High-density lipoproteins in myocardial infarction survivors.

Subjects with existing coronary heart disease and those with many of the conditions associated with increased risk of coronary disease have reduced levels of high-density lipoprotein (HDL) cholesterol. Since HDL cholesterol is only one index of HDL composition, a reduction of HDL cholesterol could reflect a change in HDL composition and/or a decrease in all HDL constituents. Therefore the present studies assessed the major apolipoproteins of HDL, A-I and A-II, in addition to HDL cholesterol in 90 male myocardial infarction (MI) survivors and their lipid-matched male controls. The MI survivors had significantly lower (p < 0.01) A-I (112 ± 2 mg/dl, mean ± SEM), A-II (29 ± 1 mg/dl), and HDL cholesterol (39 ± 1 mg/dl) than the lipid-matched control group (A-I, 121 ± 2; A-II, 33 ± 1; HDL cholesterol, 43 ± 1) and than a population-based male control group (n = 172; A-I, 121 ± 2; A-II, 33 ± 1; HDL cholesterol, 45 ± 1). The HDL cholesterol/A-I ratio in the MI survivors was slightly lower than the ratio in the lipidmatched control group but significantly lower (P < 0.02) than that in the population-based control group. The HDL cholesterol of both control groups was significantly negatively related to log triglyceride (r = ?0.43). Similarly the HDL cholesterol of the MI survivors was inversely correlated with log triglyceride (r = ?0.51), but the slope of this relationship was significantly steeper in the MI survivors. These results are consistent with a relative decrease of HDL in MI survivors over and above that attibutable to their increased triglyceride levels.