Abstract
Intravascular haemolysis was studied in 24 patients three to nine months after calf or pig valve heterografts had been inserted for severe valvular heart disease. No patient had haemolytic anaemia. In five of the 24 patients there was subclinical haemolysis, and in these five the haemolysis appeared to be related to residual aortic regurgitation or to the presence of other foreign material such as a Dacron aortic graft. The extent of postoperative haemolysis in these five patients was comparable to that observed preoperatively in patients with valvular heart disease.The results support the belief that, in contrast to artificial valve prostheses, heterograft valves behave similarly to human valves as regards haemolysis.