A Randomized Clinical Trial on Urgent Angioplasty for IntraCranial Atherosclerotic Stenosis-related Large-Vessel Occlusion After Mechanical Thrombectomy

Inclusion Criteria: Clinical inclusion criteria: 1. Age ≥ 18 years 2. National Institutes of Health Stroke Scale (NIHSS) score ≥6 before randomization 3. To receive mechanical thrombectomy \<24 hours after AIS onset according to local guidelines 4. Signed informed consent form obtained from the subject (or approved surrogate) Imaging inclusion criteria: 1. For subjects with anterior circulation stroke, ASPECTS ≥6 based on CT or DWI 2. For subjects with posterior circulation stroke, posterior circulation ASPECTS (pc-ASPECTS)≥6 and pons-midbrains index (PMI) \< 3 based on CT or DWI Angiography inclusion criteria: 1. The responsible occluded vessel is immediately recanalized (eTICI≥2b) after mechanical thrombectomy, ICAS is highly suspected and the focal residual stenosis of the main trunk is≥70%, and the responsible occluded vessels include the intracranial segment of the internal carotid artery, the M1 segment of the middle cerebral artery, the V4 segment of the vertebral artery, and the basilar artery 2. According to the judgment of the neurointerventional physician, the responsible artery is suitable for stenting angioplasty Exclusion Criteria: 1. Pre-stroke mRS \>2 2. Intracranial hemorrhage confirmed by CT before mechanical thrombectomy and enrolment 3. Suspected Intracranial hemorrhage after successful recanalization confirmed by 3D-CT 4. Tandem lesions: stenosis (or occlusion) of the extracranial segment of the internal carotid artery or vertebral artery combined with occlusion of large intracranial vessels, stenosis of intracranial arteries combined with occlusion of vessels distal to the stenosis 5. More than two severe stenosis of the responsible occluded vessel (internal carotid artery, middle cerebral artery, vertebral artery, and basilar artery) 6. Potential cardiac sources of emboli such as atrial fibrillation, left ventricular thrombus, heart valve replacement, atrial septal defect, ventricular septal defect, atrial myxoma, etc. 7. Current use of oral anticoagulants 8. Major surgery or serious trauma in the previous 2 weeks 9. Contraindication for mechanical thrombectomy or stenting angioplasty 10. Contraindication for antiplatelet treatment or allergy to contrast agent 11. History of gastrointestinal or urinary bleeding in the previous 3 weeks 12. Life expectancy less than 1 years 13. Current pregnant or breastfeeding status 14. Currently participating in another clinical trial that may affect the outcome assessment of this trial 15. Any other condition that, in the investigator's judgement, deems the individual unsuitable for enrolment.