Middle meningeal artery embolisation (MMAe) involving microparticles—as opposed to liquid embolic agents, glues or coils—did not lead to a statistically significant reduction in six-month chronic subdural haematoma (cSDH) recurrence compared to standard medical care, as per results from the recently published EMPROTECT randomised controlled trial (RCT).
Nevertheless, outlining their findings in the Journal of the American Medical Association (JAMA), Eimad Shotar (Pitié-Salpêtrière Hospital, Paris, France) et al posit that “the magnitude of the effect estimate is consistent with other recent trials, including some that demonstrated the benefit of MMAe with non-adhesive liquid embolic agents”, alluding to the EMBOLISE, STEM and MEMBRANE RCTs presented throughout 2024.
The EMPROTECT authors therefore conclude that “these findings considered together may inform future studies and potential use of this therapeutic approach [MMAe] for cSDH management”.
EMPROTECT was designed with the goal of assessing the efficacy of MMAe via 300–500μm Embosphere particles (Merit Medical) in reducing risks of CSDH recurrence at six months—as compared to standard medical care—in patients who had undergone prior surgery and were at a high risk of haematoma recurrence.
This multicentre, open-label RCT with blinded-endpoint assessment included a total of 342 patients (median age, 77 years; 80.1% male) who underwent an operation for cSDH recurrence or a first cSDH episode at high risk of recurrence between July 2020 and March 2023 across 12 French centres, with the final follow-up taking place in November 2023. Patients were randomised 1:1 to receive microparticle-based MMAe plus medical management within seven days of surgery (intervention group, n=171) or medical management alone (control group, n=171).
The study’s primary endpoint was the rate of cSDH recurrence at six months—assessed by an independent, blinded adjudication committee—while notable secondary endpoints included rates of repeat surgery for homolateral cSDH recurrence during the six-month follow-up period and complications relating to the embolisation procedure.
Shotar et al note in their JAMA report that 90.1% (n=308) of randomised patients completed the study and, across this population, the primary endpoint of six-month cSDH recurrence was observed at a rate of 14.8% in the MMAe group (n=24/162) versus 21% in the control group (n=33/157). The authors also relay a post-imputation odds ratio of 0.64 for this finding (95% confidence interval [CI], 0.36–1.14) and an adjusted absolute difference of −6% (95% CI, −14% to 2%; p=0.13), meaning the between-group disparity did not reach statistical significance.
Additionally, the two groups did not significantly differ regarding any of the secondary endpoints. Repeat surgery was performed in 4.3% and 8.3% of patients in the MMAe and control groups, respectively (p=0.14), while minor and major embolisation procedure-related complications occurred in 1.8% and 0.6% patients, respectively.
Initial data from the EMPROTECT RCT were first presented by Shotar at last year’s European Society of Minimally Invasive Neurological Therapy (ESMINT) congress (4–6 September 2024, Marseille, France), with the speaker highlighting the potential impact different embolisation approaches like liquid embolics or particles may have on the efficacy of cSDH treatments, also remarking that there is a “very poor definition” of cSDH outcome measures in the current literature.
“The disease itself does not have a formal definition—so, in most studies, the definition of a cSDH patient is left to the discretion of the investigators,” Shotar commented, adding that an equally poor definition of what constitutes ‘at-risk’ cSDH may have led to those deemed to be high-risk patients in EMPROTECT failing to demonstrate a greater recurrence rate compared to patients in other trials with no such inclusion criteria.
