The Impact of Intravenous Versus Intra-Arterial Heparin Administration on Radial Artery Spasm During Transradial Coronary Angiography

Background/Objectives: Radial artery spasm (RAS) is an important complication during transradial coronary angiography that may negatively affect procedural success and reduce patient comfort. The aim of this study was to comparatively evaluate the effects of intravenous (IV) and intra-arterial (IA) heparin administration on the development of RAS. Methods: This prospective, case-control study included a total of 223 patients undergoing transradial coronary angiography. Patients were divided into two groups as received either IV heparin (n = 77) or IA heparin (n = 146). All patients received a standard dose of unfractionated heparin (5000 IU) and an IA spasmolytic cocktail consisting of 2.5 mg verapamil and 100 mcg nitroglycerin. RAS was defined as pain during the procedure, resistance during catheter manipulation, or the need for crossover. Logistic regression analysis and receiver operating characteristic (ROC) curve analyses were performed. Results: RAS developed in 40 of 223 patients (17.9%). The incidence of RAS was significantly higher in the IA heparin group than in the IV heparin group (22.6% [33/146] vs. 9.1% [7/77]; p=0.004). Crossover to femoral access due to severe spasm was observed only in the IA group (6.2% [9/146] vs. 0% [0/77]; p=0.026). Patients who developed RAS were younger, required a greater number of catheters, had longer angiography duration, and were exposed to a higher total radiation dose (p<0.05 for all). Correlation analysis demonstrated a positive association of RAS with the number of catheters used and IA heparin administration, and a negative association with age. In ROC analysis, IA heparin administration, number of catheters used, and angiography duration showed comparable performance in predicting RAS. In multivariable logistic regression analysis, IA heparin administration and the number of catheters used were identified as independent predictors of RAS. Conclusions: During transradial coronary angiography, intravenous heparin administration significantly reduces the frequency of RAS and the associated need for femoral crossover compared with intra-arterial administration. IV heparin may be considered an easily applicable and effective strategy in clinical practice to prevent RAS.