Optimal coating method for a dual-layer stent with sirolimus and alpha-lipoic acid in a porcine coronary restenosis model

The aim of this study was to evaluate the optimal method for coating a double-layer polymer coronary stent with sirolimus and alpha-lipoic acid (ALA) in a porcine coronary overstretch restenosis model. Pigs were randomized into three groups, in which the coronary arteries (10 in each group) were stented with a dual-layer stent with an inner layer of ALA and an outer layer of sirolimus (IAOS, n=10), a dual-layer stent with an inner layer of sirolimus and an outer layer of ALA (ISOA, n=10), or a commercial drug-eluting stent (biolimus-eluting stent, BES, n=10). Histopathological analysis was performed 28 days after stenting. There were no significant differences among the three groups in injury and inflammation scores. There were significant differences among the three groups in neointimal area (1.1±0.16 mm2 for IAOS vs. 1.3±0.41 mm2 for ISOA vs. 1.9±0.50 mm2 for BES, p<0.0001), and percentage of stenosis area (21.4±3.08% for IAOS vs. 29.9±7.72% for ISOA vs. 38.2±9.08% for BES, p<0.0001). Regarding the percentage of stenosis area, microcomputed tomography revealed significant differences between the three groups (23.8±3.51% for IAOS vs. 28.9±4.65% for ISOA vs. 36.4±8.07% for BES, p<0.05). Compared with commercial stent placement, both IAOS and ISOA resulted in significant inhibition of neointimal formation in a porcine coronary restenosis model. In addition, IAOS was more effective than ISOA in preventing anti-neointimal hyperplasia after stenting.