The purpose of this study was to analyze the size of the entire aorta at different anatomic levels in a large group of Chinese population with clinically evident arterial disease or cardiovascular risk factors to further explored the risk factors and potential alternative pathomechanisms for the development of aortic dilatation. Comprehensive transthoracic M-mode, 2-dimensional, and Doppler echocardiographic studies will be performed using commercially available equipment. The aortic dimensions were assessed at end-diastole at the different levels: (1) the annulus, (2) the mid-point of the sinuses of Valsalva, (3) the sinotubular junction, (4) the ascending aorta at the level of its largest diameter, (5) the transverse arch, (6) the descending aorta posterior to the left atrium, and (7) the abdominal aorta just distal to the origin of the renal arteries. The extension of dilation is defined as the number of dilated aortic segments. The relations among aortic dimensions and clinical characteristics will be assessed by multiple regression analysis. The current study was to determine the association of risk factors of CVD and atherosclerosis diseases with aortic dimension in Chinese patients with clinical event atherosclerotic disease or risk factors of atherosclerotic disease.