An implantable valve prosthesis including a frame defining a lumen extending between a proximal frame end and a distal frame end and a leaflet positioned within the lumen and having a distal edge attached to the frame and a proximal edge free of the frame. The leaflet includes a first and a second slit extending distally from the proximal edge and defining a free portion of the leaflet between the first and second slits. The leaflet is movable between a position that allows fluid flow in an antegrade direction and a second position that restricts flow in a retrograde direction.
