LO81: Optimizing the use of CT scanning for pulmonary embolism in the emergency department

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based diagnostic algorithms are not always adhered to in the Emergency Department (ED), which leads to unnecessary CT scanning. In 2013, the American College of Chest Physicians identified CT pulmonary angiography as one of the top five avoidable tests. One solution is to use a clinical prediction rule combined with the D-dimer, which safely reduces the use of CT scanning. The objective of this study was to compare the proportion of patients tested for PE in two emergency departments, who 1) had a CT-PE and 2) whose diagnosis of PE was missed. We compared these rates to those if the Wells rule and D-dimer had been applied as standard. Methods: This was a retrospective chart review of ED patients investigated for PE at two hospitals from April 2013 to March 2015 (24 months). Inclusion criteria were the ED physician ordered CT-PE, Ventilation-Perfusion (VQ) scan or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was defined as CT/VQ diagnosis of acute PE or acute PE/DVT in 30-day follow-up. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the false-negative rates were calculated. The false-negative rate was calculated as the number of patients diagnosed with PE within 30 days as a proportion of those patients who did not have a CT/VQ scan at initial presentation. Results: There were 1,189 patients included in this study. 55/1,189 patients (4.6%; 95%CI 3.6-6.0%) were ultimately diagnosed with PE within 30 days. 397/1,189 patients (33.4%; 95%CI 30.8-36.1%) had CT/VQ scans for PE. 3 out of 792 who were not scanned had a missed PE resulting in a false-negative rate of 0.4% (95% CI 0.1-1.1%). 80 patients had an elevated D-dimer or high Wells score but were not imaged. Furthermore, 75 patients who did not have an elevated D-dimer nor a high Wells score were imaged. Had Wells rule/D-dimer been adhered to, 402/1,189 patients (33.8%; 95%CI 31.9-36.6%) would have undergone imaging and the false negative rate would be 0/727, 0% (95%CI 0.0-0.5%). Conclusion: If the Wells rule and D-dimer was used in all patients tested for PE, a similar proportion would have a CT scan but fewer PEs would be missed.

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P113: Comparison of age-adjusted and clinical probability-adjusted D-dimer for diagnosing pulmonary embolism

CJEM ◽

10.1017/cem.2017.315 ◽

2017 ◽

Vol 19 (S1) ◽

pp. S116

Author(s):

S. Sharif ◽

C. Kearon ◽

M. Li ◽

M. Eventov ◽

R. Jiang ◽

...

Keyword(s):

Pulmonary Embolism ◽

False Negative ◽

False Negative Rate ◽

Retrospective Chart Review ◽

Ct Scanning ◽

Clinical Probability ◽

Negative Rate ◽

Wells Score ◽

Acute Pe ◽

D Dimer

Introduction: Diagnosing pulmonary embolism (PE) in the emergency department can be challenging due to non-specific signs and symptoms; this often results in the over-utilization of CT pulmonary angiography (CT-PA). In 2013, the American College of Chest Physicians identified CT-PA as one of the top five avoidable tests. Age-adjusted D-dimer has been shown to decrease CT utilization rates. Recently, clinical-probability adjusted D-dimer has been promoted as an alternative strategy to reduce CT scanning. The aim of this study is to compare the safety and efficacy of the age-adjusted D-dimer rule and the clinical probability-adjusted D-dimer rule in Canadian ED patients tested for PE. Methods: This was a retrospective chart review of ED patients investigated for PE at two hospitals from April 2013 to March 2015 (24 months). Inclusion criteria were the ED physician ordered CT-PA, Ventilation-Perfusion (VQ) scan or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was defined as CT/VQ diagnosis of acute PE or acute PE/DVT in 30-day follow-up. Trained researchers extracted anonymized data. The age-adjusted D-dimer and the clinical probability-adjusted D-dimer rules were applied retrospectively. The rate of CT/VQ imaging and the false negative rates were calculated. Results: In total, 1,189 patients were tested for PE. 1,129 patients had a D-dimer test and a Wells score less than 4.0. 364/1,129 (32.3%, 95%CI 29.6-35.0%) would have undergone imaging for PE if the age-adjusted D-dimer rule was used. 1,120 patients had a D-dimer test and a Wells score less than 6.0. 217/1,120 patients (19.4%, 95%CI 17.2-21.2%) would have undergone imaging for PE if the clinical probability-adjusted D-dimer rule was used. The false-negative rate for the age-adjusted D-dimer rule was 0.3% (95%CI 0.1-0.9%). The false-negative rate of the clinical probability-adjusted D-dimer was 1.0% (95%CI 0.5-1.9%). Conclusion: The false-negative rates for both the age-adjusted D-dimer and clinical probability-adjusted D-dimer are low. The clinical probability-adjusted D-dimer results in a 13% absolute reduction in CT scanning compared to age-adjusted D-dimer.

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LO55: Comparison of the age-adjusted D-dimer, clinical probability-adjusted D-dimer, and Wells rule with D-dimer for diagnosing deep vein thrombosis in the emergency department.

CJEM ◽

10.1017/cem.2020.110 ◽

2020 ◽

Vol 22 (S1) ◽

pp. S27-S27

Author(s):

S. Sharif ◽

C. Kearon ◽

M. Eventov ◽

P. Sneath ◽

M. Li ◽

...

Keyword(s):

False Negative ◽

False Negative Rate ◽

Duplex Ultrasonography ◽

Vein Thrombosis ◽

Clinical Probability ◽

Negative Rate ◽

Wells Score ◽

Wells Rule ◽

Deep Vein ◽

D Dimer

Introduction: Diagnosing deep vein thrombosis (DVT) is of critical importance because of its associated morbidity and mortality. Diagnosing DVT can be challenging in the Emergency Department (ED) due to inconsistent adherence to, and utilization of the Wells rule. Both the age-adjusted and clinical probability adjusted D-dimer have been shown to decrease ultrasound (US) utilization rates. We aimed to compare the safety and efficacy of the Wells score with D-dimer to the age-adjusted and clinical probability-adjusted D-dimer in Canadian ED patients tested for DVT. Methods: This was a health records review of ED patients investigated for DVT at two EDs over a two-year period. Inclusion criteria were ED physician ordered duplex ultrasonography or D-dimer for investigation of lower limb DVT. Patients under the age of 18 were excluded. DVT was considered to be present during the ED visit if DVT was diagnosed on duplex ultrasonography and was treated for acute DVT, or if the patient was subsequently diagnosed with pulmonary embolism (PE) or DVT during the next 30 days. Trained researchers extracted anonymized data. The Wells D-dimer, age-adjusted D-dimer, and the clinical probability-adjusted D-dimer rules were applied retrospectively. The rate of duplex ultrasonography imaging and the false negative rate was calculated for each rule. Results: Between April 1st 2013 and March 31st 2015, there were 1,198 patients tested for DVT. Of the low and moderate clinical pretest probability patients (Wells score ≤ 2), only 436 had a D-Dimer test and were eligible for our analysis. The average age of the patients was 59, 56% were female, and 4% had a malignancy. 207/436 patients (47.4%, 95%CI 42.8-52.2%) would have had US imaging for DVT if the age-adjusted D-dimer rule was used. 214/436 patients (49.1%, 95%CI 44.4-53.8%) would have had imaging for DVT if the clinical probability-adjusted D-dimer was used. If the Wells rule was used with the standard D-dimer cutoff of 500, 241/436 patients (55.2%, 95%CI 50.6-59.9%) would have had imaging for DVT. The false-negative rate for the Wells rule was 1.5% (95%CI 0.5-4.4%). The false-negative rate for the age-adjusted D-dimer rule was 1.3% (95%CI 0.4-3.8%). The false-negative rate for the clinical-probability adjusted D-Dimer was 1.8% (95%CI 0.7-4.5%). Conclusion: In comparison with the approach of the Wells score and D-dimer, both the age-adjusted and clinical probability-adjusted D-dimer diagnostic strategies could reduce the proportion of patients who require US imaging.

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P104: Evaluating the use of the pulmonary embolism rule-out criteria in the emergency department

CJEM ◽

10.1017/cem.2018.302 ◽

2018 ◽

Vol 20 (S1) ◽

pp. S93-S94

Author(s):

S. Sharif ◽

C. Kearon ◽

M. Eventov ◽

M. Li ◽

P. Sneath ◽

...

Keyword(s):

Emergency Department ◽

Pulmonary Embolism ◽

False Negative ◽

False Negative Rate ◽

Signs And Symptoms ◽

Ct Scanning ◽

Pulmonary Angiogram ◽

Ct Angiogram ◽

D Dimer ◽

Rule Out

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based algorithms are not always adhered to in the Emergency Department (ED), which leads to unnecessary CT scanning. The pulmonary embolism rule-out criteria (PERC) can identify patients who can be safely discharged from the ED without further investigation for PE. The purpose of this study is to evaluate the use of the PERC rule in the ED and to compare the rates of testing for PE if the PERC rule was used. Methods: This was a health records review of ED patients investigated for PE at two emergency departments over a two-year period (April 2013-March 2015). Inclusion criteria were ED physician ordered CT pulmonary angiogram, ventilation-perfusion scan, or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was considered to be present during the emergency department visit if PE was diagnosed on CT or VQ (subsegmental level or above), or if the patient was subsequently found to have PE or deep vein thrombosis during the next 30 days. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the negative predictive value was calculated. Results: There were 1,163 patients that were tested for PE and 1,097 patients were eligible for our analysis. Of the total, 330/1,097 (30.1%; 95%CI 27.4-32.3%) had CT/VQ imaging for PE, and 48/1,097 (4.4%; 95%CI 3.3-5.8%) patients were diagnosed with PE. 806/1,097 (73.5%; 95%CI 70.8-76.0%) were PERC positive, and of these, 44 patients had a PE (5.5%; 95%CI 4.1-7.3%). Conversely, 291/1,097 (26.5%; 95%CI 24.0-29.2%) patients were PERC negative, and of these, 4 patients had a PE (1.4%; 95%CI 0.5-3.5%). Of the PERC negative patients, 291/291 (100.0%; 95%CI 98.7-100.0%) had a D-dimer test done, and 33/291 (11.3%; 95%CI 8.2-15.5%) had a CT angiogram. If PERC was used, CT/VQ imaging would have been avoided in 33/1,097 (3%; 95%CI 2.2-4.2%) patients and the D-dimer would have been avoided in 291/1,097 (26.5%; 95%CI 24.0-29.2%) patients. Conclusion: If the PERC rule was used in all patients with suspected PE, fewer patients would have further testing. The false negative rate for the PERC rule was low.

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P136: Evaluating the use of the YEARS clinical decision rule for diagnosing pulmonary embolism in the Emergency Department

CJEM ◽

10.1017/cem.2018.334 ◽

2018 ◽

Vol 20 (S1) ◽

pp. S105-S105 ◽

Cited By ~ 1

Author(s):

S. Sharif ◽

C. Kearon ◽

M. Eventov ◽

M. Li ◽

R. Jiang ◽

...

Keyword(s):

Emergency Department ◽

Pulmonary Embolism ◽

Deep Vein Thrombosis ◽

False Negative ◽

False Negative Rate ◽

Clinical Signs ◽

Vein Thrombosis ◽

Negative Rate ◽

Deep Vein ◽

D Dimer

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based algorithms are not always adhered to in the Emergency Department (ED) and are often not used correctly, which leads to unnecessary CT scanning. The YEARS diagnostic algorithm, consisting of three items (clinical signs of deep vein thrombosis, hemoptysis, and whether pulmonary embolism is the most likely diagnosis) and D-dimer, is a novel and simplified way to approach suspected acute PE. The purpose of this study was to 1) evaluate the use of the YEARS algorithm in the ED and 2) to compare the rates of testing for PE if the YEARS algorithm was used. Methods: This was a health records review of ED patients investigated for PE at two emergency departments over a two-year period (April 2013-March 2015). Inclusion criteria were ED physician ordered CT pulmonary angiogram, ventilation-perfusion scan, or D-dimer for investigation of PE. Patients under the age of 18 and those without a D-dimer test were excluded. PE was considered to be present during the emergency department visit if PE was diagnosed on CT or VQ (subsegmental level or above), or if the patient was subsequently found to have PE or deep vein thrombosis during the next 30 days. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the false negative rate was calculated. Results: There were 1,163 patients that were tested for PE and 1,083 patients were eligible for our analysis. Of the total, 317/1,083 (29.3%; 95%CI 26.6-32.1%) had CT/VQ imaging for PE, and 41/1,083 (3.8%; 95%CI 2.8-5.1%) patients were diagnosed with PE at baseline. Three patients had a missed PE, resulting in a false negative rate of 0.4% (95%CI 0.1-1.2%). If the YEARS algorithm was used, 211/1,083 (19.5%; 95%CI 17.2-22.0%) would have required imaging for PE. Of the patients who would not have required imaging according to the YEARS algorithm, 8/872 (0.9%; 95%CI 0.5-1.8%) would have had a missed PE. Conclusion: If the YEARS algorithm was used in all patients with suspected PE, fewer patients would have required imaging with a small increase in the false negative rate.

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P115: Improving the diagnosis of pulmonary embolism in the emergency department

CJEM ◽

10.1017/cem.2020.321 ◽

2020 ◽

Vol 22 (S1) ◽

pp. S106-S106

Author(s):

K. de Wit ◽

S. Zarabi ◽

T. Chan ◽

F. Germini ◽

S. Mondoux ◽

...

Keyword(s):

Emergency Department ◽

Pulmonary Embolism ◽

Qualitative Interviews ◽

Theoretical Domains Framework ◽

Ct Scanning ◽

Evidence Based ◽

Novel Approach ◽

Wells Score ◽

And Function ◽

D Dimer

Background: Emergency physicians (EPs) can choose from several evidence-based pathways to diagnose pulmonary embolism (PE), however literature suggests that EPs frequently use computer tomography (CT) scanning as a stand-alone test for PE. This is a program of research to improve adherence to evidence-based PE diagnosis in the emergency department (ED). Aim Statement: To create a novel approach to PE diagnosis in the ED based on a framework explaining EP diagnostic PE behaviour and barriers to using evidence-based PE testing. Measures & Design: We conducted two types of qualitative interviews: 1). EPs in 5 Canadian cities watched videos of 2 simulated cases and then explained how they would test the patient. 2). Semi-structured EP interviews using the theoretical domains framework (TDF). The results of our analyses informed the construction of an explanatory framework for common EP diagnostic PE behaviours. Barriers to evidence-based behaviour were classified into domains. A Canadian EP expert group reviewed these results along with the existing evidence on ED PE diagnostic implementation. We developed a new approach to diagnosis of PE in the ED which addresses each of our domains. Evaluation/Results: We conducted 71 interviews. We identified 4 domains, each addressed in our pathway. ‘PE in a mythical and deadly beast’ PE kills and can masquerade so EPs look for PE in places where it does not exist and are rewarded for ‘over-testing’. Response: Creating a departmental conversation about missing PE, talking about the facts, busting the myths. EP feedback on PE testing including positive rate. ‘The end goal is CTPE’ PE creates anxiety for EPs and ordering a CTPE hands over responsibility to the radiologist. Response: A departmental protocol for PE testing which starts with D-dimer for every patient. Shifting focus to ruling out PE with D-dimer. Protocol is automated once initiated by EP. ‘PERC eases anxiety’ PERC is documented when it is negative and allows EP to stop. Response: EPs can choose to use and document PERC. ‘No-one has been fighting for the Wells score’ Poor understanding of purpose and function. Often at odds to Gestalt. Response: Protocol does not use Wells score. Discussion/Impact: We have developed a new diagnostic PE pathway which addresses current barriers to evidence-based practice which we will evaluate further.

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Safety and Clinical Utility of Four Clinical Decision Rules In the Diagnostic Management of Acute Pulmonary Embolism – the Prometheus Diagnosis Study

Blood ◽

10.1182/blood.v116.21.3186.3186 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3186-3186

Author(s):

Inge CM Mos ◽

Renée A Douma ◽

Petra MG Erkens ◽

Tessa AC Nizet ◽

Marc F Durian ◽

...

Keyword(s):

Pulmonary Embolism ◽

Clinical Utility ◽

Acute Pulmonary Embolism ◽

Decision Rules ◽

Clinical Decision ◽

Clinical Decision Rules ◽

Wells Rule ◽

Revised Geneva Score ◽

Acute Pe ◽

D Dimer

Abstract Abstract 3186 Background Several clinical decision rules (CDRs) are available for the exclusion of acute pulmonary embolism (PE). This prospective multi-center study compared the safety and clinical utility of four CDRs (Wells rule, revised Geneva score, simplified Wells rule and simplified revised Geneva score) in excluding PE in combination with D-dimer testing. Methods Clinical probability of patients with suspected acute PE was assessed using a computerized based “black box”, which calculated all CDRs and indicated the next diagnostic step. A “PE unlikely” result according to all CDRs in combination with a normal D-dimer result excluded PE, while patients with “PE likely” according to at least one of the CDRs or an abnormal D-dimer result underwent CT-scanning. Patients in whom PE was excluded were followed for three months. Results 807 consecutive patients were included and PE prevalence was 23%. The number of patients categorized as “PE unlikely” ranged from 62% (simplified Wells rule) to 72% (Wells rule). Combined with a normal D-dimer level, the CDRs excluded PE in 22–24% of patients. The total failure rates of the CDR-D-dimer combinations were similar (1 failure, 0.5– 0.6%, upper 95% CI 2.9– 3.1%). Despite 30% of the patients had discordant CDR outcomes, PE was missed in none of the patients with discordant CDRs and a normal D-dimer result. Conclusions All four CDRs show similar safety and clinical utility for exclusion of acute PE in combination with a normal D-dimer level. With this prospective validation, the more straightforward simplified scores are ready for use in clinical practice. Disclosures: No relevant conflicts of interest to declare.

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The Performance of the Original and Simplified Wells Scores in Combination with Age-Adjusted D-Dimer Testing in the Diagnostic Management of Pulmonary Embolism

Blood ◽

10.1182/blood.v128.22.2569.2569 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2569-2569

Author(s):

Noémie Kraaijpoel ◽

Nick van Es ◽

Harry R Büller ◽

Frederikus A Klok ◽

Menno V Huisman ◽

...

Keyword(s):

Pulmonary Embolism ◽

Failure Rate ◽

Meta Analysis ◽

Ease Of Use ◽

Grant Support ◽

Diagnostic Management ◽

Wells Score ◽

Wells Rule ◽

Discriminatory Performance ◽

D Dimer

Abstract Background: Among patients with suspected pulmonary embolism (PE), imaging can be safely withheld in those with a 'PE unlikely' Wells score and a negative D-dimer. A simplification of the Wells score has been proposed to improve clinical applicability (Table 1), but its performance is less clear, in particular in combination with age-adjusted D-dimer testing. Objectives: To compare the performance of the original and simplified Wells scores alone and in combination with age-adjusted D-dimer testing. Methods: Individual patient data from 7,268 patients with clinically suspected PE enrolled in 6 prospective diagnostic management studies were used. The discriminatory performance, calibration, and diagnostic accuracy of the original and simplified Wells scores were evaluated. The efficiency and failure rate of both dichotomized scores combined with age-adjusted D-dimer testing were compared using a one-stage random effects meta-analysis. Efficiency was defined as the proportion of patients in whom PE could be considered excluded based on a 'PE unlikely' Wells score and a D-dimer below the age-adjusted treshold, defined as ≤500 µg/L in patients of 50 years or younger and the patient's age times 10 µg/L in those older than 50 years. The failure rate was defined as the proportion of patients subsequently diagnosed with symptomatic venous thromboembolism during 3-month follow-up. Results: The discriminatory performance of the original and simplified Wells scores was comparable (c-statistic 0.73 [95% CI 0.72-0.75] vs. 0.72 [95% CI 0.70-0.73]). When combined with age-adjusted D-dimer testing, the original and simplified Wells rules had comparable efficiency (33% [95% CI 25-42%] vs 30% [95% CI 21-40%]) and failure rates (0.9% [95% CI 0.6-1.5%] vs. 0.8% [95% CI 0.5-1.3%]). Conclusion: Among patients with suspected PE, the original and simplified Wells rules in combination with age-adjusted D-dimer testing have similar performance in ruling out the disease. Given its ease of use in clinical practice, the simplified Wells rule may be preferred. Disclosures Huisman: Boehringer Ingelheim Pharma GmbH & Co.KG: Other: Grant support; GlaxoSmithKline: Other: Grant support; Bayer HealthCare: Other: Grant support; Pfizer: Other: Grant support; Actelion: Other: Grant support.

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Atrial fibrillation, an obscured cause of pulmonary embolism can be revealed by adding to Wells criteria

Journal of Investigative Medicine ◽

10.1136/jim-2018-000914 ◽

2019 ◽

Vol 67 (7) ◽

pp. 1042-1047

Author(s):

Canan Hasanoğlu ◽

Emine Argüder ◽

Hatice Kılıç ◽

Ebru Sengul Parlak ◽

Ayşegül Karalezli

Keyword(s):

Atrial Fibrillation ◽

Emergency Department ◽

Pulmonary Embolism ◽

Risk Factor ◽

Prospective Study ◽

Venous Thrombosis ◽

False Negative ◽

Scoring Methods ◽

Wells Score ◽

Clinical Scoring

Among the various clinical scoring methods used for the prediagnosis of pulmonary embolism (PE), Wells criteria is the most common. It relies on the findings and story of deep venous thrombosis (DVT), PE and malignancy. It is known that atrial fibrillation (AF) is a risk factor for PE like as DVT or malignancy. We aimed to evaluate the possibility of diagnosing more patients with PE by including AF in the Wells criteria. This prospective study included 250 patients admitted to the emergency department with PE findings. Wells scoring and Wells scoring with AF were performed for each patient. Out of 250 patients, 165 patients were diagnosed as PE. Wells score was >4 in 61.8% of patients with PE and 28.2% of patients without PE. Out of false negative 63 patients with PE, 21 of them had AF. According to Wells scoring with AF the score of 148 (89.7%) patients with PE diagnosis was ≥3, whereas the score of 45 (52.9%) patients without PE was ≥3. AF was detected in 15.8% of patients with PE. The sensitivity of Wells score with AF was significantly higher than that of the Wells score (p<0.001). As a result, when AF, which is one of an important PE cause such as DVT and malignancy, was added to the Wells criteria, an additional correct PE estimate was obtained in 46 patients. We recommend using Wells score with AF since prediagnosing more PE is more valuable than having some false negative PE predictions.

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Safety and Efficiency of the YEARS Diagnostic Algorithm for Pregnant Patients with Clinically Suspected Acute Pulmonary Embolism —the Artemis Study

Blood ◽

10.1182/blood-2018-99-113336 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 419-419

Author(s):

Liselotte M. Van Der Pol ◽

Cecile Tromeur ◽

Ingrid Bistervels ◽

Thomas van Bemmel ◽

Francis Couturaud ◽

...

Keyword(s):

Pulmonary Embolism ◽

Pregnant Women ◽

Failure Rate ◽

Acute Pulmonary Embolism ◽

Diagnostic Algorithm ◽

Ct Scanning ◽

Ct Scans ◽

Acute Pe ◽

D Dimer

Abstract Background Acute pulmonary embolism (PE) is the leading cause of maternal mortality in Western countries, accounting for 20 to 30% of all maternal deaths. Therefore, the threshold to test for PE during pregnancy is low. Because evidence regarding the safety of ruling out PE with clinical decision rules and D-dimer tests in pregnant women is unavailable, all women with a suspected PE need to undergo an imaging test, with potential harm to patient and fetus by exposure to ionizing radiation. In the present international, multicenter, prospective management study, we evaluated the safety and efficiency of the YEARS diagnostic algorithm for ruling out PE in pregnant patients with clinically suspected PE (Netherlands Trial Registry number 5913). YEARS is a simple diagnostic algorithm designed to reduce the number of required computed tomography (CT) scans in the diagnostic work-up of PE in non-pregnant patients, and was recently shown to be as safe as conventional algorithms but associated with a significant absolute 14% reduction in the number of CT scans (van der Hulle et al., Lancet 2017). Methods The Artemis study was performed in 11 Dutch hospitals, 8 French hospitals and 1 Irish hospital. Consecutive pregnant patients with suspected acute PE were included. Exclusion criteria were treatment with therapeutically dosed anticoagulants >24 hours or contraindications for CT. The YEARS algorithm was slightly adjusted for application during pregnancy (figure 1): in patients with signs of deep vein thrombosis (DVT), compression ultrasonography was obligatory before CT scanning was considered. In patients with proven DVT, anticoagulant treatment was initiated and no further diagnostic tests were undertaken. In patients with no YEARS items (Figure 1), a D-dimer threshold of <1.0 µg/ml was sufficient to rule out PE. In the remaining patients D-dimer threshold was <0.5 µg/mL. CT scanning was only performed in patients with a D-dimer level above the threshold. Anticoagulant therapy was withheld if PE was excluded. The primary safety endpoint was the occurrence of symptomatic venous thromboembolism during 3 months of follow-up, the primary efficiency endpoint was the proportion of patients in whom CTPA could be avoided. All safety endpoints were adjudicated by an independent committee. Assuming a 1.0% diagnostic failure rate and defining a maximum acceptable failure rate of 2.7%, a total study population of 472 patients was required (one-sided alpha 0.05, beta 80%). Results and conclusion: The last patient was included in May 2018. At baseline, 48% of pregnant women with suspected acute PE had no YEARS item and a D-dimer threshold of 1.0 µg/mL was applied. A total of 42% had a D-dimer level below the relevant threshold and were managed without CT scanning. Follow-up and endpoint adjudication was not completed at the abstract submission deadline; full study results will be presented at the ASH meeting. Disclosures Couturaud: Pfizer: Research Funding; Bayer: Honoraria, Other: Travel Support; AstraZeneca: Honoraria; Actelion: Other: Travel Support; Intermune: Other: Travel Support; Leo Pharma: Other: Travel Support; Daiichi Sankyo: Other: Travel Support.

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LO01: Prevalence of pulmonary embolism among Canadian emergency department patients with syncope: a multicenter prospective cohort study

CJEM ◽

10.1017/cem.2017.63 ◽

2017 ◽

Vol 19 (S1) ◽

pp. S27

Author(s):

V. Thiruganasambandamoorthy ◽

M. Sivilotti ◽

A. McRae ◽

M.A. Mukarram ◽

S. Kim ◽

...

Keyword(s):

Emergency Department ◽

Pulmonary Embolism ◽

Cross Sectional Study ◽

Study Cohort ◽

Cross Sectional ◽

Wells Score ◽

Emergency Department Patients ◽

Multicenter Prospective Cohort Study ◽

Work Up ◽

D Dimer

Introduction: A recent cross-sectional study reported a 17.3% prevalence of pulmonary embolism (PE) among patients with syncope. However, the study had several flaws including spectrum and work-up bias with over-diagnosis due to excessive investigations. We sought to evaluate the prevalence of PE among Canadian emergency department (ED) patients presenting with syncope. Methods: We enrolled adults with syncope at 5 EDs and collected demographics, proportion of patients evaluated for suspected PE, their Wells PE score values and results of investigations [d-dimer, computed angiography (CT) of chest or ventilation-perfusion (VQ) scan]. 30-day adjudicated outcome included diagnosis of PE requiring treatment. We used descriptive statistics to report the results. Results: 4,739 patients [mean age 54.3 years, 54.4% females, and 587 (12.4%) hospitalized] were enrolled. 323 patients (6.8%) had further evaluation and investigations performed for suspected PE: 255 patients had D-dimer performed, 140 had CT chest and 17 had VQ performed. Of the 323 patients, 300 patients were low risk (Wells score ≤4) and 23 were high-risk (score >4). A total of 16 patients (0.3%) in the study cohort were diagnosed with PE: 10 patients were diagnosed in the ED, 5 patients were diagnosed while hospitalized as inpatient, and 1 patient was diagnosed on a return ED visit. Overall the prevalence of PE was 0.3% among all ED patients with syncope; and a 0.9% among those hospitalized for syncope. Conclusion: Our study shows that the prevalence of PE is very low among all patients presenting to the ED with syncope. The prevalence is also very low among those hospitalized for syncope than previously reported. While PE should be suspected and further investigations performed among syncope patients if clinically appropriate, caution should also be taken against indiscriminate over-investigations for PE.

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