Hemolytic anemia with porcine xenograft aortic and mitral valves.

Severe hemolytic anemia occurred in a 30-year-old man 12 months after insertion of 23 mm and 31 mm Hancock porcine xenografts in the aortic and mitral positions respectively. At catheterization the mean transvalvular aortic xenograft gradient was 63 mm Hg, and at operation the stents of the aortic xenograft were bent inward, causing a supravalvular secondary orifice obstruction. One year later the patient has only subclinical hemolysis consistent with Björk-Shiley aortic and mitral prostheses.