Excess protamine is known to have anticoagulant effects. All of the following are true concerning the effects of excessive protamine EXCEPT:
A. An elevation in ACT
B. Altered platelet aggregation
C. Decreased fibrinolysis
D. Reduced ADP-induced platelet aggregation
The answer is C.
Protamine causes all of the following will cause INCREASED (not decreased) fibrinolysis. Excess protamine will cause an elevation in the ACT, decreased platelet aggregation (specifically reduced ADP-induced aggregation) and increased fibrinolysis. These effects of protamine will alter the clot formation kinetics which will be evident on a TEG analysis. This will result in a decrease in the the alpha angle and maximum amplitude. Studies have suggested that the heparin-protamine complexes may reduce expression of P-selectin and/or reduce calcium utilization by platelets thereby reducing platelet aggregation. Protamine may also directly affect platelet function and inhibit tissue factor induced thrombin generation.[1].