BENEFICIAL EFFECT OF ESTROGEN ON EXERCISE-INDUCED MYOCARDIAL-ISCHEMIA IN WOMEN WITH CORONARY-ARTERY DISEASE

Oestradiol-17beta 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-17beta on myocardial ischaemia are unknown. We have studied the acute effect of sublingual oestradiol-17beta 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-17beta (1 mg) or placebo, in random order. Plasma oestradiol-17beta concentrations were confirmed to be higher after sublingual oestradiol-17beta than after placebo (2531 [1192] vs 155 [1.68] pmol/L, p<0.001). Oestradiol-17beta increased both time to 1 mm ST depression (456 [214] vs 579 [191] s, p<0.004; difference of medians 92 [95% CI 46-254]) and total exercise time (569 [249] vs 658 [193] s, p<0.01; difference 54 [10-212]). Acute administration of oestradiol-17beta 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-17beta may prove to be a useful adjunct to the treatment of angina in postmenopausal women with coronary heart disease.