Abstract WP140: Perfusion Collateral Index Predicts Infarct Growth in Successfully Reperfused Patients With Acute Ischemic Stroke

Abstract

Introduction: Robust collaterals are associated with lower rates of infarct growth and improved clinical outcomes in patients with acute ischemic stroke. Perfusion Collateral Index (PCI) and Hypoperfusion Intensity Ratio (HIR) have been shown to correlate with angiographic collaterals. We aimed to assess and compare the ability of PCI and HIR to predict infarct growth in anterior circulation large vessel occlusion (AC LVO) patients who underwent successful reperfusion. Methods: In this retrospective study, AC LVO stroke patients were included if they had pretreatment perfusion (CT or MR), successful reperfusion (mTICI > 2b), and follow up MRI within 24 hours from treatment. HIR (defined as volume of Tmax >10 sec/volume of Tmax >6 sec) was calculated by RAPID software (Version 5.0.4). PCI (defined as volume of delay 2-6 seconds x rCBV) was calculated using Olea software (SP.23). Infarct growth was calculated by subtracting baseline ischemic core (ADC <620 х 10 –6 mm2/s on MRI or rCBF <30% on CTP) from post-treatment MRI volume of DWI hyperintensity. Results: A total of 80 patients were included; 46 female, age (mean + SD): 70.2 + 13.1 years, NIHSS (median, IQR): 14, 8-19, and time from stroke-onset to reperfusion (mean + SD): 389 + 236 minutes. The infarct growth volume was 27 + 52 mL (mean + SD); 47 patients (58.7%) had infarct growth > 10 mL. ROC analysis for prediction of infarct growth > 10 mL revealed AUC/sensitivity/specificity of 0.70/55.3/84.8 for PCI at threshold <60, which was significantly higher (P=0.006) than HIR at threshold of >0.4 (0.50/74.5/24.2) (Figure). Multivariate logistic regression showed PCI (p=0.004) and time-to treatment (p=0.024) were the only independent variables to predict infarct growth. Conclusion: In conclusion, in patients with AC LVO stroke, poor baseline collateral perfusion defined by PCI <60 predicts infarction growth > 10 mL despite successful reperfusion. PCI was superior to HIR in the prediction of infarct growth.