Inclusion Criteria1. Acute ischemic stroke due to basilar artery occlusion within 6-24 hours from symptom onset，where patient is ineligible for IV thrombolytic treatment or the treatment is contraindicated (e.g., subject presents beyond recommended time from symptom onset), or where patient has received IV thrombolytic therapy without recanalization.
2. Occlusion of the basilar artery (TIMI 0-1) as evidenced by CTA, MRA or angiogram.
3. Age ≥18 and ≤80 years.
4. Baseline NIHSS score obtained prior to randomization ≥10.
5. No significant pre-stroke disability (mRS ≤1).
6. Subject treatable within 24 hours from symptoms onset or time last seen at baseline (i.e., subjects who have stroke symptoms upon awakening will be considered to have their "onset" at beginning of sleep; subjects who are found with new stroke symptoms and are unable to communicate the actual time of symptoms onset will be considered to have their "onset" at the last time they were seen well). Treatment initiation is defined as groin or other access site puncture. Symptoms onset include vertigo, diplopia, midline ataxia, visual loss, sensory or motor deficits.
7. Anticipated life expectancy of at least 1 year.
8. Informed consent obtained from Subject or acceptable Subject Surrogate.
Exclusion Criteria1. Known hemorrhagic diathesis, coagulation factor deficiency, or oral anticoagulant therapy with International Normalized Ratio (INR) ＞3.0
2. Baseline platelet count ＜50000/µL
3. Baseline blood glucose of ＜50mg/dL or ＞400mg/dL.
4. Severe, sustained hypertension (systolic blood pressure ＞220 mm Hg or diastolic blood pressure ＞110 mm Hg) Note: If the blood pressure can be successfully reduced and maintained at the acceptable level using local treatment guidelines recommended medication (including iv antihypertensive drips), the patient can be enrolled.
5. Intubated patients for transfer could be randomized only in case an NIHSS is obtained by a neurologist prior transportation.
6. Seizures at stroke onset which would preclude obtaining a baseline NIHSS.
7. History of life threatening allergy (more than rash) to contrast medium.
8. Subjects who have received iv recombinant tissue plasminogen activator （rt-PA）treatment beyond 4.5 hours from the beginning of the symptoms.
9. Patients with acute stroke within the first 48 hours after percutaneous cardiac, cerebrovascular interventions and major surgery (beyond 48h they should be randomized or excluded if poor medical conditions)
10. Renal insufficiency with creatinine ≥3 mg/dL.
11. Woman of childbearing potential who is known to be pregnant or lactating or who has a positive pregnancy test on admission.
12. Subject participating in a study involving an investigational drug or device that would impact this study.
13. Cerebral vasculitis.
14. Patients with a pre-existing neurological or psychiatric disease that would confound the neurological or functional evaluations, mRS score at baseline must be ≤1. This excludes patients who are severely demented, require constant assistance in a nursing home type setting or who live at home but are not fully independent in activities of daily living (toileting, dressing, eating, cooking and preparing meals, etc.)
15. Unlikely to be available for 1 year follow-up (e.g. no fixed home address, visitor from overseas).
16. Posterior circulation ASPECTS ＜6 and Pons-midbrain-index of ≥3.
17. CT or MR evidence of hemorrhage (the presence of microbleeds is allowed).
18. Complete cerebellar infarct on CT or MRI with significant mass effect and compression of the 4-th ventricle.
19. Complete thalamic infarction on CT or MRI.
20. Evidence of vertebral occlusion, high grade stenosis or arterial dissection in the extracranial or petrous segment of the vessel that cannot be treated or will prevent access to the intracranial clot or excessive tortuosity of cervical vessels precluding device delivery/deployment.
21. Subjects with occlusions in multiple vascular territories ( anterior circulation and posterior circulation).
22. Evidence of intracranial tumor (except small meningioma).