Is It Time to Adjust D-dimer Thresholds to Our Clinical Pretest Probability?

Written by Bo Stubblefield

Spoon Feed
Using the Wells Score to categorize patients as low, moderate, or high clinical pretest probability in conjunction with adjusted positive D-dimer thresholds at >1000 ng/mL for a low or >500 ng/mL for a moderate Wells Score, the authors reduced diagnostic chest imaging in the ED with no incidence of missed venous thromboembolism (VTE) at 90 days.

Why does this matter?
We can reduce imaging for PE by increasing the D-dimer threshold or by using the D-dimer test to rule out PE in more than just patients with a low pretest probability. Historically, age-adjusted D-dimer and the YEARS criteria are examples. Using clinical pre-test probability to adjust a D-dimer threshold has also been done. PEGeD is a prospective validation of this prior work.

“Dr. Wells or: How I learned to stop imaging and love the D-dimer”
This was a multicenter, prospective trial performed in Canada which enrolled 2,017 adult patients with signs or symptoms suggestive of PE.  Study outcomes were assessed at 90 days after initial diagnostic testing. When compared to a standard strategy of low clinical pretest probability and a D-dimer <500, there was a relative reduction of 34% in chest imaging using the PEGeD strategy (outlined in the Spoon Feed). Of the 1,970 patients that had low or moderate clinical pretest probability, 1,325 had negative D-dimers at the predefined thresholds and none of these patients had VTE during the 90 day follow-up. The majority of the benefit was found in the low pretest probability patients with D-dimers <1000, as only 11% patients had a moderate clinical pretest probability and only 18% of those had a negative D-dimer. The authors compared their D-dimer adjusted threshold criteria to both age-adjusted and YEARS criteria with the PEGeD strategy showing a larger reduction in imaging compared to both. Granted, this study used the Wells score to categorize patients’ pretest probability, and it is uncertain whether the same approach to D-dimer interpretation without using a clinical prediction tool would have the same result. One wonders…physician gestalt isn’t too bad.

Another Spoonful

• REBEL EM

• The Bottom Line

• EM Lit of Note

Source
Diagnosis of Pulmonary Embolism with d-Dimer Adjusted to Clinical Probability. N Engl J Med. 2019 Nov 28;381(22):2125-2134. doi: 10.1056/NEJMoa1909159.

Open in Read by QxMD

Reviewed by Clay Smith 

---

VTE Articles You Need to Know

1. Righini M, Van Es J, Den Exter PL, et al. Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study. JAMA 2014;311:1117-24.

2. American College of Emergency Physicians Clinical Policies Subcommittee on Thromboembolic D, Wolf SJ, Hahn SA, et al. Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Suspected Acute Venous Thromboembolic Disease. Annals of emergency medicine 2018;71:e59-e109.

3. van der Hulle T, Cheung WY, Kooij S, et al. Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study. Lancet 2017;390:289-97.

4. Kabrhel C, Van Hylckama Vlieg A, Muzikanski A, et al. Multicenter Evaluation of the YEARS Criteria in Emergency Department Patients Evaluated for Pulmonary Embolism. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine 2018;25:987-94.

5. van der Pol LM, Dronkers CEA, van der Hulle T, et al. The YEARS algorithm for suspected pulmonary embolism: shorter visit time and reduced costs at the emergency department. Journal of thrombosis and haemostasis : JTH 2018;16:725-33.

6. Blondon M, Le Gal G, Meyer G, Righini M, Robert-Ebadi H. Age-adjusted D-dimer cutoff for the diagnosis of pulmonary embolism: a cost-effectiveness analysis. Journal of thrombosis and haemostasis : JTH 2020.

7. Sharif S, Eventov M, Kearon C, et al. Comparison of the age-adjusted and clinical probability-adjusted D-dimer to exclude pulmonary embolism in the ED. Am J Emerg Med 2019;37:845-50.

8. Schriger DL, Elder JW, Cooper RJ. Structured Clinical Decision Aids Are Seldom Compared With Subjective Physician Judgment, and Are Seldom Superior. Annals of emergency medicine 2017;70:338-44 e3.

9. Kline JA, Stubblefield WB. Clinician gestalt estimate of pretest probability for acute coronary syndrome and pulmonary embolism in patients with chest pain and dyspnea. Annals of emergency medicine 2014;63:275-80.