Ramasamy N, Chen H, Miller P J, Jassawalla J S, Oyer P E, Portner P M
Novacor Division, Baxter Healthcare Corporation, Oakland, CA 94621.
ASAIO Trans. 1988 Jul-Sep;34(3):696-702.
Both porcine (PX) and bovine pericardial (BP) valves have been used in the implantable Novacor left ventricular assist system (LVAS). Results from 58 chronic LVAS implants of greater than 7 days in calves and adult sheep are presented: the PX valve was used in 41 and the BP in 17. With PX valves, the maximum and mean assist durations were 161 and 54 days, respectively, in the calf and 279 and 129 days, respectively, in the sheep. The maximum and mean durations for BP valves were 93 and 38 days (calf) and 153 and 69 days (sheep). In bovine studies with PX valves, severe obstructive pseudoneointimal (PNI) proliferation in the Dacron inflow conduit was the primary cause for termination; valves exhibited moderate calcification. With BP valves, both PNI proliferation and severe valve calcification contributed to a declining pump output, leading to termination. In contrast to the bovine experience, PNI proliferation was not observed in ovine implants. BP valves still became calcified, as evidenced by a progressive decline in pump output (from about twelve weeks) and confirmed at termination. Valve calcification was minimal with the PX valves, even at 236 days. These results favor the adult ovine animal model for extended implants.
猪心包（PX）瓣膜和牛心包（BP）瓣膜均已用于可植入式诺瓦科尔左心室辅助系统（LVAS）。本文展示了对小牛和成年绵羊进行的58例植入时间超过7天的慢性LVAS植入手术的结果：41例使用了PX瓣膜，17例使用了BP瓣膜。使用PX瓣膜时，小牛的最长辅助时间和平均辅助时间分别为161天和54天，绵羊分别为279天和129天。BP瓣膜的最长和平均使用时间分别为93天和38天（小牛）以及153天和69天（绵羊）。在牛的研究中使用PX瓣膜时，涤纶流入管道中严重的阻塞性假内膜（PNI）增生是导致实验终止的主要原因；瓣膜出现中度钙化。使用BP瓣膜时，PNI增生和严重的瓣膜钙化均导致泵输出量下降，从而导致实验终止。与牛的情况不同，在绵羊植入实验中未观察到PNI增生。BP瓣膜仍会发生钙化，泵输出量逐渐下降（从约12周开始）并在实验终止时得到证实。即使在236天时，PX瓣膜的钙化也很轻微。这些结果表明成年绵羊动物模型更适合进行长期植入实验。
