The Ross Procedure reassessed

The search for an ideal biological heart valve substitute has been going on for half a century. In 1960 Lower and Shumway1 described the feasibility of replacing the aortic valve in dogs with a native pulmonary valve. In London, Ross had already pioneered the homograft clinically in 19622 but it had become clear that a valve taken from a deceased person would have a limited durability. To use the pulmonary valve which has the same embryological origin as the aortic valve and is a living autologous valve substitute, was a ground breaking idea. In 1967 Ross performed this procedure (on humans)3 and replaced the pulmonary valve with an aortic homograft in a patient predicting that placed in a low pressure, high compliance circuit, the durability of the homograft would be greater than in the systemic circulation. It was reasoned that the pulmonary autograft, although subjected to systemic pressure would, as a living valve, be able to adapt. As it turns out, the aortic valve has several sophisticated features that are dependent on its viability4-6. The different parts of the aortic valve change their size and shape during the cardiac cycle. This property can affect left ventricular workload and possibly coronary flow, together with stress distribution on the valve leaflets. Furthermore, living aortic valve leaflets modify their stiffness in response to humoral and endothelial-derived signals, allowing them to adapt to changes in haemodynamic conditions