The prediction role of D-dimer in recurrence of venous thromboembolism 1-year after anticoagulation discontinuing following idiopathic deep vein thrombosis

Background: After discontinuing oral anticoagulant therapy (OAT), the recurrence of venous thromboembolism (VTE) is greatest in the 1st year and gradually diminishes. D-dimer assay was proposed to be eff ective in selecting patients with idiopathic DVT. Th e aim of this study was to determine the rate of VTE recurrence after discontinuing OAT according to the results of D-dimer. Materials and Methods: Th is prospective study was conducted in patients with a fi rst episode of symptomatic proximal deep vein thrombosis (DVT) who had received OAT for at least 3 months. Patients were re-evaluated at 1st, 6th and 12th months of their follow-up. At the fi rst (T0) and 30-day (T1) visits, venous blood samples were taken for D-dimer test. At each follow-up visit, we examined patients for clinical symptoms or signs of recurrent VTE, bleeding, postthrombotic manifestations, adherence to treatment, and concomitant analgesic or antiinflammatory therapy. Th e endpoint outcomes were VTE recurrence and complete of this survey follow-ups. Results: A total of 68 eligible patients was enrolled. Four patients (two patients need to use long-term oral anticoagulation, and two patients lost their fi rst follow-up) were excluded. At T0, D-dimer and compression ultrasonongraphy (CUS) was normal in 28 patients (44%). Moreover, 36 patients had abnormal D-dimer but normal CUS. A follow-up of 12 months was available in 44 patients. During the follow-up, three recurrent events were recorded. All Recurrent events were ipsilateral DVT. Among these index cases, all had an abnormal D-dimer at either T0 and/or T1. Th e recurrence rate was higher in males than in females (8.6% vs. 2.2%, P = 0.04) with an abnormal D-dimer at T0 and/or T1 with a multivariate hazard ratio of 2.1 (95% confi dence intervals [CI]: 1.2-5.2; P = 0.02). Patients older than 65 years had a higher rate of events than younger and hazard ratio was about 3.8 (95% CI: 2.1-4.2; P = 0.02). Patients with recurrences had higher mean D-dimer at both T0 and T1 when compared with those without recurrences, but the diff erence was signifi cant only for D-dimer at T1 (P = 0.03). During the follow-up, two patients died (3%). Conclusion: Within 12 months followup, the risk of recurrence with an abnormal D-dimer, either during or at 1-month after discontinuing OAT, was 4.6% which is much lower to the annual risk of recurrence in most studies with idiopathic and provoked VTE. D-dimer has an acceptable prognostic value in detecting recurrence of idiopathic VTE before discontinuing the anticoagulant therapy.