Does sublingual 17β-oestradiol have any effects on exercise capacity and myocardial ischaemia in post-menopausal women with stable coronary artery disease?

Background A variety of vascular effects have been ascribed to 17 beta-oestradiol. These effects may partially explain the reduced incidence of cardiovascular disease found in post-menopausal women on oestrogen replacement therapy. Objectives To evaluate the effects of 2 mg sublingual 17 beta-oestradiol on exercise capacity, exercise-induced myocardial ischaemia and circulating levels of endothelin-1 in post-menopausal women with stable coronary artery disease. Methods Twelve post-menopausal women, mean age 61 (range 52-72) years, with angiographically verified significant coronary artery disease, were randomly assigned to 2 mg of sublingual 17 beta-oestradiol, 2.5 mg of buccal nitroglycerine and to placebo in a double-blind cross-over study design with at least 2 days between each of the study arms. Antianginal medications, with the exception of betablockers, were discontinued before investigation. All study patients underwent a maximal bicycle exercise test 30 min after drug intake. Blood was withdrawn immediately before and up to 8 h after medication for analyses of circulating levels of oestradiol and endothelin-1. Results The mean serum levels of oestradiol increased from a control level of 72 +/- 28 pmol . l(-1) to 3557 +/- 1631 pmol . l(-1)' after 30 min and to 5028 +/- 3971 pmol . l(-1) after 60 min with a gradual decline thereafter. Sublingual 17 beta-oestradiol did not induce any improvement in exercise duration when compared with nitroglycerin and placebo (500 +/- 112 s, 505 +/- 107 s, 498 +/- 157 s), and did not influence time to onset of ST-segment depression (358 +/- 89 s, 436 +/- 93 s: 384 +/- 116 s). The plasma levels of endothelin-l did not change after administration of 17 beta-oestradiol, nitroglycerin or placebo. Conclusions No effects on exercise capacity, exercise-induced acute ischaemia, or plasma levels of endothelin-1 were found after a single dose of 2 mg 17 beta-oestradiol in post-menopausal women with documented coronary artery disease.