Trendelenburg Position for Acute Anterior Circulation Ischemic Stroke With Large Artery Atherosclerosis Etiology (HOPES 3)

Inclusion Criteria: * Age ≥ 18 years old * Acute ischemic stroke confirmed by NCCT or MRI; * Moderate neurologic deficit (6≤ NIHSS ≤ 16) within 24 hours of onset, or progressing from mild (NIHSS ≤ 5) to moderate neurologic deficit (6≤ NIHSS ≤ 16) within 24 hours, requiring ≥ 4 point increase in NIHSS score although the onset time is beyond 24 hours; * Probable large artery atherosclerosis etiology based on the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria (responsible artery stenosis ≥ 50% or occlusion); * Anterior circulation stroke (internal carotid artery, M1 or M2 of middle cerebral artery); * First stroke onset or past stroke without obvious neurological deficit (mRS≤2); * Signed informed consent. Exclusion Criteria: * Pre-stroke disability (mRS≥3); * Patients with disturbance of consciousness; * Patients who plan to undergo or have completed thrombolysis or mechanical thrombectomy; * Hemorrhagic stroke or combined ischemic and hemorrhagic stroke; * Serious comorbidity, such as liver or kidney insufficiency, malignant tumor, etc; * Other stroke etiologies, such as cardiogenic embolism, arteritis, arterial dissection, moyamoya disease, etc; * Previous history of intracerebral hemorrhage within 1 year; * Any contraindication to head-down position (e.g. active vomiting, pneumonia, uncontrolled heart failure); * Planned carotid or intracranial revascularization within 3 months; * Severe uncontrolled hypertension (systolic blood pressure over 180mmHg or diastolic blood pressure over 100 mmHg); * Cardiac insufficiency (NYHA Class ≥II); * Pregnant or lactating women; * Comorbidity with other serious diseases; * Participating in other clinical trials within 3 months; * Patients not suitable for the study considered by researcher.