Is the Ordering of Imaging for Suspected Venous Thromboembolism Consistent With D-dimer Result?
Presented as an abstract at the Society for Academic Emergency Medicine annual meeting, May 2008, Washington, DC.
Received 23 November 2008; received in revised form 11 February 2009 and 24 February 2009; accepted 11 March 2009. published online 27 April 2009.
Study objective
We assessed whether the ordering of imaging studies in patients with suspected venous thromboembolism was consistent with the results of D-dimer testing.
Methods
We performed a retrospective chart review of consecutive cases in which a D-dimer assay was performed at an urban academic emergency department during a 13-month period. Measurements included D-dimer result and results of imaging for venous thromboembolism. The primary outcome measure was the percentage of patients in each D-dimer category (positive or negative result with a cutoff value of 500 ng fibrinogen equivalent units/dL) who underwent subsequent imaging within 48 hours. We also report the results of the imaging studies obtained.
Results
A total of 553 D-dimer tests were ordered, with 266 (48.1%) negative and 287 (51.9%) positive results. Of patients with a negative D-dimer result, 37 (14%; 95% confidence interval [CI] 10% to 19%) underwent at least 1 imaging study. Of patients with a positive D-dimer result, 137 (48%; 95% CI 42% to 54%) did not undergo imaging.
Conclusion
Evaluation for venous thromboembolism occasionally proceeded despite a negative D-dimer result, whereas frequently no further evaluation occurred despite a positive result. These findings suggest that actual clinical practice differs from what is recommended by published algorithms that guide evaluation of patients with suspected venous thromboembolism.
Department of Emergency Medicine, Alameda County Medical Center–Highland Hospital, Oakland, CA
Address for correspondence: Nathan A. Teismann, MD, Department of Emergency Medicine, Alameda County Medical Center–Highland Hospital, 1411 East 31st Street, Oakland, CA 94602; 415-609-8195, Fax 510-437-8322
Supervising editor: Allan B. Wolfson, MD
Author contributions: NAT and BF conceived the study and designed the trial. NAT and PTC abstracted data from patients' electronic medical records and organized the data. NAT drafted the article, and all authors contributed substantially to its revision. NAT takes responsibility for the paper as a whole.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. The authors have stated that no such relationships exist. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement.
Publication date: Available online April 25, 2009.
ABSTRACT