Abstract 112: Impact of Baseline Antiplatelet & Antithrombotic Use on Outcomes of MMA Embolization for Chronic Subdural Hematoma

Background Chronic subdural hematoma (cSDH), a common condition in the elderly, often requires surgical intervention due to substantial morbidity. Recurrence after surgical evacuation ranges from 2% to 37%. Middle meningeal artery (MMA) embolization has emerged as a promising minimally invasive alternative. Many patients with cSDH have cardiovascular comorbidities and receive antiplatelet or anticoagulant therapy, but the impact of baseline antithrombotic use on MMA embolization outcomes remains poorly defined. Understanding this relationship is key to optimizing treatment strategies and improving outcomes. Methods We retrospectively analyzed patients with cSDH undergoing MMA embolization (MMAE) at our community‐based Comprehensive Stroke Center between April 2019 and November 2024. Clinical failure was defined as hematoma reaccumulation or neurological deterioration requiring unplanned rescue surgery during the initial admission or postprocedurally, with ≥2 weeks of clinical follow‐up. Radiological failure was defined as <50% reduction in maximal hematoma thickness on the last available follow‐up CT scan, with ≥2 weeks of imaging follow‐up. Associations were assessed using chi‐squared tests, with significance set at α=0.01 (99% confidence interval). Results We included 140 patients. Median hematoma thickness and midline shift at presentation were 15 mm and 7 mm, respectively. Hematoma locations were frontoparietal (57%, n=80), entire convexity (36%, n=50), frontotemporal (3.5%, n=5), and temporo‐occipital (3.5%, n=5). At baseline, 36% (n=50) were on antiplatelets, 21% (n=30) on anticoagulants, 9% (n=12) on both, and 34% (n=48) on neither. Treatment strategies were: standalone embolization (59%, n=83), embolization after failed/prior surgical evacuation (6%, n=8), and embolization with concurrent surgical evacuation (35%, n=49). Unilateral MMAE was performed in 47% (n=66) and bilateral in 53% (n=74). Technical success was achieved in all cases (100%). Procedural complications occurred in 3% (n=4): minor ischemic stroke (1.4%, n=2), major ischemic stroke (0.7%, n=1), and hemorrhagic conversion (0.7%, n=1). Clinical treatment failure requiring rescue surgery before discharge occurred in 12.8% (n=18): craniotomy with subdural drain (6%, n=9), burr hole (5%, n=7), and repeat MMAE (2%, n=2). Post‐discharge rescue surgery was required in 2.8% (n=4): craniotomy with subdural drain (1.4%, n=2), burr hole (0.7%, n=1), and repeat embolization (0.7%, n=1). Mean imaging follow‐up was 245 days. Mean final cSDH thickness was 6.4 mm, representing an average reduction of 11 mm. Radiographic success occurred in 81.25% (n=39) of patients not on antithrombotics χ 2 =12.11, p=0.0005. Radiological failure occurred in 36% (n=18) of patients on antiplatelets χ 2 =22.39, p=2.22e‐06, 50% (n=15) on anticoagulants χ 2 =48.4, p=3.47e‐12, and 58% (n=7) on both χ 2 =71.85, p=2.31e‐17. Conclusion Baseline antiplatelet and anticoagulant use may influence both radiographic and clinical outcomes after MMAE for cSDH, highlighting the importance of individualized treatment strategies. While these findings provide valuable insight, large‐scale randomized controlled trials are needed to confirm efficacy and refine patient selection criteria.