Abstract: Apparatus and methods are described including a ventricular assist device. An impeller is placed inside a left ventricle of a subject, the impeller defining a lumen therethrough. A frame is disposed around the impeller, with a proximal bearing disposed at a proximal end of the frame and a distal bearing disposed at a distal end of the frame. An axial shaft passes through the proximal bearing, the lumen defined by the impeller, and the distal bearing. A motion-cushioning spring is disposed around the axial shaft between a distal end of the impeller and the distal bearing, the motion-cushioning spring being configured to cushion axial motion that the impeller undergoes. Other applications are also described.

Abstract: Apparatus and methods are described including an impeller configured, in a radially-expanded configuration thereof, to pump a fluid by rotating. A radially expandable cage is disposed around the impeller, such that, in radially-expanded configurations of the impeller and the cage, the impeller is separated from an inner surface of the cage. The impeller is disposed within the cage such that, in response to the cage becoming radially contracted and axially elongated, the impeller radially contracts and axially elongates. 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, a frame disposed around the impeller, and a distal-tip portion disposed distally with respect to the frame. A duckbill valve is disposed entirely within a distal most 10 mm of the distal-tip portion. The duckbill valve defines a wide inlet and a narrow tip that defines a slit therethrough. The duckbill valve is proximally facing, such that the wide inlet faces a distal end of the distal-tip portion and such that the narrow tip faces away from the distal end of distal-tip portion. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an impeller configured to be delivered through vasculature of a subject while the impeller is in a radially-constrained configuration. The impeller is configured to self-expand to a non-radially-constrained configuration, and to pump blood while in the non-radially-constrained configuration. A ratio between (a) a diameter of the impeller when the impeller is in its non-radially-constrained configuration at a location at which the diameter of the impeller is at its maximum and (b) a diameter of the impeller when the impeller is in its radially-constrained configuration is greater than 7:2. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an impeller having proximal and distal end portions, a frame disposed around the impeller, and a shaft member that passes through the proximal and distal end portions of the impeller and that is configured to impart rotational motion to the impeller. The impeller defines a radially-constrained configuration in which the impeller is introduced into a subject's body and a non-radially-constrained configuration in which the impeller is configured to pump blood within the subject's body. The distal end portion of the impeller is configured to slide over the shaft member as the impeller changes from its radially-constrained configuration to its non-radially-constrained configuration. Other applications are also described.

Abstract: Apparatus and methods are described, including a left-ventricular assist device that includes an impeller, and a frame disposed around the impeller, the frame having a length of more than 25 mm when disposed in a non-radially constrained configuration. A rigid axial shaft extends from a proximal end of the frame to a distal end of the frame. A motor is disposed outside a body of a subject, and drives the impeller to pump blood within the subject's body, by rotating. A drive cable extends from outside the subject's body to the axial shaft. The drive cable imparts rotational motion from the motor to the impeller by rotating. The drive cable is a flexible cable comprising a plurality of coiled wires. Other applications are also described.

Abstract: Apparatus and methods are described including a left ventricular assist device. The left ventricular assist device includes an impeller configured to be placed inside a subject's left ventricle, and to pump blood from the subject's 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 subject's aorta and a distal portion of the tube is disposed within the subject's left ventricle. The distal portion of the tube defines one or more blood inlet openings that are configured to allow blood to flow from the subject's left ventricle into the tube. A braided element is configured to prevent inner structures of the left ventricle from passing into the one or more blood inlet openings. Other applications are also described.

Abstract: Apparatus and methods are described including a left ventricular assist device. The left ventricular assist device includes an impeller configured to be placed inside a subject's left ventricle, and to pump blood from the subject's 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 subject's aorta and a distal portion of the tube is disposed within the subject's left ventricle. The distal portion of the tube defines one or more blood inlet openings that are configured to allow blood to flow from the subject's left ventricle into the tube. A mesh is configured to prevent inner structures of the left ventricle from passing into the one or more blood inlet openings. 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 configured to pump the subject's blood by rotating, and an axial shaft upon which the impeller is disposed. Proximal and distal radial bearings are configured to stabilize the axial shaft radially during rotation of the impeller. An atraumatic distal-tip portion is disposed distally with respect to the impeller, the atraumatic distal-tip portion including an inflatable portion. A purging fluid is pumped toward the distal-tip portion, such as to (a) purge the distal bearing, and (b) inflate the inflatable portion of the distal-tip portion. 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, and a frame configured to be disposed around the impeller. The frame is shaped such that, in a non-radially constrained configuration of the frame, the frame defines a cylindrical central portion, and a distal conical portion that is disposed distally with respect to the cylindrical central portion and that widens from a distal end of the frame to a distal end of the cylindrical central portion. The frame defines struts that define openings therebetween, and all openings that are defined at least partially within the distal conical portion of the frame extend into the cylindrical central portion of the frame. Other applications are also described.

Abstract: Apparatus and methods are described for improving renal function of a patient, including mechanically occluding the patient's inferior vena cava downstream of the renal vein ostium to form an upstream region and a downstream region of the inferior vena cava, and mechanically pumping blood through the inferior vena cava from the upstream region to a discharge location in the downstream region while the inferior vena cava is occluded, wherein the blood remains in the inferior vena cava while being mechanically pumped. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes a catheter, a first impeller disposed on the catheter, and a second impeller disposed on the catheter, proximally to the first impeller. A motor drives the first and second impellers to pump blood of a subject, by driving the first and second impellers to rotate. The blood pumps is configured such that (a) the first and second impellers are shaped differently from each other when the first and second impellers are in non-radially-constrained configurations, (b) the first and second impellers are sized differently from each other when the first and second impellers are in non-radially-constrained configurations, and/or (c) the first and second impellers are driven by the motor to rotate under respective rotation conditions that are different from each other. 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 subject's left ventricle. A frame is disposed around the impeller, the frame defining generally-cylindrical central portion, and a proximal conical portion that widens from a proximal end of the frame to a proximal end of the generally-cylindrical central portion. A motor drives the impeller to pump blood from the left ventricle to the subject's aorta, by rotation of the impeller. The impeller is configured to be disposed at least partially within the proximal conical portion of the frame during at least some of a time during which the impeller rotates. 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 identifying a subject as suffering from a condition that causes the subject to have elevated central venous pressure. In response thereto, a device is placed inside the subject's vena cava, and the device is deployed inside the subject's vena cava, such that, in a passive manner, the device reduces blood pressure within the subject's renal veins relative to the subject's central venous pressure. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes an axial shaft, an impeller disposed on the axial shaft, a frame disposed around the impeller, and a motor disposed outside a subject's body, and configured to drive the impeller to pump blood from a distal end of the impeller to a proximal end of the impeller. A drive cable extends from outside the subject's body to the axial shaft, and is configured to impart rotational motion from the motor to the impeller by rotating. The drive cable is held in a preloaded state with respect to the frame, such that initiation of pumping of blood by rotation of the impeller does not cause the drive cable to axially elongate. 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 catheter, and first and second impellers configured to be inserted into a subject's body via the catheter, the first and second impellers being disposed in series with each other. A first impeller cage is disposed around the first impeller, and a second impeller cage is disposed around the second impeller. A sleeve extends longitudinally along more than 50 percent of a distance between the first and second impellers. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes at least one motor configured to be disposed outside a body of a subject, a catheter, a proximal impeller disposed on the catheter and configured to pump blood by rotating, and a distal impeller disposed on the catheter. The distal impeller is configured to pump blood by rotating and is disposed on the catheter distally to the proximal impeller such that longitudinal centers of the proximal and distal impellers are separated from each other by at least 3 cm. Other applications are also described.

Abstract: Apparatus and methods are described including a blood pump that includes a catheter, a first impeller disposed on the catheter, and a second impeller disposed on the catheter, proximally to the first impeller. A motor drives the first and second impellers to pump blood of a subject, by driving the first and second impellers to rotate. The blood pumps is configured such that (a) the first and second impellers are shaped differently from each other when the first and second impellers are in non-radially-constrained configurations, (b) the first and second impellers are sized differently from each other when the first and second impellers are in non-radially-constrained configurations, and/or (c) the first and second impellers are driven by the motor to rotate under respective rotation conditions that are different from each other. Other applications are also described.