Patent ID: 8021417

Claim:
An implantable medical device that provides a valve for regulating fluid flow through a body vessel, comprising: a support frame; at least one leaflet attached to the support frame 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, one of the at least one leaflet having a leaflet free edge not attached to the support frame, first and second opposing surfaces and defining an opening extending through the one leaflet from the first surface to the second opposing surface that permits a controlled amount of fluid flow in the second, opposite direction to proceed through the opening when the one leaflet is in the second position, the opening spaced from the leaflet free edge on the one leaflet and having an opening first side edge defined by the one leaflet and an opening second side edge defined by the one leaflet and disposed on the one leaflet opposite the opening first side edge; a moveable flap integrally formed with a portion of the one leaflet adjacent the opening first side edge and free of the one leaflet at the opening second side edge, the moveable flap adapted to temporarily and substantially close the opening.