Methods for evaluating the effects of new hormone replacement therapy compounds on coronary artery disease.

The clinical effect of hormone replacement therapy (HRT) on cardiovascular disease, and whether this effect is altered by the formulation of estrogen or progestin studied, is an area of controversy. Use of clinical end points for these studies requires large numbers of subjects observed for several years and is time consuming and costly. The selection of clinically relevant surrogate endpoints, however, is complex, because many of the currently available modalities are not sensitive enough to identify subclinical coronary disease or disease progression. Moreover, many of the existing choices are invasive and may not be appropriate for repeated assessment of disease. This article reviews some of the available diagnostic tools, including measures of arterial structure and function, intravascular ultrasound, and electron-beam computed tomography, and assesses their ability to evaluate the presence and severity of atherosclerosis and the impact of HRT on coronary artery disease progression.