Drug-eluting stents versus bare metal stents for angina or acute coronary syndromes

Abstract

Background: Coronary artery stents are tiny tubular devices used to 'scaffold' vessels open during percutaneous transluminal coronary angioplasty (PTCA). Restenosis (re-narrowing) of vessels treated with stents is a problem; in order to reduce restenosis, stents that elute drugs over time are available. An earlier review reported limited benefit for these more expensive devices. There is a need to assess their clinical benefits now that longer term data are available. Objectives: To update the previously published review which aimed to assess the clinical effectiveness of routine stenting with drug-eluting compared with non-eluting coronary artery stents in adults with stable angina or acute coronary syndrome (including acute myocardial infarction and unstable angina). Search methods: The Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 10, 2012 on The Cochrane Library), MEDLINE (OVID, 1946 to October week 4 2012) and EMBASE (OVID, 1980 to 2012 week 43) were searched. We carried out handsearching (electronic) up to May 2012. No language restrictions were applied. Selection criteria: We included RCTs comparing DES with BMS used in conjunction with PTCA techniques in the review. Participants were adults with stable angina or acute coronary syndrome (ACS). We considered published and unpublished sources and included them if they reported outcome data of interest. Data collection and analysis: Two review authors independently extracted data, assessed trial quality and checked decisions within the group. Data extraction included combined cardiovascular events (major adverse cardiac event, target vessel failure); mortality; acute myocardial infarction (AMI); target lesion revascularisation (TLR); target vessel revascularisation (TVR) and thrombosis. Data synthesis included meta-analysis of combined cardiovascular events, mortality, AMI and revascularisation rates, presented as odds ratios with 95% confidence intervals (CI) using a fixed-effect model. We assessed heterogeneity between trials. Main results: The update of the review included 24 new trials (13,391 participants) resulting in a total of 71 trials (28,713 participants). In the main there were no statistically significant differences in mortality, AMI or thrombosis between DES and BMS, (the exceptions were sirolimus reporting significant differences in AMI at two and three years and Everolimus DES thrombosis rates at one year. These benefits were not evident at four or five years). For composite events, TLR and TVR reductions were evident with use of sirolimus, paclitaxel, dexamethasone, zotarolimus and (to a limited extent) biolimus A9, everolimus and unspecified-eluting stents e.g. sirolimus composite events at five years (OR 0.49; 95% CI 0.40 to 0.61). These effects are demonstrated in the longer term follow up. Subgroup analyses (e.g. diabetics) largely mirrored these findings. Authors' conclusions: Drug-eluting stents releasing sirolimus, paclitaxel, dexamethasone and zotarolimus reduce composite cardiac events. However, this reduction is due largely to reductions in repeat revascularisation rates as there is no evidence of a significant effect on rates of mortality, AMI or thrombosis.