A heart valve prostheses includes an annular member implantable within a biological annulus, a collar extending upwardly from the annular member, and a sewing ring extending from the annular member. A spring structure couples the collar to the annular member and biases the collar to align with the annular...http://www.google.com/patents/US20070179604?utm_source=gb-gplus-sharePatent US20070179604 - GASKET WITH SPRING COLLAR FOR PROSTHETIC HEART VALVES AND METHODS FOR MAKING AND USING THEM
