Prosthetic valve that permits retrograde flow

1. An implantable medical device that provides a valve for regulating fluid flow through a body vessel, comprising:

a support frame having radially compressed and radially expanded configurations; and

at least one leaflet at least partially defining a valve orifice that regulates said fluid flow, the at least one leaflet having first and second edges and being moveable between a first position that permits said fluid flow in a first direction and a second position that substantially prevents said fluid flow in a second, opposite direction, the first edge attached to the support frame and the second edge being free of the support frame;

wherein a portion of the support frame and the second edge of the at least one leaflet cooperatively define an opening that permits a controlled amount of fluid flow to pass through said medical device in the second, opposite direction, the opening having a size that remains substantially fixed in the first and second positions of the at least one leaflet and being spaced from the valve orifice along an axis of said implantable medical device.

2. The implantable medical device according to claim 1 , wherein the support frame is a self-expandable support frame.

3. The implantable medical device according to claim 2 , wherein the support frame is formed of a nickel-titanium alloy.

4. The implantable medical device according to claim 1 , wherein the at least one leaflet is formed of a bioremodellable material.

5. The implantable medical device according to claim 4 , wherein the bioremodellable material comprises an extracellular matrix material.

6. The implantable medical device according to claim 4 , wherein the bioremodellable material comprises small intestine submucosa.

7. The implantable medical device according to claim 1 , wherein the opening has a total open area; and

wherein the total open area of the opening is sized to be less than the cross-sectional area of said body vessel at a desired point of treatment in said body vessel.

8. The implantable medical device according to claim 1 , wherein the opening has a total open area; and

wherein the total open area of the opening is sized to be less than about 50% of the cross-sectional area of said body vessel at a desired point of treatment in said body vessel.

9. The implantable medical device according to claim 1 , wherein the opening has a total open area; and

wherein the total open area of the opening is sized to be less than about 25% of the cross-sectional area of said body vessel at a desired point of treatment.

10. An implantable medical device that provides a valve for regulating fluid flow through a body vessel, comprising:

a support frame having radially compressed and radially expanded configurations; and

at least one leaflet at least partially defining a valve orifice that regulates said fluid flow, the at least one leaflet having first and second edges and being moveable between a first position that permits said fluid flow in a first direction and a second position that substantially prevents said fluid flow in a second, opposite direction, the first edge attached to the support frame and the second edge being free of the support frame;

wherein a portion of the support frame and the second edge of the at least one leaflet cooperatively define an opening that permits a controlled amount of fluid flow to pass through said medical device in the second, opposite direction, the opening being spaced from the valve orifice along an axis of said implantable medical device; and

at least one suture attaching the first edge of the at least one leaflet to the support frame.

11. An implantable medical device that provides a valve for regulating fluid flow through a body vessel, comprising:

a support frame having radially compressed and radially expanded configurations; and

at least one leaflet at least partially defining a valve orifice that regulates said fluid flow, the at least one leaflet having first and second edges and being moveable between a first position that permits said fluid flow in a first direction and a second position that substantially prevents said fluid flow in a second, opposite direction, the first edge attached to the support frame and the second edge being free of the support frame;

wherein a portion of the support frame and the second edge of the at least one leaflet cooperatively define an opening that permits a controlled amount of fluid flow to pass through said medical device in the second, opposite direction, the opening being spaced from the valve orifice along an axis of said implantable medical device; and

wherein the at least one leaflet comprises first and second leaflets.