OBJECTIVES: The aim of this study was to investigate the effects of the vasodilating ß-blocker nebivolol and the cardioselective ß-blocker metoprolol on nitric oxide (NO) levels at vascular graft endothelium and vasa vasorum compared to controls in patients undergoing coronary artery bypass graft surgery. METHODS: This was a prospective study. Fifty-five patients were divided into three groups: nebivolol group (group N, n = 23), metoprolol group (group M, n = 16), and control group (group A, n = 16). Group N received nebivolol 5 mg once daily, and group M received metoprolol 50 mg once daily for 15 days in the preoperative period. Control patients did not use ß-blocker therapy. Tissue samples of both left internal mammary artery (LIMA) and saphenous vein grafts were investigated for NO activity using immunohistochemical methods. RESULTS: Demographic characteristics and risk factors were similar between groups. We observed the highest NO activity in group N in both endothelial and vasa vasorum samples of LIMA and saphenous veins. NO activity of metoprolol group was similar to controls. CONCLUSIONS: According to our results, we think that nebivolol may be safer and preferable in order to diminish graft spasm in patients undergoing coronary artery bypass graft surgery due to the NO-mediated vasodilating effect.
Adrenergic beta-Antagonists/administration & dosage , Benzopyrans/administration & dosage , Coronary Artery Bypass , Ethanolamines/administration & dosage , Mammary Arteries/drug effects , Metoprolol/administration & dosage , Nitric Oxide/metabolism , Saphenous Vein/drug effects , Vasodilator Agents/administration & dosage , Aged , Case-Control Studies , Chi-Square Distribution , Coronary Artery Bypass/adverse effects , Drug Administration Schedule , Female , Graft Occlusion, Vascular/etiology , Graft Occlusion, Vascular/physiopathology , Graft Occlusion, Vascular/prevention & control , Humans , Male , Mammary Arteries/metabolism , Mammary Arteries/surgery , Middle Aged , Nebivolol , Prospective Studies , Risk Factors , Saphenous Vein/metabolism , Saphenous Vein/transplantation , Time Factors , Treatment Outcome , Turkey , Vasoconstriction/drug effects
