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Kohn MA, Klok FA, van Es N. D-dimer Interval Likelihood Ratios for Pulmonary Embolism. Acad Emerg Med 2017; 24:832-837. [PMID: 28370759 DOI: 10.1111/acem.13191] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/21/2017] [Accepted: 03/25/2017] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The objective was to estimate D-dimer interval likelihood ratios (iLRs) for diagnosing pulmonary embolism (PE). METHODS The authors used pooled patient-level data from five PE diagnostic management studies to estimate iLRs for the eight D-dimer intervals with boundaries 250, 500, 750, 1,000, 1,500, 2,500, and 5,000 ng/mL. Logistic regression was used to fit the data so that an interval increase corresponds to increasing the likelihood ratio by a constant factor. RESULTS The iLR for the D-dimer interval 1,000-1,499 ng/mL was essentially 1.0 (0.98 with 95% confidence interval [CI] = 0.82-1.18). In the logistic regression model, the constant between-interval factor was 2.0 (95% CI = 1.9-2.1). Using these iLR estimates, if the pre-D-dimer probability of PE is 15%, only a D-dimer less than 500 ng/mL will result in a posttest probability below 3%; if the pretest probability is 5%, the threshold for a "negative" D-dimer is 1,000 ng/mL. CONCLUSIONS A decision strategy based on these approximate iLRs agrees with several published strategies.
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Affiliation(s)
- Michael A. Kohn
- Department of Epidemiology and Biostatistics; UCSF; San Francisco CA
- Department of Emergency Medicine; Mills-Peninsula Medical Center; Burlingame CA
| | - Frederikus A. Klok
- Department of Medicine-Thrombosis and Hemostasis; Leiden University Medical Center; Leiden the Netherlands
| | - Nick van Es
- Department of Vascular Medicine; Academic Medical Center (NvE); Amsterdam the Netherlands
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Yan Z, Ip IK, Raja AS, Gupta A, Kosowsky JM, Khorasani R. Yield of CT Pulmonary Angiography in the Emergency Department When Providers Override Evidence-based Clinical Decision Support. Radiology 2016; 282:717-725. [PMID: 27689922 DOI: 10.1148/radiol.2016151985] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To determine the frequency of, and yield after, provider overrides of evidence-based clinical decision support (CDS) for ordering computed tomographic (CT) pulmonary angiography in the emergency department (ED). Materials and Methods This HIPAA-compliant, institutional review board-approved study was performed at a tertiary care, academic medical center ED with approximately 60 000 annual visits and included all patients who were suspected of having pulmonary embolism (PE) and who underwent CT pulmonary angiography between January 1, 2011, and August 31, 2013. The requirement to obtain informed consent was waived. Each CT order for pulmonary angiography was exposed to CDS on the basis of the Wells criteria. For patients with a Wells score of 4 or less, CDS alerts suggested d-dimer testing because acute PE is highly unlikely in these patients if d-dimer levels are normal. The yield of CT pulmonary angiography (number of positive PE diagnoses/total number of CT pulmonary angiographic examinations) was compared in patients in whom providers overrode CDS alerts (by performing CT pulmonary angiography in patients with a Wells score ≤4 and a normal d-dimer level or no d-dimer testing) (override group) and those in whom providers followed Wells criteria (CT pulmonary angiography only in patients with Wells score >4 or ≤4 with elevated d-dimer level) (adherent group). A validated natural language processing tool identified positive PE diagnoses, with subsegmental and/or indeterminate diagnoses removed by means of chart review. Statistical analysis was performed with the χ2 test, the Student t test, and logistic regression. Results Among 2993 CT pulmonary angiography studies in 2655 patients, 563 examinations had a Wells score of 4 or less but did not undergo d-dimer testing and 26 had a Wells score of 4 or less and had normal d-dimer levels. The yield of CT pulmonary angiography was 4.2% in the override group (25 of 589 studies, none with a normal d-dimer level) and 11.2% in the adherent group (270 of 2404 studies) (P < .001). After adjustment for the risk factor differences between the two groups, the odds of an acute PE finding were 51.3% lower when providers overrode alerts than when they followed CDS guidelines. Comparison of the two groups including only patients unlikely to have PE led to similar results. Conclusion The odds of an acute PE finding in the ED when providers adhered to evidence presented in CDS were nearly double those seen when providers overrode CDS alerts. Most overrides were due to the lack of d-dimer testing in patients unlikely to have PE. © RSNA, 2016.
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Affiliation(s)
- Zihao Yan
- From the Center for Evidence-Based Imaging (Z.Y., I.K.I., A.S.R., A.G., R.K.), Department of Radiology (A.S.R., A.G., R.K.), Department of Medicine (I.K.I.), and Department of Emergency Medicine (A.G., J.M.K.), Brigham and Women's Hospital, Harvard Medical School, 20 Kent St, 2nd Floor, Boston, MA 02120; and Department of Emergency Medicine, Massachusetts General Hospital, Boston, Mass (A.S.R.)
| | - Ivan K Ip
- From the Center for Evidence-Based Imaging (Z.Y., I.K.I., A.S.R., A.G., R.K.), Department of Radiology (A.S.R., A.G., R.K.), Department of Medicine (I.K.I.), and Department of Emergency Medicine (A.G., J.M.K.), Brigham and Women's Hospital, Harvard Medical School, 20 Kent St, 2nd Floor, Boston, MA 02120; and Department of Emergency Medicine, Massachusetts General Hospital, Boston, Mass (A.S.R.)
| | - Ali S Raja
- From the Center for Evidence-Based Imaging (Z.Y., I.K.I., A.S.R., A.G., R.K.), Department of Radiology (A.S.R., A.G., R.K.), Department of Medicine (I.K.I.), and Department of Emergency Medicine (A.G., J.M.K.), Brigham and Women's Hospital, Harvard Medical School, 20 Kent St, 2nd Floor, Boston, MA 02120; and Department of Emergency Medicine, Massachusetts General Hospital, Boston, Mass (A.S.R.)
| | - Anurag Gupta
- From the Center for Evidence-Based Imaging (Z.Y., I.K.I., A.S.R., A.G., R.K.), Department of Radiology (A.S.R., A.G., R.K.), Department of Medicine (I.K.I.), and Department of Emergency Medicine (A.G., J.M.K.), Brigham and Women's Hospital, Harvard Medical School, 20 Kent St, 2nd Floor, Boston, MA 02120; and Department of Emergency Medicine, Massachusetts General Hospital, Boston, Mass (A.S.R.)
| | - Joshua M Kosowsky
- From the Center for Evidence-Based Imaging (Z.Y., I.K.I., A.S.R., A.G., R.K.), Department of Radiology (A.S.R., A.G., R.K.), Department of Medicine (I.K.I.), and Department of Emergency Medicine (A.G., J.M.K.), Brigham and Women's Hospital, Harvard Medical School, 20 Kent St, 2nd Floor, Boston, MA 02120; and Department of Emergency Medicine, Massachusetts General Hospital, Boston, Mass (A.S.R.)
| | - Ramin Khorasani
- From the Center for Evidence-Based Imaging (Z.Y., I.K.I., A.S.R., A.G., R.K.), Department of Radiology (A.S.R., A.G., R.K.), Department of Medicine (I.K.I.), and Department of Emergency Medicine (A.G., J.M.K.), Brigham and Women's Hospital, Harvard Medical School, 20 Kent St, 2nd Floor, Boston, MA 02120; and Department of Emergency Medicine, Massachusetts General Hospital, Boston, Mass (A.S.R.)
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van der Hulle T, den Exter PL, Erkens PGM, van Es J, Mos ICM, ten Cate H, Kamphuisen PW, Hovens MMC, Büller HR, Klok FA, Huisman MV. Variable D-dimer thresholds for diagnosis of clinically suspected acute pulmonary embolism. J Thromb Haemost 2013; 11:1986-92. [PMID: 23965032 DOI: 10.1111/jth.12394] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND Computed tomography pulmonary angiography (CTPA) is frequently requested using diagnostic algorithms for suspected pulmonary embolism (PE). For suspected deep vein thrombosis, it was recently shown that doubling the D-dimer threshold in patients with low pretest probability safely decreased the number of ultrasonograms. We evaluated the safety and efficiency of a similar strategy in patients with suspected PE. METHODS We performed a post-hoc analysis of 2213 consecutive patients of two cohort studies with suspected PE who were managed according to current standards: PE ruled out in case of unlikely probability (Wells rule ≤ 4 points) and a D-dimer level < 0.5 μg mL(-1) . CTPA was performed in all other cases. All patients were followed for 3 months. We calculated 3-month venous thromboembolism (VTE) incidence and the number of required CTPAs for selective D-dimer thresholds in patients with low clinical probability (< 2 points, D-dimer threshold < 1.0 μg mL(-1) ) and intermediate probability (2-6 points, D-dimer threshold < 0.5 μg mL(-1) ). RESULTS Using standard management, PE could be excluded without CTPA in 26% of patients, with a 3-month VTE incidence of 0.88% (95% confidence interval [CI] 0.29-2.1%). Using selective D-dimer thresholds, PE could be excluded without CTPA in 36% of patients, with a 3-month VTE incidence of 2.1% (95% CI 1.2-3.4%) in patients managed without CTPA, an increase of 1.2 percentage points (95% CI -0.3 to 2.2). CONCLUSIONS Applying selective D-dimer thresholds reduces the need for CTPA by 11 percentage points but is associated with an increased failure rate. Prospective studies should evaluate the safety and net clinical benefit of this approach.
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Affiliation(s)
- T van der Hulle
- Department of Thrombosis and Hemostasis, LUMC, Leiden, The Netherlands
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Feng LB, Pines JM, Yusuf HR, Grosse SD. U.S. trends in computed tomography use and diagnoses in emergency department visits by patients with symptoms suggestive of pulmonary embolism, 2001-2009. Acad Emerg Med 2013; 20:1033-40. [PMID: 24127707 DOI: 10.1111/acem.12221] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/12/2013] [Accepted: 05/27/2013] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Using computed tomography (CT) to evaluate patients with chest symptoms is common in emergency departments (EDs). This article describes recent trends of CT use in U.S. EDs for patients presenting with symptoms common to acute pulmonary embolism (PE). METHODS The 2001-2009 National Hospital Ambulatory Medical Care Survey (NHAMCS), a nationally representative survey of U.S. ED encounters, was used for data collection. Patients with at least one of three complaints (chest pain, dyspnea, or hemoptysis) were categorized into the chest symptom study (CSS) group. The yearly increases in CT use for the complaints were tabulated first, then linear regression analysis was used to calculate average rates of increases in CT use between 2001 and 2007, the years where CT use increased, for the overall population and among specific subgroups. The ratios of the number of visits when CT was ordered and there was a target diagnosis relative to the total number of visits with CT in the CSS group (diagnosis/CT ratio) were calculated for PE and pneumonia. RESULTS Annual CT rates for the CSS group increased from 2.6% in 2001 to 13.2% in 2007, subsequently leveling off at approximately 12.5% in 2008 and 2009. The average growth rate of CT use for the CSS group was 28.1% (95% confidence interval [CI] = 20.9% to 35.7%) per year between 2001 and 2007. Testing rates for all subgroups increased. The lowest growth rate was among Hispanic patients, whose CT rates grew 14.2% (95% CI = 5.7% to 23.5%) per year. The highest growth rate was in nonurban hospitals, at 43.1% (95% CI = 15.2% to 77.8%) per year. Patients triaged as nonurgent received the fewest CTs, compared to those who should be seen in 2 hours or less. With regard to sources of payment, the self-pay subgroup experienced the highest rate of increase at 35.1% (95% CI = 18.6% to 53.9%). The PE diagnosis/CT ratio from 2002 to 2009 was 2.7% for the CSS group. The pneumonia diagnosis/CT ratio grew from 5.8% in 2002 to 2005 to 7.8% in 2006 to 2009. CONCLUSIONS Computed tomography use in ED visits by patients with chest symptoms increased dramatically from 2001 to 2007 and seems to have leveled off in subsequent years. The low PE diagnosis-to-CT ratio suggests that EDs may need to promote evidence-based use of CT.
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Affiliation(s)
| | - Jesse M. Pines
- Department of Emergency Medicine; George Washington University; Washington DC
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