The Cholesterol Lowering Atherosclerosis Study (CLAS) was a coronary angiographic trial testing the efficacy of colestipol-niacin therapy in 188 nonsmoking, 40-59 year old men with previous coronary artery bypass graft surgery. Coronary artery atherosclerosis change was evaluated both by human consensus panel and by quantitative coronary angiography (QCA). In addition, B-mode ultrasounds of the common carotid artery was conducted every six months to provide measures of carotid IMT. Since the competion of the two-year CLAS study, subjects have been followed for up to 12 years. This long term follow-up of the CLAS cohort permits examination of the appropriateness of angiographic and ultrasound arterial endpoints as predictors of subsequent clinical coronary events. Angiographic and ultrasound (carotid IMT) endpoints also allow for testing of the associations between these various serial measures of atherosclerotic progression.