title: The prediction role of D-dimer in recurrence of venous thromboembolism 1-year after anticoagulation discontinuing following idiopathic deep vein thrombosis.
abstract: BACKGROUND
  After discontinuing oral anticoagulant therapy (OAT), the recurrence of venous thromboembolism (VTE) is greatest in the 1(st) year and gradually diminishes. D-dimer assay was proposed to be effective in selecting patients with idiopathic DVT. The aim of this study was to determine the rate of VTE recurrence after discontinuing OAT according to the results of D-dimer.
  
  
  METHODS
  This prospective study was conducted in patients with a first episode of symptomatic proximal deep vein thrombosis (DVT) who had received OAT for at least 3 months. Patients were re-evaluated at 1(st), 6(th) and 12(th) months of their follow-up. At the first (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. The 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 first 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. The 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% confidence 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 difference was significant only for D-dimer at T1 (P = 0.03). During the follow-up, two patients died (3%).
  
  
  CONCLUSIONS
  Within 12 months follow-up, 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.
authors.affiliation: Department of Internal Medicine, Alzahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Tamizifar
authors.affiliation: Department of Internal Medicine, Alzahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Padideh
authors.initials: P
authors.lastname: Oghab
authors.affiliation: Department of Cardiology, Alzahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Morteza Abdar
authors.initials: MA
authors.lastname: Esfahani
keywords: D-dimer; deep vein thrombosis; recurrent venous thromboembolism; residual vein obstruction