There is an uncertainty regarding the anatomical size differences between distal radial access and conventional transradial access sites. In a systematic review and meta-analysis presented at the EuroPCR 2026, investigators quantified radial artery diameters at both access locations and evaluated demographic and regional variations.

The analysis included studies comparing arterial diameter measurements at distal radial access and conventional transradial access puncture sites. Random-effects models and Bayesian analyses were used to evaluate the consistency and robustness of findings.

Findings

• A total of 38 studies involving 12,249 patients were included in the pooled analysis.
• The mean arterial diameter at the conventional transradial access site was 2.57 ± 0.53 mm.
• The distal radial artery was consistently smaller than the conventional radial artery by a mean difference of −0.36 mm (95% CI −0.41 to −0.31).
• The anatomical difference corresponded to approximately one French sheath size.
• No significant differences were observed according to study design.
• Regional variation was identified, with larger arterial diameters reported in North American populations and smaller diameters in Asian populations.
• Distal radial measurements obtained at the dorsum of the hand were smaller than those measured at the anatomical snuffbox.
• In sex-specific analyses, both distal and conventional radial artery diameters were larger in men than in women.
• Women’s conventional transradial artery diameters were similar to men’s distal radial artery diameters.

The findings demonstrate that distal radial access sites are anatomically smaller than conventional radial access sites, which may have important procedural implications for sheath selection and vascular complications.