Angiographic changes in radial artery narrowing following intra-arterial vasodilator administration during transradial neuroendovascular procedures

Background Radial artery (RA) narrowing or spasm is frequently encountered during transradial neuroendovascular procedures. Although intra-arterial vasodilators are commonly administered in this procedural context, angiographic changes in RA diameter during transradial approach have not been well characterized in neurointervention. This study aimed to evaluate angiographic changes in RA diameter observed during transradial neurointervention before and after vasodilator administration, and to explore clinical factors associated with these changes. Methods We retrospectively analyzed 67 transradial neuroendovascular procedures from a single-center cohort performed under general anesthesia. Intra-arterial nitroglycerin (2 mg) and verapamil (5 mg) were administered via a 4F radial sheath. RA diameters were measured angiographically after sheath insertion, before and after vasodilator administration, and clinical variables, anatomical features, and procedural factors were assessed. Results The mean minimum RA diameter increased from 1.60 ± 0.69 mm to 2.26 ± 0.69 mm after vasodilator administration, with a mean change of +0.66 ± 0.50 mm. The mean maximum RA diameter increased from 2.98 ± 0.65 mm to 3.21 ± 0.70 mm. Greater increases in the minimum RA diameter were observed in procedures complicated by radial artery spasm and in patients with hypertension. No major access-site complications including radial artery occlusion, pseudoaneurysm, or compartment syndrome occurred. One procedure required access-site crossover because of catheter entrapment. Conclusion Angiographic changes in RA diameter were observed following intra-arterial vasodilator administration during transradial approach. These findings provide observational insight into the dynamic nature of RA diameter during transradial access and may help inform procedural decision-making in clinical practice.