Nitroglycerin, nitroprusside, or both, in preventing radial artery spasm during transradial artery catheterization

Radial artery spasm remains a major complication of transradial coronary interventions. The aim of this study was to compare the efficacy of three different intra-arterial vasodilating cocktails in reducing the incidence of radial artery spasm in patients undergoing transradial coronary angiography. The secondary goal was to assess the predictors of arterial spasm in this large group of patients.

A total of 379 patients undergoing the procedure were randomly enrolled in 1 of 3 groups. Every patient in each of the 3 groups received intra-arterial heparin, lidocaine and diltiazem. Along with that, patients in Group A received nitroglycerin; patients in Group B received nitroprusside instead of nitroglycerin; and patients in Group C received both nitroglycerin and nitroprusside. A single experienced operator, blinded to the study drug, subjectively determined the presence of spasm.

Of 379 patients, a total of 44 patients (11.6%) experienced spasm. The occurrence of spasm was similar, independent of the vasodilator cocktail used (Group A: 12.2%, Group B: 13.4%, Group C: 9.5%; p = 0.597). After multivariate analysis, the following variables were found to be independent predictors of spasm: radial artery diameter (RD)/height index (p = 0.005), RD/BSA index (p = 0.012), and sheath outer diameter (OD)/RD index (p = 0.024).

In this prospective, randomized trial, the addition of a direct nitric oxide donor to nitroglycerin in an antispastic cocktail did not reduce the risk of spasm, and the use of nitroglycerin was found to be as effective as nitroprusside. Also, morphometric and mechanical factors play a significant role in predicting the occurrence of radial spasm. The sex of the patient, presence of diabetes, body surface area and smoking history appeared to play no role in predicting the occurrence of radial spasm.