Severe and early stenosis of porcine heterograft mitral valve.

A patient who had aortic and mitral valves replaced by Carpentier porcine heterografts for bacterial endocarditis developed severe heart failure 18 days after operation. A second emergency operation revealed that the mitral prosthesis had become severely stenosed and calcified. A loud Graham Steell murmur had developed during the 12 hours before reoperation but no distinct murmurs of mitral stenosis had been detected.