RELATION OF PLASMA-LEVELS AND COMPOSITION OF APOLIPOPROTEIN-B CONTAINING LIPOPROTEINS TO ANGIOGRAPHICALLY DEFINED CORONARY-ARTERY DISEASE IN YOUNG-PATIENTS WITH MYOCARDIAL-INFARCTION

Background. Hypertriglyceridemia is a common metabolic disturbance in men <45 years old with myocardial infarction. To further investigate t he relation between triglyceride-rich lipoproteins and severity of cor onary atherosclerosis in this subset of postinfarction patients, apoli poprotein B-containing lipoproteins of 64 consecutive patients were su bfractionated in connection with coronary angiography. Methods and Res ults. Density-gradient ultracentrifugation of plasma and coronary angi ography were performed 4 to 6 months after the myocardial infarction. Global coronary atherosclerosis and the number and severity of distinc t stenoses were evaluated by semiquantitative analysis of 15 proximal coronary segments. The majority of the patients (60%) were hypertrigly ceridemic and had higher coronary scores than normotriglyceridemic pat ients. Of the major plasma lipoproteins, triglycerides and cholesterol in the low-density lipoprotein (LDL) fraction were associated with gl obal coronary atherosclerosis, whereas LDL triglycerides and high-dens ity lipoprotein (HDL) cholesterol correlated directly and inversely, r espectively, with the coronary stenosis score. Plasma apolipoprotein B correlated with both coronary scores. The plasma concentrations of li pid and protein in the very-low-density lipoprotein (VLDL) subfraction s (VLDL1 through VLDL3) and intermediate-density lipoprotein (IDL) did not correlate with either of the coronary scores, whereas the concent ration of triglycerides in dense LDL (density >1.040 kg/L) was strongl y associated with both coronary scores. Compositional analysis of the smallest VLDL particles (VLDL3) and IDL revealed a correlation between the number of cholesteryl ester molecules in small VLDL and global co ronary atherosclerosis in hypertriglyceridemic patients. Conclusions. Global coronary atherosclerosis and distinct stenoses in young postinf arction patients are associated with the number of apolipoprotein B-co ntaining particles in plasma and the concentration of LDL triglyceride . Specifically, dense triglyceride-rich LDL particles and, in hypertri glyceridemic patients, small cholesteryl ester-rich VLDL particles rel ate to coronary artery disease severity.