• Sydney Char and Hyo-Chun Yoon.
• Summer Research Assistant in Diagnostic Imaging. She is studying Biomedical Engineering at Tufts University in Medford, MA. sydchar57@gmail.com.
• Perm J. 2014 Jan 1;18(4):10-5.

ObjectiveTo determine whether the implementation of an increased D-dimer threshold value and clinical probability assessment increases the prevalence of pulmonary embolism (PE) in patients undergoing pulmonary computed tomography angiography (PCTA) in an Emergency Department setting.MethodsA retrospective review of all patients undergoing PCTA during 2 separate 12-month intervals, 1 before the implementation of an increased D-dimer threshold and recommendation for formal clinical probability assessment and the other after regional implementation. The primary outcome measure was the prevalence of acute PE in each of the samples.ResultsAfter the implementation of the increased D-dimer threshold and recommendation for formal clinical probability assessment, the prevalence of PE detected by PCTA increased from 4.7% to 11.7% (p < 0.001). Among all PCTAs performed after the new guidelines were promulgated, 8.6% were still performed on patients who had serum D-dimer values lower than the threshold of 1.0 µg/mL. Despite the recommendation for formal clinical probability assessment before ordering a PCTA, only 4% of patients had a formal clinical probability assessment recorded in their electronic medical record.ConclusionThe implementation of an increased D-dimer threshold value increased the prevalence of PE in patients undergoing PCTA in an Emergency Department setting, but more consistent application of clinical probability assessment remains an elusive target.

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