Endovascular Treatment for Posterior Circulation Ischemic Stroke Post 1 Day （24 Hours）

Prior treatment

• Evidence of vascular recanalization prior to randomization
• Attempted use of a neurothrombectomy device to remove the clot prior to randomization
• Currently participating in a study involving other investigational drugs or devices

Other illness

• Hemorrhage on CT or MRI
• Based on the judgment of the treating physician, the patient is considered unlikely to benefit from the trial (e.g., advanced dementia, severe pre-stroke disability (mRS ≥ 2), or high risk of early mortality)
• Major comorbidities that may interfere with outcome assessment and follow-up (e.g., severe heart failure, renal failure, etc.).
• Uncontrolled seizures at the time of stroke onset, if they interfere with obtaining an accurate baseline NIHSS
• Posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS) \< 6 on non-contrast CT or CT angiography source images or MR with diffusion-weighted imaging
• Severe, persistent hypertension (systolic blood pressure \> 220 mmHg or diastolic blood pressure \> 120 mmHg)
• Known allergies to iodine, heparin, anesthetics, or other explicit contraindications to the endovascular treatment procedure
• Other serious, progressive, or end-stage diseases (as determined by the investigator) or a life expectancy of less than 6 months
• Any other conditions that the investigator believes may interfere with the endovascular procedure or pose significant risk to the subject during the procedure

Lab values

• Baseline platelet count \<50,000/uL
• Known hereditary or acquired bleeding disorders, coagulation factor deficiencies, or recent oral anticoagulant therapy with an International Normalized Ratio (INR) \> 3

Other

• Complete cerebellar infarct with significant mass effect and compression of the fourth ventricle,or bilateral thalamic infarction on CT or MRI
• Suspected purulent embolism, with a suspicion of bacterial endocarditis
• Pregnancy
• Evidence of intracranial tumor on CT or MRI (excluding meningioma)
• CTA/MRA showing excessive tortuosity of the cervical vessels, which may interfere with endovascular treatment
• Suspicion of aortic dissection based on medical history and CTA/MRA findings

• Age ≥ 18 years old
• Baseline NIHSS score of 4 or higher, maintained prior to randomization
• Stroke onset or more than 24 hours since the last known good state, but within 14 days
• CTA/MRA/DSA confirmed occlusion of the responsible vessel in basilar artery or intracranial segments of both vertebral arteries (V4)
• Modified Rankin Scale (mRS) score of 0 or 1 pre-stroke
• The subject or their legally authorized representative has signed the informed consent form for the study