Effects of Hormone Replacement Therapy on Inflammation and Stiffening of Artery Walls
Status:
Completed
Trial end date:
2002-01-01
Target enrollment:
Participant gender:
Summary
This study will determine the effects of hormone replacement therapy (estrogen alone or
estrogen and progesterone) on the walls of arteries in postmenopausal women. Inflammation and
stiffness of artery walls are two risk factors for atherosclerosis-deposits of fatty
substances (plaques) that can block the vessel, causing a heart attack or stroke. Estrogen
raises the levels of certain substances in the blood that cause vessel inflammation and
lowers the levels of others. This study will measure the net effects of estrogen on artery
wall inflammation and stiffness.
Postmenopausal women in good health may participate in this study. Volunteers will be
screened for eligibility with a complete medical history, heart examination, and blood tests.
Participants will be randomly assigned to receive either: 1) hormone therapy (estradiol 2 mg
daily alone for women who have had a hysterectomy or estradiol plus micronized progesterone
200 mg daily for women with an intact uterus); or 2) placebo (look-alike pills that contain
no active drug). Women in both groups will take pills for 3 months, then no pills for 1
month, and then will crossover to the alternate therapy for 3 months (i.e., those in the
original placebo group will take hormones, and those in the hormone group will take placebo).
At the end of each 3-month treatment period, participants will undergo the following
procedures to assess blood vessel inflammation and stiffness:
1. Blood tests - 60 cc (about 2 ounces) of blood will be drawn to measure levels of
hormones, cholesterol, and substances in the blood that indicate inflammation of the
vessels.
2. Ultrasonography - an ultrasound probe will be applied gently on the neck to image the
right and left carotid arteries (arteries in the neck that lead to the brain). During
the procedure, the heart's electrical activity will also be monitored with an
electrocardiogram and a blood pressure cuff will be wrapped around the arm to obtain
blood pressure measurements every 5 minutes.
3. Magnetic resonance imaging (MRI) - Images of the carotid arteries are taken while the
volunteer lies on a table in a narrow cylinder containing a magnetic field. A padded
sensor called an MRI coil is placed over the neck and earplugs are placed in the ears to
muffle the loud noise of the machine during scanning. During the second half of the
exam, gadolinium is injected through a catheter (thin, flexible tube) inserted into a
vein. Gadolinium is a contrast agent that is used to brighten the scan images.
Information from this study will increase knowledge about the effects of estrogen on vessel
wall inflammation. As such, it may be used in the future to help guide decisions about
chronic hormone replacement therapy in postmenopausal women.