The Use of Carotid Artery Ultrasound for the Assessment of Coronary Artery Disease and Cardiovascular Risk
Background: It is well known that the majority of cardiovascular (CV) events are caused by atherosclerotic plaque. However, it has recently been shown that it is not the quantity of plaque, but rather its vulnerability to rupture that increases cardiovascular risk. Coronary angiography remains the clinical standard for the diagnosis of coronary artery disease (CAD), or atherosclerosis of the coronary arteries, though it is not recommended for initial screening. Thus, the development of safe, effective and accessible screening tools for CAD is essential. It has been previously shown that quantifying plaque in the carotid artery serves as a prediction method of significant CAD. Thus, the central theme of this PhD project was to evaluate the correlation between carotid plaque characteristics, significant angiographic CAD, and CV outcomes. Methods: In a cohort of intermediate risk patients referred for coronary angiography, basic and advanced ultrasound modalities were carried out in order to assess both plaque quantity and features that contribute to plaque vulnerability. Results: We demonstrated that hand-held and conventional ultrasound devices could equally quantify carotid plaque. Beyond quantification, we showed that the vulnerability characteristics of neovascularization and ulceration were able to independently predict CAD and 30-day cardiovascular outcomes. Moreover, we demonstrated for the first time that there is a direct link between intraplaque neovascularization and plaque composition in the carotid plaque lesions of patients with acute coronary syndrome. Conclusions: Overall, the data presented in this thesis support the use of carotid plaque characteristics detected using novel ultrasound methods as imaging biomarkers for cardiovascular risk.