Two-year longitudinal evaluation of a second-generation thin-strut sirolimus-eluting bioresorbable coronary scaffold with hybrid cell design in porcine coronary arteries

Background: The first commercially available bioresorbable scaffold (BRS) had a strut thickness of 156 microns. As such, it had the potential for delivery challenges and higher thrombogenicity. The aim herein, is  to evaluate biomechanical performance, pharmacokinetics and vascular healing of a novel thin strut (100 µm) sirolimus eluting BRS (MeRes-100, Meril Life Sciences, Gujarat, India) against the once clinically used BRS (Absorb BVS, Abbott, Santa Clara, CA) in porcine coronary arteries. Methods: Following device implantation, angiographic and optical coherence tomography (OCT) evaluation were performed at 45, 90, 180 days, 1 year and 2 years. Histological evaluation was performed at 30, 90 and 180 days. Results: At 2 years, both lumen (MeRes-100 7.07 ± 1.82 mm 2 vs. Absorb BVS 7.57 ± 1.39 mm 2 , p = NS) and scaffold areas (MeRes-100 9.73 ± 1.80 mm 2 vs. Absorb BVS 9.67 ± 1.25 mm 2 , p = NS) were comparable between tested and control scaffolds. Also, the late lumen area gain at 2 years was similar in both groups tested (MeRes-100 1.03 ± 1.98 mm 2 vs. Absorb BVS 0.85 ± 1.56 mm 2 , p = NS). Histologic examination up to 6 months showed comparable healing and inflammation profiles for both devices.  Conclusions: The novel sirolimus-eluting BRS with thinner struts and hybrid cell design showed similar biomechanical durability and equivalent inhibition of neointimal proliferation when compared to the first-ever Absorb BVS up to 2 years in normal porcine coronary arteries.