Subclavian loop catheterization technique (SLOT): novel transradial salvage technique for challenging vertebral artery ostial stenosis

OBJECTIVE: To evaluate the efficacy and safety of the subclavian loop catheter technique for endovascular stenting of vertebral artery ostial stenosis (VAOS). METHODS: We retrospectively reviewed all patients who underwent vertebral artery stenting between January 2022 and April 2025. The analysis included only those in whom standard transradial access (TRA) failed and the subclavian artery loop technique was used. Outcomes assessed included vascular access and surgical complications, postoperative modified Rankin Scale (mRS) scores, and in-stent restenosis on follow-up. RESULTS: Of 134 vertebral artery stenting procedures, 12 cases in which standard TRA failed were successfully completed using the subclavian loop catheter technique. Patients were aged 18-80 years, and VAOS was more frequent on the right side (n=11/12). Mean preoperative stenosis was 79%, reduced to 7.5% after stenting. No major periprocedural complications occurred. Median time from catheter loop formation to stent deployment was 33 min. Median follow-up was 3 months, during which 67% of patients were assessed and no in-stent restenosis was detected. CONCLUSIONS: The subclavian loop catheter technique via TRA was a safe, effective, and feasible option for VAOS stenting when conventional radial or transfemoral access was limited by vascular anatomy. The technique provided stable access, enabled precise stent deployment, and demonstrated a favorable safety profile in this series.