Clinical and haemodynamic evaluation of mounted porcine heterograft in mitral position.

Clinical and haemodynamic assessment has been made of 24 patients with porcine hetero- graft mitral valve replacements. Twenty patients had a good clinical result and were studied electively and 4 patients had persistent symptoms caused either by poor left ventricular function, aortic para- prosthetic regurgitation, mitral paraprosthetic regurgitation, or impaired left ventricular function with a rather small mitral valve area of 1-4 cm2. The mean left ventricular end-diastolic pressure was 17-8 1-2 mmHg and the mean mitral valve diastolic gradient was 5 9 1.0 mmHg. The larger prostheses had the smaller gradients. The average mitral valve area was 3-2 cm2 for 35 mm valves, 2-8 cm2 for 33 mm valves, 2-1 cm2 for 31 mm valves, and 2-3 cm2 for 29 mm valves. Two patients showed significant mitral regurgitation on left ventricular cineangiography but in the remainder the valves were competent.