Low-profile blood pumps

Abstract

Apparatus and methods are described including a blood pump (20) that includes an impeller (50) that pumps blood of the subject through a pump-outlet tube (24), such that the blood exits the pump-outlet tube (24) through blood-outlet openings (109). A driven diametric magnet (52) is coupled to the impeller (50) such that the impeller rotates with the driven diametric magnet (52). A driving diametric magnet (54) is configured for positioning alongside the driven diametric magnet (52) within the subject's body. A drive cable (130) rotates the driving diametric magnet (54), while the driving diametric magnet (54) is alongside the driven diametric magnet (52), such that the driving diametric magnet (54) rotates the driven diametric magnet (52) via magnetic coupling, thereby rotating the impeller (50). Other applications are also described.

Description

[0001] LOW-PROFILE BLOOD PUMPS

[0002] CROSS-REFERENCES TO RELATED APPLICATIONS

[0003] The present application claims priority from (a) US Provisional Patent Application 63 / 693,758 to Tuval et al., entitled "Diametric magnets for blood pump," filed September 12, 2024, and (b) US Provisional Patent Application 63 / 693,751 to Tuval et al., entitled "Inserting a left- ventricular assist device via a forearm artery," filed September 12, 2024. The aforementioned applications are incorporated herein by reference.

[0004] TECHNICAL FIELD

[0005] Applications of the present disclosure relate generally to medical devices, and specifically to blood pumps, e.g., for ventricular assist devices.

[0006] BACKGROUND

[0007] Ventricular assist devices are mechanical circulatory support devices designed to assist and unload cardiac chambers in order to maintain or augment cardiac output. They are used in patients suffering from a failing heart and in patients at risk for deterioration of cardiac function during percutaneous coronary interventions. Most commonly, a left-ventricular assist device is applied to a defective heart in order to assist left-ventricular functioning. In some cases, a right-ventricular assist device is used in order to assist right-ventricular functioning. Such ventricular assist devices are either designed to be permanently implanted or mounted on a catheter for temporary placement.

[0008] SUMMARY

[0009] In some conventional ventricular assist devices, a drive cable, which passes through a tube running through the subject’s vasculature, is mechanically coupled to an impeller disposed within the subject’s heart. The drive cable is rotated by an external motor. As the drive cable rotates within the tube, the impeller rotates, thereby pumping blood from the heart. By contrast, in some applications of the present disclosure a blood pump is provided in which the drive cable is magnetically coupled to the impeller via a pair of diametric magnets, rather than being mechanically coupled to the impeller. Advantageously, the design of the blood pump typically obviates the need for pumping a purging fluid through the pump during the operation of the pump. In some applications, the design of the blood pump reduces the profile of the device that is inserted via an arterial insertion site (e.g., a femoral insertion site) relative to devices that require pumping of a purging fluid through the pump during the operation of the pump.

[0010] In some applications, the blood pump includes a pump-outlet tube shaped to define one or more blood-outlet openings and configured for insertion into the subject’s heart. In some applications, the blood pump includes an impeller disposed within the distal portion of the pumpoutlet tube and configured to pump blood of the subject proximally through the pump-outlet tube, such that the blood exits the pump-outlet tube through the blood-outlet openings. In some applications, the blood pump includes a driven diametric magnet coupled to the impeller such that the impeller rotates with the driven diametric magnet, a driving diametric magnet configured for positioning alongside the driven diametric magnet within the subject’s body, and a drive cable. In some applications, the drive cable is coupled to the driving diametric magnet and is configured to rotate the driving diametric magnet, while the driving diametric magnet is alongside the driven diametric magnet, such that the driving diametric magnet rotates the driven diametric magnet via magnetic coupling, thereby rotating the impeller. Typically, the drive cable passes through a sealed tube containing a lubricant, which lubricates the drive cable.

[0011] Traditionally, left-ventricular assist devices are inserted via a lower-body artery, such as a femoral artery, of the subject. However, this method of insertion compromises the mobility of the subject, this compromise being particularly problematic for cases in which the device is used for a long period of time. Some applications of the present disclosure provide an alternate method for inserting and positioning the left-ventricular assist device. The method typically includes percutaneously inserting a sheath into an upper-body artery of a subject, and advancing the sheath, via the upper-body artery, into a left ventricle of the subject. In some applications, the method includes advancing the left-ventricular assist device, through the sheath and not over a guidewire, until a pump-outlet tube of the left-ventricular assist device spans an aortic valve of the subject such that the distal portion of the pump-outlet tube is positioned within the left ventricle and the blood-outlet openings are positioned within an aorta of the subject, and deploying the pump-outlet tube and a frame of the left-ventricular assist device from the sheath.

[0012] In some applications, the upper-body artery is a forearm artery (e.g., a radial artery or an ulnar artery) of a forearm (e.g., a right forearm) of the subject. Although the forearm arteries are typically relatively narrow, the ventricular assist device can be configured to have a relatively small diameter. For example, given that the device is not advanced to the left ventricle over a guidewire, the drive cable need not be shaped to define a guidewire lumen, such that the drive cable - and hence the delivery tube, frame, and sheath - can have a smaller diameter than would otherwise be possible.

[0013] Applications of the present disclosure further provide a left-ventricular assist device including a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube and configured to span an aortic valve of a subject such that the blood-outlet openings are positioned within an aorta of the subject and a distal portion of the pumpoutlet tube is positioned within a left ventricle of the subject. In some applications, the left- ventricular assist device includes an inflatable frame coupled to an outer wall of the distal portion of the pump-outlet tube and configured to inflate within the left ventricle. Advantageously, the outer diameter of the inflatable frame, while the frame is deflated, is typically smaller than that of a radially-constrained self-expandable frame, such that the device can be more easily inserted via the forearm artery.

[0014] In some applications, the left-ventricular assist device includes an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings. In some applications, the left-ventricular assist device includes a delivery tube configured to extend from outside a body of the subject, via a forearm artery of the subject, through the pump-outlet tube. In some applications, the left-ventricular assist device includes a drive cable, which passes through the delivery tube and is coupled to the impeller such that the drive cable is configured to rotate the impeller.

[0015] There is therefore provided, in accordance with some applications of the present disclosure, an apparatus including a blood pump. The blood pump includes a pump-outlet tube shaped to define one or more blood-outlet openings and configured for insertion into a heart of a subject, an impeller configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube through the blood-outlet openings, a driven diametric magnet coupled to the impeller such that the impeller rotates with the driven diametric magnet, a driving diametric magnet configured for positioning alongside the driven diametric magnet within a body of the subject, and a drive cable coupled to the driving diametric magnet and configured to rotate the driving diametric magnet, while the driving diametric magnet is alongside the driven diametric magnet, such that the driving diametric magnet rotates the driven diametric magnet via magnetic coupling, thereby rotating the impeller.

[0016] In some applications, each one of respective lengths of the driven diametric magnet and the driving diametric magnet is at least 10 mm.

[0017] In some applications, each one of respective diameters of the driven diametric magnet and the driving diametric magnet is less than 2.5 mm.

[0018] In some applications, the driven diametric magnet and the driving diametric magnet are configured to remain magnetically coupled to one another even when a rotational speed of the driven diametric magnet and the driving diametric magnet is greater than 20,000 rotations per minute.

[0019] In some applications, the pump-outlet tube is configured for insertion into the subject’s heart such that the distal portion of the pump-outlet tube is within a left ventricle of the subject’s heart and the blood-outlet openings are within an aorta of the subject.

[0020] In some applications, the impeller, driven diametric magnet, and driving diametric magnet are configured to sustain a rotational speed of the impeller of at least 20,000 rotations per minute for a mean pressure gradient between the aorta and the left ventricle of up to at least 60 mmHg.

[0021] In some applications, the impeller, driven diametric magnet, and driving diametric magnet are configured to sustain a flow rate of the blood of at least three liters per minute for a mean pressure gradient between the aorta and the left ventricle of up to at least 60 mmHg.

[0022] In some applications, the blood pump is configured for use without any purging fluid being pumped through any portion of the blood pump.

[0023] In some applications, the driven diametric magnet is disposed within the pump-outlet tube.

[0024] In some applications, the driven diametric magnet is proximal to the pump-outlet tube.

[0025] In some applications, the blood pump further includes: a sealed drive-cable-bearing tube; and a lubricant within the drive-cable-bearing tube, and the drive cable passes through the drive-cable-bearing tube and is lubricated by the lubricant.

[0026] In some applications, the lubricant obviates a need for pumping a purging fluid through the drive-cable-bearing tube while the drive cable rotates the driving diametric magnet.

[0027] In some applications, the driving diametric magnet is disposed within a distal end of the drive-cable-bearing tube.

[0028] In some applications, the blood pump further includes a driving-magnet tube containing the driving diametric magnet and coupled to a distal end of the drive-cable-bearing tube.

[0029] In some applications, the blood pump further includes a delivery tube configured to extend, from outside the body of the subject, through the pump-outlet tube to a distal portion of the pumpoutlet tube, the driven diametric magnet is disposed within the delivery tube, the delivery tube is shaped to define an opening that is at least partly proximal to the driven diametric magnet, and the driving diametric magnet is configured to: advance through the body of the subject while disposed within the delivery tube proximally to the driven diametric magnet, and subsequently, advance through the opening until the driving diametric magnet is alongside the driven diametric magnet.

[0030] In some applications, the blood pump further includes: a driven-magnet tube containing the driven diametric magnet; and another tube containing the driving diametric magnet and including a rounded head configured to guide the other tube through the opening when the rounded head is pushed against the driven-magnet tube.

[0031] In some applications, the blood pump further includes: another tube containing the driving diametric magnet; and multiple steering wires coupled to the other tube and configured to steer the other tube through the opening.

[0032] In some applications, the blood pump further includes an inflatable element disposed within the delivery tube and configured to inflate, thereby pushing the driving diametric magnet through the opening.

[0033] In some applications, the blood pump is shaped to define a guidewire lumen passing from a proximal end of the drive cable at least to a distal end of the pump-outlet tube, the blood pump is for use with a guidewire passing through the guidewire lumen, the driving diametric magnet is configured to advance, through the body, over the guidewire, and the driving diametric magnet is configured to advance through the opening following a withdrawal of a distal end of the guidewire to a position proximal to the driven diametric magnet. In some applications, the apparatus further includes a guide string configured to extend from outside the body of the subject at least to a distal end of the driven diametric magnet, and the driving diametric magnet is configured to advance, over the guide string, through the body of the subject until the driving diametric magnet is alongside the driven diametric magnet.

[0034] In some applications, the driven diametric magnet is disposed within the pump-outlet tube, and the guide string passes through one of the blood-outlet openings.

[0035] In some applications, the blood pump further includes an expandable frame surrounding the impeller within the pump-outlet tube, and the guide string is coupled to the frame.

[0036] In some applications, the apparatus further includes a sheath configured to extend from outside the body of the subject to the subject’s heart, the pump-outlet tube is configured for insertion into the subject’s heart while disposed within a distal end of the sheath, and the driving diametric magnet is configured to advance, over the guide string, alongside the sheath.

[0037] In some applications, the blood pump further includes another tube containing the driving diametric magnet and configured to advance over the guide string, and a sum of respective diameters of a proximal end of the sheath, which is configured to pass into the body of the subject, and the other tube is less than 5 mm.

[0038] In some applications, the blood pump further includes: a driven-magnet tube containing the driven diametric magnet; and a push-pull rod coupled to a proximal end of the driven-magnet tube and configured to extend from outside the body of the subject to the subject’s heart.

[0039] In some applications, the blood pump is shaped to define a guidewire lumen passing from a proximal end of the push-pull rod at least to a distal end of the pump-outlet tube, the blood pump is for use with a guidewire passing through the guidewire lumen, and the pump-outlet tube is configured for insertion into the subject’s heart over the guidewire.

[0040] In some applications, the guide string is more flexible than the guidewire.

[0041] There is further provided, in accordance with some applications of the present disclosure, a method for positioning, within a body of a subject, an apparatus that includes a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube, a frame coupled to a distal portion of the pump-outlet tube, an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pumpoutlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings, a delivery tube configured to extend, from outside the body of the subject, through the pump-outlet tube, and a drive cable passing through the delivery tube and coupled to the impeller such that the drive cable is configured to rotate the impeller. The method includes percutaneously inserting a sheath into an upper-body artery of a subject, advancing the sheath, via the upper-body artery, into a left ventricle of the subject, advancing the apparatus, through the sheath without the apparatus being guided by a guidewire, until the pump-outlet tube spans an aortic valve of the subject such that the distal portion of the pump-outlet tube is positioned within the left ventricle and the blood-outlet openings are positioned within an aorta of the subject, and deploying the pump-outlet tube and the frame from the sheath.

[0042] In some applications, the upper-body artery is selected from the group of arteries consisting of: a brachial artery, an axillary artery, and a subclavian artery.

[0043] In some applications, the upper-body artery is a forearm artery of a forearm of the subject.

[0044] In some applications, the forearm artery is a radial artery or an ulnar artery of the subject.

[0045] In some applications, the forearm is a right forearm of the subject.

[0046] In some applications, advancing the apparatus through the sheath includes advancing the apparatus through the sheath without any tubular structure interposing between the delivery tube and the sheath.

[0047] In some applications, the frame is self-expandable, advancing the apparatus through the sheath includes advancing the apparatus through the sheath while the frame is radially constrained by the sheath, and deploying the frame from the sheath includes causing the frame to expand, within the left ventricle, upon exiting the sheath.

[0048] In some applications, the frame is coupled to an outer wall of the distal portion of the pump-outlet tube and is inflatable, advancing the apparatus through the sheath includes advancing the apparatus through the sheath while the frame is deflated, and the method further includes, subsequently to deploying the frame from the sheath, inflating the frame.

[0049] In some applications, an outer diameter of the frame, while the frame is deflated, is less than 2.4 mm.

[0050] In some applications, the drive cable is not shaped to define a guidewire lumen.

[0051] In some applications, an outer diameter of the drive cable is less than 1.2 mm.

[0052] In some applications, an outer diameter of the delivery tube is less than 2.2 mm.

[0053] In some applications, the method further includes, subsequently to deploying the pumpoutlet tube and the frame from the sheath, withdrawing a distal end of the sheath into a brachiocephalic trunk of the subject such that the distal end of the sheath remains in the brachiocephalic trunk while the impeller pumps the blood.

[0054] In some applications, the method further includes measuring an aortic pressure of the subject, while the distal end of the sheath is in the brachiocephalic trunk, using a pressure sensor connected to a channel between the sheath and the delivery tube.

[0055] In some applications, an outer diameter of the sheath is less than 2.8 mm.

[0056] In some applications, the sheath is a 7 Fr sheath.

[0057] In some applications, the sheath is a 6 Fr sheath.

[0058] There is further provided, in accordance with some applications of the present disclosure, an apparatus for use with a sheath percutaneously inserted into an upper-body artery of a subject. The apparatus includes a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube and configured to advance through the sheath and without being guided by a guidewire, while the sheath passes, via the upper-body artery, into a left ventricle of the subject, until the pump-outlet tube spans an aortic valve of the subject such that a distal portion of the pump-outlet tube is positioned within the left ventricle and the blood-outlet openings are positioned within an aorta of the subject. The apparatus further includes a frame coupled to the distal portion of the pump-outlet tube and configured for deployment from the sheath, together with the pump-outlet tube, subsequently to advancing through the sheath, an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings, a delivery tube configured to extend, from outside a body of the subject, through the pump-outlet tube, and a drive cable, which passes through the delivery tube, is not shaped to define a guidewire lumen, and is coupled to the impeller such that the drive cable is configured to rotate the impeller.

[0059] There is further provided, in accordance with some applications of the present disclosure, an apparatus including a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube and configured to span an aortic valve of a subject such that the blood-outlet openings are positioned within an aorta of the subject and a distal portion of the pump-outlet tube is positioned within a left ventricle of the subject. The apparatus further includes an inflatable frame coupled to an outer wall of the distal portion of the pump-outlet tube and configured to inflate within the left ventricle, an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings, a delivery tube configured to extend from outside a body of the subject, via a forearm artery of the subject, through the pump-outlet tube, and a drive cable, which passes through the delivery tube and is coupled to the impeller such that the drive cable is configured to rotate the impeller.

[0060] In some applications, the forearm artery is a radial artery or an ulnar artery of the subject.

[0061] In some applications, the forearm is a right forearm of the subject.

[0062] In some applications, an outer diameter of the frame, while the frame is deflated, is less than 2.4 mm.

[0063] In some applications, the frame includes multiple inflatable rings surrounding the pumpoutlet tube and arranged along a longitudinal axis of the pump-outlet tube.

[0064] In some applications, the frame further includes multiple inflatable tubes that pass between the rings along the longitudinal axis and establish fluid communication between the rings.

[0065] In some applications, the impeller is inflatable, and is configured to inflate within the left ventricle.

[0066] In some applications, an outer diameter of the impeller, while the impeller is deflated, is less than 2.2 mm.

[0067] In some applications, the drive cable is shaped to define a guidewire lumen, and the pumpoutlet tube is configured to advance, to the aortic valve, over a guidewire passing through the guidewire lumen.

[0068] In some applications, the drive cable is not shaped to define a guidewire lumen, the apparatus is for use with a sheath that passes, via the forearm artery, into the left ventricle, and the pump-outlet tube is configured to advance, to the aortic valve, through the sheath.

[0069] In some applications, the apparatus further includes the sheath, and an outer diameter of the sheath is less than 2.8 mm.

[0070] In some applications, the sheath is a 7 Fr sheath.

[0071] In some applications, the sheath is a 6 Fr sheath.

[0072] There is further provided, in accordance with some applications of the present disclosure, a method for positioning, within a body of a subject, an apparatus that includes a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube, an inflatable frame coupled to an outer wall of a distal portion of the pump-outlet tube, an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the bloodoutlet openings, a delivery tube configured to extend, from outside a body of the subject, through the pump-outlet tube, and a drive cable, which passes through the delivery tube and is coupled to the impeller such that the drive cable is configured to rotate the impeller. The method includes advancing the apparatus through a forearm artery of the subject, while the frame is deflated, until the pump-outlet tube spans an aortic valve of the subject such that the blood-outlet openings are positioned within an aorta of the subject and the distal portion of the pump-outlet tube is positioned within a left ventricle of the subject, and inflating the frame within the left ventricle.

[0073] In some applications, the drive cable is not shaped to define a guidewire lumen, the method further includes inserting a sheath, via the forearm artery of the subject, into the left ventricle of the subject, advancing the apparatus includes advancing the apparatus through the sheath, and the method further includes, prior to inflating the frame, deploying the pump-outlet tube and the frame from the sheath.

[0074] In some applications, advancing the apparatus through the sheath includes advancing the apparatus through the sheath without any tubular structure interposing between the delivery tube and the sheath.

[0075] The present disclosure will be more fully understood from the following detailed description of applications thereof, taken together with the drawings, in which:

[0076] BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Fig. l is a schematic illustration of a blood pump, in accordance with some applications of the present disclosure;

[0078] Fig. 2 is a schematic illustration of two diametric magnets magnetically coupled to one another, in accordance with some applications of the present disclosure;

[0079] Fig. 3 is a schematic illustration of a blood pump, in accordance with other applications of the present disclosure;

[0080] Figs. 4A, 4B, 4C, 4D, 4E, and 4F show respective steps of a method for deploying a blood pump, in accordance with some applications of the present disclosure;

[0081] Fig. 5 is a schematic illustration of a ventricular assist system, in accordance with some applications of the present disclosure;

[0082] Fig. 6 is a schematic illustration of a ventricular assist device that has been deployed, in accordance with some applications of the present disclosure;

[0083] Fig. 7 is a schematic illustration of a distal portion of a ventricular assist device, in accordance with some applications of the present disclosure;

[0084] Fig. 8 is a flow diagram for a method for positioning a ventricular assist device within the body of a subject, in accordance with some applications of the present disclosure;

[0085] Figs. 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H, 91, 9J, and 9K show steps in a method for positioning a ventricular assist device within the body of a subject, in accordance with some applications of the present disclosure; and

[0086] Fig. 10 is a schematic illustration of a frame and a distal portion of a pump-outlet tube, in accordance with some applications of the present disclosure. DETAILED DESCRIPTION

[0087] BLOOD PUMP WITH DIAMETRIC MAGNETS

[0088] Reference is initially made to Fig. 1, which is a schematic illustration of a blood pump 20, in accordance with some applications of the present disclosure.

[0089] Pump 20 includes a pump-outlet tube 24, which is typically elongate, in that the axial length of the pump-outlet tube is typically substantially larger than its diameter. Pump-outlet tube 24 is shaped to define one or more (e.g., 2-8, such as 2-4) blood-outlet openings 109 at a proximal portion 106 of pump-outlet tube 24, typically near the proximal end of the pump-outlet tube. Furthermore, the pump-outlet tube typically defines one or more blood-inlet openings 108 at a distal portion 102 of the tube, typically near or at the distal end of the pump-outlet tube. As shown in Fig. 1, in some applications, the pump-outlet tube defines a single axially-facing blood-inlet opening 108. Alternatively, the pump-outlet tube defines a plurality of blood-inlet openings 108 facing laterally or obliquely with respect to the longitudinal axis of the pump-outlet tube. For example, in some applications, distal portion 102 includes a frustoconical end portion shaped to define multiple (e.g., 2-4, 10-50, 50-100, or more than 100) blood-inlet openings 108.

[0090] Pump 20 further includes an impeller 50, which is typically disposed within distal portion 102 of the pump-outlet tube and is configured to pump blood of a subject through the pump-outlet tube, such that the blood exits the pump-outlet tube through blood-outlet openings 109. In some applications, impeller 50 is self-expandable, e.g., by virtue of being made of a shape-memory alloy such as nitinol. Typically, an axial shaft 92, which passes through impeller 50 and to which the impeller is coupled, is rotated as described below. As axial shaft 92 is rotated, the impeller also rotates, thus pumping the blood of the subject.

[0091] Pump-outlet tube 24 is configured for insertion into the subject’s heart. Typically, blood pump 20 functions as a ventricular assist device for a ventricle of the heart.

[0092] For example, in some applications, pump-outlet tube 24 is inserted into the heart such that the pump-outlet tube spans the aortic valve of the subject, with distal portion 102 (and, optionally, some of proximal portion 106) of the pump-outlet tube positioned within the left ventricle and blood-outlet openings 109 positioned within the aorta. In some such applications, blood pump 20 assists the functioning of the left ventricle for a number of hours, such as for up to six or ten hours, e.g., during or immediately following a percutaneous coronary intervention, to reduce the risk of hemodynamic instability. Alternatively, the blood pump assists the functioning of the left ventricle for a number of days (e.g., 2-20 days), e.g., to stabilize a subject suffering from cardiogenic shock. Alternatively, the blood pump assists the functioning of the left ventricle for a longer period (e.g., several months), e.g., in a "bridge to recovery" treatment.

[0093] In other applications, the pump-outlet tube is inserted into the heart such that the pumpoutlet tube spans the pulmonary valve of the subject, with distal portion 102 (and, optionally, some of proximal portion 106) of the pump-outlet tube positioned within the right ventricle and bloodoutlet openings 109 positioned within the pulmonary trunk.

[0094] In some applications, proximal portion 106 includes a frustoconical proximal section 42 and a cylindrical distal section 44. Typically, in such applications, blood-outlet openings 109 are teardrop-shaped and extend at least partially along proximal section 42, such that the blood exits the pump-outlet tube, via the blood-outlet openings, along flow lines that are substantially parallel with the longitudinal axis of pump-outlet tube 24 at the location of the blood-outlet openings.

[0095] In some applications, pump 20 further includes a delivery tube 142 configured to extend, from outside the body of the subject, through the pump-outlet tube to the distal portion of the pump-outlet tube. In some such applications, proximal portion 106 includes a tubular coupling portion 45, via which the pump-outlet tube is coupled (e.g., via an adhesive) to delivery tube 142.

[0096] Typically, pump 20 includes a frame 34 coupled to the inner wall of distal portion 102 of pump-outlet tube 24. Frame 34 is configured to hold distal portion 102 open, e.g., such that distal portion 102 assumes a generally cylindrical shape. Typically, frame 34 is not coupled to proximal portion 106 of pump-outlet tube 24. Pump-outlet tube 24 is typically made of a blood-impermeable collapsible material, which in some applications includes polyurethane, polyester, silicone, polyethylene terephthalate, and / or polyether block amide (e.g., PEBAX®). Thus, typically, proximal portion 106 of pump-outlet tube 24 is held open only by the flow of blood therethrough.

[0097] Typically, frame 34 is self-expandable, e.g., by virtue of being made of a shape-memory alloy such as nitinol. By way of example, Fig. 1 shows a self-expandable frame including a proximal frustoconical portion 36, a central cylindrical portion 38, and a distal frustoconical portion 40.

[0098] In some applications, within at least a portion of frame 34 (e.g., along at least some of central cylindrical portion 38), an inner lining (not shown) lines the frame.

[0099] In some applications, pump 20 further includes a distal -tip element 107. In some such applications, distal-tip element 107 includes an axial-shaft-receiving tube 126 and a distal-tip portion 120. Axial-shaft-receiving tube 126 is configured to receive a distal portion of axial shaft 92 during axial back-and-forth motion of the axial shaft, and / or during the delivery of the blood pump to the heart. Typically, distal-tip portion 120 is configured to assume a curved shape upon being deployed within the subject's heart, e.g., as shown in Fig. 1. Typically, by virtue of the curvature of the distal-tip portion, the distal-tip portion functions as an atraumatic tip for blood pump 20. Alternatively or additionally, the distal-tip portion is configured to space blood-inlet openings 108 of the blood pump from cardiac tissue.

[0100] Pump 20 further includes a driven diametric magnet 52 coupled to impeller 50 such that the impeller rotates with driven diametric magnet 52. For example, typically, the driven diametric magnet is mounted onto axial shaft 92 or onto another shaft coupled, at its distal end, to the proximal end of shaft 92. Thus, as driven diametric magnet 52 rotates, the axial shaft, and hence the impeller, also rotate.

[0101] Typically, driven diametric magnet 52 is contained within a driven-magnet tube 64. Typically, driven-magnet tube 64 further contains a proximal bearing 72p and a distal bearing 72d, which center driven diametric magnet 52 within driven-magnet tube 64 such that the driven diametric magnet does not rub against the driven-magnet tube. Typically, proximal bearing 72p and distal bearing 72d also inhibit axial shaft 92 and impeller 50 from moving radially, such that axial shaft 92 does not require any additional radial bearings. In some applications, driven-magnet tube 64 further includes one or more axial bearings, which inhibit the driven diametric magnet from moving axially. Typically, proximal bearing 72p and / or distal bearing 72d also inhibit axial shaft 92 and impeller 50 from moving axially, thereby acting as thrust bearings (such that axial shaft 92 does not require any additional axial bearings). In some applications, the lack of any additional bearings helps obviate the need for pumping a purging fluid through the blood pump.

[0102] In some applications, as shown in Fig. 1, driven diametric magnet 52 is disposed within the pump-outlet tube. In other applications, the driven diametric magnet is proximal to the pumpoutlet tube.

[0103] Pump 20 further includes a driving diametric magnet 54 configured for positioning alongside driven diametric magnet 52 within the body of the subject, e.g., within the heart, aorta, or pulmonary trunk of the subject. The pump further includes a drive cable 130 coupled to driving diametric magnet 54. Typically, the driving diametric magnet is mounted onto drive cable 130 (e.g., onto a narrower distal portion of the drive cable) or onto another shaft coupled, at its proximal end, to the distal end of the drive cable. Drive cable 130 is configured to rotate driving diametric magnet 54, while the driving diametric magnet is alongside driven diametric magnet 52, such that the driving diametric magnet rotates the driven diametric magnet via magnetic coupling, thereby rotating impeller 50.

[0104] Typically, blood pump 20 further includes a sealed drive-cable-bearing tube 56 and a lubricant 58 (e.g., petroleum gel or high-density silicone) within drive-cable-bearing tube 56. In some applications, drive cable 130 passes through drive-cable-bearing tube 56 and is lubricated by lubricant 58. Typically, lubricant 58 obviates the need for pumping a purging fluid through the drive-cable-bearing tube while the drive cable rotates the driving diametric magnet. For some applications, lubricant (e.g., petroleum gel or high-density silicone) is also contained within driven-magnet tube 64, thereby lubricating the driven magnet , and / or proximal bearing and distal bearings 72p, 72d.

[0105] In some applications, driving diametric magnet 54 is disposed within the distal end of drive-cable-bearing tube 56. In other applications, as shown in Fig. 3, pump 20 further includes a driving-magnet tube 80 containing driving diametric magnet 54 and coupled to the distal end of drive-cable-bearing tube 56. Typically, a proximal bearing 60p and a distal bearing 60d center driving diametric magnet 54 within the tube that houses the driving magnet (i.e., within drive- cable-bearing tube 56 or driving-magnet tube 80) such that the driving diametric magnet does not rub against the tube. Furthermore, for applications in which the driving magnet is housed within drive-cable-bearing tube 56, proximal bearing 60p typically isolates the driving diametric magnet from lubricant 58.

[0106] In some applications, driven diametric magnet 52 is disposed within delivery tube 142, and the delivery tube is shaped to define an opening 62 that is at least partly proximal to the driven diametric magnet. Driving diametric magnet 54 is configured to advance through the body of the subject while disposed within delivery tube 142 proximally to driven diametric magnet 52, and to advance, subsequently, through opening 62 (e.g., by virtue of drive-cable-bearing tube 56 being advanced through delivery tube 142) until the driving diametric magnet is alongside the driven diametric magnet.

[0107] Typically, in such applications, blood pump 20 is shaped to define a guidewire lumen 66 passing from the proximal end of drive cable 130 at least to the distal end of pump-outlet tube 24, e.g., to the distal end of distal -tip element 107, and the blood pump is for use with a guidewire 68 passing through guidewire lumen 66. Driving diametric magnet 54 is configured to advance, through the body, over guidewire 68, and to advance through opening 62 following the withdrawal of the distal end of the guidewire to a position proximal to the driven diametric magnet, e.g., to a position within drive cable 130 or outside the body of the subject.

[0108] Further typically, in such applications, pump-outlet tube 24 is inserted into the subject’s heart, over guidewire 68, while disposed within the distal end of a sheath 78 that extends from outside the body of the subject to the heart, such that any self-expandable components (e.g., frame 34 and / or impeller 50) are radially constrained by the sheath. Following the positioning of the pump-outlet tube in the heart as required, the pump-outlet tube is deployed from sheath 78, such that the self-expandable components expand. Typically, to deploy the pump-outlet tube, sheath 78 is retracted while delivery tube 142 is held in place, the delivery tube is advanced while the sheath is held in place, or the sheath is retracted while the delivery tube is advanced. Similarly, to remove the blood pump from the subject’s heart, sheath 78 is advanced while delivery tube 142 is held in place, the delivery tube is retracted while the sheath is held in place, or the sheath is advanced while the delivery tube is retracted. Next, the guidewire is withdrawn, and the driving diametric magnet is then advanced through opening 62.

[0109] In some applications, at least for the reasons described above, blood pump 20 is configured for use without any purging fluid being pumped through any portion of the blood pump. In addition to reduced complexity and ease of operation, an advantage of this configuration is that the diameter of sheath 78 can be smaller than would be possible if the sheath were required to accommodate the flow of a purging fluid.

[0110] For applications in which the pump is inserted into the left ventricle, distal-tip element 107 is typically positioned at the apex of the left ventricle. For example, in some applications, distal -tip element 107 is positioned at the apex of the left ventricle by pushing the distal -tip element toward the apex while withdrawing the guidewire from the distal -tip element. If, on the other hand, the guidewire were withdrawn before pushing the distal-tip element toward the apex, it might be challenging to position the distal -tip element correctly. Likewise, if the guidewire were withdrawn after pushing the distal-tip element toward the apex, the withdrawal of the guidewire might cause the distal-tip element to become reshaped, which might also result in incorrect positioning.

[0111] In some applications, drive-cable-bearing tube 56 or driving-magnet tube 80 (Fig. 3) includes a rounded head 70 configured to guide the drive-cable-bearing tube or driving-magnet tube through opening 62 when rounded head 70 is pushed against driven-magnet tube 64. In such applications, typically, the proximal end of driven-magnet tube 64 is slightly proximal to the distal end of opening 62.

[0112] Alternatively or additionally, multiple steering wires (not shown) are coupled to the drive- cable-bearing tube or driving-magnet tube and are configured to steer the drive-cable-bearing tube or driving-magnet tube through the opening. Alternatively or additionally, an inflatable element 74 disposed within delivery tube 142 is configured to inflate, thereby pushing the driving diametric magnet through the opening (e.g., by virtue of pushing the drive-cable-bearing tube or drivingmagnet tube through the opening).

[0113] Reference is now made to Fig. 2, which is a schematic illustration of the two diametric magnets magnetically coupled to one another, in accordance with some applications of the present disclosure.

[0114] As driving diametric magnet 54 is positioned alongside driven diametric magnet 52, the two magnets become magnetically coupled to one another. Typically, as a result of the magnetic coupling, the driving magnet is pulled into the same orientation as that of the driven magnet, such that the two magnets are parallel to one another. Furthermore, as a result of the magnetic coupling, the rotation of the driving magnet drives rotation of the driven magnet.

[0115] Typically, the magnetic coupling is relatively strong, such that impeller 50 (Fig. 1) can be rotated relatively quickly and a relatively high flow rate of blood can be sustained. For example, in some applications, the two magnets are configured to remain magnetically coupled to one another even when the rotational speed of the driven diametric magnet and the driving diametric magnet is greater than 20,000 rotations per minute. Alternatively or additionally, the impeller and magnets are configured to sustain a rotational speed of the impeller of at least 20,000 rotations per minute, and / or a flow rate of the blood of at least three (e.g., at least five) liters per minute, for a mean pressure gradient between the aorta and the left ventricle of up to at least 60 mmHg.

[0116] Typically, to facilitate the magnetic coupling, the respective lengths of the two magnets are each at least 10 mm. For example, in some applications, the two magnets have an identical length that is at least 10 mm, e.g., that is between 10 and 30 mm, such as between 15 and 25 mm.

[0117] In some applications, the respective diameters of the two magnets are each less than 2.5 mm, e.g., less than 2.2 mm. For example, in some applications, the two magnets have an identical diameter that is less than 2.5 mm, e.g., less than 2.2 mm. Typically, the relatively small diameters of the magnets facilitate the insertion and positioning of the magnets. In this regard, it is noted that the driving magnet is typically inserted via an arterial insertion site (e.g., a femoral insertion site) separately from the driven magnet. Thus, the arterial insertion site does not need to accommodate the diameters of both of the magnets simultaneously. Drive cable 130 is coupled, at its proximal end, to a motor unit 23, which includes a motor 31. Typically, motor unit 23 is coupled to a control console 21 via a cable 229. Control console 21 includes a computer processor 25 configured to drive motor 31 to rotate drive cable 130.

[0118] Reference is now made to Fig. 3, which is a schematic illustration of blood pump 20 in accordance with other applications of the present disclosure.

[0119] In some applications, driving diametric magnet 54 is not placed into position alongside driven diametric magnet 52 as described with reference to Fig. 1. Rather, driving diametric magnet 54 advances through the body of the subject over a guide string 76 that extends from outside the body of the subject at least to the distal end of driven diametric magnet 52, until the driving diametric magnet is alongside the driven diametric magnet.

[0120] Typically, guide string 76 is coupled to frame 34. For example, in some applications, the distal end of the guide string is tied and / or welded to the frame. Alternatively, the guide string loops around the frame, such that both ends of the guide string remain outside the body of the subject.

[0121] For example, in some applications, driven diametric magnet 52 is disposed within pumpoutlet tube 24, and guide string 76 passes through one of blood-outlet openings 109. The driving magnet thus advances, via the blood-outlet opening, to a position alongside the driven magnet within the pump-outlet tube. In other applications, as described above with reference to Fig. 1, driven diametric magnet 52 is proximal to the blood-outlet tube.

[0122] In some applications, the distal end of the tube that houses the driving diametric magnet (i.e., drive-cable-bearing tube 56 or driving-magnet tube 80) includes a looped element 84, and driving diametric magnet 54 advances over guide string 76 by virtue of the guide string passing through looped element 84.

[0123] Typically, as further described below with reference to Figs. 4A-B, the blood pump is deployed using sheath 78, which is configured to extend from outside the body of the subject to the subject’s heart.

[0124] In some applications, blood pump 20 includes a push-pull rod 82 coupled to the proximal end of driven-magnet tube 64 and configured to extend from outside the body of the subject to the subject’s heart, e.g., by virtue of passing through sheath 78. Advantageously, push-pull rod 82 facilitates deploying the blood pump, as further described below with reference to Fig. 4B. In such applications, blood pump 20 does not necessarily include delivery tube 142 (Fig. 1). Typically, in such applications, guidewire lumen 66 passes from the proximal end of the push-pull rod at least to the distal end of the pump-outlet tube, e.g., to the distal end of distal-tip element 107. Blood pump 20 is configured for insertion into the subject’s heart over guidewire 68, which passes through guidewire lumen 66.

[0125] Reference is now made to Figs. 4A-F, which show a method for deploying blood pump 20 (configured as shown in Fig. 3), in accordance with some applications of the present disclosure.

[0126] As shown in Fig. 4A, pump-outlet tube 24 is configured for insertion into the subject’s heart while disposed within the distal end 78d of sheath 78, such that the sheath radially constrains any self-expandable components such as frame 34 and / or impeller 50. During the insertion of sheath 78 into the heart, guide string 76 passes from inside the sheath (e.g., from frame 34) through the distal end of the sheath, and from the distal end of the sheath, alongside the sheath, to the exterior of the subject’s body. To facilitate this curvature in the guide string, guide string 76 is typically more flexible than guidewire 68.

[0127] Following the positioning of the pump-outlet tube in the heart as required, the pump-outlet tube is deployed from sheath 78, as shown in Fig. 4B, such that any self-expandable components of the blood pump expand. Typically, to deploy the pump-outlet tube, sheath 78 is retracted while push-pull rod 82 is held in place, the push-pull rod is advanced while the sheath is held in place, or the sheath is retracted while the push-pull rod is advanced. Similarly, to remove the blood pump from the subject’s heart, sheath 78 is advanced while push-pull rod 82 is held in place, the push- pull rod is retracted while the sheath is held in place, or the sheath is advanced while the push-pull rod is retracted.

[0128] Next, guide string 76 is straightened, as shown in Fig. 4C.

[0129] Subsequently, in some applications, driving diametric magnet 54 is advanced, over the guide string, alongside sheath 78, as shown in Fig. 4D. Typically, the sum of the respective diameters of the proximal end of the sheath, which is configured to pass into the body of the subject (and via an arterial insertion site (e.g., a femoral insertion site)), and the tube that houses the driving diametric magnet (i.e., drive-cable-bearing tube 56 or driving-magnet tube 80) is less than 5 mm, e.g., less than 4 mm. Thus, advantageously, even though the driving magnet is inserted into the body (and via an arterial insertion site (e.g., a femoral insertion site)) alongside sheath 78, the opening into the body (and the arterial insertion site (e.g., the femoral insertion site)) can be relatively small. In some applications, to facilitate the small sum of diameters, a proximal portion 78p (Fig. 4A) of the sheath, which includes the proximal end of the sheath, is narrower than distal end 78d.

[0130] In other applications, sheath 78 is removed from the subject’s body before driving diametric magnet 54 is advanced over the guide string.

[0131] For applications in which driven diametric magnet 52 is within the pump-outlet tube, the driving diametric magnet is further advanced into the pump-outlet tube through a blood-outlet opening 109, as shown in Fig. 4E. Finally, the driving diametric magnet is positioned alongside the driven diametric magnet, as shown in Fig. 4F.

[0132] At any point in time following the deployment of pump-outlet tube 24, guidewire 68 is typically withdrawn from the subject’s body.

[0133] VENTRICULAR ASSIST DEVICE THAT IS INSERTED VIA AN UPPER-BODY AND / OR A FOREARM ARTERY

[0134] Reference is made to Fig. 5, which is a schematic illustration of a ventricular assist system

[0135] 210, which includes a ventricular assist device 220 (indicated in Fig. 6), also referred to as a “blood pump,” in accordance with some applications of the present disclosure. Reference is also made to Fig. 6, which shows a technique for deploying ventricular assist device 220, in accordance with some applications of the present disclosure, and to Fig. 7, which is a schematic illustration of a distal portion of ventricular assist device 220, referred to herein as a pump-head portion 227, in accordance with some applications of the present disclosure. It is noted that many aspects of ventricular assist device 220 and the functioning thereof are generally similar to that of ventricular assist device 220, described hereinabove.

[0136] Ventricular assist device 220 is configured for percutaneous insertion into an upper-body artery, such as a brachial artery 215, an axillary artery 216, a subclavian artery 217, or a forearm artery, such as a radial artery 212 or an ulnar artery 213, of a subject 243. Typically, the device is inserted into a right upper-body artery, e.g., into a right brachial, axillary, subclavian, or forearm (e.g., radial or ulnar) artery. Following the insertion, the device is advanced, via the upper-body artery, to the left ventricle 222 of the subject. For example, in some applications, as shown in Fig. 6, following the insertion of the device into a right forearm artery, the device is advanced to left ventricle 222 via the right brachial, axillary, and subclavian arteries, the brachiocephalic trunk

[0137] 211, and the ascending aorta 230, which is also referred to herein simply as the “aorta.” Pump-head portion 227 includes a pump-outlet tube 224, which is typically elongate, in that the axial length of the pump-outlet tube is typically substantially larger than its diameter. Pump-outlet tube 224 is shaped to define one or more (e.g., 2-8, such as 2-4) blood-outlet openings 309 at a proximal portion 306 of pump-outlet tube 224, typically near the proximal end 228 of the pump-outlet tube. Furthermore, the pump-outlet tube typically defines one or more blood-inlet openings 308 at a distal portion 302 of the tube, typically near or at the distal end 232 of the pumpoutlet tube. As shown in Fig. 7, in some applications, the pump-outlet tube defines a single axially- facing blood-inlet opening 308. Alternatively, as shown in Fig. 6, the pump-outlet tube defines a plurality of blood-inlet openings 308 facing laterally or obliquely with respect to the longitudinal axis of the pump-outlet tube. For example, in some applications, distal portion 302 includes a frustoconical end portion 247 that is shaped to define multiple (e.g., 2-4, 10-50, 50-100, or more than 100) blood-inlet openings 308.

[0138] As shown in Fig. 6, pump-outlet tube 224 is configured to span the aortic valve 226 of subject 243 such that distal portion 302 (and, optionally, some of proximal portion 306) of the pump-outlet tube is positioned within left ventricle 222 and blood-outlet openings 309 are positioned within aorta 230.

[0139] Pump-head portion 227 further includes an impeller 250, which is disposed within distal portion 302 of the pump-outlet tube. In some applications, impeller 250 is self-expandable, e.g., by virtue of being made of a shape-memory alloy such as nitinol. In other applications, as described below with reference to Fig. 10, impeller 250 is inflatable.

[0140] Device 220 further includes a delivery tube 342 configured to extend, from outside the body of the subject, through the pump-outlet tube to the distal portion of the pump-outlet tube. Device 220 further includes a drive cable 330 passing through delivery tube 342 and coupled to impeller 250 such that drive cable 330 is configured to rotate the impeller.

[0141] System 210 further includes a control console 221, including a processor 225, and a motor unit 223, which includes a motor 231. Processor 225 is configured to drive motor 231, e.g., via a cable 424, to rotate drive cable 330, thereby rotating impeller 250. The rotation of impeller 250 causes the impeller to pump blood into the pump-outlet tube via blood-inlet openings 308, through the pump-outlet tube, and out of the pump-outlet tube (and into aorta 230) via blood-outlet openings 309. In some applications, drive cable 330 is directly coupled to impeller 250. In other applications, the drive cable is coupled to the impeller (and is configured to rotate the impeller) via an axial shaft 292, which passes through impeller 250 and to which the impeller is coupled.

[0142] In some applications, proximal portion 306 includes a frustoconical proximal section 242 and a cylindrical distal section 244. Typically, in such applications, blood-outlet openings 309 are teardrop-shaped and extend at least partially along proximal section 242, such that the blood exits the pump-outlet tube, via the blood-outlet openings, along flow lines that are substantially parallel with the longitudinal axis of pump-outlet tube 224 at the location of the blood-outlet openings.

[0143] Alternatively or additionally, proximal portion 306 includes a tubular coupling portion 245, via which the pump-outlet tube is coupled (e.g., via an adhesive) to delivery tube 342.

[0144] Device 220 further includes a frame 234 coupled to the distal portion 302 of pump-outlet tube 224. Frame 234 is configured to hold distal portion 302 open, e.g., such that distal portion 302 assumes a generally cylindrical shape. Typically, frame 234 is not coupled to proximal portion 306 of pump-outlet tube 224. Pump-outlet tube 224 is typically made of a blood-impermeable collapsible material, which in some applications includes polyurethane, polyester, silicone, polyethylene terephthalate (PET), and / or polyether block amide (e.g., PEBAX®). Thus, typically, proximal portion 306 of pump-outlet tube 224 is held open only by the flow of blood therethrough.

[0145] Typically, pump-head portion 227 further includes a distal-tip element 307. Typically, distal-tip element 307 is positioned at the apex of the left ventricle.

[0146] In some such applications, distal-tip element 307 includes an axial-shaft-receiving tube 326 and a distal-tip portion 320. Axial-shaft-receiving tube 326 is configured to receive a distal portion of axial shaft 292 during axial back-and-forth motion of the axial shaft, and / or during the delivery of the ventricular assist device. Typically, distal-tip portion 320 is configured to assume a curved shape upon being deployed within the subject's left ventricle, e.g., as shown in Fig. 7. Typically, by virtue of the curvature of the distal-tip portion, the distal-tip portion functions as an atraumatic tip for ventricular assist device 220. Alternatively or additionally, the distal-tip portion is configured to space blood-inlet openings 308 of the ventricular assist device from walls of the left ventricle.

[0147] As further described below with reference to Fig. 10, in some applications, device 220 is guided to the left ventricle, and inserted into the left ventricle, over a guidewire, such as a standard 0.018 inch (0.46 mm) guidewire. In such applications, drive cable 330 and distal-tip element 307 are shaped to define a guidewire lumen through which the guidewire is passed. Typically, the guidewire includes a soft atraumatic distal end.

[0148] In some applications, a fluid (e.g., a glucose solution) is pumped through portions of ventricular assist device 220. The fluid cools portions of the device, purges and / or lubricates interfaces between rotating parts and stationary bearings, and / or washes away debris. For example, in some applications, the fluid is pumped into the device, from a purging-fluid bag 398, via an inlet port 286, and from the device, into a waste bag 400, via an outlet port 288. Alternatively, no fluid is pumped through the device. In such applications, the diameter of the device can be reduced, relative to the alternative applications described above.

[0149] In some applications, frame 234 is self-expandable, e.g., by virtue of being made of a shape-memory alloy such as nitinol. By way of example, Fig. 7 shows a self-expandable frame including a proximal frustoconical portion 236, a central cylindrical portion 238, and a distal frustoconical portion 240.

[0150] In such applications, typically, frame 234 is coupled to the inner wall of distal portion 302. Optionally, within at least a portion of frame 234 (e.g., along at least some of central cylindrical portion 238), an inner lining (not shown) lines the frame.

[0151] In other applications, as described below with reference to Fig. 10, frame 234 is inflatable. In such applications, typically, frame 234 is coupled to the outer wall of distal portion 302.

[0152] In some applications, pump-head portion 227 of ventricular assist device 220 is delivered to the left ventricle via a sheath 214. Once pump-outlet tube is positioned such that it spans aortic valve 226 as described above, the pump-outlet tube and frame are deployed from the sheath. Subsequently to the deployment, the sheath is withdrawn from the heart, as shown in Fig. 6. For example, in some applications, the distal end of the sheath is withdrawn into brachiocephalic trunk 211, where the distal end of the sheath remains while the impeller pumps the blood of the subject. In some such applications, a pressure sensor 406 is connected, via a pressure-sensing tube 379 of device 220, to a pressure-sensing channel 347 passing between sheath 214 and delivery tube 342. Pressure sensor 406 is configured to measure the pressure in pressure-sensing channel 347, which is equivalent to the pressure within aorta 230, and to output the measured pressure to processor 225. Typically, a flushing-fluid bag 402 contains a flushing fluid (e.g., saline) for flushing aortic pressure-sensing channel 347 via pressure-sensing tube 379. For applications in which impeller 250 and / or frame 234 is self-expandable, sheath 214 radially constrains the impeller and / or frame while the device is advanced through the sheath. Subsequently, the impeller and / or frame expands, within the left ventricle, upon exiting the sheath.

[0153] Typically, console 221 further includes a display 428, on which processor 225 may display various outputs, such as the intra-aortic pressure.

[0154] In some applications, the blood pump assists the functioning of the left ventricle for a number of hours, such as for up to six or ten hours, e.g., during or immediately following a percutaneous coronary intervention, to reduce the risk of hemodynamic instability. Alternatively, the blood pump assists the functioning of the left ventricle for a number of days (e.g., 2-20 days), e.g., to stabilize a subject suffering from cardiogenic shock. Alternatively, the blood pump assists the functioning of the left ventricle for a longer period (e.g., several weeks or months), e.g., in a "bridge to recovery" treatment.

[0155] An advantage of inserting the device into an upper-body artery, rather than a lower-body artery (e.g., a femoral artery), is greater mobility of subject 243. This advantage is important, for example, in cases in which the device is used for a longer period of time. Another advantage is less curvature in the arteries between the point of insertion and the left ventricle, such that the device can be advanced to the left ventricle, through sheath 214, without being guided by a guidewire, as further described below with reference to Fig. 8.

[0156] In other applications, device 220 assists the functioning of the subject’s right ventricle. In such applications, pump-outlet tube 224 spans the pulmonary valve of the subject, with distal portion 302 (and, optionally, some of proximal portion 306) of the pump-outlet tube positioned within the right ventricle and blood-outlet openings 309 positioned within the pulmonary trunk. Typically, the percutaneous insertion is made in an upper-body vein of the subject, such as a brachial, axillary, subclavian, or forearm (e.g., radial or ulnar) vein. Typically, the upper-body vein is a right upper-body vein.

[0157] Typically, the upper-body and forearm arteries are relatively narrow. Nevertheless, advantageously, the ventricular assist device can be configured to have a relatively small diameter, such that the device can be inserted into the heart even via an upper-body and / or a forearm artery.

[0158] For example, in some applications, the device is not advanced to the left ventricle by being guided by a guidewire, but rather, is merely advanced through sheath 214, such that accommodation of the diameter of the guidewire is obviated. For example, drive cable 330 need not be shaped to define a guidewire lumen, such that the drive cable - and hence the delivery tube, frame, and sheath - can have a smaller diameter than would otherwise be possible. Typically, in such applications, to facilitate the smaller diameter of the sheath, the device is advanced through the sheath without any tubular structure, such as a catheter, interposing between the delivery tube and the sheath.

[0159] For example, in some applications, by virtue of omitting a guidewire, the outer diameter of the drive cable is less than 1.2 mm, the outer diameter of the delivery tube is less than 2.2 mm, and / or the outer diameter of the sheath is less than 2.8 mm. As a specific example, in some applications, sheath 214 is a 7 Fr or 6 Fr sheath.

[0160] In this regard, reference is now made to Fig. 8, which is a flow diagram for a method 310 for positioning ventricular assist device 220 within the body of subject 243 (Fig. 5), in accordance with some applications of the present disclosure. Reference is also made to Figs. 9A-K, which show steps in method 310, in accordance with some applications of the present disclosure.

[0161] Method 310 begins with the percutaneous insertion of sheath 214 (Fig. 5) into an upperbody artery, such as a forearm artery, of the subject. Typically, the insertion of the sheath begins with the insertion of a guidewire 252 (Fig. 9A), such as a 0.035 inch (0.89 mm) guidewire, into the artery at an insertion site 254, at a guidewire-inserting step 312. Following the insertion of guidewire 252, sheath 214 is inserted, with a dilator 256 (Fig. 9B), over the guidewire into the artery, at a sheath-inserting step 314.

[0162] Next, the sheath is advanced, via the upper-body artery, into left ventricle 222 (Fig. 6) of the subject. Typically, prior to advancing the sheath, at a dilator-extracting step 316, dilator 256 is extracted and a pigtail catheter 258 (Fig. 9C) is inserted into the artery. Next, at a guidewireadvancing step 318, guidewire 252, pigtail catheter 258, and sheath 214 are advanced to aortic valve 226, as shown in Fig. 9D. The aortic valve is then crossed, with the guidewire and pigtail catheter, at a valve-crossing step 319, as shown in Fig. 9E. Finally, at a sheath-advancing step 322, the sheath is advanced over the guidewire into left ventricle 222, as shown in Fig. 9F.

[0163] Following the insertion of the sheath into the left ventricle, the guidewire and pigtail catheter are withdrawn from the body of the subject, at a guidewire-withdrawing step 324, as shown in Fig. 9G. As shown in Figs. 9H-I, ventricular assist device 220 is then advanced through the sheath (and not over a guidewire), at a device-advancing step 325, until pump-outlet tube 224 is properly positioned, i.e., until the pump-outlet tube spans the aortic valve such that distal portion 302 of the pump-outlet tube is positioned within the left ventricle and blood-outlet openings 309 are positioned within the aorta. Finally, the pump-outlet tube and frame 234 (Fig. 7) are deployed from the sheath at a deploying step 328. Fig. 9J shows the pump-outlet tube partly deployed, in that the sheath is partly withdrawn from over the pump-outlet tube. Fig. 9K shows the pump-outlet tube fully deployed. As described above with reference to Fig. 6 and shown in Fig. 9K, in some applications, following the deployment, the distal end of the sheath is positioned in brachiocephalic trunk 211.

[0164] Reference is now made to Fig. 10, which is a schematic illustration of frame 234 and distal portion 302 of pump-outlet tube 224, in accordance with some applications of the present disclosure.

[0165] In some applications, frame 234 is inflatable, and is coupled to the outer wall of distal portion 302 of pump-outlet tube 224. As described above with reference to Fig. 7, impeller 250 is disposed within the distal portion of the pump-outlet tube and is configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the bloodoutlet openings 309. Delivery tube 342 is configured to extend from outside the body of the subject, via an upper-body artery (e.g., a forearm artery) of the subject, through the pump-outlet tube, and drive cable 330 passes through the delivery tube and is coupled to the impeller such that the drive cable is configured to rotate the impeller. The ventricular assist device is advanced via the upper-body artery, while the frame is deflated, until the pump-outlet tube spans the aortic valve such that the blood-outlet openings are positioned within the aorta and the distal portion of the pump-outlet tube is positioned within the left ventricle. Subsequently, the frame is inflated within the left ventricle.

[0166] In some such applications, the device is advanced through sheath 214 (Fig. 5), e.g., as described above with reference to Fig. 8. Following the deployment of the frame from the sheath, the frame is inflated within the left ventricle. In such applications, typically, the drive cable is not shaped to define a guidewire lumen, and the frame and pump-outlet tube are not delivered over a guidewire.

[0167] An advantage of an inflatable frame is that the outer diameter of the frame, while the frame is deflated, is typically smaller than that of a radially-constrained self-expandable frame. For example, in some applications, the outer diameter of the frame, while the frame is deflated, is less than 2.4 mm. Advantageously, for applications in which sheath 214 is used for the delivery of the device to the heart, the smaller diameter of the frame facilitates a smaller diameter of the sheath, such that the sheath can be more easily inserted into a forearm artery of the subject. Typically, also facilitating the smaller sheath diameter is the lack of any tubular structure interposing between the delivery tube and the sheath. For example, in some applications, the outer diameter of the sheath is less than 2.8 mm, e.g., the sheath is a 7 Fr or 6 Fr sheath.

[0168] In some applications, frame 234 includes multiple inflatable rings 348 surrounding pumpoutlet tube 224 and arranged along the longitudinal axis of the pump-outlet tube. Advantageously, such a configuration provides greater consistency in the diameter of the frame, relative to if the frame were to include a single, cylindrical inflatable element.

[0169] In some such applications, frame 234 further includes multiple inflatable tubes 350 that pass between rings 348 along the longitudinal axis of the pump-outlet tube and establish fluid communication between the rings. Advantageously, tubes 350, upon their inflation, axially expand the pump-outlet tube. Furthermore, by virtue of the fluid communication, all of rings 348 and tubes 350 can be simultaneously inflated using the same inflation channel(s). Alternatively, these advantages are provided by arranging rings 348 in contact with each other, with one or more openings between each pair of adjacent rings.

[0170] In some applications, the impeller is also inflatable, and is inflated within the left ventricle. An advantage of an inflatable impeller is that the outer diameter of the impeller, while the impeller is deflated, is typically smaller than that of a radially-constrained self-expandable impeller. For example, in some applications, the outer diameter of the impeller, while the impeller is deflated, is less than 2.2 mm.

[0171] An advantage of both the frame and the impeller being inflatable is that no element of the device requires radial constraint during the delivery to the left ventricle. Hence, for some applications in which both the frame and the impeller are inflatable, the drive cable is shaped to define a guidewire lumen, and the device is advanced, while the frame and impeller are deflated, over a guidewire passing through the guidewire lumen, without any tubular structure, such as a sheath, interposing between the device and the subject’s upper-body arteries.

[0172] It will be appreciated by persons skilled in the art that the present disclosure is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

CLAIMS1. An apparatus, comprising: a blood pump, comprising: a pump-outlet tube shaped to define one or more blood-outlet openings and configured for insertion into a heart of a subject; an impeller configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube through the blood-outlet openings; a driven diametric magnet coupled to the impeller such that the impeller rotates with the driven diametric magnet; a driving diametric magnet configured for positioning alongside the driven diametric magnet within a body of the subject; and a drive cable coupled to the driving diametric magnet and configured to rotate the driving diametric magnet, while the driving diametric magnet is alongside the driven diametric magnet, such that the driving diametric magnet rotates the driven diametric magnet via magnetic coupling, thereby rotating the impeller.

2. The apparatus according to claim 1, wherein each one of respective lengths of the driven diametric magnet and the driving diametric magnet is at least 10 mm.

3. The apparatus according to claim 1 , wherein each one of respective diameters of the driven diametric magnet and the driving diametric magnet is less than 2.5 mm.

4. The apparatus according to claim 1, wherein the driven diametric magnet and the driving diametric magnet are configured to remain magnetically coupled to one another even when a rotational speed of the driven diametric magnet and the driving diametric magnet is greater than 20,000 rotations per minute.

5. The apparatus according to claim 1, wherein the blood pump is configured for use without any purging fluid being pumped through any portion of the blood pump.

6. The apparatus according to claim 1, wherein the driven diametric magnet is disposed within the pump-outlet tube.

7. The apparatus according to claim 1, wherein the driven diametric magnet is proximal to the pump-outlet tube.

8. The apparatus according to claim 1, wherein the pump-outlet tube is configured for insertion into the subject’s heart such that a distal portion of the pump-outlet tube is within a leftventricle of the subject’s heart and the blood-outlet openings are within an aorta of the subject.

9. The apparatus according to claim 8, wherein the impeller, driven diametric magnet, and driving diametric magnet are configured to sustain a rotational speed of the impeller of at least 20,000 rotations per minute for a mean pressure gradient between the aorta and the left ventricle of up to at least 60 mmHg.

10. The apparatus according to claim 8, wherein the impeller, driven diametric magnet, and driving diametric magnet are configured to sustain a flow rate of the blood of at least three liters per minute for a mean pressure gradient between the aorta and the left ventricle of up to at least 60 mmHg.

11. The apparatus according to any one of claims 1-10, wherein the blood pump further comprises: a sealed drive-cable-bearing tube; and a lubricant within the drive-cable-bearing tube, wherein the drive cable passes through the drive-cable-bearing tube and is lubricated by the lubricant.

12. The apparatus according to claim 11, wherein the lubricant obviates a need for pumping a purging fluid through the drive-cable-bearing tube while the drive cable rotates the driving diametric magnet.

13. The apparatus according to claim 11, wherein the driving diametric magnet is disposed within a distal end of the drive-cable-bearing tube.

14. The apparatus according to claim 11, wherein the blood pump further comprises a drivingmagnet tube containing the driving diametric magnet and coupled to a distal end of the drive- cable-bearing tube.

15. The apparatus according to any one of claims 1-10, wherein the blood pump further comprises a delivery tube configured to extend, from outside the body of the subject, through the pump-outlet tube to a distal portion of the pump-outlet tube, wherein the driven diametric magnet is disposed within the delivery tube, wherein the delivery tube is shaped to define an opening that is at least partly proximal to the driven diametric magnet, and wherein the driving diametric magnet is configured to: advance through the body of the subject while disposed within the delivery tubeproximally to the driven diametric magnet, and subsequently, advance through the opening until the driving diametric magnet is alongside the driven diametric magnet.

16. The apparatus according to claim 15, wherein the blood pump further comprises: a driven-magnet tube containing the driven diametric magnet; and another tube containing the driving diametric magnet and comprising a rounded head configured to guide the other tube through the opening when the rounded head is pushed against the driven-magnet tube.

17. The apparatus according to claim 15, wherein the blood pump further comprises: another tube containing the driving diametric magnet; and multiple steering wires coupled to the other tube and configured to steer the other tube through the opening.

18. The apparatus according to claim 15, wherein the blood pump further comprises an inflatable element disposed within the delivery tube and configured to inflate, thereby pushing the driving diametric magnet through the opening.

19. The apparatus according to claim 15, wherein the blood pump is shaped to define a guidewire lumen passing from a proximal end of the drive cable at least to a distal end of the pump-outlet tube, wherein the blood pump is for use with a guidewire passing through the guidewire lumen, wherein the driving diametric magnet is configured to advance, through the body, over the guidewire, and wherein the driving diametric magnet is configured to advance through the opening following a withdrawal of a distal end of the guidewire to a position proximal to the driven diametric magnet.

20. The apparatus according to any one of claims 1-10, further comprising a guide string configured to extend from outside the body of the subject at least to a distal end of the driven diametric magnet, wherein the driving diametric magnet is configured to advance, over the guide string, through the body of the subject until the driving diametric magnet is alongside the driven diametric magnet.

21. The apparatus according to claim 20, wherein the driven diametric magnet is disposed within the pump-outlet tube, andwherein the guide string passes through one of the blood-outlet openings.

22. The apparatus according to claim 20, wherein the blood pump further comprises an expandable frame surrounding the impeller within the pump-outlet tube, and wherein the guide string is coupled to the frame.

23. The apparatus according to claim 20, further comprising a sheath configured to extend from outside the body of the subject to the subject’s heart, wherein the pump-outlet tube is configured for insertion into the subject’s heart while disposed within a distal end of the sheath, and wherein the driving diametric magnet is configured to advance, over the guide string, alongside the sheath.

24. The apparatus according to claim 23, wherein the blood pump further comprises another tube containing the driving diametric magnet and configured to advance over the guide string, and wherein a sum of respective diameters of a proximal end of the sheath, which is configured to pass into the body of the subject, and the other tube is less than 5 mm.

25. The apparatus according to claim 20, wherein the blood pump further comprises: a driven-magnet tube containing the driven diametric magnet; and a push-pull rod coupled to a proximal end of the driven-magnet tube and configured to extend from outside the body of the subject to the subject’s heart.

26. The apparatus according to claim 25, wherein the blood pump is shaped to define a guidewire lumen passing from a proximal end of the push-pull rod at least to a distal end of the pump-outlet tube, wherein the blood pump is for use with a guidewire passing through the guidewire lumen, and wherein the pump-outlet tube is configured for insertion into the subject’s over the guidewire.

27. The apparatus according to claim 26, wherein the guide string is more flexible than the guidewire.

28. A method for positioning, within a body of a subject, an apparatus that includes: a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube,a frame coupled to a distal portion of the pump-outlet tube, an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings, a delivery tube configured to extend, from outside the body of the subject, through the pump-outlet tube, and a drive cable passing through the delivery tube and coupled to the impeller such that the drive cable is configured to rotate the impeller, the method comprising: percutaneously inserting a sheath into an upper-body artery of a subject; advancing the sheath, via the upper-body artery, into a left ventricle of the subject; advancing the apparatus, through the sheath and without the apparatus being guided by a guidewire, until the pump-outlet tube spans an aortic valve of the subject such that the distal portion of the pump-outlet tube is positioned within the left ventricle and the bloodoutlet openings are positioned within an aorta of the subject; and deploying the pump-outlet tube and the frame from the sheath.

29. The method according to claim 28, wherein the upper-body artery is selected from the group of arteries consisting of: a brachial artery, an axillary artery, and a subclavian artery.

30. The method according to claim 28, wherein the upper-body artery is a forearm artery of a forearm of the subject.

31. The method according to claim 30, wherein the forearm artery is a radial artery or an ulnar artery of the subject.

32. The method according to claim 30, wherein the forearm is a right forearm of the subject.

33. The method according to claim 28, wherein advancing the apparatus through the sheath comprises advancing the apparatus through the sheath without any tubular structure interposing between the delivery tube and the sheath.

34. The method according to claim 28, wherein the frame is self-expandable, wherein advancing the apparatus through the sheath comprises advancing the apparatus through the sheath while the frame is radially constrained by the sheath, and wherein deploying the frame from the sheath comprises causing the frame to expand, within the left ventricle, upon exiting the sheath.

35. The method according to claim 28, wherein the frame is coupled to an outer wall of the distal portion of the pump-outlet tube and is inflatable, wherein advancing the apparatus through the sheath comprises advancing the apparatus through the sheath while the frame is deflated, and wherein the method further comprises, subsequently to deploying the frame from the sheath, inflating the frame.

36. The method according to claim 35, wherein an outer diameter of the frame, while the frame is deflated, is less than 2.4 mm.

37. The method according to claim 28, wherein the drive cable is not shaped to define a guidewire lumen.

38. The method according to claim 28, wherein an outer diameter of the drive cable is less than 1.2 mm.

39. The method according to claim 28, wherein an outer diameter of the delivery tube is less than 2.2 mm.

40. The method according to any one of claims 28-39, further comprising, subsequently to deploying the pump-outlet tube and the frame from the sheath, withdrawing a distal end of the sheath into a brachiocephalic trunk of the subject such that the distal end of the sheath remains in the brachiocephalic trunk while the impeller pumps the blood.

41. The method according to claim 40, further comprising measuring an aortic pressure of the subject, while the distal end of the sheath is in the brachiocephalic trunk, using a pressure sensor connected to a channel between the sheath and the delivery tube.

42. The method according to any one of claims 28-39, wherein an outer diameter of the sheath is less than 2.8 mm.

43. The method according to claim 42, wherein the sheath is a 7 Fr sheath.

44. The method according to claim 42, wherein the sheath is a 6 Fr sheath.

45. An apparatus for use with a sheath percutaneously inserted into an upper-body artery of a subject, the apparatus comprising: a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube and configured to advance through the sheath without being guidedby a guidewire, while the sheath passes, via the upper-body artery, into a left ventricle of the subject, until the pump-outlet tube spans an aortic valve of the subject such that a distal portion of the pump-outlet tube is positioned within the left ventricle and the blood-outlet openings are positioned within an aorta of the subject; a frame coupled to the distal portion of the pump-outlet tube and configured for deployment from the sheath, together with the pump-outlet tube, subsequently to advancing through the sheath; an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings; a delivery tube configured to extend, from outside a body of the subject, through the pumpoutlet tube; and a drive cable, which passes through the delivery tube, is not shaped to define a guidewire lumen, and is coupled to the impeller such that the drive cable is configured to rotate the impeller.

46. The apparatus according to claim 45, wherein the upper-body artery is selected from the group of arteries consisting of: a brachial artery, an axillary artery, and a subclavian artery.

47. The apparatus according to claim 45, wherein the upper-body artery is a forearm artery of a forearm of the subject.

48. The apparatus according to claim 47, wherein the forearm artery is a radial artery or an ulnar artery of the subject.

49. The apparatus according to claim 47, wherein the forearm is a right forearm of the subject.

50. The apparatus according to claim 45, wherein the frame is self-expandable, such that the frame is configured to advance through the sheath while being radially constrained by the sheath, and to expand, within the left ventricle, upon the deployment from the sheath.

51. The apparatus according to claim 45, wherein the frame is coupled to an outer wall of the distal portion of the pump-outlet tube and is inflatable, such that the frame is configured to advance through the sheath while deflated, and is configured for inflation, within the left ventricle, subsequently to the deployment from the sheath.

52. The apparatus according to claim 51, wherein an outer diameter of the frame, while the frame is deflated, is less than 2.4 mm.

53. The apparatus according to claim 45, wherein an outer diameter of the drive cable is lessthan 1.2 mm.

54. The apparatus according to claim 45, wherein an outer diameter of the delivery tube is less than 2.2 mm.

55. The apparatus according to any one of claims 45-54, further comprising the sheath, wherein the sheath is configured to withdraw through the aorta until a distal end of the sheath is positioned within a brachiocephalic trunk of the subject, and wherein the distal end of the sheath is configured to remain in the brachiocephalic trunk while the impeller pumps the blood.

56. The apparatus according to claim 55, further comprising a pressure sensor connected to a channel between the sheath and the delivery tube and configured to measure an aortic pressure of the subject while the distal end of the sheath is in the brachiocephalic trunk.

57. The apparatus according to claim 55, wherein an outer diameter of the sheath is less than 2.8 mm.

58. The apparatus according to claim 57, wherein the sheath is a 7 Fr sheath.

59. The apparatus according to claim 57, wherein the sheath is a 6 Fr sheath.

60. An apparatus, comprising: a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube and configured to span an aortic valve of a subject such that the blood-outlet openings are positioned within an aorta of the subject and a distal portion of the pumpoutlet tube is positioned within a left ventricle of the subject; an inflatable frame coupled to an outer wall of the distal portion of the pump-outlet tube and configured to inflate within the left ventricle; an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings; a delivery tube configured to extend from outside a body of the subject, via a forearm artery of the subject, through the pump-outlet tube; and a drive cable, which passes through the delivery tube and is coupled to the impeller such that the drive cable is configured to rotate the impeller.

61. The apparatus according to claim 60, wherein the forearm artery is a radial artery or an ulnar artery of the subject.

62. The apparatus according to claim 60, wherein the forearm is a right forearm of the subject.

63. The apparatus according to claim 60, wherein an outer diameter of the frame, while the frame is deflated, is less than 2.4 mm.

64. The apparatus according to any one of claims 60-63, wherein the frame comprises multiple inflatable rings surrounding the pump-outlet tube and arranged along a longitudinal axis of the pump-outlet tube.

65. The apparatus according to claim 64, wherein the frame further comprises multiple inflatable tubes that pass between the rings along the longitudinal axis and establish fluid communication between the rings.

66. The apparatus according to any one of claims 60-63, wherein the impeller is inflatable, and is configured to inflate within the left ventricle.

67. The apparatus according to claim 66, wherein an outer diameter of the impeller, while the impeller is deflated, is less than 2.2 mm.

68. The apparatus according to claim 66, wherein the drive cable is shaped to define a guidewire lumen, and wherein the pump-outlet tube is configured to advance, to the aortic valve, over a guidewire passing through the guidewire lumen.

69. The apparatus according to any one of claims 60-63, wherein the drive cable is not shaped to define a guidewire lumen, wherein the apparatus is for use with a sheath that passes, via the forearm artery, into the left ventricle, and wherein the pump-outlet tube is configured to advance, to the aortic valve, through the sheath.

70. The apparatus according to claim 69, further comprising the sheath, wherein an outer diameter of the sheath is less than 2.8 mm.

71. The apparatus according to claim 70, wherein the sheath is a 7 Fr sheath.

72. The apparatus according to claim 70, wherein the sheath is a 6 Fr sheath.

73. A method for positioning, within a body of a subject, an apparatus that includes: a pump-outlet tube shaped to define one or more blood-outlet openings at a proximal portion of the pump-outlet tube, an inflatable frame coupled to an outer wall of a distal portion of the pump-outlet tube,an impeller disposed within the distal portion of the pump-outlet tube and configured to pump blood of the subject through the pump-outlet tube, such that the blood exits the pump-outlet tube via the blood-outlet openings, a delivery tube configured to extend, from outside a body of the subject, through the pumpoutlet tube, and a drive cable, which passes through the delivery tube and is coupled to the impeller such that the drive cable is configured to rotate the impeller, the method comprising: advancing the apparatus through a forearm artery of the subject, while the frame is deflated, until the pump-outlet tube spans an aortic valve of the subject such that the bloodoutlet openings are positioned within an aorta of the subject and the distal portion of the pump-outlet tube is positioned within a left ventricle of the subject; and inflating the frame within the left ventricle.

74. The method according to claim 73, wherein the forearm artery is a radial artery or an ulnar artery of the subject.

75. The method according to claim 73, wherein the forearm is a right forearm of the subject.

76. The method according to claim 73, wherein an outer diameter of the frame, while the frame is deflated, is less than 2.4 mm.

77. The method according to any one of claims 73-76, wherein the frame includes multiple inflatable rings surrounding the pump-outlet tube and arranged along a longitudinal axis of the pump-outlet tube, and wherein inflating the frame comprises inflating the rings.

78. The method according to claim 77, wherein the frame further includes multiple inflatable tubes that pass between the rings along the longitudinal axis and establish fluid communication between the rings, and wherein inflating the frame comprises inflating the tubes.

79. The method according to any one of claims 73-76, wherein the impeller is inflatable, and wherein the method further comprises inflating the impeller within the left ventricle.

80. The method according to claim 79, wherein an outer diameter of the impeller, while the impeller is deflated, is less than 2.2 mm.

81. The method according to claim 79, wherein the drive cable is shaped to define a guidewire lumen, and wherein advancing the apparatus comprises advancing the apparatus over a guidewire passing through the guidewire lumen, without any tubular structure interposing between theapparatus and the forearm artery.

82. The method according to any one of claims 73-76, wherein the drive cable is not shaped to define a guidewire lumen, and wherein the method further comprises inserting a sheath, via the forearm artery of the subject, into the left ventricle of the subject, wherein advancing the apparatus comprises advancing the apparatus through the sheath, and wherein the method further comprises, prior to inflating the frame, deploying the pumpoutlet tube and the frame from the sheath.

83. The method according to claim 82, wherein an outer diameter of the sheath is less than 2.8 mm.

84. The method according to claim 83, wherein the sheath is a 7 Fr sheath.

85. The method according to claim 83, wherein the sheath is a 6 Fr sheath.

86. The method according to claim 82, wherein advancing the apparatus through the sheath comprises advancing the apparatus through the sheath without any tubular structure interposing between the delivery tube and the sheath.

Images