Butterfield M, Wheatley D J, Williams D F, Fisher J
Medical and Biological Engineering, School of Mechanical Engineering, The University of Leeds, UK.
J Heart Valve Dis. 2001 Jan;10(1):105-10.
The synthetic flexible tri-leaflet heart valve offers considerable potential for improvement in both hydrodynamic and biomechanical performance of replacement heart valves. To date, success with the synthetic leaflet heart valve has been limited, partly due to limitations 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 necessary to increase the long-term durability of the polyurethane heart valve, novel clinical solutions are now in sight.
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 compared with that of a single AorTech porcine bioprosthetic heart valve and a single tilting disc mechanical heart valve, the Björk-Shiley Monostrut valve (BSM), of similar size.
For equivalent sizes of valve, the new polyurethane heart valve design had significantly lower pressure gradients compared with the porcine valve at all flow rates and to the BSM valve at the higher flow rates. The effective 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.
This new design of polyurethane heart valve showed improved hydrodynamic function in comparison with either the porcine bioprosthetic or the BSM mechanical heart valve. The pulsatile flow results showed a lower total energy loss associated with this valve, indicating improved potential patient benefit. The durability of this new design of polyurethane heart valve was demonstrated when manufactured using a medical-grade polyurethane.
合成柔性三叶心脏瓣膜在改善置换心脏瓣膜的流体动力学和生物力学性能方面具有巨大潜力。迄今为止，合成瓣叶心脏瓣膜的成功应用有限，部分原因在于所用聚氨酯的生物稳定性存在局限。随着新型生物稳定聚氨酯的合成、先进技术的整合以及对提高聚氨酯心脏瓣膜长期耐久性所需功能和生物力学设计要求的更深入了解，新的临床解决方案已初见端倪。
本研究描述了一种新型聚氨酯心脏瓣膜的设计特点、流体动力学和生物力学性能。将这种采用经证实耐用但非生物稳定的聚氨酯制造的新型心脏瓣膜的功能和耐久性特点，与一个尺寸相似的AorTech猪生物心脏瓣膜和一个Björk-Shiley Monostrut瓣（BSM）单叶倾斜碟片机械心脏瓣膜进行了比较。
对于同等尺寸的瓣膜，新型聚氨酯心脏瓣膜设计在所有流速下与猪瓣膜相比，以及在较高流速下与BSM瓣膜相比，压力梯度均显著更低。聚氨酯瓣膜的有效瓣口面积大于所研究的其他两种瓣膜；反流和总能量损失更少。新型聚氨酯瓣膜设计在加速耐久性测试中达到了超过3.6亿次循环且无故障。
与猪生物心脏瓣膜或BSM机械心脏瓣膜相比，这种新型聚氨酯心脏瓣膜设计显示出改善的流体动力学功能。脉动流结果表明该瓣膜的总能量损失更低，表明对患者的潜在益处有所改善。当使用医用级聚氨酯制造时，这种新型聚氨酯心脏瓣膜设计的耐久性得到了证明。
