Efficacy and Safety of Bailout Intracranial Angioplasty or Stenting After Thrombectomy for Acute Intracranial Atherosclerotic Large Vessel Occlusion: A Clinical Trial Combining a Randomized Controlled Trial and a Concurrent Prospective Observational Cohort

This is a clinical trial with a composite design, consisting of: (1) a multicenter, prospective, open-label, blinded-endpoint randomized controlled trial (RCT) for patients with successful recanalization but residual severe stenosis (>70%) after thrombectomy, and (2) a concurrent prospective observational cohort for patients with failed recanalization. Patients with acute ischemic stroke due to intracranial atherosclerotic stenosis-related large vessel occlusion (ICAS-LVO) within 24 hours of symptom onset who undergo up to two thrombectomy passes are assessed. Those achieving successful recanalization (expanded Thrombolysis in Cerebral Infarction [eTICI] grade ≥2b) but with residual stenosis ≥70% are enrolled in the RCT and randomly assigned in a 1:1 ratio to receive either bailout angioplasty or stenting (BAOS) (intervention group) or standard therapy (control group). Randomization is performed using a centralized interactive web response system with a minimization method, stratified by baseline National Institutes of Health Stroke Scale score (6-15 vs. ≥16), time from symptom onset to puncture (≤6 hours vs. 6-24 hours), and occlusion site (anterior circulation vs. posterior circulation). For patients who fail to achieve successful recanalization (eTICI 0-2a) after at least two thrombectomy passes, they are enrolled in the concurrent prospective observational cohort without randomization, and subsequent treatment (including continued thrombectomy, BAOS, or termination of the procedure) is at the discretion of the treating physician. The primary endpoint is the modified Rankin Scale (mRS) score at 90 days (±7 days) after randomization or enrollment. Key secondary efficacy endpoints include the proportion of patients with mRS scores of 0-1, 0-2, and 0-3 at 90 days; stroke recurrence in the target vessel territory within 90 days and 1 year; NIHSS score at 24 hours; and quality of life measures at 90 days and 1 year. Safety endpoints include symptomatic intracranial hemorrhage within 24 hours (defined by the Heidelberg Bleeding Classification), any intracranial hemorrhage within 24 hours, mortality at 7 days, 90 days, and 1 year, and procedure-related complications (e.g., arterial perforation, dissection, or distal embolization). Follow-up assessments are performed at 24 hours, 7 days or discharge (whichever occurs first), 90 days, and every 3 months thereafter until 1 year after randomization or enrollment.