Can D-dimer Still Rule Out PE in COVID-19 Patients?

Written by Meghan Breed

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A negative D-dimer performed similarly in predicting a 30-day risk of pulmonary embolism (PE) regardless of a patient’s COVID-19 status.

Why does this matter?
Patients who seek care in the emergency department (ED) and are ultimately diagnosed with either COVID-19 or PE often present with similar symptoms.  Use of the D-dimer as a diagnostic tool to risk stratify low to moderate risk patients with suspected PE avoids unnecessary imaging and its associated downstream consequences, including non-significant incidental findings, cost to the patient, and time in the ED. D-dimer has been shown to be accurate in COVID patients in a smaller, retrospective study early in the pandemic. What does this larger study show?

The D-Dimer continues to dominate diagnostically in the domain of COVID
Patient data was retrospectively reviewed from a large Canadian database. Patients were included in this study if there was clinical concern for a PE based on presenting symptoms (chest pain, shortness of breath, hypoxia, syncope, or hemoptysis). All patients had D-dimer and COVID-19 testing at the index ED visit.  10,837 patients were enrolled, of which 4,311 were COVID-19 positive. Based on chart review, authors determined what percentage of patients were diagnosed with a PE over the next 30 days: 3.1% of COVID-19 positive patients (2.8% diagnosed at initial visit and 0.3% diagnosed within 30 days), and 4.1% of COVID-19 negative patients were ultimately diagnosed with a PE. Authors evaluated both standard (500 mcg/mL FEU) and age-adjusted D-dimer thresholds.  Overall, the sensitivity of D-dimer was slightly lower among COVID-19 positive patients, but the negative predictive value was similar. Table 3 tells the story:

Source
Prognostic association between d-dimer thresholds and 30-day pulmonary embolism diagnosis among emergency department patients with suspected SARS-CoV-2 infection: a Canadian COVID-19 Emergency Department Rapid Response Network study. CJEM. 2023 Feb;25(2):134-142. doi: 10.1007/s43678-022-00440-8. Epub 2023 Jan 10.

Peer reviewed by Bo Stubblefield