Rationale: Mechanical thrombectomy (MT) has become the standard of care for patients with acute ischemic stroke secondary to large vessel occlusion (LVO) of the anterior circulation. Conversely, its benefit in patients with National Institutes of Health Stroke Scale (NIHSS) score ⩽ 5 is unproven.
Aim: To demonstrate the superiority of immediate MT plus best medical treatment (BMT) compared to BMT (with secondary MT in case of deterioration) for increasing the rate of modified Rankin Scale (mRS) score ⩽ 1 at 90 days after minor stroke (NIHSS score ⩽ 5) and anterior circulation LVO.
Sample size estimates: To detect an absolute increase of 10% (80% power) in the 90-day mRS score = 0-1 rate in the MT + BMT group, by assuming an mRS score = 0-1 rate of 60% in the BMT group and by considering two interim efficacy/futility analyses (after study completion by 274 and 548 patients), 824 patients must be included by 36 centers in France, Spain, and the USA.
Methods and design: MOSTE is an international, multicenter, prospectively randomized into two parallel (1:1) arms, open-label, with blinded endpoint trial. Eligibility criteria are diagnosis of acute ischemic stroke within 23 h of last-seen-well, NIHSS score ⩽ 5, and LVO in the anterior circulation (intracranial internal carotid artery, M1 or M1-M2 segment of the middle cerebral artery).
Study outcomes: The primary endpoint is the rate of excellent outcome at day 90 (mRS score = 0-1). Secondary endpoints include the rates of 90-day mRS score = 0-2 and score = 0, NIHSS score change, secondary MT, revascularization and infarct volume growth at 24 h, and quality of life and cognitive function at day 90. Safety outcomes (90-day all-cause mortality, procedural complications, symptomatic intracerebral hemorrhage, and rapid NIHSS score worsening) are recorded.
Discussion: The MOSTE trial will determine MT efficacy and safety in patients with minor stroke and LVO in the anterior circulation.
Trial registration: MOSTE Trial. NCT03796468.
Keywords: Acute stroke therapy; NIHSS 0–5; clinical trial; ischemic stroke; large vessel occlusion; mechanical thrombectomy.