Abstract: Valve prosthesis systems and methods/systems for placement of such valve prostheses are provided that facilitate efficient, reliable and minimally invasive delivery modalities. The placement systems and methods permit remote manipulation and positioning of the valve prosthesis such that desirable placement relative to anatomical structures, e.g., the heart annulus, may be achieved. The valve prosthesis includes a resilient ring, a plurality of leaflet membranes mounted with respect to the resilient ring, and a plurality of positioning elements movably mounted with respect to the flexible ring. The delivery system includes a first elongate element that terminates at the valve prosthesis and is manipulable by an operator to remotely rotate the positioning elements relative to the flexible ring. A second elongate element terminates at the valve prosthesis and is manipulable by an operator to remotely advance the valve prosthesis downward into an anatomical annulus.