Drug-eluting stents perform better than bare metal stents in small coronary vessels: a meta-analysis of randomised and observational clinical studies with mid-term follow up

Abstract

Background: We tested drug-eluting stent (DES) and bare metal stent (BMS) performance in small coronary vessels by means of meta-analysis of all available clinical studies.

Methods: The analysis included randomised controlled trials (RCT), subgroups of RCT and observational studies with a follow-up of at least six months comparing the use of DES and BMS during percutaneous interventions involving small coronary arteries (diameter<3mm). The primary endpoint was target vessel failure (TVF); the others were pooled and isolated major adverse cardiovascular events (MACE), stent thrombosis (ST), binary restenosis and late lumen loss at the longest available follow-up. The effect of treatment was evaluated in terms of odds ratios (OR) and 95% confidence intervals (95% CI) for binary variables, and mean difference (MD)± standard deviation (SD) for continuous variables. Fixed- or random-effect models were used depending on the statistical heterogeneity of studies. The analyses of major endpoints were stratified by study type, length of follow-up, and type of DES.

Results: We pooled 12 studies involving 3182 patients. Trial heterogeneity was a minor issue. TVF (OR: 0.35; CI: 0.24-0.51), MACE (OR: 0.36; CI: 0.29-0.45), binary restenosis (OR: 0.15; CI: 0.12-0.20) and late lumen loss (MD: -0.46; SD: -0.55 to -0.38) all significantly improved with DES treatment; ST (OR: 0.63; CI: 0.34-1.17) was not statistically different between studies.

Conclusions: DES are superior to BMS in terms of their efficacy in managing small coronary arteries (diameter<3mm), and at least equivalent in terms of safety. The use of DES should be considered the treatment of choice in this setting.