Devices and Methods for Reducing Mitral Valve Regurgitation

Abstract

A mitral valve annulus reshaping device includes at least a portion that is formed of a biocompatible shape memory alloy SMA having a characteristic temperature, A f , that is preferably below body temperature. The device is constrained in an unstable martensite (UM) state while being introduced through a catheter that passes through the venous system and into the coronary sinus of the heart. The reshaping device is deployed adjacent to the mitral valve annulus of the heart as it is forced from the catheter. When released from the constraint of the catheter, the SMA of the device at least partially converts from the UM state to an austenitic state and attempts to change to a programmed shape that exerts a force on the adjacent tissue and modifies the shape of the annulus. The strain of the SMA can be varied when the device is within the coronary sinus.

1 . A method of treating mitral valve regurgitation in a patient's heart, the method comprising:
 delivering a mitral valve device to a coronary sinus of the patient, the mitral valve device comprising a first expandable anchor, a second expandable anchor, and a connecting member connecting the first and second anchors;   expanding the first anchor in the coronary sinus from a delivery configuration and fixing the first anchor to a portion of the coronary sinus;   applying a proximally directed force on the connecting member to pull the portion of the coronary sinus to which the first anchor is fixed in the proximal direction, wherein applying the proximally directed force causes the connecting member to straighten and mitral valve regurgitation to be reduced; and   expanding the second anchor within the coronary sinus from a delivery configuration and fixing the second anchor to a portion of the coronary sinus after mitral valve regurgitation has been reduced.   
     
     
         2 . The method of  claim 1  wherein expanding the first anchor in the coronary sinus comprises allowing the first anchor to self-expand. 
     
     
         3 . The method of  claim 1  wherein applying a proximally directed force on the connector comprises applying a proximally directed force on a central portion of the connector. 
     
     
         4 . The method of  claim 1  wherein applying a proximally directed force on the connector comprises applying a proximally directed force on a spring portion of the connector. 
     
     
         5 . The method of  claim 1  wherein causes the connector to straighten causes a portion of the mitral valve annulus to straighten. 
     
     
         6 . The method of  claim 5  wherein a posterior portion of the annulus is straightened. 
     
     
         7 . The method of  claim 1  wherein expanding the second anchor comprises allowing the second anchor to self-expand.