ACUTE EFFECTS OF CONJUGATED ESTROGENS ON CORONARY BLOOD-FLOW RESPONSETO ACETYLCHOLINE IN MEN

Estrogen therapy is associated with a 50% reduction in the clinical ma nifestations of coronary artery disease in postmenopausal women. Atten uation of coronary vasomotor dysfunction may contribute to estrogen's cardio-protective effects. We hypothesized that conjugated estrogens, which contain several vasoactive estrogenic compounds, may favorably i nfluence the vasomotor response to acetylcholine in men. Twenty men, 5 6 +/- 5 years of age, referred for clinically indicated coronary angio graphy, participated in this study. Acetylcholine-induced changes in c oronary flow were measured by quantitative coronary angiography and in tracoronary Doppler ultrasonography before and 15 minutes after intrav enous administration of conjugated estrogens (0.625 mg) in 12 men and placebo in 8 men. Initial acetylcholine infusion resulted in no signif icant increase in coronary blood flow. However, 15 minutes after estro gen administration repeat acetylcholine infusion caused a mean 32% inc rease in coronary blood flow from 41 +/- 5 to 54 +/- 8 ml/min (p = 0.0 2). Acetylcholine-induced change in flow after estrogen was significan tly different from that before estrogen (p = 0.03). Placebo administra tion did not affect acetylcholine-induced changes in coronary flow. Th us, intravenous conjugated estrogens favorably modulate acetylcholine- induced changes in coronary hemodynamics in men. This suggests that no vel nonfeminizing estrogenic compounds may have anti-ischemic effects in men. (C) 1997 by Excerpta Medica, Inc.