Clinical determinants of radial artery caliber assessed at the time of transradial cardiac catheterization using routine prospective radiobrachial angiography

Background: Transradial coronary angiography/intervention (TRA/TRI) is associated with reduced rates of bleeding, vascular complications, and major adverse cardiovascular events as compared to the transfemoral approach, but remains underutilized in the United States (U.S.). Small radial caliber is often cited as a technical impediment, however radial artery diameter (RAD) has not yet been systematically studied in the U.S. population using routine, prospective radiobrachial angiography. Methods: Consecutive patients (pts) with radiobrachial angiography acquired during TRA/TRI from September 2015 to August 2016 were retrospectively analyzed. Quantitative angiography (QA) was performed on digital subtraction angiograms. RAD measurements at distal (dRAD), mid (mRAD), and proximal (pRAD) segments, as well as minimum (minRAD) and maximum (maxRAD) diameters were indexed to radial arterial sheath size and tabulated. RAD measurements were adjudicated by 2 expert operators. Descriptive statistics and regression analyses were performed using STATA (College Station, TX). Results: Of 175 radiobrachial angiograms, 2 were excluded due to uninterpretable QA. Woman had smaller RAD versus men: pRAD (3.11 vs 3.33 mm, p = 0.021), minRAD (2.36 vs 2.59 mm, p = 0.006), and maxRAD (3.32 vs 3.53 mm, p = 0.0195). Univariate analysis showed correlation between minRAD and gender (p = 0.012), age (p = 0.019), and weight (p = 0.008). However, after multivariate analysis, only gender was associated with minRAD (p = 0.05). Conclusion: This is the first study to describe the clinical determinants of RAD using prospective post-vasodilator, radiobrachial angiography in a U.S. population. Women had significantly smaller RAD across proximal, minimum, and maximum segments. Sex was the only multivariate predictor of minRAD.