Thrombectomy for Acute Stroke Due to Medium Vessel Occlusion Across Perfusion Mismatch Profiles

Importance Recent trials have not demonstrated a benefit of endovascular thrombectomy (EVT) over medical therapy in acute stroke due to medium vessel occlusion (MeVO). However, it remains uncertain whether selected patients with favorable perfusion may benefit from EVT. Objective To investigate the association between perfusion mismatch profiles and functional outcomes in MeVO stroke and to determine whether these profiles modify the effect of EVT. Design, Setting, and Participants This study was a post hoc analysis of ESCAPE-MeVO (Endovascular Treatment to Improve Outcomes for Medium Vessel Occlusion), a multicenter randomized clinical trial conducted in North America, Europe, and the United Kingdom between April 2022 and June 2024, with a 90-day follow-up. Trial participants included patients with acute MeVO stroke presenting within 12 hours from last known well and evidence of salvageable brain tissue. This analysis included only patients with interpretable baseline perfusion imaging. Data were analyzed from March to July 2026. Interventions Randomization to EVT plus usual care vs usual care alone. Main outcomes and measures The primary outcome was the 90-day ordinal modified Rankin Scale (mRS) score. Secondary outcomes included 24-hour follow-up infarct volume and 90-day mRS score of 0 to 1 and 0 to 2. Perfusion mismatch ratio and volume were defined as the ratio and difference between the critically hypoperfused area and the ischemic core, with volume thresholds defined by site-specific postprocessing software. Results Of 530 enrolled patients, 309 (58.3%) had available baseline perfusion imaging and were included in this study (EVT: n = 146; usual care: n = 163). Patient median (IQR) age was 73 (63-82) years, and 141 (45.6%) were women. Median (IQR) perfusion mismatch volume was 37.2 (22.1-57.2) mL, and the median (IQR) mismatch ratio was 6.1 (2.8-10.0). Ordinal 90-day mRS score was not associated with perfusion mismatch volume (adjusted odds ratio [AOR], 1.03 [95% CI, 0.99-1.07] per 10-mL increase) or perfusion mismatch ratio (AOR, 1.03 [95% CI, 0.97-1.09] per 1-unit increase). There was no modification of EVT effect by perfusion mismatch volume or ratio on ordinal 90-day mRS. Results were consistent across secondary outcomes and subgroups. Conclusions and Relevance In this exploratory post hoc analysis of acute MeVO stroke, perfusion mismatch profiles were not associated with functional outcomes and did not modify the effect of EVT. These findings suggest that perfusion imaging profiles based on currently used thresholds and cutoffs did not identify patients likely to benefit from EVT in the ESCAPE-MeVO trial. Trial Registration ClinicalTrials.gov Identifier: NCT05151172