LIPID-RELATED HEMOSTATIC ABNORMALITIES IN THE ELDERLY - IMBALANCE BETWEEN COAGULATION AND FIBRINOLYSIS

To clarify age-related and lipid-related hemostatic abnormalities in the elderly, we measured the plasma levels of active PAI-I antigen (aPAI-1), tPA-PAI-1 complex (TPC), plasminogen, alpha 2-plasmin inhibitor (alpha 2-PI), plasmin-alpha 2-PI complex (PIC), and D-dimer, together with the plasma levels of fibrinogen, factor VII (F VII), and thrombin-antithrombin III complex (TAT) and the serum lipid levels in 68 hyperlipidemic and 82 normolipidemic elderly subjects. The aPAI-1 ratio was calculated as aPAI-1/(aPAI-1 + TPC). In the normolipidemic elderly subjects, plasma PIC and D-dimer levels were much higher when compared with healthy young controls, and there was also a decrease in plasma plasminogen and alpha 2-PI levels, an increase in plasma TPC levels, and high plasma F VII and fibrinogen levels. In elderly subjects with type IIb hyperlipidemia, both the plasma aPAI-1 level and the aPAI-1 ratio were significantly increased, while the plasma PIC and D-dimer levels were reduced despite higher plasma F VII, fibrinogen and TAT levels. Both serum total cholesterol and triglyceride levels were correlated positively with plasma F VII and TAT levels and with the TAT/PIC ratio, while only serum triglyceride levels showed a positive correlation with plasma TPC and aPAI-1 levels and with the aPAI-1 ratio. Thus, an increase of fibrinolytic activity appears to occur as part of normal aging to balance the increase of procoagulant activity. However, an imbalance between thrombin activity (increased procoagulant activity) and plasmin activity (hypofibrinolysis) appears to occur in elderly individuals with hyperlipidemia, perhaps resulting in a predisposition to thromboembolic disease.