Objectives: We sought to characterize patterns of clopidogrel use before coronary artery bypass grafting(CABG) and examine the drug’s impact on risks for postoperative transfusions among patients with non-ST-segment elevation acute coronary syndromes(NSTE ACS). Background: Adherence in community practice to American College of Cardiology/American Heart Association guidelines for clopidogrel use among NSTE ACS patients has not been previously characterized. Methods: We evaluated 2,858 NSTE ACS patients undergoing CABG at 264 hospitals participating in the CRUSADE(Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines) Initiative. We examined the patterns of acute clopidogrel therapy and its association with bleeding risks among those having “early”CABG ≤5 days and again among those having “late”surgery >5 days after catheterization. Results: Within 24 h of admission, 852 patients(30%) received clopidogrel. In contrast to national guidelines, 87%of clopidogrel-treated patients underwent CABG ≤5 days after treatment. Among those receiving CABG within ≤5 days of last treatment, the use of clopidogrel was associated with a significant increase in blood transfusions(65.0%vs. 56.9%, adjusted odds ratio[OR] 1.36, 95%confidence interval[CI] 1.10 to 1.68) as well as the need for transfusion of ≥4 U of blood(27.7%vs. 18.4%, OR 1.70, 95%CI 1.32 to 2.19). In contrast, acute clopidogrel therapy was not associated with higher bleeding risks if CABG was delayed >5 days(adjusted OR 1.18, 95%CI 0.54 to 2.58). Conclusions: Despite guideline recommendations, the overwhelming majority of NSTE ACS patients treated with acute clopidogrel needing CABG have their surgery within ≤5 days of treatment. A failure to delay surgery is associated with increased blood transfusion requirements that must be weighed against the potential clinical and economic impacts of such delays. Objectives: We sought to characterize patterns of clopidogrel use before coronary artery bypass grafting (CABG) and examine the drug’s impact on risks for postoperative transfusions among patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS). Background: Adherence in community Practice to American College of Cardiology / American Heart Association guidelines for clopidogrel use among NSTE ACS patients has not been previously characterized. Methods: We evaluated 2,858 NSTE ACS patients undergoing CABG at 264 hospitals incorporated in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppressive Adverse Outcomes With Early Implementation of the ACC / AHA Guidelines) Initiative. We examined the patterns of acute clopidogrel therapy and its association with bleeding risks among those having “early” CABG ≤5 days and again among those having “late” surgery> 5 days after catheterization. Results: Within 24 h of admission, 852 patients (30%) received clo In contrast to national guidelines, 87% of clopidogrel-treated patients underwent CABG ≤5 days after treatment. Among those receiving CABG within ≤5 days of last treatment, the use of clopidogrel was associated with a significant increase in blood transfusions (65.0 % vs. 56.9%, adjusted odds ratio [OR] 1.36, 95% confidence interval [CI] 1.10 to 1.68) as well as the need for transfusion of ≥ 4 U of blood (27.7% vs 18.4%, OR 1.70, 95 % CI 1.32 to 2.19). In contrast, acute clopidogrel therapy was not associated with higher bleeding risks if CABG was delayed> 5 days (adjusted OR 1.18, 95% CI 0.54 to 2.58). Conclusions: Despite guideline recommendations, the overwhelming majority of NSTE ACS patients treated with acute clopidogrel needing CABG have their surgery within 5 days of treatment. A failure to delay surgery is associated with increased blood transfusion requirements that must be weighed against the potential clinical and economic impacts of such delays.