Kunzelman K S, Grande K J, David T E, Cochran R P, Verrier E D
Division of Cardiothoracic Surgery, University of Washington, Seattle 98195.
J Thorac Cardiovasc Surg. 1994 Jan;107(1):162-70.
A surgical procedure has recently been described for patients with aortic incompetence caused by annular dilation, but with normal aortic leaflets. The dilated aortic root is replaced with a Dacron graft, and the native aortic valve is resuspended within the graft. Matching the size and shape of the graft to the size of the leaflets may have significant effects on valve closure and leaflet stress and thus on the longevity of the repair. To define the relationship of native aortic root structure to leaflet size, we morphologically examined normal human aortic roots (n = 10) and valve leaflets and applied mathematic analyses to the results. Our data show that the root has a consistent shape with varying size and that there is a definable mathematic relationship between root diameter and clinically measurable leaflet dimensions. We derived an equation that allows calculation of the appropriate diameter of the root at the sinus of Valsalva level from leaflet heights and perimeters. The diameter of the graft at the sinotubular junction and base should follow the relationship of the normalized root dimensions, either by tailoring of the graft or by new graft design. The current data imply that the graft should incorporate sinuses for proper valve closure and for sharing stress with the leaflets. Application of these results will allow prosthetic graft design to more closely resemble the native aorta. These new grafts should improve physiologic function of the valve, reduce leaflet stress, and increase the durability of the repair.
最近有人描述了一种针对因瓣环扩张但主动脉瓣叶正常而导致主动脉瓣关闭不全患者的外科手术方法。用涤纶人工血管替换扩张的主动脉根部，并将天然主动脉瓣重新悬吊于人工血管内。使人工血管的大小和形状与瓣叶大小相匹配，可能会对瓣膜关闭和瓣叶应力产生重大影响，进而影响修复的持久性。为了确定天然主动脉根部结构与瓣叶大小之间的关系，我们对正常人类主动脉根部（n = 10）和瓣膜瓣叶进行了形态学检查，并对结果进行了数学分析。我们的数据表明，主动脉根部形状一致但大小各异，并且根部直径与临床上可测量的瓣叶尺寸之间存在可确定的数学关系。我们推导出了一个方程，可根据瓣叶高度和周长计算出在主动脉瓣窦水平处根部的合适直径。在窦管交界处和基部的人工血管直径应遵循标准化根部尺寸的关系，可通过裁剪人工血管或设计新的人工血管来实现。目前的数据表明，人工血管应包含窦部，以实现瓣膜的正常关闭并与瓣叶分担应力。应用这些结果将使人工血管的设计更接近天然主动脉。这些新型人工血管应能改善瓣膜的生理功能，减轻瓣叶应力，并提高修复的耐久性。
