Prolonged dual antiplatelet therapy after percutaneous coronary intervention reduces ischemic events without affecting the need for repeat revascularization: insights from the CREDO trial.

BACKGROUND

Dual antiplatelet therapy reduces ischemic events after percutaneous coronary intervention (PCI) and in patients with acute coronary syndromes. The relationship between target vessel revascularization (TVR) and ischemic events in patients treated with aspirin and clopidogrel or aspirin alone from 1 month to 1 year after PCI has not been studied.

METHODS

Patients enrolled in the CREDO trial were treated with aspirin and clopidogrel or aspirin and placebo for up to 1 year. We compared the rates of TVR and ischemic events (cardiac death, myocardial infarction or stroke) in the two groups, and modeled the effect of clopidogrel treatment on ischemic events after adjusting for relevant parameters. RESULTS One month after PCI, 1,955 patients have remained asymptomatic. By 1 year, ischemic events occurred in 5.3% of placebo- and 3.1% of clopidogrel-treated patients; p = 0.02. The rate of TVR was 11.9% and 12.2%, respectively; p = 0.82. Only 7 patients (clopidogrel: 3 and placebo: 4) experienced TVR within 7 days of an ischemic event. After adjustment, long-term dual antiplatelet therapy was associated with a 48% reduction in events; p = 0.01. Patients who experienced TVR had a significantly higher rate of ischemic events than those without TVR, regardless of treatment assignment: 12.3% vs. 3.1%, respectively; p < 0.001.

CONCLUSION

Thus, after successful PCI, prolonged dual antiplatelet therapy reduces ischemic events without affecting TVR. Overall, patients with TVR experienced an ischemic event much more often that was not related to the PCI vessel. This suggests that the benefit of antiplatelet therapy after coronary revascularization is indexed to the patient's underlying atherothrombotic process, rather than the artery that underwent intervention.