Acute effect of oestrogen replacement therapy on treadmill performance in postmenopausal women with coronary artery disease.

Abstract

The significant reduction in cardiovascular morbidity and mortality following oestrogen replacement therapy in postmenopausal women is only partly explained by an improved lipid profile. Given acutely, oestradiol causes vasodilatation and increases coronary blood flow and, in large doses, improves treadmill performance in postmenopausal women with coronary artery disease. However, the significance of oestrogen-mediated vasodilatation is unknown since the acute effects of oestradiol in doses and preparations commonly used clinically have not been tested. The aim of this study was to evaluate the acute effects of conventional replacement therapy with 17 beta-oestradiol on treadmill performance in 16 postmenopausal women with angina in a randomized, double-blind, placebo-controlled cross-over trial. Following baseline treadmill testing a transdermal oestrogen patch releasing 50 micrograms oestradiol. 24 h-1 or matching placebo was applied and the exercise test repeated 24 h later. The patch was then removed. Seven to 14 days later the sequence was repeated using the alternative patch. The changes in time to angina, time to 1 mm ST segment depression and total exercise time for each treatment compared with the corresponding baseline test were calculated. Plasma 17 beta-oestradiol increased with active therapy from 56 +/- 30 pmol.l-1 to 204 +/- 90 pmol.l-1, indicating adequate replacement. Compared with their respective baseline exercise tests there were no differences between active and placebo patches for time to angina (active: 13 +/- 55 s vs placebo: 10 +/- 47 s), time to 1 mm ST segment depression (active: -30 +/- 52 s vs placebo: 24 +/- 71 s) or total exercise time (active: 14 +/- 45 s vs placebo: 13 +/- 35 s). Despite the recognized acute vasodilator action of larger doses of oestrogen, doses conventionally used in hormone replacement therapy had no acute effect on treadmill performance in this group of postmenopausal women with coronary artery disease.