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Effects of estradiol and the angiotensin II receptor blocker irbesartan on vascular function in postmenopausal women

2008; Lippincott Williams & Wilkins; Volume: 15; Issue: 1 Linguagem: Inglês

10.1097/gme.0b013e318150d13e

1530-0374

Faryal Mirza, Paul Jau Lueng Ong, Peter Collins, Kyoko Okamura, Marie Gerhard‐Herman, Gordon H. Williams, Ellen W. Seely,

Estrogen and related hormone effects

In Brief Objective: Estradiol and angiotensin receptor blockers have prominent effects on the renin-angiotensin-aldosterone system. The purpose of this study was to determine whether irbesartan, an angiotensin receptor blocker, has a greater effect on vascular function when combined with estradiol, compared with irbesartan alone, in hypertensive postmenopausal women. Design: Fifty-one women were studied while off any antihypertensive medications or hormone therapy at baseline and after randomization to one of four treatment arms for 12 weeks: (1) irbesartan and estradiol, (2) irbesartan and placebo, (3) estradiol and placebo, and (4) placebo/placebo. Estradiol and placebo arms served as control groups. Blood pressure, brachial reactivity, aldosterone, insulin, glucose, 24-hour urinary catecholamines, urinary sodium, and creatinine were measured. Fisher's exact test was used for comparison of differences in blood pressure in the treatment arms. Paired t test and analysis of variance were also performed for within- and between-group analysis. Results: A significantly larger number of women in the irbesartan and estradiol group had a decrease of 5 mm Hg or more in both systolic and diastolic blood pressures (P < 0.05) compared with irbesartan alone group. Forearm vascular reactivity was increased significantly compared with baseline (P < 0.05), and there was a significant decrease in the serum aldosterone level after treatment compared with baseline (P < 0.05) in the irbesartan and estradiol combination group. Fasting glucose and insulin, urinary sodium/creatinine ratio, and catecholamines were similar at each time point. Conclusions: The results suggest that irbesartan and estradiol, when used in combination, may cause a greater lowering of blood pressure in postmenopausal hypertensive women. This effect may be mediated via increased vasodilation and lower aldosterone levels. These results warrant further testing in larger clinical trials. Postmenopausal hypertensive women were treated with irbesartan, an angiotensin receptor blocker, with and without the addition of estradiol. A significantly larger number of women in the irbesartan and estradiol combination group had a reduction in both systolic and diastolic blood pressures compared with the irbesartan alone group, suggesting that estradiol may augment the antihypertensive effect of irbesartan.