Frame for prosthetic heart valve

1. A prosthetic heart valve that is radially collapsible to a collapsed configuration and radially expandable to an expanded configuration, comprising:

an annular inner frame comprising a plurality of angled first strut members, the inner frame being configured to foreshorten from a first length corresponding to the collapsed configuration to a second length corresponding to the expanded configuration when the prosthetic heart valve is expanded to the expanded configuration;

a leaflet structure situated at least partially within the inner frame; and

an outer frame disposed radially outward of the inner frame and coupled to the inner frame, the outer frame being configured to collapse with the inner frame to the collapsed configuration and expand with the inner frame to the expanded configuration, the outer frame comprising a plurality of second strut members;

wherein at least respective portions of the second strut members are configured to bend radially outwardly into a curved shape as the inner frame and the outer frame move from the collapsed configuration to the expanded configuration; and

wherein the prosthetic heart valve further comprises a skirt member disposed between the second strut members and the inner frame and secured to the second strut members.

2. The prosthetic heart valve of claim 1 , wherein:

the second strut members comprise first and second end portions; and

the first and second end portions of the second strut members are coupled to the outer inner frame such that the first and second end portions move toward each other as the outer frame expands to bend the second strut members into the curved shape.

3. The prosthetic heart valve of claim 1 , wherein:

the inner frame comprises an inflow end and an outflow end; and

the second strut members extend from the inflow end of the inner frame to the outflow end.

4. The prosthetic heart valve of claim 1 , wherein the outer frame further comprises circumferentially-extending strut members that interconnect the second strut members.

5. The prosthetic heart valve of claim 1 , wherein:

the inner frame comprises an inflow end and an outflow end; and

the second strut members are situated around the inner frame, and each of the second strut members branches into two third strut members adjacent the inflow end of the inner frame.

6. The prosthetic heart valve of claim 5 , wherein the third strut members extending from a given second strut member curve radially away from the inner frame and are coupled to third strut members of adjacent second strut members.

7. The prosthetic heart valve of claim 6 , wherein when the prosthetic heart valve is in the expanded configuration, the second strut members form a first portion of the outer frame having a convex exterior surface, and the third strut members form a second portion of the outer frame comprising an annular flange.

8. The prosthetic heart valve of claim 7 , wherein the second strut members comprise apices spaced radially away from the inner frame when the prosthetic heart valve is in the expanded configuration.

9. The prosthetic heart valve of claim 6 , further comprising a skirt member secured to the third strut members.

10. The prosthetic heart valve of claim 1 , wherein the second strut members comprise tissue-engaging members configured to extend radially outwardly from the second strut members when the second strut members are in the curved shape.

11. A method, comprising:

introducing the prosthetic heart valve of claim 1 into a patient's vasculature in the radially collapsed configuration;

advancing the prosthetic heart valve to a treatment site; and

radially expanding the prosthetic heart valve such that the inner frame foreshortens and the second strut members of the outer frame bend into the curved shape.

12. A prosthetic heart valve that is radially collapsible to a collapsed configuration and radially expandable to an expanded configuration, comprising:

an annular frame comprising a plurality of angled first strut members, the frame being configured to foreshorten from a first length corresponding to the collapsed configuration to a second length corresponding to the expanded configuration when the prosthetic heart valve is expanded to the expanded configuration;

a leaflet structure situated at least partially within the frame; and

a plurality of second strut members extending longitudinally along at least a portion of the frame and coupled to the frame;

wherein the second strut members are configured to bend radially outwardly as the frame moves from the collapsed configuration to the expanded configuration such that at least one of the second strut members forms a first apex and a second apex spaced radially outwardly from the frame when the prosthetic heart valve is in the expanded configuration, and wherein the second apex is spaced radially outwardly from the frame by a greater distance than the first apex.

13. The prosthetic heart valve of claim 12 , wherein at least a portion of the plurality of second strut members comprise tissue-engaging members configured to extend away from the second strut members when the prosthetic heart valve is in the expanded configuration.

14. The prosthetic heart valve of claim 13 , wherein the tissue-engaging members extend from apices of the second strut members.

15. A prosthetic heart valve that is radially collapsible to a collapsed configuration and radially expandable to an expanded configuration, comprising:

an annular frame comprising a plurality of angled first strut members, the frame being configured to foreshorten from a first length corresponding to the collapsed configuration to a second length corresponding to the expanded configuration when the prosthetic heart valve is expanded to the expanded configuration;

a leaflet structure situated at least partially within the frame;

a plurality of second strut members extending longitudinally along at least a portion of the frame and coupled to the frame, the second strut members being arranged circumferentially around the frame in a first row and configured to bend radially outwardly from the frame into a curved shape as the frame moves from the collapsed configuration to the expanded configuration; and

a plurality of third strut members extending longitudinally along at least a portion of the frame and coupled to the frame, the third strut members being arranged circumferentially around the frame in a second row and configured to bend radially outwardly from the frame into a curved shape as the frame moves from the collapsed configuration to the expanded configuration;

wherein the second strut members of the first row are circumferentially offset from the third strut members of the second row.

16. The prosthetic heart valve of claim 15 , wherein the second strut members at least partially overlap with the third strut members in an axial direction when the prosthetic heart valve is in the expanded configuration.

17. The prosthetic heart valve of claim 15 , wherein the third strut members comprise reduced width portions configured to induce bending of the third strut members at the reduced width portions.

18. The prosthetic heart valve of claim 15 , wherein at least a portion of the plurality of second strut members comprise tissue-engaging members configured to extend away from the second strut members when the prosthetic heart valve is in the expanded configuration.

19. The prosthetic heart valve of claim 1 , wherein:

the inner frame comprises an inflow end and an outflow end; and

the second strut members of the outer frame comprise apices when the inner frame is in the expanded configuration, and the apices define a shoulder of the outer frame that is closer to the inflow end of the inner frame than to the outflow end of the inner frame.

20. The prosthetic heart valve of claim 1 , wherein the second strut members of the outer frame are sutured to the inner frame.