Carvedilol improves endothelium-dependent dilatation in patients with coronary artery disease

OBJECTIVE: Flow-mediated, endothelium-dependent dilatation (FMD) of the coronary and peripheral circulation is impaired by increased oxidative stress in patients with coronary artery disease (CAD). Carvedilol is a novel beta-blocker that also shows an antioxidant effect in vitro. However, the effect of carvedilol on endothelial dysfunction associated with established coronary atherosclerosis has not been examined in the clinical setting. METHODS: We studied 29 patients with CAD, including 17 with recent myocardial infarction and 12 with stable effort angina pectoris. Nineteen patients received carvedilol (10 with infarction and 9 with angina), and 10 were treated with placebo (7 with infarction and 3 with angina). We also studied 13 age- and sex-matched control subjects. Brachial FMD during reactive hyperemia and nitroglycerin-induced, endothelium-independent dilatation were assessed by high-resolution ultrasound. RESULTS: FMD was smaller in patients with CAD compared with controls, although nitroglycerin-induced dilatation was similar. Carvedilol significantly improved FMD after long-term treatment (5. 1% +/- 0.4% at baseline to 7.8% +/- 0.3% after 4 months; P <.01) but not after short-term treatment (5.1% +/- 0.4% at baseline to 5.0% +/- 0.7% after 2 hours). Placebo therapy had no effect on endothelial dysfunction. Neither carvedilol nor placebo had an effect on nitroglycerin-induced dilatation after short- and long-term treatment. Long-term carvedilol therapy also significantly decreased the plasma level of thiobarbituric acid-reactive substances compared with placebo (carvedilol, 5.8 +/- 0.4 nmol/mL to 4.6 +/- 0.3 nmol/mL, P <.01; placebo, 5.9 +/- 0.4 nmol/mL to 5.8 +/- 0.4 nmol/mL, P = not significant). CONCLUSION: These findings suggest that the improvement of endothelial function by carvedilol may be caused by its antioxidant activity.