Abstract
TAKAHASHI, H., HANANO, M., HAYASHI, S., ARAI, Y., YOSHINO, N., TAKAKUWA, E., TATEWAKI, W., NAGAYAMA, R., TAKIZAWA, S. and SHIBATA, A. Plasma Levels of Protein C and Vitamin K-Dependent Coagulation Factors in Patients on Long-Term Oral Anticoagulant Therapy. Tohoku J. exp. Med., 1986, 149 (4), 351-357-Plasma levels of protein C (PC) and vitamin K-dependent coagulation factors (factors II, VII, IX and X) were measured in 100 specimens from patients on long-term warfarin therapy. Both activities and antigens of these coagulation factors were decreased, depending on the thrombotest values. Factor II activity/ antigen ratio and factor X activity antigen ratio were correlated well with thrombotest values, indicating that the concentration of inactive molecules (PIVKAs) relative to normal proteins increases with increasing intensity of anticoagulation. Although PC antigen (PC: Ag) was also decreased, the ratios between PC: Ag and vitamin K-dependent coagulation factor antigens remained constant, being independent of the intensity of warfarin therapy. These findings indicate that long-term oral anticoagulant therapy results in the suppression of the synthesis of both vitamin K-dependent coagulation factors and PC, but the production of the coagulant and anticoagulant proteins is well-balanced.
