Further information: Percutaneous Coronary Intervention for Acute Myocardial Infarction (see p1021) and  Drug-Eluting Coronary Stents (see p1031) from Cardiovascular Medicine, 3rd Edn*

Current guidelines for patients who have undergone percutaneous coronary intervention (PCI) recommend that patients who are not at risk of bleeding should be given clopidogrel (anti-platelet therapy), 75 mg daily, for 12 months following their procedure. However, the length of time that anti-platelet therapy should be further extended beyond 12 months has not been determined. The current study [1] evaluated data from two concurrent, randomized, clinical trials that compared continuation and discontinuation of clopidogrel: Correlation of Clopidogrel Therapy Discontinuation in Real-world Patients Treated with Drug-Eluting Stent Implantation and Late Coronary Arterial Thrombotic Events (REAL-LATE) and Evaluation of the Long-Term Safety after Zotarolimus-Eluting Stent, Sirolimus-Eluting Stent, or Paclitaxel-Eluting Stent Implantation for Coronary Lesion-Late Coronary Arterial Thrombotic Events (ZEST-LATE). Enrollment occurred from July 2007 through September 2008 in 22 cardiac centers in South Korea, and the two trials enrolled a total of 2701 patients who were free of major adverse cardiac or cerebrovascular events and major bleeding for at least 12 months after PCI. The group who had aspirin only and for whom clopidogrel was discontinued was assigned 1344 patients, and in the group for whom clopidogrel plus aspirin were continued, there were 1357 patients. The primary end point was the first occurrence of myocardial infarction (MI) or death from cardiac causes after group assignment. Secondary end points were death from any cause, MI, stroke, stent thrombosis, repeat revascularization, composite of MI or death from any cause, and major bleeding.

Cumulatively, the risk of primary outcome at 2 years was 1.8% with clopidogrel plus aspirin, as compared with 1.2% with aspirin alone (hazard ratio [HR], 1.65; 95% confidence interval [CI], 0.80–3.36; P=0.17). There was a non-significant difference in primary individual risks between the two groups, and there was a nonsignificant increase in composite risks in the group having both clopidogrel and aspirin.

The investigators concluded that the extended use of dual antiplatelet therapy (clopidogrel and aspirin) for more than 12 months after PCI was not significantly more effective than the use of aspirin alone to reduce risk of MI or death from cardiac causes.

[1] Park SJ, Park DW, Kim YH, et al. Duration of dual antiplatelet therapy after implantation of drug-eluting stents. N Engl J Med 2010;362:1374-82

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