Increased frequency of lipoprotein disorders similar to type III hyperlipoproteinemia in survivors of myocardial infarction in Japan.

We have investigated serum lipids, lipoproteins and apolipoprotein levels in 97 survivors of acute myocardial infarction in order to clarify the characteristics of lipid and lipoprotein disorders in coronary artery disease among Japanese. Although the HDL cholesterol level was lower and the atherogenic index was higher in the myocardial infarction (MI) group than in the control group, in agreement with previous papers, there was no significant difference in total serum cholesterol level between the MI and the control groups. On the other hand, the triglyceride level was significantly higher in the MI group. The MI group also had higher levels of both cholesterol and triglyceride in the VLDL fraction (d less than 1.006) with a statistically significant increase in the ratio of cholesterol to triglyceride compared with the control group. Levels of both lipids in the IDL fraction (1.006 less than d less than 1.019) were higher in the MI group than in the control group. Lipoprotein analysis with PAG disc electrophoresis revealed a more frequent occurrence of a "midband", which appeared as an additional band between the LDL and VLDL positions, in the MI group than in the control group (MI:51% versus control: 25%, P less than 0.02). The midband-positive subgroup had a higher ratio of cholesterol to triglyceride in the VLDL fraction and higher levels of both lipids in the IDL fraction. Isoelectric focusing of apo VLDL revealed that the incidence of the suspected apo E-ND (E3/2 or E4/2) constitution, which was determined by a low ratio (less than 1.1) of the peak area of E3 to that of E2, was three times higher in the MI group than in the control group (MI:25% versus control: 7%).(ABSTRACT TRUNCATED AT 250 WORDS)