Abstract: Apparatus and methods are described including a blood pump configured to be placed inside a subject's body. An impeller includes proximal and distal bushings and an axial shaft configured to pass through the proximal and distal bushings. A first one of the proximal and distal bushings is axially-fixed to the axial shaft, and a second one of the proximal and distal bushings is not axially-fixed to the axial shaft. The impeller defines a radially-constrained configuration in which the impeller is introduced into the subject's body and a non-radially-constrained configuration in which the impeller is configured to pump blood within the subject's body. The impeller changes from its radially-constrained configuration to its non-radially constrained configuration by the second bushing sliding over the axial shaft. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump configured to be placed inside a body of subject. The blood pump includes an impeller that defines a lumen therethrough, and an axial shaft that passes through the lumen. The impeller is configured to assume a radially-constrained configuration by becoming axially elongated. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an impeller configured to pump blood through a subject's body, and a frame disposed around the impeller. In a radially-non-constrained configuration of the frame, the frame defines a proximal conical portion and a cylindrical portion disposed distally to the proximal conical portion. The blood pump is configured such that such that, during at least some of the operation of the blood pump, at least a portion of the impeller is disposed within the proximal conical portion of the frame. Other applications are also described.

Abstract: Apparatus and methods are described including an impeller that includes an impeller frame that comprises proximal and distal end portions and a plurality of blades. Each of the impeller blades includes a curved elongate element and at least one radial element extending radially from the curved elongate element toward a longitudinal axis of the impeller frame. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an impeller, and a frame disposed around the impeller. An axial shaft extends from a proximal end of the frame to a distal end of the frame. The impeller is coupled to the axial shaft. A radial bearing is configured to radially stabilize the axial shaft and aa bearing housing houses the radial bearing. A layer of elastomeric material is disposed between the radial bearing and the bearing housing. Other applications are also described.

Abstract: Apparatus and methods are described including a solid axial shaft having a shaft diameter that is less than 0.8 mm, an impeller configured for insertion into a left ventricle of a heart of a subject and coupled to the axial shaft, and a hollow drive cable coupled, at a distal end of the drive cable, to the axial shaft, and configured to rotate so as to rotate the axial shaft, thereby causing the impeller to pump blood of the subject from the left ventricle. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an axial shaft configured for insertion into, and rotation within, a subject's body. The blood pump also includes an impeller coupled to the axial shaft such that, as the axial shaft rotates, the impeller pumps blood of the subject. Proximal and distal radial bearings surround the axial shaft and are configured to radially stabilize the axial shaft while the axial shaft rotates. Proximal and distal sleeves, which are less flexible than the axial shaft, are disposed around the axial shaft, such that the proximal and distal sleeves contact the proximal and distal radial bearings, respectively, as the axial shaft rotates. A ratio between a length of the axial shaft and a combined length of the proximal sleeve and distal sleeve is between 2:1 and 6:1. Other applications are also described.

Abstract: Apparatus and methods are described including a left-ventricular assist device that includes a frame that includes proximal and distal frame portions that include struts that define cells, and a central frame portion that includes helical struts. An impeller is disposed inside the frame, the impeller being configured to rotate such as to pump blood from a left ventricle of a subject to an aorta of the subject. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an axial shaft configured for insertion into, and rotation within, a subject's body. The blood pump also includes an impeller, which includes a proximal bushing disposed over the axial shaft, a distal bushing disposed over the axial shaft distally from the proximal bushing, and one or more blades. Each of the blades includes a single inner helical elongate element, a single outer helical elongate element, and a film of material extending between the inner helical elongate element and the outer helical elongate element. The blades are proximally coupled to the proximal bushing and distally coupled to the distal bushing such that, as the axial shaft rotates, the blades rotate, thereby pumping blood of the subject. Other applications are also described.

Abstract: Apparatus and methods are described including a ventricular assist device that includes a tube configured to traverse a subject's aortic valve. The tube defines a generally-cylindrical central portion, and a proximal conical portion that narrows from a proximal end of the central portion to a proximal end of the tube. The tube defines one or more blood inlet openings in a vicinity of a distal end of the tube, and one or more blood outlet openings that extend axially from the central portion of the tube at least partially into the proximal conical portion of the tube. A blood pump pumps blood into the tube from the subject's left ventricle through the one or more blood inlet openings, and from the tube into the aorta through the one or more blood outlet openings. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes a pump-outlet tube shaped to define one or more blood-outlet openings and configured for insertion into a heart of a subject. An impeller is disposed within a distal portion of the pump-outlet tube and is configured to pump blood of the subject proximally through the pump-outlet tube, such that the blood exits the pump-outlet tube through the blood-outlet openings. A delivery tube extends, from outside a body of the subject, through the pump-outlet tube to the distal portion. A drive cable passes through the delivery tube and is configured to rotate the impeller. A proximal portion of the pump-outlet tube includes multiple strips adhered to the delivery tube. Other embodiments are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an impeller configured to pump blood through a subject's body, and a frame disposed around the impeller. In a radially-non-constrained configuration of the frame, the frame defines a proximal conical portion and a cylindrical portion disposed distally to the proximal conical portion. During operation of the blood pump, the impeller moves with respect to the frame, and a range of movement of the impeller is such that at least a first portion of the impeller is disposed within the proximal conical portion of the frame during at least some of the operation of the blood pump, and at least a second portion of the impeller is disposed within the cylindrical portion of the frame during at least some of the operation of the blood pump. Other applications are also described.

Abstract: Apparatus and methods are described including a left ventricular assist device that includes an axial flow impeller configured to be disposed within a subject's left ventricle and to pump blood axially from the subject's left ventricle to the subject's aorta. A frame is disposed around the impeller, the frame being shaped such that, in a non-radially-constrained configuration of the frame, the frame defines a central cylindrical portion, and a distal conical portion. The frame is at least partially covered with one or more tube portions, the tube portions defining one or more blood-inlet openings that are configured to allow blood to flow from the subject's left ventricle into the tube portions, wherein at least some of the one or more blood-inlet openings are at least partially disposed over the distal conical portion of the frame. Other applications are also described.

Abstract: Apparatus and methods are described including reducing cardiac preload of a subject by partially occluding a vena cava of the subject at an infra-renal location. One or more physiological parameters of the subject are monitored, the one or more physiological parameters including lower body venous pressure, central venous pressure, central venous blood flow, renal venous pressure, cardiac diameter, cardiac volume, arterial pressure, and/or arterial blood flow. An extent to which the vena cava is occluded at the infra-renal location is modulated, responsively to the one or more physiological parameters. Other applications are also described.

Abstract: Apparatus and methods are described including a tube configured to traverse an aortic valve of a subject. A frame is disposed within at least a portion of the tube. An impeller rotates such as to pump blood from the subject's left ventricle to the subject's aorta. The impeller is disposed inside the tube such that, when the impeller and the tube are deployed inside the subject, and prior to rotation of the impeller, a radial gap between an outer edge of the impeller and an inner surface of the tube is less than 1 mm. The impeller is radially stabilized such that, during rotation of the impeller, a radial gap between the outer edge of the impeller and the inner surface of the tube is maintained. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an axial shaft configured for insertion into, and rotation within, a body of a subject. An impeller is coupled to the axial shaft such that, as the axial shaft rotates, the impeller pumps blood of the subject. A thrust bearing includes a proximally-facing ceramic surface disposed distally from the axial shaft so as to inhibit distal movement of the axial shaft beyond the thrust bearing, and a distally-facing ceramic cover that covers a distal end of the axial shaft, such that the ceramic cover contacts the ceramic surface as the axial shaft rotates. Other applications are also described.

Abstract: Apparatus and methods are described including a left ventricular assist device that includes an impeller configured to be placed inside a left ventricle of a subject and to pump blood from the left ventricle to an aorta of the subject, by rotating. A frame is disposed around the impeller. A tube is configured to traverse an aortic valve of the subject, such that a proximal portion of the tube is disposed within the subject's aorta and a distal portion of the tube is disposed within the subject's left ventricle. The distal portion of the tube extends to a distal end of the frame and defines one or more lateral blood inlet openings that are configured to allow blood to flow from the subject's left ventricle into the tube. Other applications are also described.

Abstract: Apparatus and methods are described including manufacturing an impeller by forming a structure having first and second bushings at proximal and distal ends of the structure, the first and second bushings being connected to one another by at least one elongate element. The elongate element is caused to radially expand and form at least one helical elongate element, at least partially by axially compressing the structure. The helical elongate element is coated with a coupling agent configured to enhance bonding between the helical elongate element and an elastomeric layer. The coated helical elongate element is coated with the elastomeric layer. Subsequently, an elastomeric film is coupled to the helical elongate element, such that the helical elongate element with the elastomeric film coupled thereto defines a blade of the impeller. Other applications are also described.

Abstract: Apparatus and methods are described including a left-ventricular assist device that includes a pump-outlet tube shaped to define one or more blood-outlet openings and configured for insertion, through an aorta of a subject, into a left ventricle of a heart of the subject such that the pump-outlet tube traverses an aortic valve of the subject with the blood-outlet openings being disposed within the aorta. A blood pump is disposed at least partly within a distal portion of the pump-outlet tube and is configured to pump blood of the subject proximally through the pump-outlet tube. A proximal end of the pump-outlet tube is folded inwardly so as to define one or more surfaces configured to direct the blood through the blood-outlet openings by virtue of being oblique with respect to a longitudinal axis of the pump-outlet tube. Other applications are also described.

Abstract: Apparatus and methods are described including a tube configured to traverse an aortic valve of a subject. A frame is disposed within at least a portion of the tube. An impeller rotates such as to pump blood from the subject's left ventricle to the subject's aorta. The impeller is disposed inside the tube such that, when the impeller and the tube are deployed inside the subject, and prior to rotation of the impeller, a gap between an outer edge of the impeller and an inner surface of the tube is less than 1 mm. A rigid stabilizing element stabilizes the impeller with respect to the tube, such that during rotation of the impeller, a gap between the outer edge of the impeller and the inner surface of the tube is maintained. Other applications are also described.