Shorter (≤ 6 months) versus longer (≥12 months) duration dual antiplatelet therapy after drug eluting stents: A meta-analysis of randomized clinical trials

Objective: Optimal duration of dual antiplatelet therapy (DAPT), defined as use of both aspirin and a P2Y12 receptor inhibitor, after implantation of drug eluting stents (DES) is still subject of ongoing debate. We systematically review efficacy and safety of ≤6 months versus ≥12 months DAPT after implantation of DES. Methods: PubMed, Scopus, Cochrane, and clinicaltrials.gov databases were searched for studies published until 30^th November 2013. The studies were limited to randomized clinical trials. Independent observers abstracted the data on outcomes, characteristics, and qualities of studies included. Random effect model was employed for meta-analysis. Heterogeneity of studies included was analyzed using I² statistics. Results: In four randomized clinical trials published involving 8,163 patients with DES, 4,081 patients were randomized to shorter and 4,082 patients to longer duration DAPT. The P2Y12 receptor inhibitor used in all four studies was clopidogrel. Longer duration of DAPT did not reduce risk of all cause mortality (pooled OR 0.89, 95% CI 0.67-1.17, P = 0.4, I² = 0%), myocardial infarction (pooled OR 1.16, 95% CI 0.85-1.57, P = 0.35, I² = 0%) cardiac death (pooled OR 0.88, 95% CI 0.61-1.25, P = 0.47, I² = 0%), stent thrombosis (pooled OR 1.29, 95% CI 0.76-2.21, P = 0.35, I² = 0%) or cerebrovascular accidents (pooled OR 0.73, 95% CI 0.41-1.27, P = 0.26, I² = 0%). Longer duration of DAPT was associated with increased risk of TIMI major bleeding (pooled OR 0.51, 95% CI 0.29-0.89, P = 0.02, I² = 0%). Conclusion: There was no difference in efficacy outcomes between ≤6 months of DAPT and ≥12 months of DAPT in patients with coronary artery disease and DES implantation. Moreover, longer duration of DAPT is associated with increased risk of bleeding complications.