Still room for improvement: Preclinical and bench testing of a thin-strut cobalt-chromium bare-metal stent with passive coating.

There is a renewed interest in bare-metal stent (BMS) design as degradable polymer coatings are increasingly used as drug-delivery vehicles in drug-eluting stents (DESs), leaving it to the BMS platform to determine the long-term outcome of DES treatment. In this study comprising preclinical and bench tests, we compare two modern thin-strut BMSs of different design. Angiography, morphometry, and histopathology data were acquired in a porcine coronary artery model in a 28-day single-stent study (13 hybrid farm pigs) and in a 90-day overlapping-stent study (8 Yucatan mini-pigs). Standardized bench tests including ion release test were performed to compare mechanical performance of the two stent systems. We found that the optimized stent group induced significantly less neointimal formation and less inflammation than Multi-Link Vision in both (single stent and overlapping stent) porcine studies. The higher efficacy was also associated with a markedly reduced release of cobalt, nickel, chromium, and tungsten ions in physiological solution and better performance in mechanical delivery tests. In conclusion, a further increase in efficacy and better safety profile than the well-known Multi-Link Vision BMS can be achieved by careful optimization of the BMS backbone.