The significance of low-density-lipoproteins size in vascular diseases

Low density lipoproteins (LDL) comprise in humans two different main fractions: large, buoyant and small, dense particles. Small, dense LDL particles correlate negatively with plasma HDL levels and positively with plasma triglyceride concentrations and are 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). 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 comprises individuals with non-coronary forms of atherosclerosis: peripheral arterial disease, carotid artery disease, abdominal aortic aneurysm. Potentially, screening for the presence of small, dense LDL in patients with those clinical forms of atherosclerosis may identify those with even higher vascular risk and may contribute in directing specific anti-atherosclerotic treatments in order to prevent new vascular events in the same or another district. However, to-date, not so many studies have investigated the LDL size in patients with non-coronary forms of atherosclerosis and we need to wait for further contributions with larger number of patients, even if available data seem to suggest an association between small, dense LDL and such diseases. The predominance of small dense LDL particles has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III but screening for the presence of small, dense LDL particles in patients with non-coronary forms of atherosclerosis has not been so far recommended.