Studies On PIVKA-VII

Abstract

The factor VII related antigen (Pivka-VII) in 25 random patients under long term treatment with oral anticoagulants was studied. All the patients had Thrombotest levels well within the therapeutic range (3 to 11%) and had been receiving the drugs for at least 4 months. Factor VII activity (VII: C) mean levels were 8.7 u/dl(sem 0.78) and factor VII antigen (VII: Ag) mean levels were 30.7 u/dl(sem 1.99), (ratio Pivka/Activity 4.04). Barium chloride adsorbed the same mean amount of factor VII: C and factor VII: Ag (8.7 u/dl and 8.0 u/dl respectively). After exposure to cold in 4/25 subjects the “cold activation” phenomenon became evident, characterised by an increase of factor VII: C levels and immodified VII : Ag levels. In the remaining 21 patients, mean VII : C as well as VII: Ag levels did not show modifications (8.5 u/dl and 30.7 u/dl respectively). Moreover, three normal volunteers received three different oral anticoagulants ( Acenocoumarin, Coumarin and Ethyl-Biscomacetate). A sharp increase of factor VII:C levels was observed in all the three subjects (from 30 to 50%), a few hours after the beginning of the treatments, followed by consensual decrease of the two properties related to factor VII that reached the nadir after 48 hours. The vitamin K administration was followed by a rapid and consenual increase of the two parameters.