Abstract Body: Background: Symptomatic intracranial atherosclerotic disease carries a high stroke recurrence rate. Accurate prediction of stroke recurrence is critical for improving patient outcomes through timely and targeted interventions. Prior studies have shown that impaired distal perfusion is a driver of early recurrence. This study aims to validate T max delay and mismatch as predictors of 30-day ischemic stroke recurrence.

Methods: This is a single-center study from a comprehensive stroke center including hospitalized patients with symptomatic intracranial arterial stenosis (50-99%) of the intracranial ICA and proximal middle cerebral artery (M1 or proximal M2). The study outcome was recurrent ischemic stroke by day 30. We determined associations of baseline demographics, vascular risk factors, clinical, laboratory variables, imaging variables, and in-hospital treatments with study outcome. Optimal threshold values for perfusion delay volume and perfusion mismatch volume were identified using the Stata module cutpt by the Liu method. Variables with p<0.05 on univariate analyses (Wilcoxon rank-sum test and chi-square test) were identified as important outcome predictors.

Results: We identified 114 patients hospitalized with symptomatic intracranial stenosis who met the inclusion criteria. 28 patients (24.6%) had a recurrent ischemic stroke within 30 days. Optimal threshold values were determined as 149.5 ml for T max of 4 seconds, 61.5 ml for T max of 6 seconds, 129.5 ml for mismatch volume at T max of 4 seconds, and 57.5 ml for mismatch volume at T max of 6 seconds. Predictors of early recurrence were younger age (66.5 vs. 74.6, p=0.038), increased hemoglobin A1c (6.2 vs. 5.7, p=0.035), home aspirin (50.0% vs. 23.3%, p=0.007), mismatch volume at T max of 4 seconds (p=0.017), and mismatch volume at T max of 6 seconds (p=0.015).

Conclusions: Key predictors of early recurrence in symptomtic ICAS include impaired distal perfusion, specifically mismatch volume at T max of 4 seconds and at T max of 6 seconds, and already being on antiplatelets prior to the event. Further research is required to confirm these findings and evaluate reperfusion strategies for individuals with impaired perfusion.