Arterial vascular compliance in pre- and post-menopausal women and the effect of short-term estrogen replacement.

Post-menopausal women have increased risk for cardiovascular disease, possibly due to decreased production of estrogen. Hormone replacement therapy (HRT) may reduce cardiovascular events, but the effect on blood vessels has not been documented. Arterial compliance was studied using pulse contour computer analysis of non-invasively obtained radial artery wave forms. Capacitive compliance (C1) (large arteries) and oscillatory compliance (C2) (small arteries) was calculated using a modified Windkessel model. In order to assess the effects of menopause and estrogens on C1 and C2, 4 groups (G) of subjects were studied. G3 subjects were treated with estrogen (premarin 0.625 mg/day) for one month and studies repeated. Therefore post-menopausal women exhibit a lower arterial compliance and higher MAP and SVR than pre-menopausal women. Short-term estrogen increases small artery compliance, a possible contributor to the favorable effects of HRT on cardiovascular events.