Abstract 207: CT Perfusion Increases Time to Reperfusion and May Not Enhance Patient Selection for Endovascular Reperfusion Therapies in Acute Ischemic Stroke

Abstract

Background: Advanced modality imaging with CT perfusion (CTP) is frequently employed to optimize patient selection for endovascular reperfusion treatment in stroke. Although acquisition of images can be obtained rapidly, delays in decision making may occur. Time delays may be balanced by the data obtained with regards to core infarct. The current study examines if CTP aids in selecting patients best suited for endovascular stroke interventions by assessing clinical outcomes, hemorrhage rates and final infarct volume. Methods: We retrospectively reviewed patients from seven institutions who utilize endovascular reperfusion therapies for acute ischemic stroke. Patients with anterior circulation strokes treated less than 8 hours from symptoms onset were included. Patients were selected with a non-contrast head CT or CTP based on institutional protocols. We reviewed demographic, radiographic, and angiographic information to compare CTP and CT. Outcomes were dichotomized to good (mRS 0–2) or poor (mRS>2). Hemorrhages were classified using the ECASS definition with a parenchymal hematoma (PH) type 2 classified as symptomatic hemorrhage. Infarct volumes were measured on diffusion weighted MRI imaging using summation of regions of interest. A univariate analysis was performed using the Fisher’s exact test for categorical variables and student’s t-test for continuous variables to determine the characteristics of patients undergoing CTP compared to non-contrast CT only. A binary logistic regression model was constructed using variables with a p-value < 0.20 in univariate analysis to determine if patients selected with CTP had longer times to treatment or differences in outcomes. Results: A total of 338 patients with a mean age of 67±14 years and mean NIHSS of 18±5 were included. There were no differences in baseline demographics including age, site of vascular occlusion, and pre-treatment NIHSS in patients selected with CTP compared to non-contrast. There was no difference in rates of symptomatic hemorrhage in patients imaged with CTP compared to CT (6.8% vs. 6.6%, p<0.82), good outcomes (36.5% vs. 38.9%, p<0.72) and final infarct volume (80±64 cm 3 vs. 88±62 cm 3 , p<0.32). Patients who were selected with CTP were noted to have significantly longer times from CT acquisition to groin puncture times and reperfusion compared to patients with non-contrast CT (132±57 mins. vs. 97±60 mins., p<0.01) and (227±109 mins. vs. 199±91 mins., p<0.001). Conclusion: There were no differences in hemorrhage rates or clinical outcomes in patients selected based on non-contrast head CT and CTP. Acquisition of CTP may lead to delays in initiating endovascular procedures. This analysis may be limited in power, but a future prospective study is being designed to determine if non contrast CT is not inferior to CTP in selecting patients for endovascular therapies in acute ischemic stroke.