Abstract:

Objective: To investigate the effects of warfarin anticoagulant therapy on vitamin K dependent clotting factors and down-regulation of protein C and protein S activities in anticoagulant system, as well as the effects of changes in above indic on anticoagulant balance. Methods: A total of 57 patients with pulmonary embolism or deep venous thrombosis treated with warfarin anticoagulant therapy in our hospital from January 2018 to March 2020 were enrolled, and activities of coagulation factors FⅡ, FⅦ, FⅨ, FⅩ, PC and PS were detected. International standardized ratio(INR) wasgrouped by quartile and the differences in the activity levels of coagulant and anticoagulant factors, protein C and protein S activities between 4 groups were compared. Results: There were statistically significant differences in the activity levels of each factor between different INR quartile groups (FⅡ, FⅦ, FⅩ: P<0.000 1; PC: P<0.001; FⅨ P<0.05). However, there was no significant difference in PS activity among different INR quartile groups(INR: 1.32-5.85), and INR level was negatively correlated with the activity of FⅡ, FⅦ, FⅨ, FⅩ, PC and PS (r was -0.678 7, -0.692 6, -0.376 7, -0.595 4, -0.466 6, and -0.212 2 respectively). The ratio of coagulation factor activity to anticoagulant protein activity decreased with the increase of INR. Conclusions: Although warfarin also interferes with carboxylation of vitamin K dependent clotting factors and anticoagulant proteins PC and PS, and decreasing their activity, clotting factors are affected more significantly.

Key words: Warfarin, International standardized ratio, Coagulation factor activity, Protein C activity, Protein S activity