Feasibility and predictors of failure in a distal transradial-first access strategy for endovascular treatment of intracranial aneurysms: A single-center study of 208 cases.

PURPOSE: To assess the feasibility, procedural success, predictors of failure, and complications associated with the distal transradial approach (dTRA) as first-line endovascular treatment for intracranial aneurysms. METHODS: We retrospectively reviewed 208 patients (211 aneurysms) treated between April 2024 and April 2025 in whom dTRA was the default access. Success rates, factors associated with failure, and access-related complications were analyzed. RESULTS: Transradial approach (TRA) puncture success was achieved in 97.1% (202/208) of cases, with an overall success rate of 92.8% (193/208). For dTRA, the puncture success rate was 83.2% (159/191), with treatment success of 95.6% (152/159) after puncture success, comparable to conventional TRA. After successful puncture, procedures through the right internal carotid artery (ICA), left ICA with bovine aortic arch, and bilateral vertebral arteries were all successful, whereas those via the left ICA with a non-bovine aortic arch showed a lower success rate (52/61, 85.2%). In this subgroup, TRA failure was associated with shorter stature (160 cm vs. 151 cm, p=0.039), diabetes mellitus (11.5% vs. 44.4%, p=0.032), smaller brachiocephalic artery-left common carotid artery (BCA-LCCA) angle (19.9° vs. 5.5°, p=0.009), and type III aortic arch (42.3% vs. 88.9%, p=0.013). The optimal BCA-LCCA angle cut-off was 9.4° (area under the curve, 0.78). Access-related complications occurred in 3.4% (7/208) of patients. No symptomatic radial artery occlusion or dissection was observed. CONCLUSION: TRA with dTRA as a first-line access is feasible and effective. Left ICA access with a non-bovine aortic arch remains technically challenging, particularly in patients with unfavorable factors.