Recent studies suggest that head-down positioning (HDP) intervention may improve outcomes in ischemic stroke. In the era of reperfusion therapy, a key protective strategy is to administer neuroprotective interventions before recanalization to reduce the loss of the ischemic penumbra, thereby salvaging more penumbral tissue after revascularization and ultimately improving clinical outcomes. Based on this concept, and considering the neuroprotective effects of HDP, the investigators hypothesize that HDP intervention prior to endovascular therapy (EVT) in patients with large vessel occlusion could improve clinical outcomes. This hypothesis is further supported by a recent clinical study (NCT03728738), which demonstrated that compared to a sitting up position (30°), a flat supine position (0°) before EVT significantly reduced the incidence of neurological deterioration prior to the procedure. Building on the above rationale, this trial aims to investigate the efficacy and safety of HDP intervention prior to EVT in patients with large vessel occlusion.