Despite markedly reducing chronic subdural haematoma (cSDH) recurrence without significantly increasing overall adverse events, adjunctive middle meningeal artery embolisation (MMAE) was not associated with significant improvements in functional outcomes or mortality in an updated meta-analysis of randomised controlled trials (RCTs) investigating this procedure.
Nonetheless—writing in the Journal of Stroke and Cerebrovascular Diseases—a research team led by corresponding author Tallal M Hashmi (Rawalpindi Medical University, Rawalpindi, Pakistan) states that “these findings support adjunctive MMAE as an effective and safe strategy for improving disease control in patients undergoing surgical treatment for cSDH”.
Since early 2024, several RCTs have produced positive findings indicating that MMAE is a promising adjunctive treatment for cSDH, resulting in the publication of a Society of Vascular and Interventional Neurology (SVIN)-led consensus statement advising that the approach “may become a standard of care” for the management of selected cSDH patients. However, as noted by Hashmi et al, the overall efficacy and safety of adjunctive MMAE compared to surgery alone “remains uncertain”.
As such, they performed a systematic database search for RCTs comparing adjunctive MMAE plus surgical evacuation versus surgical evacuation alone in cSDH patients, with their primary outcome of interest being haematoma recurrence. Eight RCTs—the large-scale EMBOLISE, STEM, EMMA-Can and MEMBRANE trials, as well as four smaller studies conducted across France, Australia, the USA, and Brazil—were included for analysis. The researchers relay that these RCTs comprised 1,459 cSDH patients, of whom 712 received adjunctive MMAE after surgical evacuation, while 747 underwent surgical evacuation alone. Sample sizes ranged from 35 to 400 participants, with follow-up durations varying from three to 18 months. The mean age of participants ranged from 64 to 77 years, and roughly two-thirds of the overall study population were men.
Hashmi et al’s pooled analysis found recurrence rates of 4.6% with MMAE versus 13.9% without—thus demonstrating a significant reduction in the chances of recurrence with adjunctive MMAE compared to surgery alone (odds ratio [OR], 0.31; p=0.004; I²=17.1%), corresponding to an absolute risk reduction of 9.3% and a number needed to treat of 11 to prevent one recurrence. This overall effect estimate remained stable upon ‘leave-one-out’ sensitivity analysis, with no individual study materially influencing the pooled effect, while additional sensitivity analyses excluding trials with higher recurrence rates in their surgery-only groups also revealed findings that were consistent with the primary analysis.
All three of the researchers’ secondary outcomes of interest were shown to be comparable between study groups, however. Their pooled analysis demonstrated no statistically significant difference in the odds of all-cause mortality (OR, 0.91; p=0.86; I²=49.4%), with 29 deaths occurring in the adjunctive MMAE group versus 33 with surgery alone across the seven RCTs with sufficient data available. Similarly, a good functional outcome—defined as a modified Rankin scale (mRS) score of 0–2—was achieved by 244 of 326 patients in the MMAE group and 253 of 336 patients in the surgery-alone group across four RCTs, with no statistically significant difference between the groups (OR, 1.23; p=0.72; I²=62%). Finally, across the six RCTs with sufficient data available, there were comparable rates of overall adverse events (OR, 1.02; p=0.96; I²=63%), with 108 and 113 occurring in the MMAE and surgical groups, respectively.
“Similar observations have been reported in prior studies, highlighting a persistent disconnect between anatomical success and functional recovery in patients with cSDH,” Hashmi et al write, discussing their findings in greater detail.
They go on to outline multiple factors that may explain said findings, including the fact that cSDH patients are typically elderly and frequently have substantial comorbidity burdens, baseline frailty, and underlying neurodegenerative conditions that independently influence recovery and survival, “thereby limiting the impact of recurrence prevention on functional status”. Similarly, the authors add, mortality after cSDH treatment is relatively infrequent and is often driven by comorbid medical illnesses rather than haematoma recurrence itself, diminishing the ability of recurrence reduction to influence survival outcomes. They also posit that functional recovery may “lag behind” radiographic resolution, meaning the relatively short follow-up periods of the included trials could be insufficient in capturing the long-term clinical benefits associated with improved haematoma resolution and reduced recurrence.
“Beyond its clinical efficacy, adjunctive MMAE may offer important practical and economic advantages,” Hashmi et al continue. “As recurrence prevention remains a key unmet need in cSDH management, the combination of improved disease control and reduced need for subsequent procedures may ultimately enhance the cost-effectiveness of care. However, formal cost-effectiveness analyses incorporating long-term follow-up, quality-of-life measures and downstream healthcare expenditures are needed to better define the economic value of adjunctive MMAE.”
