Blood pumps
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 motor is configured to generate rotational motion. A rotation shaft extends from the motor to the first impeller and imparts the rotational motion from the motor to the first impeller. A gear mechanism disposed between the first and second impeller is configured to effect a change in rotational motion that is imparted from the first impeller to the second impeller, such that the second impeller rotates in a different manner from the first impeller. Other applications are also described.
1. An apparatus comprising:
a catheter;
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 motor configured to generate rotational motion;
a rotation shaft configured to extend from the motor to the first impeller and to impart rotational motion from the motor to the first impeller; and
a gear mechanism disposed between the first and second impeller and configured to effect a change in rotational motion that is imparted from the first impeller to the second impeller, so that the second impeller rotates in a different manner from the first impeller.
2. The apparatus according to claim 1 , wherein the first and second impellers are configured to rotate in opposite directions from each other.
3. The apparatus according to claim 1 , wherein the first and second impellers are configured to rotate in the same direction as each other.
4. The apparatus according to claim 1 , wherein the first and second impellers are configured to rotate at different rates of rotation from each other.
5. The apparatus according to claim 1 , wherein the first and second impellers are configured to rotate at the same rate of rotation as each other.
6. The apparatus according to claim 1 , wherein the first and second impellers are configured to pump blood in opposite directions from each other.
7. The apparatus according to claim 1 , wherein the first and second impellers are configured to pump blood in the same direction as each other.
8. The apparatus according to claim 1 , wherein the first and second impellers are configured to generate a region within a blood vessel that is of lower blood pressure than elsewhere within the blood vessel by pumping blood away from a region of the blood vessel between the first and second impellers.
9. The apparatus according to claim 1 , further comprising:
a first impeller cage configured to be disposed around the first impeller;
a second impeller cage configured to be disposed around the second impeller; and
a support sleeve configured to extend longitudinally along more than 50 percent of a region between the first and second impellers.
10. The apparatus according to claim 9 , wherein at least one end of the support sleeve is open so that the first impeller cage and the first impeller are able to pass through the open end of the support sleeve even when the first impeller cage and the first impeller are in radially non-constrained configurations thereof.
11. The apparatus according to claim 9 , wherein the first impeller cage and the support sleeve are cut from a single piece of a shape memory alloy.
12. The apparatus according to claim 9 , wherein the support sleeve is configured to extend at least from a longitudinal center of the first impeller to a longitudinal center of the second impeller.
13. The apparatus according to claim 9 , wherein the first and second impeller cages are integrally formed with the support sleeve.
14. The apparatus according to claim 9 , wherein the first and second impeller cages are separately formed from the support sleeve.
15. An apparatus comprising:
a catheter;
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 motor configured to generate rotational motion;
a first rotation shaft configured to extend from the first motor to the first impeller and to impart rotational motion from the first motor to the first impeller;
a second motor configured to generate rotational motion;
a second rotation shaft that is coaxial with the first rotation shaft, the second rotation shaft being configured to extend from the second motor to the second impeller and to impart rotational motion from the second motor to the second impeller;
a first impeller cage configured to be disposed around the first impeller;
a second impeller cage configured to be disposed around the second impeller; and
a support sleeve configured to extend longitudinally along more than 50 percent of a region between the first and second impellers.
16. The apparatus according to claim 15 , wherein the first and second impellers are configured to rotate in opposite directions from each other.
17. The apparatus according to claim 15 , wherein the first and second impellers are configured to rotate in the same direction as each other.
18. The apparatus according to claim 15 , wherein the first and second impellers are configured to rotate at different rates of rotation from each other.
19. The apparatus according to claim 15 , wherein the first and second impellers are configured to rotate at the same rate of rotation as each other.
20. The apparatus according to claim 15 , wherein the first and second impellers are configured to pump blood in opposite directions from each other.
21. The apparatus according to claim 15 , wherein the first and second impellers are configured to pump blood in the same direction as each other.
22. The apparatus according to claim 15 , wherein the first and second impellers are configured to generate a region within a blood vessel that is of lower blood pressure than elsewhere within the blood vessel by pumping blood away from a region of the blood vessel between the first and second impellers.
23. The apparatus according to claim 15 , wherein at least one end of the support sleeve is open so that the first impeller cage and the first impeller are able to pass through the open end of the support sleeve even when the first impeller cage and the first impeller are in radially non-constrained configurations thereof.
24. The apparatus according to claim 15 , wherein the first impeller cage and the support sleeve are cut from a single piece of a shape memory alloy.
25. The apparatus according to claim 15 , wherein the support sleeve is configured to extend at least from a longitudinal center of the first impeller to a longitudinal center of the second impeller.
26. The apparatus according to claim 15 , wherein the first and second impeller cages are integrally formed with the support sleeve.
27. The apparatus according to claim 15 , wherein the first and second impeller cages are separately formed from the support sleeve.