Background-Whether triple antiplatelet therapy is superior or similar to dual antiplatelet therapy in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention in the era of drug-eluting stents remains unclear. Methods and Results-A total of 4203 ST-segment elevation myocardial infarction patients who underwent primary percutaneous coronary intervention with drug-eluting stents were analyzed retrospectively in the Korean Acute Myocardial Infarction Registry (KAMIR). They received either dual (aspirin plus clopidogrel; dual group; nϭ2569) or triple (aspirin plus clopidogrel plus cilostazol; triple group; nϭ1634) antiplatelet therapy. The triple group received additional cilostazol at least for 1 month. Various major adverse cardiac events at 8 months were compared between these 2 groups. Compared with the dual group, the triple group had a similar incidence of major bleeding events but a significantly lower incidence of in-hospital mortality. Clinical outcomes at 8 months showed that the triple group had significantly lower incidences of cardiac death (adjusted odds ratio, 0.52; 95% confidence interval, 0.32 to 0.84; Pϭ0.007), total death (adjusted odds ratio, 0.60; 95% confidence interval, 0.41 to 0.89; Pϭ0.010), and total major adverse cardiac events (adjusted odds ratio, 0.74; 95% confidence interval, 0.58 to 0.95; Pϭ0.019) than the dual group. Subgroup analysis showed that older (Ͼ65 years old), female, and diabetic patients got more benefits from triple antiplatelet therapy than their counterparts who received dual antiplatelet therapy. Conclusions-Triple antiplatelet therapy seems to be superior to dual antiplatelet therapy in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention with drug-eluting stents. These results may provide the rationale for the use of triple antiplatelet therapy in these patients. (Circulation. 2009;119:3207-3214.)

High-dose aspirin has been reported to aggravate coronary artery spasm (CAS). However, it is unknown whether low-dose aspirin (LDA; 100 mg) has deleterious impact on CAS. We assessed the impact of LDA on CAS induced by intracoronary acetylcholine (ACh) provocation test. A total of 2789 consecutive patients without significant coronary artery disease who underwent ACh test between November 2004 and March 2010 were enrolled. The patients were divided into two groups: the aspirin group taking LDA before ACh test (n=221) and the no aspirin group not taking aspirin (n=2568). At baseline, the prevalence of old age, diabetes mellitus, hypertension, and hyperlipidemia were higher in the aspirin group. During the ACh test, the incidence of significant CAS, ischemic chest pain, as well as severe and multivessel spasm was higher in the aspirin group. The response rate to lower ACh dose was higher in the aspirin group. Multivariate analysis showed that the previous use of LDA was an independent predictor of CAS (adjusted odds ratio, 1.6, 95% confidence interval, 1.0-2.3; p=0.031). However, it is likely that the association of LDA and CAS that we have observed is not causal but may be hypothesis generating due to significant baseline differences. Further, male gender, old age, lipid-lowering drugs, baseline spasm, and myocardial bridge were independent predictors of CAS. LDA was more frequently associated with CAS and ischemic symptoms, as well as severe and multivessel spasm, suggesting the patients who have received LDA would require more intensive medical therapies and close follow up.

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