Balloon angiopLasty for Intracranial Atherosclerotic Minor Stroke/TIA

1. age range of 30-80 years;
2. symptomatic ICAS (C4-C7 segments of ICA, M1 segment of the MCA, V4 segment of the VA, and BA) with 70%-99% stenosis confirmed by DSA;
3. minor stroke (NIHSS score ≤5) within 1 week of onset or from symptom exacerbation (NIHSS score increased by ≥2 points) or intermediate- to high-risk TIA, defined as ABCD2 score ≥4 within 1 week of the last symptom episode;
4. diameter of the culprit artery ranging from 2.0 to 4.5mm, and the length of the stenosis≤14mm;
5. mRS ≤ 2 before endovascular treatment；
6. no large ischemic region found on CT or MRI (ASPECTS≥ 6 or pc-ASPECTS ≥8)；
7. written informed consent obtained from the patient or legally responsible person.

Exclusion Criteria:

1. allergy to contrast media;
2. non-atherosclerotic disease-related stenosis, such as arterial dissection, Moya-Moya disease, and arteritis;
3. penetrating branch lesion ipsilateral to the target lesion (infarction caused by penetrating branch occlusion is defined as stenosis of the MCA or BA, but only with simple basal ganglia or brainstem/thalamic infarction);
4. presence of severe stenosis of the extracranial segment on the side of the target lesion;
5. previous endovascular treatment of the ipsilateral vessel;
6. presence of intracranial aneurysms, tumors, and vascular malformations;
7. any form of ipsilateral intracranial hemorrhage within 3 months and contralateral intracranial hemorrhage within 2 weeks;
8. presence of atrial fibrillation, severe heart dysfunction, liver or kidney dysfunction; patients with tumors and serious diseases whose expected survival time is ≤ 1 year;
9. hemoglobin ≤ 100g/L, platelet count ≤ 100×10\^9/L, INR> 1.5 (irreversible), coagulopathy or irremediable bleeding factors;
10. uncontrollable hypertension: systolic blood pressure >185 mmHg and/or diastolic blood pressure >110 mmHg;
11. poor glycemic control (random blood glucose > 22.2 mmol/L);
12. history of major surgery within 30 days prior to enrollment or surgery plan within 90 days after enrollment;
13. pregnancy or lactation;
14. other conditions that the researchers think make the patient unsuitable for the study.