Head Down Position for Successful Recanalization of Anterior Circulation Large Vessel Occlusion (HOPES4)

Inclusion Criteria: * Age ≥ 18 * Anterior circulation large vessel occlusion who received endovascular treatment within 24 hours of stroke onset; * National Institute of Health Stroke Scale (NIHSS) ≥ 6 before endovascular treatment; * Successful recanalization (mTICI 2b-3) after endovascular treatment; * Cerebral circulation time based on DSA of the stroke side was slower than that of the healthy side after successful recanalization; * ASPECTS ≥ 6 on CT or DWI; * Absence of parenchymal hematoma on CT images done in the angio suite immediately after the procedure; * Modified Rankin Scale score before stroke onset ≤ 1; * Signed informed consent by patient or their legally authorized representative. Exclusion Criteria: * Hemorrhagic stroke: cerebral hemorrhage, subarachnoid hemorrhage; * Severe hepatic or renal dysfunction, increase in ALT or AST (more than 2 times of upper limit of normal value), increase in serum creatinine (more than 1.5 times of upper limit of normal value) or requiring dialysis; * After recanalization, severe and sustained (i.e., \> 5 minutes) uncontrolled hypertension (systolic blood pressure over 180mmHg or diastolic blood pressure over 105 mmHg) refractory to antihypertensive medication; * More than four retrieval attempts in the same vessel; * Cardiac insufficiency (NYHA Class ≥II); * Pregnancy, plan to get pregnant or during lactation; * The estimated life expectancy is less than 6 months due to other serious diseases; * Other conditions unsuitable for this clinical study assessed by researcher.