Cardiac valve support structure

1. A two-step method of replacing a patient's mitral valve, comprising:

endovascularly delivering a valve support to a location near a subject′s mitral valve, the valve support comprising a first support element, a second support element, and first and second bridging members extending from the first and second support elements, wherein said valve support is configured to have a collapsed delivery configuration and an expanded deployed configuration;

expanding the first support element from a collapsed first support delivery configuration to a deployed first support configuration secured against cardiac tissue below the plane of the mitral valve annulus;

expanding the bridge members from collapsed bridge delivery configurations to expanded bridge deployed configurations positioned in general alignment with the coaptation points of the native mitral valve leaflets; and

expanding the second support element from a collapsed second support delivery configuration to an expanded second support deployed configuration secured against left atrial tissue above the plane of the mitral valve annulus;

wherein the native valve leaflets function after said expansion of said second support element;

and subsequently delivering a replacement mitral valve and securing said replacement mitral valve to the valve support.

2. The method of claim 1 , wherein expanding the first support element comprises allowing the first support element to self-expand against cardiac tissue.

3. The method of claim 1 , wherein expanding each of the bridge members comprises allowing the bridge members to assume the expanded deployed bridge configuration in which the bridge members extend radially inward from the first and second support elements.

4. The method of claim 1 , wherein expanding the second support element against left atrial tissue comprises allowing the second support element to self-expand.

5. The method of claim 1 , wherein expanding the first support element comprises expanding the first support element to the expanded first support deployed configuration having a generally annular shape.

6. The method of claim 1 , wherein expanding the first support element comprises expanding the first support element secured against papillary tendons.

7. The method of claim 6 , wherein expanding the first support element comprises expanding the first support element secured against papillary tendons without displacing the papillary tendons.

8. The method of claim 1 , wherein expanding the first support element occurs before expanding the second support element.

9. The method of claim 1 , wherein expanding the bridge members comprises allowing the bridge members to symmetrically extend from the first support element to the second support element.

10. The method of claim 1 , wherein expanding the bridge members comprises allowing the bridge members to extend from the first and second support elements about 180 degrees from one another.

11. The method of claim 1 , wherein expanding the second support element comprises expanding the second support element to the expanded second support deployed configuration in which the second support element has a dimension larger than a dimension of the first support element in the expanded first support deployed configuration.

12. The method of claim 1 , wherein securing the replacement mitral valve to the valve support comprises expanding the replacement mitral valve from a collapsed valve delivery configuration to an expanded valve deployed configuration.

13. The method of claim 12 , wherein expanding the replacement mitral valve comprises expanding the replacement mitral valve with a balloon.

14. The method of claim 12 , wherein expanding the replacement mitral valve comprises allowing the replacement mitral valve to self-expand.

15. The method of claim 1 , wherein securing the replacement mitral valve to the valve support comprises securing the replacement mitral valve radially within the valve support.

16. The method of claim 1 , wherein securing the replacement mitral valve to the valve support comprises locking a replacement mitral valve element with a valve support element to lock the replacement mitral valve to the valve support.

17. The method of claim 16 , wherein the bridge members each comprise a bridge lock element and the replacement mitral valve comprises a plurality of lock elements, and the locking step comprises locking one of the plurality of lock elements with one of the bridge lock elements and locking a second of the plurality of lock elements with the other of the bridge lock elements.