Lockie K J, Butterfield M, Fisher J, Juster N P, Watterson K, Davies G A
Department of Mechanical Engineering, University of Leeds, United Kingdom.
Ann Thorac Surg. 1993 Jul;56(1):125-30. doi: 10.1016/0003-4975(93)90415-e.
With the increasing interest in aortic homografts as either a free-sewn valve or whole-root replacement, the effect of internal pressure and dilation of the aorta and aortic root on valve leaflet geometry has been studied. Seven aortic homograft roots were studied, six that had been stored in antibiotics and one that had been cryopreserved. The diameter of the aorta was determined as a function of internal pressure and correlated with the stress-strain characteristics of the aortic wall. Three-dimensional leaflet surface geometry was measured in the "neutral" position, and the leaflet was characterized by its radius of curvature and angle of inclination, using a cylindrical model. The diameter of the aorta increased by between 30% and 50% as the dilation pressure increased from 0 to 120 mm Hg. This was consistent with the stress-strain data obtained from strips of the aortic wall in the circumferential direction. The angle of inclination of the leaflet increased from 20 to 80 degrees and the radius of curvature increased from 4 to 17 mm as the internal pressure increased from 0 to 80 mm Hg. The open leaflet configuration showed a triangular orifice with low bending strains for a dilated root, but increased bending strains with reduced dilation pressure. These are important considerations when implanting a free-sewn homograft into the aortic root.
随着人们对主动脉同种异体移植物作为游离缝合瓣膜或全根置换物的兴趣日益增加，已对主动脉及主动脉根部的内压和扩张对瓣叶几何形状的影响进行了研究。研究了七个主动脉同种异体移植根部，六个保存在抗生素中，一个进行了冷冻保存。确定主动脉直径作为内压的函数，并将其与主动脉壁的应力应变特性相关联。在“中性”位置测量瓣叶表面的三维几何形状，并使用圆柱模型通过其曲率半径和倾斜角度来表征瓣叶。当扩张压力从0增加到120 mmHg时，主动脉直径增加了30%至50%。这与从主动脉壁条带在圆周方向上获得的应力应变数据一致。当内压从0增加到80 mmHg时，瓣叶的倾斜角度从20度增加到80度，曲率半径从4毫米增加到17毫米。对于扩张的根部，开放瓣叶构型显示出具有低弯曲应变的三角形孔口，但随着扩张压力降低，弯曲应变增加。在将游离缝合同种异体移植物植入主动脉根部时，这些都是重要的考虑因素。
