The clinical aspects of estrogen and the cardiovascular system.

Extensive epidemiologic and postmortem studies have identified a link between menopause and cardiovascular disease. The relation is especially strong in surgically menopausal women who do not receive estrogen replacement. More than 30 observational studies and one small randomized, controlled clinical trial have provided evidence that estrogen replacement reduces cardiovascular risk by approximately 50%. Four studies that used coronary arteriography to document the presence of coronary atherosclerosis have provided some of the most compelling evidence that estrogen replacement reduces cardiovascular risk in postmenopausal women. One study of survival in women undergoing coronary arteriography found that the greatest improvement in total mortality took place in those women with substantial coronary stenosis; less benefit was observed in those without disease. Angiographic studies have also confirmed the importance of high-density lipoprotein cholesterol in mediating the effect of estrogen and the beneficial effect of estrogen on endothelial function. Although the addition of progestins to estrogen attenuates estrogen's effect on high-density lipoprotein cholesterol, limited observational daa have suggested that the cardioprotective effect is not reduced.