Conjugated estrogen administration improves common carotid artery elastic properties in normotensive postmenopausal women.
BACKGROUND
Various vascular effects of estrogens have been proposed to explain further the beneficial effect of replacement therapy in cardiovascular events.


OBJECTIVE
The study was undertaken to assess the effect of conjugated estrogen on the elastic properties of the large arteries in normotensive, healthy, postmenopausal women.


METHODS
Toward this end, we investigated the acute effect of conjugated estrogen on the elastic properties of the common carotid artery (CCA) in 20 normotensive, healthy, postmenopausal women (age 54+/-3 years) at baseline and 20 min after the intravenous administration of 1.25 mg conjugated estrogens. The CCA distensibility was derived by a combination of surface ultrasonographic data and simultaneous blood pressure measurements at the brachial artery. The carotid pulsatility index, a measure of brain impedance, was determined electronically by tracing the CCA Doppler waveform.


RESULTS
At baseline, CCA distensibility had a negative correlation with both patients' age and time since menopause (r = -0.57 and r = -0.48, p < 0.05 for both cases). After estrogen administration, estradiol and estrone plasma levels were restored to the range of usual premenopausal values. Estrogen induced a significant increase in CCA distensibility by 0.92+/-0.005 dyne(-1) x cm2 x 10(-6) (from 2.03 to 2.95 dyne(-1) x cm2 x 10(-6)) and a significant reduction in CCA pulsatility index by 0.24+/-0.06, (from 2.17 to 1.93) (p < 0.001 for both cases). The improvement in CCA distensibility had a negative correlation with both patients' age and time since menopause (r= -0.46 and r = -0.44, respectively, p < 0.05 for both cases).


CONCLUSIONS
Acute conjugated estrogen administration induced an improvement in CCA elasticity and a reduction in brain impedance in normotensive, postmenopausal women. As the age of women and the time since menopause increased, the improvement in carotid distensibility decreased in such selected subjects.
Kallikazaros
Ioannis
I
Department of Cardiology, Hippokration Hospital, University of Athens, Greece.
Tsioufis
Costas
C
Zambaras
Panagiotis
P
Stefanadis
Christodoulos
C
Toutouzas
Pavlos
P
D000375:Aging; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D004548:Elasticity; D015914:Estrogen Replacement Therapy; D004966:Estrogens, Conjugated (USP) / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology; D011673:Pulsatile Flow; D012044:Regression Analysis; D020521:Stroke / Q000517:prevention & control; D014463:Ultrasonography
D004966:Estrogens, Conjugated (USP)