The effect of head position as a nonpharmacological therapy on acute ischemic stroke (AIS) remains inconclusive. Recent HOPES2 (Head dOwn-Position for acutE moderate ischemic Stroke with large artery atherosclerosis) suggest the safety, feasibility, and potential benefit of the head-down position (HDP) in acute ischemic stroke. The current study aims to investigate the efficacy and safety of HDP in acute moderate ischemic stroke patients with large artery atherosclerosis.

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.