Sabbah H N, Stein P D
J Biomech Eng. 1980 May;102(2):147-50. doi: 10.1115/1.3138211.
The maximal extent of disk opening of the Lillehei-Kaster and Björk-Shiley aortic disk prosthetic valves was evaluated in vitro in relation to the characteristics of flow across the valve and valve orientation within the test section. The maximal opening angle of the disk of both types of prostheses was related to the mean systolic ejection rate, cardiac output, and maximal instantaneous aortic flow. Full opening of all valves occurred throughout the entire hydrodynamic range tested when the orientation of the valve was such that the disk opened in the direction of gravitational forces. However, when the valve was oriented to open against the direction of gravitational forces, less than full opening was observed at low flow rates. At such low rates of flow, the extent of opening was also dependent upon valve size. These studies indicate that full opening of the Lillehei-Kaster and Björk-Shiley disk valves appears to be affected by the orientation of the valve relative to gravitational forces. When less than full opening occurs, it is associated with abnormally low mean systolic ejection rates and low levels of cardiac output and aortic flow. Therefore, irrespective of valve orientation, less than maximal opening with normal flow may indicate a mechanical impediment to opening.
在体外评估了利勒黑 - 卡斯特（Lillehei-Kaster）和比约克 - 希利（Björk-Shiley）主动脉瓣盘式人工瓣膜的最大开口程度，该评估与瓣膜内的血流特性以及测试段内瓣膜的方向有关。两种类型假体瓣膜盘的最大开口角度与平均收缩期射血率、心输出量和最大瞬时主动脉血流有关。当瓣膜的方向使得瓣盘朝着重力方向打开时，在整个测试的流体动力学范围内，所有瓣膜均能完全打开。然而，当瓣膜定向为逆着重力方向打开时，在低流速下观察到瓣盘未完全打开。在如此低的流速下，开口程度还取决于瓣膜尺寸。这些研究表明，利勒黑 - 卡斯特和比约克 - 希利瓣盘式瓣膜的完全打开似乎受瓣膜相对于重力方向的影响。当瓣盘未完全打开时，与异常低的平均收缩期射血率以及低的心输出量和主动脉血流水平相关。因此，无论瓣膜方向如何，在正常血流情况下未达到最大开口可能表明存在机械性的开口阻碍。
