Pulmonary Autograft and Ross Procedure : Sir Donald Ross in 1967 introduced the concept of using patient's own pulmonary valve (autograft) for aortic valve replacement and a pulmonary allograft to replace the excised pulmonary valve. This cryopreservetl pulmonary allograft does not deteriorate in the low-pressure pulmonary circulation. The pulmonary autograft in aortic position has functioned well over a long period of follow-up.