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

ObjectivesThe aim of this study was to investigate the vascular responses and fates of the scaffold after bioresorbable vascular scaffold (BVS) implantation using multimodality imaging.BackgroundSerial comprehensive image assessments after BVS implantation in the context of a randomized trial have not yet been reported.MethodsIn 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).ResultsLuminal 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.ConclusionsIn 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)