HR-MRI-Directed Tirofiban Therapy for Late-Window Acute Ischemic Stroke (TIAN)

Inclusion Criteria: 1. Age ≥ 18 years old; 2. Acute ischemic stroke (AIS) in the anterior intracranial circulation (internal carotid artery system) confirmed by clinical symptoms and imaging examinations; 3. Time from symptom onset or last known normal state to randomization: \> 24 hours and ≤ 7 days; 4. Stroke subtype confirmed as intracranial large artery atherosclerosis (ICAS) by high-resolution vessel wall imaging (HR-VWI) according to the TOAST classification, with cardiogenic embolism and other etiologies excluded; 5. Baseline National Institutes of Health Stroke Scale (NIHSS) score of 4-20 at the time of randomization; 6. Signed informed consent form obtained from the patient or their legal representative. Exclusion Criteria: 1. Planned to receive reperfusion therapy (endovascular therapy or intravenous thrombolysis)； 2. Intracranial hemorrhage confirmed by computed tomography (CT)； 3. Definite or suspected cardiogenic embolism； 4. History of atrial fibrillation or current electrocardiogram indicating atrial fibrillation； 5. Acute ischemic stroke caused by other etiologies, such as Moyamoya disease, arterial dissection, arteritis, etc； 6. Imaging examinations indicating that the area of the current cerebral infarction exceeds 1/2 of the area of a single cerebral lobe; 7. Known contraindications to antiplatelet therapy, including hematochezia, gastrointestinal bleeding, or any other hemorrhagic disorders; 8. History of hypersensitivity to aspirin; 9. Definite indication for anticoagulant therapy expected during the study period (e.g., atrial fibrillation, mechanical heart valve, deep vein thrombosis, pulmonary embolism, antiphospholipid antibody syndrome, hypercoagulable state, etc.); 10. Complicated with malignant tumors, chronic hemodialysis, severe renal insufficiency (glomerular filtration rate \[GFR\] \< 30 ml/min or serum creatinine \[Cr\] \> 220 μmol/L (2.5 mg/dl)), or severe hepatic insufficiency (serum alanine aminotransferase \[ALT\] \> 2 times the upper limit of normal \[ULN\], or serum aspartate aminotransferase \[AST\] \> 2 times the ULN); 11. Severe heart failure (New York Heart Association \[NYHA\] Functional Classification Class III or IV); 12. Complicated with severe non-cardiovascular comorbidities, with an estimated survival time \< 6 months; 13. Concurrent new cerebral infarction in both anterior and posterior circulations; 14. Inability to complete the follow-up procedures; 15. Presence of other known neurological disorders that may complicate the follow-up; 16. Concurrent participation in other therapeutic clinical trials with incomplete treatment and follow-up; 17. Other conditions that the investigators consider inappropriate for enrollment in this study.