Erythrocyte survival in patients with porcine xenograft aortic and mitral valves.

Ten patients with porcine xenograft aortic and mitral valve prostheses were studied three to 36 months (mean 15 months) postoperatively for evidence of hemolysis. Studies included complete blood count, reticulocyte count, red cell indices, percentage of schistocytes on blood smears, bilirubin concentration, lactic dehydrogenase, serum iron, total iron binding capacity, haptoglobin, serum folate and vitamin B12 levels, Coombs' test, methemoglobin reduction test, autologous 51Cr erythrocyte survival, and urinary examination for iron and hemosiderin. All patients were hemodynamically stable. Nine patients had normal valve function and no evidence of hemolysis. One patient with paravalvular aortic regurgitation had mechanical hemolytic anemia with a negative Coombs' test. Porcine valve xenografts do not seem to be associated with hemolysis unless complicated by a paravalvular leak.