Distal radial approach using a transdermal nitroglycerin patch : double-blinded randomized trial

Abstract Background The distal radial approach (DRA) provides a lower risk of radial artery occlusion than the conventional transradial approach (TRA) and has recently been used worldwide as an alternative access route for coronary catheterization. However, the small diameter of the distal radial artery causes difficulty in puncture and leads to DRA failure. Purpose The aim of this study is to elucidate whether a transdermal nitroglycerin patch improves the rate of successful DRA cannulation. Methods A total of 92 patients with angina pectoris scheduled for elective coronary angiography via DRA randomly received (1:1) a transdermal nitroglycerin patch pre-integrated 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-blinded fashion. The primary outcome was the rate of successful palpation-guided distal radial artery cannulation with the first puncture. Results The nitroglycerin group had larger distal radial artery diameter after patch application than the no-treatment group (3.21 ± 0.68 mm vs. 2.71 ± 0.52 mm, P<0.001), but not at baseline (2.64 ± 0.48 mm vs. 2.64 ± 0.45 mm, P = 0.965, Figure 1).The nitroglycerin group had a significantly higher success rate of palpation-guided DRA cannulation with the first puncture than the no-treatment group (58.7% vs. 23.9%; P = 0.001; odds ratio, 4.5; 95% confidence interval, 1.9–11.0, Figure 2). Fewer punctures were required for successful sheath insertion in the nitroglycerin group compared with the no-treatment group (1 [1–5] vs. 3 [2–6]; P=0.019). Procedure time from puncture to sheath insertion was shorter in the nitroglycerin group, but the difference was not significant (142 [112–287] seconds vs. 202 [142–411] seconds; P=0.058). The incidence of vasospasm, hypotension (systolic blood pressure < 90 mmHg) before and during CAG, and puncture site hematoma was similar in the two groups. No patients experienced distal radial arterial occlusion. Conclusions The use of a transdermal nitroglycerin patch was associated with an increase in the diameter of the distal radial artery, higher success rate of DRA cannulation with the palpation-guided first puncture. The transdermal nitroglycerin patch has a potential to be an effective pretreatment for DRA.Changes in distal radial artery diameterResults of primary outcome