目的:本研究的目的是开发一种新型的单打开和关闭脉动流体外瓣膜测试仪,用于直接测量心脏瓣膜的关闭量。
方法:单开关阀测试仪由活塞泵组成,阀门安装室,水库,测控系统。活塞泵用于驱动阀门以规定的流量打开和关闭,该流量包括三个加速阶段,常数,并以六个斜坡减速流动。使用高速照相机来记录阀打开和关闭图像。使用两个压力传感器穿过测试的阀门来捕获阀门关闭的结束时间,这已通过高速摄影进行了验证。测量关闭时间并利用阀关闭期间的活塞位移容积计算关闭容积。测试了倾斜盘式瓣膜和猪二尖瓣。
结果:跨音速流量计和活塞泵之间的流量差异很大。心脏瓣膜在活塞泵驱动的规定流量下打开和关闭。跨瓣压力在阀打开期间较小,然后在阀关闭期间急剧增加。关闭时间随减速流量的斜率近似线性变化,并且通过跨瓣膜压力和高速摄影在两种方法之间具有可比性。倾斜盘瓣和二尖瓣的关闭容积随减速流量的斜率变化不大,分别为7.0±1.0和14.0±1.5mL,分别。
结论:脉动流量对流量计具有挑战性。已成功开发出一种新型的用于心脏瓣膜的单打开和关闭脉动流体外瓣膜测试仪,可用于模拟和评估心脏瓣膜的打开和关闭血液动力学。该测试仪可用于测量阀门关闭的体积和时间准确与一个标准化的测试协议,不受影响的其他组件,如电阻,连续脉动流量阀测试仪中的合规单元和辅助阀。
OBJECTIVE: The objective of this study was to develop a novel single opening&closing pulsatile flow in-vitro valve tester for direct measurement of closing volume of the heart valve.
METHODS: A single opening&closing valve tester was composed of a piston pump, valve mounting chamber, reservoir, measurement and control system. The piston pump was used to drive a valve to open and close with dictated flow which comprised three phases of accelerated, constant, and decelerated flow with six slopes. A high speed camera was used to record valve opening and closing images. Two pressure transducers across the tested valve were used to capture the ending time of valve closing which was verified by the high-speed photography. The closing time was measured and closing volume was calculated with a piston displacement volume during valve closing. A tilting disc valve and porcine mitral valve were tested.
RESULTS: There was a big difference in flowrate between the Transonic flowmeter and piston pump. The heart valve opened and closed under the dictated flow driven by the piston pump. The transvalvular pressure was minor during valve opening and then increased sharply during valve closing. The closing time varied approximately linearly with the slope of the decelerated flow and was comparable between the two methods by the transvalvular pressure and high-speed photography. The closing volumes did not change much with the slope of the decelerated flow and were 7.0 ± 1.0 and 14.0 ± 1.5 mL for the tilting disc valve and mitral valve, respectively.
CONCLUSIONS: Pulsatile flow is challenging to the flowmeter. A novel single opening&closing pulsatile flow in-vitro valve tester for the heart valve has successfully been developed and can be used to simulate and evaluate the opening and closing hemodynamics of the heart valve. The tester can be used to measure valve closing volume and time accurately with a standardized testing protocol free from effect of other components such as the resistance, compliance units and auxiliary valve in the continuous pulsatile flow valve tester.