The clinical significance of small, dense low-density lipoproteins

Peak size of low-density lipoproteins (LDL) in humans does not show a normal, but a bimodal distribution and can be separated into two phenotypes, that differ in size, density, physicochemical composition, metabolic behavior, and atherogenicity. These phenotypes have been assigned as pattern A when larger, more buoyant LDL and pattern B when smaller, more dense LDL predominate. Small dense LDL correlates negatively with plasma HDL levels and positively with plasma triglyceride concentrations and is associated with the metabolic syndrome and increased risk for cardiovascular disease. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease (CHD). Recently the predominance of small dense LDL has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. In addition, several studies have suggested that therapeutic modulation of specific LDL subclasses may be of great benefit in reducing the atherosclerotic risk. Therefore, LDL size measurement may be of potential value in the clinical assessment and management of patients at high risk of CHD, a category that comprise individuals with both coronary and noncoronary forms of atherosclerosis. Screening for the presence of small dense LDL in such patients may potentially identify those with even higher vascular risk and may contribute in directing specific antiatherosclerotic treatments to prevent new vascular events in the same or another distric