Evaluation of oral anticoagulant therapy by measuring plasma prothrombin fragment 1 + 2.
To assess the degree of haemostatic system activation, plasma levels of prothrombin fragment 1 + 2 (F1 + 2), a direct indicator for thrombin generation in vivo, were measured in 49 patients with thrombotic disease undergoing long-term warfarin therapy (Thrombotest values < or = 40%). In these patients, vitamin K dependent coagulation factors (factors II, VII, IX and X) were decreased together with the anticoagulant proteins C and S, but the mean plasma concentration of F1 + 2 was significantly decreased compared with 48 healthy subjects. In warfarin-treated patients, F1 + 2 was positively correlated with the Thrombotest value, factors II, VII, IX and X. When analysed according to the intensity of anticoagulation, patients with Thrombotest values less than 30% showed a significant decrease in F1 + 2, but the mean F1 + 2 level was normal in patients with Thrombotests higher than 30%. These findings indicate that long-term oral anticoagulant therapy suppresses thrombin generation approximately in parallel to the decrease in coagulation factors, and levels of F1 + 2 lower than healthy subjects are observed when Thrombotest values are less than 30%.
Takahashi
H
H
First Department of Internal Medicine, Niigata University School of Medicine, Japan.
Wada
K
K
Satoh
N
N
Takakuwa
E
E
Furuta
R
R
Yoshino
N
N
Shibata
A
A
D000284:Administration, Oral; D001779:Blood Coagulation Factors / Q000032:analysis; D002318:Cardiovascular Diseases / Q000097:blood / Q000188:drug therapy; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis*; D011516:Prothrombin / Q000032:analysis*; D013917:Thrombin / Q000096:biosynthesis; D014859:Warfarin / Q000008:administration & dosage / Q000627:therapeutic use*
D001779:Blood Coagulation Factors; D010446:Peptide Fragments; C045879:prothrombin fragment 1.2; D014859:Warfarin; D011516:Prothrombin; D013917:Thrombin