The perennial quest for an ideal prosthetic valve

The first surgical heart valve replacement was undertaken over half a century ago since when there has been a continuing quest to develop a prosthesis with the perfect combination of durability, haematological compatibility and haemodynamic performance. Early caged ball mechanical valves were robust but associated with red cell trauma and rapidly followed by introduction of mono-leaflet and bi-leaflet designs which remain in use today. Introduced later in the 1960s, bioprosthetic valves consisting of pericardial or valve tissue mounted on a frame and sewing ring were initially conceived for use in elderly patients unlikely to outlive the valve, or in other patients at risk of bleeding complications associated with anticoagulation. Until recently, mechanical valves have remained the logical choice in patients <65 years of age given the minimal rates of primary valve failure.1 However, advances in the longevity and haemodynamic performance of modern bioprostheses and the emerging potential for transcatheter treatment when they degenerate seem set to challenge this paradigm.2 Stentless bioprosthetic valves offer the potential for (A) further improvements in the flow dynamics of cardiac output and consequent haemodynamic performance, (B) remodelling and dynamic adaptation to the anatomy of the aortic root with resulting progressive increase in the effective orifice area, and (C) enhanced regression of left ventricular hypertrophy with …