Supplementary Material for: Imaging Markers Predict the Short-term and Long-term Stroke Recurrence in Symptomatic Intracranial Atherosclerotic Disease

Introduction: Symptomatic intracranial atherosclerotic disease (ICAD) is associated with a high risk of stroke recurrence despite aggressive medical management. However, recurrence rates and risk factors are less studied in non-Western settings. The study evaluated the clinical and imaging predictors of early and late stroke recurrence in patients with symptomatic ICAD in India. Methods: This ambispective cohort study enrolled patients with symptomatic ICAD within one month of symptom onset from a tertiary stroke care hospital. The intracranial arterial stenosis grade and length, infarct patterns, white matter hyperintensity (WMH), and collateral flow were documented. The primary outcome was recurrent stroke or transient ischemic attack (TIA) within 3 months and 1 year. Results: Results: Of 876 patients with large artery atherosclerosis, 229 patients were included (mean age 59.7±10.2 years; men, 72.9%). At the end of one-year follow-up, recurrent ischemic stroke or TIA occurred in 55 (24%) patients. Of these, 47 (20.5%) patients had stroke recurrence within 3 months (early), and 14 (6.1%) patients had stroke recurrence after 3 months to one year (late). Six patients had both early and late stroke recurrence. A territorial and cortical infarct pattern (p=0.038), moderate to severe WMH (p=0.050), hypertension (p=0.040), diabetes (p=0.043), and coronary artery disease (p=0.034) predicted early stroke recurrence. A territorial and cortical infarct pattern (p=0.026), greater length of stenosis (p=0.045), diabetes (p=0.026), and coronary artery disease (p=0.044) predicted late recurrence. On multivariate analysis, a territorial and cortical infarct pattern (adj. OR, 2.15; 95% CI, 1.09-4.26; p= 0.028) independently predicted early stroke recurrence. Conclusion: A territorial and cortical infarct pattern is an independent predictor of early stroke recurrence, suggesting the role of artery-to-artery embolism and plaque instability as a potential mechanism of early stroke recurrence in patients with symptomatic ICAD.