Abstract 138: Hypoperfusion Delay Volume Predicts Early Stroke Recurrence Risk In Symptomatic Anterior Circulation Intracranial Atherosclerotic Disease

Introduction: Data on predictors of early stroke recurrence in patients with symptomatic intracranial atherosclerotic disease (sICAD) is limited. We hypothesized that hypoperfusion delay predicts stroke recurrence within 90-days. Methods: We retrospectively collected all patients hospitalized with anterior circulation sICAD over 3 years (April 2019-April 2022) at a comprehensive stroke center. We collected demographics, clinical risk factors, radiological variables, and treatment strategies. Patients with an indication for anticoagulation such as atrial fibrillation and those with intracranial stenting or angioplasty were excluded. The outcome (verified by two independent reviewers) was recurrent stroke within 90 days in the affected artery. We assessed factors associated with stroke recurrence. We measured the effect of hypoperfusion delay volume on stroke recurrence using Cox-regression models. Results: Out of 131 sICAD hospitalizations during the study period, 66 involved the middle cerebral artery (MCA) M1 segment or intracranial internal carotid artery (ICA) and 44 patients met the inclusion criteria. The mean age was 71 years and 41% were women; 75% were treated with best medical management (dual antiplatelet therapy/high intensity statin therapy); and 75% had baseline perfusion imaging performed. Over 90 days, 11/44 (25%) patients had recurrent stroke. Factors associated with recurrence stroke were no best medical management (15.2% vs. 54.5%, p = 0.02), hypoperfusion Tmax>4 sec mismatch volume (p = 0.003), and hypoperfusion delay Tmax>6 sec mismatch volume (p=0.01). Using Youden’s cutoff for Tmax>4 sec mismatch (13 mL) and for Tmax>6 sec mismatch (5 mL), the risk of recurrent stroke at 90 days in separate models was higher in patients with Tmax>4 sec delay mismatch volume > 13 mL (HR 11.98 95% CI 1.48-96.96 p=0.02) and Tmax>6 sec mismatch volume > 5 mL (HR 4.37 95% CI 1.02-18.82, p=0.048). Effect size of the associations did not meaningfully change after adjusting for best medical management. Conclusion: Hypoperfusion delay is associated with an increased recurrent stroke risk within 90 days in patients with sICAD, despite best medical management. Validation by large prospective studies is warranted.