Warfarin use and outcomes in patients with atrial fibrillation complicating acute coronary syndromes.

BACKGROUND: We examined warfarin use at discharge (according to Congestive heart failure, Hypertension, Age>75 years, Diabetes, Prior Stroke/transient ischemic attack score and bleeding risk) and its association with 6-month death or myocardial infarction in patients with post-acute coronary syndrome atrial fibrillation.
METHODS: Of the 23,208 patients enrolled in the Platelet IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy, Platelet IIb/IIIa Antagonist for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network A, and Superior Yield of the New Strategy of Enoxaparin, Revascularization and Glycoprotein IIb/IIIa Inhibitors trials, 4.0% (917 patients) had atrial fibrillation as an in-hospital complication and were discharged alive. Cox proportional hazards models were performed to assess 6-month outcomes after discharge.
RESULTS: Overall, 13.5% of patients with an acute coronary syndrome complicated by atrial fibrillation received warfarin at discharge. Warfarin use among patients with atrial fibrillation had no relation with estimated stroke risk; similar rates were observed across Congestive heart failure, Hypertension, Age>75 years, Diabetes, Prior Stroke/transient ischemic attack (CHADS(2)) scores (0, 13%; 1, 14%; > or = 2, 13%) and across different bleeding risk categories (low risk, 11.9%; intermediate risk, 13.3%; high risk, 11.1%). Among patients with in-hospital atrial fibrillation, warfarin use at discharge was independently associated with a lower risk of death or myocardial infarction within 6 months of discharge (hazard ratio 0.39; 95% confidence interval, 0.15-0.98).
CONCLUSION: Warfarin is associated with better 6-month outcomes among patients with atrial fibrillation complicating an acute coronary syndrome, but its use is not related to CHADS(2) score or bleeding risk. Copyright (c) 2010 Elsevier Inc. All rights reserved.