Abstract: The present invention relates to a prosthetic device for treating venous backflow, wherein the prosthetic device is configured for placement into the junction between right atrium and vena cava inferior of a patient. The prosthetic device comprises an expandable stent frame and a valve element attached to the stent frame as well as an annular positioning assembly coupled to the stent frame and extending outwardly and radially from the exterior area of the stent frame.