Pre-Procedural Vascular Phenotyping Predicts Radial Artery Functional Impairment After Transradial Catheterization

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 predictive val-ue of baseline parameters. Methods: Ninety-four consecutive patients undergoing elective TRA were assessed at baseline, 24 hours, 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, hyper-emic blood flow volume, and lumen diameter. Non-parametric methods were applied throughout. Results: FMD declined at 24 hours (−31.2%; p< 0.001) and showed no sig-nificant recovery at one month (p=0.08 vs 24 hours). NMD showed a greater acute de-cline (−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 selectively predicted greater NMD reduction (ΔNMD −8.3% vs −5.8%; p=0.005) without a corresponding 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). Conclu-sions: 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, re-spectively. A pre-procedural phenotype comprising baseline diameter, PSV, RI, and age predicts post-procedural outcomes and supports further investigation of pre-procedural phenotyping for risk stratification.