A new design for polyurethane heart valves

Background and aim of fire study: The synthetic flexible tri-leaflet heart valve offers considerable potential for improvement in both hydrodynamic an d biomechanical performance of replacement heart valves. To date, success w ith the synthetic leaflet heart valve has been limited, partly due to limit ations in the biostability of the polyurethanes used. With the synthesis of new biostable polyurethanes, the integration of advancing technology, and better knowledge of the functional and biomechanical design requirements ne cessary to increase the longterm durability of the polyurethane heart valve , novel clinical solutions are now in sight. Methods: This study describes the design characteristics, hydrodynamic and biomechanical performance of a new design of polyurethane heart valve. The function and durability characteristics of this novel design of heart valve , manufactured using a proven durable non-biostable polyurethane, was compa red with that of a single AorTech porcine bioprosthetic heart valve and a s ingle tilting disc mechanical heart valve, the Bjork-Shiley Monostrut valve (BSM), of similar size. Results: For equivalent sizes of valve, the new polyurethane heart valve de sign had significantly lower pressure gradients compared with the porcine v alve at all flow rates and to the BSM valve at the higher flow rates. The e ffective orifice area of the polyurethane valve was greater than the other two valves studied; regurgitation and total energy loss were less. The new polyurethane valve design reached over 360 million cycles in an accelerated durability tester, without failure. Conclusion: This new design of polyurethane heart valve showed improved hyd rodynamic function in comparison with either the porcine bioprosthetic or t he BSM mechanical heart valve. The pulsatile flow results showed a lower to tal energy loss associated with this valve, indicating improved potential p atient benefit. The durability of this new design of polyurethane heart val ve was demonstrated when manufactured using a medical-grade polyurethane.