Pro-urokinase for Extended-Window Posterior Circulation Stroke

Inclusion Criteria: 1. Age ≥ 18 years; 2. AIS with symptom onset 4.5-9 hours before enrollment, including wake-up stroke and unwitnessed stroke (onset time defined as when symptoms were first noticed); 3. Imaging criteria: 1. DWI-FLAIR mismatch: visible lesion on DWI with no marked visible lesion on FLAIR; 2. DWI infarct core not exceeding one-third of the middle cerebral artery territory, one-half of the anterior cerebral artery territory, or one-half of the posterior cerebral artery territory; 4. NIHSS score 4-25; 5. First-ever stroke or previous stroke without significant disability (pre-stroke mRS ≤ 1); 6. Signed informed consent from the patient or legally authorized representative. Exclusion Criteria: 1. Planned endovascular treatment; 2. Contradictory to MRI examination; 3. MRI image not qualified for evaluation; 4. Serious neurological deficits before onset (mRS≥2); 5. Obvious head injuries or strokes within 3 months; 6. Subarachnoid or intracranial hemorrhage; 7. History of intracranial hemorrhage; 8. Intracranial tumor, arteriovenous malformation or aneurysm; 9. Intracranial or spinal cord surgery within 3 months; 10. Active internal hemorrhage; 11. platelet count of \<100000/mm3; 12. Aortic arch dissection; 13. Heparin therapy within 24 hours; 14. Oral warfarin is being taken and INR\>1.6 or APTT abnormal; 15. Oral anticoagulation therapy; 16. Systolic pressure≥185 mmHg or diastolic pressure≥110 mmHg; 17. Blood glucose \< 50 mg/dl (2.7mmol/L); 18. Pregnancy; 19. Neurological deficit after epileptic seizures; 20. Major surgery within 1 month; 21. Gastrointestinal or urinary tract hemorrhage within the previous 30 days; 22. Myocardial infarction within 3 months; 23. Allergy to study drugs; 24. Unlikely to adhere to the trial protocol or follow-up; 25. Any condition that, in the judgment of the investigator could impose hazards to the patient if study therapy is initiated or affect the participation of the patient in the study; 26. Participation in other interventional clinical trials within the previous 3 months.