Sivelestat Sodium as an Adjunct to Endovascular Thrombectomy for Acute Anterior Circulation Large-Vessel Occlusion

Inclusion Criteria: * 1.Symptoms and signs consistent with focal ischemia in the anterior circulation; * 2.Large vessel occlusion of the anterior circulation (internal carotid artery, M1/M2 segment of the middle cerebral artery) confirmed by CTA/MRA/DSA; * 3.Undergoing mechanical thrombectomy; * 4.Age between 18-80 years, both male and female; * 5.Pre-stroke modified Rankin Scale (mRS) score ≤1; * 6.Time from symptom onset to thrombectomy ≤24 hours, including wake-up stroke or unwitnessed stroke; symptom onset is defined as the "last known well" (LKW); * 7.National Institutes of Health Stroke Scale (NIHSS) score ≥6 at admission; * 8.ASPECTS ≥3 for anterior circulation occlusion; * 9.Written informed consent provided by the patient or their legal representative. Exclusion Criteria: * 1．Simultaneous acute occlusion of both the anterior and posterior circulation, or bilateral acute large-vessel occlusion in the anterior circulation; * 2．Failure to obtain a baseline NIHSS score before sedation or intubation by a neurologist or emergency physician; * 3．Seizure at stroke onset that precludes assessment of the baseline NIHSS score; * 4．Bilateral dilated pupils; * 5．Known allergy to sivelestat sodium or any of its excipients; * 6．Severe allergy or absolute contraindication to iodinated contrast agents; * 7．Systolic blood pressure \>185 mmHg or diastolic blood pressure \>110 mmHg that cannot be controlled with antihypertensive therapy; * 8．Blood glucose \<50 mg/dL (2.8 mmol/L) or \>400 mg/dL (22.2 mmol/L); * 9．Platelet count \<50 \* 10⁹/L; * 10．Hereditary or acquired bleeding tendency, coagulation factor deficiency, current oral anticoagulant use with INR \>1.7, or oral anticoagulant treatment within the previous 48 hours; * 11．Severe renal failure, defined as serum creatinine \>3.0 mg/dL (265.2 μmol/L), glomerular filtration rate (GFR) \<30 mL/min, or requirement for hemodialysis or peritoneal dialysis; * 12．Inability to complete the 90-day follow-up (e.g., no fixed residence or overseas patients); * 13．Suspected vasculitis or septic embolism; * 14．Suspected aortic dissection; * 15．Evidence of intracranial tumor (except small meningioma), acute intracranial hemorrhage, tumor, or arteriovenous malformation; * 16．Significant mass effect with midline shift; * 17．Evidence of internal carotid artery dissection causing flow limitation; * 18．Neurological disease or psychiatric disorder that may interfere with evaluation of the patient's condition; * 19．Pregnant or breastfeeding women; * 20．Confirmed rheumatic or autoimmune disease with long-term use of immunosuppressants or corticosteroids; * 21．Current treatment with chemotherapy or other immunomodulatory agents (e.g., recombinant human granulocyte colony-stimulating factor, Xuebijing, or ulinastatin); * 22．Participation in another clinical trial that may interfere with the results of this study; * 23．Any other condition that, in the opinion of the investigator, would make the patient unsuitable for participation or may pose a significant risk to the patient.