D-dimer testing during anticoagulant therapy should be used to indicate patients who need extended anticoagulant therapy

Abstract

The prolong study showed that pts with venous thromboembolism (VTE) who had elevated D-dimer level after discontinuation of anticoagulant therapy benefit from resumption of anticoagulant therapy. It is not yet clear should D-dimer testing during anticoagulant therapy be used to indicate VTE pts who need extended anticoagulant therapy. Purpose: To estimate should D-dimer testing during anticoagulant therapy be used to indicate VTE pts who need extended anticoagulant therapy. Methods: One hundred and eleven pts (76 men) in the age 18-76 (mean 54±14) years with deep vein thrombosis (DVT) and/or pulmonary embolism (PE) were included in the study. Pts received unfractionated or low molecular weight heparin for at least 5 days followed by long-term warfarin therapy (international normalized ratio 2,0-3,0). D-dimer testing was performed at baseline and after 1, 3, 6 and 12 months of anticoagulant therapy by a quantitative assay with reagent kits "STA LIATEST D-DI" (Diagnostica Stago) with estimated cut-off level of 0,5 ug/ml. The follow-up period was 12 months. Endpoints were DVT/PE recurrences. Results: At least one episode of elevated D-dimer level during 12 months of anticoagulant therapy was detected in 22% of VTE pts. The frequency of DVT recurrences during 12 months was 11%. There were no PE recurrences. In pts with DVT recurrences, all episodes of elevated D-dimer level preceded DVT recurrences and were detected before DVT recurrences. The frequency of DVT recurrences in pts with elevated D-dimer level during anticoagulant therapy was significantly higher than in pts with normal D-dimer level – 27% vs 7,7% (p=0,022). Cox proportional hazard model showed that any episode of elevated D-dimer level during anticoagulant therapy is associated with a 4-fold increase of the risk of DVT recurrence (HR 4,43; 95% CI 1,42-13,78; p=0,01) compared in pts with normal D-dimer level during anticoagulant therapy. Conclusions: Our pilot study showed that any episode of elevated D-dimer level during 12 months of anticoagulant therapy is associated with a 4-fold increase of the risk of DVT recurrences. We suggest that VTE pts who had at least one episode of elevated D-dimer level during 12 months of anticoagulant therapy need extended anticoagulant therapy. Thus, D-dimer may be one of criteria for determination of duration of anticoagulant therapy. D-dimer testing during anticoagulant therapy also should be used to predict the risk DVT recurrences in VTE pts.