Current guidelines recommend pretreatment with a loading dose of clopidogrel before percutaneous coronary intervention (PCI) to reduce the incidence of periprocedural myocardial infarctions in patients undergoing PCI. However, because of concerns about postoperative bleeding, clopidogrel loading is frequently administered either immediately before or after PCI. Using the 2004/2005 Cornell Angioplasty Registry, we analyzed 1,041 consecutive patients undergoing urgent PCI for non-ST-elevation acute coronary syndrome. The patients were divided into 2 groups. The first group was the "preangiography clopidogrel therapy" group for those receiving chronic 75-mg clopidogrel therapy or receiving a clopidogrel loading dose (300 mg > or = 12 hours or 600 mg > or = 2 hours) before angiography according to the guidelines. The second group was the "in-laboratory 600-mg clopidogrel loading" group for the patients who received the clopidogrel loading dose <2 hours before PCI (immediately before or after PCI). The mean clinical follow-up was 23.8 + or - 7.6 months. Of the 1,041 study patients, 467 (44.9%) received clopidogrel before angiography and 574 (55.1%) received in-laboratory loading. The incidence of in-hospital death (0.4% vs 0.5%, respectively; p = 1.000), myocardial infarction (7.7% vs 6.8%, respectively; p = 0.630), and major adverse cardiovascular events (8.4% vs 7.1%, respectively; p = 0.484) were similar between the 2 groups. The Kaplan-Meier long-term survival rates were similar in the 2 groups (93.4% vs 95.8%, p log-rank = 0.152). After multivariate Cox regression analysis, administration of a 600-mg clopidogrel loading dose <2 hours before PCI did not have a significant effect on long-term mortality (hazard ratio 0.97, 95% confidence interval 0.54 to 1.75, p = 0.927). In conclusion, treatment with a 600-mg loading dose <2 hours before PCI is associated with similar short-term ischemic outcomes and long-term mortality compared to the currently recommended clopidogrel pretreatment regimen.
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