275 Adjunctive Middle Meningeal Artery Embolization for Subdural Hematoma: Clinical and Radiographic Results of the EMBOLISE Trial

INTRODUCTION: Subacute/chronic subdural hematomas are common and frequently recur after surgical evacuation. METHODS: EMBOLISE is a multicenter, prospective, randomized, interventional, adaptive design trial of middle meningeal artery embolization combined with surgical evacuation of the subdural clot compared to surgery only. The primary endpoint was the rate of hematoma recurrence/progression requiring repeat surgical drainage RESULTS: A total of 197 patients were assigned to the treatment group and 203 to the control group. The absolute risk of the primary endpoint was 4.1% [1.8%, 7.8%] in the embolization group vs. 11.3% [7.3%, 16.5%] in the surgery only group (relative risk 0.36 [0.11, 0.80], P = 0.008). The secondary endpoint of deterioration in neurologic function (defined as having mRS < 3 at baseline and = 3 at 90 days or having = 3 at baseline and having an increase of = point at 90 days) occurred in 11.9% vs. 9.8%, respectively. No adverse events within 90 days were related to Onyx. The 30- and 90-day rate of serious adverse events, including death, were similar in both arms. Radiographic data is forthcoming and will be presented at the CNS meeting. CONCLUSIONS: In patients with symptomatic subacute/chronic subdural hematoma requiring surgical drainage, adjunctive middle meningeal artery embolization was associated with a lower rate of hematoma recurrence/progression requiring repeat surgical drainage, without any increase in adverse events. Core-lab adjudicated analysis demonstrates favorable radiographic responses in patients who received MMA embolizaation, correlating with the clinical results.