Reif T H, Huffstutler M C
Int J Artif Organs. 1984 Sep;7(5):277-82.
The pressure-flow rate characteristics of two new convex-concave pivoting disc prosthetic heart valves are evaluated in vitro. The Omniscience and Björk-Shiley prostheses are chosen since both use curved occluders with similar dynamic function, but with different occluder curvature and eccentricity. The Omniscience prosthesis is shown to have consistently less pressure loss, and therefore less energy loss, over a range of steady state and pulsatile flow rates. The enhanced flow characteristics of the Omniscience valve are attributed to the larger opening angle of the occluder, the method of retaining the occluder, in the valve frame, the smaller curvature of the occluder, the smaller pivot-axis eccentricity, and the smaller profile thickness of the occluder. The valves are also tested in the closed position, with steady state pressure gradients causing leakage or backflow. This data is compared with the pulsatile pressure-flow rate data to gain insight into the nature of regurgitation. The total regurgitation of the pivoting disc valves are thought to be strongly dependent upon both the maximal opening angle of the occluder and the radial clearance between the disc and the valve orifice. Both the Omniscience valve and the Björk-Shiley valve are found to have nearly equal volumes of total regurgitation.
在体外评估了两种新型凸凹枢轴盘式人工心脏瓣膜的压力-流量特性。选择了全知型和 Björk-Shiley 假体，因为它们都使用具有相似动态功能但封堵器曲率和偏心率不同的弯曲封堵器。结果表明，在一系列稳态和脉动流量下，全知型假体的压力损失始终较小，因此能量损失也较小。全知型瓣膜增强的流动特性归因于封堵器的较大开口角度、封堵器在瓣膜框架中的固定方法、封堵器较小的曲率、较小的枢轴轴线偏心率以及封堵器较小的外形厚度。还对瓣膜在关闭位置进行了测试，稳态压力梯度会导致泄漏或回流。将该数据与脉动压力-流量数据进行比较，以深入了解反流的性质。枢轴盘式瓣膜的总反流被认为强烈依赖于封堵器的最大开口角度以及盘与瓣膜孔之间的径向间隙。发现全知型瓣膜和 Björk-Shiley 瓣膜的总反流体积几乎相等。
