Warfarin-associated intracerebral hemorrhage: volume, anticoagulation intensity and location.

BACKGROUND: Warfarin use increases mortality in patients with intracerebral hemorrhage (ICH). Larger hematoma volume and infratentorial location are both major determinants of poor outcome in ICH. Although warfarin-associated intracerebral hemorrhages have greater volumes, there is uncertainty about the effects of location. We aimed to investigate the influence of warfarin on hematoma volume and location. METHODS: We conducted a retrospective study of all patients hospitalized for ICH at a large stroke center from October 2007 to January 2012. Initial CT scans were used to quantify hematoma volumes using the computer-assisted planimetric analysis. Univariate and multivariable analyses determined the influence of warfarin on hemorrhage location. Median regression analysis was performed to estimate the effects of INR on hematoma volumes. RESULTS: We included 404 consecutive patients with ICH of whom 69 were on warfarin. Patients on warfarin had larger hematoma volumes (median 23.9mL vs. 14.2mL; P=0.046). In patients excessively anticoagulated with warfarin (defined as INR>3.0), compared with those in the therapeutic range, brainstem ICH was more frequent (24.0% vs. 6.1%; P=0.005). Patients with INR>3.0 had increased odds of infratentorial hemorrhage (OR 3.63; 95% CI 1.52-8.64; P=0.004) when compared to non-warfarin ICH patients. After adjustment for hematoma location, there was no significant association between INR and hematoma volume. CONCLUSIONS: Patients with warfarin-associated ICH have a predilection for brainstem ICH. After adjustment for ICH location, no relationship between admission INR and hematoma volume was found.