Aortic elastic properties : effects of carvedilol versus nebivolol

The aim of this study was to compare the effects of the new generation β-blocker anti-hypertensive drugs carvedilol and nebivolol on aortic elastic properties which are important indicators of hypertension-related morbidity and mortality.

A total of 50 patients who had been diagnosed with stage 1 hypertension according to the Joint National Committee (JNC) VII criteria and who had not received any anti-hypertensive treatment were enrolled in this study. Patients were randomized to receive either 25 mg/day carvedilol (n=25) or 5 mg/day nebivolol (n=25) for 3 months at the beginning of the study. Three patients (1 in the carvedilol group, 2 in the nebivolol group) who did not attend 3 month follow-up measurements were excluded from the study. The study was completed with 47 patients (25 women; mean age: 49 ± 9 years). The aortic elastic parameters such as aortic strain (AS), aortic distensibility (AD), and aortic stiffness index (ASI) were measured by echocardiography.

Carvedilol and nebivolol provided a similar decline in both systolic and diastolic blood pressures (-12/-7 mmHg, p<0.0001 and -12/-7 mmHg, p=0.002, respectively). Both carvedilol and nebivolol induced a significant decrease in heart rate (-15 bpm, p<0.0001, -17 bpm, p<0.0001, respectively). Even though the heart rate at the end of the treatment was lower for the nebivolol group, the rate of decrease of heart rates between carvedilol and nebivolol groups was not statistically significant (p=0.074). Both groups demonstrated improvements in the diastolic functions of the left ventricle where certain values showed more improvement for the nebivolol group. Both groups showed improvements in AS and AD rates compared to basal rates; however, these improvements were not statistically significant. Although the improvement rates in AS, AD, and ASI were higher in the nebivolol group compared to the carvedilol group, the differences were not statistically significant (p=0.091, p=0.095, p=0.259, respectively).

Both carvedilol and nebivolol induced a decrease in blood pressure and heart rate and showed an improvement in left ventricular diastolic functions. It was observed that both drugs did not cause deterioration in the aortic elastic properties but a slight improvement was seen. However, this improvement was not statistically significant. The improvement was more explicit in the nebivolol group. It may be concluded that nebivolol is slightly superior to carvedilol in reducing heart rate and improving left ventricular diastolic functions. However, further long-term studies with larger sample sizes should be performed in order to better define the effects of both drugs.