Comparison of the effects of tibolone and estrogen replacement therapy on echocardiographic basic cardiac functions in post-menopausal women: a randomized placebo controlled study.

OBJECTIVES

This study is designed to investigate and compare the effects of synthetic steroid tibolone and HRT on systolic and diastolic heart functions in post-menopausal women.

METHODS

This prospective, randomized placebo controlled double blind study was conducted in a university clinic. Fifty-eight non-smoking, otherwise healthy post-menopausal women who did not receive any kind of HRT at least for 3 years within the onset of menopause were included in the study. The patients were randomly allocated to either 2.5 mg per day tibolone (OD, n = 18), daily combined 0.625 mg of conjugated estrogens 2.5 mg-1 of medroxy progesterone acetate pill (EP, n = 20) or a vitamin pill (n= 20) in a double blinded fashion. Their basic systolic and diastolic functions were investigated with HP Sonos-1000 echocardiography using standard positions and windows before and 6 months after the initiation of HRT.

RESULTS

Mean age, weight, length of post-menopausal period, heart rate, systolic and diastolic pressures were similar between the groups. At the initiation of the study all groups had similar echocardiographic measurements. However, at the end of 6 months, left ventricular end-systolic and -diastolic volumes were decreased significantly compared to pretreatment and placebo in both EP and OD treated groups. (55.5 +/- 18.4 and 53.7 +/- 19.1.8 ml; 109.9 +/-19.9 and 110.7 +/- 20.8 ml versus 74.5 +/- 14.9 and 142.7 +/- 19.1 ml, respectively; P < 0.05). Improvement in diastolic functions was significant in EP/OD groups compared to pre-treatment period and the placebo groups (E/A 1.34 +/- 0.1 and 1.38 +/- 0.1 versus 1.18 +/-.09, deceleration time 204 +/- 11.1 and 202.8 +/- 27.1 ms versus 237.6 +/- 26.9 ms, respectively). Besides increase in left ventricular mass adjusted for height, decrease in left ventricular relative wall thickness, and systemic vascular resistance were significant in EP and OD treated groups than placebo and the pre-treatment measurements. Although improved in both OD and EP groups, the changes in systolic and diastolic functions were significantly higher in the OD treated group. Based on our preliminary results, we may conclude that both EP and OD regimens may improve cardiac performance and age related dysfunctions.

CONCLUSION

The present results may further support that both OD and EP exert many direct effects on cardiovascular system other than metabolic changes regarding lipoproteins. The greater improvement in the OD group may be explained by its weak androgenic activity which is consistent with the in vitro data that androgens are potent relaxing agents on coronary arteries and restores cardiac myosin isoenzyme and ATPase patterns which mandates further clinical studies.