. [Aspect 30] The device according to aspect 28, wherein the blood pump further includes one or more thrust bearings configured to be disposed outside the body of the subject, and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject. [Aspect 31] A sensor configured to detect an indication of the axial movement of the impeller and to generate a sensor signal in response thereto; A computer processor configured to receive the sensor signal and to generate an output in response thereto; The device according to any one of aspects 28 to 30, further comprising: [Aspect 32] The device according to aspect 31, wherein the computer processor is configured to generate an output indicating the cardiac cycle of the subject in response to receiving the sensor signal. [Aspect 33] The device according to aspect 31, wherein the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. [Aspect 34] The device according to aspect 31, wherein the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal. [Aspect 35] The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, The apparatus according to aspect 34, configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure. [Aspect 36] The apparatus according to aspect 35, wherein the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. [Aspect 37] A magnet, wherein the impeller is coupled to the magnet such that axial movement of the impeller causes the magnet to experience axial movement, and A sensor configured to detect a magnetic flux generated by the magnet and to generate a sensor signal in response thereto, and A computer processor configured to receive the sensor signal and to generate an output in response thereto The apparatus according to any one of aspects 28 to 30, further comprising. [Aspect 38] The apparatus according to aspect 37, wherein the computer processor is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. [Aspect 39] The apparatus according to aspect 37, wherein the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. [Aspect 40] The apparatus according to aspect 37, wherein the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal. [Aspect 41] The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, and The apparatus according to aspect 40, configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure. [Aspect 42] The apparatus according to aspect 41, wherein the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. [Aspect 43] The apparatus according to any one of aspects 28 to 30, wherein the impeller is configured to pump blood from a first location within the body of the subject to a second location within the body of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the first location and the second location. [Aspect 44] The apparatus according to aspect 43, wherein the impeller is configured to pump blood from the left ventricle of the subject to the aorta of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the left ventricle and the aorta. [Aspect 45] The impeller is configured to pump blood from the right ventricle of the subject to the pulmonary artery of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right ventricle and the pulmonary artery. The apparatus according to aspect 43. [Aspect 46] The apparatus according to aspect 43, wherein the impeller is configured to pump blood from the right atrium of the subject to the right ventricle of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the right atrium and the right ventricle. [Aspect 47] The impeller is configured to pump blood from the great vein of the subject to the right ventricle of the subject, and the impeller is configured to experience an axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the great vein and the right ventricle, the apparatus according to aspect 43. [Aspect 48] The impeller is configured to pump blood from the right atrium of the subject to the pulmonary artery of the subject, and the impeller is configured to experience an axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the right atrium and the pulmonary artery, the apparatus according to aspect 43. [Aspect 49] The impeller is configured to pump blood from the great vein of the subject to the pulmonary artery of the subject, and the impeller is configured to experience an axial forward and backward movement with respect to the frame in response to a periodic change in the pressure difference between the great vein and the pulmonary artery, the apparatus according to aspect 43. [Aspect 50] A motor configured to drive the impeller to pump blood through the subject's body by rotating the impeller in a given direction of rotation, A drive cable configured to extend from outside the subject's body to the axial shaft, the drive cable being configured to impart a rotational movement from the motor to the impeller by rotating, at least a portion of the drive cable including a plurality of wires arranged in a coiled configuration, the coiled configuration being such that in response to the drive cable rotating in the given direction of rotation, the plurality of wires arranged in the coiled configuration are at least partially unwound and the portion of the drive cable shortens axially, the drive cable further comprising the apparatus according to aspect 43. [Aspect 51] The impeller is connected to the axial shaft, and the impeller is configured to cause the axial shaft to experience an axial forward and backward movement with respect to the proximal bearing and the distal bearing of the frame, according to aspect 43 of the device. [Aspect 52] The axial shaft is configured to clean the interface between the axial shaft and the proximal bearing and the distal bearing of the frame by experiencing the axial forward and backward movement with respect to the proximal bearing and the distal bearing of the frame, according to aspect 51 of the device. [Aspect 53] In contrast to the case where the axial shaft does not experience the axial forward and backward movement with respect to the proximal bearing and the distal bearing of the frame, the axial shaft is configured to reduce heat generation at the interface between the axial shaft and the proximal bearing and the distal bearing of the frame by experiencing the axial forward and backward movement with respect to the proximal bearing and the distal bearing of the frame, according to aspect 51 of the device. [Aspect 54] A device, the device comprising a blood pump, the blood pump comprising an impeller, the impeller being configured to be installed inside the body of a subject and also configured to pump blood through the body of the subject, and a frame configured to be disposed around the impeller and the blood pump does not include any thrust bearing configured to be disposed within the body of the subject. [Aspect 55] The blood pump further includes one or more thrust bearings configured to be disposed outside the body of the subject, and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the body of the subject, the apparatus according to aspect 54. [Aspect 56] A sensor configured to detect an indication of the axial movement of the impeller and further configured to generate a sensor signal in response thereto, and A computer processor configured to receive the sensor signal and further configured to generate an output in response thereto, The apparatus according to aspect 54 or aspect 55, further comprising. [Aspect 57] The apparatus according to aspect 56, wherein the computer processor is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. [Aspect 58] The apparatus according to aspect 56, wherein the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. [Aspect 59] The apparatus according to aspect 56, wherein the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal. [Aspect 60] The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, and configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure, the apparatus according to aspect 59. [Aspect 61] The apparatus according to aspect 60, wherein the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. [Aspect 62] A magnet, wherein the impeller is connected to the magnet, and axial movement of the impeller causes the magnet to experience axial movement, and the magnet A sensor configured to detect a magnetic flux generated by the magnet and further configured to generate a sensor signal in response thereto, and the sensor A computer processor configured to receive the sensor signal and further configured to generate an output in response thereto, and the computer processor The apparatus according to aspect 54 or aspect 55, further comprising [Aspect 63] The apparatus according to aspect 62, wherein the computer processor is configured to generate an output indicative of the cardiac cycle of the subject in response to receiving the sensor signal. [Aspect 64] The apparatus according to aspect 62, wherein the computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal. [Aspect 65] The apparatus according to aspect 62, wherein the computer processor is configured to vary the rotational speed of the impeller based at least in part on the sensor signal. [Aspect 66] The computer processor is configured to determine the left ventricular pressure of the subject based at least in part on the sensor signal, and configured to vary the rotational speed of the impeller based at least in part on the determined left ventricular pressure. The apparatus according to aspect 65. [Aspect 67] The apparatus according to aspect 66, wherein the computer processor is configured to reduce the rotational speed of the impeller in response to determining that the left ventricular pressure of the subject has decreased. [Aspect 68] The apparatus according to aspect 54 or aspect 55, wherein the impeller is configured to pump blood from a first location within the body of the subject to a second location within the body of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the pressure difference between the first location and the second location. [Aspect 69] The apparatus according to aspect 68, wherein the impeller is configured to pump blood from the left ventricle of the subject to the aorta of the subject, and the impeller is configured to experience an axial forward and backward movement relative to the frame in response to a periodic change in the ...

Claims

1. An apparatus, comprising: ventricular assist devices, The ventricular assist device comprises: an impeller configured to be placed inside the left ventricle of the subject; a frame configured to be disposed around the impeller; a motor configured to drive the impeller to rotate the impeller and thereby pump blood from the left ventricle to the aorta of the subject; Including, The entire impeller is configured to undergo axial forward and backward movement relative to the frame in response to cyclic changes in pressure differential between the left ventricle and the aorta.

2. the impeller includes a proximal bushing and a distal bushing; the frame includes a proximal bearing and a distal bearing; The ventricular assist device further includes an axial shaft configured to pass through the proximal and distal bearings defined by the frame and the proximal and distal bushings of the impeller; the axial shaft is coupled to at least one of the proximal and distal bushings of the impeller such that the at least one bushing is held in an axially fixed position relative to the axial shaft; The device of claim 1 , wherein the axial shaft is not held in an axially fixed position relative to the proximal and distal bearings.

3. The apparatus of claim 1 , wherein the ventricular assist device does not include any thrust bearings configured to be disposed within the subject's body.

4. 10. The apparatus of claim 1, wherein the ventricular assist device further comprises one or more thrust bearings configured to be disposed outside the subject's body, and wherein opposition to thrust generated by rotation of the impeller is provided solely by the one or more thrust bearings disposed outside the subject's body.

5. the motor is configured to drive the impeller to rotate the impeller in a given direction of rotation to pump blood from a left ventricle of the subject to an aorta of the subject; The ventricular assist device comprises: an axial shaft, the impeller being disposed on the axial shaft; a drive cable configured to extend from outside the subject's body to the axial shaft, the drive cable configured to rotate to impart rotational motion from the motor to the impeller, at least a portion of the drive cable including a plurality of wires arranged in a coiled configuration, the coiled configuration such that in response to the drive cable rotating in the given direction of rotation, the plurality of wires arranged in the coiled configuration at least partially unwind, causing the portion of the drive cable to axially shorten; The apparatus of claim 1 further comprising:

6. a sensor configured to detect an indication of axial movement of the impeller and to generate a sensor signal in response thereto; and a computer processor configured to receive the sensor signal and to generate an output in response thereto; The apparatus of any one of claims 1 to 5, further comprising:

7. The apparatus of claim 6 , wherein the computer processor is configured to vary a rotational speed of the impeller based at least in part on the sensor signal.

8. a magnet, the impeller being coupled to the magnet such that axial movement of the impeller causes the magnet to experience axial movement; a sensor configured to detect magnetic flux generated by the magnet and to generate a sensor signal in response thereto; and a computer processor configured to receive the sensor signal and to generate an output in response thereto; The apparatus of any one of claims 1 to 5, further comprising:

9. The apparatus of claim 8 , wherein the computer processor is configured to vary a rotational speed of the impeller based at least in part on the sensor signal.

10. the impeller includes a proximal bushing and a distal bushing; the frame includes a proximal bearing and a distal bearing; the ventricular assist device further includes an axial shaft configured to pass through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller; 6. The apparatus of claim 1, wherein the impeller is coupled to the axial shaft such that the impeller causes the axial shaft to undergo axial forward and backward movement relative to the proximal and distal bearings of the frame.

11. 11. The device of claim 10, wherein the axial shaft is configured to undergo an axial forward and backward movement relative to the proximal and distal bearings of the frame to clear an interface between the axial shaft and the proximal and distal bearings of the frame.

12. 11. The apparatus of claim 10, wherein the axial shaft is configured to experience axial forward and backward movement relative to the proximal and distal bearings of the frame, relative to a case in which the axial shaft does not experience the axial forward and backward movement relative to the proximal and distal bearings of the frame, thereby reducing heating at an interface between the axial shaft and the proximal and distal bearings of the frame.

13. An apparatus, comprising: Including a blood pump, The blood pump comprises: an impeller including a proximal bushing and a distal bushing, the impeller configured to pump blood through a body of the subject; a frame configured to be disposed about the impeller, the frame including a proximal bearing and a distal bearing; an axial shaft configured to pass through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller; Including, the axial shaft is coupled to at least one of the proximal and distal bushings of the impeller such that the at least one bushing is held in an axially fixed position relative to the axial shaft; The device, wherein the axial shaft is not held in an axially fixed position relative to the proximal and distal bearings.

14. An apparatus, comprising: Including a blood pump, The blood pump comprises: an impeller configured to be placed inside a body of a subject and configured to pump blood through the body of the subject; a frame configured to be disposed around the impeller; and Including, The apparatus, wherein the blood pump does not include any thrust bearing configured to be disposed within the subject's body.

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