Abstract TP291: Middle Meningeal Artery Embolization for Acute and Acute-on-Chronic Subdural Hematomas: A Retrospective Cohort Study

Introduction: The underlying inflammatory response in subdural hematoma (SDH) may promote neoangiogenesis, impair hematoma resorption, and contribute to recurrence. Middle meningeal artery embolization (MMAE) has been proven in multiple trials as a safe and effective way to reduce chronic SDH recurrence. The efficacy of MMAE has not been established in the acute or acute-on-chronic SDH population. We describe the clinical and imaging outcomes of patients who underwent MMAE for acute and acute-on-chronic SDH. Methods: Following expedited institutional review board approval, we conducted a retrospective review of all consecutive patients with acute or acute-on-chronic SDH who underwent MMAE at our institution between July 2022 and April 2025. All data were entered into a secure, de-identified database for descriptive statistical analysis. Results: 123 MMAE procedures were performed in 97 consecutive patients (median age, 70 years; interquartile range IQR, 63 to 80); 70.1% were male, 62.9% White, 32% African American, and 3.1% Asian. Twelve patients (12.4%) had acute SDH, and 88 (88.6%) had acute-on-chronic SDH. Of the 123 procedures, 71 (57.7%) were unilateral (32 left-sided, 39 right-sided), and 26 (42.3%) were bilateral. Two procedure-related complications (1.6%) occurred (facial nerve palsy and femoral artery occlusion). At 90 days, follow-up imaging and clinical assessment were available for 53 patients (54.6%), corresponding to 67 embolizations. Complete radiographic resolution of the subdural hematoma (SDH) was observed in 13 embolizations (19.4%). 2 patients (3.8%) were readmitted to the hospital. No patients required surgical rescue. A total of 7 patients (7.2%) died within 90 days of the procedure from non-neurologic causes. All showed a reduction in the hematoma size. No symptomatic recurrences were observed. Conclusion: MMAE in acute and acute on chronic SDH was associated with low rates of procedural complications, substantial hematoma reduction, low rates of recurrence and readmission, and no requirement for surgical rescue. These findings support the safety and potential effectiveness of MMAE as a treatment option in select patients with acute or acute-on-chronic SDH.