title: Value of D-dimer testing for the exclusion of pulmonary embolism in patients with previous venous thromboembolism.
abstract: BACKGROUND
  D-dimer levels remain elevated in many patients after completion of a 6-month anticoagulant drug course for a first episode of venous thromboembolism (VTE), which may limit the clinical usefulness of D-dimer testing for ruling out a possible recurrence.
  
  
  METHODS
  We assessed the safety and usefulness of D-dimer testing in patients with suspected pulmonary embolism (PE) who had experienced a previous VTE. We analyzed data from 2 outcome studies that enrolled 1721 consecutive emergency department patients with clinically suspected PE. Information on the existence of a previous episode of VTE was abstracted from the database. All the patients underwent a sequential diagnostic workup, including an enzyme-linked immunosorbent assay D-dimer test and a 3-month follow-up.
  
  
  RESULTS
  The proportion of confirmed PE was 24.1% (415/1719); PE was ruled out by a negative D-dimer test result in 32.7% (462/1411) of the patients without previous VTE but in only 15.9% (49/308) of the patients with previous VTE (P<.001). The 3-month thromboembolic risk was 0% (95% confidence interval, 0.0%-7.9%) in patients with previous VTE and a negative D-dimer test result. The 2-fold lower chance of a negative D-dimer test result in patients with previous VTE was independent of older age, active malignancy, fever, and recent surgery.
  
  
  CONCLUSIONS
  In patients with suspected PE and previous VTE, a negative D-dimer test result seems to allow safely ruling out a recurrent event. However, the proportion of negative results is lower in such patients, definitely reducing the clinical usefulness of the D-dimer test in that subgroup.
authors.affiliation: Department of Internal Medicine and Chest Diseases, Brest University Hospital, Brest, France. gregoire.legal@chu-brest.fr
authors.forename: Grégoire
authors.initials: G
authors.lastname: Le Gal
authors.forename: Marc
authors.initials: M
authors.lastname: Righini
authors.forename: Pierre-Marie
authors.initials: PM
authors.lastname: Roy
authors.forename: Oliver
authors.initials: O
authors.lastname: Sanchez
authors.forename: Drahomir
authors.initials: D
authors.lastname: Aujesky
authors.forename: Arnaud
authors.initials: A
authors.lastname: Perrier
authors.forename: Henri
authors.initials: H
authors.lastname: Bounameaux
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D015415:Biomarkers / Q000032:analysis; D015331:Cohort Studies; D003937:Diagnosis, Differential; D004198:Disease Susceptibility; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis* / Q000401:mortality; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013923:Thromboembolism / Q000175:diagnosis* / Q000188:drug therapy / Q000401:mortality
chemical_list: D000925:Anticoagulants; D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D