Rui Hu
Published: 2017-01-27
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This dissertation, "Applications of Non-invasive Vascular Imaging Techniques in Cardiovascular Risk Assessment and Management" by Rui, Hu, 胡瑞, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled Applications of Non-Invasive Vascular Imaging Techniques in Cardiovascular Risk Assessment and Management Submitted by Hu Rui for the Degree of Master of Philosophy at the University of Hong Kong in June, 2006 Non-invasive imaging techniques to detect atherosclerosis have emerged as useful tools for assessing the risk of cardiovascular diseases and surrogate endpoints for monitoring cardiovascular risk interventions. This thesis presents the results of two cross-sectional studies and one interventional study of the applications of vascular ultrasound and ophthalmoscope in assessing structure or function in macrovasculature and microvasculature. In the first cross-sectional study, the relative importance of diagnostic and prognostic values of non-invasive ultrasound assessment of carotid intima-media thickness (IMT) and brachial flow-mediated vasodilatation (FMD) were evaluated in 298 consecutive high-risk Chinese patients admitted for coronary angiography due to chest discomfort. The mean maximum of IMT (mmIMT), but not FMD, was found to be an independent predictor for the presence of the significant coronary artery disease (CAD) of >50% stenosis, and it closely correlated with the extent of CAD as assessed by Gensini angiographic score. During a median follow up of 16 months, 36 patients (12.8%) experienced spontaneous cardiovascular events (cardiovascular death, acute myocardial infarction, unstable angina pectoris and congestive heart failure). The impaired brachial FMD rather than the increased carotid mmIMT independently predicted the occurrence of spontaneous cardiovascular events. In patients without significant CAD, women were more likely than men to develop cardiovascular events. Therefore, endothelial function test of the brachial artery to measure FMD could be a useful tool to identify patients at risk of cardiovascular IIevents for intensive risk factor modification and vigilant follow up, especially in women without significant CAD. Moreover, impaired nitrate-mediated vasodilatation (NMD) was found to be a marker that could reflect the status of nitrate tolerance. Recent studies suggested that arteriolar retinopathy reflected systemic microvascular disease and was associated with increased risk of cardiovascular events. In the second cross-sectional study, the relationship between cardiovascular risk factors and arteriolar retinopathy as assessed by ophthalmoscope was investigated in 243 apparently healthy Chinese subjects during routine health checks. In this study, aging, hypertension, smoking and being overweight were identified as important risk factors for the presence of arteriolar retinopathy. Smoking was also associated with an increase of homocysteine in subjects with grade II retinopathy. However, smoking rather than hyperhomocysteinemia was found to be an independent predictor for the progression of arteriolar retinopathy. Finally, the short-term effect of aggressive cardiovascular risk factor modifications on endothelial function was studied in 25 CAD patients with concomitant hypertension and hypercholesterolemia. After 14 weeks of intensified blood pressure and lipid control with a combination with a calcium channel blocker and statin, there was a significant improvement in endothelial function. This finding provides further evidence to support aggressive risk factor modificat