Radial artery spasm (RAS) remains the major limitation of transradial approach for percutaneous coronary interventions (PCI). We have previously demonstrated efficacy of verapamil to reduce RAS but recently, supply problems have occurred and many cathlab have changed verapamil to another calcium channel blocker, diltiazem. However, only poor data are known about safety and efficacy of diltiazem in this setting. The aim of our study was to evaluate the safety and efficacy of different vasodilators in the prevention of RAS during transradial PCI.

332 patients were consecutively randomized to blindly receive diltiazem 5 mg (n =117), verapamil 2.5 mg (n=109), or isosorbide dinitrate 1 mg (n =106) in three centers (Paris, France). All study drugs were administrated through the arterial sheath. The primary end point was the occurrence of a severe RAS defined by the operator as severe limitation of the catheter movement, with or without angiographic confirmation. Secondary endpoints included minor RAS, safety events (need for vasopressor, fluids, atropine support) and pain assessment scale.

Main characteristics including age, sex, weight, height, diabetes, arterial sheath diameters, and number of coronary catheters used were identical across the three groups. The rate of severe RAS was lowest in patients receiving isosorbide dinitrate (n=4, 3.8%), and verapamil (n=6, 5.5%), compared to diltiazem (n=12, 10.3%) but the difference was not statistically significant (p=0.128). The same results were found for minor RAS, respectively 17.4%, 16.0% and 25.6% (p=0.147). There was also no significant difference in term of safety events and pain sensation between the different groups. PCI was successful for all patients and no switch to transfemoral was reported in the entire population.

Frequency of severe RAS tended to be higher in patients receiving diltiazem compared to verapamil and isosorbide dinitrate during transradial procedures.