Residual vein thrombosis and serial D-dimer for the long-term management of patients with deep venous thrombosis

BACKGROUND: The optimal long-term strategy for preventing recurrent venous thromboembolism (VTE) in patients with deep-vein thrombosis (DVT) is uncertain. METHODS: In 620 consecutive outpatients with a first proximal DVT who had completed at least three months of anticoagulation (unprovoked in 483, associated with minor risk factors in 137), the ultrasound presence of residual vein thrombosis (RVT) was assessed and defined as an incompressibility of at least 4mm. In 517 patients without RVT and with negative D-dimer, anticoagulation was stopped and D-dimer was repeated after one and three months. Anticoagulation was resumed in 63 of the 72 patients in whom D-dimer reverted to positivity. RESULTS: During a mean follow-up of three years, recurrent VTE developed in 40 (7.7%) of the 517 patients, leading to an annual rate of 3.6% (95% CI, 2.6 to 4.9): 4.1% (95% CI, 2.9 to 5.7) in individuals with unprovoked DVT, and 2.2% (95% CI, 1.1 to 4.5) in those with DVT associated with minor risk factors. Of the 233 males with unprovoked DVT, 17 (7.3%) developed events in the first year of follow-up. Major bleeding complications occurred in 8 patients while on anticoagulation, leading to an annual rate of 1.2% (95% CI, 0.6 to 2.4). CONCLUSIONS: Discontinuing anticoagulation in patients with a first episode of proximal DVT based on the assessment of RVT and serial D-dimer leads to an overall annual rate of recurrent VTE lower than 5.0%, which is the rate deemed as acceptable by the Subcommittee on Control of Anticoagulation of the ISTH. However, in males with unprovoked DVT there is room for further improving the long-term strategy of VTE prevention. (ClinicalTrials.gov number, NCT01285661).