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.

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.

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.

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.

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.

An inflow cannula for an implantable blood pump, the inflow cannula defining an inlet at a proximal end, an opposite distal end, and a lumen therebetween, the inflow cannula being configured to constrict the lumen

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.

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.

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.

The disclosure relates to devices and methods for the treatment of edema, which devices use a restrictor for flow compensation. Devices and methods of the invention further use a flow-restrictor in the circulatory system, upstream of an intravascular pump, to balance pressure changes induced by the pump and to compensate for downstream flow. The device may be provided as an indwelling, intravascular catheter with a mechanical pump such as an impeller and a selectively deployable restrictor such as an inflatable balloon. Congestive heart failure or edema is treated by \ operating the pump in an innominate vein and using the restrictor for flow compensation, to restrict the upstream flow and thus amplify or maintain pressure reduction at the lymphatic outlet.