Dahm M, Prüfer D, Mayer E, Groh E, Choi Y H, Oelert H
Department of Cardiothoracic and Vascular Surgery, University Hospital Mainz, Germany.
J Heart Valve Dis. 1998 Jan;7(1):30-3.
The risk of reoperation due to calcific degeneration is the most important drawback of biological heart valves compared with mechanical prostheses. Concepts to mitigate calcification have been tested experimentally and clinically, but none has proven completely to prevent degeneration.
Renewed interest has involved the use of autologous pericardium for intraoperative construction of autologous aortic valves (ATCV).
Of 10 ATCV implanted between 1994 and 1996, one was removed from an 84-year-old female 27 months after implantation because of severe valvular insufficiency. Eight months earlier, a broken spring of the stent system was detected radiographically, with normal valvular competence at echocardiography. Valve dysfunction was due to shrinkage of one leaflet. Measurement of tissue calcium by atomic absorption spectroscopy showed high levels in the shrunken leaflet compared with two intact leaflets (42.82 versus 0.51 and 2.42 mg Ca2+/g). Histology and immunohistology demonstrated extensive fiber degeneration without inflammation or immune reactions in the destroyed leaflet, and moderate fiber degeneration in intact leaflets. Scanning electron microscopy showed smooth surfaces in the normal leaflet and exposure of collagen in the degenerated leaflet in association with calcium deposition.
In contrast to the outcome in animal studies, intraoperative tanning did not prevent tissue shrinkage in this case. Leaflet malfunction was associated with calcification. At present, the clinical use of valves constructed from autologous pericardium can not be recommended.
与机械瓣膜相比，生物心脏瓣膜因钙化退变而需要再次手术的风险是其最重要的缺点。减轻钙化的方法已在实验和临床中进行了测试，但尚无一种方法被证明能完全防止退变。
人们重新关注使用自体心包在术中构建自体主动脉瓣膜（ATCV）。
在1994年至1996年间植入的10个ATCV中，有一个在植入27个月后从一名84岁女性体内取出，原因是严重的瓣膜功能不全。8个月前，通过放射学检查发现支架系统的一个弹簧断裂，而超声心动图显示瓣膜功能正常。瓣膜功能障碍是由于一个瓣叶收缩所致。通过原子吸收光谱法测量组织钙含量显示，与两个完整瓣叶相比，收缩瓣叶中的钙含量较高（分别为42.82、0.51和2.42mg Ca2+/g）。组织学和免疫组织学显示，受损瓣叶中有广泛的纤维退变，无炎症或免疫反应，而完整瓣叶中有中度纤维退变。扫描电子显微镜显示，正常瓣叶表面光滑，退变瓣叶中胶原暴露并伴有钙沉积。
与动物研究结果不同，在本病例中，术中鞣制未能防止组织收缩。瓣叶功能障碍与钙化有关。目前，不建议临床使用由自体心包构建的瓣膜。
