Yu A A, White J A, Hwang N H
Department of Biomedical Engineering, University of Miami, Coral Gables, Florida 33124, USA.
ASAIO J. 1998 Sep-Oct;44(5):M475-9. doi: 10.1097/00002480-199809000-00031.
A series of transient pressure signals (TPSs) can be measured using a miniature pressure transducer mounted near the tip of the inflow side of a mechanical heart valve (MHV) occluder during closure. A relationship appears to exist between the intensity and pattern of the TPS and the cavitation potential of a MHV. To study the relationship between MHV cavitation and the TPSs, we installed an MHV in a valve testing chamber of a digitally controlled burst test loop. A charge coupled device (CCD) camera and a personal computer based image grabbing program was used to visualize cavitation bubbles appearing on or near the occluder surface. One bileaflet MHV was used as the model for this study. Cavitation bubbles were observed within 300 microsec of the leaflet/housing impact. The valve was tested at various driving pressures between 100 and 1,300 mmHg. MHV cavitation bubble intensities were qualitatively classified into three categories: 1) strong, 2) weak, and 3) none. Digital images of the MHV occluder inflow surface were recorded simultaneously with the TPSs. TPSs were studied by the time-frequency analysis method (spectrogram) and correlated to MHV cavitation potential. The intensity of the cavitation bubbles was found to be associated with burst test loop driving pressures during leaflet closure.
在机械心脏瓣膜（MHV）封堵器流入侧尖端附近安装一个微型压力传感器，在其关闭过程中可以测量一系列瞬态压力信号（TPS）。TPS的强度和模式与MHV的空化潜力之间似乎存在某种关系。为了研究MHV空化与TPS之间的关系，我们在数控爆破试验回路的瓣膜测试腔中安装了一个MHV。使用电荷耦合器件（CCD）相机和基于个人计算机的图像采集程序来观察封堵器表面或其附近出现的空化气泡。本研究使用了一个双叶MHV作为模型。在瓣叶/外壳碰撞后300微秒内观察到了空化气泡。在100至1300 mmHg的不同驱动压力下对瓣膜进行了测试。MHV空化气泡强度定性分为三类：1）强，2）弱，3）无。在记录TPS的同时，记录了MHV封堵器流入表面的数字图像。通过时频分析方法（频谱图）研究TPS，并将其与MHV空化潜力相关联。发现空化气泡的强度与瓣叶关闭期间爆破试验回路的驱动压力有关。
