P4.06 DIFFERENTIAL EFFECTS OF NEBIVOLOL AND ATENOLOL ON CAROTID ARTERIAL WAVE INTENSITY

Abstract

Background The hemodynamic effects of the vasodilator β-blocker nebivolol may differ from those of a conventional agent. Wave intensity analysis can describe the energy transported by wavefronts in the arterial system in the direction of wave propagation. A non-invasive ultrasound-based technique [1] was used to compare the effects of nebivolol and atenolol on carotid arterial wave intensity in patients participating in a hypertension treatment study. Methods 38 hypertensive patients (age 63±11yrs, 21 female) took part in a double-blind randomised cross-over study. All received bendroflumethazide 2.5mg for 6 weeks in advance, and throughout the study. We compared effects of nebivolol 5mg and atenolol 50mg on the magnitude of the initial systolic forward compression wave (S), the protodiastolic forward decompression wave (D) (both generated by the heart), the reflected compression wave (c−1) and local wave speed. Results. The S and D waves were significantly smaller with atenolol than with nebivolol treatment but wave reflection and wave speed did not differ. Wave parameter Nebivolol (n=38) Atenolol (n=38) p S wave, kW m−2 s−2 735 (586, 1049) 612 (443, 885) 0.007 D wave, kW m−2 s−2 220 (183, 284) 164 (106, 225) 0.001 c−1 wave, kW m−2 s−2 122 (74, 168) 97 (76, 150) 0.4 Wave speed, ms−1 6.67 (5.70, 9.28) 6.61 (5.22, 8.40) 0.4 Medians (25th, 75th percentiles), * Wilcoxon’s signed rank test Conclusions: In hypertensive patients nebivolol has a more favourable effect than atenolol on left ventricular wave generation without increasing wave reflection.