Endovascular Thrombectomy Alone Versus Intravenous Thrombolysis Plus Thrombectomy on Acute Basilar Artery Occlusion

Inclusion Criteria: 1. Patients presenting with posterior circulation ischemic stroke symptoms due to basilar artery occlusion or vertebral artery occlusions that prevent antegrade flow into the basilar artery; 2. Time from stroke onset to randomization within 4.5 hours of estimated time of basilar artery occlusion; 3. Patient's age ≥ 18 years; 4. Presence of basilar artery or vertebral artery occlusion, confirmed by CT Angiography (CTA), MR Angiography (MRA) or Digital Subtraction Angiography (DSA). In case of vertebral artery occlusion, the occlusion must completely prevent antegrade flow into the basilar artery; 5. Patients presenting with acute ischemic stroke eligible to receive both endovascular thrombectomy and intravenous thrombolysis using standard criteria; 6. Baseline National Institutes of Health Stroke Scale (NIHSS) score ≥ 10; 7. The patient or patient's legal representative signs the informed consent form. Exclusion Criteria: 1. CT or MR evidence of intracerebral hemorrhage (the presence of \< 10 microbleeds is allowed); 2. Pre-stroke modified Rankin scale (mRS) score ≥ 2; 3. Posterior circulation Acute Stroke Prognosis Early CT Score (PC-ASPECTS) on CT/ CTA-Source Images\<6; PC-ASPECTS on magnetic resonance imaging-diffusion weighted imaging (MRI-DWI) \<5; 4. Pregnant or lactating women; 5. Allergy to contrast agent or nitinol alloy; 6. Life expectancy\<1 year; 7. CTA/MRA/DSA show vascular tortuosity, anatomical variation or artery dissection, which would make it difficult to perform endovascular treatment; 8. Participating in other clinical trials; 9. Systolic blood pressure \>185 mmHg or diastolic blood pressure \>110 mmHg, which can not be controlled by antihypertensive drugs; 10. Genetic or acquired hemorrhagic diathesis, lack of anticoagulant factor; oral anticoagulant with international normalized ratio (INR) \> 1.7; or novel oral anticoagulant within prior 48 hours; 11. Blood glucose \<50 mg/dl (2.8 mmol/L) or \>400 mg/dl (22.2 mmol/L), platelet\< 100\*109/L; 12. Renal insufficiency defined as serum creatinine \>2.0 mg/dl (or 176.8 μ mol/l), glomerular filtration rate \<30 mL/min, need for hemodialysis or peritoneal dialysis; 13. Patients who cannot complete 90-day follow-up (such as patients without fixed residence, overseas patients, etc); 14. The patient has acute ischemic cerebral infarction within 3 months from randomization; 15. The patient had a history of or clinical suspicion for cerebral vasculitis or infectious endocarditis; 16. The patient has nervous system disease or mental disorder before stroke onset, which may affect the assessment of their condition; 17. CT or MR examination showed large cerebellar infarction with obvious space occupying effect and compression of the fourth ventricle; 18. Patients with extensive bilateral thalamic or extensive bilateral brainstem infarction on CT or MR examination; 19. CTA/MRA/DSA show both anterior and posterior circulation large vessel occlusion; 20. Patients with intracranial tumors (except small meningiomas); 21. Patients who received intravenous thrombolytics treatment before the randomization.