Coumarin anticoagulants impair the biological activity of the vitamin K-dependent procoagulant and anticoagulant proteins. There are no reports that focus on the levels of these proteins in over-anticoagulated patients. Therefore, we determined the levels of factor II, factor VII, factor IX and factor X, protein C and protein S in 25 randomly selected over-anticoagulated patients (International Normalized Ratio ≥ 6.0) and in 25 matched, therapeutically anticoagulated patients with an International Normalized Ratio within the therapeutic zone. Furthermore, to study a possible effect of the cause of over-anticoagulation, coagulant levels were compared between 16 over-anticoagulated patients with fever in the preceding 2 weeks and 24 over-anticoagulated patients with stable congestive heart failure. The pattern of procoagulant level reductions in the three groups of over-anticoagulated patients was largely the same as in therapeutically anticoagulated patients: factor X was the lowest and factor IX the highest. The difference was that, in over-anticoagulated patients, factor VII was relatively low among the procoagulant factors compared with therapeutically anticoagulated patients. Protein C was lower than protein S in over-anticoagulated patients with congestive heart failure, but was similar to protein S in the other study groups. In over-anticoagulated patients with fever, the vitamin K-dependent coagulation proteins except factor X were significantly lower than in over-anticoagulated patients with congestive heart failure, especially factor VII and protein S.

Additional Metadata
Keywords Anticoagulant proteins, Coumarin anticoagulants, Levels, Over-anticoagulation, Procoagulant factors
Persistent URL dx.doi.org/10.1097/00001721-200212000-00010, hdl.handle.net/1765/72520
Journal Blood Coagulation and Fibrinolysis
Citation
Penning-Van Beest, F.J.A, Gómez García, E.B, van der Meer, F.J.M, van Meegen, E, Rosendaal, F.R, & Stricker, B.H.Ch. (2002). Levels of vitamin K-dependent procoagulant and anticoagulant proteins in over-anticoagulated patients. Blood Coagulation and Fibrinolysis, 13(8), 733–739. doi:10.1097/00001721-200212000-00010