Abstract TP444: New Ischemic Lesions on Brain MRI in Patients With Blunt Traumatic Cerebrovascular Injury

Introduction: Patients admitted after high energy blunt trauma with extracranial cerebrovascular injuries on screening neck computed tomography angiography (CTA) represent a unique group of patients at risk of thromboembolic stroke. These arterial dissections account for >1,000 ischemic strokes in the United States per year. Although stroke prophylaxis with antithrombotics is widely used in this setting, the risk of ischemic brain injury is unknown. Methods: This prospective observational study included 20 adult blunt trauma patients admitted with a screening CTA showing extracranial carotid or vertebral artery injury. All subjects had no initial clinical evidence of ischemic stroke, were managed with antiplatelets and observation and had brain magnetic resonance imaging (MRI) within 14 days of admission. The MRIs included diffusion, susceptibility, and FLAIR sequences to distinguish acute ischemic lesions from contusions and chronic infarctions and were read by two neuroradiologists blind to the findings of the neck CTA. A negative binomial regression adjusted for age and Injury Severity Score (ISS) was used to assess association between artery injury and lesion counts. Results: There were 12 carotid injuries and 11 unilateral or bilateral vertebral artery injuries. Mean interval between injury and MRI scan was 6.9 days. New ischemic lesions in the territory of the affected artery were present in 10 (43%) of the injured artery territories. The mean number of ischemic lesions was 7.8 (range 2-25), which was higher for territories with artery injury (mean=3.17) than those without injury (mean=0.14). None of the lesions were symptomatic. Adjusted for age and ISS, those with artery injury had a 23-fold higher average count of lesions (p=0.0004). In a sensitivity analysis excluding lesion counts >1.5 standard deviation units, the association remained 11-fold higher count for artery injury (p=0.0107). Conclusions: In blunt trauma patients with CTA evidence of extracranial cerebrovascular injury and treated with antiplatelets, >40% of arterial injuries are associated with ischemic lesions on MRI. Ischemic lesions on MRI may be a useful endpoint for future clinical trials of antithrombotic strategies in patients with blunt cerebrovascular injury.