Markers of in vivo activation of coagulation. Interrelationships change with intensity of oral anticoagulation.

Abstract

Measures of markers of in vivo activation of coagulation were assessed in patients on stable long-term oral anticoagulant therapy and analyzed with respect to the International Normalized Ratio (INR). The range of F1+2, FPA, and antithrombin--enzyme complex results (ATM) were significantly lower as compared to normals. Plasmin-antiplasmin complexes were unaffected by anticoagulation. An inverse correlation was evident between F1+2, FPA, and INR values at low intensity anticoagulation, and FPA and complexed antithrombin were correlated at high INRs. The relative ratio of plasma FPA/F1+2 and ATM/F1+2 increased with increasing INR. In conclusion, the interrelationship of these measures changes with intensity of anticoagulation as measured by INR, and appears complex. The utility of using these measures for patient monitoring awaits future clinical trials.