Platelet and Fibrinogen Survival in Normal and Abnormal States of Coagulation

1. Platelet and fibrinogen survival have been studied by isotope taggingin normal and abnormal states of coagulation in humans and dogs.

2. By our technic, the normal curve of platelet survival is exponential. Evidence is given that such a curve is obtained because of random utilization ofthe platelets in the continuous process of coagulation.

3. In the postoperative subject and in the subject receiving epinephrine injections, platelet survival is shortened because the process of coagulation isspeeded up. In the hypocoagulable, the curve of platelet survival becomesmore nearly linear because random platelet destruction ceases.

4. When a massive thrombus forms, platelet survival is shortened. Evidenceis given that this may be due to escape of thrombin from the clot into thesystemic circulation—with a resultant hypercoagulable state.

5. Fibrinogen survival was not altered in those states in which increasedplatelet utilization occurred. This is explained by the theory that the alterationin the hemostatic mechanism had not penetrated to the fibrinogen-fibrin stage.

6. Hypercoagulability is defined as that state in which platelet utilization isaccelerated—whether or not thrombosis occurs.

Submitted on February 17, 1960 Accepted on December 9, 1960