Early, late and very late incidence of bioresorbable scaffold thrombosis: a systematic review and meta-analysis of randomized clinical trials and observational studies.

INTRODUCTION: The aim of this paper was to determine the incidence of bioresorbable vascular scaffold thrombosis.

EVIDENCE ACQUISITION: A systematic review of the published literature between October 2012 and August 2016 was performed using PubMed, Medline and Embase databases. Articles published in the English language that reported the rate of bioresorbable scaffold thrombosis according to Academic Research Consortium criteria were included. Titles and abstracts were screened independently by two authors and further evaluated and assessed for study details, population characteristics and scaffold thrombosis rates. Scaffold thrombosis rates were pooled with meta-analysis using a random effect model. Meta-regression was performed to explore the predictors of device thrombosis. Randomized clinical trials (RCT), observational registries and case series of patients with obstructive coronary artery disease treated with the ABSORB bioresorbable scaffolds (BVS) that reported the rate of definite or probable scaffold thrombosis and the time of the event after implantation (i.e., acute, sub-acute, late and very late) were selected.

EVIDENCE SYNTHESIS: Overall, 16,830 patients treated with ABSORB BVS in 59 studies were included. A total of 256 definite or probable scaffold thrombosis (ScT) were identified and included in the present analysis. The overall rate of definite or probable ScT was 1.8% (CI 95% 1.5% to 2.0%) the median follow-up was 12.0 months (interquartile range 7.5 to 15). The rate of very late definite or probable ScT was 1.0% (95% CI 0.6% to 1.5%; 10 studies, 2331 patients). A higher rate of definite and probable scaffold thrombosis was found in studies with patients presenting with acute myocardial infarction (3.6% vs. 1.8%, Q=13.9, df=1, P=0.010). In the meta-regression analysis, the residual per cent diameter stenosis was the only factor associated with ST after scaffold implantation (coefficient 0.091, 95% CI -0.0009 to 0.183, P=0.052).

CONCLUSIONS: Using the largest available dataset of patients treated in randomized trials and observational registries, the present meta-analysis shows that the overall rate of definite or probable ScT is 1.8%, with a rate of very late ST of 1.0%. Residual stenosis after scaffold implantation was associated with the occurrence of scaffold thrombosis.