Mid- and Long-Term Outcome Comparisons of Everolimus-Eluting Bioresorbable Scaffolds Versus Everolimus-Eluting Metallic Stents

BACKGROUND: Percutaneous coronary interventions to implant bioresorbable vascular scaffolds (BVSs) were designed to reduce the late thrombotic events that occur with metallic stents. PURPOSE: To estimate the incidence of scaffold thrombosis after BVS implantation and compare everolimus-eluting BVSs with everolimus-eluting metallic stents (EESs) in terms of safety and efficacy at mid- and long-term follow-up in adults who had a percutaneous coronary intervention. DATA SOURCES: PubMed, EMBASE, the Cochrane Library, conference proceedings, and relevant Web sites from inception until 20 May 2017, without language restriction. STUDY SELECTION: 7 randomized trials and 38 observational studies (each with a minimum of 6 months and 100 patient-years of follow-up) in adults with coronary artery disease who had a BVS or an EES and reported scaffold or stent thrombosis (main outcome) or other secondary outcomes (such as death, myocardial infarction, or revascularization). DATA EXTRACTION: 2 reviewers independently extracted study data, rated study quality, and assessed strength of evidence. DATA SYNTHESIS: The pooled incidence of definite or probable scaffold thrombosis after BVS implantation was 1.8% (95% CI, 1.5% to 2.2%) at a median follow-up of 1 year (41 studies, 21 884 patients) and 0.8% (CI, 0.5% to 1.3%) beyond 1 year (14 studies, 4688 patients). Seven trials involving 5578 patients that directly compared BVSs with EESs showed an increased risk for definite or probable scaffold thrombosis (odds ratio [OR], 3.40 [CI, 2.01 to 5.76]) with BVSs at a median follow-up of 25 months. Increased risks were present at early (prominently subacute), late, and very late stages, and odds beyond 1 year were almost double those seen within 1 year. Bioresorbably vascular scaffolds increased risks for myocardial infarction (OR, 1.63 [CI, 1.26 to 2.10]), target lesion revascularization (OR, 1.31 [CI, 1.03 to 1.67]), and target lesion failure (OR, 1.37 [CI, 1.12 to 1.66]); the odds for these 3 end points also increased over time. The incidences of all-cause, cardiac, and noncardiac death and of target vessel and any revascularization did not differ. LIMITATION: Quality of observational studies was unclear, and some data were unpublished. CONCLUSION: Compared with EESs, BVSs increased the risks for scaffold thrombosis and other thrombotic events at mid- and long-term follow-up, and risks increased over time. PRIMARY FUNDING SOURCE: National Natural Science Foundation of China.