title: Simplification of the diagnostic management of suspected deep vein thrombosis.
abstract: BACKGROUND
  The standard diagnostic approach in patients with suspected deep vein thrombosis is to repeat the compression ultrasonography after 1 week in all patients with an initial normal result. We hypothesized that a normal finding of a D-dimer assay safely obviates the need for repeated ultrasonography. In addition, we evaluated the potential value of a pretest probability assessment for this purpose.
  
  
  METHODS
  At presentation, consecutive outpatients with suspected thrombosis underwent independent assessment by means of ultrasonography of the proximal veins, a whole-blood D-dimer assay, and a pretest clinical model. Patients with normal ultrasonographic findings and an abnormal D-dimer assay result were scheduled for repeated ultrasonography. We evaluated the incidence of symptomatic venous thromboembolic complications during a 3-month follow-up, and the value of clinical pretest probability with ultrasonography or D-dimer assay in scenario analyses.
  
  
  RESULTS
  We studied 1756 patients with prevalence of thrombosis of 22%. At entry, results of the D-dimer assay and ultrasonography were normal in 828 patients (47%). Of these, 6 returned with confirmed symptomatic venous thromboembolism (complication rate, 0.7%; 95% confidence interval [CI], 0.3%-1.6%). Repeated ultrasonography was avoided in 61% of the patients with an initial normal test result. Scenario analyses disclosed that the complication rate was 1.6% (95% CI, 0.8%-2.6%) in those with a low clinical pretest probability and a normal result of ultrasonography at referral, whereas this figure was 1.8% (95% CI, 0.9%-3.3%) in patients with a low clinical probability result and a normal result of the D-dimer assay at referral.
  
  
  CONCLUSIONS
  It is safe to withhold repeated ultrasonography in patients with suspected deep vein thrombosis who have normal results of ultrasonograpy and the SimpliRED D-dimer assay at presentation. The combination of a low clinical pretest probability with a normal result of compression ultrasonography or the D-dimer assay appears to be equally safe in refuting the diagnosis of deep vein thrombosis.
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Roderik A
authors.initials: RA
authors.lastname: Kraaijenhagen
authors.forename: Franco
authors.initials: F
authors.lastname: Piovella
authors.forename: Enrico
authors.initials: E
authors.lastname: Bernardi
authors.forename: Fabio
authors.initials: F
authors.lastname: Verlato
authors.forename: Erik A M
authors.initials: EA
authors.lastname: Beckers
authors.forename: Maria M W
authors.initials: MM
authors.lastname: Koopman
authors.forename: Marisa
authors.initials: M
authors.lastname: Barone
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Camporese
authors.forename: Bert Jan
authors.initials: BJ
authors.lastname: Potter Van Loon
authors.forename: Martin H
authors.initials: MH
authors.lastname: Prins
authors.forename: Paolo
authors.initials: P
authors.lastname: Prandoni
authors.forename: Harry R
authors.initials: HR
authors.lastname: Büller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000933:Antifibrinolytic Agents / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D015203:Reproducibility of Results; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000097:blood* / Q000000981:diagnostic imaging*
chemical_list: D000933:Antifibrinolytic Agents; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D