UMEM Educational Pearls

Category: Vascular

Title: Ruling Out Pulmonary Embolism in Cancer Patients

Keywords: Pulmonary Embolism, Cancer (PubMed Search)

Posted: 7/7/2008 by Rob Rogers, MD (Updated: 10/18/2019)
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Ruling Out PE in Cancer Patients: Use D-Dimer??

Most of us are aware of the data that suports using a highly-sensitive d-dimer combined with low-moderate risk score to r/o PE. Sounds simple enough. What about using d-dimer in a cancer patient to rule it out? Well, this is being studied more and more.

Most of us would be a little uneasy about using a d-dimer as a stand-alone test to r/o PE in a cancer patient. After all, they have cancer, aren't they high risk?

The following study showed that the there was a VERY high negative predictive value and a VERY high sensitivity of a negative d-dimer in this group of cancer patients.


Abstract
PURPOSE: To prospectively evaluate (a) the diagnostic performance of D-dimer assay for pulmonary embolism (PE) in an oncologic population by using computed tomographic (CT) pulmonary angiography as the reference standard, (b) the association between PE location and assay sensitivity, and (c) the association between assay results and clinical factors that raise suspicion of PE. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; informed consent was obtained. Five hundred thirty-one consecutive patients were clinically suspected of having PE; 201 were enrolled (72 men, 129 women; median age, 61 years) and underwent CT pulmonary angiography and D-dimer assay. Relevant clinical history, symptoms, and signs were recorded. CT images were interpreted, and the location of emboli was recorded. The negative predictive value (NPV), positive predictive value (PPV), sensitivity, specificity, and diagnostic likelihood ratios of the D-dimer assay results were calculated. RESULTS: Forty-three patients (21%) had pulmonary emboli at CT. D-Dimer results were positive in 171 patents (85%). The NPV and sensitivity were 97% and 98%, respectively. The specificity and PPV were 18% and 25%, respectively. No association was shown between clinical history, symptoms, or signs and NPV, PPV, sensitivity, or specificity or between location of PE and sensitivity.
CONCLUSION: D-Dimer results have high NPV and sensitivity for PE in oncologic patients and, if negative, can be used to exclude PE in this population. Combining the assay with clinical symptoms and signs did not substantially change NPV, PPV, sensitivity, or specificity.

Whether this is ready from prime time or not remains to be determined, but it is interesting that we might be able to do this in the future to r/o PE in cancer patients.
 

References

King V, Vaze AA, Moskowitz CS, et al. D-dimer assay to exclude pulmonary embolism in high-risk oncologic population: correlation with CT pulmonary angiography in an urgent care setting. Radiology. 2008 Jun;247(3):854-61