Internal Cerebral Vein Asymmetry on Follow-up Brain Computed Tomography after Intravenous Thrombolysis in Acute Anterior Circulation Ischemic Stroke Is Associated with Poor Outcome

Abstract

Identifying early predictors of functional outcome after acute ischemic stroke (AIS) is important for planning rehabilitation strategies. Internal cerebral veins (ICV) drain deep parts of brain, run parallel to each other, and consistently seen on computed tomography angiography (CTA). Even minor asymmetry in their filling can be identified. We hypothesized that venous drainage would be impaired in patients with acute occlusion of internal carotid artery or middle cerebral artery. Because systemic thrombolysis can alter the vascular findings, we evaluated the relationship between ICV asymmetry on follow-up CTA and functional outcome. Consecutive AIS patients treated with intravenous thrombolysis between 2007 and 2010 were included. ICV asymmetry was assessed by 2 independent blinded stroke neurologists/neuroradiologists. Functional outcome was assessed by the modified Rankin Scale (mRS) at 3months, dichotomized as good (0-1) and poor (2-6). Data were analyzed for predictors of functional outcome. Of 2238 patients with AIS, 226 (10.1%) anterior circulation AIS patients received intravenous thrombolysis. The median age was 65years (range 19-92), 44% were men, and median National Institutes of Health Stroke Scale (NIHSS) score was 16 points (range 4-32). Hypertension was the commonest risk factor in 173 (76.5%) patients, whereas 78 (34.5%) had atrial fibrillation. ICV asymmetry on follow-up CTA was assessed in 103 (45.5%) patients. Admission NIHSS score (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.079-1.201, P=.046), change in NIHSS score during first 24hours (OR .737; 95% CI .672-.807, P<.0001), and ICV asymmetry on follow-up CTA (OR 20.3; 95% CI 4.67-52.07, P<.0001) independently predicted poor outcome at 3 months. ICV asymmetry on follow-up CTA after intravenous thrombolysis is an early predictor of poor functional outcome.