Abstract 11: Comparison Of Various Methods Of Assessment Of Intracranial Collaterals On The Pretreatment Ct-angiograms To Predict Outcomes In Acute Anterior Circulation Ischemic Stroke

Background: The presence of effective collateral blood flow patterns may influence response to intravenously administered tissue plasminogen activator (IV-tPA) in acute ischemic stroke (AIS). We compared various existing methods of scoring collaterals on the pre-treatment computed tomographic angiogram (CTA) of the brain for a reliable prediction of functional outcome in AIS patients. Methods: Consecutive AIS patients treated with IV-tPA within 4.5 hours of symptom-onset during 2007-2011 were included. Data were collected for demographics, vascular risk factors, National Institute of Health Stroke Scale (NIHSS) scores and stroke subtypes. Intracranial collaterals were evaluated by 2 independent blinded neuroradiologists via 4 predefined criteria- Miteff’s system that grades middle cerebral artery (MCA) collateral branches with respect to the sylvian fissure; Maas system that compares collaterals on the affected hemisphere against the unaffected side; modified Tan’s scale where collaterals in 50% or more of the MCA territory are classified as good; and a 20-point collateral grading scale in regions corresponding to Alberta Stroke Program Early CT score (ASPECTS) methodology. Good functional outcomes at 3-months were determined by modified Rankin scale (mRS) scores of 0-1. Results: CTA was performed in 115 patients with anterior circulation AIS before IV-tPA bolus. Median age 66yrs (range 35-92), 42% males, median NIHSS 19 points (range 3-30) and median onset-to-treatment time 155 minutes. Overall, 52 (45.2%) patients achieved good functional outcome at 3-months. Univariable analysis revealed younger age, absence of diabetes, lower pre-tPA NIHSS scores and good collaterals according to ASPECTS methodology as significantly associated with good functional outcomes. On multivariable logistic regression, only lower NIHSS (OR 1.111 per NIHSS point; 95% CI 1.023-1.206, p=0.013) and good collaterals by ASPECTS methodology (OR 1.117 per point; 95%CI 1.006-1.241, p=0.039) were found as independent predictors of good outcomes. Conclusion: Of the existing intracranial collaterals scoring systems, only the ASPECTS methodology serves as a reliable predictor of favorable outcomes at 3-months in patients with anterior circulation AIS.