Hormone replacement therapy and distensibility of carotid arteries in postmenopausal women: A randomized, controlled trial

OBJECTIVE The study objective was to clarify in a randomized, controlled, o bserver-blind trial whether hormone replacement therapy (HRT) improves elas tic properties of the common carotid artery in women with signs of subclini cal atherosclerosis, especially in subgroups with increased risk, and wheth er less progestin enhances the effect. BACKGROUND Previous observational studies have yielded conflicting results on the influence of HRT on central arteries. Some studies reported improvem ent of distensibility by estrogen alone or in the subgroup of smokers. METHODS A total of 321 postmenopausal women were randomized to I mg 17 beta -estradiol plus 0.025 mg gestodene for 12 days every month (HRT 1), or 1 m g 17 beta -estradiol plus 0.025 mg gestodene for 12 days every third month (HRT 2), or no-HRT, during 48 weeks. In 173 women, distensibility of the co mmon carotid artery was determined before and after therapy by M-mode ultra sound and brachial blood pressure measurement. RESULTS Change of distensibility was small and similar in the three treatme nt groups. In the subgroup of current smokers, HRT 2 (low progestin) increa sed distensibility by 32% (HRT 2: 8.2 +/- 11.7; HRT 1: 0.6 +/- 6.0; no HRT: - 1.8 +/- 6.8 X 10(-3)/kPa, p = 0.025 for no-HRT vs. HRT 2). In the subgro ups with elevated blood pressure, high low density lipoprotein (LDL) choles terol, or high age, no effect of HRT was detected. CONCLUSIONS This randomized intervention study demonstrates that long-term HRT with estrogen and progestin does not substantially influence distensibi lity of central arteries. Yet, in currently smoking postmenopausal women, H RT with low progestin seems to improve distensibility; this merits further study in a specifically designed trial. (C) 2000 by the American College of Cardiology.