2-year outcomes with the Absorb bioresorbable scaffold for treatment of coronary artery disease: a systematic review and meta-analysis of seven randomised trials with an individual patient data substudy

Background Bioresorbable vascular scaffolds (BVS) offer the potential to improve long-term outcomes of percutaneous coronary intervention after their complete bioresorption. Randomised trials have shown non-inferiority between BVS and metallic drug-eluting stents at 1 year in composite safety and effectiveness outcomes, although some increases in rates of target vessel-related myocardial infarction and device thrombosis were identified. Outcomes of BVS following the first year after implantation are unknown. We sought to ascertain whether BVS are as safe and effective as drugeluting stents within 2 years after implantation and between 1 and 2 years. Methods We did a systematic review and meta-analysis of randomised trials in which patients were randomly assigned to everolimus-eluting Absorb BVS or metallic everolimus-eluting stents (EES) and followed up for at least 2 years. We searched MEDLINE, the Cochrane database, TCTMD, ClinicalTrials. gov, Clinical Trial Results, CardioSource, and abstracts and presentations from major cardiovascular meetings up to April 1, 2017, to identify relevant studies. The primary efficacy outcome measure was the device-oriented composite endpoint (cardiac mortality, target vessel-related myocardial infarction, or ischaemia-driven target lesion revascularisation) and the primary safety outcome measure was definite or probable device thrombosis. Individual patient data from the four ABSORB trials were used for landmark and subgroup analysis and multivariable modelling. Findings We identified seven randomised trials in which 5583 patients were randomly assigned to Absorb BVS (n=3261) or metallic EES (n=2322) and followed up for 2 years. BVS had higher 2-year relative risks of the deviceoriented composite endpoint than did EES (9.4% [304 of 3217] vs 7.4% [169 of 2299]; relative risk [RR] 1.29 [95% CI 1.08-1.56], p=0.0059). These differences were driven by increased rates of target vessel-related myocardial infarction (5.8% [187 of 3218] vs 3.2% [74 of 2299]; RR 1.68 [95% CI 1.29-2.19], p=0.0003) and ischaemia-driven target lesion revascularisation (5.3% [169 of 3217] vs 3.9% [90 of 2300]; 1 . 40 [1.09-1.80], p=0.0090) with BVS, with non-significant differences in cardiac mortality. The cumulative 2-year incidence of device thrombosis was higher with BVS than with EES (2.3% [73 of 3187] vs 0.7% [16 of 2281]; RR 3.35 [95% CI 1.96-5.72], p<0.0001). Landmark analysis between 1 and 2 years also showed higher rates of the device-oriented composite endpoint (3.3% [69 of 2100] vs 1.9% [23 of 1193]; RR 1.64 [95% CI 1.03-2.61], p=0.0376) and device thrombosis (0.5% [11 of 2085] vs none [0 of 1183], p<0.0001) in BVS-treated patients than in EES-treated patients. Interpretation BVS was associated with increased rates of composite device-oriented adverse events and device thrombosis cumulatively at 2 years and between 1 and 2 years of follow-up compared with EES.