Recommended D-Dimer Use in Suspected Pulmonary Embolism Is Insufficient to Curb the Long-Term Overutilization of CT Pulmonary Angiography.

Purpose: The aim of this study was to determine whether the authors' emergency medicine department has seen a significant change in CT pulmonary angiography (CTPA) utilization or positive rates for pulmonary embolism (PE) over a 10-year period for the 2 years before and 8 years after the implementation of patient population-specific D-dimer recommendations.
Methods: A retrospective chart review was performed among all patients belonging to a geographically isolated health maintenance organization who underwent CTPA for the evaluation of acute PE in the emergency department between 2010 and 2019. The positive rate for acute PE among these studies was calculated and stratified by serum D-dimer value collected within 48 hours previously.
Results: A total of 6,013 CT pulmonary angiographic studies were reviewed, of which 40.2% had serum D-dimer ≥ 1.0 μg/mL (positive rate 10.6%), 42.5% did not have serum D-dimer drawn (positive rate 7.3%), and 17.2% had serum D-dimer < 1.0 μg/mL (positive rate 0.6%). There was a significant increase in positivity on CTPA in 2012 with the health group's formal recommendation of a D-dimer cutoff of 1.0 μg/mL. This improvement also corresponded with fewer orders for CTPA after a negative D-dimer result. However, in the following years, CTPA utilization and percentage positivity were found to be reverting to the prerecommendation statistics.
Conclusions: The failure to mandate the use of serum D-dimer with a higher threshold value for patients who are to undergo CTPA for possible PE has resulted in poor lasting compliance despite promising early results. A firmer approach is likely necessary to yield positive long-term outcomes.
(Copyright © 2021 American College of Radiology. Published by Elsevier Inc. All rights reserved.)