Warfarin use increased risk for brain bleed after IV tissue plasminogen activator use

In patients with acute ischemic stroke being treated with intravenous tissue plasminogen activator, baseline warfarin use increased the risk for symptomatic intracerebral hemorrhage, even with an international normalized ratio less than 1.7, according to the findings of a retrospective study.

Researchers enrolled consecutive patients with acute ischemic stroke being treated with IV tissue plasminogen activator and evaluated whether warfarin use at baseline (n=13; 12.1%) increased the risk for symptomatic intracerebral hemorrhage vs. patients not assigned to warfarin (n=94).

The mean age of patients was 69.2 years. Median INR was 1.04; all patients had INRs less than 1.7.

The overall rate of symptomatic intracerebral hemorrhage was 6.5%. However, patients taking warfarin at baseline had a 10-fold higher rate of symptomatic intracerebral hemorrhage vs. those not assigned to warfarin at baseline (30.8% vs. 3.2%; OR=13.5; P=.004).

Patients assigned to warfarin were more likely to be older (80.6 years vs. 67.6 years; P=.01), have atrial fibrillation (69.2% vs. 19.1%; P<.001) and more likely to have a higher initial INR score (1.21 vs. 1.03; P<.001) compared with those not assigned to warfarin.

Warfarin use at baseline remained significantly correlated with symptomatic intracerebral hemorrhage, even after adjustment for age, atrial fibrillation, NIH Stroke Scale score and INR (P=.004).

The researchers reported several limitations to the study, including small sample size and the inability to assess whether enhanced recanalization mediates the association between symptomatic intracerebral hemorrhage and warfarin use.

“Given these limitations, our study should serve as a hypothesis-generating report that requires confirmation in larger cohorts,” the researchers wrote.

Prabhakaran S. Arch Neurol. 2010;doi:10.1001/archneurol.2010.25.