Endovascular Treatment in Acute Intracranial Distal Medium Vessel Occlusion Stroke: Study Protocol and Rationale

Background: Distal medium vessel occlusions (MeVO) account for an estimated 25% to 40% of all acute ischemic strokes. Emerging evidence from non-randomized trials suggest that endovascular thrombectomy (EVT) can achieve high rates of successful reperfusion in MeVO strokes, with a safety profile comparable to EVT for proximal arterial occlusions. These findings underscore the need for a prospective randomized clinical trial to evaluate the safety and efficacy of EVT for MeVO stroke. Objective: This trial aims to evaluate the safety and efficacy of EVT for MeVO stroke. Methods and design: Endovascular treatment in acute intracranial distal medium vessel occlusion stroke (ORIENTAL-MeVO) is an investigator-initiated, multicenter, prospective, randomized clinical trial with open-label treatment and blinded endpoint assessment (PROBE). Up to 564 eligible patients will be consecutively randomized in a 1:1 ratio to receive either EVT or standard of care over a period of 2 years in over 50 comprehensive stroke centers in China. Outcomes: The primary outcome is a shift in the distribution of the modified Rankin Scale at day 90s with levels 5-6 combined (mRS; 0, 1, 2, 3, 4, 5-6). Primary safety endpoints include symptomatic intracerebral hemorrhage at 24 hours and mortality at 90 days.