牛心包生物瓣远期损坏原因的病理学研究

A PATHOLOGIC STUDY FOR THE CAUSES OF DAMAGE OF BIOLOGICAL PROSTHESES OF HEART VALVES

本文观察15个植入体内一年以上的非感染性损坏的牛心包生物瓣的病理形态改变。见86.7%的瓣叶有撕裂和穿孔。有8.9%的瓣叶有肉眼可见的钙化。电镜观察见瓣叶组成各部均有程度不一的组织变性。瓣叶的撕裂和穿孔多见于瓣叶与支架的交界部。鉴于瓣叶游离缘的中心点均低于瓣架顶端平面,故作者认为瓣叶的损伤与组织变化及瓣叶附着部的应力集中有关。

The pathologic morphology of 15 heart valve prostheses made by bovine pericardium was studied by light and electron microscopy. The durations of valve replacement were 1.9-11.6 years (6.5±1.4). All of the valves showed tears on the free edges of the leaflets or the bases of the cups. The average longth of the tears was 0.3-1.5cm. In one case, a perforation was found in the body of the leaflet. In some cases enlarged holes of sutures in the leaflets could be seen. Calcification was found in 4 cases grossly. The distributions of calcium deposits in 2 cases were diffused and the others were scattered. The centres of the free edges in all valves were lower than those of their attachments. Electron microscopically, degeneration of collagen fibers of various degrces was seen, some degenerated fibers were associated with calcium deposition.The results show that the causes of damage of the prosthesis are related to the degeneration of the leaflets and the mechanical stress during heart contraction. In order to prolong the life of the prosthesis, it is necessary to prevent the tissue from degeneration and design a proper geometrical pattorn of the valve. The structure of the biological material and the techniques in sewing must also be noted.