Endovascular therapy versus best medical management in distal medium middle cerebral artery acute ischaemic stroke: a multinational multicentre propensity score-matched study

Background: The efficacy of endovascular treatment (EVT) in acute ischaemic stroke due to distal medium vessel occlusion (DMVO) remains uncertain. Our study aimed to evaluate the safety and efficacy of EVT compared with the best medical management (BMM) in DMVO. Methods: In this prospectively collected, retrospectively reviewed, multicentre cohort study, we analysed data from the Multicentre Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy registry. Patients with acute ischaemic stroke due to DMVO in the M2, M3 and M4 segments who underwent EVT or received BMM were included. Primary outcome measures comprised 10 co-primary endpoints, including functional independence (mRS 0-2), excellent outcome (mRS 0-1), mortality (mRS 6) and haemorrhagic complications. Propensity score matching was employed to balance the cohorts. Results: Among 2125 patients included in the primary analysis, 1713 received EVT and 412 received BMM. After propensity score matching, each group comprised 391 patients. At 90 days, no significant difference was observed in achieving mRS 0-2 between EVT and BMM (adjusted OR 1.00, 95% CI 0.67 to 1.50, p>0.99). However, EVT was associated with higher rates of symptomatic intracerebral haemorrhage (8.4% vs 3.0%, adjusted OR 3.56, 95% CI 1.69 to 7.48, p<0.001) and any intracranial haemorrhage (37% vs 19%, adjusted OR 2.61, 95% CI 1.81 to 3.78, p<0.001). Mortality rates were similar between groups (13% in both, adjusted OR 1.48, 95% CI 0.87 to 2.51, p=0.15). Conclusion: Our findings suggest that while EVT does not significantly improve functional outcomes compared with BMM in DMVO, it is associated with higher risks of haemorrhagic complications. These results support a cautious approach to the use of EVT in DMVO and highlight the need for further prospective randomised trials to refine treatment strategies.