Early Administration of PCSK9 Inhibitors After Thrombectomy for Atherosclerotic Acute Ischemic Stroke: A Randomized Controlled Trial

Inclusion Criteria: 1. Age 18-85 years old, gender not limited, gender ratio not limited. 2. The clinical diagnosis was acute ischemic stroke with occlusion of the anterior circulation large vessels. CTA/DSA confirmed that the responsible vessel for this stroke occlusion was located in the intracranial segment of the internal carotid artery and the M1 segment of the middle cerebral artery. 3. The time from onset to puncture is within 24 hours, and the patient receives mechanical thrombectomy (MT) (including direct thrombectomy and intravenous thrombolysis bridging thrombectomy), with postoperative vascular recanalization reaching mTICI grade 2b or 3. The surgical indications and time window follow the current guidelines and imaging criteria of key randomized controlled trials (RCTs). The definitions are as follows: Early window (0-6 h): Meeting the usual EVT indications (anterior circulation LVO, baseline NIHSS ≥ 6, ASPECTS ≥ 6, or center-defined criteria), the interventional team decides to perform MT; Late window (6-24 h): Meeting one of the imaging selection criteria of DAWN or DEFUSE-3 (based on CTP-RAPID or MRI-DWI/perfusion): ·DAWN (6-24 h) (any one): Age ≥ 80 years: NIHSS ≥ 10 and core infarct volume \< 21 mL; Age \< 80 years: NIHSS ≥ 10 and core \< 31 mL; Age \< 80 years: NIHSS ≥ 20 and core 31-51 mL. • DEFUSE-3 (6-16 h) (all conditions must be met): Core \<70 mL, mismatch ratio (penumbra/core) ≥1.8, mismatch volume ≥15 mL, and Tmax \>6 s volume \>15 mL. 4. The etiological classification is intracranial arteriosclerosis-LAA (ICAD-LAA). The definition is as follows: imaging evidence supports the presence of atherosclerotic stenosis/plaque in the responsible vessel (such as severe stenosis/occlusion of the proximal internal carotid artery or middle cerebral artery) and the patient has corresponding underlying atherosclerosis (such as other intracranial/extracranial artery stenosis, hypertension, diabetes, etc.). 5. Baseline National Institutes of Health Stroke Scale (NIHSS) score ≥ 6 points. 6. Before the onset of the disease, the patient had good daily living abilities and an mRS score ≤ 2 (no severe disability). 7. Able to complete the injection of research drugs as required. 8. The patient or his or her legal representative shall sign a written informed consent form, understand the research content and agree to cooperate with the follow-up. Exclusion Criteria: 1. Non-atherosclerotic lesions (such as arterial dissection, Moyamoya disease, vasculitis, embolism of unknown origin, etc.). 2. Patients who present with significant intracranial hemorrhage or excessively large cerebral infarction volume upon admission, making them unsuitable for continued participation in the study. 3. The cause of stroke is cardioembolism (such as a history of heart disease such as atrial fibrillation or valvular heart disease). 4. Individuals with a clear history of allergy to evolocumab or its excipients. 5. Patients with severe liver and kidney dysfunction: baseline alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 3 times the upper limit of normal, or significantly reduced creatinine clearance (eGFR \< 30 mL/min/1.73m²). 6. Patients with active severe infection, immune system disease or other serious comorbidities that may significantly affect prognosis (such as active tumors, terminal diseases, etc.). 7. Patients who have been treated with PCSK9 inhibitors within the past 4 weeks (to avoid affecting the study due to changes in tolerance or mechanism of action). 8. Pregnant or lactating women. 9. Expected survival \<90 days or accompanied by other serious diseases. 10. Currently participating in other interventional clinical studies.