The Ross Procedure reassessed

Abstract

RationaleThe search for an ideal biological heart valve substitute has been going on for half a century. In 1960 lower and shumway 1 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 1962 2 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 viability [4][5][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 5 . Early Results of the Ross ProcedureIn the year 2000, David and colleagues 7 reported that the pulmonary autograft dilated and that the dilation was often accompanied by aortic regurgitation due to outward displacement of the three commissures. David compared the results of the free standing autograft root to the aortic root inclusion technique. several other authors confirmed the findings of early dilatation in the free-standing neo-aortic root 8,9 . as this problem became widely known, fewer surgeons continued to perform the operation, but sievers 10 re-examined the problem and adapted the original sub-coronary technique with some minor changes and demonstrated excellent valve function and lack of dilation of an aortic root at medium term follow up of 7-8 years 11 .In 2009 Takkenberg 12 undertook a meticulous, systematic review and meta-analysis of all publications on the Ross procedure in the preceding 8 years. 39 studies were selected which contained information on early mortality and long term outcomes such as late deaths and re-operations. The authors controlled heterogeneity caused by age by dividing the population into three categories: consecutive series in children and adults, adult patients, and a paediatric series. Early mortality and linearised rates of post operative adverse events were calculated for each study and pooled on a logarithmic scale using the inverse variant method in a fixed effects model. some of the series included were quite small containing only 31 patients. as David has pointed out 13 series such as these will inc...