Vascular Endothelial Function in Patients With Coronary Slow Flow and the Effects of Nebivolol

Abstract

Background: Brachial endothelial function has been associated with coronary slow flow (CSF). Increasing blood flow to brachial artery provokes endothelium to release nitric oxide (NO) with subsequent vasodilatation. Besides its beta 1-blocker activity, nebivolol causes vasodilatation by increasing endothelial NO release. Objective: To assess the effects of nebivolol on vascular endothelial function in patients with CSF Methods: Forty-six patients with CSF and 23 individuals with normal epicardial coronary arteries were examined with transthoracic echocardiography and brachial artery ultrasonography. The patients were reevaluated two months after treatment with aspirin or aspirin plus nebivolol. Results: Patients with CSF had higher body mass index (26.5 +/- 3.3 vs. 23.8 +/- 2.8, p < 0.001), mitral inflow isovolumetric relaxation time (IVRT) (114.9 +/- 18.0 vs. 95.0 +/- 22.0 msec, p < 0.001) and lower left ventricular ejection fraction (LVEF) (63.5 +/- 3.1% vs. 65.4 +/- 2.2, p = 0.009), HDL-cholesterol (39.4 +/- 8.5 vs. 45.8 +/- 7.7 mg/dL, p = 0.003) and brachial flow-mediated dilatation (FMD) (6.1 +/- 3.9% vs. 17.6 +/- 4.5%, p < 0.001). Mere were significant correlations between FMD and the presence of CSF(r = 0.800, p < 0.001) and HDL-cholesterol (r = 0.349, p = 0.003). Among Patients with CSF, although pretreatment mean FMD values were similar (6.1 +/- 4.3% vs. 6.0 +/-,6%, p = 0.917) compared to aspirin alone group, posttreatment FMD was significantly higher in patients treated with aspirin plus nebivolol (6.0 +/- 3.5% vs. 8.0 +/- 2.9%, p = 0.047). Treatment with nebivolol was associated with a significant increase in FMD (6.0 +/- 3.6 to 8.0 +/- 2.9 %, p = 0.030) whereas treatment with aspirin alone was not. Conclusion: Endothelial function may be impaired in both coronary and brachial arteries in patients with CSF and nebivolol may be effective in the improvement of endothelial function in patients with CSF. (Arq Bras Cardiol 2011;97(4):275-280)