Randomized, double-blind, placebo-controlled. Baseline arteriograms were performed and fasting lipid samples drawn before heparinization. Patients were stratified for age below 45 years, cigarette smoking within the previous month, and lipid patterns including familial hypercholesterolemia and triglyceride levels. Patients were given dietary counseling and randomly assigned to one of three treatments: lovastatin (20 mg twice a day) and colestipol (10 g three times a day); niacin (1 g four times a day) and colestipol (10 g three times a day): or conventional therapy with placebo (or colestipol if the LDL cholesterol level was elevated). The primary endpoint was a measure of change in the severity of disease in the proximal coronary arteries as measured by quantitative arteriography.