Blood pump

Abstract

To provide a device and a method used in conjunction with an object venous system including one or more branch blood vessels flowing into a vein at a junction.SOLUTION: A blood pump catheter (70) includes a material (36) configured to be installed in a downstream position downstream of a junction, and to close a blood flow that is flowing in a vein at least partially. The material defines a blood outlet opening (31). A blood pump (24) pumps the blood from a region of the vein adjacent to the junction through the blood outlet opening (31). A blood flow route (60) guides an upstream venous blood flow toward downstream of the material (36) from an upstream position upstream of the junction without pumping it by the pump (24). Other applications are also described.SELECTED DRAWING: Figure 2E

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority from the following: U.S. Provisional Patent Application No. 62 / 851,769 to Friedland, entitled “Blood pumps,” filed May 23, 2019. U.S. Provisional Patent Application No. 62 / 870,822 to Friedland, entitled “Blood pumps,” filed July 5, 2019. U.S. Provisional Patent Application No. 62 / 890,177 to Friedland, entitled “Blood pumps,” filed Aug. 22, 2019. U.S. Provisional Patent Application No. 62 / 983,786 to Friedland, entitled “Blood pumps,” filed March 2, 2020.

[0002] Each of the above referenced applications is incorporated herein by reference.

[0003] Some applications of the present invention relate generally to medical devices, and more particularly to devices and methods associated with placing a pump in a vein or artery. [Background technology]

[0004] It is common for cardiac dysfunction or congestive heart failure to progress to renal dysfunction, thereby causing or aggravating symptoms of congestive heart failure. Typically, systolic and / or diastolic cardiac dysfunction causes congestion of systemic veins, which results in increased renal venous and interstitial pressures. The increased pressure increases fluid retention by the body, typically due to both renal dysfunction and renal neurohormonal activation resulting from increased renal venous and interstitial pressures. The resulting fluid retention causes or aggravates congestive heart failure by causing volume overload in the heart and / or increasing systemic resistance. Similarly, it is common for renal dysfunction and / or renal neurohormonal activation to progress to cardiac dysfunction and / or congestive heart failure. This pathophysiological cycle in which cardiac dysfunction and / or congestive heart failure leads to renal dysfunction and / or renal neurohormonal activation, or renal dysfunction and / or renal neurohormonal activation leads to cardiac dysfunction and / or congestive heart failure, with each dysfunction exacerbating the other, is referred to as the cardiorenal syndrome.

[0005] Increased renal venous pressure has been experimentally shown to cause azotemia and reduced glomerular filtration rate, renal blood flow, urinary output, and sodium excretion. It has also been shown to increase plasma renin and aldosterone, and protein excretion. Venous congestion can also contribute to anemia in three different ways: reduced renal erythropoietin production, hemodilution due to fluid retention, and an inflammatory response leading to reduced gastrointestinal iron uptake.

[0006] Mechanically, increased renal venous pressure can cause increased intracapsular pressure and subsequently increased interstitial peritubular pressure, which can affect tubular function by increasing pressure in the Bowman's capsule (reducing sodium excretion) and also affect glomerular filtration.

[0007] In patients with heart failure, elevated renal venous pressure can result not only from elevated central venous (right atrial) pressure, but also from intraperitoneal fluid retention (ascites) exerting direct pressure on the renal veins. Reducing intraperitoneal pressure by fluid removal (e.g., using paracentesis and / or ultrafiltration) has been shown to reduce plasma creatinine levels in patients with heart failure.

[0008] Increased venous return caused by activation of the "leg muscle pump" during physical activity such as walking can increase systemic venous pressure, particularly in patients with heart failure, resulting in backflow into the renal veins. Summary of the Invention [Problem to be solved by the invention]

[0009] Typically, in patients with acute heart failure, elevated systemic venous pressure leads to elevated renal parenchymal pressure and elevated intraperitoneal pressure, factors that can contribute to impaired renal perfusion and function. Furthermore, high systemic venous pressure can impede lymphatic drainage of pulmonary interstitial fluid, resulting in worsening and prolonged pulmonary congestion in patients with acute pulmonary edema. [Means for solving the problem]

[0010] In accordance with some applications of the present invention, blood flow in a region of the vena cava adjacent a junction of the vena cava with the renal vein is separated from a subject's vena cava blood flow upstream and downstream of the junction. Blood is pumped from the region of the vena cava adjacent the junction to an adrenal location within the vena cava using a pump. The subject's blood is allowed to flow from an infrarenal location to an adrenal location within the subject's vena cava without being pumped by the pump, by directing the blood to bypass the pump.

[0011] In some applications, such a method includes: (a) at least partially occluding blood flow through a vein by placing a downstream occlusion element (e.g., a material) at a downstream location downstream of a junction between the vein and one or more tributary vessels (e.g., one or more tributary veins); (b) pumping blood with a pump from a region of the vein adjacent the junction between the vein and the tributary vessel through the downstream occlusion element; and (c) directing upstream venous blood flow from an upstream location upstream of the junction between the vein and the tributary vessel downstream of the occlusion element by directing the blood flow to bypass the pump without being pumped by the pump.

[0012] Typically, such methods are performed with a blood pump catheter including a material. The material is configured to be placed at a downstream location downstream of the junction of the vein and the tributary vessel and to at least partially occlude blood flow through the vein at the downstream location. The material typically defines a blood outlet opening. The blood pump is typically configured to pump blood from a region of the vein adjacent the junction of the vein and the tributary vessel through the blood outlet opening defined in the material. A blood flow pathway (i.e., blood flow channel) typically passes between an inlet opening located at an upstream location upstream of the junction of the vein and the tributary vessel and an outlet opening that opens on a downstream side of the material. The blood flow pathway is configured to direct upstream venous blood flow from the upstream location to downstream of the material without pumping by the pump. In some applications, the blood flow pathway includes a funnel and one or more tubes. The funnel is configured to be placed at an upstream location upstream of the junction of the vein and the tributary vessel and the one or more tubes are configured to extend from the funnel to a downstream side of the material. The funnel and the one or more tubes are configured to direct upstream venous blood flow from an upstream location to the material downstream without pumping the upstream venous blood flow through a pump.

[0013] In general, the scope of some applications of the present invention includes devices and methods for use with a subject's venous system that includes a tributary vein (e.g., a renal vein that drains into a vena cava) that drains into a main vein. Typically, such methods include isolating blood flow in a region of the main vein adjacent to a junction between the main vein and a tributary vein from blood flow in the main vein upstream and downstream thereof, pumping blood from a region of the main vein adjacent to a junction between the vein and the tributary vein to a location in the main vein downstream of the tributary vein using a pump, and directing the subject's blood to flow from a location in the main vein upstream of the tributary vein to a location in the main vein downstream of the tributary vein by directing the blood to bypass the pump without pumping with the pump. The scope of some applications of the present invention further includes devices and methods for use with a subject's venous system that includes a tributary vessel (e.g., a lymphatic vessel) that drains into a vein. Typically, such methods include isolating flow in a region of a vein adjacent a junction between the vein and a tributary vessel from blood flow in the vein upstream and downstream of the junction, pumping blood with a pump from a region of the vein adjacent the junction between the vein and a tributary vessel to a location in the vein downstream of the region, and directing a subject's blood to flow from a location in the vein upstream of the tributary vessel to a location in the vein downstream of the tributary vessel without pumping with the pump by directing the blood to bypass the pump.

[0014] In some applications of the invention, the blood pump catheter includes an impeller configured to pump blood by rotation and an impeller housing configured to be disposed around the impeller. The blood pump support frame is typically configured to be disposed upstream of the impeller housing and to at least partially align a longitudinal axis of the impeller housing with a local longitudinal axis of the blood vessel by contacting an inner wall of the blood vessel. A material is configured to extend from the impeller housing to the blood pump support frame to contact the vessel wall and occlude the blood vessel in a region of the blood vessel surrounding the impeller. In some applications, the material defines a blood outlet opening, and the impeller is configured to pump blood through the blood outlet opening.

[0015] In some applications, a blood pump catheter is configured for use with the descending aorta of a subject. The blood pump catheter includes a material configured to be placed within the descending aorta and to separate the aorta into an upstream compartment and a downstream compartment by at least partially occluding blood flow through the aorta. The material typically defines a blood outlet opening. A blood pump (e.g., an impeller-based blood pump) is configured to pump blood flowing through the descending aorta in a downstream direction through the blood outlet opening.

[0016] In general, in this specification and the claims of this application, the term "proximal" and related terms, when used in connection with a device or portion of a device, should typically be interpreted to mean the end of the device or portion that is closer to the insertion location when the device or portion is inserted into the body of a subject. The term "distal" and related terms, when used in connection with a device or portion of a device, should typically be interpreted to mean the end of the device or portion that is farther from the insertion location when the device or portion is inserted into the body of a subject.

[0017] The terms "downstream" and "upstream," and related terms, should be construed as defined relative to the direction of antegrade blood flow through a subject's vasculature. Thus, by way of example, the suprarenal vena cava is downstream of the infrarenal vena cava, and the descending aorta is downstream of the aortic arch. When used in connection with a device, the term "upstream" should be construed as indicating a portion of the device that is configured to be positioned at a relatively upstream location, and the term "downstream" should be construed as indicating a portion of the device that is configured to be positioned at a relatively downstream location.

[0018] Thus, in accordance with some applications of the present invention, there is provided an apparatus for use with a subject's venous system that includes one or more tributary vessels that drain into a vein at a junction of the vein and the one or more tributary vessels. 1. A blood pump catheter comprising: a material defining a blood exit opening configured to be placed at a downstream location downstream of the junction and to at least partially occlude blood flow through the vein at the downstream location; a blood pump configured to pump blood from a region of the vein adjacent the junction through a blood outlet opening defined in the material; a blood pump catheter including: (a) a blood flow pathway passing between a pathway inlet opening disposed at an upstream location upstream of the junction; and (b) a pathway outlet opening opening on a downstream side of the material; The blood flow pathway is configured to direct upstream venous blood flow from an upstream location downstream of the material without pumping the blood through a pump.

[0019] In some applications, the blood pump includes an elongated blood pump tube defining a blood inlet area disposed within an upstream portion of the elongated blood pump tube, a blood outlet area disposed within a downstream portion of the elongated blood pump tube, and an impeller configured to pump blood into the blood inlet area and further out of the blood outlet area through the elongated blood pump tube.

[0020] For some applications, the blood pump includes an impeller disposed within a frame, the impeller configured to pump blood by rotating within the frame.

[0021] In some applications, the blood pump catheter is configured for use with one or more lymphatic vessels draining into a vein, the blood pump catheter being configured to be placed in the vein, such that: a material is placed at a downstream location downstream of a junction between the vein and one or more lymphatic vessels and adapted to at least partially occlude blood flow through the vein at the downstream location; a blood pump configured to pump blood from a region of the vein adjacent a junction of the vein with one or more lymphatic vessels through a blood outlet opening defined in the material; a blood flow pathway passing between (a) a pathway inlet opening disposed at an upstream location upstream of a region of the vein adjacent a junction of the vein with one or more lymphatic vessels, and (b) a pathway outlet opening opening on a downstream side of the material; The blood flow pathway is configured to direct upstream venous blood flow from an upstream location to a downstream side of the material without pumping the blood through a pump.

[0022] For some applications, the blood pump catheter is configured to be placed in a vena cava of a subject, a material is placed at a downstream location downstream of a junction of the vena cava with one or more renal veins of a subject and adapted to at least partially occlude blood flow through the vena cava at the downstream location; a blood pump configured to pump blood from a region of the vena cava adjacent a junction of the vena cava with the one or more renal veins through a blood outlet opening defined in the material; a blood flow pathway passing between (a) a pathway inlet opening disposed at an upstream location upstream of a junction of the vena cava and one or more renal veins, and (b) a pathway outlet opening opening on a downstream side of the material; The blood flow pathway is configured to direct blood flow from the inferior renal vena cava blood flow downstream of the material without pumping the inferior renal vena cava blood flow.

[0023] For some applications, the apparatus further includes a percutaneous left ventricular assist device configured to assist function of the subject's left ventricle.

[0024] In some applications, the blood pump includes an elongated blood pump tube defining a blood inlet area disposed within an upstream portion of the elongated blood pump tube, a blood outlet area disposed within a downstream portion of the elongated blood pump tube, and an impeller configured to pump blood into the blood inlet area and further out of the blood outlet area through the elongated blood pump tube.

[0025] In some applications, the elongated blood pump tube is configured to be positioned such that the blood outlet area is positioned within a pulmonary artery of the subject and configured to pump blood through the elongated tube and into the pulmonary artery of the subject.

[0026] In some applications, the device further includes an elongated tube extending downstream from the material and defining an adrenal blood inlet opening configured to be positioned within the adrenal vena cava of the subject, a blood inlet area of ​​the elongated blood pump tube configured to be positioned downstream of the adrenal blood inlet opening, and the elongated blood pump tube configured to pump blood from the adrenal vena cava blood flow into the pulmonary artery of the subject.

[0027] For some applications, the apparatus further includes an elongated tube configured to extend into a pulmonary artery of the subject, and the blood pump configured to pump blood through the elongated tube and into the pulmonary artery of the subject.

[0028] In some applications, the elongated tube defines an adrenal blood inlet opening configured to be positioned within the adrenal vena cava of the subject, and the blood pump is configured to be positioned downstream of the adrenal blood inlet opening and configured to pump blood from the adrenal vena cava blood flow into the pulmonary artery of the subject.

[0029] In some applications, the diameter of one or more portions of the blood flow pathway is adjustable such that flow from the inferior renal vena cava blood flow to the subject's right atrium is adjustable.

[0030] In some applications, the device further includes a blood pressure sensor configured to detect a blood pressure of the subject, and a computer processor configured to receive the blood pressure of the subject and automatically adjust a diameter of one or more portions of the blood flow pathway in response to the detected blood pressure.

[0031] For some applications, a diameter of one or more portions of the blood flow pathway is configured to adjust in response to an input force.

[0032] In some applications, the blood flow pathway includes a funnel having a wide end and a narrow end and one or more tubes, where the wide end of the funnel defines the pathway entrance opening and the narrow end of the funnel extends into the one or more tubes.

[0033] In some applications, the funnel and the one or more tubes comprise a single continuous blood flow pathway.

[0034] For some applications, the diameter of one or more portions of the blood flow pathway is adjustable such that flow through the blood flow pathway is adjustable.

[0035] In some applications, the device further includes a blood pressure sensor configured to detect a blood pressure of the subject, and a computer processor configured to receive the blood pressure of the subject and automatically adjust a diameter of one or more portions of the blood flow pathway in response to the detected blood pressure.

[0036] For some applications, a diameter of one or more portions of the blood flow pathway is configured to adjust in response to an input force.

[0037] Further, in accordance with some aspects of the present invention, there is provided an apparatus comprising: 1. A blood pump catheter comprising: a material defining a blood exit aperture disposed on the blood pump catheter and configured to at least partially occlude blood flow through the vein; a blood pump configured to pump blood through a blood outlet opening defined in the material; a blood pump catheter including: (a) a blood flow pathway passing between a pathway inlet opening disposed at a position proximal to the material; and (b) a pathway outlet opening opening at a position distal to the material; The blood flow pathway is configured to direct blood flow from the pathway inlet opening to the pathway outlet opening without pumping by a pump.

[0038] Further, in accordance with some applications of the present invention, there is provided a method for use with a subject's venous system that includes a tributary vessel that drains into a vein at a junction between the vein and the tributary vessel, the method comprising: separating blood flow in a region of the vein adjacent the junction into a compartment separate from blood flow in the vein upstream of the junction and blood flow in the vein downstream of the junction; pumping blood from the compartment to a compartment downstream with a pump; directing blood of the subject to flow from a location in the vein upstream of the compartment to a location downstream of the compartment by bypassing the pump without pumping the blood through the pump; Includes.

[0039] In some applications, pumping blood from the compartment downstream of the compartment includes pumping blood from the compartment downstream of the compartment through an elongated blood pump tube defining a blood inlet area disposed within an upstream portion of the elongated blood pump tube, a blood outlet area disposed within a downstream portion of the elongated blood pump tube, and an impeller configured to pump blood into the blood inlet area and further out of the blood outlet area through the elongated blood pump tube.

[0040] In some applications, pumping blood from the compartment downstream of the compartment includes pumping blood from the compartment downstream of the compartment by rotating an impeller.

[0041] In some applications, the method is for use with one or more lymphatic vessels draining into a vein. separating blood flow within a region of the vein adjacent a junction of the vein with one or more lymphatic vessels into a compartment separate from blood flow within the vein downstream of the region of the vein adjacent a junction of the vein with one or more lymphatic vessels and blood flow within the vein upstream of the region of the vein adjacent a junction of the vein with one or more lymphatic vessels; pumping blood from the compartment to a compartment downstream with a pump; directing blood of the subject to flow from a location in the vein upstream of the compartment to a location downstream of the compartment by bypassing the pump without pumping the blood through the pump; Includes.

[0042] In some applications, the method is for use with the renal vein and vena cava of a subject. separating blood flow within a region of the vena cava adjacent a junction of the vena cava with one or more renal veins into a vena cava segment that is separate from blood flow within the vena cava downstream of the vena cava segment and blood flow within the vena cava upstream of the vena cava segment; pumping blood from the vena cava compartment to a downstream vena cava compartment with a pump; directing blood of the subject to flow from a location upstream of the vena cava compartment to a location downstream of the vena cava compartment without pumping the blood through the pump and bypassing the pump; Includes.

[0043] For some applications, the method further includes supporting left ventricular function in the subject with a percutaneous left ventricular assist device.

[0044] In some applications, pumping blood from the vena cava segment to the downstream vena cava segment includes pumping blood from the vena cava segment to the downstream vena cava segment through an elongated blood pump tube defining a blood inlet area disposed within an upstream portion of the elongated blood pump tube, a blood outlet area disposed within a downstream portion of the elongated blood pump tube, and an impeller configured to pump blood into the blood inlet area and further out of the blood outlet area through the elongated blood pump tube.

[0045] In some applications, pumping blood from the vena cava compartment downstream of the vena cava compartment through the elongated blood pump tube includes pumping blood through the elongated tube into a pulmonary artery of the subject.

[0046] For some applications, the method further includes pumping blood from the subject's adrenal vena cava blood flow via an elongated blood pump tube and into the subject's pulmonary artery.

[0047] In some applications, pumping blood from the vena cava compartment downstream of the vena cava compartment includes pumping blood through an elongated tube and into a pulmonary artery of the subject.

[0048] For some applications, the method further includes pumping blood from the subject's adrenal vena cava blood flow via the elongated tube and into the subject's pulmonary artery.

[0049] In some applications, directing blood to bypass the pump includes directing blood to bypass the pump via a blood flow pathway, and the method further includes adjusting blood flow to the right atrium of the subject by adjusting a diameter of one or more portions of the blood flow pathway.

[0050] In some applications, the method further includes detecting a blood pressure of the subject, and adjusting a diameter of the one or more portions of the blood flow pathway includes automatically adjusting a diameter of the one or more portions of the blood flow pathway in response to the detected blood pressure.

[0051] For some applications, adjusting a diameter of one or more portions of the blood flow pathway includes adjusting a diameter of one or more portions of the blood flow pathway in response to an input.

[0052] In some applications, directing blood to bypass the pump includes directing blood to bypass the pump through a blood flow pathway, and the method further includes adjusting blood flow through the blood flow pathway by adjusting a diameter of one or more portions of the blood flow pathway.

[0053] In some applications, the method further includes detecting a blood pressure of the subject, and adjusting a diameter of the one or more portions of the blood flow pathway includes automatically adjusting a diameter of the one or more portions of the blood flow pathway in response to the detected blood pressure.

[0054] For some applications, adjusting a diameter of one or more portions of the blood flow pathway includes adjusting a diameter of one or more portions of the blood flow pathway in response to an input.

[0055] Further, in accordance with some applications of the present invention, a method is provided for use with a subject's venous system that includes a tributary vessel that drains into a vein at a junction between the tributary vessel and the vein, the method comprising: at least partially occluding blood flow through the vein by placing a downstream occlusion element at a downstream location downstream of the junction of the vein and a tributary vessel; pumping blood from a region of the vein adjacent a junction of the vein and a tributary vessel through a downstream occlusion element with a pump; directing upstream venous blood flow from an upstream location upstream of the junction of the vein and a tributary vessel to a location downstream of the occlusion element by directing the upstream venous blood flow to bypass the pump without being pumped by the pump; Includes.

[0056] Further, in accordance with some applications of the present invention, a method is provided for use with a subject's venous system that includes a tributary vessel that drains into a vein at a junction between the tributary vessel and the vein, the method comprising: separating blood flow in a region of the vein adjacent the junction from blood flow in the vein upstream of the region of the vein adjacent the junction and blood flow in the vein downstream of the region of the vein adjacent the junction; flowing blood from the tributary vessel through a first flow path to a location downstream of the tributary vessel; flowing blood of the subject via a second flow path from a location within the vein upstream of the tributary vessel to a location within the vein downstream of the tributary vessel; controlling blood flow through at least one of the first and second flow paths; Includes.

[0057] Further, in accordance with some applications of the present invention, there is provided an apparatus for use with a subject's arterial system that includes a main artery and one or more branch arteries branching from the main artery at a junction of the main artery with the one or more branch arteries, the apparatus comprising: 1. A blood pump catheter comprising: a material defining a blood inlet opening configured to be placed at a downstream location downstream of a junction of a main artery and a branch artery and to at least partially occlude blood flow through the main artery at the downstream location; a blood pump configured to pump blood from a main artery towards a branch artery through a blood inlet opening; a funnel configured to be placed in an upstream position upstream of a junction of a main artery and a branch artery; a blood pump catheter including: (a) a blood flow pathway passing between a pathway inlet opening disposed at an upstream location upstream of a junction of a main artery and a branch artery; and (b) a pathway outlet opening opening to a downstream side of the material; The blood flow pathway is configured to direct upstream major arterial blood flow from an upstream location downstream of the material without pumping the blood flow through a pump.

[0058] Further, in accordance with some applications of the present invention, there is provided a method for use with a subject's arterial system that includes a main artery and one or more branch arteries branching from the main artery at a junction of the main artery with the one or more branch arteries, the method comprising: separating blood flow in a region of the main artery adjacent the junction into a compartment separate from blood flow in the main artery and blood flow in the compartment downstream of the compartment; pumping blood from a main artery to a branch artery with a pump; directing blood of the subject to flow from a location in a major artery upstream of the compartment to a location downstream of the compartment by bypassing the pump without pumping the blood through the pump; Includes.

[0059] Further, in accordance with some applications of the present invention, there is provided a method for use with a subject's arterial system that includes a main artery and one or more branch arteries branching from the main artery at a junction of the main artery with the one or more branch arteries, the method comprising: at least partially occluding blood flow through the main artery by placing a downstream occlusion element at a downstream location downstream of the junction of the main artery and the branch artery; pumping blood from the main artery to the branch artery through the downstream occlusion element with a pump; directing upstream main artery blood flow from an upstream location upstream of a junction of the main artery and a branch artery to a location downstream of the occlusion element by directing the upstream main artery blood flow around the pump without pumping the blood through the pump; Includes.

[0060] Also, in accordance with some applications of the present invention, there is provided an apparatus for use with the descending aorta of a subject, the apparatus comprising: 1. A blood pump catheter comprising: a material defining a blood exit aperture configured to be placed within the descending aorta and to separate the aorta into an upstream section and a downstream section by at least partially occluding blood flow through the aorta; a blood pump configured to pump blood flowing through the descending aorta in a downstream direction through a blood outlet opening; 16. An apparatus comprising: a blood pump catheter comprising:

[0061] Also provided in accordance with some applications of the present invention is a method for use with the descending aorta of a subject, the method comprising: separating the descending aorta into an upstream section and a downstream section by placing an occlusion element within the descending aorta that at least partially occludes the descending aorta; pumping blood from the upstream compartment to the downstream compartment with a pump; Includes.

[0062] Further, in accordance with some aspects of the present invention, there is provided an apparatus comprising: 1. A blood pump catheter configured to be placed in a blood vessel of a subject, comprising: an impeller configured to pump blood by rotation; an impeller housing configured to be disposed around the impeller; a blood pump support frame configured to be positioned upstream of the impeller housing and to at least partially align a longitudinal axis of the impeller housing with a local longitudinal axis of the blood vessel by contacting an inner wall of the blood vessel; The blood pump catheter includes a material extending from the impeller housing to the blood pump support frame and defining a blood outlet opening configured to contact the blood vessel wall and occlude the blood vessel in a region of the blood vessel surrounding the impeller, the impeller being configured to pump blood through the blood outlet opening.

[0063] The present invention will be more fully understood from the following detailed description of the embodiments thereof, when read in conjunction with the drawings. [Brief description of the drawings]

[0064] [Figure 1A] 1 is a schematic diagram of a blood pump catheter placed in a subject's vena cava, in accordance with some applications of the present invention. [Figure 1B] 1 is a schematic diagram of a blood pump catheter placed in a subject's vena cava, in accordance with some applications of the present invention. [Figure 1C] 1 is a schematic diagram of a blood pump catheter placed in a subject's vena cava, in accordance with some applications of the present invention. [Figure 2A] 1 is a schematic diagram of a blood pump catheter placed in a subject's vena cava, in accordance with some applications of the present invention. [Figure 2B] 1 is a schematic diagram of a blood pump catheter placed in a subject's vena cava, in accordance with some applications of the present invention. [Figure 2C] 1 is a schematic diagram of a blood pump catheter placed in a subject's vena cava, in accordance with some applications of the present invention. [Figure 2D]1 is a schematic diagram of a blood pump catheter positioned in a subject's vena cava, the blood pump having a non-axisymmetric outflow tube, in accordance with some applications of the present invention. [Figure 2E] 1 is a schematic diagram of a blood pump catheter positioned within a subject's vena cava, the blood pump having a non-axisymmetric outflow tube and a non-axisymmetric impeller, in accordance with some applications of the present invention. [Figure 2F] FIG. 2F is a schematic diagram of the blood pump catheter of FIG. 2E without the target anatomy, in accordance with some applications of the present invention. [Figure 3A] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3B] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3C] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3D] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3E] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3F] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3G] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 3H] 1 is a schematic diagram of a blood pump catheter according to some alternative applications of the present invention. [Figure 4A] 1 is a schematic diagram of a blood pump catheter placed in a subject's descending aorta near the subject's renal arteries, in accordance with some applications of the present invention. [Figure 4B] 1 is a schematic diagram of a blood pump catheter placed in a subject's descending aorta near the subject's renal arteries, in accordance with some applications of the present invention. [Figure 5A]1 is a schematic diagram of a blood pump catheter positioned within a subject's descending aorta (e.g., the thoracic aorta or abdominal aorta), in accordance with some applications of the present invention. [Figure 5B] 1 is a schematic diagram of a blood pump catheter positioned within a subject's descending aorta (e.g., the thoracic aorta or abdominal aorta), in accordance with some applications of the present invention. [Figure 6A] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6B] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6C] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6D] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6E] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6F] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6G] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 6H] 1 is a schematic diagram of a blood pump impeller or a portion thereof, in accordance with some applications of the present invention. [Figure 7] 1 is a schematic diagram of an impeller disposed within a frame of a blood pump, in accordance with some applications of the present invention. [Figure 8A] 1 is a schematic diagram of a blood pump impeller and frame in a radially unconstrained state, in accordance with some applications of the present invention. [Figure 8B] 1 is a schematic diagram of a blood pump impeller and frame in a radially constrained state, in accordance with some applications of the present invention. [Figure 8C]FIG. 1 is a schematic diagram of a typical bearing assembly used in prior art axial impeller-based blood pumps. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] 1A-1C, which are schematic diagrams of a blood pump catheter 20 placed in a subject's vena cava 22, according to some applications of the present invention. Typically, the blood pump catheter includes a blood pump 24, including an impeller housing 26 and an impeller 50 disposed within the impeller housing. The impeller housing 26 (e.g., a housing frame 34) typically functions to separate the inner wall of the vena cava from the impeller (e.g., in case the vena cava collapses internally due to intraperitoneal pressure) so that the vena cava is not damaged by the impeller and the impeller is not deformed by pressure from the inner wall of the vena cava. Also, typically, an axial shaft 92 (shown in FIG. 7) that passes through the impeller is supported by radial bearings 116, 118 disposed at the proximal and distal ends of the impeller housing, respectively.

[0066] For purposes of illustration, it should be noted that Figures 1A-1C (as well as Figures 2A-2E, 3A-3H, 4A-4B, and 5A-5B) show a three-dimensional view of blood pump 24, but show cross-sectional views of other elements of the blood pump catheter.

[0067] In some such applications, the blood pump support frame 32 is disposed upstream of the impeller housing 26 and configured to contact the inner wall of the vena cava. The blood pump support frame 32 is configured to contact the inner wall of the vena cava to align the longitudinal axis of the impeller housing 26, and thereby the impeller 50, with the local longitudinal axis of the vena cava. (It should be noted that in some applications, the blood pump support frame may not perfectly align the longitudinal axis of the impeller with the local longitudinal axis of the vena cava. Typically, however, the blood pump support frame maintains the longitudinal axis of the impeller in better alignment with the local longitudinal axis of the vena cava than the longitudinal axis of the impeller would be in the absence of the blood pump support frame.) Typically, other things being equal, the greater the effectiveness of pumping blood by the impeller 50, the better the alignment of the longitudinal axis of the impeller with the local longitudinal axis of the vena cava. Nevertheless, it should be noted that even slight misalignment of the impeller's longitudinal axis with the local longitudinal axis of the vena cava (as shown, for example, in Figure 2E) usually results in effective pumping of blood by the impeller.

[0068] In some applications, the impeller housing 26 includes a frame 34 (e.g., a rigid or semi-rigid frame) made of a shape memory element (such as Nitinol) that is at least partially coated with a material 36 (e.g., a blood impermeable material such as polyester, polyurethane, and / or a different polymer). Typically, in such applications, the frame 34 is sufficiently rigid that it does not deform due to pressure exerted by the inner wall of the vena cava on the frame 34. Typically, the material 36 extends from the impeller housing to the blood pump support frame 32 to contact the vessel wall and occlude the vessel in a region of the vessel surrounding and / or upstream of the impeller. The material typically defines a through hole in a distal portion of the impeller housing. The material is configured to occlude blood backflow around the outside of the impeller, but allow antegrade blood flow in a central region of the vessel near the impeller, with the hole acting as the blood outlet opening 31. In some applications, a portion of the impeller housing is covered (i.e., lined) on the inside of the impeller housing with an inner lining 39, for example, as described below with reference to Figure 7. In some such applications, the inner lining of the impeller housing at least partially overlaps material 36. In some applications, the inner lining extends the blood exit opening defined in material 36.

[0069] Typically, a drive cable 78 is disposed within an outer tube 77 of the blood pump catheter 20 (the drive cable is shown, for example, in FIG. 8A). More typically, the drive cable extends from a motor 79 disposed outside the subject's body to an axial shaft 92 (shown in FIG. 7) on which the impeller is disposed. The motor provides rotational motion to the axial shaft (and thereby to the impeller) via the drive cable. Typically, the motor is controlled by the computer processor 10. In some applications, the motor is controlled based on blood pressure measurements performed by a pressure sensor 75.

[0070] In some applications, the use of material 36 as described above reduces the likelihood of blood backflow due to turbulence caused by the impeller in the vascular region surrounding the impeller. In some applications, the material acts to separate the suprarenal vena cava into upstream and downstream compartments, and the impeller is configured to pump blood from the upstream compartment to the downstream compartment, thereby reducing pressure in the upstream compartment adjacent the renal vein.

[0071] In some applications (not shown), the blood pump support frame 32 and the frame 34 of the impeller housing 26 are formed as a single frame having an upstream portion configured to contact the inner wall of the vena cava and a downstream portion configured to house the impeller.

[0072] Typically, the maximum diameter of the blood pump support frame 32 when the blood pump support frame is in a radially unconstrained configuration (i.e., the diameter of the blood pump support frame 32 at one or more longitudinal positions where the diameter of the blood pump support frame 32 is maximum) is at least 1.1 times (and in some applications at least 1.3 times) the maximum diameter of the frame 34 of the impeller housing 26 when the frame 34 is in a radially unconstrained configuration (i.e., the diameter of the frame 34 at one or more longitudinal positions where the diameter of the frame 34 is maximum).

[0073] Typically, the blood pump 24 is positioned downstream of the junction of the vena cava with the subject's renal vein 25 and configured to pump blood in a downstream direction to reduce pressure in the subject's renal vein. In some applications, the blood pump catheter 20 includes an occlusion element 40 configured to be positioned upstream of the junction of the vena cava with the subject's renal vein and to partially occlude the vena cava at this location. For example, the occlusion element may include a balloon 42 as shown in FIG. 1A. Alternatively or additionally, the occlusion element includes a blood-impermeable material 44 defining a through hole 45 as shown in FIG. 1B. In some applications, the material is supported by a frame 46. Typically, the material 44 is configured such that there is some blood flow through the pores of the material, but the blood flow is reduced compared to when the material is not present. Typically, the occlusion element is configured to partially occlude the vena cava upstream of the junction of the vena cava with the subject's renal vein. In some applications (not shown), a nozzle is used as the upstream occlusion element. This is described, for example, in U.S. Patent Application Publication No. 2019 / 0239998 to Tuval, which is incorporated herein by reference.

[0074] The occlusion element 40 is configured to partially occlude the subject's vena cava such that blood flow from the subject's lower body toward the subject's heart in response to pumping of the downstream blood pump is not significantly increased, and such that a low pressure region is created in the vena cava between the occlusion element and the downstream blood pump, the pressure being lower than the subject's central venous pressure. Typically, creating the low pressure region increases blood flow from the renal vein to the vena cava, thereby lowering renal blood pressure and increasing renal perfusion. It should be noted that the occlusion element is configured to partially but not totally occlude the vena cava, creating a low pressure region in the vena cava but allowing substantial blood flow through the vena cava.

[0075] In some applications, the blood pump catheter 20 does not include an upstream occlusion element, as shown in FIG. 1C for example. As described above, in some applications, the material 36 acts to separate the suprarenal vena cava into an upstream section and a downstream section, and the impeller 50 is configured to pump blood from the upstream section to the downstream section, thereby reducing pressure in the upstream section adjacent the renal vein. In some applications, the blood pump catheter 20 is configured to thereby generate a low pressure region in the vena cava adjacent the renal vein, even in the absence of an upstream occlusion element, as shown in FIG. 1C. Typically, generating a low pressure region increases blood flow from the renal vein to the vena cava, thereby reducing renal blood pressure and increasing renal perfusion.

[0076] The blood pump catheter 20 is typically placed in and operated within the subject's vena cava 22 to provide acute treatment to a subject suffering from cardiac dysfunction, congestive heart failure, low renal blood flow, high renal vascular resistance, arterial hypertension, diabetes, and / or renal dysfunction. For example, the blood pump catheter may be placed in and operated within the subject's vena cava for a period of more than one hour (e.g., more than one day), less than one week (e.g., less than four days), and / or between one hour and one week (e.g., between one and four days). In some applications, the blood pump catheter is placed chronically within the subject's vena cava to provide long-term treatment to a subject suffering from cardiac dysfunction, congestive heart failure, low renal blood flow, high renal vascular resistance, arterial hypertension, diabetes, and / or renal dysfunction. In some applications, a course of treatment is applied to the subject over a period of weeks, months, or years, during which the blood pump catheter is intermittently placed within the subject's vena cava and the subject is intermittently treated according to the techniques described herein. For example, a subject can be treated intermittently, at intervals of days, weeks, or months.

[0077] With respect to the catheters shown in Figures 1A-1B, it should be noted that such catheters, including a blood pump 24 disposed distally to an upstream occlusion element, are suitable for placement into a vein cava from a vein below the junction of the vein cava with the subject's renal veins, such as the femoral vein. However, the scope of the present invention includes catheters in which a pump and an occlusion element are disposed, but the upstream occlusion element is disposed distally to the downstream pump. Such catheters are typically inserted, mutatis mutandis, via a vein above the inferior vena cava, such as the subclavian or jugular vein. Similarly, the catheter shown diagrammatically in Figure 1C may be configured, mutatis mutandis, for insertion into the adrenal vena cava via a vein above the inferior vena cava, such as the subclavian or jugular vein. Typically, in such cases, the orientation of the blood pump catheter components relative to the catheter shaft is in the opposite direction to that shown in Figures 1A-1C.

[0078] Typically, the blood pump catheter is inserted under fluoroscopic imaging, or alternatively, the blood pump catheter is inserted under ultrasound imaging to reduce the subject's exposure to radiation and / or contrast agents.

[0079] As mentioned above, the blood pump catheter 20 is typically placed in the vena cava of a subject suffering from cardiac dysfunction, congestive heart failure, low renal blood flow, high renal vascular resistance, arterial hypertension, diabetes, and / or renal dysfunction. Typically, operating the blood pump catheter in the vena cava of such a subject causes a reduction and flattening of the subject's renal vein pressure profile, even as the subject's central venous pressure increases and has the added effect of increasing the subject's central venous pressure. This is described, for example, with reference to FIG. 4B of U.S. Patent Application Publication No. 2016 / 0022890 to Schwammenthal, which is incorporated herein by reference.

[0080] As described above, typically the occlusion element is configured to partially occlude the vena cava upstream of the junction of the vena cava with the subject's renal vein. In some applications, the diameter to which the occlusion element expands is controllable. For example, the inflation of the balloon can be controllable or the frame can be expandable (e.g., by heating the frame or applying an electric current to the frame). In some applications, the extent to which the occlusion element occludes the vena cava is controlled by the computer processor 10 in response to input from different sensors (e.g., a flow sensor and / or an oxygen saturation sensor and / or a heat flow sensor, such as described with reference to Figures 22Ai-Cii of U.S. Patent Application Publication No. 2016 / 0022890 to Schwammenthal, which is incorporated herein by reference) and / or in response to input from a user, depending on the blood pressure detected by the blood pressure sensor 75. In some applications, the rate at which pump 24 pumps blood from the renal vein (e.g., the speed at which pump impeller 50 rotates) and / or the extent to which the occlusion element occludes the vena cava is controlled by computer processor 10 in response to blood pressure detected by blood pressure sensor 75 in response to input from different sensors (e.g., flow rate sensors and / or oxygen saturation sensors and / or heat flow sensors, as described with reference to Figures 22Ai-Cii of U.S. Patent Application Publication No. 2016 / 0022890 to Schwammenthal, which is incorporated herein by reference) and / or in response to input from a user. In some applications, blood pressure sensors, such as those described below with reference to Figures 1C and 2C, are used in conjunction with the above-described devices and methods.

[0081] Although some applications of the invention are described with reference to a blood pump, which accordingly includes an impeller, the scope of the invention includes, mutatis mutandis, the use of any other type of pump for pumping blood as described herein For example, roller pumps, Archimedes screw pumps, centrifugal pumps, pneumatic pumps, and / or compression pumps may be used.

[0082] With respect to Figures 1A-1C, it should be noted that the scope of the present invention includes the application of similar devices and methods to any venous system of a subject, including tributary veins draining into major veins. For example, similar techniques may be applied at the junction of the hepatic vein and the vena cava. In some applications, generally similar devices and methods are used in the subclavian or jugular vein at the junction of a vein with one or more lymphatic vessels. In some such applications, the blood pump catheter 20 is configured, mutatis mutandis, to increase lymphatic flow from the lymphatic vessels into a vein.

[0083] Reference is now made to Figures 2A and 2B, which are schematic diagrams of a blood pump catheter 70 placed in a subject's vena cava 22, according to some applications of the present invention. Typically, the blood pump catheter 70 includes a blood pump 24, which typically includes an impeller housing 26 and an impeller 50, all generally similar to those described above. The impeller housing 26 (e.g., the housing frame 34) typically functions to separate the inner wall of the vena cava from the impeller (e.g., in case the vena cava collapses internally due to intra-abdominal pressure) so that the vena cava is not damaged by the impeller and the impeller is not deformed by pressure from the inner wall of the vena cava. Also, an axial shaft 92 (shown in Figure 7) that passes through the impeller is typically supported by radial bearings 116, 118 located at the proximal and distal ends of the impeller housing, respectively.

[0084] In some such applications, the blood pump support frame 32 is disposed upstream of the impeller housing 26 and configured to contact the inner wall of the vena cava. The blood pump support frame 32 is configured to contact the inner wall of the vena cava to align the longitudinal axis of the impeller housing 26, and thereby the impeller 50, with the local longitudinal axis of the vena cava. (It should be noted that in some applications, the blood pump support frame may not perfectly align the longitudinal axis of the impeller with the local longitudinal axis of the vena cava. Typically, however, the blood pump support frame maintains the longitudinal axis of the impeller in better alignment with the local longitudinal axis of the vena cava than the longitudinal axis of the impeller would be in the absence of the blood pump support frame.) Typically, other things being equal, the greater the effectiveness of pumping blood by the impeller 50, the better the alignment of the longitudinal axis of the impeller with the local longitudinal axis of the vena cava. As mentioned above, it should nevertheless be noted that even slight misalignment of the impeller's longitudinal axis with the local longitudinal axis of the vena cava (as shown, for example, in FIG. 2E) typically results in effective pumping of blood by the impeller.

[0085] In some applications, the impeller housing 26 includes a frame 34 (e.g., a rigid or semi-rigid frame) made of a shape memory element (such as Nitinol) that is at least partially coated with a material 36 (e.g., a blood impermeable material such as polyester, polyurethane, and / or a different polymer). Typically, in such applications, the frame 34 is sufficiently rigid that it does not deform due to pressure exerted by the inner wall of the vena cava on the frame 34. Typically, the material 36 extends from the impeller housing to the blood pump support frame 32 to contact the vessel wall and occlude the vessel in a region of the vessel surrounding and / or upstream of the impeller. The material typically defines a through hole in a distal portion of the impeller housing. The material is configured to occlude blood backflow around the outside of the impeller, but allow antegrade blood flow in a central region of the vessel near the impeller, with the hole acting as the blood outlet opening 31. In some applications, a portion of the impeller housing is covered (i.e., lined) on the inside of the impeller housing with an inner lining 39, for example, as described below with reference to Figure 7. In some such applications, the inner lining of the impeller housing at least partially overlaps material 36. In some applications, the inner lining extends the blood exit opening defined in material 36.

[0086] Typically, a drive cable 78 is disposed within an outer tube 77 of the blood pump catheter 70 (the drive cable is shown, for example, in FIG. 8A ). Typically, the drive cable extends from a motor 79 disposed outside the subject's body to an axial shaft 92 (shown in FIG. 7 ) on which the impeller is disposed. The motor provides rotational motion to the axial shaft (and thereby to the impeller) via the drive cable. Typically, the motor is controlled by a computer processor 10. In some applications, the motor is controlled based on blood pressure measurements performed by a pressure sensor 75.

[0087] In some applications, the blood pump catheter further includes a funnel 72 extending into the tube 74. The funnel is configured to be placed upstream of the junction of the vena cava with the subject's renal vein and configured to direct all blood flow from the infrarenal vena cava into the tube 74. The tube 74 then directs blood flow from the infrarenal location to the adrenal location such that this blood flows to the adrenal location bypassing the blood pump 24 (i.e., without being pumped by the blood pump 24). For example, a tube 76 may extend from the tube 74 to the adrenal location bypassing the blood pump. As shown by the blood flow arrows in FIG. 2A, this allows blood to flow from the infrarenal vena cava to the adrenal vena cava without being pumped by the blood pump 24. In contrast, as shown by the blood flow arrows in FIG. 2B, blood is pumped by the blood pump 24 from a region of the vena cava adjacent the junction of the vena cava with the renal vein to the adrenal vena cava.

[0088] Thus, by deploying blood pump catheter 70 within the vena cava, blood flow in the region of the vena cava adjacent the junction of the vena cava with the renal vein is separated into a compartment 82 separate from the infrarenal vena cava blood flow 84 and the adrenal vena cava blood flow 86. Blood flow from the infrarenal vena cava blood flow 84 to the adrenal vena cava blood flow 86 occurs passively (e.g., by flowing through funnel 72, tube 74, and tube 76). Blood is actively pumped from compartment 82 to the adrenal blood flow using a blood pump. In this manner, a low pressure region is created within the vena cava in compartment 82, where the blood pressure is lower than the central venous pressure of the subject. Creating a low pressure region typically increases blood flow from the renal vein to the vena cava, thereby lowering renal blood pressure and increasing renal perfusion.

[0089] It should be noted that the specific configurations of funnel 72, tube 74, and tube 76 are shown by way of example only, and the scope of the present application includes, mutatis mutandis, the use of any other configuration of blood flow pathway 60 (i.e., blood flow channel) for directing blood from the infrarenal vena cava to the adrenal vena cava without pumping with blood pump 24. Typically, funnel 72, tube 74, and tube 76 comprise portions of a single continuous blood flow pathway. The blood flow pathway typically passes between a pathway inlet opening 61 located at an upstream location upstream of the junction of the vena cava with the renal vein, and a pathway outlet opening 63 that opens onto the downstream side of material 36. Typically, as shown in FIG. 2A, funnel 72 defines a wide end 85 and a narrow end 87. The wide end of the funnel typically defines an inlet opening to the blood flow pathway, and the narrow end of the funnel extends into one or more tubes (e.g., tubes 74 and 76).

[0090] Typically, the blood flow from the IRC 84 to the adrenal cava blood flow 86 is not substantially changed compared to the blood flow from the IRC 84 to the adrenal cava blood flow 86 in the absence of the blood pump catheter. In some applications, the blood flow from the IRC 84 to the adrenal cava blood flow 86 is controlled by controlling the diameter of one or more portions of the blood flow pathway 60. For example, the diameter of one or more portions of the blood flow pathway (e.g., funnel 72, tube 74, and / or one or more tubes 76) may be adjusted (e.g., using an expandable / contractable component disposed internally or externally to one of these elements). In this manner, the preload on, for example, the right atrium may be controlled.

[0091] In some applications, blood flow from the renal inferior vena cava blood flow 84 to the adrenal superior vena cava blood flow 86 is controlled in response to (e.g., automatically in response to) one or more pressure measurements, such as, for example, pressure measurements performed as described herein. Alternatively or additionally, blood flow from the renal inferior vena cava blood flow 84 to the adrenal superior vena cava blood flow 86 may be periodically adjusted (e.g., as described above). For example, a medical professional (or another person) may periodically adjust blood flow from the renal inferior vena cava blood flow 84 to the adrenal superior vena cava blood flow 86 in response to a change in the subject's condition (e.g., as described above).

[0092] In some applications, the diameter of one or more portions of blood flow pathway 60 (e.g., funnel 72, tube 74, and tube 76) is not adjustable, and the diameter of at least a portion of the blood flow pathway is such that blood flow from the inferior renal vena cava blood flow 84 to the adrenal vena cava blood flow 86 is reduced (compared to blood flow levels in the absence of these components) to reduce preload on the right atrium.

[0093] Reference is now made to Fig. 2C, which is a schematic diagram of a blood pump catheter 70 including blood pressure measurement tubes 71, 73, according to some applications of the present invention. Reference is also made again to Fig. 1C, which shows blood pump catheter 20 including blood pressure measurement tube 73, according to some applications of the present invention.

[0094] In some applications, at least one blood pressure measurement tube 71 is configured to extend at least to the exterior surface of the funnel 72 and / or tube 74 such that an opening at the distal end of the blood pressure measurement tube is in direct fluid communication with the patient's blood flow (i.e., renal vein blood flow) outside the funnel 72 and / or tube 74. The pressure sensor 75 measures the blood pressure in the blood pressure measurement tube. Typically, by measuring the blood pressure in the blood pressure measurement tube, the blood pressure sensor measures the subject's blood pressure outside the funnel 72 and / or tube 74, which is indicative of the renal vein blood pressure. Typically, the blood pressure measurement tube 71 extends from outside the subject's body to an opening at the distal end of the tube, and the pressure sensor is located near the proximal end of the tube, e.g., outside the subject's body. In some applications, the computer processor 10 receives an indication of the measured blood pressure and controls pumping of the blood pressure by the impeller in response to the measured blood pressure.

[0095] In some applications of the blood pump catheter 20, blood pump catheter 70, or blood pump catheter 90 (described below), at least one blood pressure measuring tube 73 is configured to extend at least to the outer surface of the material 36 such that an opening at the distal end of the blood pressure measuring tube is in direct fluid communication with the blood flow of the subject outside the material 36 (e.g., adrenal vena cava pressure). The pressure sensor 75 measures the blood pressure in the blood pressure measuring tube. Typically, by measuring the blood pressure in the blood pressure measuring tube, the blood pressure sensor measures the blood pressure of the subject outside the material 36, which in the examples shown in Figures 1C and 2C represents the adrenal vena cava pressure. Typically, the blood pressure measuring tube 73 extends from outside the subject's body to an opening at the distal end of the tube, and the pressure sensor is located near the proximal end of the tube, e.g., outside the subject's body. In some applications, the computer processor 10 receives an indication of the measured blood pressure and controls the pumping of the blood pressure by the impeller in response to the measured blood pressure. In some applications (e.g., when used with blood pump catheter 70), the computer processor adjusts blood flow (e.g., as described above) from the infrarenal vena cava blood flow 84 to the adrenal vena cava blood flow 86 in response to the measured blood pressure. In some applications (e.g., when used with blood pump catheter 20 as shown in Figures 1A and 1B), the computer processor adjusts the diameter to which occlusion element 40 expands in response to the measured blood pressure.

[0096] As mentioned above, a drive cable 78 is typically disposed within the outer tube 77 of the blood pump catheters 20, 70, and 90. (The drive cable is shown, for example, in FIG. 7A.) ​​Typically, the drive cable extends from a motor 79 disposed outside the subject's body to an axial shaft 92 on which the impeller is disposed. The motor provides rotational motion to the axial shaft (and thereby to the impeller) via the drive cable. In some applications, one or more blood pressure measurement tubes 71, 73 are disposed within the outer tube 77, surrounding the drive cable along at least a portion of the length of the blood pressure measurement tube.

[0097] As shown in Figures 1C and 2C, in some applications of the blood pump catheter 20 or blood pump catheter 70, the IRCAV blood pressure is measured using at least one blood pressure measuring tube that defines an opening 83 in the outer tube 77 at its distal end. The blood pressure measuring tube is configured to extend from outside the subject's body to the outer surface of the outer tube 77 in the IRCAV of the subject, such that the opening at the distal end of the blood pressure measuring tube is in direct fluid communication with the IRCAV blood flow of the subject. The pressure sensor 75 is configured to measure the IRCAV blood pressure of the subject by measuring the blood pressure in the blood pressure measuring tube. In some applications (e.g., when used with the blood pump catheter 20 as shown in Figures 1A-1C), the renal vein pressure is measured in a generally similar manner (e.g., with a blood pressure measuring tube that defines an opening located near the junction of the renal vein and the vena cava). In some applications, the computer processor 10 receives an indication of the measured blood pressure and controls the pumping of the blood pressure by the impeller in response to the measured blood pressure. In some applications (e.g., when used with blood pump catheter 70), the computer processor adjusts blood flow (e.g., as described above) from the infrarenal vena cava blood flow 84 to the adrenal vena cava blood flow 86 in response to the measured blood pressure. In some applications (e.g., when used with blood pump catheter 20 as shown in Figures 1A and 1B), the computer processor adjusts the diameter to which occlusion element 40 expands in response to the measured blood pressure.

[0098] Typically, there is a relationship between the amount of power required to power the impeller to rotate at a given rotational speed and the pressure differential the impeller creates. (Typically, the impeller reduces the pressure in the vena cava region upstream of the material 36 by pumping blood pressure into the vena cava region downstream of the material 36, thereby reducing the blood pressure in the upstream region and creating a pressure differential between the upstream and downstream regions.) In some applications, a calibration measurement is performed so that the relationship between (a) the power consumption by the motor required to rotate the impeller at a given rotational speed and (b) the pressure differential the impeller creates is known.

[0099] In some applications, the blood pressure upstream of the impeller 50 and covering material 36 is measured, for example, using a blood pressure measurement tube that defines an opening 83 in the outer tube 77 at its distal end, and / or using a pressure sensor (e.g., a piezoelectric pressure sensor and / or an optical sensor) placed in an infrarenal position in the vena cava. In some such applications, the blood pressure downstream of the impeller 50 and covering material 36 is then calculated by a computer processor based on (a) the measured upstream blood pressure, (b) the power consumption by the motor required to rotate the impeller at a given rotational speed at that time, and (c) a predetermined relationship between the power consumption by the motor required to rotate the impeller at a given rotational speed and the pressure difference generated by the impeller. In some applications, the above technique is performed while maintaining the rotational speed of the impeller at a constant speed. Alternatively or additionally, the rotational speed of the impeller is varied and the variation in the rotational speed of the impeller is taken into account in the above calculation.

[0100] Typically, the blood outlet opening 31 of the material 36 has a known cross-sectional area. In some applications, the flow generated by the impeller through the blood outlet opening is determined based on the determined pressure differential generated by the impeller and the known cross-sectional area of ​​the opening. In some applications, such flow calculations incorporate calibration parameters to take into account factors such as the flow resistance inherent to the blood pump catheter (or type of blood pump catheter) for which the calculations are performed.

[0101] In some applications, the above-described devices and methods for measuring blood pressure are used, mutatis mutandis, with blood pump catheter 20 described above with reference to Figures 1A-1C, with blood pump catheter 70 described above with reference to Figures 2A-2F, with blood pump catheter 90 described below with reference to Figures 3A-3B, and / or with blood pump catheter 20 described below with reference to Figures 4A-4B.

[0102] Reference is now made to FIG. 2D, which is a schematic diagram of a blood pump catheter 70 placed in a subject's vena cava 22, according to some applications of the present invention. The blood pump has a non-axisymmetric outflow tube 76. The blood pump catheter 70 as shown in FIG. 2D is generally similar to that shown and described with reference to FIGS. 2A to 2C. However, the example blood pump catheter shown in FIG. 2A to 2C included two tubes 76, disposed on either side of the longitudinal axis of the blood pump catheter, extending from the tube 74 to an adrenal position, bypassing the blood pump 24. In contrast, the example blood pump catheter shown in FIG. 2D includes only one tube 76, disposed on one side of the longitudinal axis of the blood pump catheter, extending from the tube 74 to an adrenal position, bypassing the blood pump 24, according to some applications of the present invention. In other respects, the blood pump catheter 70 shown in FIG. 2D is generally similar to that shown and described with reference to FIGS. 2A to 2C. In some applications (not shown), the blood pump catheter includes three or more tubes 76 positioned at respective locations around the longitudinal axis of the blood pump catheter, extending from tube 74 to an adrenal location, bypassing blood pump 24.

[0103] Reference is now made to FIG. 2E, which is a schematic illustration of a blood pump catheter 70 placed in a subject's vena cava 22, according to some applications of the present invention. The blood pump has a non-axisymmetric outflow tube 76 and a non-axisymmetric blood pump 24. Reference is also made to FIG. 2F, which is a schematic illustration of the blood pump catheter of FIG. 2E without the subject's anatomy, according to some applications of the present invention. As described above with reference to FIG. 2D, in some applications, the blood pump catheter includes only one tube 76 that extends from the tube 74 to a suprarenal position, bypassing the blood pump 24, on one side of the longitudinal axis of the blood pump catheter. In some such applications, the blood pump 24 is positioned in a non-axisymmetric position on the opposite side of the longitudinal axis of the blood pump catheter, as shown. In other respects, the blood pump catheter 70 shown in FIG. 2E and FIG. 2F is generally similar to that shown and described with reference to FIG. 2A to FIG. 2D.

[0104] 2A-2E are performed in the absence of blood pump 24. That is, in the absence of blood pump 24, blood flow in a region of the vena cava adjacent the junction of the vena cava with the renal vein is separated into a separate compartment 82 from the infrarenal vena cava blood flow 84 and the adrenal vena cava blood flow 86. In some such applications, blood flow from the infrarenal vena cava blood flow 84 to the adrenal vena cava blood flow 86 is passively controlled (e.g., as described above) without affecting blood flow from the renal vein to the adrenal vena cava blood flow 86. Alternatively or additionally, blood flow from the renal vein to the adrenal vena cava blood flow 86 is passively controlled without affecting blood flow from the infrarenal vena cava blood flow 84 to the adrenal vena cava blood flow 86.

[0105] With respect to Figures 2A to 2E, it should be noted that the scope of the present invention includes the application of similar devices and methods to any venous system of a subject, including tributary veins that drain into a major vein. For example, similar techniques can be applied at the junction of the hepatic vein and the vena cava. Typically, such methods include isolating blood flow in a region of the major vein adjacent to the junction of the major vein and the tributary vein from blood flow in the major vein upstream and downstream thereof, pumping blood from a region of the major vein adjacent to the junction of the vein and the tributary vein to a location in the major vein downstream of the tributary vein using a pump, and directing the subject's blood to flow from a location in the major vein upstream of the tributary vein to a location in the major vein downstream of the tributary vein by directing the blood to bypass the pump without pumping with the pump. In some such applications, generally similar devices and methods are used at the junction of a vein and a lymphatic vessel in the subclavian or jugular vein. In some such applications, the blood pump catheter 70 is configured, mutatis mutandis, to increase lymphatic flow from the lymphatic vessel into the vein. In general, the scope of some applications of the present invention further includes devices and methods for use with a subject's venous system that includes a tributary vessel (e.g., lymphatic vessel) that drains into a vein. Typically, such methods include isolating flow in a region of the vein adjacent a junction between the vein and the tributary vessel from blood flow in the vein upstream and downstream thereof, pumping blood from a region of the vein adjacent the junction between the vein and the tributary vessel to a location in the vein downstream of the region using a pump, and directing the subject's blood to flow from a location in the vein upstream of the tributary vessel to a location in the vein downstream of the tributary vessel without pumping with the pump, by directing the blood to bypass the pump.

[0106] In some applications, such a method includes at least partially occluding blood flow through a vein by placing a downstream occlusion element (such as material 36) at a downstream location downstream of the junction of the vein and the tributary vessel, pumping blood with a pump from a region of the vein adjacent the junction of the vein and the tributary vessel through the downstream occlusion element, and directing upstream venous blood flow from an upstream location upstream of the junction of the vein and the tributary vessel to a location downstream of the occlusion element without pumping the upstream venous blood flow by bypassing the pump. Typically, such a method is performed using a blood pump catheter (such as blood pump catheter 70) including material 36. Material 36 is configured to be placed at a downstream location downstream of the junction of the vein and the tributary vessel and to at least partially occlude blood flow through the vein at the downstream location. The material defines a blood outlet opening 31. Blood pump 24 is typically configured to pump blood from a region of the vein adjacent the junction of the vein and the tributary vessel through the blood outlet opening defined by the material. The blood flow pathway 60 typically passes between a pathway inlet opening 61 located at an upstream location upstream of the junction of the vein and the tributary vessel, and a pathway outlet opening 63 that opens to the downstream side of the material 36. In some applications, the blood flow pathway includes a funnel 72 and one or more tubes (e.g., tubes 74 and 76). The funnel 72 is configured to be located at an upstream location upstream of the junction of the vein and the tributary vessel, and the one or more tubes 74, 76 are configured to extend from the funnel to the downstream side of the material. The funnel and one or more tubes (or alternative blood flow pathway) are configured to direct upstream venous blood flow from the upstream location to the downstream side of the material without pumping by a pump. Typically, as shown in FIG. 2A, the funnel 72 defines a wide end 85 and a narrow end 87. The wide end of the funnel typically defines an entrance opening to the blood flow pathway, and the narrow end of the funnel extends into one or more tubes (eg, tubes 74 and 76).

[0107] Reference is now made to Figures 3A, 3B, 3C, 3D, 3E, 3F, 3G, and 3H, which are schematic diagrams of a blood pump catheter 70 according to some alternative applications of the present invention. The blood pump catheter 70 shown and described with reference to Figures 3A to 3H is generally similar to that described with reference to Figures 2A to 2F, except for the differences described below. It should be noted that as shown in Figures 3A to 3H, the blood pump catheter has a generally similar design to that shown in Figures 2E and 2F (i.e., (a) only one tube 76 is disposed on one side of the longitudinal axis of the blood pump catheter, and extends from the tube 74 to the adrenal position, bypassing the blood pump 24; (b) the blood pump 24 is disposed in a non-axisymmetric position on the opposite side of the longitudinal axis of the blood pump catheter). However, the scope of the present application includes combining, mutatis mutandis, the features of the blood pump catheter 70 described with reference to Figures 3A to 3H with any one of the blood pump catheter 70 designs described above with reference to Figures 2A to 2D.

[0108] 3A, in some applications, the elongated tube 109 extends from the frame 34 to the subject's pulmonary artery 110 such that the blood outlet opening 31 is disposed in the pulmonary artery. (Note that in some applications, the material 36 defines the blood outlet opening, and the elongated tube extends from the material-defined blood outlet opening to a blood outlet opening disposed in the pulmonary artery.) The tube 109 is typically made of a blood impermeable material. For example, the tube 109 may include polyurethane, polyester, and / or silicone. Alternatively or additionally, the tube is made of polyethylene terephthalate (PET) and / or polyether block amide (e.g., PEBAX®). The blood pump catheter is configured to pump blood directly from the compartment 82 into the subject's pulmonary artery. In this manner, the blood pump catheter reduces renal vein pressure without increasing preload on the subject's right atrium. 2A-2F, typically blood flow from the IRC vena cava blood flow 84 to the adrenal vena cava blood flow 86 bypasses the elongated tubing. Typically blood flow from the IRC vena cava blood flow 84 to the adrenal vena cava blood flow 86 occurs passively by flowing through blood flow pathway 60 (e.g., funnel 72, tube 74, and one or more tubes 76).

[0109] 3B, in some applications, the elongated tube 109 includes a portion 111 disposed within the adrenal vena cava blood flow 86 to define an adrenal blood inlet opening 112. The impeller 50 and frame 34 are typically disposed downstream of the adrenal blood inlet opening, and the impeller is configured to pump blood from the adrenal vena cava blood flow into the elongated tube 109 via the blood inlet opening 112, in addition to pumping blood from the compartment 82 into the elongated tube 109. As described with reference to FIG. 3A, the elongated tube 109 typically extends from the frame 34 to a pulmonary artery 110 of the subject, such that the blood outlet opening 31 is disposed within the pulmonary artery. The blood pump catheter 70 as configured in FIG. 3B is typically configured to reduce renal vein pressure (by pumping blood from the compartment 82) and to support right heart function of the subject by pumping blood from the adrenal vena cava blood flow to the pulmonary artery. 2A-2F, typically blood flow from the IRC vena cava blood flow 84 to the adrenal vena cava blood flow 86 bypasses the elongated tubing. Typically blood flow from the IRC vena cava blood flow 84 to the adrenal vena cava blood flow 86 occurs passively by flowing through blood flow pathway 60 (e.g., funnel 72, tube 74, and one or more tubes 76).

[0110] 3C, in some applications, in addition to reducing renal vein pressure with blood pump catheter 70 (and, optionally, supporting right heart function as described with reference to FIG. 3B), a left ventricular assist device 113 is positioned within a subject's left ventricle 114 to assist left heart function in the subject. In some applications, the left ventricular assist device is a left ventricular assist device as described in U.S. Patent Application Publication No. 16 / 750,354 to Tuval (filed Jan. 23, 2020, entitled "Distal tip element for a ventricular assist device"), U.S. Patent Application Publication No. 2019 / 0209758 to Tuval, and / or U.S. Patent Application Publication No. 2019 / 0175806 to Tuval, all of which are incorporated herein by reference. In some applications, the left ventricular assist device includes a left ventricular assist device manufactured by Abiomed® (Massachusetts, USA), such as the Impella2.5®, ImpellaCP®, Impella5.5®, and / or Impella5.0®. It should be noted that while the left ventricular assist device 113 is shown as being used in combination with the example blood pump catheter 70 shown in FIG. 3B, the scope of the present application includes the use of the left ventricular assist device 113 in combination with any of the example blood pump catheters 70 described herein.

[0111] 3D, in some applications, instead of the impeller 50 and frame 34, an elongated blood pump tube 104 (typically including an impeller) is disposed within the blood outlet opening of the covering material 36. Typically, the covering material 36 and / or inner lining 39 (FIG. 7) are sealingly bonded to the outer surface of the elongated blood pump tube. For example, the elongated blood pump tube may include Impella RP® manufactured by Abiomed (Massachusetts, USA). Typically, the elongated blood pump tube includes a blood inlet area 105 (located within an upstream portion of the elongated blood pump tube), which is disposed at a lower (i.e., upstream) position relative to the covering material 36 and / or inner lining 39 (FIG. 7). An impeller 106 (typically located in close proximity to and distal to the blood inlet area) pumps blood from the compartment 82 into the blood inlet area and out of the blood outlet area 107 (located in a downstream portion of the elongated blood pump tube) via the elongated blood pump tube. In the example shown in FIG. 3A, the blood outlet area is located in the suprarenal vena cava, such that blood is pumped into the suprarenal vena cava blood flow 86. As described in FIGS. 2A-2F, typically, blood flow from the renal inferior vena cava blood flow 84 to the suprarenal vena cava blood flow 86 bypasses the elongated blood pump tube. Typically, blood flow from the renal inferior vena cava blood flow 84 to the suprarenal vena cava blood flow 86 occurs passively by flowing through the blood flow pathway 60 (e.g., the funnel 72, the tube 74, and one or more tubes 76).

[0112] 3E, in some applications, the elongated blood pump tube 104 is positioned such that the blood inlet area 105 and the impeller 106 are located within the adrenal vena cava. In some such applications, a reinforced tube 115 (e.g., a tube made of a polymer supported by a shape memory material (e.g., Nitinol) frame and / or a shape memory material (e.g., Nitinol) braid) extends from the outlet opening of the covering material 36 and / or the inner lining 39 (FIG. 7) to the blood inlet area of ​​the elongated blood pump tube, forming a seal between the covering material 36 and / or the inner lining 39 and the blood inlet area of ​​the elongated blood pump tube. In this manner, the impeller 106 draws blood from the compartment 82 into the blood inlet area 105. Typically, the elongated blood pump tube extends from the blood inlet area to a blood outlet area 107 located within the pulmonary artery 110 of the subject. In some alternative applications (not shown), the elongated blood pump tube itself extends from upstream of the covering material 36 to the pulmonary artery 110 (i.e., the reinforced tube 115 is not present). The elongated blood pump tube is configured to pump blood from the compartment 82 into the subject's pulmonary artery. In this manner, the blood pump catheter 70 reduces renal vein pressure without increasing preload on the subject's right atrium. As depicted in Figures 2A-2F, typically, blood flow from the renal inferior vena cava blood flow 84 to the adrenal vena cava blood flow 86 bypasses the elongated blood pump tube. Typically, blood flow from the renal inferior vena cava blood flow 84 to the adrenal vena cava blood flow 86 occurs passively by flowing through the blood flow pathway 60 (e.g., the funnel 72, the tube 74, and one or more tubes 76).

[0113] 3F, in some applications, the reinforced tube 115 defines a blood inlet opening 117 that is disposed within the adrenal vena cava. The impeller 106 and blood inlet area 105 are typically disposed downstream of the blood inlet opening 117, and the impeller is configured to pump blood from the adrenal vena cava blood flow into the elongated blood pump tube 104 via the blood inlet opening 117, in addition to pumping blood into the elongated blood pump tube 104. As described with reference to FIG. 3E, the elongated blood pump tube 104 typically extends from the adrenal vena cava to the subject's pulmonary artery 110, such that the blood outlet area 107 is disposed within the pulmonary artery. The blood pump catheter 70 as configured in FIG. 3F is typically configured to reduce renal vein pressure (by pumping blood from the compartment 82) and to support the subject's right heart function by pumping blood from the adrenal vena cava blood flow to the pulmonary artery. 2A-2F, typically blood flow from the IRC vena cava blood flow 84 to the adrenal vena cava blood flow 86 bypasses the elongated blood pump tubing. Typically blood flow from the IRC vena cava blood flow 84 to the adrenal vena cava blood flow 86 occurs passively by flowing through blood flow pathway 60 (e.g., funnel 72, tube 74, and one or more tubes 76).

[0114] 3G, in some applications, the blood inlet opening 117 is disposed in the right ventricle 119 of the subject, and the impeller 106 and blood inlet area 105 are disposed downstream of the blood inlet opening. In addition to pumping blood into the elongated blood pump tube 104, the impeller is configured to pump blood from the right ventricle into the elongated blood pump tube 104 through the blood inlet opening 117. Typically, the elongated blood pump tube 104 extends from the right ventricle to the pulmonary artery 110 of the subject, such that the blood outlet area 107 is disposed in the pulmonary artery. The blood pump catheter 70 as configured in FIG. 3G is typically configured to reduce renal vein pressure (by pumping blood from the compartment 82) and to support the right heart function of the subject by pumping blood from the right ventricle to the pulmonary artery. As described in FIG. 2A to FIG. 2F, typically, blood flow from the inferior renal vena cava blood flow 84 to the adrenal vena cava blood flow 86 bypasses the elongated blood pump tube. Typically, blood flow from the inferior renal vena cava blood flow 84 to the adrenal vena cava blood flow 86 occurs passively by flowing through the blood flow pathway 60 (eg, funnel 72, tube 74, and one or more tubes 76).

[0115] 3H, in some applications, a blood pump catheter 70 includes an elongated blood pump tube 104 (e.g., according to any of the examples described with reference to FIGS. 3D-3G), and the blood pump catheter is used with a left ventricular assist device 113 deployed in a left ventricle 114 of a subject to assist left heart function (e.g., as described above with reference to FIG. 3C). In some applications, the left ventricular assist device is a left ventricular assist device as described in U.S. Patent Application Publication No. 16 / 750,354 to Tuval (filed January 23, 2020, entitled "Distal tip element for a ventricular assist device"), U.S. Patent Application Publication No. 2019 / 0209758 to Tuval, and / or U.S. Patent Application Publication No. 2019 / 0175806 to Tuval, all of which are incorporated herein by reference. In some applications, the left ventricular assist device includes a left ventricular assist device manufactured by Abiomed® (Massachusetts, USA), such as the Impella2.5®, ImpellaCP®, Impella5.5®, and / or Impella5.0®. It should be noted that while the left ventricular assist device 113 is shown as being used in combination with the example blood pump catheter 70 shown in FIG. 3F, the scope of the present application includes the use of the left ventricular assist device 113 in combination with any of the example blood pump catheters 70 described herein.

[0116] Reference is now made to Figures 4A and 4B, which are schematic illustrations of a blood pump catheter 90 placed in a subject's descending aorta 80 near the subject's renal arteries 94, in accordance with certain applications of the present invention. The structure of the blood pump catheter 90 is generally similar to that of the blood pump catheter 70 described above with reference to Figures 2A-2F. However, the blood pump 24 of the blood pump catheter 90 is typically configured to pump blood upstream to increase perfusion of tissue (such as the kidneys), as described in more detail below.

[0117] Typically, the blood pump catheter 90 includes a blood pump 24 that typically includes an impeller housing 26 and an impeller 50, all generally similar to those described above. The impeller housing 26 (e.g., housing frame 34) typically functions to separate the inner wall of the aorta from the impeller so that the aorta is not damaged by the impeller and so that the impeller is not deformed by pressure from the inner wall of the aorta. Also, an axial shaft 92 (shown in FIG. 7) that passes through the impeller is typically supported by radial bearings 116, 118 located at the proximal and distal ends of the impeller housing, respectively.

[0118] In some such applications, the blood pump support frame 32 is disposed upstream of the impeller housing 26 and configured to contact the inner wall of the aorta. The blood pump support frame 32 is configured to contact the inner wall of the aorta to align the longitudinal axis of the impeller housing 26, and thereby the impeller 50, with the local longitudinal axis of the aorta. (It should be noted that in some applications, the blood pump support frame may not perfectly align the longitudinal axis of the impeller with the local longitudinal axis of the aorta. Typically, however, the blood pump support frame maintains the longitudinal axis of the impeller in better alignment with the local longitudinal axis of the aorta than the longitudinal axis of the impeller would be in the absence of the blood pump support frame.) Typically, other things being equal, the greater the effectiveness of pumping blood by the impeller 50, the better the alignment of the longitudinal axis of the impeller with the local longitudinal axis of the aorta. As noted above, it should nevertheless be noted that even slight misalignment between the longitudinal axis of the impeller and the local longitudinal axis of the vessel in which it is located (as shown, for example, in FIG. 2E) typically results in effective pumping of blood by the impeller.

[0119] In some applications, the impeller housing 26 includes a frame 34 (e.g., a rigid or semi-rigid frame) made of a shape memory element (such as Nitinol) that is at least partially coated with a material 36 (e.g., a blood impermeable material such as polyester, polyurethane, and / or a different polymer). Typically, in such applications, the frame 34 is sufficiently rigid that it does not deform due to pressure exerted by the inner wall of the aorta on the frame 34. Typically, the material 36 extends from the impeller housing to the blood pump support frame 32 to contact the vessel wall and occlude the vessel in a region of the vessel surrounding and / or upstream of the impeller. The material typically defines a through hole in a distal portion of the impeller housing. The hole is configured to act as a blood inlet opening 98 during pumping of blood by the impeller. In some applications, a portion of the impeller housing is covered (i.e., lined) on the inside of the impeller housing with an inner lining 39, for example, as described below with reference to Figure 7. In some such applications, the inner lining of the impeller housing at least partially overlaps material 36. In some applications, the inner lining extends the blood inlet opening defined in material 36.

[0120] Typically, a drive cable 78 is disposed within an outer tube 77 of the blood pump catheter 90 (the drive cable is shown, for example, in FIG. 8A). Typically, the drive cable extends from a motor 79 disposed outside the subject's body to an axial shaft 92 (shown in FIG. 7) on which the impeller is disposed. The motor provides rotational motion to the axial shaft (and thereby to the impeller) via the drive cable. Typically, the motor is controlled by a computer processor 10. In some applications, the motor is controlled based on blood pressure measurements performed by a pressure sensor 75.

[0121] In some applications, the blood pump catheter further includes a blood flow path 60. In some applications, the blood flow path 60 includes a funnel 72 extending into a tube 74. The funnel is configured to be placed upstream of the junction of the aorta and the subject's renal artery and configured to direct all blood flow from the suprarenal aorta into the tube 74. The tube 74 then directs blood flow from the suprarenal aorta location to an infrarenal aorta location such that this blood bypasses the blood pump 24 (i.e., is not pumped by the blood pump 24) and flows to the infrarenal location. For example, one or more tubes 76 may extend from the tube 74 to an infrarenal location while bypassing the blood pump. As shown by the blood flow arrows in FIG. 4A, this allows blood to flow from the suprarenal aorta to the infrarenal aorta without being pumped by the blood pump 24. In contrast, as shown by the blood flow arrows in FIG. 4B, blood is pumped from the infrarenal aorta to the renal artery 94 by the blood pump 24. Typically, pumping blood into the renal arteries increases renal perfusion.

[0122] Thus, by deploying blood pump catheter 90, blood flow in the region of the aorta adjacent the junction of the aorta and the renal arteries is separated into a compartment 97 separate from the suprarenal aortic blood flow 95 and the infrarenal aortic blood flow 99. Blood flow from the suprarenal aortic blood flow 95 to the infrarenal aortic blood flow 99 occurs passively (e.g., by flowing through blood flow pathway 60). Blood is actively pumped from the infrarenal aortic blood flow 99 to compartment 97 using a blood pump.

[0123] It should be noted that the specific configurations of funnel 72, tube 74, and tube 76 are shown by way of example only, and the scope of the present application includes, mutatis mutandis, the use of any other configuration of blood flow pathways for directing blood from the suprarenal aortic blood flow to the infrarenal aortic blood flow without pumping with blood pump 24. In some applications, funnel 72, tube 74, and tube 76 comprise portions of a single continuous blood flow pathway. The blood flow pathway typically passes between a pathway inlet opening 61 located at an upstream location upstream of the junction of the aorta and the renal arteries, and a pathway outlet opening 63 that opens onto the downstream side of material 36. Typically, funnel 72 defines a wide end 85 and a narrow end 87. The wide end of the funnel typically defines an inlet opening to the blood flow pathway, and the narrow end of the funnel extends into one or more tubes (e.g., tubes 74 and 76).

[0124] Typically, the blood flow from the suprarenal aortic blood flow 95 to the infrarenal aortic blood flow 99 is not substantially changed compared to the blood flow from the suprarenal aortic blood flow 95 to the infrarenal aortic blood flow 99 in the absence of the blood pump catheter. In some applications, the blood flow from the suprarenal aortic blood flow 95 to the infrarenal aortic blood flow 99 is controlled by controlling the diameter of one or more portions of the blood flow pathway. For example, the diameter of one or more portions of the blood flow pathway (e.g., funnel 72, tube 74, and / or one or more tubes 76) may be adjusted (e.g., using an inflatable / contractable component disposed on or outside one of these portions). In this manner, the blood supply to, for example, the lower body, may be controlled.

[0125] With respect to Figures 4A-4B, it should be noted that the scope of the present invention includes the application of similar devices and methods to any arterial system of a subject that includes a main artery that flows into a branch artery (typically supplying tissue). For example, similar techniques can be applied at the junction of the aorta and hepatic artery (supplying the liver). Typically, such methods include isolating blood flow in a region of the main artery adjacent to the junction of the main artery and the branch artery from blood flow in the main artery upstream and downstream thereof, using a pump to pump blood from the main artery to a region of the main artery adjacent to the junction of the main artery and the branch artery to increase perfusion of the tissue, and directing the subject's blood to flow from a location in the main artery upstream of the branch artery to a location in the main artery downstream of the branch artery without pumping it with a pump, by bypassing the pump. In some applications, such a method includes at least partially occluding blood flow through a main artery by placing a downstream occlusion element (e.g., material 36) at a downstream location downstream of the junction of the main artery and the branch artery, increasing tissue perfusion by pumping blood with a pump (e.g., blood pump 24) from a region of the main artery adjacent the junction of the main artery and the branch artery through the downstream occlusion element, and directing upstream main artery blood flow from an upstream location upstream of the junction of the main artery and the branch artery to downstream of the occlusion element by directing the upstream main artery blood flow to bypass the pump without being pumped by the pump. Typically, a blood pump catheter such as blood pump catheter 90 including material 36 is used. Material 36 is configured to be placed at a downstream location downstream of the junction of the main artery and to at least partially occlude blood flow through the main artery at the downstream location. The material defines a blood inlet opening 98. Blood pump 24 is typically configured to pump blood from the main artery toward a region of the main artery adjacent the junction of the main artery and the branch artery through the blood inlet opening. Blood flow pathway 60 typically passes between a pathway inlet opening 61 located at an upstream position upstream of the junction of the main artery and the branch artery, and a pathway outlet opening 63 that opens onto the downstream side of material 36.In some applications, the blood flow pathway includes a funnel 72 and one or more tubes (e.g., tubes 74 and 76). The funnel 72 is configured to be positioned at an upstream location upstream of the junction of the main artery and the branch artery, and the one or more tubes 74, 76 (or alternative blood flow pathways) are configured to extend from the funnel to a downstream side of the material. The funnel and one or more tubes (or alternative blood flow pathways) are typically configured to direct upstream main arterial blood flow from the upstream location to a downstream side of the material without pumping by a pump. Typically, the funnel 72 defines a wide end 85 and a narrow end 87. The wide end of the funnel typically defines an entrance opening to the blood flow pathway, and the narrow end of the funnel extends into one or more tubes (e.g., tubes 74 and 76).

[0126] Reference is now made to Figures 5A-5B, which are schematic diagrams of a blood pump catheter 20 placed in a subject's descending aorta 80, in accordance with some applications of the present invention. Typically, the blood pump catheter 20 is generally as described above, and includes a blood pump 24, which typically includes an impeller housing 26 and an impeller 50, all generally similar to those described above. The impeller housing 26 (e.g., housing frame 34) typically functions to separate the inner wall of the aorta from the impeller, so that the aorta is not damaged by the impeller and the impeller is not deformed by pressure from the inner wall of the aorta. Also, typically, an axial shaft 92 (shown in Figure 7) that passes through the impeller is supported by radial bearings 116, 118 located at the proximal and distal ends of the impeller housing, respectively.

[0127] In some such applications, the blood pump support frame 32 is disposed upstream of the impeller housing 26 and is configured to contact the inner wall of the aorta such that the blood pump support frame 32 is configured to contact the inner wall of the aorta to align the longitudinal axis of the impeller housing 26, and thereby the impeller 50, with the local longitudinal axis of the aorta. (It should be noted that in some applications, the blood pump support frame may not perfectly align the impeller's longitudinal axis with the local longitudinal axis of the aorta. Typically, however, the blood pump support frame maintains the impeller's longitudinal axis in better alignment with the local longitudinal axis of the aorta than the impeller's longitudinal axis would be in the absence of the blood pump support frame.) Typically, other things being equal, the greater the effectiveness of impeller 50 in pumping blood, the better the alignment of the impeller's longitudinal axis with the local longitudinal axis of the aorta.

[0128] In some applications, the impeller housing 26 includes a frame 34 (e.g., a rigid or semi-rigid frame) made of a shape memory element (such as Nitinol) that is at least partially coated with a material 36 (e.g., a blood impermeable material such as polyester, polyurethane, and / or a different polymer). Typically, in such applications, the frame 34 is sufficiently rigid that it does not deform due to pressure exerted by the inner wall of the aorta on the frame 34. Typically, the material 36 extends from the impeller housing to the blood pump support frame 32 to contact the vessel wall and to occlude the vessel in a region of the vessel surrounding and / or upstream of the impeller. The material typically defines a through hole in a distal portion of the impeller housing. The material is configured to occlude retrograde blood flow around the outside of the impeller, but allow antegrade blood flow in a central region of the vessel near the impeller, with holes acting as blood exit openings 31. In some applications, a portion of the impeller housing is covered (i.e., lined) on the inside of the impeller housing with an inner lining 39, for example, as described below with reference to FIG. 7. In some such applications, the inner lining of the impeller housing at least partially overlaps with material 36. In some applications, the inner lining extends the blood exit opening defined in material 36.

[0129] Typically, a drive cable 78 is disposed within an outer tube 77 of the blood pump catheter 90 (the drive cable is shown, for example, in FIG. 8A). Typically, the drive cable extends from a motor 79 disposed outside the subject's body to an axial shaft 92 (shown in FIG. 7) on which the impeller is disposed. The motor provides rotational motion to the axial shaft (and thereby to the impeller) via the drive cable. Typically, the motor is controlled by a computer processor 10. In some applications, the motor is controlled based on blood pressure measurements performed by a pressure sensor 75. The covering material 36 essentially separates the descending aorta into two compartments, and the blood pump pumps blood from the upstream compartment to the downstream compartment. In this manner, the blood pump typically increases aortic blood flow and / or reduces left ventricular afterload.

[0130] With reference to Figure 5A, in some applications, the blood pump is inserted into the descending aorta via an artery lower than the descending aorta, such as the femoral artery. Alternatively or additionally, as shown in Figure 5B, the blood pump is inserted into the descending aorta via an artery higher than the descending aorta, such as the radial artery or the subclavian artery. In some applications, the blood pump catheter is, mutatis mutandis, inserted into the subject's aortic arch rather than the descending aorta.

[0131] In some applications, the impeller 50, impeller housing 26, frame 34, and / or other components of the blood pump catheters described herein have similar features to those described in U.S. Patent Application Publication No. 16 / 750,354 to Tuval (filed January 23, 2020, and entitled "Distal tip element for a ventricular assist device"), U.S. Patent Application Publication No. 2019 / 0209758 to Tuval, U.S. Patent Application Publication No. 2019 / 0239998 to Tuval, and / or U.S. Patent Application Publication No. 2019 / 0175806 to Tuval, all of which are incorporated herein by reference. For example, some of these features are described below with reference to Figures 6A-8C.

[0132] Reference is now made to Figures 6A to 6C, which are schematic illustrations of an impeller 50 and a portion thereof according to some applications of the present invention. Typically, the impeller includes at least one outer helical elongated element 52 wound around a central axial spring 54, such that the helical shape defined by the helical elongated element is coaxial with the central axial spring. Typically, the impeller includes two or more helical elongated elements (e.g., three helical elongated elements as shown in Figures 6A to 6C). In some applications, the helical elongated element and the central axial spring are made of a shape memory material, such as a shape memory alloy, such as Nitinol. Typically, each of the helical elongated element and the central axial spring supports a film 56 of material (e.g., an elastomer, such as polyurethane and / or silicone) between them. In some applications, the film of material includes a piece of Nitinol embedded therein, for example to strengthen the film of material. For illustrative purposes, the impeller is shown without material in Figure 6A. 6B and 6C each show a diagram of an impeller in which material is supported between a helical elongated element and a spring.

[0133] Each of the helical elongate elements, together with a film extending from the helical elongate element to the spring, defines an impeller vane. The helical elongate element defines the outer edge of the vane, and the axial spring defines the axis of the impeller. Typically, a film of material extends along and covers the spring. In some applications, the helical elongate element is wrapped with suture 53 (e.g., polyester suture shown in Figures 6B and 6C), as described, for example, in U.S. Patent Application Publication No. 2016 / 0022890 to Schwammenthal, which is incorporated herein by reference. Typically, the suture is configured to promote bonding between the film of material (typically an elastomer such as polyurethane or silicone) and the helical elongate element (typically a shape memory alloy such as Nitinol). In some applications, the spring 54 is wrapped with suture (e.g., polyester suture, not shown). Typically, the suture is configured to promote bonding between a film of material (typically an elastomer such as polyurethane or silicone) and a spring (typically a shape memory alloy such as Nitinol).

[0134] Close-ups A and B of FIG. 6C show two alternative ways of tying the sutures to the helical elongate element 52. In some applications, the sutures are tied to the outer surface of the helical elongate element, as shown in close-up A. Alternatively, the helical elongate element defines grooves 48 on its outer surface, and the sutures are embedded within these grooves, as shown in close-up B. By embedding the sutures within the grooves, the sutures do not generally expand the outer shape of the impeller, which is defined by the outer surface of the helical elongate element.

[0135] Typically, the proximal ends of the spring 54 and the helical elongate element 52 extend from an impeller proximal bushing (i.e., sleeve bearing) 64 such that they are disposed at similar radial distances from the longitudinal axis of the impeller relative to one another. Similarly, the distal ends of the spring 54 and the helical elongate element 52 typically extend from an impeller distal bushing 58 such that they are disposed at similar radial distances from the longitudinal axis of the impeller relative to one another. Typically, the impeller spring 54 and the proximal and distal bushings 64, 58 define a lumen 62 therein (shown in FIG. 6C ).

[0136] Reference is now made to FIG. 7, which is a schematic diagram of an impeller 50 disposed within a frame 34 of a blood pump catheter 20, 70, or 90, according to some applications of the present invention. In some applications, an inner lining 39 lines the frame inside at least a portion of the frame 34. Depending on the respective application, the inner lining partially or completely overlaps the covering material 36 in the frame portion it lines. In the application shown in FIG. 7, the inner lining lines (i.e. covers) the inside of a cylindrical portion 38 of the frame, and the covering material 36 does not cover the cylindrical portion of the frame. In such applications, the inner lining extends the blood inlet or blood outlet opening of the blood pump.

[0137] 7, typically there is a gap G between the outer edge of the impeller 50 and the inner lining 39 even at the location where the impeller's span is greatest. In some applications, it is desirable for the gap between the outer edge of the impeller's blades and the inner lining 39 to be relatively small so that the impeller will pump blood efficiently. However, it is also desirable for the gap between the outer edge of the impeller's blades and the inner lining 39 to remain substantially constant throughout rotation of the impeller within the frame 34, for example to reduce the risk of hemolysis.

[0138] In some applications, when the impeller and frame 34 are both arranged in a radially unconstrained configuration, the gap G between the outer edge of the impeller and the inner lining 39 at the location where the impeller blade width is greatest is greater than 0.05 mm (e.g., greater than 0.1 mm) and / or less than 1 mm (e.g., less than 0.4 mm). For example, the gap G is between 0.05 and 1 mm, or between 0.1 and 0.4 mm. In some applications, when the impeller is arranged in a radially unconstrained configuration, the outer diameter of the impeller at the location where the outer diameter of the impeller is greatest is greater than 7 mm (e.g., greater than 8 mm) and / or less than 10 mm (e.g., less than 9 mm). For example, the outer diameter is between 7 and 10 mm, or between 8 and 9 mm. In some applications, when the frame 34 is disposed in a radially unconstrained configuration, the inner diameter of the cylindrical portion 38 of the frame 34 (measured from the inside of the inner lining 39 on one side of the frame to the inside of the inner lining on the opposite side of the frame) is greater than 7.5 mm (e.g., greater than 8.5 mm) and / or less than 10.5 mm (e.g., less than 9.5 mm). For example, the inner diameter is between 7.5 and 10.5 mm, or between 8.5 and 9.5 mm. In some applications, when the frame is disposed in a radially unconstrained configuration, the outer diameter of the cylindrical portion 38 of the frame 34 is greater than 8 mm (e.g., greater than 9 mm) and / or less than 13 mm (e.g., less than 12 mm). For example, the outer diameter is between 8 and 13 mm, or between 9 and 12 mm.

[0139] Typically, the axial shaft 92 passes through the axis of the impeller 50 through the impeller bore 62. More typically, the axial shaft is rigid, e.g., a rigid tube. In some applications, the impeller proximal bushing 64 is coupled to the shaft such that the axial position of the proximal bushing relative to the shaft is fixed, and the impeller distal bushing 58 is slidable relative to the shaft. The axial shaft itself is radially stabilized by a proximal radial bearing 116 and a distal radial bearing 118. (Note that in FIG. 7, the distal radial bearing 118 is not visible, since it is located below the distal end element 108. However, in other figures, e.g., in the embodiments shown in FIGS. 1A-1C, 2A-2E, and 4A-4B, the distal radial bearing is visible.) The axial shaft also extends through the bore 62 defined by the impeller, radially stabilizing the impeller against the inner surface of the frame 34 so that even a relatively small gap (such as that described above) between the outer edges of the impeller blades and the inner surface of the frame 34 is maintained during rotation of the impeller.

[0140] 6A-6C, in some applications, the impeller includes a plurality of elongated elements 67 extending from the central axial spring 54 to the outer helical elongated element 52. The elongated elements are typically flexible, but substantially inextensible along the axis they define. More typically, each of the elongated elements is configured to not apply a force to the helical elongated element unless a force acts on the impeller to move the helical elongated element radially outward such that the separation between the helical elongated element and the central axial spring (in the absence of the elongated element) is greater than the length of the elongated element. For example, the elongated elements may include threads (such as polyester and / or another polymer, or natural material including fibers) and / or wires (such as Nitinol wires and / or wires made of different alloys or metals).

[0141] In some applications, the elongated elements 67 maintain the helical elongated elements (which define the outer edges of the impeller vanes) within a given distance relative to the central axial spring. In this manner, the elongated elements are configured to prevent the outer edges of the impeller from being forced radially outward by forces applied to the impeller during rotation of the impeller. The elongated elements are thereby configured to maintain a gap between the outer edges of the impeller vanes and the inner lining 39 of the frame 34 during rotation of the impeller. Typically, two or more (e.g., three or more) and / or seven or fewer (e.g., three or fewer) elongated elements 67 are used in an impeller, with each elongated element typically being doubled (i.e., extending radially from the central axial spring 54 to the outer helical elongated element 52 and then back from the helical elongated element to the central axial spring). In some applications, multiple elongate elements are formed from a single thread or wire, with each elongate element extending from a spring to a helical elongate element and then back to the spring, as described in more detail below.

[0142] In some applications, the impeller is manufactured as follows: The proximal bushing 64, the distal bushing 58, and the helical elongate element 52 are cut from a tube of shape memory material, such as Nitinol. The cutting of the tube and the shape setting of the shape memory material are typically performed using techniques generally similar to those described, for example, in U.S. Patent Application Publication No. 2016 / 0022890 to Schwammenthal, such that the helical elongate element is defined by the shape memory material. Typically, a spring 54 is inserted into the cut and shape set tube such that the spring extends along the length of the tube from at least the proximal bushing to the distal bushing. In some applications, the spring is inserted into the cut and shape set tube in an axially compressed state and configured to be held in place relative to the tube by applying a radial force to the proximal and distal bushings. Alternatively or additionally, portions of the spring are welded to the proximal and distal bushings. In some applications, the spring is cut from a tube of shape memory material, such as Nitinol. In some such applications, the spring is configured such that when the spring is disposed in a radially unconstrained configuration (as the spring is typically disposed during operation of the impeller), there are substantially no gaps between adjacent windings of the spring.

[0143] In some applications, after the spring 54 is inserted into the tube cut and shaped as described above, the elongated element 67 described above is placed to extend between the spring and one or more of the helical elongated elements. This can be done, for example, as follows: A mandrel (e.g., a polyetheretherketone (PEEK) and / or polytetrafluoroethylene (PTFE) mandrel) is inserted into the lumen defined by the spring and the bushing. A thread or wire is then attached by (a) extending from the mandrel onto a first one of the helical elongated elements, (b) passing from the first one of the helical elongated elements back to the mandrel, (c) winding it around the mandrel, extending from the second one of the helical elongated elements, (d) passing from the second one of the helical elongated elements back to the mandrel, etc. Once the thread or wire has extended from the mandrel onto each of the helical elongated elements and then back, the ends of the thread or wire are joined together, for example, by tying them together. In some applications, the helical elongate element is wrapped with a suture 53 (e.g., polyester suture) to facilitate bonding between the film of material (typically an elastomer such as polyurethane or silicone) and the helical elongate element (typically a shape memory alloy such as Nitinol) in the next stage of impeller manufacturing. In some applications, the spring 54 is wrapped with a suture (e.g., polyester suture, not shown). Typically, the suture is configured to facilitate bonding between the film of material (typically an elastomer such as polyurethane or silicone) and the spring (typically a shape memory alloy such as Nitinol) in the next stage of impeller manufacturing.

[0144] Typically, at this stage, a structure 59 as shown in FIG. 6A is assembled. The structure includes cut and shaped tubes that define the proximal and distal bushings, the helical elongate element, and the spring (and optionally the elongate element and suture). The structure is dipped into the material that defines the film 56. In some applications, the assembled structure is dipped into the material with a mandrel placed in the lumen defined by the spring and bushing, although it should be noted that the mandrel is not shown in FIG. 6A. Typically, the material from which the film is made is silicone and / or polyurethane (and / or similar elastomers), and the assembled structure is dipped into the material while the material is in an uncured liquid state. This is then cured, for example by drying the material so that it becomes solid. Once the material is dry, the mandrel is typically removed from the lumen defined by the bushing and spring.

[0145] As a result of the above process, a continuous film of material typically extends between each of the helical elongate elements and the springs, and along the length of the springs, defining a tube with the springs embedded therein. The portions of the film extending from each of the helical elongate elements to the springs define impeller vanes. In applications where the impeller includes elongate elements 67, the elongate elements are typically embedded in these portions of the film.

[0146] Typically, the impeller 50 is inserted into the subject's body in a radially constrained configuration. In the radially constrained configuration, the helical elongated element 52 and the central axial spring 54 are both axially elongated and radially constrained. Typically, the film of material (e.g., silicone and / or polyurethane) 56 changes shape to match the shape change of the helical elongated element and the axial support spring (both supporting the film of material). Typically, using a spring to support the inner edge of the film allows the film to change shape without breaking or collapsing because the spring provides a large surface area for the inner edge of the film to bond to. In some applications, using a spring to support the inner edge of the film allows the impeller to be radially constrained to a smaller diameter than, for example, when a rigid shaft is used to support the inner edge of the film, since the diameter of the spring itself can be reduced by elongating the spring axially.

[0147] In some applications, the proximal bushing 64 of the impeller 50 is coupled to the axial shaft 92 such that the axial position of the proximal bushing relative to the shaft is fixed, and the distal bushing 58 of the impeller is slidable relative to the shaft. In some applications, when the impeller is radially constrained to insert the impeller into the subject's body or to withdraw the impeller from the subject's body, the distal bushing slides distally along the axial shaft, thereby axially lengthening the impeller. After release within the subject's body, the impeller is in a radially unconstrained configuration (as the impeller is typically positioned during operation), as shown in Figures 6A-6C.

[0148] It should be noted that for purposes of illustration, in some figures, impeller 50 is shown without all of the impeller features shown and described with respect to Figures 6A-6C, and the scope of the present application includes the use of an impeller having any of the features shown and described with respect to Figures 6A-6C in combination with any of the apparatus and methods described herein.

[0149] Reference is now made to Figures 6D, 6E, and 6F, which are schematic illustrations of an impeller 50 or a portion thereof, according to some applications of the present invention. As mentioned above, in some applications, the impeller 50 includes a suture 53. The suture 53 is wound around the helical elongate element 52 and is configured to promote bonding between a film of material (typically an elastomer such as polyurethane or silicone) and the helical elongate element (typically a shape memory alloy such as Nitinol).

[0150] Instead of or in addition to the sutures 53, in some applications, a coil 68 is wound (or disposed on) the helical elongate elements, as shown in FIG. 6D. For example, a tightly wound coil (e.g., a tightly wound Nitinol coil) can be wound (or disposed around) each of the helical elongate elements. The coil typically promotes bonding between the film of material and the helical elongate elements by increasing the surface area over which the material bonds at the interface between the material and the helical elongate elements. In some applications, the structure 59 is modularly formed (e.g., as described below with reference to FIG. 6F). In some such applications, a coil is disposed around each of the elongate elements 52 (e.g., by sliding the entire coil over the elongate elements in a single motion) prior to coupling the elongate elements to the proximal and distal bushings of the impeller.

[0151] Further, instead of or in addition to the sutures 53, in some applications, a sleeve 69 is placed around the helical elongate element, as shown in FIG. 6E. For example, such a sleeve may be made of a polymer such as polyester. The sleeve typically promotes bonding between the film of material and the helical elongate element by increasing the surface area of ​​the material to which the material bonds at the interface between the material and the helical elongate element. In some applications, the sleeve acts as an intermediary between the material from which the elongate element is made, typically having a relatively high stiffness (typically Nitinol), and the material from which the film 56 is made, typically an elastomer having a relatively low stiffness. The sleeve thereby improves the strength of the bond between the material and the helical elongate element when the material dries. In some applications, the sleeve 69 is applied to the structure 59. In some such applications, the sleeve is formed with a longitudinal slit to allow the sleeve to be placed around the helical elongate element 52. After placement around the helical elongate element 52, the slit is closed (e.g., by sewing or gluing the slit closed). In some applications, structure 59 is modularly formed (e.g., as described below with reference to FIG. 6F.) In some such applications, a sleeve is placed around elongated element 52 prior to coupling the elongated element to the proximal and distal bushings of the impeller.

[0152] Further, instead of or in addition to sutures 53, in some applications, elongated elements 52 are shaped to have a round (e.g., circular) cross-section, as shown in the right portion of FIG. 6F (showing a cross-section of an elongated element having a round cross-section). The left portion of FIG. 6F shows a cross-section of an elongated element 52 with a film 56 material bonded thereto, where the elongated element has a non-round cross-section (e.g., a square or rectangular cross-section). As shown, the material from which the film is made (e.g., silicone and / or polyurethane) may form a thin layer at the corners of the elongated element having a non-round cross-section. In contrast, when the elongated element has a round cross-section, as shown in the left portion of FIG. 6F, the material typically forms a layer with a substantially uniform thickness at the interface with the elongated element. Thus, in some applications, the elongated element has a round cross-section.

[0153] In some applications, the proximal and distal bushings 64, 58 and the elongated element 52 are cut from an alloy tube, for example, as described above. In such applications, after cutting the tube, the elongated element typically has non-rounded edges. Thus, in some applications, after cutting the tube, the edges of the elongated element are rounded, for example, by grinding, sandblasting, tumbling, etching, plasma, surface charging, and / or by adding rounded edges to the elongated element. Alternatively, the proximal and distal bushings and the elongated element can be modularly formed and then coupled to one another (e.g., by welding and / or crimping). In some such applications, the elongated element coupled to the proximal and distal bushings has a rounded cross section. As described above with reference to FIG. 6E, in some applications, a sleeve 69 is placed on the elongated element before coupling the elongated element to the proximal bushing and / or before coupling the elongated element to the distal bushing.

[0154] In some such applications, alternative or additional techniques are used to promote bonding between the film of material and the helical elongate element, for example, the helical elongate element can be treated using a surface treatment (grinding, sandblasting, tumbling, etching, plasma, surface charging, etc.) to roughen the outer surface of the helical elongate element.

[0155] According to the above description of Figures 6A to 6F, in some applications of the present invention, the impeller 50 is manufactured by forming a structure having first and second bushings 64, 58 at the proximal and distal ends. The first and second bushings are interconnected by at least one elongated element 52. The at least one elongated element is made to radially expand and form at least one helical elongated element by at least partially compressing the structure axially. An elastomeric material is bonded to the at least one helical elongated element such that the at least one helical elongated element together with the elastomeric material bonded thereto defines a blade of the impeller. Typically, this bonding is performed such that a layer of material is disposed around the radially outer edge of the at least one helical elongated element. The layer of material forms the active edge of the impeller blade (i.e., the edge at which the blood pumping function of the impeller is substantially inactive). More typically, the method includes performing a step of improving the bonding of the elastomeric material to the at least one helical elongated element such that it does not protrude beyond the active edge of the impeller vane. For example, a suture 53 may be disposed in a groove defined by the at least one helical elongated element such that it does not protrude beyond the radially outer edge of the helical elongated element. The suture is configured to improve the bonding of the elastomeric material to the at least one helical elongated element. Alternatively or additionally, a tightly wound coil 68 may be disposed around the at least one helical elongated element such that the elastomeric material forms a substantially smooth layer along the radially outer edge of the coil. The coil is configured to improve the bonding of the elastomeric material to the at least one helical elongated element. Further alternatively or additionally, a sleeve 69 may be disposed around the at least one helical elongated element such that the elastomeric material forms a substantially smooth layer along the radially outer edge of the sleeve. The sleeve is configured to improve the bonding of the elastomeric material to the at least one helical elongated element.In some applications, at least one of the helical elongate elements is provided with a round cross section so that the elastomeric material forms a layer having a substantially uniform thickness at the interface between the elastomeric material and the helical elongate element. As mentioned above, it is typically desirable for the gap G between the outer edge of the impeller vanes and the inner lining 39 (shown in FIG. 7) to be relatively small. Thus, it is desirable for there to be no protrusion from the effective edge of the impeller vanes, as such protrusion would occupy a portion of the gap between the outer edge of the impeller vanes (thus requiring a larger gap) without increasing the effectiveness of the blood pumping function of the impeller.

[0156] Reference is now made to Figures 6G and 6H, which are schematic illustrations of an elongated element 67 extending between each of the helical elongated elements 52 and the spring 54, according to some applications of the present invention. In some applications, each loop-shaped elongated element 67 extends between each of the helical elongated elements and the spring. Typically, the loop-shaped elongated elements are closed loops having a predefined length and being (substantially) inelastic. The length of the loop-shaped elongated elements is typically predefined to maintain the helical elongated elements (which define the outer edge of the impeller blades) within a given distance relative to the central axial spring, thereby maintaining a gap between the outer edge of the impeller blades and the inner surface of the frame 34 during rotation of the impeller, as described above. In some applications, the impeller is formed by wrapping a first end of the loop-shaped elongated element around each helical elongated element, as shown in the enlarged portions of Figures 6G and 6H. Thereafter, the spring 54 is inserted into the proximal and distal bushings 64, 58 and into the second end of the looped helical elongate element.

[0157] In some applications, as shown in Figures 6G and 6H, at the longitudinal center of the spring 54, the spring is shaped to define a tube 88 (i.e., no windings are present). Typically, the second end of the looped elongate element is wrapped around the tube at the longitudinal center of the spring. Typically, this reduces the risk of the looped elongate element tearing, as compared to when the second end of the looped elongate element is wrapped around the spring windings. In some applications (not shown), a groove is defined in the tube, and the second end of the looped elongate element is configured to be retained within the groove.

[0158] In some applications, the loop elongated element is wound around the body of the helical elongated element, as shown in the close-up of FIG. 6G. Close-ups A and B of FIG. 6G show two alternative ways of winding the loop elongated element around the body of the helical elongated element. In some applications, the loop elongated element is wound around the outer surface of the helical elongated element, as shown in close-up A. Alternatively, the helical elongated element defines a groove 48 on its outer surface, and the loop elongated element is wound around this groove 48 (so as to be embedded within the groove), as shown in close-up B. By embedding the loop elongated element in the groove, the loop elongated element does not typically expand the outer shape of the impeller, which is defined by the outer surface of the helical elongated element.

[0159] In some applications, as shown in the close-up of FIG. 6H, the helical elongated element is shaped to define two holes 91 located very close to each other through which the loop-shaped elongated element can be wound. Close-ups A and B of FIG. 6H show two alternative ways of winding the loop-shaped elongated element through the holes 91. In some applications, as shown in close-up A, the loop-shaped elongated element is wound through the holes 91 on the outer surface of the helical elongated element. Alternatively, as shown in close-up B, the helical elongated element defines a groove 48 on the outer surface and the loop-shaped elongated element is wound through the holes 91 into the groove 48 (so as to be embedded within the groove). By embedding the loop-shaped elongated element within the groove, the loop-shaped elongated element does not typically expand the outer shape of the impeller, which is defined by the outer surface of the helical elongated element.

[0160] Reference is now made to Figures 8A and 8B, which are schematic illustrations of the impeller 50 and frame 34 of the blood pump catheter 20, 70, or 90 in a radially unconstrained and radially constrained state, respectively, according to some applications of the present invention. The impeller and frame are typically disposed in a radially constrained state during transcatheter insertion of the impeller and frame into the subject's body, and in a radially unconstrained configuration during operation of the blood pump catheter. As noted above, typically, a covering material 36 extends from the frame 34. However, for purposes of illustration, the frame and impeller are shown without the covering material 36 in Figures 8A-8B. As shown in Figure 8B, the frame and impeller are typically maintained in a radially constrained configuration by a delivery catheter 143.

[0161] Also see FIG. 8C, which illustrates a typical bearing assembly used in a prior art axial impeller-based blood pump. FIG. 8C is shown for the purpose of serving as a reference for some of the applications of the invention described herein. As shown in FIG. 8C, the bearing assembly typically includes a radial bearing (shown as oval 200) and a thrust bearing (shown as circle 202). The radial bearing is configured to reduce radial motion of the impeller by maintaining the axis of the impeller at a given radial position. In response to the impeller pumping blood in a first direction, the forces acting on the impeller typically move the impeller in a direction opposite to the first direction. The purpose of the thrust bearing is to oppose such impeller motion and maintain the axial position of the impeller. In the example shown in FIG. 8C, in response to the impeller pumping blood in the direction of arrow 204, the impeller is pushed in the direction of arrow 206, and the thrust bearing opposes this motion. Typically, bearings experience significant amounts of heating and wear due to the frictional forces applied. Thrust bearings are typically subject to significant heating and wear because the frictional forces applied to thrust bearings are typically spread over a smaller contact area of ​​opposing surfaces than radial bearings.

[0162] As mentioned above, typically the axial shaft 92 passes through the axis of the impeller 50 through the impeller bore 62. Typically the impeller proximal bushing 64 is coupled to the shaft via a coupling element 65 such that the axial position of the proximal bushing relative to the shaft is fixed, and the impeller distal bushing 58 is slidable relative to the shaft. The axial shaft itself is radially stabilized by proximal radial bearing 116 and distal radial bearing 118.

[0163] Typically, the coupling portion 30 of the frame 34 is coupled to the proximal radial bearing 116, for example, by a snap-fit ​​connection and / or welding. Typically, at the distal end of the frame 34, the distal strut joint 33 is located in a groove defined by the outer surface of the distal radial bearing 118, which groove is shaped to match the shape of the distal strut portion. As shown, the proximal end of the distal end element 108 typically holds the distal strut portion in a closed configuration around the outside of the distal radial bearing 118. In some applications, the device includes a distal extension 121 extending distally from the distal radial bearing. Typically, the extension is configured to reinforce the area of ​​the distal end element where the distal end of the shaft 92 enters.

[0164] As discussed above, the axial shaft 92 is radially stabilized by the proximal radial bearing 116 and the distal radial bearing 118. The axial shaft also extends through the bore 62 defined by the impeller, thereby radially stabilizing the impeller against the inner surface of the frame 34, such that a relatively small gap (e.g., as discussed above) between the outer edges of the impeller blades and the inner surface or inner lining 39 of the frame 34 is maintained during rotation of the impeller, as discussed above. In some applications, the axial shaft 92 is made of stainless steel, and the proximal bearing 116 and / or the distal bearing 118 are made of hardened steel. Typically, when the impeller and frame are compressed (i.e., radially constrained) for insertion into a subject's body, the distal bushing 58 of the impeller is configured to slide distally along the axial shaft such that the impeller lengthens axially, while the proximal bushing maintains an axially fixed position relative to the axial shaft. More generally, the impeller changes from a radially constrained configuration to a radially unconstrained configuration, and vice versa, by the distal bushing sliding on the axial shaft while the proximal bushing maintains an axially fixed position relative to the axial shaft.

[0165] Typically, the impeller itself is not directly disposed in a radial or thrust bearing, and the bearings 116 and 118 act as radial bearings for the axial shaft. Typically, the blood pump catheter does not include a thrust bearing configured to be disposed in the subject's body and configured to counter the thrust generated by the rotation of the impeller. In some applications, one or more thrust bearings are disposed outside the subject's body (e.g., in the motor unit), and the counteraction to the thrust generated by the rotation of the impeller is provided only by the one or more thrust bearings disposed outside the subject's body. In some applications, mathematical and / or magnetic elements are configured to maintain the impeller within a given axial position range. For example, a magnet disposed at the proximal end of the drive cable may be configured to maintain the impeller within a given axial position range.

[0166] In some alternative applications of the present invention, a thrust bearing is used to maintain the axial position of the impeller, and the thrust bearing is located in a portion of the blood pump catheter proximal to the impeller, so as not to contact the subject's blood. For example, the thrust bearing can be located in an outer tube in which the drive shaft of the impeller is located. Alternatively or additionally, the thrust bearing may be located outside the subject's body. In some such applications, since the thrust bearing is located outside the subject's body, the size of the thrust bearing is not constrained by the need to deploy in a small anatomical site. Thus, in such cases, the contact area between the two opposing surfaces of the thrust bearing is typically greater than 20 square millimeters. In some applications (not shown), the thrust bearing is located distal to the impeller, in contact with the subject's blood, so that the thrust bearing is cooled by the subject's blood.

[0167] Typically, the operations described herein performed by a computer processor transform the physical state of memory, which is an actual physical article in communication with the computer processor, to have different magnetic poles, charges, etc., depending on the memory technology being used. Computer processor 10 is typically a hardware device that is programmed with computer program instructions to create a special-purpose computer. For example, when programmed to execute the techniques described herein, computer processor 10 typically acts as a special-purpose blood pump computer processor.

[0168] The scope of the present invention includes combining any of the devices and methods described herein with any of the devices and methods described in one or more of the following applications, all of which are incorporated herein by reference:

[0169] U.S. Patent Application Publication No. 16 / 750,354 to Tuval, filed January 23, 2020, entitled “Distal tip element for a ventricular assist device.”

[0170] U.S. Patent Application Publication No. 2019 / 0209758 to Tuval, which is a continuation of International Application No. PCT / IB2019 / 050186 to Tuval entitled "Ventricular assist device," filed on January 10, 2019 (published as WO19 / 138350), which claims priority from: U.S. Provisional Patent Application No. 62 / 615,538 to Sohn, filed January 10, 2018, entitled “Ventricular assist device.” U.S. Provisional Patent Application No. 62 / 665,718 to Sohn, filed May 2, 2018, entitled “Ventricular assist device.” U.S. Provisional Patent Application No. 62 / 681,868 to Tuval, entitled "Ventricular assist device," filed June 7, 2018; and U.S. Provisional Patent Application No. 62 / 727,605 to Tuval, filed September 6, 2018, entitled “Ventricular assist device.”

[0171] U.S. Patent Application Publication No. 2019 / 0269840 to Tuval, which is the U.S. national stage of International Patent Application PCT / IL2017 / 051273 to Tuval entitled "Blood pumps," filed November 21, 2017 (published as WO18 / 096531), which claims priority from U.S. Provisional Patent Application No. 62 / 425,814 to Tuval, filed November 23, 2016.

[0172] U.S. Patent Application Publication No. 2019 / 0175806 to Tuval, which is a continuation of International Application No. PCT / IL2017 / 051158 to Tuval entitled "Ventricular assist device," filed on October 23, 2017 (published as WO18 / 078615), which claims priority from U.S. Patent Application Publication No. 62 / 412,631 to Tuval, filed on October 25, 2016, and U.S. Patent Application Publication No. 62 / 543,540 to Tuval, filed on August 10, 2017.

[0173] U.S. Patent Application Publication No. 2019 / 0239998 to Tuval, which is the U.S. national stage of International Patent Application PCT / IL2017 / 051092 to Tuval entitled "Blood vessel tube," filed on September 28, 2017 (published as WO18 / 061002), which claims priority from U.S. Provisional Patent Application No. 62 / 401,403 to Tuval, filed on September 29, 2016.

[0174] U.S. Patent Application Publication No. 2018 / 0169313 to Schwammenthal, which is the U.S. national stage of International Patent Application No. PCT / IL2016 / 050525 to Schwammenthal, entitled "Blood pump," filed May 18, 2016 (published as WO16 / 185473), which claims priority from U.S. Provisional Patent Application No. 62 / 162,881 to Schwammenthal, entitled "Blood pump," filed May 18, 2015.

[0175] U.S. Patent Application Publication No. 2017 / 0100527 to Schwammenthal, which is the U.S. national stage of International Patent Application No. PCT / IL2015 / 050532 to Schwammenthal entitled "Blood pump," filed May 19, 2015 (published as WO15 / 177793), which claims priority from U.S. Provisional Patent Application No. 62 / 000,192 to Schwammenthal entitled "Blood pump," filed May 19, 2014.

[0176] No. 10,039,874 to Schwammenthal, which is a U.S. national stage application of International Patent Application No. PCT / IL2014 / 050289 to Schwammenthal entitled "Renal pump," filed March 13, 2014 (published as WO14 / 141284), which claims priority from (a) U.S. Provisional Patent Application No. 61 / 779,803 to Schwammenthal entitled "Renal pump," filed March 13, 2013, and (b) U.S. Patent No. 10,039,874 to Schwammenthal, which is a U.S. national stage application of International Patent Application No. PCT / IL2014 / 050289 to Schwammenthal entitled "Renal pump," filed March 13, 2014 (published as WO14 / 141284), which claims priority from U.S. Provisional Patent Application No. 61 / 914,475 to Schwammenthal entitled "Renal pump," filed December 11, 2013.

[0177] U.S. Patent No. 9,764,113 to Tuval entitled "Curved catheter," issued on September 19, 2017, which claims priority from U.S. Provisional Patent Application No. 61 / 914,470 to Tuval entitled "Curved catheter," filed on December 11, 2013; and

[0178] U.S. Patent No. 9,597,205 to Tuval, which is a U.S. national phase of International Patent Application No. PCT / IL2013 / 050495 to Tuval, entitled "Prosthetic renal valve," filed on June 6, 2013 (published as WO13 / 183060), which claims priority from U.S. Provisional Patent Application No. 61 / 656,244 to Tuval, entitled "Prosthetic renal valve," filed on June 6, 2012.

[0179] Those skilled in the art will recognize that the present invention is not limited to what has been particularly shown and described above, and the scope of the present invention includes both combinations and subcombinations of the various features described above, as well as variations and modifications thereof that would occur to one skilled in the art upon reading the foregoing description, and that are not present in the prior art.

Claims

1. 1. An apparatus for use with the venous system of a subject including one or more tributary vessels draining into a vein at a junction of the vein and one or more tributary vessels, comprising:

1. A blood pump catheter comprising: a material defining a blood exit aperture configured to be placed at a downstream location downstream of the junction and to at least partially occlude blood flow through the vein at the downstream location; a blood pump configured to pump blood from a region of the vein adjacent the junction through the blood outlet opening defined in the material; a blood pump catheter including: (a) a pathway inlet opening disposed at an upstream position upstream of the junction; and (b) a pathway outlet opening opening downstream of the material; The blood flow pathway is configured to direct upstream venous blood flow from the upstream location downstream of the material without pumping by the pump.

2. 2. The apparatus of claim 1, wherein the blood pump comprises an elongated blood pump tube defining a blood inlet area disposed within an upstream portion of the elongated blood pump tube, a blood outlet area disposed within a downstream portion of the elongated blood pump tube, and an impeller configured to pump blood into the blood inlet area and further out of the blood outlet area through the elongated blood pump tube.

3. 10. The apparatus of claim 1, wherein the blood pump comprises an impeller disposed within a frame, the impeller configured to pump blood by rotating within the frame.

4. The blood pump catheter is configured for use with one or more lymphatic vessels draining into a vein, the blood pump catheter being configured to be placed within the vein, such that: the material is placed at a downstream location downstream of a junction between the vein and the one or more lymphatic vessels and adapted to at least partially occlude blood flow through the vein at the downstream location; the blood pump is configured to pump blood from a region of the vein adjacent the junction of the vein and the one or more lymphatic vessels through the blood outlet opening defined in the material; the blood flow pathway passes between (a) the pathway inlet opening disposed at an upstream location upstream of the region of the vein adjacent the junction of the vein with the one or more lymphatic vessels, and (b) the pathway outlet opening opening to the downstream side of the material; The apparatus of claim 1 , wherein the blood flow pathway is configured to direct upstream venous blood flow from the upstream location to the downstream side of the material without pumping the blood flow by the pump.

5. The blood pump catheter is configured to be placed in a vena cava of the subject, the material is placed at a downstream location downstream of a junction of the vena cava with one or more renal veins of the subject and adapted to at least partially occlude blood flow through the vena cava at the downstream location; the blood pump is configured to pump blood from a region of the vena cava adjacent the junction of the vena cava with the one or more renal veins through the blood outlet opening defined in the material; the blood flow pathway passes between (a) the pathway inlet opening disposed at an upstream location upstream of a junction of the vena cava and the one or more renal veins, and (b) the pathway outlet opening opening to the downstream side of the material; 5. The device of claim 1, wherein the blood flow pathway is configured to direct blood flow from the infrarenal vena cava blood flow downstream of the material without pumping the infrarenal vena cava blood flow by the pump.

6. 6. The apparatus of claim 5, further comprising a percutaneous left ventricular assist device configured to assist left ventricular function in the subject.

7. 6. The apparatus of claim 5, wherein the blood pump comprises an elongated blood pump tube defining a blood inlet area disposed within an upstream portion of the elongated blood pump tube, a blood outlet area disposed within a downstream portion of the elongated blood pump tube, and an impeller configured to pump blood into the blood inlet area and further out of the blood outlet area through the elongated blood pump tube.

8. 8. The apparatus of claim 7, wherein the elongated blood pump tube is configured to be positioned such that the blood outlet area is positioned within a pulmonary artery of the subject and configured to pump blood through the elongated blood tube and into the pulmonary artery of the subject.

9. 8. The apparatus of claim 7, further comprising an elongated tube extending downstream from the material and defining an adrenal blood inlet opening configured to be positioned within the subject's adrenal vena cava, the blood inlet area of ​​the elongated blood pump tube configured to be positioned downstream of the adrenal blood inlet opening, and the elongated blood pump tube configured to pump blood from the adrenal vena cava blood flow into a pulmonary artery of the subject.

10. 6. The apparatus of claim 5, further comprising an elongated tube configured to extend into a pulmonary artery of the subject, the blood pump configured to pump blood through the elongated tube and into the pulmonary artery of the subject.

11. 11. The apparatus of claim 10, wherein the elongated tube defines an adrenal blood inlet opening configured to be positioned within the adrenal vena cava of the subject, and the blood pump is configured to be positioned downstream of the adrenal blood inlet opening and configured to pump blood from the adrenal vena cava blood flow into a pulmonary artery of the subject.

12. 6. The device of claim 5, wherein a diameter of one or more portions of the blood flow pathway is adjustable such that flow from the inferior renal vena cava blood flow to the subject's right atrium is adjustable.

13. 13. The apparatus of claim 12, further comprising a blood pressure sensor configured to detect a blood pressure of the subject; and a computer processor configured to receive a blood pressure of the subject and automatically adjust the diameter of the one or more portions of the blood flow pathway in response to the detected blood pressure.

14. The device of claim 12 , wherein the diameter of the one or more portions of the blood flow pathway is configured to adjust in response to an input.

15. 5. The device of claim 1, wherein the blood flow pathway comprises a funnel having a wide end and a narrow end, and one or more tubes, the wide end of the funnel defining the pathway entrance opening and the narrow end of the funnel extending into the one or more tubes.

16. The apparatus of claim 15 , wherein the funnel and the one or more tubes comprise a single continuous blood flow pathway.

17. 5. The device of claim 1, wherein a diameter of one or more portions of the blood flow pathway is adjustable such that flow through the blood flow pathway is adjustable.

18. 20. The apparatus of claim 17, further comprising a blood pressure sensor configured to detect a blood pressure of the subject; and a computer processor configured to receive a blood pressure of the subject and automatically adjust the diameter of the one or more portions of the blood flow pathway in response to the detected blood pressure.

19. 20. The device of claim 17, wherein the diameter of the one or more portions of the blood flow pathway is configured to adjust in response to an input.

20. 1. A blood pump catheter comprising: a material disposed on the blood pump catheter and defining a blood exit aperture configured to at least partially occlude blood flow through a vein; a blood pump configured to pump blood through the blood outlet opening defined in the material; a blood pump catheter including: (a) a pathway inlet opening disposed at a position proximal to the material; and (b) a pathway outlet opening opening distal to the material; The blood flow pathway is configured to direct blood flow from the pathway inlet opening to the pathway outlet opening without pumping by the pump.

21. 1. An apparatus for use with the arterial system of a subject, the arterial system including a main artery and one or more branch arteries branching from the main artery at a junction of the main artery with one or more branch arteries, the apparatus comprising:

1. A blood pump catheter comprising: a material defining a blood inlet opening configured to be placed at a downstream location downstream of the junction of the main artery and the branch artery and to at least partially occlude blood flow through the main artery at the downstream location; a blood pump configured to pump blood from the main artery towards the branch artery through the blood inlet opening; a funnel configured to be positioned at an upstream location upstream of a junction of the main artery and the branch artery; a blood pump catheter including: (a) a pathway inlet opening disposed at an upstream location upstream of a junction between the main artery and the branch artery; and (b) a pathway outlet opening opening downstream of the material; The blood flow pathway is configured to direct upstream major arterial blood flow from the upstream location downstream of the material without pumping by a pump.

22. 1. An apparatus for use with the descending aorta of a subject, comprising:

1. A blood pump catheter comprising: a material defining a blood exit aperture configured to be placed within the descending aorta and to separate the aorta into an upstream section and a downstream section by at least partially occluding blood flow through the aorta; a blood pump configured to pump blood flowing through the descending aorta downstream through the blood outlet opening; 1. An apparatus comprising a blood pump catheter comprising:

23. 1. A blood pump catheter configured to be placed in a blood vessel of a subject, comprising: an impeller configured to pump blood by rotation; an impeller housing configured to be disposed around the impeller; a blood pump support frame configured to be positioned upstream of the impeller housing and to at least partially align a longitudinal axis of the impeller housing with a local longitudinal axis of the blood vessel by contacting an inner wall of the blood vessel; a blood pump catheter comprising: a material defining a blood outlet opening extending from the impeller housing to the blood pump support frame and configured to contact the blood vessel wall and occlude the blood vessel in an area of ​​the blood vessel surrounding the impeller; and the impeller configured to pump blood through the blood outlet opening.

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