Abstract WMP67: Cerebral Collateral Flow State Correlates With Stroke Severity And Functional Outcomes

Abstract

Introduction: Hypoperfusion index ratio (HIR) measured by computerized tomography perfusion (CTP) has been shown to predict collateral flow state in acute ischemic stroke (AIS). Low HIR (<0.4) is indicative of good collateral flow state. Hypothesis: Good collateral flow state correlates with lower stroke severity and better clinical outcome at discharge. Methods: Data from AIS patients who underwent CTP during initial stroke evaluation were linked with Get With the Guideline database in a comprehensive stroke center between 2018 and 2020. Patients with good collateral flow (HIR<0.4) were compared to those with poor collateral flow (≥0.4) group. They were stratified based on modified Rankin Score (mRS) at discharge into good outcome (mRS 0-2) or poor outcome (mRS 3-6). In addition to demographics, and risk factors data was collected on the initial stroke severity using the NIH stroke scale (NIHSS). Continuous variables were compared using t-test (parametric) and Mann-Whitney U test (non-parametric). Univariate and multivariable analyses (multiple logistic regression) were used to test the association between good collateral flow state and good discharge outcome. Results: CT perfusion data was obtained in 1442 patients, after excluding patients who underwent thrombectomy and all non-vascular etiologies of stroke like presentation, there was 890 patients (age 68±14, 52% male, 50% white, 50% black/others), of who 756 (85%) demonstrated good collateral flow and 134 (15%) showed poor collateral flow. Those with good collateral flow were younger (68±14 vs. 70±15, p=0.07) and lower median NIHSS (6 IQR 3-10 vs. 13 IQR 6-18, p<0.001). Good collateral flow was associated with good outcome on discharge (OR 2.2, 95% CI 1.5-3.3). The association remained significant after adjustment for age, gender, race, hypertension, diabetes, coronary artery disease, congestive heart failure and atrial fibrillation (adjusted OR 2.2 (1.4-3.3). Conclusions: In patients presenting with AIS, good collateral flow state was associated with lower stroke severity. It was independently associated with good outcome after adjustment for several comorbidities. Based on our study results, CT perfusion imaging may have utility in predicting stroke severity and discharge outcome.