Radial artery characteristics before and after intra-arterial administration of nitroglycerin and verapamil: an optical coherence tomography study

Background Radial artery dimensions before and after intra-arterial vasodilator administration remain incompletely characterized along the vessel. This study used optical coherence tomography (OCT) to assess paired changes in mean lumen diameter. Methods Twelve patients underwent baseline OCT 5 min after limited sheath insertion and post-administration OCT after intra-arterial nitroglycerin and verapamil, before coronary angiography. The full OCT-imaged radial artery span was divided into equal proximal, middle, and distal thirds before selecting anatomically matched analyzable portions. Analysis included 1,482 matched cross-sectional pairs (2,964 frames), with a cumulative matched analyzable length of 1,404.4 mm. Measurements at matched 1-mm intervals were aggregated within patients. Mean lumen diameter was the representative lumen metric; area and volume were supportive measurements. Results Mean lumen diameter increased from 3.06 ± 0.49 to 3.35 ± 0.56 mm (mean paired change, 0.29 mm; 95% CI, 0.20–0.39; P < 0.001). The mean patient-level relative increase was 9.6%. Mean increases were observed in all three thirds in exploratory analyses. Conclusions Mean radial artery lumen diameter was greater after intra-arterial nitroglycerin and verapamil than at baseline. Clinical trial registration https://www.chictr.org.cn/hvshowproject.html?id=270,922&v=1.1 , Chinese Clinical Trial Registry (ChiCTR) ChiCTR2500097574.