Impairment of the diurnal fibrinolytic response in man. Effects of aging, type IV hyperlipoproteinemia, and coronary artery disease.

Diurnal patterns of plasma euglobulin fibrinolytic activity, estimated by the fibrin plate method, were determined in groups of young normal and older normal subjects, in subjects with type IV hyperlipoproteinemia, and in subjects with coronary artery disease who had normal lipid profiles. The marked diumal increases in fibrinolytic activity observed in the young normal subjects were significantly reduced in a large percent of the older normal subjects and in most of the subjects with coronary artery disease or type IV hyperlipoproteinemia. Although not conclusive, these findings were compatible with the hypothesis that an impairment in the responsiveness of the fibrinolytic system may be related to the development of coronary artery disease.