Pomposelli F, Schoen F, Cohen R, O'Leary D, Johnson W R, Madras P N
J Vasc Surg. 1984 Jul;1(4):525-35.
Late failure of synthetic vascular grafts to small-diameter arteries (less than or equal to 4 mm) is commonly due to anastomotic hyperplasia. Theoretic analysis suggests that conformational changes at the anastomosis lead to high localized arterial wall stress caused by increases in radius of curvature of the artery (law of Laplace: tension = pressure X radius). Nine 3 kg rabbits had a plastic insert implanted into the infrarenal aorta. The insert was designed to recreate the conformational changes caused by the anastomosis of a synthetic graft to a small-diameter artery, without significantly altering blood flow. The increase in arterial wall tension created by the insert was calculated to be 80% to 100% over baseline values. Aortography, real-time ultrasound, and computed tomography (CT) scanning were done to confirm the absence of luminal thrombus formation or migration of the insert. Ultrasound and CT scans also confirmed the desired conformational changes in the aorta at the site of the insert. Aortas, with the inserts in place, were removed from 3 days to 6 months after implantation. Implantation times of 1 to 6 months resulted in a hyperplastic subintimal lesion characterized by fibrous tissue deposition, spindle cells (which may have been fibroblasts), and/or smooth muscle cells covered by endothelium. In contrast, two rabbits that had the insert placed and then removed at 1 minute and were allowed to survive for 37 and 72 days, respectively, demonstrated complete healing of the aorta without anastomotic hyperplasia. The arterial wall conformational changes induced in this experiment led to the formation of a lesion consistent with anastomotic hyperplasia. An increase in wall tension may have been the stimulus for this response. Prevention of anastomotic hyperplasia may require a means of uniting a graft to an artery without increasing wall tension.
人工血管移植至小口径动脉（直径小于或等于4毫米）后的晚期失败通常归因于吻合口增生。理论分析表明，吻合口处的构象变化会导致动脉壁局部应力升高，这是由动脉曲率半径增加引起的（拉普拉斯定律：张力=压力×半径）。9只3千克重的兔子在肾下腹主动脉植入了一个塑料插件。该插件旨在重现人工血管与小口径动脉吻合所引起的构象变化，同时不会显著改变血流。经计算，该插件引起的动脉壁张力增加幅度超过基线值的80%至100%。进行了主动脉造影、实时超声和计算机断层扫描（CT）以确认管腔内无血栓形成或插件移位。超声和CT扫描还证实了插件部位主动脉出现了预期的构象变化。植入后3天至6个月内取出了带有插件的主动脉。植入1至6个月后出现了增生性内膜下病变，其特征为纤维组织沉积、梭形细胞（可能是成纤维细胞）和/或覆盖有内皮的平滑肌细胞。相比之下，两只兔子在植入插件1分钟后取出，分别存活了37天和72天，主动脉完全愈合，未出现吻合口增生。本实验中诱导的动脉壁构象变化导致了与吻合口增生一致的病变形成。壁张力增加可能是这种反应的刺激因素。预防吻合口增生可能需要一种在不增加壁张力的情况下将移植物与动脉连接的方法。
