Randomized Comparison Between Everolimus-Eluting Bioresorbable Scaffold and Metallic Stent: Multimodality Imaging Through 3 Years

Abstract

Objectives: The aim of this study was to investigate the vascular responses and fates of the scaffold after bioresorbable vascular scaffold (BVS) implantation using multimodality imaging.

Background: Serial comprehensive image assessments after BVS implantation in the context of a randomized trial have not yet been reported.

Methods: In the ABSORB Japan trial, 400 patients were randomized to a BVS (n = 266) or a cobalt-chromium everolimus-eluting stent (n = 134). Through 3 years, patients underwent serial angiography and intravascular ultrasound or optical coherence tomography (OCT).

Results: Luminal dimension at 3 years was consistently smaller with the BVS than with the cobalt-chromium everolimus-eluting stent (mean angiographic minimal luminal diameter 2.04 ± 0.63 mm vs. 2.40 ± 0.56 mm, mean difference -0.37 mm [95% confidence interval: -0.50 to -0.24 mm]; p < 0.001), mainly because of smaller device area (6.13 ± 2.03 mm² vs. 7.15 ± 2.16 mm², mean difference -1.04 mm² [95% confidence interval: -1.66 to -0.42 mm²]; p < 0.001), and larger neointimal area (2.10 ± 0.61 mm² vs. 1.86 ± 0.64 mm², mean difference 0.24 mm² [95% confidence interval: 0.06 to 0.43 mm²]; p = 0.01) by OCT. BVS-treated vessels did not show previously reported favorable vessel responses, such as positive vessel remodeling, late luminal enlargement, and restoration of vasomotion, although the OCT-based healing score was on average zero (interquartile range: 0.00 to 0.00). At 3 years, intraluminal scaffold dismantling (ISD) was observed in 14% of BVS. On serial OCT, ISD was observed in 6 lesions at 2 years, where the struts had been fully apposed at post-procedure, while ISD was observed in 12 lesions at 3 years, where 8 lesions were free from ISD on 2-year OCT. In 5 cases of very late scaffold thrombosis, strut discontinuities were detected in all 4 cases with available OCT immediately before reintervention.

Conclusions: In this multimodality serial imaging study, luminal dimension at 3 years was smaller with the BVS than with the cobalt-chromium everolimus-eluting stent. ISD, suspected to be one of the mechanisms of very late BVS thrombosis, was observed in a substantial proportion of cases at 3 years, which developed between post-procedure and 2 years and even beyond 2 years. (AVJ-301 Clinical Trial: A Clinical Evaluation of AVJ-301 [Absorb™ BVS] in Japanese Population [ABSORB JAPAN]; NCT01844284).

Keywords: bioresorbable scaffold; optical coherence tomography; percutaneous coronary intervention; stable angina.