Elevated Lipoprotein(a) Concentration and Presence of Subfractions of Small Dense Low Density Lipoproteins as Independent Factors of Risk of Ischemic Heart Disease

Aim. To study relation of lipoproteina - Lp(a) and subfractional composition of apoB containing lipoproteins to the presence of ischemic heart disease (IHD). Manerial and methods. Parameters of lipid spectrum, Lp(a), and subfractions of apoB containing lipoproteins were determined in blood serum of 187 patients with known data of instrumental examination. Results. Lp(a) concentration was not linked to any of risk factors, levels total cholesterol (TC), low and high density lipoprotein CH, and subfractions of lipoproteins. In total group triglyceride (TGG) level correlated with content of small dense LDL (sdLDL) (r=0.445, p<0.0001) and mean dimension of LDL particles (r=-0.424, p<0.0001). This correlation was absent in the subgroup with Lp(a) >= 30 mg/dl and was strengthered among patients with normal Lp(a) level. In total group presence of IHD was associated with sex (r=0.325, p<0.0001), Lp(a) concentration (r=0.271, p=0.0001), and level of triglycerides.(r=0.159, p=0.030). In multiple regression analysis levels of TG, Lp(a) and sdLDL were selected as factors independently associated with presence of IHD. Detection of subfractions sdLDL >2 mg/dl in blood plasma (atherogenic profile B), as well as lowering of concentration of large LDL subfractions significantly increased probability of IHD presence in patients with elevated Lp(a) concentration Lp(a) concentration. Conclusion. Lp(a) is an independent factor of risk of coronary atherosclerosis more significant than shifts in subfractional composition of apoB containing lipoproteins. In patients with Lp(a) concentration <= 30 mg/dl subfractions of sdLDL were directly related to TG. Level of sdLDL and large lipoproteins of intermediate density are directly related to the presence of IHD. Large LDL correlates with concentration of HDL DL C and probably is cardioprotective. sdLDL content >2 mg/l or hypertriglyceridemia (TG > 1.7 mmol/l) significantly increase chances of detection of confirmed IHD in patients with elevated Lp(a).