Serum lipoproteins in patients with myocardial infarction.

The lipid and lipoprotein profile was examined in male patients with acute myocardial infarction (AMI) at the time of infarction (group A) and in male patients who had survived AMI 2-3 years before the study (group B), and compared to that of healthy controls. The myocardial infarction (MI) patients exhibited similar total cholesterol and LDL-cholesterol levels as the controls. However, the LDL mass concentration was higher in patients than in controls (P less than 0.01 for group A, P less than 0.001 for group B). In composition, patients' LDL in both groups was rich in protein and triglycerides but poor in cholesterol. The compositional changes in patient LDL were evident at all levels of LDL-cholesterol. The mean total HDL and HDL2 mass concentrations were lower in patients than in controls (P less than 0.001 for both groups), but there was no difference in HDL3 levels. Upon admission to hospital the patients with AMI at the time of examination (group A) had higher serum total triglyceride concentration than controls, but on the fasting morning samples serum triglyceride and VLDL lipid levels did not differ between patients and controls. Patients who had survived AMI 2-3 years prior to study (group B) exhibited higher serum total triglyceride and VLDL levels than the control subjects. On stepwise discriminant analysis, HDL2 protein concentration was the single best variable for distinguishing between patients and controls. The most powerful discriminatory parameter was the HDL/LDL protein ratio or the HDL2/LDL protein ratio.