Immediate Angioplasty for Stroke From Severe Brain Artery Narrowing

Who can take part

• 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

Who cannot take part

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