Implantable medical device with constrained expansion

1. A medical device for implantation in a body vessel, comprising:

a support structure having a first, unexpanded configuration and a second, expanded configuration; and

a graft member connected to the support structure and comprising a valve portion and a constraining portion, the valve portion adapted to permit fluid flow through said vessel in a first direction and substantially prevent fluid flow through said vessel in a second, opposite direction, and the constraining portion comprising a gathered portion of the graft member that includes first and second non-contiguous regions of the graft member held adjacent one another by a connecting mechanism, the constraining portion adapted to substantially prevent the support structure from achieving the second, expanded configuration.

2. The medical device of claim 1 , wherein the gathered portion defines a passageway adapted to permit a controlled amount of fluid flow through said body vessel in the second, opposite direction.

3. The medical device of claim 1 , wherein the graft member comprises an extracellular matrix material.

4. The medical device of claim 1 , wherein the graft member comprises small intestine submucosa.

5. The medical device of claim 1 , wherein the graft member defines an edge substantially free of the support structure, the edge cooperating with a portion of the support structure to define an opening adapted to permit a controlled amount of fluid flow through said body vessel in the second, opposite direction.

6. The medical device of claim 5 , wherein the edge is defined by the constraining portion of the graft member.

7. A medical device for implantation in a body vessel, comprising:

a support structure having a first, unexpanded configuration and a second, expanded configuration; and

a graft member connected to the support structure and comprising a valve portion and a constraining portion, the valve portion adapted to permit fluid flow through said vessel in a first direction and substantially prevent fluid flow through said vessel in a second, opposite direction, and the constraining portion comprising a gathered portion of the graft member and adapted to substantially prevent the support structure from achieving the second, expanded configuration;

wherein the gathered portion defines a passageway adapted to permit a controlled amount of fluid flow through said body vessel in the second, opposite direction; and

further comprising a cannula disposed in the passageway.

8. The medical device of claim 7 , wherein the cannula comprises a distal end disposed near the valve portion of the graft member and a proximal end disposed near the constraining portion of the graft member, and wherein the proximal end defines an opening angulated with respect to the graft member.

9. A medical device for implantation in a body vessel, comprising:

a support structure; and

first and second graft members connected to the support structure, each of the graft members comprising a valve portion and a constraining portion, the valve portions being disposed substantially opposite one another and adapted to cooperatively permit fluid flow through said vessel in a first direction and substantially prevent fluid flow through said vessel in a second, opposite direction;

wherein at least one of the constraining portions comprises a gathered portion of one of the first and second graft members, the gathered portion including first and second non-contiguous regions of the graft member held adjacent one another by a connecting mechanism;

wherein the constraining portions cooperate to substantially prevent the support structure from achieving the second, expanded configuration.

10. The medical device of claim 9 , wherein the gathered portion defines a passageway adapted to permit a controlled amount of fluid flow through said body vessel in the second, opposite direction.

11. The medical device of claim 9 , wherein the graft member comprises an extracellular matrix material.

12. The medical device of claim 9 , wherein the graft member comprises small intestine submucosa.

13. A medical device for implantation in a body vessel, comprising:

a support structure; and

first and second graft members connected to the support structure, each of the graft members comprising a valve portion and a constraining portion, the valve portions being disposed substantially opposite one another and adapted to cooperatively permit fluid flow through said vessel in a first direction and substantially prevent fluid flow through said vessel in a second, opposite direction;

wherein at least one of the constraining portions comprises a gathered portion of one of the first and second graft members;

wherein the constraining portions cooperate to substantially prevent the support structure from achieving the second, expanded configuration;

wherein the gathered portion defines a passageway adapted to permit a controlled amount of fluid flow through said body vessel in the second, opposite direction; and

further comprising a cannula disposed in the passageway.

14. The medical device of claim 13 , wherein the cannula comprises a distal end disposed near the valve portion of the graft member and a proximal end disposed near the constraining portion of the graft member, and wherein the proximal end defines an opening angulated with respect to the graft member.

15. A prosthetic valve for implantation in a body vessel, comprising:

a support structure having a first, unexpanded configuration and a second, expanded configuration;

a first valve leaflet connected to the support structure and comprising a first valve portion and a first constraining portion comprising a gathered portion of the first valve leaflet that includes first and second non-contiguous regions of the first valve leaflet held adjacent one another by a first connecting mechanism; and

a second valve leaflet connected to the support structure and comprising a second valve portion and a second constraining portion comprising a gathered portion of the second valve leaflet that includes third and fourth non-contiguous regions of the second valve leaflet held adjacent one another by a second connecting mechanism;

wherein the first and second valve portions cooperatively regulate fluid flow through said body vessel; and

wherein the first and second constraining portions cooperatively prevent the support structure from achieving the second, expanded configuration.