Original Article--Evaluation of Radial Artery Anatomy With Various Anatomical Variants in Patients Undergoing Transradial Catheterization.

Abstract

Objectives: This study aimed to determine the incidence of radial artery anomalies in a large cohort of patients undergoing TRA and to evaluate their specific impact as predictors of procedural failure and access site complications.

Methods: This prospective, observational, single-center study enrolled 1000 consecutive patients undergoing coronary angiography or intervention via TRA between 2022 and 2024. Radial artery anatomy was assessed using retrograde radial arteriography immediately following sheath insertion. Anatomical variants were categorized into high bifurcation (origin proximal to the cubital fossa), Radial artery loops (full 360-degree curvature), Tortuosity (curve of more than 45° in the vessel), Narrow calliber, Spasm, and Ulnar absent. Procedural success was defined by completion of the procedure via the initial radial access site. Binary logistic regression was used to identify independent predictors of procedural failure (crossover to alternate access).

Results: Radial artery anomalies were observed in 9.3% (n = 93) of the total cohort. High bifurcation (4.7%) was the most common variant, followed by loops (2.3%) and tortuosity (1.5%). Overall procedural success via the initial radial site was 93.8%. The presence of an anatomical anomaly was a highly significant independent predictor of procedural failure/crossover (Odds Ratio [OR]: 8.16; 95% CI: 4.29 to 15.52; P < 0.0001). Specifically, radial loops were associated with a failure rate of 32.3% ( p < 0.05). Furthermore, patients exhibiting anomalies had a significantly smaller mean RA diameter (2.54 ± 0.47 mm) compared to those with normal anatomy (2.76 ± 0.39 mm; P < 0.0001). Smaller radial artery diameter (OR: 0.38; P = 0.001) and older age (OR: 1.03; P = 0.005) also predicted failure.

Conclusion: Radial artery variants, particularly loops, are significant predictors of procedural crossover but remain rare (~2%) and are successfully negotiated in nearly two-thirds of cases. These findings do not support routine upfront radial angiography, which increases radiation exposure and costs without meaningfully improving success rates. Instead, a selective angiographic approach is recommended for challenging cases. While distal radial access (dTRA) is a promising alternative, its adoption is tempered by a steeper learning curve and smaller vessel calibers.