ABSTRACT NUMBER: ESOC2026A1896 CLOSABLE: A CORE LAB ADJUDICATED ANALYSIS OF STANDALONE COIL EMBOLIZATION OF THE MIDDLE MENINGEAL ARTERY USING SWIFTPAC COILS FOR TREATMENT OF CHRONIC SUBDURAL HEMATOMA

Abstract Background and aims Distal penetration of the chronic subdural hematoma (cSDH) microvascular bed with liquid embolics or particles is traditionally considered the goal of middle meningeal artery embolization (MMAe). However, emerging evidence suggests that coil-only embolization may achieve comparable efficacy with favorable safety. Most existing data rely on self-reported outcomes. We present a multicenter, core-lab–adjudicated analysis of stand-alone coil-based MMAe using Penumbra SwiftPAC coils. Methods A multicenter registry of SwiftPAC MMAe cases was reviewed. Patients treated with adjunct embolics were excluded. Imaging outcomes were adjudicated by an independent core lab (New England Imaging Core Lab). The primary endpoint was rescue treatment within 180 days, defined as cSDH recurrence or growth requiring re-treatment. Secondary endpoints included changes in hematoma thickness, volume, and midline shift (MLS). Results Seventy-eight embolizations in 60 patients (mean age 73.2 ± 10.2 years; 73% male) were included. Median baseline hematoma thickness and volume were 13.3 mm and 61.9 mL; median MLS 1.8 mm. Median follow-up was 64 days. Core-lab adjudication showed median post-treatment thickness 6.1 mm, volume 12.3 mL, and MLS 0 mm, with median reductions of 48% and 76%, respectively. Complete resolution occurred in 23 cases, and ≥50% reduction in 37. No procedural complications were reported. Rescue treatment occurred in 4/55 patients (7.2%). In those without upfront surgery, ≥50% volume reduction occurred in 11/32 embolizations, with 0% rescue rate. Conclusions Core-lab–adjudicated results demonstrate that stand-alone coil MMAe yields substantial radiographic improvement, low retreatment rates, and excellent safety, supporting coils as a safe and effective primary MMAe strategy pending longer-term validation. Conflict of interest The authors report receiving grant funding from Penumbra in support of this study. Table 1 - belongs to Conclusions