Reciprocating intravascular blood pump

1. Apparatus configured to be deployed in a lumen of a blood vessel of a subject, the apparatus comprising:

a reciprocating device configured to move downstream and upstream in the blood vessel in a reciprocating pattern to provide:

a first effective surface area of the device for pushing blood downstream in the blood vessel during downstream motion of the reciprocating device, and

a second effective surface area of the device during upstream motion of the reciprocating device, the first effective surface area being larger for pushing blood in the blood vessel than the second effective surface area; and

a device driver configured to drive the reciprocating device in the reciprocating pattern at a frequency of 2-5 Hz.

2. The apparatus according to claim 1 , wherein the reciprocating device comprises a flexible membrane.

3. The apparatus according to claim 1 , wherein the blood vessel is an aorta of the subject, and wherein the apparatus is configured to be deployed in the aorta.

4. The apparatus according to claim 1 , wherein the apparatus is not configured to coordinate the reciprocating pattern with a cardiac cycle of the subject.

5. The apparatus according to claim 1 , wherein the apparatus does not comprise any sensor of heart rate or cardiac cycle.