Objective To evaluate if imaging studies such as CT pulmonary angiography (CTPA) or ventilation–perfusion (V/Q) scan are ordered according to the current guidelines for the diagnosis of pulmonary embolism (PE).
Methods We performed a retrospective observational cohort study in all adult patients who presented to the Sparrow Hospital Emergency Department from January 2014 to December 2016 and underwent CTPA or V/Q scan. We calculated the Wells’ score retrospectively, and d-dimer values were used to determine if the imaging study was justified.
Results A total of 8449 patients underwent CTPA (93%) or V/Q scan (7%), among which 142 (0.2%) patients were diagnosed with PE. The Wells’ criteria showed low probabilities for PE in 96 % and intermediate or high probabilities in 4 % of total patients. Modified Wells’ criteria demonstrated PE unlikely in 99.6 % and PE likely in 0.4 % of total patients. D-dimer was obtained in only 37 % of patients who were unlikely to have a PE or had a low score on Wells’ criteria. Despite a low or unlikely Wells’ criteria score and normal d-dimer levels, 260 patients underwent imaging studies, and none were diagnosed with PE.
Conclusion More than 99 % of CTPA or V/Q scans were negative in our study. This suggests extraordinary overutilisation of the imaging methods. D-dimer, recommended in patients with low to moderate risk, was ordered in only one-third of patients. Much greater emphasis of current guidelines is needed to avoid inappropriate utilisation of resources without missing diagnosis of PE.
- Pulmonary embolism
- Computed tomography pulmonary angiography
- Ventilation–perfusion scan
- Wells’ criteria
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Presented at This study was presented as an abstract, after preliminary data analysis, at American College of Physicians, Michigan Chapter Residents day, 2018 and Mid-Michigan Research Day, 2018.
Contributors All the authors contributed to the paper. PD: planned the study and contributed to majority of the manuscript. MHI: wrote the manuscript including the introduction and the discussion. LW: assisted us in this study with statistics which included creating graphs. VA, XL, SS: assisted with data collection and with writing discussion. SP, MM, OD, ST: assisted with data collection. MPR: assisted with editing the manuscript, submission and revision of the manuscript. SR: is the senior author in the paper and he assisted with writing discussion and editing the manuscript.
Funding This research was funded by Resident-led research mini-grant from Graduate Medical Education, Inc, Sparrow Hospital.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Our study was approved by the institutional review boards at Michigan State University and Sparrow Hospital (IRB # x17-460e).
Provenance and peer review Not commissioned; externally peer reviewed.
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