Aims: To compare the effect of low (0.3 mg) and commonly prescribed (0.625 mg) doses of conjugated equine estrogens (CEE) on brachial artery flow-mediated dilation and lipid profiles.
Methods and results: Twenty-five postmenopausal women (mean age, 65+/-6 years) at risk for coronary artery disease (CAD) (> or =2 established risk factors) entered a double-blind crossover study. Brachial artery endothelial function was evaluated by means of high-resolution vascular echography. Both CEE doses significantly decreased total cholesterol (-13%, 0.3 mg; -15%, 0.625 mg), low-density lipoprotein-cholesterol (LDL-C) (-15%, 0.3 mg; -16%, 0.625 mg), and lipoprotein(a) (-28%, 0.3 mg; -39%, 0.625 mg) values from baseline levels. Both treatments increased high-density lipoprotein-cholesterol (HDL-C) (5%, 0.3 mg; 7%, 0.625 mg) and triglycerides (3%, 0.3 mg; 8%, 0.625 mg). There was no dose effect for changes in the LDL-C/HDL-C ratio (-21%, 0.3 mg; -23%, 0.625 mg). Both doses improved brachial artery dilation during reactive hyperemia by 63% over baseline.
Conclusion: In women at risk for CAD, low-dose hormone replacement treatment (HRT) improves lipid profiles and brachial artery endothelial function comparably to the most commonly prescribed dose. The benefit:risk ratio of low-dose HRT provides an attractive option for postmenopausal women at risk for CAD.