Plasma Lipids and Apolipoproteins as Risk Factor of Ischemic Heart Disease

ABSTRACT

Recent studies suggest that apolipoproteins may be better predictor of ischemic heart disease than are plasma lipids, such as total cholesterol and high density lipoprotein cholesterol(HDL-C). To examine this hypothesis, plasma levels of major lipids and major apolipo-proteins were measured and their derivatives were calculated in 30 male patients with ischemic heart disease(16 angina pectoris and 14 old myocardial infarction) and 30 age-matched male healthy controls. Plasma levels of lipids were obtained by conventional methods and apolipoproteins by Rocket immunoelectrophoresis. Levels of HDL-C, HDL2-cholesterol(HDL2-C), and apolipoprotein-AII, and ratios of HDL-C/total cholesterol, HDL2-C/total cholesterol, and apolipoprotein-AI/apolipoprotein-B were lower in the group of patients than in controls. Levels of low density lipoprotein cholesterol(LDL-C) and apolipoprotein-B, and ratios of lDL-C/HDL-C and apolipoprotein-AI/apolipoprotein-AII were higher in the group of patients. There were no statistically significant differences in the levels of total cholesterol and apolipoprotein-AI between the two groups. Stepwise discriminators analysis showed that apolipoprotein-B and apolipoprotein-AII were better discriminators than plasma lipids for identifying those with ischemic heart disease. One could correctly classify 78% of the cases by using the levels of the two apolipoproteins. By using the level of apolipoprotein-B, one could correctly classify 73% of the cases. There were no correlations between the levels of total cholesterol and HDL-C in the controls whereas there were positive correlations between the levels in the group of patients. In conclusion, this study showed that apolipoprotein-B was the best single discriminator for identifying the patients with ischemic heart disease, followed by apolipoprotein-AII.