Curved tube for a ventricular assist device
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.
1. An apparatus including:
a left-ventricular assist device configured to assist left-ventricular functioning of a subject, the left-ventricular assist device comprising:
a tube configured 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, the tube defining a set of one or more blood-inlet openings that are configured to be disposed within the subject's left ventricle, and a set of one or more blood-outlet openings that are configured to be disposed within the subject's aorta;
a frame disposed within the distal portion of the tube, the frame being configured to hold the distal portion of the tube in an open state,
the frame not being disposed within the proximal portion of the tube, and the proximal portion of the tube thereby being configured to collapse inwardly in response to pressure outside of the proximal portion of the tube exceeding pressure inside the proximal portion of the tube;
a pump disposed within the frame and configured to pump blood through the tube from the subject's left ventricle to the subject's aorta, by pumping the blood into the tube via the one or more blood-inlet openings and by pumping blood out of the tube via the one or more blood-outlet openings,
wherein the tube is configured such that during pumping of the blood through the tube the proximal portion of the tube is maintained in an open state, and
wherein the tube is pre-shaped such that during pumping of the blood through the tube at least a portion of the tube becomes curved.
2. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube at least the portion of the tube becomes curved, such that the tube curves away from a posterior wall of the left ventricle.
3. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube at least the portion of the tube becomes curved, such that the tube curves away from a septal wall of the left ventricle.
4. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube at least the portion of the tube becomes curved, such that the tube curves toward a free wall of the left ventricle.
5. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube at least the portion of the tube becomes curved, such that the tube curves toward an apex of the left ventricle.
6. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube at least the portion of the tube becomes curved, such that a separation is maintained between the one or more blood-inlet openings and a posterior wall of the left ventricle, mitral valve leaflets of the subject, chordae tendineae of the subject, and papillary muscles of the subject.
7. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube at least the portion of the tube becomes curved, by the tube having been pre-shaped using a molding process.
8. The apparatus according to claim 1 , wherein the tube is pre-shaped such that during pumping of the blood through the tube a portion of the tube which is proximal to the frame and which is disposed within the left ventricle become curved.
9. The apparatus according to claim 1 , further comprising a curved element disposed within the tube, the curved element being configured to cause at least the portion of the tube to become curved.
10. The apparatus according to claim 9 , wherein the curved element is disposed proximally with respect to the frame.
11. The apparatus according to claim 9 , wherein the curved element is configured to cause at least the portion of the tube to become curved, such that the tube curves away from a posterior wall of the left ventricle.
12. The apparatus according to claim 9 , wherein the curved element is configured to cause at least the portion of the tube to become curved, such that the tube curves away from a septal wall of the left ventricle.
13. The apparatus according to claim 9 , wherein the curved element is configured to cause at least the portion of the tube to become curved, such that a separation is maintained between the one or more blood-inlet openings and the posterior wall of the left ventricle, mitral valve leaflets of the subject, chordae tendineae of the subject, and papillary muscles of the subject.
14. The apparatus according to claim 1 , wherein at least one of the sets of blood-inlet openings and blood-outlet openings is disposed in a non-axi-symmetric configuration with respect to the tube, such that pumping of the blood through the at least one of the sets of blood-inlet openings and blood-outlet openings causes at least a portion of the tube to become curved, such that the curvature of the tube is maintained.
15. The apparatus according to claim 14 , wherein the one or more blood-inlet openings are disposed on a side of the tube that is inside of the curve of the tube such that as blood flows into the blood-inlet openings, pressure in a region above the blood-inlet openings is lowered, and a distal end of the tube is then pulled toward this region.
16. The apparatus according to claim 14 , wherein the one or more blood-outlet openings are disposed on a side of the tube that is inside of the curve of the tube such that as blood exits the blood-outlet openings the blood impacts a wall of the aorta, causing a proximal end of the tube to be pushed in an opposite direction from the flow of the blood exiting the blood-outlet openings.
17. A method comprising:
delivering a left-ventricular assist device to a left ventricle of a subject, the left-ventricular assist device including:
a tube configured 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, the tube defining a set of one or more blood-inlet openings that are configured to be disposed within the subject's left ventricle, and a set of one or more blood-outlet openings that are configured to be disposed within the subject's aorta,
a frame disposed within the distal portion of the tube, the frame being configured to hold the distal portion of the tube in an open state,
the frame not being disposed within the proximal portion of the tube, and the proximal portion of the tube thereby being configured to collapse inwardly in response to pressure outside of the proximal portion of the tube exceeding pressure inside the proximal portion of the tube,
a pump disposed within the frame; and
operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta, by pumping the blood into the tube via the one or more blood-inlet openings and by pumping blood out of the tube via the one or more blood-outlet openings, and such as to:
cause the proximal portion of the tube is maintained in an open state, and cause at least a portion of the tube to become curved.
18. The method according to claim 17 , wherein operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta comprises causing at least the portion of the tube to become curved, such that the tube curves away from a posterior wall of the left ventricle.
19. The method according to claim 17 , wherein operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta comprises causing at least the portion of the tube to become curved, such that the tube curves away from a septal wall of the left ventricle.
20. The method according to claim 17 , wherein operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta comprises causing at least the portion of the tube to become curved, such that the tube curves toward a free wall of the left ventricle.
21. The method according to claim 17 , wherein operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta comprises causing at least the portion of the tube to become curved, such that the tube curves toward an apex of the left ventricle.
22. The method according to claim 17 , wherein operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta comprises causing at least the portion of the tube to become curved, such that a separation is maintained between the one or more blood-inlet openings and a posterior wall of the left ventricle, mitral valve leaflets of the subject, chordae tendineae of the subject, and papillary muscles of the subject.
23. The method according to claim 17 , wherein operating the pump to pump blood through the tube from the subject's left ventricle to the subject's aorta comprises causing at least a portion of the tube which is proximal to the frame and which is disposed within the left ventricle to become curved.