Immediate Angioplasty For Acute Ischemic Stroke With Severe Intracranial Atherosclerotic Stenosis

Prior treatment

• Concomitant intracranial tumor (except for meningioma \<10mm) or arteriovenous malformation.

Other illness

• Hemorrhagic stroke within the past 90 days.
• Cerebrovascular conditions such as vasculitis, moya-moya disease, arterial inflammatory stenosis, vasospasm, traumatic dissection, etc..
• Known cardiac thrombus source (e.g., atrial fibrillation, patent foramen ovale, infective endocarditis).
• Intracranial hemorrhage confirmed by CT or MRI.
• Severe allergy to contrast (non-mild rash allergy) or absolute contraindication to iodine contrast.
• Any active bleeding or recent bleeding in the last 1 month.
• Anticipated life expectancy \<3 months (e.g., malignancy, severe cardiopulmonary disease, etc.).
• Any condition that, in the judgment of the investigator, makes the patient unsuitable for this study or where this study may impose a significant risk to the patient (e.g., inability to understand and/or comply with study procedures and/or follow-up due to psychiatric disorders, cognitive or emotional impairment).

Lab values

• INR \>1.7 when using warfarin; coagulation dysfunction or uncorrectable bleeding factors.
• Platelet count \<50×10\^9/L.
• Known severe renal insufficiency with glomerular filtration rate \<30 ml/min or blood creatinine \>220 μmol/L (2.5 mg/dl).

Other

• Normal diameter of the culprit vessel \<2.0 mm.
• Isolated perforator artery infarction (except for combined cortical hypoperfusion).
• Severe calcification at the stenosis site, where expected residual stenosis ≤50% cannot be achieved with procedure.
• Women who are pregnant or breastfeeding.
• Participation in other intervention clinical trials.
• Aortic dissection.
• Severe vascular tortuosity, difficult access for intervention, or inability to complete endovascular treatment.
• SBP\>185 mmHg or DBP\>110 mmHg refractory to treatment.

• Aged 18 years or older.
• Diagnosed with AIS and baseline NIHSS ≥6.
• Pre-stroke mRS ≤2.
• Time from symptom onset to randomization ≤ 24 hours; the onset time refers to "Last Known Well" (LKW).
• Non-contrast CT ASPECTS score ≥6.
• CTA confirmed severe ICAS (70-99%) of the intracranial segment of the internal carotid artery, or M1 or M2 segment of the middle cerebral artery, and is presumed to be responsible for the stroke.
• Informed consent signed by the patient or authorized representative.