INVIVO ASSESSMENT OF ANTICOAGULATION

Abstract

Autologous 125I-labeled fibrinogen was utilized to assess fibrinogen half-life in normal subjects and in patients with clotting complications before and after the administration of anticoagulants. Fibrinogen half-life varied from normal (104 h) to markedly abbreviated (13 h) in patients apparently fully anticoagulated, utilizing standard laboratory parameters. Plateauing of fibrinogen half-life values despite increased doses of heparin, or return of the half-life to normal, indicates full anticoagulation. This has permitted determination and administration of the theoretically optimal dose of heparin. In situations involving life-threatening clotting complications, such as massive pulmonary embolism, the use of 125I-labeled fibrinogen provides a means for controlling anticoagulant therapy in a rational fashion by this technique of assessing clotting.