Endovascular therapy in acute anterior circulation large vessel occlusive patients with low NIHSS (ORIENTAL ENDOLOW): protocol of a multicenter randomized clinical trial

Introduction Mechanical thrombectomy has been well-established as the standard of care treatment for patients with moderate to severe acute ischaemic stroke secondary to large vessel occlusion. However, the clinical value of endovascular treatment (EVT) in patients presenting with minor stroke and low baseline National Institutes of Health Stroke Scale scores remains incompletely defined, with limited high-quality clinical evidence. This protocol outlines the methodology of a randomized trial designed to evaluate whether EVT combined with best medical therapy (BMT) achieves superior functional outcomes relative to BMT alone among patients with minor stroke. Methods and analysis Eligible patients with acute minor anterior circulation ischaemic stroke and confirmed large vessel occlusion (n=264) will be randomized via a computer generated block randomization sequence to receive either EVT plus BMT (intervention arm) or BMT alone (control arm). The primary efficacy outcome is the proportion of participants achieving excellent functional recovery, defined as a modified Rankin Scale score of 0 or 1 at 90 days. Primary safety outcomes comprise symptomatic intracranial haemorrhage within 48 hours after randomization (classified according to Heidelberg criteria) and all cause mortality at 90 days. Participants will be considered eligible if they satisfy all of the following inclusion criteria: (1) enrolment within 24 hours of stroke symptom onset or time last known well; (2) baseline NIHSS score of 2 - 5 accompanied by at least one focal neurological deficit (including altered consciousness, facial palsy, limb weakness, aphasia or hemispatial neglect); (3) angiographically confirmed acute occlusion of the intracranial internal carotid artery, the M1 segment of the middle cerebral artery, or a dominant M2 branch; (4) a hypoperfusion volume (Tmax >6s) [≥] 50mL on computed tomography or magnetic resonance perfusion imaging. Both intention to treat and per protocol analyses will be undertaken, and potential sources of heterogeneity in treatment effect magnitude will be explored. Ethics and Dissemination This study was approved by the ethnic committee from the First Affiliated Hospital of Wannan Medical University (2023-IRB90). The findings of this study will be disseminated through publication in peer-reviewed journals. Registration URL:https://www.clinicaltrial.gov; Unique identifier: NCT06143488.