Abstract 3286: Persistently Reduced Venous Drainage After Intravenous Thrombolysis is Associated With Poor outcome in Acute Anterior Circulation Ischemic Stroke

Abstract

Background- Significant numbers of acute ischemic stroke (AIS) patients recover with timely-administered intravenous tissue plasminogen activator (IV-TPA). However, rates and extent of recovery remain variable. Considering scarce and costly resources, early identification of reliable predictors for functional outcomes is important for planning rehabilitation strategies. We hypothesized that venous drainage would be impaired on the side of cerebral hypoperfusion due to acute occlusion of internal carotid or middle cerebral artery. The 2 internal cerebral veins (ICV) drain the deep parts of hemispheres and run backward to form great cerebral vein. Since ICVs are consistently seen on CT angiography (CTA), parallel and run very close to each other, even minor asymmetry in their filling can be easily diagnosed. ICV asymmetry in pre-TPA CTA can change in patients achieving arterial recanalization, rendering it less useful for predicting the long-term outcomes. Thus, we aimed at evaluating whether the presence of ICV asymmetry on follow-up CTA can predict the final outcome. Methods- Data from consecutive AIS patients treated with IV-TPA, in a standardized protocol, from Jan2007 to March2010 were included in a prospective registry at our tertiary center. In this study, we excluded posterior circulation strokes. Significant proportion AIS patients undergo CTA on day 2 after IV-TPA to assess the status of arterial patency. ICV asymmetry was assessed by 2 independent stroke neurologists/ neuroradiologists, blinded to patient data or outcomes. Functional outcomes were assessed by modified Rankin Scale (mRS) at 3-months, dichotomized as good outcome (mRS 0-1) and poor outcome (mRS 2-6). Data were analyzed for the early predictors of function outcome. Results- Of the total of 2238 patients admitted during the study period, 226 (10.1%) with anterior circulation AIS treated with intravenous thrombolysis were included. Median age was 65yrs (range 19-92), 63% males and median National Institute of Health Stroke Scale (NIHSS) 16points (range 4-32). Hypertension was the commonest vascular risk factor in 144 (76%) while 63 (33%) patients suffered from atrial fibrillation (AF). Overall, 108 (47.8%) patients achieved poor functional outcome at 3-months. ICV asymmetry could be assessed only in 103 (45.5%) patients on their follow up CTA films. Admission NIHSS score (OR1.08;95%CI 1.001-1.157,p=0.048) and ICV asymmetry on follow-up CT scan (OR 23.9;95%CI 5.15-63.99,p <0.0001) were associated with poor outcome at 3-months. Conclusion- Presence of the asymmetry of internal cerebral veins on the follow up CT angiography in acute ischemic stroke patients treated with IV-TPA can be used as an early predictor of poor functional outcome.