Clinical significance of lipoprotein size and risk for coronary atherosclerosis.

Correlation between coronary heart disease and lipoprotein size and composition is well documented. Within the low-density lipoprotein (LDL) family the small LDL particles are associated with increased risk of coronary heart disease. These particles also have increased apolipoprotein (apo) B content. The appearance of these small LDL particles is the manifestation of complex alteration of plasma lipoprotein metabolism. The LDL size is influenced by genetic, endocrine, and environmental factors. Within the high-density lipoprotein (HDL) family the decrease of larger HDL2 particles is associated with coronary heart disease. HDLs can also be separated according to their apoprotein composition into particles containing lipoprotein (Lp)A-I only and particles containing LpA-I and LpA-II. Most studies have shown that the concentration of LpA-I-only particles decreases in coronary heart disease. HDLs are remodeled in the circulation and this remodeling continues in vitro after the blood is taken. Therefore adequate preservation of blood samples is necessary.