Distal Radial Approach in Coronary Angiography Using a Transdermal Nitroglycerin Patch: Double-Blinded Randomized...

Nitroglycerin dilates the radial artery and prevents spasm, which increases the success rate of sheath cannulation through the conventional transradial approach. However, the effects of nitroglycerin on distal radial approach (DRA) procedures are not known. The aim of this study is to elucidate whether a transdermal nitroglycerin patch improves the rate of successful DRA cannulation. A total of 92 patients scheduled for coronary angiography by means of DRA randomly received (1:1) a transdermal nitroglycerin patch preintegrated with the covering material or only the covering material on their upper arm on the side of the puncture. The diameter of the distal radial artery was evaluated with ultrasound at baseline and after application. DRA procedures were performed in a double-blind fashion. The primary outcome was the rate of successful palpation-guided distal radial artery cannulation with the first puncture. The nitroglycerin group had larger distal radial artery diameter after patch application than that of the no-treatment group (mean, 3.21 mm vs 2.71 mm, p <0.001), but not at baseline (mean, 2.64 mm vs 2.64 mm, p = 0.965).The nitroglycerin group had a significantly higher success rate of DRA cannulation with the first puncture than that of the no-treatment group (59% vs 24%, p = 0.001; odds ratio 4.5, 95% confidence interval 1.9 to 11.0). The nitroglycerin group required fewer punctures than did the no-treatment group (median, 1 vs 3, p = 0.019). There were no significant differences in the occurrence of hypotension between the 2 groups. No patients experienced radial artery occlusion. In conclusion, transdermal nitroglycerin patch application safely facilitates DRA cannulation. Trial Registration: Japan Registry of Clinical Trials, https://jrct.niph.go.jp/ (identifier: jRCTs051210128).