View clinical trials related to Atherosclerosis.
Filter by:To conduct a multicenter study of the relationship between insulin resistance and cardiovascular disease (CVD) and its risk factors in a tri-ethnic (African-American, Hispanic, and non-Hispanic white) population aged 40 to 69 years at baseline. Also, to identify the genetic determinants of insulin resistance and visceral adiposity.
To determine morbidity and mortality from cardiovascular disease among American Indians and to compare cardiovascular disease risk factor levels among Indian groups living in different geographic areas.
To measure associations of established and suspected coronary heart disease risk factors with both atherosclerosis and new coronary heart disease events in representative cohorts from four diverse United States communities. To compare the communities with respect to risk factors, medical care, atherosclerosis, and coronary heart disease incidence. ARIC has two components in each community: study of representative cohorts of adult men and women, and community surveillance of morbidity and mortality.
To conduct epidemiologic surveys of the distribution, causes, and consequences of the dyslipoproteinemias. The Population Studies include the Prevalence Study, the Family Study, and the Mortality Follow-up Study and shared the same general population base.
The Framingham Heart Study was initiated to study the factors associated with the development of cardiovascular disease by employing long-term surveillance of an adult population in Framingham, Massachusetts. The Framingham Offspring Study was initiated to assess familial and genetic factors as determinants of coronary heart disease.
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.
This study will examine the use of magnetic resonance imaging (MRI) in detecting blood vessel inflammation. The results of this study may later be applied to diagnosing inflammation of arteries in patients with atherosclerosis, predicting disease progression in these patients, and guiding therapy. Patients with peripheral artery disease (for example, blockage of a leg artery) undergoing balloon angioplasty at Suburban Hospital in Bethesda, Maryland, may be eligible to participate in this study. Because this procedure, which opens blocked arteries, can cause inflammation in the vessel wall, it affords an opportunity for studying MRI detection of such inflammation. Study candidates will be screened with a medical history and physical examination. Participants will have a MRI scan and blood drawn at Suburban Hospital before the angioplasty and again either 1 to 3 days or 2 weeks after the procedure. Before the MRI scan is begun, a catheter (a thin plastic tube) is inserted in an arm vein and 90 milliliters (about 3 ounces) of blood is drawn. The patient then lies on a table that slides into the MRI scanner-a large donut-shaped machine with a magnetic field. A flexible, padded sensor called an MRI coil is placed over the area to be imaged; this device is used to improve the quality of the pictures. During the scan a contrast material called gadolinium is injected through the catheter. Gadolinium brightens the image of the blood vessels. The procedure lasts up to 2 hours.
This study will evaluate ways to improve magnetic resonance angiography (MRA) for diagnosing atherosclerosis (hardening and narrowing of the arteries). MRA is a new method for looking at arteries and veins without standard angiography, which requires inserting a catheter into a blood vessel, injecting a contrast material, and obtaining X-ray images. Current MRA techniques, however, do not depict the lumen (cavity) of small vessels well enough to accurately determine the extent of their narrowing. This study will test image processing methods with the eventual goal of improving MRA accuracy to the point that it can replace X-ray catheter angiography for diagnosing atherosclerotic disease. Patients with atherosclerosis who have had conventional angiography at Suburban Hospital in Bethesda, MD, may be considered for this study. They will be screened with a brief history and physical examination, and those enrolled will have a MRA scan within 72 hours of their conventional angiogram. For this procedure, a catheter is placed in a vein in the patient's arm and the patient lies on a table that slides into a magnetic resonance imaging (MRI) scanner-a large donut-shaped machine with a magnetic field. Surface coils-flexible, padded antennae used to improve the quality of the pictures-are wrapped around the patient's legs. At times during the scan, the patient is asked to hold his or her breath for several seconds, and a contrast material called gadolinium is injected through the catheter in the vein. This substance enhances the images of blood flow in the vessels. The procedure generally takes about an hour and a half, although the actual imaging takes only a small part of that time.
This minimal risk protocol is designed to assess the reproducibility of B-mode ultrasound measurements of carotid intima media thickness (IMT) when the scans are performed in CC Radiology and read using a computerized edge reader. Up to 20 volunteers will have two ultrasounds performed within a 6-month period. IMT thickness is used as a surrogate marker for atherosclerosis and may be of value in clinical trials.
Hardening of the arteries (atherosclerosis) and heart disease are much more common in men than in women. However, as women grow older, especially after menopause the incidence of atherosclerosis and heart disease increases. These findings suggest that estrogen may be protective and help in preventing heart disease. Studies of large groups of post-menopausal women suggest that hormone replacement therapy (therapy that includes estrogen) reduces the risk of heart disease. Estrogen causes favorable changes in particles that carry cholesterol in the blood stream and improves function of blood vessels. Estrogen may also stimulate the immune system's ability to fight off infections that may lead to or contribute to atherosclerosis. Researchers believe two specific infectious agents (Chlamydia pneumoniae and human cytomegalovirus) may cause damage to the lining of blood vessels resulting in inflammation and the development of atherosclerosis. The purpose of this study is to determine if estrogen treatment can change how the immune system responds to chronic infections, by Chlamydia pneumoniae and human cytomegalovirus, in postmenopausal women.