 Two conceptual advances occurring in the 1980s made it possible to test the hypothesis that significant alterations in serum lipoproteins can substantially reduce atherosclerosis progression or even induce regression. The first advance was in the development of arteriograms used in characterizing atherosclerosis, greatly reducing the number of patients required for the evaluation of an intervention designed to prevent coronary atherosclerosis progression. The second advance was the development of lovastatin that provides a lipid-lowering alternative much easier to tolerate than the niacincolestipol combination previously used, and has been shown to be comparably effective for LDL reduction in patients with a family history of high cholesterol. 