Background and purpose Chronic subdural hematoma (cSDH) affects approximately 20 per 100,000 individuals annually, with surgical recurrence rates of 10–20%. Middle meningeal artery embolization (MMAE) has emerged as a promising minimally invasive treatment, but the optimal timing remains unclear. We evaluated the association between MMAE timing and radiological and functional outcomes in cSDH. Methods We conducted a retrospective multicenter international cohort study across 33 centres, including patients who underwent MMAE for cSDH between January 2018 and December 2024. Patients were stratified by timing from diagnosis: Q1 (≤1 day), Q2 (2 days), Q3 (3–6 days), and Q4 (>6 days). The primary composite endpoint required radiological success (hematoma thickness <5 mm at 1–3 months), absence of emergency surgical evacuation, and either functional improvement or good functional outcome (modified Rankin Scale 0–2). Propensity score matching compared Q1 and Q4. Results Of 1,781 patients screened, 908 met inclusion criteria. Mean age was 73.7 ± 12.2 years, and 70.9% were female. Early embolization (Q1) achieved the primary composite endpoint more frequently than delayed embolization (Q4), with concordant improvements in radiological and functional components and no difference in rescue surgery. Good functional outcome was achieved in 76.0% of Q1 patients versus 63.8% in Q4 (absolute difference, 12.2%; P=.003; number needed to treat approximately 8). Hospital length of stay was 21.0 days shorter in Q1 versus Q4 (P<.001), partly attributable to the timing definition. In 174 propensity score-matched pairs, early embolization was associated with higher odds of achieving the primary endpoint (odds ratio, 6.41; 95% confidence interval, 3.29–12.48; P<.001), with pronounced benefit among patients receiving antithrombotic therapy (odds ratio, 8.06; 95% confidence interval, 3.65–17.80). Conclusions Early MMAE (≤1 day from diagnosis) was overall associated with better outcomes compared with delayed intervention, particularly among patients receiving antithrombotic therapy. Prospective confirmation is warranted.
DeMessie et al. (Fri,) studied this question.