Identifying Beneficiaries of Bailout Intracranial Angioplasty or Stenting Following Thrombectomy: A Secondary Analysis of the ANGEL-REBOOT Trial

BACKGROUND AND PURPOSE: The Randomized Trial of Bailout Intracranial Angioplasty or Stenting Following Thrombectomy for Acute Large Vessel Occlusion (ANGEL-REBOOT) demonstrated no overall benefit from bailout angioplasty or stenting (BAOS) following thrombectomy for acute large-vessel occlusion. Nonetheless, the heterogeneous patient population suggests potential subgroup benefits. We aimed to identify the specific subgroups that may benefit from BAOS after thrombectomy for acute large-vessel occlusion. MATERIALS AND METHODS: This is a secondary analysis of the ANGEL-REBOOT trial, a multicenter randomized controlled trial conducted in China from December 2021 to March 2023, which included participants with large-vessel occlusion within 24 hours of symptom onset who had unsuccessful recanalization or >70% residual stenosis after thrombectomy. Participants were stratified into three subgroups: (1) refractory occlusion, (2) intracranial atherosclerotic-related large-vessel occlusion with unsuccessful recanalization (ICAS-LVO-UR) after thrombectomy, and (3) ICAS-LVO with successful recanalization (ICAS-LVO-SR) after thrombectomy. Efficacy and safety outcomes were assessed in the short term (90 days) and long term (1 year). RESULTS: A total of 347 participants were included in this secondary analysis and divided into three subgroups: refractory occlusion (n=20), ICAS-LVO-UR (n=95), and ICAS-LVO-SR (n=232). For short-term efficacy, the refractory occlusion subgroup showed worse 90-day modified Rankin Scale (mRS) outcomes with BAOS versus standard therapy (common odds ratio OR, 0.14 95% CI, 0.02–0.81); the ICAS-LVO-SR and ICAS-LVO-UR subgroups showed favorable and unfavorable trends, respectively. In the long-term, BAOS significantly improved the 1-year outcomes in the ICAS-LVO-SR subgroup: better mRS distribution (generalized OR, 1.72 95% CI, 1.07–2.77), higher functional independence (OR, 2.80 95% CI, 1.59–4.92), and reduced target-vessel stroke recurrence (hazard ratios HR, 0.25 95% CI, 0.08–0.75). No significant long-term findings were observed in the other two subgroups. Safety outcomes were comparable between the BAOS and standard therapy groups across all subgroups. CONCLUSIONS: In this secondary analysis of the ANGEL-REBOOT trial, BAOS was associated with improved 1-year outcomes in patients with successful recanalization (eTICI ≥2b) but residual severe stenosis (≥70%) after thrombectomy. Given the inherent limitations of this analysis, these findings should be interpreted as hypothesis-generating and warrant confirmation in future large-scale prospective trials.