Assessment of the efficacy of phentolamine to prevent radial artery spasm during cardiac catheterization procedures: a randomized study comparing phentolamine vs. verapamil.

The objective of this study was to evaluate phentolamine as radial artery spasmolytic in transradial catheterization procedures. Radial artery spasm is a relatively frequent complication during transradial approach, causing patient discomfort or even making it impossible to continue the procedure. As radial artery spasm is mediated by the stimulation of alpha-adrenoreceptors, the use of the alpha-blocker phentolamine could make sense as spasmolytic. We designed a randomized double-blind study to compare phentolamine vs. verapamil, the standard spasmolytic agent. Five hundred patients (250 in each arm) submitted to a transradial cardiac catheterization were consecutively included and randomly assigned to receive 2.5 mg of verapamil or 2.5 mg of phentolamine after sheath insertion. Both vasodilator agents induced a significant radial artery diameter increase (from 2.22 +/- 0.53 to 2.48 +/- 0.57 mm, P < 0.001 for verapamil, and from 2.20 +/- 0.53 to 2.45 +/- 0.53 mm, P < 0.001 for phentolamine). However, verapamil was more efficacious to prevent radial artery spasm (13.2% compared with 23.2% in phentolamine-treated patients; P = 0.004). Follow-up (20 +/- 18 days) evaluation of the radial artery patency by plestismography and pulse oximetry showed no differences between the two groups in the rate of radial occlusion (3.0% vs. 3.2% in verapamil and phentolamine treated patients, respectively). Phentolamine was an effective radial vasodilator agent, although it showed less ability to prevent radial artery spasm than verapamil. Radial artery occlusion rate was almost identical for both vasodilators. Thus, phentolamine could be a valid alternative to verapamil as a radial artery spasmolytic agent.