PCSK9 Inhibitor for Intracranial Atherosclerosis Related Acute Ischemic Stroke

Inclusion Criteria: * Age \>=30 and \<=80;2.Acute ischemic stroke within 72 hours of onset (as determined by CT/MRI in conjunction with neurological deficit symptoms) * Acute ischemic stroke within 72 hours of onset (diagnosed by CT/MRI in conjunction with neurological deficit symptoms) * NIHSS score of 4-25 at admission * Imaging studies (CTA/DSA/MRA) support intracranial atherosclerosis as the cause of stroke, meeting one of the following criteria: i. The culprit vessel exhibits intracranial atherosclerotic stenosis (ICAS) with a narrowing degree of 50-99%; ii. The culprit vessel exhibits intracranial atherosclerotic occlusion (ICAS-LVO), with successful recanalization achieved via mechanical thrombectomy (immediate expanded thrombolysis in cerebral infarction \[eTICI\] grade 2b50-3) * Informed consent signed Exclusion Criteria: * Non-atherosclerotic intracranial arterial stenosis (such as arterial dissection, Moyamoya disease, systemic vasculitis, etc.) * Any identifiable source of cardiogenic embolism (such as atrial fibrillation, mechanical valves, left ventricular thrombus, patent foramen ovale, etc.) * Imaging findings and clinical presentation suggest that the primary pathophysiology of this event is more consistent with cerebral small vessel disease (e.g., perforator artery occlusion/lacunar infarction) * Pre-existing disability prior to this ischemic event (modified Rankin Scale ≥ 2 points) * CT or MRI findings suggest extensive cerebral infarction (e.g., ASPECTS…