Abstract T P137: Cerebral Ischemic Events In Patients With Therapeutic Warfarin Treatment

Abstract

Background: Patients on long term warfarin treatment can have cerebral ischemic events despite therapeutic levels. We sought to determine unique patient attributes that result in ischemic events on therapeutic warfarin treatment. Methods: We reviewed the medical records and imaging data of consecutive patients with cerebral ischemic events who were on long term warfarin treatment over a 4 year period. We stratified the patients based on international normalized ratio (2.0-3.0 versus <2.0) and compared the demographic and clinical characteristics between the two groups of patients. Results: A total of 163 patients (mean age±SD; 77.3 ± 11.2) on long term warfarin treatment were admitted with cerebral ischemic events (97 ischemic strokes and 40 transient ischemic attacks). The mean age was not different between patients who were sub therapeutic and therapeutic on warfarin (78.2 ±11.6 versus 77.5±10.5, p=0.7). The proportion of patients with hypertension (87.2% versus 84.0%, p=0.6), diabetes mellitus (44.2% versus 50.0 %, p=0.5), and cigarette smoking (7.0% versus 6.0%, p=0.8), was similar between the two groups. Patients who were therapeutic on warfarin were more likely to have large vessel atherosclerosis (8.0% versus 2.3 %, p=0.1) and small vessel disease (2.0% versus 1.2 %, p=0.6) and less likely to have atrial fibrillation (66.0% versus 77.5%, p=0.2) as the underlying etiologies for ischemic events. IV alteplase was used in 5 and none of patients who were sub therapeutic and therapeutic on warfarin, respectively. Conclusions: Patients who have concurrent predisposing factors appear to be at risk for cerebral ischemic events despite therapeutic warfarin treatment and concomitant preventive strategies should be evaluated.