BACKGROUND Commercially available bioresorbable scaffold (BRS) has strut thickness of 156 microns. As such, it has potential for delivery challenges and higher thrombogenicity. We aimed to evaluate safety and efficacy of a novel thin strut (100 mm) sirolimus eluting BRS (MeRes100, Meril Life Sciences, Gujarat, India) against clinically used BRS (Absorb BVS, Abbott, Santa Clara, CA) in porcine coronary arteries. METHODS We performed a histological analysis of 6 young adult Yucatan minipigs at 30, 90 and 180 days. Therefore, in total 9 MeRes100 (n=3 per timepoint) and 6 Absorb (n=2 per timepoint) scaffolds were implanted among all three coronary arteries at the overstretch ratio of 1.1:1. A second group of 5 young adult Yucatan minipigs (MeRes100=9, Absorb=4) was used for a long-term study in which serial optical coherence tomography (OCT) measurements were performed immediately after implantation, at 45, 90, 180 days, 1 and 2 years. RESULTS At two years, lumen (MeRes100 7.07+/-1.82mm2 vs. Absorb BVS 7.57+/-1.39mm2, p=0.97), scaffold areas (MeRes100 9.73+/-1.80mm2 vs. Absorb BVS 9.67+/-1.25mm2, p=0.99) and late lumen gain (MeRes100 1.03+/-1.98mm2 vs. Absorb BVS 0.85+/-1.56mm2, p=0.99) were comparable between both devices. Also, the patency ratio (follow-up lumen area/follow-up reference vessel area) at 2 years was similar in both groups (MeRes100 0.82 +/- 0.20 vs. Absorb BVS 0.79 +/- 0.18, p=0.99). Importantly, radial strength expressed by acute or late recoil metrics were comparable between MeRes100 and Absorb BVS. In histology, no significant differences were observed in terms of lumen area, % area stenosis or neointimal area between the study groups at 30, 90 or 180 days. Also, healing and inflammation profiles were comparable up to 6 months for both devices. CONCLUSION The novel sirolimus-eluting BRS with thinner struts and hybrid cell design showed similar radial strength and equivalent inhibition of neointimal proliferation when compared to the benchmark Absorb BVS up to 2 years in normal porcine coronary arteries. Importantly, the MeRes100-treated arterial segments demonstrated equal evidence of positive remodeling and late lumen gain despite >30% lower strut thickness when compared to Absorb BVS.
Gasior, P., Cheng, Y., Xia, J., Conditt, G., McGregor, J., Virmani, R., … Kaluza, G. (2017). TCT-845 Two-Year Longitudinal Evaluation of a Second-Generation Thin-Strut Sirolimus-Eluting Bioresorbable Coronary Scaffold with Hybrid Cell Design in Porcine Coronary Arteries. Journal of the American College of Cardiology, 70(18), B341–B342. https://doi.org/10.1016/j.jacc.2017.09.1053