EVALUATION OF BIOPROSTHETIC CARDIAC VALVE FAILURE IN AN ANIMAL MODEL

本课题的目的是建立生物假体的动物模型。 并利用该动物模型系统评价心脏瓣膜功能衰竭 脑血管病的病理改变和血流动力学障碍 价值观。我们已经证明，在青少年患者体内植入生物瓣膜 绵羊表现出相同的病理变化，即退化和 钙化与植入人体的钙化一样；然而， 与人类相比，绵羊的这些变化更快。差一点 500个普鲁因主动脉或牛心包生物假体，从9个 在动物模型系统中植入了不同的来源以评估 病理改变的特点，以比较改变 在不同类型的值中，比较阀门中发生的变化 在二尖瓣和三尖瓣位置植入，并评估 植入前对瓣膜进行处理以延缓或消除 钙化过程。由于这些类型的观察，临床上 一种新型生物假体瓣膜已经开始试验。 同样重要的是，至少有五种类型的阀门 被拒绝考虑用于临床。该模型还增加了 用于验证超声技术，包括颜色编码 2-D多普勒，用于表征生物假体、机械和 合成叶瓣速度/流量分布和非侵入性 检测阀门故障。

The purpose of this project is to develop animal model of bioprosthetic cardiac valve failure and to utilize this animal model system to evaluate the pathologic alterations and hemodynamic dysfunction which develops in the values. We have shown that bioprosthetic valves implanted in juvenile sheep demonstrate the same pathologic alternations of degeneration and calcification as those implanted in humans; however, the development of these alterations is accelerated in sheep as compared to humans. Nearly 500 procine aortic or bovine pericardial bioprosthetic values from nine different sources have been implanted in the animal model system to assess the characteristics of the pathologic changes, to compare the alterations in different types of values, to compare the alterations ocurring in valves implanted in the mitral versus the tricuspid positions, and to evaluate valves treated prior to implantation with processes to retard or eliminate the calcification process. Due to these types of observations, clinical trials have been initiated with one new type of bioprosthetic valve. Equally important, if not more so, at least five types of valves have been rejected from consideration for clinical use. The model is additionally being utilized to validate ultrasonic techniques, including color encoded 2-D Doppler, for the characterization of bioprosthetic, mechanical, and synthetic leaflet valve velocity/flow profiles and for the noninvasive detection of valve failure.