Valve prosthesis
The present disclosure relates to valve replacement devices that are foldable for catheter-based deployment to the site of implantation, as well as systems for the delivery of valve prostheses, including prostheses having the special characteristics of the disclosed valve replacement devices. The devices include highly effective adhering mechanisms for secure and enduring precision implantation. The adhering mechanisms may employ a unique sealing mechanism that includes a cuff that expands slowly whereby the device is not secured in place until the completion of the implantation procedure. The implanted device, optionally together with the cuff, prevents perivalvular leaks and incorporate an appropriate leaflet system for reliable functioning in situ.
1. A method for replacing a damaged or diseased mitral valve in a subject comprising:
delivering to the mitral valve annulus of said subject a valve prosthesis that comprises
a stent having an expanded and an unexpanded state and that includes
a long axis;
a middle region having first and second ends and comprising a framework that defines inner and outer surfaces;
a lower flange portion at the first end of the middle region that comprises a plurality of flange elements, each of said elements having a first end that is attached to the middle region and an opposed second end that is spaced from the first end;
and,
an upper flange portion at the second end of the middle region that comprises a plurality of flange elements, each of said elements having a first end that is attached to the middle region and an opposed second end that is spaced from the first end;
and,
a valve that is attached to the inner surface of the middle region of the stent,
wherein,
when said stent is in the unexpanded state, the upper and lower flange portions are oriented substantially along the long axis of the stent;
when said stent transitions from the unexpanded state to the expanded state, the lower flange portion transitions in space so that it is no longer oriented substantially along the long axis of the stent; and,
the lower flange portion grasps tissue at the ventricular side of the annulus by enfolding it between the lower flange portion and the outer surface of the middle region as the stent transitions from the unexpanded state to the expanded state
and,
expanding said stent to anchor the prosthesis at the mitral valve annulus.
2. The method according to claim 1 wherein the valve prosthesis is delivered to the implantation site by a positioning catheter.
3. The method according to claim 1 wherein the valve prosthesis is delivered to the implantation site transatrially, transapically, or percutaneously.
4. The method according to claim 1 further comprising positioning said valve prosthesis at the implantation site after said delivering step.
5. The method according to claim 4 comprising positioning said valve prosthesis so that the lower flange portion anchors the stent within the mitral annulus by grasping tissue at the ventricular side of the annulus when said stent is expanded.
6. The method according to claim 5 comprising positioning said valve prosthesis so that the upper flange portion anchors the stent within the mitral annulus by grasping tissue at the atrial side of the annulus when said stent is expanded.
7. The method according to claim 5 wherein the lower flange portion anchors the stent within the mitral annulus by grasping the subvalvular apparatus at the ventricular side of the annulus.
8. The method according to claim 5 wherein the lower flange portion anchors the stent within the mitral annulus by grasping leaflets of the native mitral valve.