Learning curve of distal radial access for coronary procedures: prospective, multicenter, observational study (IDEAL-BOX)

While distal radial access (DRA) is increasingly used for coronary procedures, prospective data on its learning curve remain limited. We evaluated procedural outcomes in experienced and inexperienced operators. This prospective, multicenter, observational study enrolled 800 patients in whom DRA was attempted by four operators (two inexperienced and two experienced), each performing 200 cases. The primary endpoint was the trend in rates of successful coronary procedures without access-site crossover across four sequential 50-case blocks. Inexperienced operators showed a significant improvement across the case quartiles (83.0% in Q1 to 99.0% in Q4, P for trend < 0.001), whereas experienced operators maintained consistently high success rates (95.0% in Q1 to 93.0% in Q4, P for trend > 0.999). Although inexperienced operators showed a significantly lower success rate during Q1 compared to experienced operators (83.0% vs. 95.0%, P = 0.010), this inter-group difference was not significant in subsequent quartiles (Q2–Q4). No significant difference was observed in the overall procedural success rate without access-site crossover (observed, 92.5% [370/400] vs. 94.5% [378/400]; model-estimated, 94.9% vs. 95.5%, P = 0.714). The procedural success rate of inexperienced operators was lowest in the first 50 cases and did not differ significantly from that of experienced operators after 50 cases.