High resolution ultrasound assessment of the carotid artery: its relevance in postmenopausal women and the effects of tibolone on carotid artery ultrastructure.

ABSTRACT

OBJECTIVES: Hormone replacement therapy protects from cardiovascular disease at the menopause in part by reduction of menopausal pro-atherogenic serum lipid changes. Tibolone has beneficial effects on lipids, although serum high density lipoprotein levels decrease. This study aimed primarily to establish the effects of long-term administration of tibolone on a new surrogate marker for cardiovascular disease risk, the measurement of carotid artery intima-media thickness (CIMT) using high-resolution ultrasound. METHODS: Measurement of CIMT and assessment of carotid atherosclerotic plaques were undertaken in 31 women on tibolone and 30 voluntary controls from an ongoing open-label study of tibolone. RESULTS: The two groups were comparable, except for mean age and prevalence of current smokers. Repeatability of CIMT measurements was acceptable (CV, 10.0%). CIMT was significantly thicker in those with atherosclerotic plaques and increased systolic blood pressure. Prevalence of plaques was raised in those who had ever smoked, and those with elevated systolic blood pressure. There was no influence of tibolone on CIMT, whether plaques were present or not. CONCLUSIONS: This reliable technique demonstrates associations between CIMT and established risk factors. CIMT was significantly thicker in those with existing plaques. We did not demonstrate an effect of long-term tibolone use on either CIMT or prevalence of plaques.