View clinical trials related to Atherosclerosis.
Filter by:Magnetic Resonance Angiography (MRA) is a method used to evaluate arteries and veins without the use of invasive catheters or x-rays (radiation). MRA technique has been continuously improving and has become more accurate at diagnosing problems of narrowing in blood vessels. However, MRA has a difficult time detecting narrowing in small blood vessels, limiting its use to large arteries. The purpose of this study is to recruit patients diagnosed with or suspected of having, atherosclerosis (hardening of the arteries) to participate in a series of new state-of-the-art diagnostic tests using MRA. This study is a combined effort between the National Institutes of Health (NIH), Uniformed Services University of the Health Sciences (USUHS), and General Electric Medical Services and is supported a Cooperative Research Agreement is to (CRADA). The goal of this study is to improve MRA to the point that it can reliably replace diagnostic x-ray catheter angiography in the evaluation of patients with atherosclerosis.
Black Americans tend to die more often from and have more diseases associated with heart disease than White Americans. The exact cause of this is unknown, but it is likely a combination of genetics, behavior, risk factors, strategies for education and prevention, and socioeconomic factors. Recent studies have suggested that faster biological processes in blood vessels of Black Americans may be the cause of increased amounts of heart disease. In addition, small blood vessels in Black Americans seem to be less responsive to substances that relax blood vessels, which may explain increased blood pressure levels. In this study researchers plan to study artery relaxation (dilation) in response substances affecting the cells lining blood vessels (endothelin). Researchers will compare the results of this study in black and white people to find out whether racial differences may contribute to increases in heart disease and heart related deaths in blacks.
The renin angiotensin system (RAS) plays an important physiological and pathophysiological role in the control of blood pressure and plasma volume. Inhibition of the RAS is useful in the treatment of hypertension, cardiac failure and in some patients with myocardial infarction. Several recent clinical trials with angiotensin converting enzyme inhibitors (ACEI) have shown that they also reduce the incidence of myocardial infarction, but the mechanisms underlying this anti-ischemic effect are poorly understood. ACEI reduce angiotensin II synthesis and prevent bradykinin degradation. Results from ongoing studies in the Cardiology Branch (Protocol 95-H-0099) designed to investigate the link between ACEI and the vascular endothelium indicate that ACEI improve both endothelial dysfunction and metabolic coronary vasodilation, an effect that is partially mediated by bradykinin. The current protocol is designed to investigate whether the beneficial effects of ACEI on endothelial function are also partly due to inhibition of angiotensin II. The recent development of selective angiotensin II type 1 (AT1) receptor antagonists allows us to specifically examine the effects of angiotensin II on vasomotor activity.
The renin angiotensin system (RAS) plays an important physiological and pathophysiological role in the control of blood pressure and plasma volume. Inhibition of the RAS is useful in the treatment of hypertension, cardiac failure and in some patients with myocardial infarction. Several recent clinical trials with angiotensin converting enzyme inhibitors (ACEI) have shown that they also reduce the incidence of myocardial infarction, but the mechanisms underlying this anti-ischemic effect are poorly understood. ACEI reduce angiotensin II synthesis and prevent bradykinin degradation. Results from ongoing studies in the Cardiology Branch (Protocol 95-H-0099) designed to investigate the link between ACEI and the vascular endothelium indicate that ACEI improve peripheral endothelial function, an effect that is partially mediated by bradykinin. The current protocol is designed to investigate whether the beneficial effects of ACEI on peripheral endothelial function are also due to inhibition of angiotensin II. The recent development of selective angiotensin II type 1 (AT1) receptor antagonists allows us to specifically examine the effects of angiotensin II on vasomotor activity.
Iron has been proposed to contribute to atherogenesis in humans by facilitating the oxidation of lipoproteins. This observational study will evaluate the association between frequency of blood donation - expected to be associated with relatively reduced body iron stores in frequent donors - and carotid atherosclerosis. The primary outcome variable will be whether the presence and extent of asymptomatic carotid atherosclerosis as measured by ultrasound is greater in infrequent (less than or equal to 1 donations/year greater than or equal to 5 years) vs. frequent (greater than or equal to 4 donations/year greater than or equal to 5 years) blood donors. Body iron stores, lipid and hemostatic parameters, nitric oxide formation, inflammatory parameters, and markers of vascular oxidative stress will be analyzed as secondary outcome measures. Laboratory analysis and ultrasound testing will be performed blinded to the patient's phlebotomy and iron status. Sixty frequent (n=40 males greater than 40 y/o, n=20 females greater than 50 y/o) and 60 infrequent (n=40 males greater than 40 y/o, n=20 females greater than 50 y/o) blood donors will be recruited for this study from the Department of Transfusion Medicine, W. G. Magnuson Clinical Center. All donors will be assessed for study eligibility and cardiovascular risks during the screening visit. The presence of atherosclerotic lesions by carotid ultrasound and secondary outcome parameters will be assessed during a second visit.
The purpose of this study is to investigate whether the susceptibility of subjects to atherosclerosis is influenced by prior CMV exposure, whether the susceptability to endothelial dysfunction in patients with and in patients without atherosclerosis is influenced by prior CMV exposure.
The walls of blood vessels are lined by flat cells that are responsible for releasing substance(s) that control the activity of the blood vessel. These cells are referred to as the endothelium of the blood vessel. One of the substances released from the endothelium is called nitric oxide (NO). This substance functions to keep blood vessels relaxed and to prevent blood from clotting inside the vessels. Studies done by researchers in the Cardiology Branch of the National Heart, Lung and Blood Institute have shown that nitric oxide activity may be lower in patients with hardening of the arteries (atherosclerosis) and risk factors for atherosclerosis. Another substance released by the cells of the endothelium is called bradykinin. It functions to stimulate the production of nitric oxide. Therefore bradykinin is also responsible for the relaxation and widening of blood vessels. An enzyme found in the blood called angiotensin-converting enzyme (ACE) inactivates baradykinin and thereby decreases the production of nitric oxide. The activity of ACE is determined by genetics and is different in each person. Medications that block ACE (ACE-inhibitors) may be useful for patients with high levels of ACE activity. This study is designed to determine; 1. The role of bradkinin in stimulating the production of nitric oxide 2. Whether ACE-inhibitors improve blood vessel relaxation caused by bradykinin 3. Whether ACE-inhibitors improve abnormal blood vessel relaxation 4. Whether ACE-inhibitors and bradykinin affect blood clotting 5. Whether blood vessel response to ACE-inhibitor and bradykinin depends on the patients genetic make-up
Early studies have shown that the immune system may play a role in the development of strokes. Conditions such as high blood pressure, high cholesterol, diabetes, and old age can activate the immune system and increase the risk of developing hardening of the arteries (atherosclerosis) and damaged blood vessels. Researchers will attempt to characterize factors that may contribute to atherosclerosis and stroke by measuring certain components of the immune system, cytokines and leukocyte activation. Measurements will be taken from patients that are considered to be stroke prone and from patients without risk factors for the development of stroke. Researchers will measure the immune system components at the beginning of the study, at six months, and at the one-year completion of the study. The study will attempt to determine; I) If patients with risk factors for stroke have an increased activation of the immune system II) If patients with risk factors for stroke that are symptomatic have higher levels of immune system activation compared to patients who do not have symptoms III) If patients with increased activation of the immune system have accelerated hardening of the arteries (atherosclerosis)
The purpose of this study is to prevent major cardiovascular events (heart attack, stroke, or cardiovascular death) in adults with type 2 diabetes mellitus using intensive glycemic control, intensive blood pressure control, and multiple lipid management.
To determine whether combined therapy with the lipid lowering agents colestipol hydrochloride plus niacin would produce significant change in coronary, carotid, and femoral artery atherosclerosis and coronary bypass graft lesions as determined by angiography. Also, to determine possible correlations between lesion changes and plasma lipid and lipoprotein cholesterol levels and to explore interrelationships of atherosclerosis change in femoral, coronary, and carotid arteries.