Abstract WP079: Predictors of Stroke Recurrence in Intracranial Atherosclerosis and Effect of Early Antithrombotic Initiation

Background: Intracranial atherosclerotic stenosis (ICAS) is a leading cause of ischemic strokes worldwide, with recurrence rates of 10-20% at one year. We aimed to determine the predictors of recurrent ischemic stroke due to ICAS at one year and evaluate the association of early antithrombotic therapy with stroke recurrence. Methods: We performed a retrospective cohort review of hospitalized patients aged 18-89 years with symptomatic ICAS (sICAS) at the University of Minnesota/MHealth Fairview system. sICAS was defined as 50-99% stenosis of an intracranial artery (ICA, vertebral, basilar, M1 or M2 MCAs) with acute infarct in the arterial territory. Demographic, clinical, imaging and treatment data were collected. Primary outcomes were recurrent ischemic stroke in the symptomatic territory and any intra/extra-cranial bleeding within one year. Fisher’s exact, or Wilcoxon rank sum test were used to characterize differences in demographic, clinical, and imaging variables between patients with and without recurrent ischemic stroke within one year. Predictive power of variables was evaluated using univariate logistic regression with five-fold cross validation. Results: Among 118 patients included, (mean age was 69 ± 13.5, 61 (51.6%) male, 117 (99%) non-Hispanic). 27 (22.9%) experienced recurrent ischemic stroke within one year. Five-fold cross-validation with univariate logistic regression analysis showed Prior infarct in the same territory (OR 3.29; 95% CI 1.19–9.02; p=0.02) and infarct on MRI, embolic (OR 9.07; 95% CI 2.19–47.81; p=0.004) and borderzone (OR 3.78; 95% CI 1.14–17.25; p=0.048) patterns conferred greatest risk, while basilar stenosis was linked to lower odds (OR 0.14; 95% CI 0.02–0.81; p=0.037). There was no significant association between early initiation of antithrombotic agents with recurrence risk (<12 hours: OR 1.05; 95% CI:0.35-2.92; p=1 and <24 hours: OR 0.88; 95% CI:0.33-2.27; p = 0.8). Patients with recurrent strokes had higher systemic bleeding risk (p=0.037), though no intracranial hemorrhages occurred. Conclusion: In sICAS, recurrent strokes risk within one year was significantly associated with borderzone or embolic infarct pattern and higher incidence of systemic bleeding. Early antithrombotic initiation within 12 or 24 hours was not associated with recurrent stroke. Further research into imaging biomarkers and risk stratification are needed to optimize treatment in these patients.