Monocuspid prosthetic valve having a partial sinus

1. A valve prosthesis for implantation in a body vessel having a vessel wall, said valve prosthesis comprising:

an implantable frame radially-expandable from a compressed configuration to an expanded configuration having an interior lumen, the frame defining a laterally asymmetric partial sinus portion of the interior lumen extending around between about 10% and about 90% of the circumference of the frame in the expanded configuration; and

a valve member;

wherein the frame includes a proximal portion, a distal portion, and an intermediate portion;

the valve member comprising at least one leaflet operatively attached to the frame, the at least one leaflet having a base and a free edge and being movable between a first position to permit fluid flow through said body vessel in a first direction and a second position to form a valve pocket that collects fluid and substantially prevents fluid flow through said body vessel in a second direction that is opposite the first direction;

the partial sinus portion of the interior lumen being defined by a bulge of the intermediate portion in a lateral direction such that the bulge of the intermediate portion has a width greater than the width of the distal portion and the proximal portion;

wherein the at least one leaflet forms a seal with a first portion of said vessel wall opposite the bulge of the intermediate portion of the frame and cooperatively defines the valve pocket with a second portion of said vessel wall of said body vessel adjacent the bulge of the intermediate portion when the at least one leaflet is in the second position.

2. The prosthesis of claim 1 , where the proximal portion and the distal portion have a radial force that is less than the radial force of the intermediate portion.

3. The prosthesis of claim 1 , where the intermediate portion has a longitudinal length at least as great as the longitudinal length of the at least one leaflet.

4. The valve prosthesis of claim 1 , the leaflet free edge defining a valve orifice moveable within the interior lumen to modify fluid flow through the interior lumen by movement of the free edge between an open position permitting fluid flow through the valve orifice and a closed position engaging a portion of the frame opposite the partial sinus portion of the interior lumen to reduce fluid flow through the interior lumen.

5. The valve prosthesis of claim 4 , where in the open position the valve leaflet is at least partially within the partial sinus.

6. The valve prosthesis of claim 1 , where the partial sinus portion extends around between about 25% and about 75% of the circumference of the frame in the expanded configuration.

7. The valve prosthesis of claim 1 , where the partial sinus portion extends around between about 40% and 60% of the circumference of the frame in the expanded configuration.