Aim of the RADAR study is to evaluate whether results of Allen's test in consecutive patients undergoing transradial coronary catheterization predict the occurrence of ischemic complications defined primarily as an increase of thumb capillary lactate and secondarily as a composite of local discomfort during and/or after the procedure, disability of the instrumented arm defined as perceived (subjective) or objective muscular weakness, need for surgical intervention or RA occlusion at any time within 30 days after catheterisation. Bleeding complications will be also monitored.