The effects of hormone replacement therapy in normal postmenopausal women: Measurements of Doppler-derived parameters of aortic flow

In this study the effects of hormone replacement therapy on cardiac function in healthy postmenopausal women were evaluated by Doppler echocardiography that was performed before (T1) and 2.5 months after the initiation of hormone replacement therapy (T2) in the peak estrogenic phase. The following parameters of aortic flow were measured: peak flow velocity, acceleration time, and ejection time. Additional parameters were calculated: flow velocity integral and mean acceleration. The study group included 24 postmenopausal women aged 43 to 60 years (mean 51.6 years). The control group consisted of 19 postmenopausal women aged 46 to 60 years (mean 53.5 years) who were not receiving hormone replacement therapy and who underwent the same evaluation. There were no changes in all Doppler parameters between T1 and T2 in the control group. However, in the study group there were significant increases in peak flow velocity (108.3 ± 16.7 cm/sec at T1 vs 123 ± 20.7 cm/sec at T2; p = 0.002), flow velocity integral (17.7 ± 3.9 vs 21.5 ± 4.7 cm; p = 0.0003), mean acceleration (11.5 ± 1.9 vs 13.1 ± 2.6 m/sec/sec; p = 0.001), and ejection time (324 ± 37.6 vs 348.8 ± 40.7 msec; p = 0.002). There was no change in acceleration time (94.8 ± 6.6 vs 95 ± 10.9 msec). These results demonstrate that estrogens increase both stroke volume and flow acceleration. The latter probably reflects a combination of enhanced inotropism and vasodilatation. We assume that the cardioprotective effect of hormone replacement therapy in postmenopausal women may be due not only to changes in lipid profile but also to direct effects of estrogens on central and peripheral hemodynamic parameters.