Feasibility and Safety of High RIST Catheter Placement via Transradial Approach for Unruptured Anterior Circulation...

The transradial approach using dedicated guiding catheters, such as the RIST guiding catheter, has gained popularity in neuroendovascular treatment. However, concerns remain regarding system instability. We evaluated the feasibility and safety of transradial approach with advancement of the RIST to a higher and more stable position (petrous to cavernous segment of the internal carotid artery). We conducted a single-center, retrospective, era-based cohort study comparing a transfemoral approach-first era (2022-2023) with a transradial approach with high RIST placement-first era (2024-2025). Consecutive adult patients who underwent endovascular treatment for unruptured intracranial aneurysms were included. After the exclusion of posterior circulation and ruptured aneurysms, 171 procedures (96 transfemoral approach and 75 transradial approach) were analyzed. The primary outcome was procedural success. Safety outcomes included neurological complications, access-site complications, and 30-day mortality. The primary analysis was era-based; sensitivity analyses were performed per protocol, and subgroup analyses focused on lesion laterality. In the transradial approach-first era, the procedural success rate was 99% (odds ratio 1.57, 95% confidence interval 0.14-17.70, p > 0.99), neurological complications occurred in 3%, access-site complications in 3%, and 30-day mortality in 0%, comparable to those in the transfemoral approach-first era. Sensitivity analyses restricted to cases with high RIST placement yielded similar results. The subgroup analysis did not reveal any interaction between outcomes and lesion laterality; The P-values for interaction were 0.294 for procedural success, 0.079 for periprocedural neurological complications, and 0.176 for access-site complications. Transradial approach using a high RIST placement appears feasible and safe, achieving high success and low complication rates.