Lamson T C, Stinebring D R, Deutsch S, Rosenberg G, Tarbell J M
Bioengineering Program, Pennsylvania State University, University Park 16802.
ASAIO Trans. 1991 Jul-Sep;37(3):M351-3.
A technique for real-time in vitro observation of cavitation on a prosthetic heart valve operating in a ventricular assist device under normal physiologic conditions has been developed. Considering the documented observation of cavitation erosion in heart valve components from human explants, and the potential risk of blood damage that cavitation presents, the technique developed in this study may prove useful in the design of prosthetic heart valves and ventricular assist devices. Cavitation of a glycerol blood analog fluid has been documented for a Medtronic/Hall prosthetic heart valve operating in a Penn State Electric Ventricular Assist Device. The ventricular assist device was operated in a mock circulatory system under normal physiologic conditions. The valve was located in the mitral position, with the cavitation occurring on the inlet side after valve closure. Bubble cavitation was seen on the valve occluder face, and vortex cavitation was observed at two locations in the vicinity of the valve occluder and housing. The cavity growth and collapse cycle for these forms of vaporous cavitation was less than 1 msec. Stroboscopic photography and stroboscopic videography with frame grabbing were used to document the cavity life cycle. With beat rate held constant, the cavity duration time was found to decrease with increasing mean venous return pressure.
已开发出一种技术，可在正常生理条件下，对在心室辅助装置中运行的人工心脏瓣膜上的空化现象进行实时体外观察。鉴于已记录到的人体植入物心脏瓣膜部件中空化侵蚀的观察结果，以及空化所带来的血液损伤潜在风险，本研究中开发的技术可能在人工心脏瓣膜和心室辅助装置的设计中证明有用。已记录到在宾夕法尼亚州立大学电动心室辅助装置中运行的美敦力/霍尔人工心脏瓣膜，其甘油血液模拟液出现了空化现象。心室辅助装置在模拟循环系统中于正常生理条件下运行。瓣膜位于二尖瓣位置，空化现象在瓣膜关闭后的入口侧出现。在瓣膜封堵器表面可见气泡空化，在瓣膜封堵器和外壳附近的两个位置观察到涡旋空化。这些形式的蒸汽空化的腔体生长和坍塌周期小于1毫秒。使用频闪摄影和带帧抓取的频闪摄像来记录腔体生命周期。在心率保持恒定的情况下，发现腔体持续时间随平均静脉回流压力的增加而减少。
