Lee Hwansung, Tsukiya Tomonori, Homma Akihiko, Taenaka Yoshiyuki, Tatsumi Eisuke, Takano Hisateru
Department of Biomedical Engineering, Korea University, Medical Center, Seoul, Korea.
Artif Organs. 2003 Aug;27(8):744-8. doi: 10.1046/j.1525-1594.2003.06981.x.
When cavitation occurs near a material surface of a mechanical heart valve (MHV), pits on the surface of the MHV and hemolysis are caused. Therefore, it is very important to investigate the possibility of the occurrence of cavitation in an MHV. To study the possibility of cavitation occurrence in a 25 mm Björk-Shiley monoleaflet, we analyzed the closing behavior of these valves. The closing event of these valves in the mitral and aortic positions was simulated in an electrohydraulic total artificial heart with a stroke volume of 100 ml. Tests were conducted under physiologic pressures at heart rates of 50, 60, 70, and 80 beats/min with cardiac outputs of 4.8, 5.9, 7.0, and 8.1 l/min, respectively. The disk-closing behavior was measured by a laser displacement sensor. The closing behaviors were investigated with various cardiac outputs and gravity direction. The maximum velocities of the aortic valve ranged from 0.8 to 0.9 m/s, and for the mitral valve ranged from 1.48 to 1.6 m/s. In aortic position valves, the maximum closing velocities were less than the reported cavitation thresholds, but the maximum closing velocities of the mitral valve were similar to the cavitation threshold. Therefore, we suggest that there should be the possibility of cavitation occurrence in the mitral valve of an electrohydraulic total artificial heart.
当机械心脏瓣膜（MHV）的材料表面附近发生空化时，会导致MHV表面出现凹坑并引起溶血。因此，研究MHV中发生空化的可能性非常重要。为了研究25毫米Björk-Shiley单叶瓣膜发生空化的可能性，我们分析了这些瓣膜的关闭行为。在 stroke volume为100毫升的电动液压全人工心脏中模拟了这些瓣膜在二尖瓣和主动脉瓣位置的关闭情况。在生理压力下，分别以50、60、70和80次/分钟的心率进行测试，心输出量分别为4.8、5.9、7.0和8.1升/分钟。通过激光位移传感器测量圆盘关闭行为。研究了不同心输出量和重力方向下的关闭行为。主动脉瓣的最大速度范围为0.8至0.9米/秒，二尖瓣的最大速度范围为1.48至1.6米/秒。在主动脉瓣位置的瓣膜中，最大关闭速度低于报道的空化阈值，但二尖瓣的最大关闭速度与空化阈值相似。因此，我们认为电动液压全人工心脏的二尖瓣中应该存在发生空化的可能性。
