Clinical Study of PCSK9 Inhibitors for Preventing Early Neurological Deterioration in Branch Atheromatous Disease

INTERVENTION: Experimental group:Evolocumab 140 mg subcutaneously combined with Rosuvastatin 20 mg orally;Control group:Rosuvastatin 20 mg orally; CONDITION: Acute Ischemic Stroke PRIMARY OUTCOME: Incidence of Early Neurological Deterioration (END) and incidence of Severe Early Neurological Deterioration (SEND);Lipid attainment rate (Day 7, Day 30); SECONDARY OUTCOME: Incidence and severity of Adverse Events (AE), Important Adverse Events, and Serious Adverse Events (SAE);Proportion of patients with favorable neurological prognosis at day 90;Recurrence rate of symptomatic cardiovascular and cerebrovascular events within 90 days;Incidence of Ultra‐early Neurological Deterioration (UEND); INCLUSION CRITERIA: 1.Aged between 18 and 80 years(inclusive); 2.Patients diagnosed with acute ischemic stroke within 24 hours after symptom onset; 3.High‐resolution magnetic resonance imaging (HR‐MRI) confirms infarction in the lenticulostriate artery territory (single deep subcortical infarction; axial view: involving =3 slices with slice thickness of 5–7 mm; coronal view: fan‐shaped/comma‐shaped lesions extending from the basal ganglia upward to the corona radiata; locations: putamen, caudate nucleus, anterior/superior genu of internal capsule, corona radiata; size: lesion diameter usually =15 mm) or infarction in the paramedian pontine artery territory (location: ventral pons, paramedian, unilateral, reaching the pontine surface); 4.First‐ever stroke patients, or recurrent stroke patients without sequelae such as limb paralysis that interfere with the current NIHSS score; modified Rankin Scale (mRS) score =1 prior to this stroke; 5.Written informed consent obtained.