Orthotopic and heterotopic implantation of cryopreserved semilunar valves in the pulmonary circulation

Cryopreserved allografts were introduced in October 1986 at the German Heart Institute Berlin (19). Ever since, aortic and pulmonary homografts have been used for reconstruction of the right ventricular outflow tract in patients with obstructive lesions (1, 2, 5, 8, 9, 12, 16, 19, 21, 22). It was our aim to evaluate the durability of the two different valves in orthotopic and heterotopic positions and to establish the determinant factors for long-term valve performance by site of implantation, age of recipients and conduit size particularly in children.