Clinical trials have provided increasing evidence of the value of lipid lowering in preventing clinical coronary events. With the advent of more potent lipid-regulating agents, a greater degree of cholesterol lowering--particularly of cholesterol carried in low density lipoproteins--is now possible. Trials monitored by angiography or ultrasound have demonstrated slowed progression and even regression of atherosclerotic lesions in subjects in whom lipid lowering was accomplished by diet and other lifestyle modifications, drugs, and/or partial ileal bypass surgery, but the changes measured in the vessel lumen or wall are often modest compared with the reduction in clinical events, suggesting that clinical benefit may be derived from mechanisms other than the absolute decrease in lesion size. Possible mechanisms include lesion stabilization, improved endothelial function, increased vascular reactivity, and decreased inflammatory response. The identification of risk factors besides elevated blood cholesterol level, such as lipoprotein oxidation, blood triglyceride level and insulin resistance, may provide additional targets for intervention.
