Hormone replacement therapy in postmenopausal women: carotid intima-media thickness and 3-D volumetric plaque quantification

Abstract

Objective:The relationship between postmenopausal hormone replacement therapy (HRT) and the risk of stroke has been investigated in a number of epidemiological studies. However, data concerning the quantitative effects of HRT on carotid atherosclerosis, as measured by noninvasive ultrasound methods, are sparse. Methods: In the present case, we examined 55 postmenopausal women (mean age 57.6±4.2 years) who were treated for 4.7 years with estrogens, either alone ( n=11) or in combination with progestins ( n=44). They were compared to 46 control subjects without HRT who were matched for age, hypertension, and various other vascular risk factors. At the study onset and 1.5 years later, all participants were examined by Doppler ultrasound and B-mode sonography, and plaque visualization, intima-media-thickness (IMT) and volumetric quantification of carotid plaques was performed. Results: The HRT group had a significantly lower incidence of carotid plaques (18%) than the control group (61%). The mean IMT for the HRT subjects was 0.52 mm in the common carotid artery and 0.46 mm in the internal carotid artery, as compared to 0.68 and 0.62 mm, respectively, for the control subjects. No significant changes in IMT were found in either group. 3-D evaluation of carotid plaques showed increased plaque volume in women without HRT compared to women with HRT. Conclusion: We have obtained quantitative data using different noninvasive ultrasound techniques which demonstrate that women receiving HRT develop less severe carotid atherosclerosis, an effect which may be mediated by direct hormonal effects on the carotid wall and, in part, by the indirect influence of hormones on lipoproteins. HRT may, indeed, be more effective on existing atherosclerotic plaques.