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The DAPT study (NEJM JW Cardiol Nov 16 2014) demonstrated an ischemic benefit and an increased risk for bleeding with prolonged dual antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation. Two additional studies provide further insight into this issue.
In a meta-analysis, investigators pooled the results of 14 randomized trials to compare an extended duration (>12 months) with a short duration (≤6 months) of DAPT in 69,644 patients who received varying durations of DAPT for a variety of cardiovascular disorders (not just post-stenting). At an average follow-up of 2 years, patients receiving extended- or short-duration DAPT had similar risks for all-cause and cardiovascular mortality (hazard ratios, 1.05 and 1.01, respectively).
In an open-label, manufacturer-funded, multicenter, randomized trial, investigators compared 6 months and 24 months of DAPT after implantation of at least one late-generation, everolimus-eluting stent (EES). Patients resistant to aspirin were excluded. Because of recruitment problems, the trial was discontinued prematurely; in all, 1850 patients were enrolled. Actual duration of DAPT was not as planned in 24% of patients in the short-duration arm and in 5% of those in the prolonged-therapy arm. The rate of the primary composite endpoint — death, myocardial infarction, urgent target-vessel revascularization, stroke, and major bleeding at 12 months — was about 1.5% in both groups.
Elmariah S et al. Extended duration dual antiplatelet therapy and mortality: A systematic review and meta-analysis. Lancet 2014 Nov 16; [e-pub ahead of print]. (http://dx.doi.org/10.1056/S0140-6736(14)62052-3)
Gilard M et al. Six-month versus 24-month antiplatelet therapy after implantation of drug eluting stents in patients non-resistant to aspirin: ITALIC, a randomized multicenter trial. J Am Coll Cardiol 2014 Nov 16 [e-pub ahead of print]. (http://dx.doi.org/10.1016/j.jacc.2014.11.008)
Comment
These studies add to our knowledge and to our interpretation of the larger DAPT study. The results of the meta-analysis are reassuring and suggest that the increase in all-cause mortality observed in the treatment group of DAPT is probably related to noncardiovascular deaths, partly related to the baseline imbalance in cancer rates, and unrelated to fatal bleeding or a drug effect. Despite methodological limitations, the lack of benefit with longer DAPT therapy in the randomized comparison in EES recipients is consistent with the EES subgroup analysis in the larger DAPT trial and emphasizes the need to individualize the decision about DAPT duration based on a variety of factors, including stent type.