Aims Recent trials have examined the effect of prolonged dual antiplatelet therapy (DAPT) in a variety of patient populations, with heterogeneous results regarding benefit and safety, specifically with regard to cardiovascular and non-cardiovascular mortality.We performed a meta-analysis of randomized trials comparing more than a year of DAPT with aspirin alone in high-risk patients with a history of prior myocardial infarction (MI).
Methods and results A total of 33 435 patients were followed over a mean 31 months among one trial of patients with prior MI (63.3% of total) and five trials with a subgroup of patients that presented with, or had a history of, a prior MI (36.7% of total). Extended DAPT decreased the risk of major adverse cardiovascular events compared with aspirin alone (6.4 vs. 7.5%; risk ratio, RR 0.78, 95% confidence intervals, CI, 0.67–0.90; P ¼ 0.001) and reduced cardiovascular death (2.3 vs. 2.6%; RR 0.85, 95% CI 0.74–0.98; P ¼ 0.03), with no increase in non-cardiovascular death (RR 1.03, 95% CI 0.86–1.23; P ¼ 0.76). The resultant effect on all-cause mortality was an RR of 0.92 (95% CI 0.83–1.03; P ¼ 0.13). Extended DAPT also reduced MI (RR 0.70, 95% CI 0.55–0.88; P ¼ 0.003), stroke (RR 0.81, 95% CI 0.68–0.97; P ¼ 0.02), and stent thrombosis (RR 0.50, 95% CI 0.28–0.89; P ¼ 0.02). There was an increased risk of major bleeding (1.85 vs. 1.09%; RR 1.73, 95% CI 1.19–2.50; P ¼ 0.004) but not fatal bleeding (0.14 vs. 0.17%; RR 0.91, 95% CI 0.53–1.58; P ¼ 0.75).
Conclusion Compared with aspirin alone, DAPT beyond 1 year among stabilized high-risk patients with prior MI decreases ischaemic events, including significant reductions in the individual endpoints of cardiovascular death, recurrent MI, and stroke. Dual antiplatelet therapy beyond 1 year increases major bleeding, but not fatal bleeding or non-cardiovascular death.

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European Heart Journal
Erasmus MC: University Medical Center Rotterdam

Udell, J.A, Bonaca, M.P, Collet, J.P, Lincoff, A.M, Kereiakes, D.J, Costa, F, … Bhatt, D.L. (2016). Long-term dual antiplatelet therapy for secondary prevention of cardiovascular events in the subgroup of patients with previous myocardial infarction. European Heart Journal, 37(4), 390–399. doi:10.1093/eurheartj/ehv443