Evaluation of a Dose-Monitoring Method for Prophylactic Anticoagulant Therapy with Low-Molecular-Weight Heparin

Objective: In the present study, we report on the results of our investigation of optimum dose monitoring using coagulation and fibrinolytic system indicators during obstetric prophylactic anticoagulant therapy with enoxaparin. Study Design: Of 103 cases of cesarean section performed at our hospital, 37 cases were selected for this study after obtain ing their consent for blood collection. Variables of the coagulation and fibrinolytic systems [anti-factor Xa activity, endogenous thrombin potential (ETP), prothrombin time (PT) or international normalized ratio (INR), activated partial thromboplastin time (APTT) and D-dimer levels] were determined. Results: In the 5-day administration group, the anti-factor Xa activitywas 0.0 U/ml on the postoperative day 1, increased to 0.05 U/ml ± 0.04 U/ml on the postoperative day 3, and mildly increased to 0.06 U/ml ± 0.05 U/ml on the postoperative day 5. On the other hand, the anti-factor Xa activity in the 3-day administration group was 0.0 U/ml on the postoperative day 1 (before enoxaparin administration), increased to 0.06 U/ml ± 0.05 U/ml on the postoperative day 3, and significantly decreased to 0.02 U/ml ± 0.03 U/ml on the postoperative day 5 (p = 0.003); thus, the pattern of change was significantly different from that in the 5-day administration group (p = 0.004). Enoxaparin administration did not result in any significant fluctuation of the ETP, and no significant difference was observed between the 5-day and 3-day administration groups. Conclusion: Enoxaparin administration was associated with increase of the anti-factor Xa activity, and prolonged administration led to more sustained increase of the activity.