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 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 delivering a left-ventricular assist device to a subject's left ventricle. A tube is positioned such that a proximal portion of the tube traverses an aortic valve of the subject, and a distal portion of the tube is disposed within a left ventricle of the subject. A pump pumps blood through the tube from the subject's left ventricle to the subject's aorta. A curved element is disposed within the tube and is configured to cause at least a portion of the tube to become curved. Other applications are also described.

Abstract: Apparatus and methods are described including delivering a left-ventricular assist device to a subject's aorta. The device including a distal-tip element that defines a straight proximal portion, and a curved distal portion, the curved distal portion defining first and second curves with an elongated straight portion between the first and second curves. The distal-tip element is centered with respect to the aortic valve using the curved distal portion of the distal-tip element, to thereby guide the device through the subject's aortic valve atraumatically. A pump pumps blood through from the subject's left ventricle to the subject's aorta. Other applications are also described.

Abstract: Apparatus and methods are described including delivering a left-ventricular assist device to a subject's left ventricle. A tube is positioned such that a proximal portion of the tube traverses an aortic valve of the subject, and a distal portion of the tube is disposed within a left ventricle of the subject. A pump pumps blood through the tube from the subject's left ventricle to the subject's aorta such as to cause the proximal portion of the tube to be maintained in an open state, and to cause at least a portion of the tube to become curved. Other applications are also described.

Abstract: Apparatus and methods are described including an impeller (50) that includes a proximal bushing (64) and a distal bushing (58). Two or more helical elongate elements (52) extend from the proximal bushing (64) to the distal bushing (58), and an axial structure (54) is disposed inside of the two or more helical elongate elements (52), and along an axis around which the helical elongate elements (52) wind. The impeller (50) includes an impeller-overexpansion-prevention element (72). The impeller-overexpansion-prevention element is a single integrated structure that includes a ring (73) disposed around the axial structure (54), and a plurality of elongate elements (67) each of the elongate elements (67) extending from the ring to a respective helical elongate element (52) and being coupled to the respective helical elongate element (52) so as to prevent radial expansion of the impeller (50). 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 subject's left ventricle and to pump blood from the left ventricle to the subject's aorta, by rotating. A frame is disposed around the impeller. A tube traverses the subject's aortic valve, such that a proximal portion of the tube is disposed within the aorta and a distal portion of the tube is disposed within the left ventricle. The distal portion of the tube extends to the distal end of the frame and defines more than 10 blood-inlet openings that are sized such as (a) to allow blood to flow from the subject's left ventricle into the tube and (b) to block structures from the subject's left ventricle from entering into the frame. Other applications are also described.

Abstract: Apparatus and methods are described including a ventricular assist device configured to assist ventricular functioning of a subject. The ventricular assist device 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 being coupled to the axial shaft. The axial shaft includes a proximal portion and a distal portion, which are coupled to each other via a joint. The proximal portion and the distal portion of the axial shaft are configured to flex with respect to each other via the joint. Other applications are also described.

Abstract: Apparatus and methods are described including a ventricular assist device that includes a blood pump configured to be placed inside a left ventricle of a subject and to pump blood from the subject's left ventricle to an aorta of the subject. A blood pressure sensor measures aortic pressure of the subject. A computer processor varies a flow rate that is that is generated by the blood pump, and determines a relationship between arterial pulsatility of the subject and the flow rate that is generated by the blood pump, based upon aortic pressure that is measured by the blood pressure sensor as the flow rate that is generated by the blood pump is varied. The computer processor estimates native cardiac output of the subject at least partially based upon the relationship. Other applications are also described.

Abstract: Apparatus and methods are described including a ventricular assist device that includes a frame having struts that define a plurality of cells. In its non-radially-constrained configuration, the frame includes a generally cylindrical portion. A tube defines blood outlet openings, and a portion of the tube is disposed outside the frame and is coupled to the generally cylindrical portion of the frame, such that the portion of the tube conforms with a structure of struts of the frame. An inner lining is coupled to an inside of the generally cylindrical portion of the frame, such as to provide the generally cylindrical portion of the frame with a smooth inner surface. An impeller is disposed at least partially inside the generally cylindrical portion of the frame and is configured to pump blood through the tube and out of the one of more blood outlet openings. 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 generally 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. 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.

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 blood pump that is placed inside a body of subject. The blood pump includes an impeller that includes proximal and distal bushings, and that defines an axial lumen that extends from the proximal bushing to the distal bushing, a frame disposed around the impeller, and an axial shaft that passes through the proximal and distal bushings of the impeller. A distal end of a delivery catheter, and the frame and the impeller, are configured to be moved with respect to one another, to thereby cause the frame to assume a radially-constrained configuration by the frame becoming axially elongated, and cause the impeller to assume a radially-constrained configuration by the impeller becoming axially elongated. 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.

Abstract: Apparatus and methods are described, including a catheter (20) configured to be placed inside a blood vessel of a subject. A first impeller (28) is disposed on the catheter, and a second impeller (28) is disposed on the catheter, proximally to the first impeller. A support structure (160) is disposed upon the catheter such that a longitudinal center of the support structure is disposed between the first and second impellers, the support structure being configured to support an inner wall of the blood vessel in an open configuration in a region between the first and second 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 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 placing, into a subject's body, a blood-pump tube, with an impeller disposed within the blood-pump tube. At least one blood-pressure-measurement element extends to at least an outer surface of the blood-pump tube, such that the distal end of the blood-pressure-measurement element is in direct fluid communication with a bloodstream of the subject outside the blood-pump tube at a location that is proximal to blood-inlet opening(s) defined by the blood-pump tube. Blood is pumped through the blood-pump tube, using the impeller. Pressure of the bloodstream of the subject outside the blood-pump tube is measured by measuring blood pressure at the distal end of the left-ventricular blood-pressure-measurement element. Other applications are also described.

Abstract: Apparatus and methods are described including a ventricular assist device that includes an impeller configured to be placed inside a left ventricle of a subject. A driving magnet is coupled to a motor and is rotated by the motor. A driven magnet is magnetically coupled to the driving magnet and is rotated by the driving magnet. A drive cable extends from the driven magnet and imparts rotational motion from the driven magnet to the impeller. A set of sensors is configured to detect a magnetic phase difference between the driven magnet and the driving magnet. A computer processor receives the detected magnetic phase difference and determines a physiological parameter of the subject, at least partially in response thereto. 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.