Purpose: To evaluate the development of neointimal hyperplasia after implantation of drug-eluting stents (paclitaxel) compared to bare metal stents in porcine internal carotid arteries (ICAs).
Methods: While drug-eluting stents have effectively reduced neointimal proliferation in porcine external carotid arteries, the porcine internal carotid artery (ICA) is more sensitive to shear stress and altered flow conditions. Thus, a study was conducted to evaluate bare vs. drug-eluting stents in porcine ICAs. Under general anesthesia, 18 domestic pigs were implanted with paclitaxel-eluting (n = 18) and bare (n = 18) stents in the left and right ICAs, respectively. After 1 and 3 months, control carotid angiography was performed, followed by histopathological and histomorphometric analyses of the stented ICA.
Results: Histopathological results (fibrin deposition, necrosis, inflammation) were similar in the groups at 1 and 3 months. Moreover, the injury score and rate of endothelialization did not differ between the groups. Histomorphometric analysis after 1 month revealed significantly (p<0.05) less neointimal hyperplasia after implantation of paclitaxel-eluting stents. The antiproliferative effect of paclitaxel-eluting stents were maintained during the 3-month follow-up: the neointimal area was 0.7 ± 0.5 vs. 1.2 ± 0.6 mm(2) (p<0.01), the area stenosis was 23.5% ± 13.9% vs. 37.8% ± 14.4% (p<0.01), the maximal neointimal thickness was 0.2 ± 0.1 vs. 0.2 ± 0.9 mm (p<0.05) in paclitaxel-eluting vs. bare stents, respectively. Implantation of paclitaxel-eluting and bare stents did not lead to edge restenosis or vessel remodeling in porcine ICAs at 1 or 3 months.
Conclusion: Compared to bare metal stents, drug-eluting stents implanted in the porcine ICA produced significantly less neointimal hyperplasia.