The aim of this study was to investigate the midterm effects of transradial coronary angiography (TRCAG) on the radial and brachial artery diameter, the vasodilator characteristics, as well as to assess the factors determining functional recovery.

This study included 136 consecutive patients who underwent TRCAG. The radial artery was evaluated with ultrasonography before and 1 month after the procedure.

The basal right radial artery diameter (2.97 ± 0.46 vs. 2.82 ± 0.51, p < 0.001), after flow-mediated dilatation (FMD; 3.18 ± 0.45 vs. 2.99 ± 0.54, p < 0.001) and after nitroglycerin-mediated dilatation (NMD; 3.32 ± 0.45 vs. 3.11 ± 0.54, p < 0.001), and the percentage change in diameter after FMD (7.50 ± 3.62 vs. 5.89 ± 3.04, p < 0.001) and NMD (12.42 ± 4.96 vs. 10.54 ± 4.47, p < 0.001) were significantly decreased 1 month after TRCAG. The mean basal diameter of the right brachial artery (4.41 ± 0.58 vs. 4.40 ± 0.58, p = 0.012) after FMD (4.61 ± 0.60 vs. 4.59 ± 0.59, p < 0.001) and the percentage change in diameter after FMD (4.53 ± 2.29 vs. 4.33 ± 2.56, p = 0.038) were significantly decreased 1 month after TRCAG. The number of catheters used (B = 0.372, p < 0.001, 95 % CI = 0.006–0.013), basal radial artery diameter (B = − 0.217, p = 0.001, 95 % CI = − 0.021– 0.006), presence of hypertension (B = − 0.151, p = 0.011, 95 % CI = − 0.015 − 0.002), and pain score (B = 0.493, p < 0.001, 95 % CI = 0.007 – 0.012) were independent predictors of radial artery FMD change in multivariate regression analysis. The number of catheters used (B = 0.378, p < 0.001, 95 % CI = 0.009 – 0.020), basal radial artery diameter (B = − 0.210, p = 0.010, 95 % CI = − 0.034 − 0.005), and pain score (B = 0.221, p < 0.001, 95 % CI = 0.002–0.011) were independent predictors of radial artery NMD change in multivariate regression analysis.

Basal radial artery diameter, the number of catheters used during TRCAG, and the pain perceived during the procedure seem to be important predictors of vascular functional changes after TRCAG.