Nistal F, García-Martínez V, Fernández D, Artiñano E, Mazorra F, Gallo I
Departamento de Cirugía Cardiovascular, Hospital Nacional Marqués de Valdecilla, Universidad de Cantabria, Santander, Spain.
J Thorac Cardiovasc Surg. 1988 Oct;96(4):642-51.
Degeneration of bioprosthetic heart valves constitutes the most important limitation to their long-term durability and the factor that avoids a wider clinical use of these devices. We studied 26 degenerated bovine pericardial valves that belong to a series of 55 prostheses explanted for various reasons. Age of the patients at implantation of the valve and other factors predisposing to primary tissue failure did not seem to significantly influence the results obtained. Mean implantation time was longer for aortic than for mitral valves (p less than 0.05). Also, the mode of failure was different for mitral and aortic prostheses. Tearing of one or more leaflets without mineralization was more frequent (p less than 0.0025) among mitral than among aortic specimens. Coverage of the valve cusps by a macroscopically visible host sheath was more extensive on the outflow than on the inflow aspect (p less than 0.0015 aortic valves; p less than 0.015 mitral valves). On radiological examination the majority of valves had diffuse and severe mineralized lesions. Collagen degeneration was the most frequent histologic lesion to be found in both mineralized and calcium-free valves. Calcification was also frequent and appeared as mineral deposits that extended between different collagen planes. Scanning electron microscopy revealed the almost complete lack of "endothelium-like" cover on any of the valves and exposure of the underlying fibrous components of the pericardial tissue in areas subjected to abrasion. Transmission electron microscopy confirmed the collagen degeneration and disclosed electron-dense microparticles (probably mineralized) both in the extracellular space and within degenerated host connective tissue cells.
生物人工心脏瓣膜的退变是其长期耐久性的最重要限制因素，也是阻碍这些装置更广泛临床应用的因素。我们研究了26个退变的牛心包瓣膜，它们属于因各种原因植入的55个假体系列。瓣膜植入时患者的年龄以及其他易导致原发性组织衰竭的因素似乎并未对所获结果产生显著影响。主动脉瓣的平均植入时间比二尖瓣长（p<0.05）。此外，二尖瓣和主动脉瓣假体的失效模式也不同。二尖瓣标本中一个或多个瓣叶无矿化的撕裂比主动脉瓣标本更常见（p<0.0025）。肉眼可见的宿主鞘对瓣膜尖的覆盖在流出道比流入道更广泛（主动脉瓣p<0.0015；二尖瓣p<0.015）。在放射学检查中，大多数瓣膜有弥漫性和严重的矿化病变。胶原退变是在矿化瓣膜和无钙瓣膜中最常见的组织学病变。钙化也很常见，表现为在不同胶原平面之间延伸的矿物质沉积。扫描电子显微镜显示，任何瓣膜上几乎完全没有“内皮样”覆盖物，并且在遭受磨损的区域心包组织的下层纤维成分暴露。透射电子显微镜证实了胶原退变，并在细胞外空间和退变的宿主结缔组织细胞内均发现了电子致密微粒（可能矿化）。
