Active clinical trials for "Atherosclerosis"

Stroke is the first and the fourth leading cause of death in the United States and China, respectively. Disruption of cerebrovascular vulnerable atherosclerotic plaque is the major etiology of ischemic stroke. Therefore, early detection and treatment of vulnerable plaques occurring at the feeding arteries to brain (cerebral arteries) will be helpful for prevention of stroke. Atherosclerosis is a systemic disease that usually affects multiple vascular beds. Previous studies have shown that these high risk lesions in different segments of cerebral arteries (intracranial and extracranial arteries) might be racially specific. It is reported that, in stroke patients, intracranial vulnerable plaques are prevalent in Asian populations whereas atherosclerosis more frequently involves extracranial carotid arteries in American subjects. However, these findings are based on angiographic imaging approaches via measuring arterial luminal stenosis. Because the atherosclerotic plaque often appears as outward expansion, namely positive remodeling during progression, measuring luminal stenosis will underestimate the disease severity. Hence, directly viewing the plaque in the vessel wall is strongly suggested in order to objectively evaluate the cerebrovascular vulnerable plaque. High resolution, black-blood magnetic resonance (MR) imaging has been widely used to accurately characterize carotid vulnerable plaque in the last two decades. The aim of using MR black-blood techniques is to suppress the blood signal (black) to enhance the signal contrast between the vessel wall and blood in the arterial lumen. Excellent agreement has been achieved between MR imaging and histology in identification of plaque components, such as intraplaque hemorrhage and lipid core. For assessing carotid plaque, MR imaging is superior to computed tomography and ultrasound imaging techniques due to its advantages including noninvasive imaging, lack of ionizing radiation, excellent soft tissue resolution, and multi-parametric image acquisition. The Investigators hypothesize that there are specific characteristics in carotid vulnerable plaques in Chinese patients with ischemic cerebrovascular events such as ischemic stroke and transient ischemic attack (TIA). This study seeks to investigate the characteristics of vulnerable plaque in carotid arteries using high resolution, black-blood MR imaging in patients with recent TIA or ischemic stroke. This is a cross-sectional, multicenter study. A total of 1000 patients will be recruited from more than 10 different hospitals across China within 3 years. All patients will undergo MR imaging for brain and carotid arteries within two weeks after symptom onset. The prevalence of carotid vulnerable plaque and its correlations with brain ischemic lesions, traditional risk factors, and regional distribution of China will be determined.

Ischemic stroke is a leading cause of death and disability worldwide. Atherosclerosis, responsible for the 20% of ischemic strokes, is characterized by lipid accumulation in the artery wall that leads to chronic inflammation, cell proliferation and ultimately to vessel stenosis. One of the main features related to plaque progression and vulnerability is inflammation. Positron emission tomography with 18-fluorodeoxyglucos (18-FDG PET) allows an accurate quantification of plaque inflammation and it has been proved its usefulness in predicting early stroke recurrences. The investigators aim to test how modifiable vascular risk factors influence plaque inflammation assessed by 18-FDG PET. In addition, investigators will assess the association of this inflammation and circulating endothelial progenitor cells

A prospective, multicenter, cohort study to explore the stroke mechanisms of symptomatic intracranial atherosclerosis, the dynamic changes under aggressive medical treatment and their associations with clinical events using conventional MRI sequences plus high-resolution magnetic resonance (HR-MRI).

Objectives of Medical Research: Separation of LDL and HDL from blood samples of patients with high LDL and / or low HDL who have developed atherosclerotic disease with similar patients who have no evidence of atherosclerosis. Lipidomics and proteomics will examine whether there is a difference in lipid and protein composition and lipoprotein composition. If there are any changes in expression level or the composition of proteins or metabolites that make up lipoproteins, the investigator will try to figure out the mechanism responsible for these changes and their role in the metabolic process. the investigator will seek therapeutic measures through which these mechanisms can be inhibited and thus inhibit the development of sclerosis or even retraction.

The aim of this study is to establish a deep learning model to automatically detect the presence and scoring of carotid plaques in neck CTA images, and to determine whether this model is compatible with manual interpretations.

Part I: Survey of Coronary Artery Calcification and Stenosis in Participants with Different Glycaemic Status Aims: To evaluate coronary artery calcification and stenosis in community-dwelling adults with different glycaemic status, using dual-source CT angiography (CTA) Study Subjects and Methods: 200 adults with normal glucose regulation (NGR), 200 with impaired glucose regulation (IGR) and 200 with type 2 diabetes were recruited from an urban community of Shanghai, who then underwent a comprehensive examination including questionnaire, anthropometric measurements, biochemical analysis and CTA. Part II: Follow-up of Cardiovascular Events and Re-evaluation of Coronary Artery Calcification and Stenosis Aims and Methods: To investigate the development of cardiovascular diseases in subjects recruited in part I and re-evaluate coronary artery calcification and stenosis using CTA after 3-year follow-up To identify the predictive value of coronary artery calcification and stenosis with future risks of cardiovascular diseases and the possible development of coronary artery disorders among participants with different glycaemic status

Although it is frequently mentioned in the media that overweight and obesity have reached epidemic proportions worldwide and in this country, some Canadians are perplexed and sometimes confused about the role of obesity in diabetes and heart disease. In fact, the investigators even hear from time to time that there could be "healthy" obese individuals. In clinical practice, assessment of obesity as a risk factor for cardiovascular disease (CVD) remains a challenge as even some physicians are confused. However, studies conducted in our laboratory and by other research teams around the world over the last 20 years have clearly shown that body shape is more important than body size when evaluating the risk of overweight/obesity and that high accumulation of abdominal fat (excess belly fat) increases the risk of diabetes and cardiovascular disease (CVD). The investigators now need to better understand the link between excess belly fat and atherosclerosis (the thickening of artery walls by fatty deposits, also referred to as atherosclerotic plaque), leading to complications such as angina (chest pain) and myocardial infarction (heart attacks). Using non-invasive imaging techniques such as magnetic resonance imaging, the investigators therefore propose to examine the relationships between measures of fatness and of abdominal fat and the size of atherosclerotic plaque in large blood vessels of apparently healthy human subjects. This study is also a unique opportunity to look, for the first time, at the relationship between belly fat, blood sugar, several well-known risk factors for heart disease (cholesterol, blood pressure, cardiorespiratory fitness, etc.) and the size of atherosclerotic plaques. This research program should pave the way to the development of new improved preventive/therapeutic approaches focusing not on body weight but rather on abdominal fat and associated blood abnormalities which are predictive of the development of atherosclerotic plaques leading to the premature development of heart disease.

The purpose of this study is to investigate whether and what extent blood pressure variability is associated with arterial stiffness and carotid atherosclerosis, furthermore to compare the difference in the relationship of the types of blood pressure variability with arterial stiffness and carotid atherosclerosis.

CT of the abdomen is a very common examination performed for various indications.One of the common findings is vascular calcifications including calcifications of the renal arteries.Calcifications in the carotid arteries and coronary arteries are good predictor for obstructive atherosclerotic disease.Stenosis of the renal arteries can cause symptomatic or asymptomatic hypertension with subsequent clinical sequelae. Therefore early diagnosis of this condition is imperative. The goal of our study is to investigate the correlation between incidental calcifications of the renal arteries in CT examinations and the presence of actual stenosis of these vessels in patients with and without hypertension.

Atherosclerosis is unquestionably the leading cause of morbidity and mortality in developed countries, and the world-wide importance of acute vascular syndromes is increasing. Rupture of atherosclerotic plaque has been identified as the proximate event in the majority of cases of acute ischemic syndromes. Therefore, modalities capable of characterizing the atherosclerotic lesion may be helpful in understanding its natural history and detecting lesions with high risk for acute events. Optical coherence tomography (OCT) is a powerful tool capable of tomographic imaging based on low coherence interferometry. It is analogous to ultrasound imaging except that it uses infrared light instead of sound. Polarization-sensitive optical coherence tomography (PS-OCT) combines the advantages of OCT with additional image contrast of the sample. The added contrast is based on the ability of PS-OCT to detect the birefringent properties of a sample (phase retardation and fast-axis orientation) simultaneously. The goals of this project are: 1) to examine whether PS-OCT is an acceptable tool for the characterization of typical plaque constituents; and 2) to explain the correlation between birefringence and forming or rupture of a plaque; and 3) to establish a quantitative PS-OCT image criteria for atherosclerotic plaque characterization in vitro.