Heart assist device with expandable impeller pump
An impeller includes a hub and a blade supported by the hub. The impeller has a stored configuration in which the blade is compressed so that its distal end moves towards the hub, and a deployed configuration in which the blade extends away from the hub. The impeller may be part of a pump for pumping fluids, such as blood, and may include a cannula having a proximal portion with a fixed diameter, and a distal portion with an expandable diameter. The impeller may reside in the expandable portion of the cannula. The cannula may have a compressed diameter which allows it to be inserted percutaneously into a patient. Once at a desired location, the expandable portion of the cannula may be expanded and the impeller expanded to the deployed configuration. A flexible drive shaft may extend through the cannula for rotationally driving the impeller within the patient.
1. A catheter pump comprising:
a cannula comprising:
a non-expandable portion;
an expandable portion extending between a proximal end and a distal end;
a nose grommet;
a plurality of inlet struts extending between the nose grommet and the expandable portion distal end; and
a plurality of discharge struts extending between the non-expandable portion and the expandable portion proximal end; and
an impeller disposed in the cannula, the impeller sized and shaped to be inserted into a heart of a patient, wherein the impeller is configured to move axially out of the non-expandable portion and into the expandable portion for deployment.
2. The catheter pump of claim 1 , wherein the plurality of inlet struts are configured to prevent obstructions from entering the cannula.
3. The catheter pump of claim 1 , wherein the plurality of discharge struts are configured to act as stationary stator blades and remove swirl velocity from a discharge flow of the impeller.
4. The catheter pump of claim 1 , wherein the plurality of discharge struts are flat linear elements.
5. The catheter pump of claim 1 , wherein the plurality of discharge struts have an airfoil cross-section.
6. The catheter pump of claim 1 , wherein the expandable portion of the cannula comprises a mesh including a hexagonal cell matrix.
7. The catheter pump of claim 1 , wherein the expandable portion of the cannula comprises a mesh including a plurality of circumferential rings connected by axial connectors.
8. The catheter pump of claim 7 , wherein the mesh and the plurality of discharge struts are formed from a single tube.
9. The catheter pump of claim 1 , wherein a geometric density of the expandable portion varies along a length of the expandable portion.
10. The catheter pump of claim 1 , wherein the expandable portion is formed from a nitinol tube.
11. A cannula for a catheter pump, the cannula comprising:
a non-expandable portion;
an expandable portion extending between a proximal end and a distal end;
a nose grommet;
a plurality of inlet struts extending between the nose grommet and the expandable portion distal end, the plurality of inlet struts configured to transition from a closed configuration to an expanded configuration, wherein in the closed configuration, the plurality of inlet struts are folded down and radially compressed; and
a plurality of discharge struts extending between the non-expandable portion and the expandable portion proximal end.
12. The cannula of claim 11 , wherein the plurality of inlet struts are configured to prevent obstructions from entering the cannula.
13. The cannula of claim 11 , wherein the plurality of discharge struts are configured to act as stationary stator blades and remove swirl velocity from a discharge flow of an impeller positioned within the cannula.
14. The cannula of claim 11 , wherein the plurality of discharge struts are flat linear elements.
15. The cannula of claim 11 , wherein the plurality of discharge struts have an airfoil cross-section.
16. The cannula of claim 11 , wherein the expandable portion of the cannula comprises a mesh including a hexagonal cell matrix.
17. The cannula of claim 11 , wherein the expandable portion of the cannula comprises a mesh including a plurality of circumferential rings connected by axial connectors.
18. The cannula of claim 17 , wherein the mesh and the plurality of discharge struts are formed from a single tube.
19. The cannula of claim 11 , wherein a geometric density of the expandable portion varies along a length of the expandable portion.
20. The cannula of claim 11 , wherein the expandable portion is formed from a nitinol tube.