Role of D-dimer in guiding duration of anticoagulant therapy in the management of first unprovoked proximal lower limb deep venous thrombosis

Background
The optimal duration of anticoagulant therapy in management of patients with first episode of unprovoked deep venous thrombosis is uncertain. D-dimer test may play a role in the assessment of duration of anticoagulant therapy to decrease the rate of recurrence.
Aim
To evaluate if D dimer test can be used as predictor to guide the duration of anticoagulation in patients with first unprovoked proximal lower limb deep venous thrombosis.
Patients and Methods
One hundred patients with a first unprovoked proximal deep-vein thrombosis who completed 3 months of Vitamin K Antagonists (VKAs) and had elevated d dimer test 1 month after discontinuation of anticoagulation were randomly assigned either to resume (group A) or to discontinue treatment (group B). The patients were followed up for 1 year for recurrent venous thromboembolism and treatment complications.
Results
The mean age of the patients was 49.96±7.88 and 51.78±7.98 years for group A and B respectively. Male to female ratio was nearly similar in both groups 3:2 . The base line D-dimer level was 3.05±0.84 and 3.15±1.00 for group A and B respectively with no statistical significant difference. The mean duration of follow up was 10.6 months for both groups. The recurrence rate was higher in group B (7 cases) compared to group A (1 case) ( value 0.027) and this difference was statistically significant. No major bleeding or pulmonary embolism have been noticed in any patients during follow up.
Conclusion
Elevated D dimer test 1 month after discontinuation of 3 months anticoagulation, in the absence of recent thrombosis, could be an indicator for resumption of anticoagulant therapy for another 3 months.