Hasenkam J M, Nygaard H, Paulsen P K, Kim W Y, Hansen O K
Department of Thoracic and Cardiovascular Surgery, Skejby Sygehus, Aarhus University Hospital, Denmark.
J Heart Valve Dis. 1994 May;3(3):324-9.
Data on the magnitude of forces which can be generated by the myocardium on a prosthetic heart valve ring are not available from the literature. Therefore, we implanted strain gauge mounted 29 mm original specification Edwards-Duromedics mitral valve prostheses in 13 pigs. The valves were implanted in both anatomic and anti-anatomic orientation. In order to estimate the forces on the valve ring, acute in vivo measurements of the dynamic deformation of the valve ring were performed and correlated with the stiffness of the same valves measured in vitro. In the post cardioplegic heart of the anesthetized pigs there was a maximum force developed by the myocardium of 6-8 N on the valve ring with a resulting maximum deformation of 40 microns with valves mounted in the anatomic position. These findings have implications for design of future mechanical mitral valves and for mitral rings used for mitral valvuloplasty. These data can also be used as reference for evaluation of safety limits in existing valves in terms of their physical properties. Based on the direction of the maximum myocardial force acting on the mitral valve ring and the difference in compliance of the valve ring along the pivotal or orthogonal axis, it is indicated from that these acute porcine studies that bileaflet valves in the mitral position are subjected to less deformation when implanted 60 degrees counter-clockwise to the native mitral intercommisural line.
关于心肌在人工心脏瓣膜环上所产生力的大小的数据，文献中尚无记载。因此，我们在13头猪身上植入了安装有应变仪的29毫米原规格爱德华兹 - 杜罗梅迪克斯二尖瓣假体。瓣膜以解剖学和反解剖学方向植入。为了估算瓣膜环上的力，对瓣膜环的动态变形进行了急性体内测量，并将其与在体外测量的相同瓣膜的刚度相关联。在麻醉猪的心脏停搏后心脏中，当瓣膜以解剖位置植入时，心肌在瓣膜环上产生的最大力为6 - 8牛，导致最大变形为40微米。这些发现对未来机械二尖瓣的设计以及用于二尖瓣成形术的二尖瓣环具有启示意义。这些数据也可作为根据现有瓣膜的物理特性评估其安全极限的参考。基于作用于二尖瓣环的最大心肌力的方向以及瓣膜环沿枢轴或正交轴的顺应性差异，从这些急性猪实验表明，二尖瓣位置的双叶瓣膜在相对于天然二尖瓣瓣间线逆时针60度植入时变形较小。
