The use of drug-eluting stents (DESs) in primary percutaneous coronary intervention (PPCI) has shown early benefit over bare-metal stents (BMSs) in decreasing adverse cardiac events. However, there are concerns regarding the increased risk of late and very late stent thrombosis (ST) after DES use.

This meta-analysis evaluated the available literature examining the outcomes of DESs and BMSs in PPCI after >3 years of follow-up. A total of 8 RCTs and 5 observational studies comparing DESs to BMSs in PPCI were included in the analysis.

RCTs included 5797 patients in whom first-generation DESs (sirolimus- or paclitaxel- eluting stents) were compared to BMS control arms. The following findings were reported from an analysis of the RCT data:

• Patients receiving DESs had a statistically significantly lower risk of target lesion revascularisation (odds ratio 0.48, CI, 0.37 to 0.61), target vessel revascularisation (0.53; 0.42 to 0.66), and accordingly major adverse cardiac events (0.69; 0.56 to 0.84).

• Incidence of ST was not different between groups (1.02; 0.76 to 1.37).

• There was no significant difference in mortality (0.88; 0.68 to 1.12) or recurrent myocardial infarction (0.97; CI 0.61 to 1.54).

Among the observational studies (n=4650):

• Fewer reported on target lesion revascularisation and target vessel revascularisation, but the trend remained in favour of DESs.

• A small but statistically significant increase in ST was noted with DES use (1.62; 1.18 to 2.21) at >3 years of follow up, without evidence of recurrent myocardial infarction.

• Those receiving DESs had a statistically significantly lower mortality compared to those receiving BMSs (0.65; 0.53 to 0.80, p <0.001).

The researchers conclude from the meta-analysis of RCTs that DES use resulted in decreased repeat revascularisation with no increase in ST, mortality, or recurrent myocardial infarction. They note that the meta-analysis of the observational studies came to different conclusions regarding DES use in PPCI, with decreased mortality and a small but significant increase in risk of ST. They discuss possible explanations for the differences between conclusions of RCT and observational data meta-analyses.