Subtherapeutic International Normalized Ratio in Warfarin-Treated Patients Increases the Risk for Symptomatic Intracerebral Hemorrhage After Intravenous Thrombolysis

Background and Purpose-There is uncertainty whether warfarin-treated patients (despite international normalized ratio <1.7) have increased risks of symptomatic intracerebral hemorrhage after intravenous thrombolysis. Methods-Vascular risk factors, stroke subtype, and outcome measures were compared between warfarin-and nonwarfarin-treated patients undergoing acute thrombolysis within 3 hours of symptom onset. Results-From 212 patients (mean age, 74 +/- 14 years; 50% men) studied, 14 (6.5%) had prior warfarin use. After adjusting for age, baseline National Institutes of Health Stroke Scale, and stroke subtype, warfarin-treated patients had significantly increased risks of developing symptomatic intracerebral hemorrhage (adjusted OR, 14.7; 95% CI, 1.3 to 54.3). A trend for poorer stroke recovery and increased mortality was observed in warfarin-treated patients on univariate, but not on multivariable, analyses. Conclusions-Warfarin-treated patients with stroke have increased risks of symptomatic intracerebral hemorrhage after thrombolytic treatment. These data raise safety concerns of thrombolytic treatment in warfarin-treated patients with subtherapeutic international normalized ratio. (Stroke. 2011;42:2333-2335.)