Apolipoproteins and coronary artery disease.

In this study, we compared the relative utility of plasma levels of cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and apolipoproteins in identifying men with angiographically significant coronary artery disease in a combined sample of consecutive male patients undergoing coronary angiography (N = 304) and healthy, normal male control subjects (N = 135). The plasma apolipoprotein levels were measured by using specific radioimmunoassays. We found that plasma levels of apolipoprotein A-I, followed by those of apolipoproteins A-II and B, were better discriminators than plasma cholesterol, triglycerides, or HDL cholesterol levels for identifying those with coronary artery disease. In confirmation of previous findings, the presence of coronary artery disease resulted in lower levels of apolipoproteins A-I and A-II and HDL cholesterol and higher levels of apolipoprotein B, cholesterol, and triglycerides. Linear and quadratic discriminant function analysis demonstrated that by using the age of the patients and apolipoprotein A-I, A-II, and B levels, one could correctly classify patients either as being normal or as having angiographically significant coronary artery disease in more than 75% of the cases. Thus, plasma apolipoprotein levels (especially A-I and A-II) may be considerably better markers for coronary artery disease than traditional lipid determinations.