Intravenous Thrombolysis Combined With Tirofiban in Acute Ischemic Stroke

Inclusion Criteria: 1. Age ≥18 years. 2. Pre-stroke modified Rankin Scale (mRS) score of 0-1. 3. Acute ischemic stroke symptoms within 4.5 hours of last known well time. 4. Baseline National Institutes of Health Stroke Scale (NIHSS) score ≥4. 5. Poor neurological improvement 1 hour after intravenous thrombolysis, defined as NIHSS decrease \<2 points, or neurological worsening within 1 hour, defined as NIHSS increase ≥1 point. 6. Not planned for or not eligible for endovascular treatment. 7. Subject or legally authorized representative can provide written informed consent. Exclusion Criteria: 1. Evidence of intracranial hemorrhage on imaging before randomization. 2. Non-ischemic intracranial pathologies, such as vascular malformation, aneurysm, tumor, abscess, or demyelinating disease. 3. Large or medium vessel stenosis requiring thrombectomy or intra-arterial thrombolysis. 4. Contraindications to tirofiban, including but not limited to:Known hypersensitivity to tirofiban; Severe hepatic dysfunction (ALT \>2× ULN or AST \>2× ULN); Severe renal dysfunction (serum creatinine \>1.5× ULN); Advanced heart failure (NYHA class III-IV); Coagulation disorders or history of systemic bleeding; History of thrombocytopenia or neutropenia; Prior drug-induced hematologic disease or liver dysfunction; Leukopenia (\<2×10\^9/L) or platelet count \<100×10\^9/L. 5. Use of tirofiban or other GP IIb/IIIa inhibitors before randomization, or planned use of such agents after randomization. 6. Definite cardioembolic source, including but not limited to: chronic or paroxysmal atrial fibrillation, sick sinus syndrome, mitral stenosis, mechanical prosthetic heart valves, infective endocarditis, history of intracardiac thrombus, myocardial infarction within 3 months, dilated cardiomyopathy, spontaneous left atrial echo contrast, or left ventricular ejection fraction \<30%. 7. Pregnancy or lactation. 8. Expected survival \<6 months. 9. Pre-existing neurological or psychiatric disorders that may interfere with outcome assessment. 10. Unlikely to complete 90-day follow-up.