Are calcium antagonists necessary to all patients with radial artery during offpump coronary surgery?

We have made distal radial artery pressure measurement and compared it to another preoperatively cannulated radial artery pressure in order to evaluate the necessity of calcium channel blockers during and after off-pump surgery.  If there was more than 20 mmHg gradients between two arms we decided to use calcium channel blockers. Significant pressure gradient (>20 mmHg) was detected in only two percent of our patients.