Postmenopausal women and cardiovascular risk: impact of hormone replacement therapy.

The increased life expectancy of women living in industrialized countries is associated with an increase in diseases dependent or facilitated by a state of estrogen deficiency, such as cardiovascular and cerebrovascular diseases. Several studies have shown that estrogen replacement therapy reduces the occurrence of coronary and, perhaps, of cerebrovascular disease by nearly 50% in treated women compared with nonusers. These findings are supported by the evidence that estrogens have a beneficial effect on cholesterol metabolism and deposition, with contribution to the inhibition of atherosclerotic plaque formation in arterial walls and a direct effect on the vessel wall. In some cases, progestins may counteract the beneficial effect of estrogens on cardiovascular functions. More androgenic progestins may have a detrimental effect on vascular reactivity, whereas less androgenic progestins do not seem to reduce the beneficial effect of estrogens. Case-control and cohort studies have shown that estrogen progestin therapy is associated with a significant reduction in cardiovascular mortality and morbidity. The HERS study has added critical data about the cardioprotective effect of hormone replacement therapy in elderly women with proven coronary artery disease. However, HERS results are not applicable to the population of women commonly prescribed hormone replacement therapy, because the data have been gathered in a population of patients infrequently prescribed with this therapy. Large-scale, randomized studies are evaluating the effect of estrogen and estrogen-progestin replacement therapy on cardiovascular events in less compromised menopausal women. Until completion of these studies, hormone replacement therapy in women with increased cardiovascular risk should be viewed with neither enthusiasm nor fear.