Preclinical investigation of neoatherosclerosis in magnesium-based bioresorbable scaffolds versus thick-strut drug-eluting stents.

Aims Neoatherosclerosis is a frequent finding after implantation of permanent metallic stents. Bioresorbable scaffolds (BRS) are considered to reduce the incidence of neoatherosclerosis owing to their dissolution and consequent vascular restoration. The aim of this study was to evaluate the formation of neoatherosclerosis between magnesium-based BRS and metallic DES in a rabbit model of neoatherosclerosis and in proportion to the effect of high-dose statin medication. Methods and results Fully bioresorbable magnesium scaffolds (BRS, n=45) and permanent metallic DES of equivalent geometry and design (n=45) were implanted into iliac arteries of New Zealand White Rabbits (n=45) following endothelial balloon injury and cholesterol diet. Endothelialization was assessed in n=12 animals after 35 days using scanning electron microscopy (SEM), showing significantly enhanced reendothelialization above struts in the BRS (n=13) compared to DES (n=10). 11 animals were terminated for baseline assessment after 91 days while the remaining 22 animals were randomised to receive high-dose statin treatment (3mg/kg) or placebo. BRS-treated vessels showed a significant reduction in foam cell infiltration as a sign of early neoatherosclerosis by histology and OCT when compared to DES. Statin treatment resulted in significant reduction of foam cell infiltration in BRS and DES by histology. Conclusions Our findings suggest reduced neoatherosclerosis formation in magnesium-based BRS relative to DES. High dose statin treatment may be a promising measure to reduce neoatherosclerosis progression, both on its own and in synergy with site-targeted device-based treatment.