Randomized, double-blind, factorial design. In this multicenter study, patients were assigned to one of four drug combination groups: active lovastatin/active warfarin, active lovastatin/warfarin placebo, lovastatin placebo/active warfarin, and lovastatin placebo/warfarin placebo. Daily aspirin was recommended for everyone. Ultrasound was performed for screening, at baseline and semiannually thereafter. Lipid profiles were obtained at screening, at baseline, monthly for the first three months, at six months, and annually thereafter, with beta quantification at baseline. Recruitment began in the tenth month of the trial and continued for one year, ending in September 1990. Treatment continued through the 51st month. Average treatment period was 2.7 years. Subjects were offered a dietary regimen for three months prior to receiving any drug therapy. Only those individuals whose lipid levels did not fall below a certain point continued in dietary intervention. The primary outcome measure was the three year change in mean maximum intimal-medial thickness (IMT) in twelve walls of the carotid arteries. Secondary outcomes included change in single maximum IMT and incidence of major cardiovascular events.