[The application of thrombin generation tests to warfarin anticoagulation monitoring].
OBJECTIVE
To explore the thrombin generation capacity in patients on warfarin therapy with different prothrombin time international normalized ratio (PT-INR), the capacity in relation to bleeding, and the application of thrombin generation tests to warfarin therapy monitoring.


METHODS
Seventy eight blood samples were taken from patients on warfarin therapy for more than 3 months owing to valve replacement or atrial fibrillation. The patients' case history and PT-INR were collected and thrombin generation tests were performed in all samples.


RESULTS
Patients were ranked into three groups according to different PT-INR. There were 23 patients in group I with PT-INR from 1.51 to 2.00, 39 patients in group II with PT-INR from 2.01 to 3.00, and 16 patients in group III with PT-INR from 3.01 to 4.26. There were significant differences between each two of the three groups in lag time, peak, and ttpeak (time to peak) (P <0.01). There was a significant difference between group I and group II in endogenous thrombin potential (ETP) (P = 0.0001), but not between group II and group III (P= 0.06). Five patients developed bleeding and their ETP was less than 15% of normal control.


CONCLUSIONS
In patients on warfarin therapy, when the PT-INR was more than 3.0, increasing the dose of warfarin doesn' t decrease the thrombin generation, but increase bleeding risk. PT-INR combined with ETP may better reflect patient's coagulation status, therefore be of more significance in preventing bleeding.
Chen
Hua-Yun
HY
Clinical Transfusion Department, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Ding
Qiu-Lan
QL
Zhang
Li-Wei
LW
Xu
Guan-Qun
GQ
Dai
Jing
J
Wang
Xue-Feng
XF
Xi
Xiao-Dong
XD
Wang
Hong-Li
HL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000201:enzymology; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000517:prevention & control; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011517:Prothrombin Time; D013917:Thrombin / Q000096:biosynthesis*; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
D000925:Anticoagulants; D014859:Warfarin; D013917:Thrombin