title: D-dimer testing to determine the duration of anticoagulant therapy.
abstract: OBJECTIVE
  The optimal duration of oral anticoagulation after a first idiopathic venous thromboembolism is uncertain. Recent prospective observational studies show that D-dimer levels have a predictive value for the risk of recurrence. D-dimer testing may help in assessing the individual need for prolonged anticoagulation.
  
  
  RESULTS
  The recently published Prolong study investigated 608 patients with a first unprovoked venous thromboembolism who had received oral anticoagulation for at least 3 months. D-dimer testing was performed 1 month after anticoagulation withdrawal. Patients with normal D-dimer (n = 385) did not resume anticoagulation. Patients with abnormal D-dimer were randomized to resume (n = 103) or not resume (n = 120) anticoagulation. All patients were followed for an average of 1.4 years. Study outcomes occurred in 6.2% of patients with normal D-dimer, and in 15.0% and 2.9% of those with abnormal D-dimer who were allocated to stop or to resume anticoagulation, respectively.
  
  
  CONCLUSIONS
  Patients with an abnormal D-dimer measured 1 month from anticoagulation withdrawal have a significant incidence of recurrent venous thromboembolism which is reduced by resumption of anticoagulation. The risk of recurrence in patients with normal D-dimer is significantly lower. D-dimer testing can be used to regulate the duration of anticoagulation.
authors.affiliation: Department of Angiology & Blood Coagulation Marino Golinelli, University Hospital S. Orsola-Malpighi, Bologna, Italy. gualtiero.palareti@unibo.it
authors.forename: Gualtiero
authors.initials: G
authors.lastname: Palareti
authors.forename: Benilde
authors.initials: B
authors.lastname: Cosmi
authors.forename: Cristina
authors.initials: C
authors.lastname: Legnani
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D055502:Secondary Prevention
chemical_list: D000925:Anticoagulants; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D