Inflammation and delayed endothelization with overlapping drug-eluting stents in a porcine model of in-stent restenosis

Abstract

Background This study evaluated the inflammatory reaction at the site of overlapping drug-eluting stents (DES) in a porcine model of in-stent restenosis. Methods and Results Twenty bare metal stents (BMS) (group 1; n=10), 20 sirolimus-eluting stents (SES) (group II: n=10), 20 paclitaxel-eluting stent (PES) (group III: n=10), and 10 PES and 10 SES (group IV: n=10) were overlapped in the left anterior descending coronary arteries of 40 pigs. Follow-up coronary angiography and histopathology were performed at 4 weeks after stenting. For the overlapped segments, the minimal luminal diameter at 4 weeks was smaller in group I than in the other groups (1.78 +/- 0.13 mm, 2.79 +/- 0.09 mm, 2.90 +/- 0.04 mm, 2.80 +/- 0.07 mm, respectively; p<0.001), and the neointimal area (5.51 +/- 0.58 mm(2), 2.38 +/- 0.53 mm(2), 2.07 +/- 0.37 mm(2), 2.39 +/- 0.58mm(2), respectively; p<0.001) and area stenosis (68.74 +/- 4.02%, 27.79 +/- 4.73%, 23.66 +/- 3.24%, 27.63 +/- 4.07%, respectively; p<0.001) were higher in group I than in the other groups; however, the inflammatory score was higher in group III than in the other groups (1.80 +/- 0.42, 2.10 +/- 0.32, 2.90 +/- 0.31, 2.50 +/- 0.52, respectively; p<0.001) and the endothelization score was lower in group III than in the other groups (2.80 +/- 0.42, 2.30 +/- 0.67, 1.30 +/- 0.48, 2.10 +/- 0.74, respectively; p<0.001). Conclusion Compared with BMS, DES inhibit neointimal hyperplasia, but inflammation and poor endothelization occur at the site of overlapping stents.