Ferrans V J, Milei J, Ishihara T, Storino R
Pathology Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Eur J Cardiothorac Surg. 1991;5(3):144-54. doi: 10.1016/1010-7940(91)90213-4.
Histological, scanning and transmission electron microscope studies were made of normal human dura mater and cardiac valvular bioprostheses made of glycerol-treated human dura mater recovered after having been implanted in the aortic position (8 patients) or the mitral position (1 patient) for periods up to 4 years. Human dura mater has two layers: an inner or meningeal layer and an outer or endosteal layer. The surface of the inner layer is smoother than that of the outer layer. Both layers are composed mainly of large, wavy collagen fibrils (which are thought to correspond to type I collagen) and are relatively poor in elastic fibers and proteoglycans. Small calcific deposits were found in normal dura from older patients. Changes occurring in dura mater bioprostheses within 2 days after implantation consisted mainly of small surface thrombi. Calcific nodules, degenerated collagen and evidence of penetration of erythrocytes and plasma proteins into the cusps were observed in bioprostheses that had failed after being in place for 1-4 years. The calcific deposits and the degenerated collagen appeared structurally similar to those in glutaraldehyde-treated porcine aortic valvular bioprostheses. However, collagen fibrils in the latter were smaller than those in dura mater. Platelet aggregates on the cuspal surfaces were much less numerous in dura mater bioprostheses than in porcine aortic valvular bioprostheses. It is postulated that this difference is a function of the size of the collagen fibrils in the bioprostheses and that this accounts for the very low incidence of clinically evident thromboembolism in patients with implanted dura mater valves.
对正常人类硬脑膜以及由甘油处理过的人类硬脑膜制成的心脏瓣膜生物假体进行了组织学、扫描电子显微镜和透射电子显微镜研究。这些生物假体曾植入主动脉位置（8例患者）或二尖瓣位置（1例患者）长达4年，之后被回收。人类硬脑膜有两层：内层或脑膜层和外层或骨内膜层。内层表面比外层表面更光滑。两层主要由粗大、波浪状的胶原纤维（被认为对应于I型胶原）组成，弹性纤维和蛋白聚糖相对较少。在老年患者的正常硬脑膜中发现了小的钙化沉积。植入后2天内硬脑膜生物假体发生的变化主要是小的表面血栓。在放置1 - 4年后失效的生物假体中观察到钙化结节、变性胶原以及红细胞和血浆蛋白渗入瓣叶的迹象。钙化沉积和变性胶原在结构上与戊二醛处理过的猪主动脉瓣膜生物假体中的相似。然而，后者中的胶原纤维比硬脑膜中的小。硬脑膜生物假体瓣叶表面的血小板聚类比猪主动脉瓣膜生物假体中的少得多。据推测，这种差异是生物假体中胶原纤维大小的作用，这解释了植入硬脑膜瓣膜的患者临床上明显血栓栓塞发生率极低的原因。
