Impaired forearm blood flow and vasodilator reserve in healthy postmenopausal women.

BACKGROUND: The natural process of cessation of ovarian estrogen production is associated with an increasing incidence of cardiovascular disease.
OBJECTIVE: We aimed to determine whether postmenopausal women had menopause-associated vasomotor disturbances develop.
METHODS: We studied the vascular forearm function using strain-gauge venous occlusion plethysmography in 12 healthy postmenopausal women (mean age +/- SD, 47 +/- 3 years; time-lapse from menopause >1 year). Twelve premenopausal subjects matched for age and biophysical characteristics were used as a control group.
RESULTS: No differences were observed in heart rate or mean blood pressure between the 2 groups of women. Forearm blood flow at supine resting was lower in postmenopausal than in premenopausal women (2.4 +/- 0.8 vs 3.1 +/- 0.5 mL/100 mL/min; P <.05). Local vascular resistance was higher in postmenopausal than in premenopausal women (43.5 +/- 17.5 vs 31.1 +/- 4.3 mm Hg/mL/100 mL/min; P <.05). Moreover, peak forearm flow in response to forearm ischemia was 20.8 +/- 7.9 mL/100 mL/min in postmenopausal women and 26.6 +/- 9.7 mL/100 mL/min in premenopausal women (P <.01). Plasma concentration of noradrenaline in the supine position was significantly higher in postmenopausal than in premenopausal women (286 +/- 22 pg/mL vs 195 +/- 33 pg/mL; P <.01). Finally, a significant positive relation was revealed in postmenopausal women between the amount of vasodilator reserve (D flow) in local peripheral circulation and levels of circulating estradiol-17beta.
CONCLUSIONS: Abnormalities observed in forearm blood flow and vasodilator capacity in postmenopausal women may be attributed to a critical loss of the vasodilating property of physiologic estrogen. Our data support the possibility that reduction in dilator capacity of the vasculature may contribute to the increase of cardiovascular disease after menopause.