Beneficial effect of oestrogen on exercise-induced myocardial ischaemia in women with coronary artery disease

Abstract

Oestradiol-17β causes relaxation of isolated coronary arteries and increases blood flow in several vascular beds in human beings and animals. Oestrogen replacement therapy is associated with a lower incidence of cardiovascular disease, but the acute effects of Oestradiol-17β on myocardial ischaemia are unknown. We have studied the acute effect of sublingual oestradiol-17β on exercise-induced myocardial ischaemia in eleven women (mean age 58 [SD 8] years) with coronary artery disease. The women did two treadmill exercise tests on separate days; 40 min before the test they took sublingual oestradiol-17β (1 mg) or placebo, in random order. Plasma Oestradiol-17β concentrations were confirmed to be higher after sublingual oestradiol-17β than after placebo (2531 [1192] vs 155 [168] pmol/L, p<0·001). Oestradiol-17β increased both time to 1 mm ST depression (456 [214] vs 579 [191] s, p<0·004; difference of medians 92 [95% Cl 46-254]) and total exercise time (569 [249] vs 658 [193] s, p<0·01; difference 54 [10-212]). Acute administration of oestradiol-17β therefore has a beneficial effect on myocardial ischaemia in women with coronary artery disease. This effect may be due to a direct coronary-relaxing effect, to peripheral vasodilation, or to a combination of these mechanisms. Oestradiol-17β may prove to be a useful adjunct to the treatment of angina in postmenopausal women with coronary heart disease.