Postmenopausal hormone replacement therapy and the vascular wall: Epidemiology and clinical studies

The clinical relevance of estrogen's multiple acute and more delayed effect s on vascular wall structure and function is incompletely understood This r eview attempts to reevaluate epidemiological findings and clinical studies concerning the vascular actions of estrogens and gives implications for str ategies in postmenopausal hormone replacement therapy (HRT). There is large evidence from observational studies that HRT reduces the risk of cardiovas cular mortality and morbidity in postmenopausal women. However according to the only large randomized, placebo-controlled, secondary prevention Heart and Estrogen/progestin Replacement Study (HERS), women with prevalent cardi ovascular disease (CVD) have increased CVD events within the first year aft er onset of HRT The net effects of HRT on atherosclerosis, coagulation, fib rinolysis or the inflammatory response are unproven. Randomized trials of i ntermediate outcomes reveal that HRT has favorable effects on isolated card iovascular risk factors, e.g. lipoproteins, carbohydrate metabolism and vas odilatation, but the impact of this effects on clinical endpoints is still not cleat: The basis of "evidenced based medicine" is currently not suffici ent to provide exact recommendation who will benefit from HRT and who might not. Therefore, the decision about hormone use should consider individual benefit-risk profiles.