Quantitative Coronary Angiography to Measure Progression andRegression ofCoronary Atherosclerosis Value, Limitations, andImplications forClinical Trials

T herehavebeenfive primary prevention trials ofwhichthepurpose wastodetermine whetherreducing hypercholesterolemia wouldalso decrease theincidence ofcoronary heart disease (CHD).1-5 Twoweredietary studies, and three werepharmacological studies. Although there wereinconsistencies inthefindings amongthetrials, largely duetodifferences indesign andmethodof intervention, eachdemonstrated significant reduc- tionintheincidence ofCHD,particularly CHD morbidity, although noneshowed aconvincing reduc- tion intotal mortality. However, there isevidence to suggest that asynergistic effect occurs wheninterven- tions arecombined, especially whenoneintervention isaimedatreducing hypercholesterolemia. Forin-