paper of the week

Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism

JAMA. 2021;326(21):2141-2149. doi:10.1001/jama.2021.20750


  • Combination of PERC, YEARS and age adjusted DDimer has been reviewed regarding the use of advacnced imaging and detection of PE in comparison to the classical pathway (definition below)

Bottom line

  • Inclusion of YEARS criteria in workup of VTE patients can be valuable to reduce chest imaging
  • This study is not specific for pregnant patients, further clinical trials will be required

What is this paper about

  • non inferiority trial, standard PE workup versus inclusion of YEARS criteria
  • assessment of the years rule in a randomized clinical trial

Study design

  • Study design: multi center, cluster randomized cross over trial
  • Weakness:
  • randomization on center level –> patients difference leading to selection bias on center level
  • Protocol deviation leading to contamination –> author states this has been limited in this study
  • Not blinded
  • non inferiority margin 0.013 p value,
  • Study power 0. 86

Characteristic and Population

  • 18 Eds, international
  • Randomization:
    • control strategy versus intervention strategy to each center
    • Two months wash out period then cross over of each center
    • concealed randomization until beginning of trial

  • not blinded
  • Outcome measurement: inferiority measured by dection of VTE after 3 months
  • Inclusion: clinical suspicion of PE, chest pain syncope or dyspnoea
  • Exclusion of patients with high clinical suspicion and with PERC 0



  • The author states that including the Years criteria is not inferior to using a standard approach and may reduce chest imaging in patients with moderate suspicion of PE who cannot be excluded via PERC.
  • Pregnancy requires a separate trial as this paper does not mention pregnancy as a risk factor for PE. YEARs in itself has been evaluated in this setting but no clinical trials have been done.