Abstract 094: Embolization of middle meningeal artery for subacute and chronic subdural hematomas using liquid embolic materials and coils: a multistudy comparison
Authors: Penagos J. Carrion , Karar L. , Chahine A. , Morsi R. , Baskaran A. , Thind S. , Kothari S. , Desai H. , Metman O. Verhagen , Coleman E. , Brorson J. , Siegler J. , Prabhakaran S. , Mansour A. , Kass‐Hout T. 
Published: January 2025

Introduction
Chronic subdural hematomas (SDH) are common in older adults due to increased risks of falls, cerebral atrophy, and antithrombotic therapy, leading to higher bleeding risks. Current randomized clinical trials are evaluating the safety and efficacy of middle meningeal artery (MMA) embolization for chronic SDH. These trials, such as EMBOLISE, MAGIC‐MT, and STEM, have reported preliminary promising results using different embolic agents. This study examines the safety and efficacy of MMA embolization using liquid embolic materials and coils at a single institution, comparing outcomes with the aforementioned trials.

Methods
We conducted a retrospective review of 66 patients who underwent MMA embolization for subacute and chronic SDH at a single institution from February 2021 to March 2024. Data were collected from electronic medical records, including demographics, clinical data, imaging, procedural details, use of antiplatelet or anticoagulation medications, and outcomes at discharge and follow‐up. Patients aged 18 or older with subacute or chronic SDH who underwent MMA embolization were included. Follow‐up assessments were conducted at multiple intervals post‐procedure. Descriptive statistics were used for data analysis.

Results
The median age of the cohort was 71 years, with a predominance of males (64.71%) and African Americans (54.90%). Eighteen patients had prior SDH interventions, and 62.75% were on antithrombotic therapy before diagnosis. The median time from symptom onset to diagnosis was one day, with most SDHs being traumatic (60.78%). Elective MMA embolizations were performed in 64.71% of cases, primarily using a femoral approach. N‐butyl cyanoacrylate (n‐BCA) was used in 97.37% of procedures, and coils in 27.63%. Complications were rare, with two cases (3.92%) of MMA rupture and access site hematoma. The technical success rate was 97.37%.
The median hospital stay was seven days, with most patients discharged home (70.59%). The in‐hospital mortality rate was 1.96%, with seven post‐discharge deaths unrelated to MMA embolization or SDH. The median follow‐up duration was 130 days, with two patients (3.92%) requiring repeat MMA embolization and three (5.88%) needing SDH evacuation.
Compared to EMBOLISE, MAGIC‐MT, and STEM trials, our study showed a recurrence rate of 9.8% for all patients, with 6.45% in the MMA embolization alone group and 15% in the surgery with adjunctive MMA embolization group. EMBOLISE reported a 4.10% recurrence rate with surgical evacuation with adjunctive MMA embolization, MAGIC‐MT showed 1.90% recurrence with MMA embolization alone and 4.70% with surgery and adjunctive MMA embolization, and STEM found 19.10% recurrence with MMA embolization alone and 12.30% with surgery with MMA embolization.

Discussion
Our study suggests that selective distal embolization using n‐BCA is effective, with a low complication rate. Distal embolization may prevent cranial nerve injuries and strokes associated with proximal embolizations. The ongoing trials will provide further insights into optimal embolization sites and agents, and the timing for restarting anticoagulation.

Conclusion
MMA embolization using liquid embolic materials and coils is a promising treatment for subacute and chronic SDH, with low recurrence and complication rates. Comparison with current trials indicates favorable outcomes. Further research is needed to refine embolization techniques and optimize patient management strategies, potentially revolutionizing chronic SDH treatment.