Lee Hwansung, Tatsumi Eisuke, Homma Akihiko, Tsukiya Tomonori, Taenaka Yoshiyuki
Department of Artificial Organs, The Advanced Medical Engineering Center, Research Institute, National Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
J Artif Organs. 2006;9(3):154-60. doi: 10.1007/s10047-006-0332-5.
It is possible that mechanical heart valves mounted in an artificial heart close much faster than those used for clinical valve replacement, resulting in the formation of cavitation bubbles. In this study, the mechanism for mechanical heart cavitation was investigated using the Medtronic Hall monoleaflet valve and the Sorin Bicarbon bileaflet valve mounted at the mitral position in an electrohydraulic total artificial heart. The valve-closing velocity was measured with a charge-coupled device (CCD) laser displacement sensor, and images of mechanical heart valve cavitation were recorded using a high-speed video camera. The valve-closing velocity of the Sorin Bicarbon bileaflet valve was lower than that of the Medtronic Hall monoleaflet valve. Most of the cavitation bubbles generated by the monoleaflet valve were observed near the valve stop; with the Sorin Bicarbon bileaflet valve, cavitation bubbles were concentrated along the leaflet tip. The cavitation density increased as the valve-closing velocity and the valve stop area increased. These results strongly indicate that squeeze flow holds the key to cavitation in the mechanical heart valve. From the perspective of squeeze flow, bileaflet valves with a low valve-closing velocity and a small valve stop area may cause less blood cell damage than monoleaflet valves.
植入人工心脏的机械心脏瓣膜关闭速度可能比用于临床瓣膜置换的瓣膜快得多，从而导致空化气泡的形成。在本研究中，使用美敦力霍尔单叶瓣膜和索林双叶瓣膜，将其安装在电动液压全人工心脏的二尖瓣位置，研究机械心脏空化的机制。用电荷耦合器件（CCD）激光位移传感器测量瓣膜关闭速度，并用高速摄像机记录机械心脏瓣膜空化的图像。索林双叶瓣膜的瓣膜关闭速度低于美敦力霍尔单叶瓣膜。单叶瓣膜产生的大部分空化气泡在瓣膜止动附近观察到；对于索林双叶瓣膜，空化气泡集中在瓣叶尖端。空化密度随着瓣膜关闭速度和瓣膜止动面积的增加而增加。这些结果有力地表明，挤压流是机械心脏瓣膜空化的关键。从挤压流的角度来看，瓣膜关闭速度低且瓣膜止动面积小的双叶瓣膜可能比单叶瓣膜对血细胞的损伤更小。
