Evaluation of the diameter of the distal radial artery at the anatomical snuff box using ultrasound in Japanese patients.

Catheter angioplasty or angiography via the distal access point of the radial artery (dRA), located at the anatomical snuff box, is a less invasive strategy for coronary intervention attracting considerable attention. Determining the diameter of the dRA is necessary to minimize the risk of artery occlusion and safely perform catheter intervention. This was a retrospective observational study including patients who underwent coronary angiography or coronary intervention at Aomori Kyoritsu Hospital, Aomori, Japan, between February 2018 and August 2018. The diameter of the dRA and the conventional access point of the radial artery (cRA) at the wrist of the patients were measured using ultrasound prior to angiography or interventional procedure. A total of 120 patients were analyzed. In male patients, the diameters of the cRA and dRA were 2.62 ± 0.60 mm and 2.04 ± 0.43 mm, respectively. In females, these diameters were 2.44 ± 0.51 mm and 1.96 ± 0.44 mm, respectively. Overall, the dRA was statistically significantly smaller than the cRA. However, variations were observed, with eight patients (6.7%) having a larger dRA than cRA. The diameter of the dRA indicated only that of the cRA. A multivariate analysis did not reveal factors associated with vessel diameter. The size and anatomy of the dRA varied considerably. Thus, it is difficult to predict the actual diameter of the artery. Customized selection of the size of the sheath and site of intervention is essential for each patient to safely perform ultrasound examination prior to cannulation.