MARS was a randomized, double-blind, placebo-controlled, angiographic trial comparing the effects of lipid lowering by lovastatin and diet with diet plus placebo in 270 subjects. The target study population consisted of males and females under 70 years of age with cholesterol levels from 200 to 295 mg/dL and coronary artery disease in two or more coronary artery segments. Follow-up coronary angiograms were performed two and four years post-randomization in 247 and 68 subjects, respectively; providing information on atherosclerosis regression/progression of coronary artery intrusive lesions. Carotid ultrasound images have been recorded at four month intervals for periods up to four years in 215 subjects providing information on atherosclerosis regression/progression of pre-intrusive (intima-media thickness) lesions in parallel with coronary artery intrusive lesions. Unique features of MARS included: 1) Simultaneous coronary angiography (evaluated both by quantitative coronary angiography (QCA) and panel-reading) and carotid ultrasonography in a cohort of over 200 subjects; 2) The opportunity to evaluate the largest lipoprotein and apolipoprotein data collected in an angiographic trial to date. This included extensive VLDL, LDL, IDL, and HDL subclasses as well as LDL type pattern, lipoprotein particles and apolipoprotein (including AI, B, CIII, and E); and, 3) The opportunity to evaluate dietary effects on atherosclerosis regression/progression only in one other angiographic trail, CLAS.