The predictability of bleeding by prothrombin times sensitive or insensitive to PIVKA during intensive oral anticoagulation

To evaluate the effect of PIVKA (Proteins Induced by Vitamin K Absence or Antagonism) on the bleeding tendency during oral anticoagulation, we studied consecutive patients intensively treated with warfarin (INR>4.8). The level of anticoagulation was measured with the PIVKA-insensitive Normotest (NT) as well as with the PIVKA-sensitive Thrombotest (TT), and the results are expressed as per cent coagulant activity. The NT/TT ratio was determined. Twenty patients with bleeding episodes had a mean NT/TT ratio of 2.06 as compared to 2.20 in 143 patients without bleeding episodes (p=0.08). As the NT/TT ratio was not higher in patients with bleedings, we conclude that PIVKA are of no importance for bleeding during anticoagulation with vitamin K antagonists.