Background3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors are widely prescribed for hyperlipidemia, yet their effect on the evolution of coronary atherosclerosis has not been defined.Methods and ResultsTo address this issue, 331 patients with diffuse but not necessarily severe coronary atherosclerosis documented on a recent arteriogram and with fasting serum cholesterol between 220 and 300 mg/dL were enrolled in a randomized, double-blind, placebo-controlled trial. All patients received intensive dietary counseling. Lovastatin or placebo was begun at 20 mg/d and was titrated to 40 and 80 mg during the first 16 weeks to attain a fasting low-density lipoprotein (LDL) cholesterol ≤130 mg/dL. The mean lovastatin dose was 36 mg/d. Coronary arteriography was repeated after 2 years. In 299 patients (90%), 3858 coronary segments containing 2309 stenoses were measured blindly on pairs of films with an automated computerized quantitative system. Total and LDL cholesterol decreased by 21±11% and 29±11%, respectively, in the lovastatin-treated group but changed by <2% in placebo patients. The primary end point, coronary change score, defined as the per-patient mean of the minimum lumen diameter changes (follow-up minus baseline angiogram) for all lesions measured, excluding those <25% on both films, worsened by 0.09±0.16 mm in the placebo group and by 0.05±0.13 mm in the lovastatin group (P= .01). Progression (a worsening in minimum diameter of one or more stenoses by.0.4 mm) with no regression at other sites occurred in 48 of 146 lovastatin and 76 of 153 placebo patients (33% versus 50%,P= .003). New coronary lesions developed in 23 lovastatin and 49 placebo patients (P= .001). The beneficial effect of treatment was most pronounced in the more numerous, milder lesions and in patients whose baseline total or LDL cholesterol levels were above the group median.ConclusionsLovastatin slows the progression of coronary atherosclerosis and inhibits the development of new coronary lesions.