ESTROGEN AND CARDIOVASCULAR FUNCTION AFTER MENOPAUSE

Nonrandomized trials of postmenopausal estrogen replacement have shown a benefit in the prevention of coronary artery disease. Less clear ar e the specific mechanisms by which this occurs. Estrogen has beneficia l effects on the lipid profile, with significant elevations in high de nsity lipoprotein cholesterol and reductions in low density lipoprotei n cholesterol reported. Also, antioxidant properties have been ascribe d to estrogen. In addition, estrogen has been shown to prevent paradox ic vasoconstriction in atherosclerotic coronary arteries after acetylc holine and may have calcium channel-blocking and alpha(2)-inhibiting p roperties. Other proposed mechanisms of cardiovascular protection incl ude reductions in serum fibrinogen and increases in prostacyclin biosy nthesis. There is some evidence that cardiovascular biomechanics may b e mildly depressed after menopause and that estrogen may normalize the se changes by increasing ventricular contractility and, possibly, rela xation. Far less is known about the cardiovascular effects of progeste rone, but overall it does not appear that the less androgenic progesti ns substantially modify the effects of estrogen. Because more women >5 0 years old die of cardiovascular disease than any other cause, furthe r clinical investigations of the risks and benefits of estrogen replac ement and combined estrogen and progesterone therapy are clearly neede d.