Radial artery diameter does not correlate with body mass index: A duplex ultrasound analysis of 1706 patients undergoing trans-radial catheterization at three experienced radial centers

Background: We examined whether the radial artery diameter is correlated with body mass index (BMI) in patients undergoing transradial catheterization.

Methods: 1706 patients undergoing trans-radial catheterization at three experienced, high-volume, radial centers were analyzed. Radial and ulnar artery diameters were determined by ultrasound in the distal third of the forearm one day post procedure. Pearson correlation test was used to measure the relationship between continuous variables.

Results: Radial diameter was larger than the ulnar artery [median 2.8mm (interquartile range (IQR): 2.4-3.1mm) vs. median 2.4mm (IQR: 2.1-2.6mm), p<0.001]. Women had smaller radial and ulnar arteries compared to men [median 2.6mm (IQR: 2.3-2.9mm) vs. median 2.8 (IQR: 2.4-3.2mm), p<0.001 and median 2.2mm (IQR: 2.0-2.5mm) vs. median 2.5mm (IQR: 2.2-2.7mm), p<0.001, respectively]. There was no correlation between radial diameter and BMI (Pearson correlation=0.003, p=0.88 (2-sided)), but a strong linear correlation between the radial and ulnar artery diameter existed (Pearson correlation=0.48, p<0.001 (2-sided)). After adjustment for clinical variables including diabetes, gender, and age, female gender was associated with smaller radial diameter (<2.8mm) (odds ratio 1.72; 95% CI 1.40-2.12, p<0.001).

Conclusions: No correlation was observed between radial artery diameter and BMI, although female gender was associated with smaller radial diameter. This suggests catheterization can be performed without anthropometric consideration, although it should be recognized women may have smaller radial arteries. As the diameter of the radial is larger than the ulnar artery, the radial should remain the default catheterization access-site.