Basilar Artery Occlusion Chinese Endovascular Trial in the Extended Time Window

Inclusion Criteria:

1. Posterior circulation acute ischemic stroke within 24-72 hours from symptomonset/last seen well (except for isolated vertigo), where patient is ineligible forIV thrombolytic treatment or the treatment is contraindicated (e.g., patientpresents beyond recommended time from symptom onset), or where patient has receivedIV thrombolytic therapy without recanalization.

2. Occlusion (TIMI 0-1) of the basilar artery or intracranial segments of bothvertebral arteries (V4) as evidenced by CTA/MRA/DSA.

3. Age ≥18 and ≤ 80.

4. Baseline NIHSS score obtained prior to randomization must be equal or higher than 6points.

5. No significant pre-stroke functional disability (mRS ≤ 1).

6. Patient treatable within 72 hours of symptom onset. Symptom onset is defined as thepoint in time the patient was last seen well (at baseline) if patients are unable toprovide a reliable history or the point in time when symptoms have started ifpatients can provide a reliable history.

7. Informed consent obtained from patient or authorized patient surrogate

Exclusion Criteria:

Clinical criteria

1. Known hemorrhagic diathesis, coagulation factor deficiency, or oral anticoagulanttherapy with INR > 3.0.

2. Baseline platelet count < 50000/µL.

3. Baseline blood glucose of < 50mg/dL or >400mg/dl.

4. Severe, sustained hypertension (SBP > 220 mm Hg or DBP > 110 mm Hg) NOTE: If theblood pressure can be successfully reduced and maintained below these levels usingcommonly used medications in China for these purposes (including iv antihypertensivedrips), the patient can be enrolled.

5. Patients in whom baseline NIHSS can not be obtained by a neurologist or emergencyphysician prior to sedation or intubation.

6. Seizures at stroke onset which would preclude obtaining a baseline NIHSS.

7. Serious, advanced, or terminal illness with anticipated life expectancy of less thanone year.

8. History of life threatening allergy (more than rash) to contrast medium.

9. Patients with acute stroke within the first 48 hours after percutaneous cardiac,cerebrovascular interventions and major surgery .

10. Renal insufficiency with creatinine ≥ 3 mg/dl.

11. Woman of childbearing potential who is known to be pregnant or lactating or who hasa positive pregnancy test on admission.

12. Subject participating in a study involving an investigational drug or device thatwould impact this study.

13. Known diagnosis or clinical suspicion of cerebral vasculitis.

14. Patients with a pre-existing neurological or psychiatric disease that would confoundthe neurological or functional evaluations. This excludes patients who are severelydemented, require constant assistance in a nursing home type setting or who live athome but are not fully independent in activities of daily living (toileting,dressing, eating, cooking and preparing meals, etc.).

15. Unlikely to be available for 90 days follow-up (e.g. no fixed home address, visitorfrom overseas).

16. Any other condition that, in the opinion of the investigator will pose a significanthazard to the subject if participating in the trial. Neuroimaging criteria

17. Hypodensity with a posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS) < 6 and Pons-midbrain-index of ≥ 3 on CT angiography source images orMR with diffusion-weighted imaging or non-contrast CT.

18. CT or MR evidence of hemorrhage (the presence of microbleeds on MRI is allowed).

19. Complete cerebellar infarct on CT or MRI with significant mass effect andcompression of the fourth ventricle.

20. Complete bilateral thalamic infarction on CT or MRI.

21. Evidence of vertebral occlusion, high grade stenosis or arterial dissection in theextracranial or intracranial segment that cannot be treated or will prevent accessto the intracranial clot or excessive tortuosity of cervical vessels precludingdevice delivery/deployment.

22. Subjects with occlusions in both anterior and posterior circulation.

23. Evidence of intracranial tumor (except small meningioma).