View clinical trials related to Arteriosclerosis.
Filter by:To examine whether the prevalence of subclinical coronary and aortic atherosclerotic disease is different among Japanese in Japan, Japanese in Hawaii, and black and white Americans.
This study will determine whether dietary nitrates and nitrites can produce nitric oxide in the body and dilate blood vessels in patients with coronary artery disease. Nitric oxide is normally made by endothelial cells that line blood vessels. It plays an important role in maintaining the normal function of arteries by keeping them open and preventing damage from substances such as cholesterol in the blood stream. Coronary artery disease is caused by atherosclerosis (hardening of the arteries or build-up of cholesterol and scar tissue within the walls of the arteries). Once arteries become clogged, the ability of the endothelium to produce nitric oxide diminishes considerably and may speed up the disease process, leading to shortness of breath, chest pain, and an increased risk of heart attack or stroke. Patients 21 years of age and older with coronary artery disease may be eligible for this study. Participants will have a medical history and physical examination, electrocardiogram (recording of the electrical activity of the heart), echocardiogram (ultrasound test of the heart), treadmill exercise stress test (see below), and will meet with a dietitian. They will be hospitalized at the NIH Clinical Center on two occasions. For 1 week before each admission, they will follow a diet prescribed by an NIH nutritionist. The diet before one admission will be high in nitrates and nitrites, and the diet before the other admission will be low in nitrates and nitrites. Each admission will last 4 days, during which participants will undergo the following tests: - Forearm blood flow study: Small tubes are placed in the artery and vein at the inside of the elbow of the dominant arm (right- or left-handed) and a small tube is placed in a vein of the other arm. The tubes are used for infusing saline (salt water) and for drawing blood samples. A pressure cuff is placed around the upper part of the dominant arm, and a rubber band device called a strain gauge is also placed around the arm to measure blood flow. When the cuff is inflated, blood flows into the arm, stretching the strain gauge at a rate proportional to the flow. Maximum grip-strength of the dominant arm is measured with a dynamometer. Forearm blood flow is measured and blood samples are drawn at the following times: 20 minutes after the tubes are placed; during a hand-grip exercise; and 4 minutes after the exercise is completed. - Brachial artery reactivity study: This test measures h...
To rescan 6,700 subjects in the MESA study to obtain computed tomography measures of calcification.
To evaluate common genetic variations, that in combination with exposure to tobacco smoke, may modify the risk of atherosclerosis.
To assess the associations of serum sex hormones with the presence and progression of subclinical atherosclerosis.
To determine the factors associated with progression of sub-clinical atherosclerosis and to evaluate the associations between the progression of sub-clinical atherosclerosis and the development of clinically manifest atherosclerosis.
To study the epidemiology of aortic calcium.
This study will look at the effect of a cardiac rehabilitation exercise program on release of stem cells from the bone marrow and on heart function. Stem cells are primitive cells produced and released by the bone marrow, circulate in the bloodstream and develop into white blood cells, red blood cells and platelets. Some stem cells may also develop into other kinds of cells, including those that make up heart muscle, especially if the heart has been damaged or is not getting sufficient blood. Stem cells called endothelial progenitor cells (EPCs) are thought to form new blood vessels that can carry blood to areas of the heart muscle that are oxygen-deprived because of clogged arteries. Previous experiments have shown that some EPCs can be forced out of the bone marrow by exercise. This study will examine whether repeated exercise and lifestyle changes increase the number of EPCs released into the bloodstream and if these cells improve heart and blood vessel function. Patients 21 years of age and older with coronary artery disease may be eligible for this study. Candidates will be screened with a medical history and physical examination, including a cardiovascular evaluation, and blood tests. The participants will be enrolled in a 2- to 3-month cardiac rehabilitation program that includes 24 to 36 60-minute sessions of exercise, plus instruction on lifestyle changes related to diet, stress management, and relaxation techniques. In addition, participants will undergo the following tests and procedures: - Brachial reactivity study: This test measures how well the arteries widen. The patients rest for 30 minutes, and then an ultrasound device is placed over the artery just above the elbow. The device measures the size of the artery and blood flow through it before and after the patient is given a spray of nitroglycerin under the tongue. - Blood tests for EPC levels and genetic testing: These measure EPCs and determine whether certain genes that may regulate EPC function are turned on or off. Genes are made up of DNA, the molecules that lead to the production of proteins by cells. Some of these proteins may be important in releasing EPCs from the bone marrow to travel in the bloodstream to the heart and repair blood vessels and muscle cells. - Treadmill exercise testing: Patients exercise on a treadmill with continuous monitoring of the heartbeat and frequent measurements of oxygen saturation, using a finger clip device. The patient continues to exercise until moderate chest pain, shortness of breath, or fatigue develops. - Questionnaire: Patients fill out a 15-minute questionnaire about their general physical and mental health status at the first and last visits to the clinic. - Magnetic resonance imaging (MRI) of the heart: Patients who are eligible to undergo MRI have this test twice during the study, once before beginning the rehabilitation program and again after completing the program. The MRI shows heart function and blood flow in the heart. For this test, the patient lies on a stretcher inside a long narrow cylinder (the scanner). During the scan, the drug dipyridamole, which increases blood flow to the heart, is infused into a vein of the hand or arm. Another drug, gadolinium, is also infused to brighten the images produced.
RATIONALE: - Atherothrombosis is a progressive and generalized vascular disease resulting in events leading to myocardial infarction (heart attack), stroke, and vascular death. - In patients at risk for this disease, it is characterized by an unpredictable, sudden disruption of atherosclerotic plaques, which may lead to total occlusion of artery due to formation of a clot. The use of aspirin (blood thinner agent) for reducing those major ischemic events is either indicated, or recommended by international guidelines. However, aspirin fails to prevent a high percentage of such life-threatening events. Therefore, more effective blood thinning therapy may provide additional clinical benefit to such patients. - The results of the CURE trial in patients with unstable angina demonstrate the additional benefit of long-term treatment (up to one year) with clopidogrel, (a blood thinner agent), when administered in combination with standard therapy including aspirin. The purpose of CHARISMA is to investigate whether a similar clinical benefit of clopidogrel may apply to a broad population of high-risk patients receiving low-dose aspirin therapy. Such population includes patients with previous cardiovascular, neurovascular or peripheral arterial manifestations of atherothrombosis and patients with combinations of recognized risk factors for atherosclerosis. OBJECTIVES: - To assess the efficacy of clopidogrel 75 mg once-daily by comparison with a placebo, in preventing cardiovascular morbidity/mortality. The study will compare the efficacy of the two regimens in preventing the occurrence of major cardiovascular complications (stroke, heart attack, cardiovascular death) in high-risk patients who are otherwise receiving low-dose aspirin therapy (75-162 mg daily). - To evaluate the safety of clopidogrel in this population, and more specifically the incidence of fatal or severe bleeding (as per GUSTO definition), in order to estimate the global benefit of clopidogrel in this patient population.
To examine the associations of common variation in inflammation/thrombosis genes with intermediate quantitative phenotypes and subclinical coronary atherosclerosis in the Coronary Artery Risk Factor Development in Young Adults (CARDIA) Study, a large, bi-racial cohort study.