Lumen Gain and Restoration of Pulsatility After Implantation of a Bioresorbable Vascular Scaffold in Porcine Coronary Arteries

Abstract

Using intravascular ultrasound (IVUS) and histomorphometry, this study sought to evaluate the potential of nonatherosclerotic porcine coronary arteries to undergo progressive lumen gain and a return of pulsatility after implantation with an everolimus-eluting bioresorbable vascular scaffold (BVS). Unique benefits such as lumen gain and restored vasomotion have been demonstrated clinically after treatment with BVS; however, a more rigorous demonstration of these benefits with a randomized clinical trial has not yet been conducted. Seventy nonatherosclerotic swine received 109 everolimus-eluting BVS and 70 everolimus-eluting metal stents randomized among the main coronary arteries. Arteries were evaluated in vivo by angiography and IVUS and post-mortem by histomorphometry at time points from 1 to 42 months. From 1 to 6 months, both BVS- and everolimus-eluting metal stent-implanted arteries demonstrated stable lumen areas (LAs). From 12 months to 42 months, there was a progressive increase in the LA of arteries implanted with a BVS as assessed by histomorphometry and IVUS. This lumen gain in the implanted segment corresponded to an increase in the reference vessel LA. Normalization in the in-segment LA (LA:reference vessel LA) was observed qualitatively by angiography and quantitatively by IVUS. Additionally, BVS-implanted arteries demonstrated restored in-segment pulsatility on the basis of IVUS assessment of the differences in the mid-scaffold area between end-diastole to end-systole. Starting at 12 months, BVS-implanted porcine coronary arteries underwent progressive lumen gain and showed restored pulsatility. These benefits demonstrated preclinically may translate into improvements in long-term clinical outcomes for patients treated with BVS compared with conventional drug-eluting stents.