Discontinuation of dual antiplatelet therapy over 12 months after acute coronary syndromes increases risk for adverse events in patients treated with percutaneous coronary intervention: systematic review and meta-analysis.

Introduction: Duration of dual antiplatelet therapy (DAPT) following acute coronary syndrome (ACS) hospitalization remains to be defined, both for patients treated medically and for those undergoing percutaneous transluminal coronary angioplasty (PTCA).

Methods: PubMed, Cochrane, and Google Scholar were systematically searched for studies including patients presenting with ACS, and treated either with DAPT longer than or shorter than 12 months. Multivariable-adjusted risk estimates for death and recurrent ACS with stopping DAPT after 12 months (odds ratios [OR] 95% confidence intervals [CI]) were pooled after logarithmic transformation according to random-effect models with inverse-variance weighting.

Results: Five studies with 49,586 patients were included. Median age was 66 (64-67) years, with 67% (65-75) males. Myocardial infarction (MI) represented the admission diagnosis for 88% (60-100) of the patients, and 66% (50-74) were treated with stenting. After a follow-up of 2.1 years (1.5-2.7), 40% (35-46) still on DAPT after 12 months and the rates of death or recurrent ACS were 16.6 (14.5-17.0). Risk of adverse events for patients stopping DAPT after 1 year was significantly increased (OR = 1.19 [1.07-1.32]) for those receiving stents, but not for patients managed medically (OR = 1.13 [0.95-1.35]). The increased risk did not vary according to age, gender, myocardial infarction as admission diagnosis, and kind of stent.

Conclusions: Interruption of DAPT over 12 months after ACS increases the risk of adverse events for patients treated with PTCA, but not for those managed conservatively, independently from baseline features and admission diagnosis. This hypothesis-generating finding should be tested in randomized controlled trials.