凝固能, ワルファリン血中濃度, ビタミンK類および血液凝固関連因子に関する研究

Patients who had undergone valve replacement were divided into 2 groups, the change-withtime group who had been treated with warfarin after the operation and in whom the coagulability had not reached the therapeutic range yet and the diurnal change group who had been treated with warfarin for more than 14 days and in whom the coagulability had been maintained in the therapeutic range. The relation between the coagulability, blood warfarin level, vitamin K level and coagulation factors were examined in these patients and the following became clear:1) In the change-with-time group a close negative correlation was observed between theblood warfarin level and PT value or TT value. Hence, the blood warfarin level can be used as a parameter of coagulability at the initial stage of warfarin therapy. However, no negative correlation was observed between the two and the blood warfarin level cannot be a parameter of coagulability in the diurnal change group. 2) In the change-with-time group in whom about 3mg/ day of warfarin was administered, the blood warfarin level showed a value of 666ng/ ml on the 4 th day of administration when the PT and TT values tended to be maintained within the therapeutic ranges. The PIVKA (Protein Induced by Vitamin K absence or antagonists)-II (abnormal prothrombin which occurs due to vitamin K deficiency and which has no coagulable activity) showed a value of 7AU/ ml on the same day. Furthermore, a good correlation was obtained between the PT or TT value and PIVKA-11. Hence, PIVKA-J [is useful as a parameter to evaluate the anticoagulant effect of warfarin. 3) In the change-with-time group vitamin K1-epoxide which is a metabolite of vitamin K1 became measurable at the 11 th day and an increase in concentration was observed. A correlation with the blood warfarin level was observed. Accordingly, vitamin K1-epoxide is useful as a parameter to evaluate the vitamin K cycle inhibition by warfarin. 4) In the change-with-time group protein C which has an anticoagulant effect showed the min. value of 0.72 μg/ ml on the 4 th day of warfarin administration. Protein C showed a good negative correlation with the blood warfarin level, PT and TT values, so that protein C is useful to evaluate the anticoagulant effect of warfarin. 5) Measurement of the blood level of warfarin, vitamin K1-epoxide, PIVKA-] I and protein C can be a clue to eluci date the poor maintenance of coagulability in the therapeutic range.