Choice of medication for radial artery vasodilation in patients awaiting coronary artery bypass grafting

Background: In this study, the vasodilatory effects of calcium antagonists and beta-blockers were investigated. Methods: After obtaining Faculty Ethics Committee approval and written informed consent from the patients, 72 adult patients (50 males, 27 females; mean age 62.9 +/- 9.3 years; range 37 to 75 years) who will undergo elective coronary artery bypass grafting (CABG) surgery were included in this study. We evaluated the vasodilatory effect of diltiazem alone (group 1), nifedipine alone (group 2), amlodipine alone (group 3), nebivolol alone (group 4) and nifedipine in combination with metoprolol (group 5). Seventy-seven patients who would undergo isolated CABG using radial artery were prospectively randomized to oral agents four or five days before operation. The dilatation of the lumen diameter and area of the radial artery were evaluated with high-resolution ultrasonography just before and 4-5 days after medical treatment. Results: Diltiazem alone group (p=0.058) and niphedipine in combination with metoprolol group (p=0.067) did not show a significant increase in the lumen diameter and area after medical treatment compared to the pretreatment values. Statistically significant increases in lumen diameter and area were observed in nifedipine (p=0007), amlodipine (p=0.003) and nebivolol (p=0.047) groups. Conclusion: Our results demonstrate that calcium channel antagonists are not equally effective in radial artery vasodilatation. Nifedipine, amlodipine and nebivolol appear to be the most effective agents in reducing radial artery spasm. Nebivolol is a beta-blocker and also has a potent vasodilatory effect on radial artery vasospasm.