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 an impeller, and a motor configured to drive the impeller to pump blood by rotating the impeller. The impeller is configured to undergo axial motion, in response to changes in a pressure against which the impeller is pumping. A sensor detects the axial motion of the impeller, and generates a sensor signal in response thereto. A computer processor receives the sensor signal and generates an output in response thereto. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump catheter that includes an axial shaft, and an impeller disposed on the axial shaft. A motor drives the impeller to pump blood, by rotating the impeller. A drive cable extends from the motor to the axial shaft, the drive cable being configured to impart rotational motion from the motor to the impeller by rotating. A distal tip portion is disposed at a distal end of the blood pump catheter. The drive cable, the axial shaft, and the distal tip portion define a continuous lumen therethrough from outside the subject's body to the distal end of the blood pump catheter. The continuous lumen facilitates insertion of the blood pump catheter into the subject's body over a guidewire, and, subsequently, provides a channel through which the purging fluid flows. 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 including an impeller that includes proximal and distal bushings, and a frame disposed around the impeller, the frame including proximal and distal bearings. An axial shaft passes through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller. 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 distal bushing sliding over the axial shaft. Other applications are also described.

Abstract: Apparatus and methods are described, including a blood pump that includes a catheter, a proximal impeller disposed on the catheter inside a proximal impeller housing, and which is configured to pump blood by rotating inside the proximal impeller housing. A distal impeller is disposed on the catheter inside a distal impeller housing, distally to the proximal impeller, and the distal impeller is configured to pump blood by rotating inside the distal impeller housing. A tubular element is disposed between the proximal impeller housing and the distal impeller housing, the tubular element being configured to have a tubular configuration during rotation of the proximal and distal impellers. Other applications are also described.

Abstract: Apparatus and methods are described including a left-ventricular assist device that includes a tube configured to traverse a subject's aortic valve, with a distal portion of the tube disposed within the subject's left ventricle. A frame is disposed within the distal portion of the tube. A pump disposed within the frame pumps blood through the tube. A distal-tip element defines a straight proximal portion that defines a longitudinal axis, and a curved distal portion that is shaped such as to curve in a first direction with respect to the longitudinal axis before passing through an inflection point and curving in a second direction with respect to the longitudinal axis, such that the curved distal portion defines a bulge on one side of the longitudinal axis. Other applications are also described.

Abstract: Apparatus and methods are described including coupling a rigid tube to a drive cable that comprises a plurality of coiled wires, by placing ends of the drive cable and the rigid tube at a given location within a butt-welding overtube. The ends of the drive cable and the rigid tube are visible when they are disposed at the given location within the butt-welding overtube, via a window defined by the butt-welding overtube. The placement of the drive cable within the butt-welding overtube is such that a helical groove within a portion of the butt-welding overtube is disposed over the drive cable. Welding rings are formed around the butt-welding overtube. Other applications are also described.

Abstract: Apparatus and methods are described including a left-ventricular assist device that includes a tube configured to traverse a subject's aortic valve, with a distal portion of the tube within the subject's left ventricle. A frame disposed within the distal portion of the tube defines cells, and a width of each of the cells within a cylindrical portion of the frame is less than 2 mm. An inner lining lines at least some of the cylindrical portion of the frame. An impeller is disposed inside the frame such that a gap between an outer edge of the impeller and the inner lining is less than 1 mm. The impeller is stabilized with respect to the frame, such that, during rotation of the impeller, the gap between the outer edge of the impeller and the inner lining is maintained and is substantially constant. 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. The frame defines struts having a structure that is such that, as the frame transitions from a proximal end of the frame toward a center of the frame, the struts pass through junctions, at which the two struts branch from a single strut, in a Y-shape. The structure of the struts of the frame is configured such that, in response to a distal end of a delivery catheter and the frame being moved into overlapping positions with respect to each other, the frame assumes a radially-constrained configuration by becoming axially elongated, and the frame causes the impeller to assume a radially-constrained configuration by becoming axially elongated. 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 that are connected to one another by at least one elongate element. The elongate element is made to radially expand and form a helical elongate element. An elastomeric material is coupled to the helical elongate element, such that the helical elongate element with the elastomeric material coupled thereto defines a blade of the impeller. The coupling is performed such that a layer of the material disposed around a radially outer edge of the helical elongate element forms the effective edge of the impeller blade. A step is performed to enhance bonding of the elastomeric material to the helical elongate element in a manner that does not cause a protrusion from the effective edge of the impeller blade. Other applications are also described.

Abstract: Apparatus and methods are described including manufacturing a housing for an impeller of a blood pump by placing an inner lining around a mandrel, placing a cylindrical portion of a frame around the inner lining, and placing a distal portion of an elongate tube around a portion of the frame. While the distal portion of the elongate tube is disposed around the portion of the frame, the inner lining, the frame, and the distal portion of the elongate tube are heated, via the mandrel, and pressure is applied from outside the distal portion of the elongate tube, such as to cause the distal portion of the elongate tube to conform with a structure of the struts of the frame, and to cause the inner lining and the distal portion of the elongate tube to become coupled to the frame. Other applications are also described.

Abstract: Apparatus and methods are described including a tube (20) that defines a flared downstream portion (30) that diverges toward a downstream end (32) of the tube, and a flared upstream portion (26) that diverges toward an upstream end (28) of the tube, such that a central portion (34) of the tube is narrower than at the ends of the tube. The tube defines a plurality of lateral openings (36). A support frame (24) supports the tube within a subject's vena cava, such that the downstream portion is sealed with respect to the wall of the vena cava downstream of junctions of the vena cava with all of the subject's renal veins, and the upstream portion is sealed with respect to the inner wall of the vena cava upstream of junctions of the vena cava with all of the subject's renal veins. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an impeller that has proximal and distal bushings, and is configured to pump blood through a subject's body. A frame, which includes proximal and distal bearings, is disposed around the impeller. An axial shaft passes through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller. The axial shaft is coupled to at least one of the proximal and distal bushings of the impeller, such that the at least one bushing is held in an axially-fixed position with respect to the axial shaft, and is not held in an axially-fixed position with respect to the proximal and distal bearings. 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 including an impeller that includes proximal and distal bushings, and a frame disposed around the impeller, the frame including proximal and distal bearings. An axial shaft passes through the proximal and distal bearings of the frame and the proximal and distal bushings of the impeller. 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 distal bushing sliding over the axial shaft.

Abstract: Apparatus and methods are described including placing an impeller of a ventricular assist device inside a left ventricle of a subject, with a frame disposed around the impeller. The impeller is driven to pump blood from the left ventricle to an aorta of the subject, by rotating the impeller. The impeller is placed inside the left ventricle such that the impeller is allowed to undergo axial motion with respect to the frame, in response to cyclical changes in a pressure difference between the left ventricle and the aorta. Other applications are also described.

Abstract: Apparatus and methods are described including placing, into a subject's body, a blood-pump tube, with a blood pump disposed within the blood-pump tube. At least one blood-pressure-measurement tube, which defines an opening at a distal end thereof, extends to at least an outer surface of the blood-pump tube, such that the opening at the distal end of the blood-pressure-measurement tube is in direct fluid communication with a bloodstream of the subject outside the blood-pump tube. Blood is pumped through the blood-pump tube, using the blood pump. Pressure of the bloodstream of the subject outside the blood-pump tube is measured by measuring pressure of blood within the blood-pressure-measurement tube. Other applications are also described.

Abstract: Apparatus and methods are described including placing a blood pump into a subject's body, the blood pump including an axial shaft, an impeller disposed on the axial shaft, and a drive cable extending from outside the subject's body to the axial shaft. The impeller is driven to pump blood from a distal end of the impeller to a proximal end of the impeller by imparting rotational motion to the impeller via the drive cable, in a given direction of rotation. At least a portion of the drive cable includes a plurality of wires disposed in a coiled configuration that is such that, in response to the drive cable rotating in the given direction of rotation, the plurality of wires disposed in the coiled configuration at least partially unwind, such that the portion of the drive cable shortens axially. Other applications are also described.

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

Abstract: Apparatus and methods are described including a tube configured to traverse a subject's aortic valve. A frame is disposed within a portion of the tube, and a plurality of winged projections are coupled to the frame. An impeller is disposed inside the tube, the impeller including proximal and distal bushings, a helical elongate element, and a spring disposed inside of the helical elongate element, the spring defining a lumen therethrough. A film of material is supported between the helical elongate element and the spring. A rigid shaft extends from the proximal bushing to the distal bushing via the lumen defined by the spring. The impeller is rotated, such as to pump blood from the subject's left ventricle to the subject's aorta. Other applications are also described.

Abstract: Apparatus and methods are described including a tube configured to traverse a subject's aortic valve. A frame is disposed within a portion of the tube, and a plurality of winged projections are coupled to the frame. An impeller is disposed inside the tube, the impeller including at least one helical elongate element, and a film of material supported at least partially by the helical elongate element. The impeller is rotated, such as to pump blood from the subject's left ventricle to the subject's aorta. Blood flow that is generated by the rotation of the impeller is rectified, by using the winged projections to direct blood flow toward a direction of the longitudinal axis of the tube. Other applications are also described.