Rescue Endovascular Treatment After Neurological Deterioration in Initially Mild Basilar Artery Occlusion in an Extended Time Window

A prospective, multicenter, open-label, blinded-endpoint, randomized controlled trial to evaluate whether best medical management (BMM) combined with endovascular therapy (EVT) improves neurological outcomes compared to BMM alone in patients with progressive acute mild ischemic stroke due to basilar artery occlusion within an extended time window.

Inclusion Criteria: 1. Age ≥18 years. 2. Initially mild ischemic stroke, defined as an initial NIHSS score \2. 3. Factors in the target vessel that are expected to prevent completion of endovascular treatment. 4. Concurrent anterior and posterior circulation strokes. 5. Prior imaging confirmed or investigator-assessed chronic basilar artery occlusion. 6. Presence of untreated intracranial aneurysms, intracranial tumors (except small meningiomas), or intracranial vascular malformations. 7. Intracranial hemorrhage within the past 6 months, including parenchymal brain hemorrhage, intraventricular hemorrhage, or subarachnoid hemorrhage. 8. Gastrointestinal or urinary tract bleeding, acute myocardial infarction, cranial trauma, or major surgery within the past month. 9. Presence of active bleeding, coagulation disorders, or uncorrectable bleeding tendencies. 10. Platelet count \2 during anticoagulation therapy (irreversible). 11. Severe heart, liver, or kidney dysfunction or other severe systemic late-stage diseases. 12. Known allergy to iodine contrast agents or other treatment-related drugs. 13. Medically uncontrolled refractory hypertension (defined as persistent systolic blood pressure \>185 mmHg or diastolic blood pressure \>110 mmHg) (Note: Participants can be included if their blood pressure is controllable with medication and maintained at an acceptable level). 14. Uncontrollable blood glucose \22.2 mmol/L. 15. Pregnancy or breastfeeding. 16. Life expectancy \