Collapsible and re-expandable prosthetic heart valve cuff designs and complementary technological applications
A prosthetic heart valve is provided with a cuff having features which promote sealing with the native tissues even where the native tissues are irregular. The cuff may include a portion adapted to bear on the LVOT when the valve is implanted in a native aortic valve. The valve may include elements for biasing the cuff outwardly with respect to the stent body when the stent body is in an expanded condition. The cuff may have portions of different thickness distributed around the circumference of the valve in a pattern matching the shape of the opening defined by the native tissue. All or part of the cuff may be movable relative to the stent during implantation.
1. A prosthetic heart valve for replacement of a native heart valve having a native valve annulus, comprising:
(a) a stent body having a proximal end and a distal end and including a generally tubular annulus region and a flare section proximal to the annulus region, the stent body having a proximal-to-distal axis, a radially collapsed condition, and an unconstrained, fully radially expanded condition, the annulus region and the flare section increasing in diameter during transition from the radially collapsed condition to the radially expanded condition, the flare section extending from the annulus region to the proximal end of the stent, the flare section having a diameter which increases progressively in the proximal direction over the entire flare section from a diameter equal to a diameter of the annulus region at a juncture between the annulus region and the flare section to a diameter at the proximal end of the stent greater the diameter of the annulus region when the stent body is in the unconstrained, fully radially expanded condition, wherein the stent body further includes an aortic section distal to the annulus region, the aortic section having a larger diameter than a proximalmost end of the stent when the stent body is in the unconstrained, fully radially expanded condition, wherein in the unconstrained, fully radially expanded condition of the stent body, an ablumenal surface of the flare section is continuously concave from the annulus region to the proximalmost end of the stent;
(b) one or more prosthetic valve elements mounted to the stent body and operative to allow flow in the antegrade direction through the annulus region but to substantially block flow in the retrograde direction through the annulus region; and
(c) a cuff secured to the stent body, the cuff comprising
(i) a first cuff portion covering at least a portion of an exterior surface of the annulus region for disposition at the native valve annulus, the first cuff portion having a substantially constant first diameter when the stent body is in the unconstrained, fully radially expanded condition, and
(ii) a second cuff portion proximal to the first cuff portion and integral with the first cuff portion, at least a part of the second cuff portion extending along an exterior surface of the flare section of the stent body, the second cuff portion having a diameter which increases progressively in the proximal direction to a second diameter when the stent body is in the radially expanded condition, the second diameter being greater than the first diameter, the second cuff portion being adapted for engagement with native tissue proximal to the native valve annulus.
2. A valve as claimed in claim 1 , wherein the one or more valve elements include a plurality of flexible prosthetic valve leaflets disposed at least partially within the annulus region.
3. A valve as claimed in claim 2 , wherein the plurality of leaflets are secured to the cuff along leaflet bases, at least a part of the second cuff portion extending between the leaflet bases and a proximal edge of the cuff.
4. A valve as claimed in claim 1 , wherein the stent is fully self-expanding.
5. A valve as claimed in claim 1 , wherein the aortic section has a larger diameter than the annulus region when the stent body is in the unconstrained, fully radially expanded condition.
6. A valve as claimed in claim 1 , wherein the stent body includes a transition section between the annulus region and the aortic section, an ablumenal surface of the transition section being continuously concave from the annulus region to the aortic region in the unconstrained, fully radially expanded condition of the stent body.