Acute dysfunction of Starr-Edwards mitral prostheses.

Four cases of acute dysfunction of Starr-Edwards mitral prostheses are recorded. The patients presented with sudden dysponea 4 to 18 months after apparently successful mitral valve replacement. The prosthetic valve dysfunction was caused by thrombus on the bare metal cage of the prosthesis. No warning thromboembolic phenomena had been recorded. Urgent replacement of the valve resulted in the survival of one patient.