570 Predictors of Radial Artery Size in Patients Undergoing Cardiac Catheterization - Insights from the Good Radial Artery Size Prediction Study (GRASP)

Abstract

A small percentage of patients undergoing cardiac catheterization or percutaneous coronary intervention (PCI) via the transradial approach develop permanent occlusion of the radial artery as a result of the procedure. Although the use of a sheath that is larger than the resting diameter of the radial artery is one of the risk factors for radial artery occlusion, radial artery size is not routinely assessed prior to catheterization. We designed a prospective, observational study to determine if there are reliable bedside predictors of radial artery size. Ninety patients presenting for elective PCI or diagnostic coronary angiography were studied with ultrasound prior to catheterization and the diameters of their radial, ulnar and brachial arteries were measured. We correlated these measurements with prespecified candidate variables in order to identify predictors of radial artery size. The mean internal diameters of the right radial, ulnar and brachial arteries were 2.41 +/− 0.61, 2.04 +/− 0.47 and 4.47 +/− 0.86 mm, respectively. Results for the left arm were similar. The right radial artery was larger in men than in women (2.56 vs. 1.83 mm, p<0.001) and smaller in patients of south Asian descent (1.89 vs. 2.54 mm, p<0.001). Radial artery diameter was correlated with wrist circumference (r2=0.36, p<0.001) and shoe size (r2=0.31, p<0.001). There was weaker correlation between radial artery diameter and height (r2=0.19, p<0.001), weight (r2=0.22, p<0.001), body mass index (r2=0.09, p=0.008), body surface area (r2=0.29, p<0.001) and no correlation with reverse Allen's time (r2=0.02, p=0.31). The independent predictors of radial artery diameter from a multiple linear regression were shoe size (r2=0.352, p<0.001), male sex (r2=0.027, p=0.078) and non-south Asian ancestry (r2=0.024, p=0.094). The final model r2=0.40 (p<0.001). Patients who experienced pain on sheath insertion or removal had smaller radial arteries than those who did not (1.87 vs. 2.57 mm, p<0.001). Patients with acute radial artery occlusion (4%) had smaller arteries than those without occlusion (1.96 vs. 2.45 mm, p<0.001). Radial artery occlusion is observed in patients with smaller arteries and patients with smaller radial arteries are more likely to experience pain on sheath insertion or removal. Shoe size, male sex and non-south Asian ancestry are independent predictors of radial artery size.