Episode 11 - Pulmonary Embolism: Part 1 - The Age-Adjusted D Dimer

Network Five Emergency Medicine

Theme:
Pulmonary Embolism.

Participants:
Dr Kevin Lai (senior emergency physician), Dr Arwen Morath (emergency physician), Dr Pramod Chandru, Naveendran Rajendran, Harry Hong, Samoda Wilegoda Mudalige, Kit Rowe and Caroline Tyers.

Discussion:
Robert-Ebadi, H., Robin, P., Hugli, O., Verschuren, F., Trinh-Duc, A., & Roy, P. et al. (2021). Impact of the Age-Adjusted D-Dimer Cutoff to Exclude Pulmonary Embolism. Circulation, 143(18), 1828-1830. https://doi.org/10.1161/circulationaha.120.052780.

Presenter:
Naveendran Rajendran - ED Resident at Westmead Hospital.

Summary:

• This was a multinational, prospective, diagnostic outcome study designed to determine the impact of the use of age-adjusted D-dimer on clinical practice in the outpatient setting.
• This study follows on from the ADJUST-PE study released in 2014, which established the safety of using an age-adjusted D-dimer cut-off retrospectively.
• The primary outcome was the incidence of symptomatic thromboembolic events in the period following which a PE had been excluded in a patient based on a negative D-dimer (with the age-adjusted cut-off), and a low pre-test probability.
• The secondary outcome looked at the number of D-dimer results which sat between the conventional cut-off of 0.5 and the age-adjusted value in the whole cohort, as well as more specifically in those aged over 75 years (to determine the diagnostic yield of the age-adjusted cut-off).
• Of the 1421 patients with a low pre-test probability for PE and a D-dimer below 0.5, only 1 was found to have a non-fatal PE.
• The proportion of patients with D-dimers that fell between the conventional cut-off of 0.5 and the age-adjusted cut-off was 301 of 1507 patients, with 0 identified thromboembolic events noted during follow-up.
• This translates to a 20% increase in the number of negative D-dimer tests using the age-adjusted cut-off, with an even more pronounced increase of 67% in the group of patients over the age of 75.

Take-Home Points:

• The age-adjusted D-dimer is a potential tool to assist with risk-stratifying patients presenting with possible PE.
• Previous concerns regarding various assays may have limited the implementation of an age-adjusted D-dimer in prior years.
• Further audits to quantify the impact of utilizing the age-adjusted D-dimer (with regards to imaging, treatment, costs, etc.) are required.

References:

• Righini M, Van Es J, Den Exter P. Age-Adjusted D-Dimer Cutoff Levels to Rule Out Pulmonary Embolism: The ADJUST-PE Study. Journal of Vascular Surgery. 2014;59(5):1469.

Credits:
This episode was produced by the ­­­­Emergency Medicine Training Network 5 with the assistance of Dr Kavita Varshney and, Deepa Dasgupta.

Music/Sound Effects

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See you next time,
Caroline, Kit, Pramod, Samoda, and Shreyas.

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