Imaging/original researchIncidence and Predictors of Repeated Computed Tomographic Pulmonary Angiography in Emergency Department Patients
Introduction
Pulmonary embolism manifests a wide variety of clinical presentations, ranging from classic (eg, sudden onset of dyspnea in a patient with risk factors and abnormal vital signs), to atypical (eg, altered mental status with normal vital signs).1 If undiagnosed, pulmonary embolism can kill rapidly.2 As a result, emergency physicians have a low threshold for ordering diagnostic testing for pulmonary embolism.3 Most emergency physicians in the United States rely on contrast-enhanced computed tomographic (CT) pulmonary angiography as a definitive diagnostic test to diagnose and exclude pulmonary embolism.3 Clinical practice guidelines generally suggest that emergency clinicians use pretest probability before testing for pulmonary embolism.4, 5 Clinical features that increase risk of pulmonary embolism in the emergency department (ED) setting include older age, unexplained dyspnea, increased pulse rate, low pulse oximetry reading, recent surgery, immobility, history of malignancy, and previous venous thromboembolism.6, 7, 8 These risk factors recur as fixed or intermittent features of the clinical picture each time the patient presents to the ED, leading to recurrent CT pulmonary angiography scanning. To address this issue, we report longitudinal follow-up data from a cohort of patients who underwent first-time CT pulmonary angiography in 2001 to 2002.
Section snippets
Theoretical Model of the Problem
Radiation and contrast material increase risk of malignancy and kidney injury.9, 10 These toxicities, together with the economic cost, provide motivation to avoid repeated CT pulmonary angiography, especially if the repeated CT pulmonary angiography images seldom show emergency radiologic findings. Accordingly, the first objectives of this study were to measure the frequency of repeated CT pulmonary angiography scans during 5 years and categorize the clinical significance of the radiologic
Results
From January 1, 2001, until September 30, 2002, we enrolled 695 unique patients who underwent what we believe was their first CT pulmonary angiography ordered from within our hospital system. (Hereafter, the day of enrollment will be referred to as the index visit.) Follow-up in 2007 was incomplete in 20 of 695 (3%) patients for the following reasons: unexplained absence of patient identification in any of 3 databases (n=12), no evidence of the written order or report of the first CT pulmonary
Limitations
Our estimated frequency of repeated CT pulmonary angiography scanning is based on data from the Carolinas Healthcare System, and this limitation probably caused underestimation of the primary outcome. However, because all patients in this study were prescreened by a clinical protocol that included pretest probability assessment and D-dimer and alveolar dead-space testing, if our population is compared with that of an ED that uses no such protocol, it might be found that our patients were
Discussion
Use of CT imaging in the ED has increased sharply in the past decade. Approximately 10% of all ED patients undergo some type of CT scan, and about half of these include intravenous contrast.17 A recent multicenter study of 12 US EDs and 1 New Zealand ED found that approximately 1.5% of all ED patients underwent CT pulmonary angiography to evaluate for suspected pulmonary embolism.3 Each CT pulmonary angiography scan poses inherent risk, including probable increased risk of cancer and contrast
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2018, Thrombosis ResearchPulmonary embolism rule-out criteria (PERC) rule in European patients with low implicit clinical probability (PERCEPIC): a multicentre, prospective, observational study
2017, The Lancet HaematologyCitation Excerpt :In overcrowded emergency departments, this decrease in the length of stay is beneficial not only for patients with low clinical probability and negative PERC but also for all emergency department patients.27 Moreover, PERC rule implementation could avoid potential adverse effects (eg, radiation exposure and iodinated contrast injection), cost-effectiveness imbalance, and incidental findings, which not only cause anxiety among patients but also prompt a series of follow-up imaging studies.28 Of note, the diagnostic strategy applied in our study was based, in case of low or moderate clinical probability, on a D-dimer test with age-adjusted cutoff (age × 10 in patients aged 50 years or older) but without any implication for patients with negative PERC (by definition, younger than 50 years) and we did not observe any false negatives of the age-adjusted cutoff during follow-up.29,30
Best Clinical Practice: Current Controversies in Pulmonary Embolism Imaging and Treatment of Subsegmental Thromboembolic Disease
2017, Journal of Emergency Medicine
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Supervising editor: William R. Mower, MD, PhD
Author contributions: JAK conceived the work, obtained funding, supervised the project, performed database queries, contributed to the primary analyses, and wrote the article. DMC performed the statistical and graphic analyses and edited the article. DMB, MCK, and MS performed database queries, data entry, and assisted with article production. JAK 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. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. JAK is inventor on US patent numbers 6,575,918; 6,881,193; 7,104,964. JAK owns stock in a company involved in developing a medical device referenced herein.
Publication date: Available online October 5, 2008.