Background and purpose: NOBORI biolimus A9-eluting stent (BES) is the third generation drug eluting stent (DES) with only abluminal biodegradable polymer. Recent clinical trials have indicated that the BES is non-inferior to the XIENCE V everolimus-eluting stent (EES). Meanwhile, potential superiority of biodegradable polymer BES over current generation DES has not been addressed. The aim of this preclinical study was to assess and compare the biocompatibility of both BES and EES in porcine coronary arteries.
Methods and materials: BES with length of 24-mm (n=9) and EES with length of 23-mm (n=9) were both implanted in porcine coronary arteries. At 28 days endothelium-dependent vasomotion was assessed by acetylcholine (Ach) and subsequently measurements of endothelial superoxide production, histological evaluations and microarray gene analyses were performed.
Results: Angiographic and histological in-stent stenoses were significantly suppressed in BES compared with EES. Histopathological assessment showed lower inflammatory score as well as fibrin and injury scores in BES as compared with EES. On the contrary, paradoxical vasoconstriction to Ach was frequently observed in EES-treated vessels compared with BES-treated vessels. Additionally, gene expressions of inflammatory cytokines and chemokines were upregulated in vessels treated with EES compared with BES in microarray pathway specific analyses.
Conclusions: Implantation of BES revealed less inflammation and foreign-body immunoreaction than EES, suggesting more enhanced biocompatibility of BES compared with EES at 28 days in porcine coronary arteries.
Keywords: Biodegradable polymer; Drug eluting stent; Gene expression; Histopathology.
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