PCSK9 Inhibitor With Statin Therapy for Asymptomatic Intracranial Atherosclerosis

Inclusion Criteria: 1. Age ≥18 and ≤80, male or female; 2. Asymptomatic intracranial artery stenosis (50%-99%) in the internal carotid artery (C6-7 segments), middle cerebral artery (M1 segment), vertebral artery (V4 segment), or basilar artery, confirmed by angiography (MRA, CTA, or DSA); 3. Atherosclerosis identified as the cause of intracranial artery stenosis by high-resolution magnetic resonance imaging; 4. No previous ischemic cerebrovascular events (including ischemic stroke or transient ischemic attack). 5. Baseline low-density lipoprotein cholesterol ≥ 1.8 mmol/L; 6. Informed consent signed. Exclusion Criteria: 1. Non-atherosclerotic intracranial artery stenosis, including arterial dissection; moya moya disease; systemic vasculitis and primary central nervous system vasculitis; varicella-zoster vasculopathy or other viral vasculopathy; neurosyphilis and other intracranial infections, radiation vasculopathy; fibromuscular dysplasia, sickle cell disease, neurofibromatosis; reversible cerebral vasoconstriction syndrome; postpartum vasculopathy; suspected vasospasm, suspected reperfusion after vessel occlusion. 2. Upstream tandem extracranial vessel stenosis (≥50%) adjacent to the target intracranial stenotic vessel. 3. Previous treatment of target intracranial lesion with endovascular intervention or plan to perform endovascular intervention within 6 months, including intracranial stenting, endovascular angioplasty, and thrombectomy. 4. Any intracranial hemorrhage (parenchymal, subarachnoid, subdural, extradural, intraventricular) within 90 days prior to enrollment. 5. Presence of intracranial tumors. 6. Presence of cerebral aneurysms or arteriovenous malformations with indications for interventional therapy. 7. Major surgery (including open femoral, aortic, or carotid surgery) within previous 30 days or planned in the next 6 months after enrollment. 8. Presence of any of the following unequivocal cardiac sources of embolism: mitral stenosis, mechanical valve, endocarditis, intracardiac clot or vegetation, myocardial infarction within 3 months, dilated cardiomyopathy, chronic or paroxysmal atrial fibrillation. 9. New York Heart Association (NYHA) class III or IV, or known left ventricular ejection fraction \< 30%. 10. Severe liver dysfunction or severe kidney dysfunction: AST and/or ALT \> 3 times the ULN; creatinine clearance \< 0.6 mL/s and/or serum creatinine \> 265 μmol/L (\>3.0 mg/dL); CK \>5 times the ULN at screening. 11. Active bleeding diathesis or coagulopathy (e.g., active peptic ulcer disease, major systemic hemorrhage within 30 days, active bleeding diathesis, platelets count \< 125,000 / uL, hematocrit \< 30%, Hgb \< 10 g/dl, international normalized ratio \>1.5, bleeding time \> 1 minute beyond normal value upper limit). 12. Presence of systemic autoimmune diseases: systemic sclerosis, systemic lupus erythematosus, Sjögren's syndrome, Behçet's disease, mixed connective tissue disease, IgG4-related disease. 13. Dementia or psychiatric problem that hinder their ability to consistently adhere to an outpatient program. Co-morbid conditions that may limit the life expectancy to less than 3 years. 14. Relative/absolute contraindications to magnetic resonance imaging (MRI) (such as presence of internal metallic objects, claustrophobia, contrast agent allergy, severe renal impairment, epilepsy, hypotension, asthma, and other hypersensitivity respiratory diseases). 15. Uncontrolled hypertension during the screening period, defined as seated systolic blood pressure (SBP) \> 180 mmHg or diastolic blood pressure (DBP) \> 110 mmHg. 16. Prior use of PCSK9 inhibitor before this recruitment. 17. Known intolerance or allergy to statin. 18. Pregnancy, lactation, or planning pregnancy. 19. Currently participating in another study.