Rescue Endovascular Therapy for Progressive Acute Mild Ischemic Stroke With Large Vascular Occlusion

Inclusion Criteria: General Inclusion Criteria： * Age ≥ 18 years； * Presenting with symptoms consistent with an AIS and the initial NIHSS score \<6 points； * Symptom progression within 7 days of first onset； * Randomization can be finished \> 24 hours of stroke onset (stroke onset time is defined as last known well time)； * Symptom progression to randomization time ≤ 24 hours； * NIHSS score before randomization ≥ 6 points； * Informed consent signed. Specific Neuroimaging Inclusion Criteria * CTA or MRA proved occlusion of Internal Carotid Artery (ICA) terminal or M1 segment of Middle Cerebral Artery; * The progression of symptoms is caused by the recurrence of cerebrovascular diseases in the same vascular region, or the pathogenesis is caused by reduced blood flow perfusion; * NCCT ASPECTS before randomization ≥ 6 * CTP or MRP assessment shows low perfusion in the target vessel area, and meets the following criteria: core infarction volume is less than 50ml, mismatch rate is greater than or equal to 1.8, and mismatch volume is greater than 15ml. Exclusion Criteria: * Pre-stroke mRS score \>1; * Imaging confirms the progression of symptoms caused by intracranial hemorrhage, brain edema, or other clear causes; * The target vessel may have factors that may prevent it from completing endovascular treatment, such as a diameter less than 1.5mm, a tortuous vascular pathway, difficulty in reaching the target position with instruments, or difficulty in recovery; * Severe stenosi…