Abstract 3998: Patients on Chronic Warfarin Therapy Who Present With an Acute Coronary Syndrome are High Risk and Receive Delayed and Inadequate Treatment
Background Little information is available about the subset of patients with an acute coronary syndrome (ACS) who are on chronic warfarin therapy. Hypothesis Patients on chronic warfarin who have an ACS may differ from those not on warfarin in terms of their baseline characteristics, hospital management, and outcomes.
Methods Between 1999 and 2005, 51,380 ACS patients were enrolled in the multinational GRACE registry. We compared baseline characteristics, hospital treatments, and outcomes of patients on chronic warfarin vs those not on warfarin.
Results 4.5% of ACS patients were on chronic warfarin, 53% of whom had a history of atrial fibrillation (vs 5.7% in patients without warfarin; P<0.001). These patients had higher-risk baseline characteristics and received less-aggressive antithrombotic therapy (Table⇓) in hospital and fewer evidence-based therapies at discharge (Table⇓). Fewer underwent angiography and revascularization, and median delays to angiography (63 vs 33 h, P<0.0001) and PCI (46 vs 22 h, P<0.0001) were longer vs patients not on chronic warfarin. STEMI patients on chronic warfarin were less likely to receive reperfusion therapy. Rates of mortality and bleeding were higher for patients on chronic warfarin. Risk-adjusted hospital mortality (using GRACE risk score) was substantially increased vs patients not on chronic warfarin (OR 1.42, 95% CI 1.18–1.70). History of atrial fibrillation (OR 2.45, 95% CI 2.12–2.85) and chronic warfarin (OR 1.39, 95%CI 1.14–1.68) were independent predictors of 6-month post-discharge mortality.
Conclusions ACS patients on prior chronic warfarin, who represent 4.5% of ACS patients, are at high risk of death and major bleeding. These patients receive less aggressive and delayed therapy compared with patients not on chronic warfarin and have higher-risk adjusted mortality in hospital and at 6 months.