Estrogen improves endothelium-dependent, flow-mediated vasodilation in postmenopausal women.
OBJECTIVE
To assess the effect of estrogen replacement therapy on endothelium-dependent vasodilation in postmenopausal women.


METHODS
Double-blind, placebo-controlled, crossover trial.


METHODS
University medical center.


METHODS
13 postmenopausal women aged 44 to 69 years (average age, 55 +/- 7 years).


METHODS
Patients were randomly assigned to receive placebo, oral estradiol at a dose of 1 mg/d, and oral estradiol at a dose of 2 mg/d. Each treatment phase lasted 9 weeks.


METHODS
High-resolution ultrasonography was used to measure vascular reactivity in a peripheral conduit vessel, the brachial artery. Endothelium-dependent vasodilation was determined by measuring the change in brachial artery diameter during increases in flow induced by reactive hyperemia. Endothelium-independent vasodilation was measured after sublingual nitroglycerin was administered.


RESULTS
Flow-mediated, endothelium-dependent vasodilation of the brachial artery was greater when patients received estradiol (13.5% and 11.6% for 1-mg and 2-mg doses, respectively) than when patients received placebo (6.8%; P < 0.05 for each dose compared with placebo). In contrast, estrogen administration had no effect on endothelium-independent vasodilation as assessed by sublingual nitroglycerin.


CONCLUSIONS
Short-term estrogen replacement therapy improves flow-mediated endothelium-dependent vasodilation in postmenopausal women. This improvement may be mediated by a direct effect of estrogen on vascular function or may be induced through modification of lipoprotein metabolism.
Brigham and Women's Hospital, Boston, Massachusetts.
E H
EH
Lieberman
M D
MD
Gerhard
A
A
Uehata
B W
BW
Walsh
A P
AP
Selwyn
P
P
Ganz
A C
AC
Yeung
M A
MA
Creager
D000284:Administration, Oral; D000328:Adult; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000187:drug effects; D002784:Cholesterol / Q000097:blood; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008593:Menopause / Q000097:blood / Q000502:physiology*; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage; D014463:Ultrasonography; D014664:Vasodilation / Q000187:drug effects*
D004958:Estradiol; D002784:Cholesterol; D005996:Nitroglycerin