Crossover patterns and temporal trends in distal vs conventional radial access: Meta-analysis of randomized trials

Background: Distal radial access (DRA) has emerged as an alternative to conventional transradial access (TRA) for percutaneous coronary procedures, but concerns remain regarding higher crossover rates. The evolution and characteristics of these crossovers remain insufficiently characterized. Objectives: To evaluate crossover patterns and temporal trends of DRA compared with TRA in randomized controlled trials (RCTs). Methods: We conducted a systematic review and meta-analysis of RCTs comparing DRA with TRA, with the primary outcome being total crossover to another access site, stratified by study era (up to vs after DISCO RADIAL trial). Secondary outcomes included crossover to femoral access and switch to another radial access, analyzed both in the overall population and among patients experiencing crossover. Frequentist and Bayesian meta-analyses were performed. Results: Twenty RCTs including 8868 patients (4414 DRA; 4454 TRA) were analyzed. Overall crossover was higher with DRA (odds ratio [OR] 2.78; 95 % confidence interval [CI]: 1.94, 3.98), but decreased after DISCO RADIAL (OR 2.14 vs 4.23 up to DISCO RADIAL). Among patients experiencing crossover, DRA was associated with a markedly lower risk of conversion to femoral access (OR 0.33; 95 % CI: 0.19, 0.59), with most switches redirected to another radial site. These findings were consistent across sensitivity and Bayesian analyses, with no evidence of major publication bias. Conclusions: DRA is associated with a higher overall crossover rate compared with TRA, but this risk has decreased over time. Importantly, when crossover occurs, DRA significantly reduces the likelihood of femoral conversion, thereby preserving the safety benefits of a radial-first strategy.