Background: Oestrogen replacement therapy in postmenopausal women has a protective effect upon the cardiovascular system and improves exercise-induced myocardial ischemia. Although in hormone replacement schemes progestins are required to reduce the likelihood of uterine malignancies, little is known on the cardiovascular effect of progestins. The purpose of this study was to evaluate the effect of oestrogen replacement alone and two different estrogen-progestin replacement therapy schemes upon exercise induced myocardial ischemia.
Material and method: The study population included 18 female menopausal patients with coronary artery disease. After a baseline exercise test patients received conjugated equine estrogens (CEE) 0.625 mg alone for 30 days when they underwent a second exercise test and were randomized to receive in a cross-over design medroxyprogesterone acetate (MPA) either in continuous combined therapy (2.5 mg/daily) for 28 days or in cyclical therapy (10 mg o.d. from day 16 to day 28).
Results: After CEE alone two patients with a previously positive exercise test showed a negative exercise test. CEE increased time to 1 mm ST compared to baseline (352+/-185 vs 265+/-133 s, P<0.01). In the 2 pts in whom the exercise test was negative after CEE the test remained negative during continuous combined MPA therapy while become positive during cyclical MPA. CEE+continuous combined MPA increased both time to 1 mm ST and exercise time compared to baseline (386+/-165 vs 265+/-133 s, P<0.01 and 545+/-198 vs 465+/-186 s, P<0.05, respectively). No difference was found between baseline and CEE+cyclical MPA in either time to 1 mm ST or exercise time (268+/-164 vs 265+/-133 s, P=NS and 455+/-223 vs 465+/-186 s, P=NS, respectively).
Conclusion: Continuous combined therapy with CEE+MPA improves exercise-induced myocardial ischemia in female patients with coronary artery disease while the beneficial effect of CEE is reduced by cyclical therapy.