Methods and apparatus for engaging a valve prosthesis with tissue
A prosthetic valve comprises a self-expanding frame which includes a self-expanding atrial skirt that forms a flanged region, a self-expanding ventricular skirt, and a first self-expanding tab coupled with the ventricular skirt. A receptacle for receiving a valve leaflet is formed by the area bounded by an outer surface of the atrial skirt, an outer surface of the ventricular skirt, and an inner surface of the first tab. The receptacle has a window for receiving the valve leaflet that is defined by a gap between an edge of the flange and a tip of the first tab. The gap is maximized when the tip of the first tab is unconstrained and a base of the first tab is at least partially constrained. The gap is minimized when the tip of the first tab and its base are unconstrained.
1. A system for deploying a prosthetic valve, said system comprising:
a prosthetic cardiac valve comprising an atrial skirt, a ventricular skirt, and a tab coupled to the ventricular skirt; and
a delivery system comprising an outer sheath and pusher element, wherein the prosthetic cardiac valve is carried by the delivery system and the pusher element is slidably disposed under the outer sheath,
wherein partial retraction of the outer sheath releases a constraint from the atrial skirt and the ventricular skirt thereby allowing self-expansion thereof, and
wherein further retraction of the outer sheath releases a constraint from the tab thereby allowing a tip of the tab to radially self-expand outward forming a window between an edge of the atrial skirt and the tip of the tab, and
wherein a base portion of the tab remains constrained by the outer sheath and actuation of the pusher element into engagement with the base portion actuates the tip of the tab to open the window to its maximum size, and
wherein further retraction of the outer sheath or further actuation of the pusher element removes the constraint from the base portion of the tab, thereby at least partially closing the window.
2. The system of claim 1 , wherein the base portion self-expands radially outward when the constraint is released therefrom, and wherein the tip of the tab moves toward the edge of the atrial skirt to close the window.
3. The system of claim 1 , further comprising a cover disposed at least partially over the prosthetic cardiac valve, thereby facilitating tissue ingrowth.
4. The system of claim 3 , wherein the cover comprises fabric, tissue, or a polymer.
5. The system of claim 1 , wherein the tip of the tab is adapted to engage a fibrous trigone.
6. The system of claim 1 , wherein the tab is adapted to engage an anterior or a posterior mitral valve leaflet.
7. The system of claim 1 , wherein the atrial skirt expands before the tab.
8. The system of claim 1 , wherein the atrial skirt anchors the prosthetic cardiac valve to the atrium before the tab anchors the prosthetic cardiac valve to a valve leaflet.
9. The system of claim 1 , wherein the tab expands to a position transverse to a longitudinal axis of the prosthetic cardiac valve followed by expansion to a position substantially parallel to the longitudinal axis of the prosthetic cardiac valve.