Pre-Procedural Vascular Phenotyping Is Associated with Radial Artery Functional Impairment After Transradial...

Background/Objectives: Transradial access (TRA) is the preferred route for coronary catheterization, yet its consequences for radial artery vasoreactivity and hemodynamic parameters remain incompletely characterized. We prospectively quantified TRA-induced functional impairment, its clinical determinants, and the association of baseline parameters with post-procedural outcomes. Methods: Ninety-four consecutive patients undergoing elective TRA were assessed at baseline, 24 h, and one month using high-resolution Doppler ultrasound. Nine vascular parameters were measured: flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), peak systolic velocity (PSV), resistive index (RI), pulsatility index (PI), resting and hyperemic velocity-time integral, hyperemic blood flow volume, and lumen diameter. Non-parametric methods were applied throughout. Results: FMD declined at 24 h (-31.2%; p < 0.001) and showed no significant recovery at one month (p = 0.08 vs. 24 h). NMD showed a greater acute decline (-36.6%; p < 0.001) with partial but statistically significant recovery at one month (p < 0.001). PSV recovered fully by one month; RI fell below baseline, consistent with compensatory microvascular vasodilation. Radial artery lumen diameter remained significantly below baseline at one month. Radial artery occlusion occurred in 4 patients (4.3%), all with spontaneous recanalization. Female sex was selectively associated with greater NMD reduction (ΔNMD -8.3% vs. -5.8%; p = 0.005) without a statistically significant FMD difference (p = 0.40). Older age correlated with impaired FMD recovery at one month (ρ = -0.62; p < 0.001) but not with NMD outcomes. Baseline PSV demonstrated the highest discriminatory performance for significant FMD decline (AUC = 0.73). Conclusions: TRA causes multidomain, persistent radial artery functional impairment at one month, with distinct recovery trajectories for endothelial and smooth muscle function. Female sex and advanced age are selective determinants of injury and recovery, respectively. A pre-procedural phenotype comprising baseline diameter, PSV, RI, and age is associated with post-procedural outcomes and supports further investigation of pre-procedural phenotyping as a candidate framework for risk stratification.