[Influence of oral anticoagulant treatment on D-dimers levels].

The usefulness of D-dimers determination for the exclusion of deep vein thrombosis (DVT) has been extensively studied. The persistence of high levels of D-dimers has also been suggested as a marker of hypercoagulability in rare studies and might be used to identify patients at risk for recurrent DVT. We have studied the influence of oral anticoagulant treatment in 149 patients, 17 to 84 year-old, with a history of venous thromboembolism; 81 received oral anticoagulant treatment, 68 did not. Patients with known reasons for high level of D-dimers such as cancer were excluded. Thrombophilia was found in 84 patients. D-dimers measurements were performed by ELFA technique using Vidas (bioMérieux, France) analyzer. A significantly lower level of D-dimers was observed in patients under oral anticoagulant compared to patients without this treatment, 197 +/- 134 mug/L versus 399 +/- 239 mug/L, respectively (p < 0.001). A level upper the normal value (500 mug/L) was found in only 3 patients out of 81 receiving an oral anticoagulant treatment as compared with 21 of the 68 patients without treatment. This decrease of D-dimers in patients receiving oral anticoagulants was the same in the different age populations. There was no correlation between INR and D-dimers levels in this study. The clinician should be informed of the decrease of D-dimers in patients treated with anticoagulants. The decrease of D-dimers plasma level during oral anticoagulant treatment suggest that D-dimers concentration in plasma is an indirect marker of reduced clotting activity in vivo.