Abstract Number: Esoc2026a2478 Escape-Mevo Trial 1 Year Outcomes

Abstract Background It is uncertain if the large effect size of endovascular thrombectomy (EVT) for stroke due to large vessel occlusion applies to stroke caused by medium vessel occlusions (MeVO). Two published trials examining EVT for MeVO were neutral. Methods In a multicenter, prospective, randomized, open label trial with blinded endpoint evaluation, patients with acute ischemic stroke due to MeVO presenting within 12 hours from last known well and favorable baseline non-invasive brain imaging were randomly allocated to usual care or EVT plus usual care. A key secondary outcome was the modified Rankin Score at 1 year. Results 530 patients from 5 countries were enrolled between April 2022 and June 2024. A majority (85%) had primary occlusions in a middle cerebral artery branch; 255 patients were randomized to EVT plus usual care, and 275 patients to usual care only. One patient withdrew consent immediately after randomization. At one year, 23 patients were lost to follow-up. Among 506 patients, 110/248 (44%) and 124/258 (48%) had a mRS 0-1 at 1 year adjRR = 0.90, CI95 0.75-1.07, p=0.236. Overall mortality was higher at 1 year in the treatment group 50/248 (20%) vs. 31/258 (12%) adjRR = 1.89, CI95 1.28- 2.80, p=0.010. Conclusions Endovascular treatment as compared to usual care for acute ischemic stroke due to medium vessel occlusion within 12 hours from last known did not improve outcomes at 1 year. Trial registration number: clinicaltrials.gov identifier NCT05151172 Conflict of interest Funding: Grants to the University of Calgary from the Canadian Institutes for Health Research and from Medtonic LLC