Pulmonary Embolism Rule-out Criteria Research Articles

Computed tomography pulmonary angiogram ordering, adherence to decision rules and yield in the emergency department: An observational study.

Pulmonary embolism (PE) frequently requires diagnosis through CT pulmonary angiogram (CTPA). Appropriate application of evidence-based clinical decision tools can reduce unnecessary CTPAs. This study assessed adherence to and the efficacy of various aspects of the Queensland Health suspected PE diagnostic pathway, including Wells score, PE rule out criteria (PERC) and age-adjusted D-dimer interpretation. Retrospective study of CTPAs ordered from 1 January to 30 April 2023 in a tertiary and urban ED in Southeast Queensland. Data on clinical variables, D-dimer and CTPA results were collected through medical record and radiology database review. Descriptive analyses were used to determine adherence to Queensland guidelines and performance of D-dimer interpretation tools (including comparison of age-adjusted PE with a new pre-test probability [PTP]-based model using D-dimer cut-off <1000 ng/mL for Wells score ≤4 and 500 ng/mL for Wells score 4.5-6). A total of 573 CTPAs were available for analysis with a 12.4% (95% confidence interval 10.0-15.4) diagnostic yield. Stratification by Wells score showed yields of 4.0%, 18.5% and 41% for low-, moderate- and high-risk patients, respectively. Twenty-five patients with low-PTP who received CTPA could have been excluded with the PERC rule. Age-adjusted D-dimer interpretation may have prevented 26 CTPAs with no false negatives, whereas PTP approach may have prevented 128 CTPAs with four false negatives. Guideline adherence can be improved, and adherence to existing clinical decision tools may reduce unnecessary CTPA ordering and increase diagnostic yield. The use of the age-adjusted D-dimer had good sensitivity, whereas the new PTP approach will require further prospective research.

Contemporary approaches to Pulmonary Embolism Diagnosis - a clinical review.

The optimal diagnosis strategy for pulmonary embolism (PE) in the emergency department (ED) remains complex. This review summarizes PE diagnosis with clinical presentation, decision rules and investigations for acute PE. This review was performed using studies published between January 1, 2010, and September 1, 2023. PE should be considered in ED in patients with chest pain, shortness of breath, syncope or signs of deep veinous thrombosis. Definitive diagnosis of PE relies on thoracic imaging, with the use of CTPA or ventilation/perfusion lung scintigraphy. To limit the continuous increased use of chest imaging, the clinical probability should be the first step for PE work out. The Pulmonary Embolism Rule-out Criteria (PERC rule) can rule out PE at this stage. If not, for low or intermediate probability, several clinical decision rules (CDR) have been validated, either by ruling out PE on clinical signs, or by raising D-Dimer thresholds (YEARS or PEGeD) or by combination of these different rules. It is recommended that patients with a high clinical probability of PE should undergo chest imaging without the need for D-dimer testing. The PE diagnostic approach can be tailored in specific populations such as pregnant, younger, COVID-19, or cancer patients. PE diagnosis workout illustrates the complexity of modern probabilistic-based approaches of decision-making in medicine. It is recommended to use a Bayesian approach with the evaluation of clinical probability, then order D-Dimer if the PERC rule is positive, then adapt the D-Dimer threshold for ordering chest imaging using CDR.

Analysis of predictive factors in children with high suspicion of pulmonary embolism.

Since there is a limited number of predictive models designed for pediatric patients with pulmonary embolism (PE), healthcare providers have resorted to utilizing the Wells criteria and PE Rule-out Criteria (PERC) that have been validated for use in adults. The objective of the study is to identify the predictive factors for PE and assess the effectiveness of the PERC, Wells, and pediatric-specific PE (PPE) criteria. The study included individuals between the ages of 0-18 years who underwent pulmonary CT angiography and/or ventilation-perfusion scintigraphy with suspicion of PE. Demographic characteristics, symptoms, physical examination findings, risk factors, and laboratory and imaging results were retrospectively analyzed, and PERC, Wells, and PPE criteria were applied to the study population. Of the 110 patients included in the study, 27 (24.5%) had PE. Saturation, albumin, cough, calf swelling, central catheter, and malignancy were found to significantly contribute to the model. The total weighted risk score, which represents the sum of all predictive scores, ranged from 0 to 16 with a mean of 5.41 ± 4.02. When the cut-off >6.5, the model had good discrimination power for positive PE (AUC 0.79, 77% sensitivity, and 70% specificity). In our study, the Wells criteria showed a sensitivity of 96% and a specificity of 24%. The PERCexhibited a sensitivity of 96% and a specificity of 21%, while the PPE demonstrated a sensitivity of 74% and a specificity of 30%. While the sensitivity of Wells, PERC, and PPE models was higher than our developed model, their specificities were considerably lower than our model.

Safety of the Pulmonary Embolism Rule-Out Criteria Rule: Findings from the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) Registry.

The diagnostic strategy for pulmonary embolism (PE) includes a D-dimer test when PE probability is low or intermediate, but false positive D-dimer results are frequent and can result in an unnecessary computed tomography pulmonary angiogram. The PE rule-out criteria (PERC) rule excludes PE without D-dimer testing when pre-test probability is <15%. The aim of this study was to assess the safety of the PERC rule strategy in patients included in the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) registry. This retrospective cohort study used data from the RIETE registry, an ongoing, international prospective registry of patients with objectively confirmed venous thromboembolism. The primary outcome was the failure rate of the PERC strategy, represented by the proportion of PERC-negative (PERC-N) patients with a PE included in the registry. Secondary outcomes were a comparison of the clinical characteristics, treatment strategy, and outcome of PERC-N versus PERC-positive (PERC-P) patients at 3 months. From 2001 to 2021, 49,793 patients with acute PE were enrolled in the RIETE registry. We included 48,903 in the final analysis after exclusion of 890 patients with an undetermined PERC status. Only 346 patients were PERC-N with a failure rate of 0.7% (95% confidence interval 0.6-0.8%). PERC-N patients presented more frequently with chest pain, but less often with dyspnea, syncope or hypotension. They had also sub-segmental or segmental PE more frequently, were more often treated with direct oral anticoagulants, and received mechanical or pharmacological thrombolysis less often. In addition, PERC-N patients had a lower incidence of recurrent deep vein thrombosis, major bleeding, and death attributed to PE during the 3-month follow-up. A low failure rate of the PERC rule was observed in the RIETE registry, thus supporting its use to safely identify patients with an unlikely probability of PE.

Bedside exclusion of pulmonary embolism in children without radiation (BEEPER): a national study of the Pediatric Emergency Care Applied Research Network—Study protocol

BackgroundThe Pulmonary Embolism Rule Out Criteria (PERC) Peds rule, derived from the PERC rule, was derived to estimate a low pretest probability for pulmonary embolism (PE) in children but has not been prospectively validated. ObjectiveThe objective of this study was to present a protocol for an ongoing multicenter prospective observational study that evaluates the diagnostic accuracy of the PERC-Peds rule. MethodsThis protocol is identified by the acronym, BEdside Exclusion of Pulmonary Embolism without Radiation in children. The study aims were designed to prospectively validate, or if necessary, refine, the accuracy of PERC-Peds and D-dimer in excluding PE among children with clinical suspicion or testing for PE. Multiple ancillary studies will examine clinical characteristics and epidemiology of the participants. Children aged 4 through 17 years were being enrolled at 21 sites through the Pediatric Emergency Care Applied Research Network (PECARN). Patients taking anticoagulant therapy are excluded. PERC-Peds criteria data, clinical gestalt, and demographic information are collected in real time. The criterion standard outcome is image-confirmed venous thromboembolism within 45 days, determined from independent expert adjudication. We assessed interrater reliability of the PERC-Peds, frequency of PERC-Peds use in routine clinical care, and descriptive characteristics of missed eligible and missed patients with PE. ResultsEnrollment is currently 60% complete with an anticipated data lock in 2025. ConclusionsThis prospective multicenter observational study will not only test whether a set of simple criteria can safely exclude PE without need for imaging but also provide a resource to fill a critical knowledge gap about clinical characteristics of children with suspected and diagnosed PE.

Revision of Clinical Pre-Test Probability Scores in Hospitalized Patients with Pulmonary Embolism and SARS-CoV-2 Infection

Background: The need for computed tomography pulmonary angiography (CTPA) to rule out pulmonary embolism (PE) is based on clinical scores in association with D-dimer measurements. PE is a recognized complication in patients with SARS-CoV-2 infection due to a pro-thrombotic state which may reduce the usefulness of preexisting pre-test probability scores. Aim: The purpose was to analyze new clinical and laboratory parameters while comparing existing and newly proposed scoring system for PE detection in hospitalized COVID-19 patients (HCP). Methods: We conducted a retrospective study of 270 consecutive HCPs who underwent CTPA due to suspected PE. The Modified Wells, Revised Geneva, Simplified Geneva, YEARS, 4-Level Pulmonary Embolism Clinical Probability Score (4PEPS), and PE rule-out criteria (PERC) scores were calculated and the area under the receiver operating characteristic curve (AuROC) was measured. Results: Overall incidence of PE among our study group of HCPs was 28.1%. The group of patients with PE had a significantly longer COVID-19 duration upon admission, at 10 vs 8 days, p = 0.006; higher D-dimer levels of 10.2 vs 5.3 μg/L, p &lt; 0.001; and a larger proportion of underlying chronic kidney disease, at 16% vs 7%, p = 0.041. From already established scores, only 4PEPS and the modified Wells score reached statistical significance in detecting the difference between the HCP groups with or without PE. We proposed a new chronic kidney disease, D-dimers, 10 days of illness before admission (CDD-10) score consisting of the three aforementioned variables: C as chronic kidney disease (0.5 points if present), D as D-dimers (negative 1.5 points if normal, 2 points if over 10.0 μg/L), and D-10 as day-10 of illness carrying 2 points if lasting more than 10 days before admission or 1 point if longer than 8 days. The CDD-10 score ranged from –1.5 to 4.5 and had an AuROC of 0.672, p &lt; 0.001 at cutoff value at 0.5 while 4PEPS score had an AuROC of 0.638 and Modified Wells score 0.611. The clinical probability of PE was low (0%) when the CDD-10 value was negative, moderate (24%) for CDD-10 ranging 0–2.5 and high (43%) when over 2.5. Conclusions: Better risk stratification is needed for HCPs who require CTPA for suspected PE. Our newly proposed CDD-10 score demonstrates the best accuracy in predicting PE in patients hospitalized for SARS-CoV-2 infection.

Current Diagnosis and Management of Acute Pulmonary Embolism: A Strategy for General Practitioners in Emergency Department.

Pulmonary embolism (PE) is a disease with a relatively good prognosis when diagnosed and treated properly. This review aims to analyse available data and combine them into algorithms that physicians can use in the emergency department for quick decision-making in diagnosing and treating PE. The available data show that PE can be excluded through highly sensitive clinical decision rules, i.e. Pulmonary Embolism Rule-Out Criteria (PERC), Wells criteria, and Revised Geneva criteria, combined with D-dimer assessment. In cases where PE could not be excluded through the mentioned strategies, imaging modalities, such as compression ultrasonography (CUS), computed tomographic pulmonary angiography (CTPA), and planar ventilation/perfusion (V/Q) scan, are indicated for a definite diagnosis. Once a diagnosis has been made, treatment of PE depends on its mortality risk as patients are divided into low-, intermediate-, and high-risk cases. High-risk cases are treated for their hemodynamic instability, given parenteral or oral anticoagulant therapy, and are indicated for reperfusion therapy. Intermediate-risk PE is only given parenteral or oral anticoagulants and reperfusion is indicated when anticoagulants fail. Low-risk cases are given oral anticoagulants and based on the Hestia criteria, patients may be discharged and treated as outpatients.

Aplicação dos critérios PERC e do D-Dímero ajustado para idade em pacientes submetidos a angiotomografia pulmonar para o diagnóstico de embolia pulmonar

Diagnosis of pulmonary embolism (PE) constitutes a challenge for practitioners. Current practice involves use of pre-test probability prediction rules. Several strategies to optimize this process have been explored. To explore whether application of the pulmonary embolism rule-out criteria (PERC rule) and age-adjusted D-dimer (DD) would have reduced the number of computed tomography pulmonary angiography (CTPA) examinations performed in patients with suspected PE. A retrospective cross-sectional study of adult patients taken for CTPA under suspicion of PE in 2018 and 2020. The PERC rule and age-adjusted DD were applied. The number of cases without indications for imaging studies was estimated and the operational characteristics for diagnosis of PE were calculated. 302 patients were included. PE was diagnosed in 29.8%. Only 27.2% of 'not probable' cases according to the Wells criteria had D-dimer assays. Age adjustment would have reduced tomography use by 11.1%, with an AUC of 0.5. The PERC rule would have reduced use by 7%, with an AUC of 0.72. Application of age-adjusted D-dimer and the PERC rule to patients taken for CTPA because of suspected PE seems to reduce the number of indications for the procedure.

VITALS ARE VITAL: AN UNUSUAL PRESENTATION OF PULMONARY EMBOLISM

SESSION TITLE: Pulmonary Vascular Disease Case PostersSESSION TYPE: Case Report PostersPRESENTED ON: 10/17/2022 12:15 pm - 01:15 pmINTRODUCTION: A pulmonary embolism (PE) represents a potentially life-threatening condition that may require immediate intervention. While many physicians recognize the classic presentation of tachycardia, tachypnea and chest pain, these are only present in 24-54% of patients and even fewer have all three (1,2). Therefore, it is important to maintain a high index of suspicion and recognize atypical presentations. Here we report a case of a patient presenting with severe epigastric abdominal pain that was found to have a PE.CASE PRESENTATION: A 56-year-old man with a history of COPD, HTN, previous MI and T2DM presented to the emergency department with sudden onset epigastric abdominal pain. His vital signs were notable for a respiratory rate of 28, heart rate of 120 and oxygen saturation of 98% on room air. His physical exam revealed epigastric tenderness. Labs revealed a WBC of 15, normal troponins and a lactate of 2.7. His venous blood gas was normal. His ECG was remarkable only for sinus tachycardia. His chest radiograph was unremarkable. A CT angiography of the abdomen/pelvis was obtained due to concern for bowel ischemia and was unremarkable. Due to the patient's tachycardia and tachypnea, a CT angiography of the chest was obtained and demonstrated a PE involving the right lateral basilar segmental artery. He was treated with oral anticoagulation.DISCUSSION: Many efforts have been made to generate a scoring system to guide the diagnosis of PE. The modified Wells criteria, PE rule out criteria (PERC) and revised Geneva score are widely used (3). A significant limitation of these systems is that a physician must first consider the diagnosis of PE before applying them. Therefore, while these tools attempt to limit the use of pure clinical gestalt in determining which patients to scan or obtain a d-dimer on, the first step in the diagnostic pathway is clinical suspicion. An additional limitation is discrepancy between scores. For example, our patient's modified Wells score was 1.5, placing him in the low-risk group (< 3% incidence of PE). On the other hand, his PERC score was 1, indicating PE could not be ruled out and his revised Geneva score was 5, indicating moderate-risk (20-30% incidence of PE).CONCLUSIONS: A PE is known as "the great masquerader” due to its ability to mimic a variety of diagnoses. While risk stratification tools such as the modified Wells score, PERC and revised Geneva score are helpful, it should be recognized that they are imperfect. In our patient, the unexplained tachypnea and tachycardia prompted concern for PE despite his low-risk Wells score. His abdominal pain was a red herring, but is an important reminder of the variability of symptoms that patients with a PE can present with. Ultimately, if a patient has unexplained vital signs derangements that are consistent with PE without other plausible explanations, PE should be considered.Reference #1: Stein, Paul D et al. "Clinical characteristics of patients with acute pulmonary embolism: data from PIOPED II.” The American journal of medicine vol. 120,10 (2007): 871-9. doi:10.1016/j.amjmed.2007.03.024Reference #2: Pollack, Charles V et al. "Clinical characteristics, management, and outcomes of patients diagnosed with acute pulmonary embolism in the emergency department: initial report of EMPEROR (Multicenter Emergency Medicine Pulmonary Embolism in the Real World Registry).” Journal of the American College of Cardiology vol. 57,6 (2011): 700-6. doi:10.1016/j.jacc.2010.05.071Reference #3: Tarbox, Abigail K, and Mamta Swaroop. "Pulmonary embolism.” International journal of critical illness and injury science vol. 3,1 (2013): 69-72. doi:10.4103/2229-5151.109427DISCLOSURES: No relevant relationships by Loor AlshawaNo relevant relationships by Andrew Rudnick SESSION TITLE: Pulmonary Vascular Disease Case Posters SESSION TYPE: Case Report Posters PRESENTED ON: 10/17/2022 12:15 pm - 01:15 pm INTRODUCTION: A pulmonary embolism (PE) represents a potentially life-threatening condition that may require immediate intervention. While many physicians recognize the classic presentation of tachycardia, tachypnea and chest pain, these are only present in 24-54% of patients and even fewer have all three (1,2). Therefore, it is important to maintain a high index of suspicion and recognize atypical presentations. Here we report a case of a patient presenting with severe epigastric abdominal pain that was found to have a PE. CASE PRESENTATION: A 56-year-old man with a history of COPD, HTN, previous MI and T2DM presented to the emergency department with sudden onset epigastric abdominal pain. His vital signs were notable for a respiratory rate of 28, heart rate of 120 and oxygen saturation of 98% on room air. His physical exam revealed epigastric tenderness. Labs revealed a WBC of 15, normal troponins and a lactate of 2.7. His venous blood gas was normal. His ECG was remarkable only for sinus tachycardia. His chest radiograph was unremarkable. A CT angiography of the abdomen/pelvis was obtained due to concern for bowel ischemia and was unremarkable. Due to the patient's tachycardia and tachypnea, a CT angiography of the chest was obtained and demonstrated a PE involving the right lateral basilar segmental artery. He was treated with oral anticoagulation. DISCUSSION: Many efforts have been made to generate a scoring system to guide the diagnosis of PE. The modified Wells criteria, PE rule out criteria (PERC) and revised Geneva score are widely used (3). A significant limitation of these systems is that a physician must first consider the diagnosis of PE before applying them. Therefore, while these tools attempt to limit the use of pure clinical gestalt in determining which patients to scan or obtain a d-dimer on, the first step in the diagnostic pathway is clinical suspicion. An additional limitation is discrepancy between scores. For example, our patient's modified Wells score was 1.5, placing him in the low-risk group (< 3% incidence of PE). On the other hand, his PERC score was 1, indicating PE could not be ruled out and his revised Geneva score was 5, indicating moderate-risk (20-30% incidence of PE). CONCLUSIONS: A PE is known as "the great masquerader” due to its ability to mimic a variety of diagnoses. While risk stratification tools such as the modified Wells score, PERC and revised Geneva score are helpful, it should be recognized that they are imperfect. In our patient, the unexplained tachypnea and tachycardia prompted concern for PE despite his low-risk Wells score. His abdominal pain was a red herring, but is an important reminder of the variability of symptoms that patients with a PE can present with. Ultimately, if a patient has unexplained vital signs derangements that are consistent with PE without other plausible explanations, PE should be considered. Reference #1: Stein, Paul D et al. "Clinical characteristics of patients with acute pulmonary embolism: data from PIOPED II.” The American journal of medicine vol. 120,10 (2007): 871-9. doi:10.1016/j.amjmed.2007.03.024 Reference #2: Pollack, Charles V et al. "Clinical characteristics, management, and outcomes of patients diagnosed with acute pulmonary embolism in the emergency department: initial report of EMPEROR (Multicenter Emergency Medicine Pulmonary Embolism in the Real World Registry).” Journal of the American College of Cardiology vol. 57,6 (2011): 700-6. doi:10.1016/j.jacc.2010.05.071 Reference #3: Tarbox, Abigail K, and Mamta Swaroop. "Pulmonary embolism.” International journal of critical illness and injury science vol. 3,1 (2013): 69-72. doi:10.4103/2229-5151.109427 DISCLOSURES: No relevant relationships by Loor Alshawa No relevant relationships by Andrew Rudnick

110 Pulmonary Embolism and Cancer – Can the PERC Rule Still Apply?

Pulmonary Embolism (PE) in cancer is a controversial topic, with experts in several fields at odds regarding prophylactic anticoagulation, predictive models, and risk stratification. The Wells and Geneva Scores both include cancer as a high risk condition, though alone, cancer does not place an individual in the high risk category. The Pulmonary Embolism Rule-out Criteria (PERC score) is an accepted decision rule for use in the emergency department (ED) on low-risk patients. Our objective was to evaluate the performance of the PERC rule when applied retrospectively to a cohort of ED patients who were ultimately diagnosed with PE.

The utility of risk assessment tools for acute pulmonary embolism in children.

The study consisted of patients under 18 years of age who were consulted to the Pediatric Pulmonology Clinic for the evaluation of PE. Patients were divided into two groups based on the confirmation of PE. The group with the presence of PE (n = 20) consisted of children who were diagnosed with PE. The group with the absence of PE (n = 28) consisted of children with clinically suspected PE but negative diagnostic imaging. Adult validated clinical decision PERC rule and Pediatric PE Model were retrospectively applied to the patients. In the study, PERC demonstrated a sensitivity of 60%and a specificity of 46% for the diagnosis of PE in children. When PE Model was evaluated for the children, it was found a 50% sensitivity and 75% specificity. Combining PE Model and PERC rule with D-dimer did not increase the specificity and sensitivity. Smoking was found to be relevant for PE in the childhood. Twenty-five percent of the patients had a genetic tendency for PE. All of the patients had an underlying disease as well. None of the current risk assessment tools (PE Model, PERC, D-dimer) were found to be accurate in predicting PE. Further larger population studies are still required to develop a better diagnostic approach.

Clinical predictors of pulmonary embolism for inpatients: are computed tomography pulmonary angiograms being requested appropriately?

The heterogeneity of inpatient pulmonary embolism (PE) presentations may lead to computed tomography pulmonary angiograms (CTPA) being over-requested. Current clinical predictors for PE, including Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC), have predominantly focussed on outpatient and emergency department populations. To determine the clinical indicators for ordering inpatient CTPA and the predictors of positive scans for PE. Consecutive inpatient CTPA (performed >24 h after admission) from January 2017 to December 2017 were retrospectively reviewed. Variables including baseline characteristics, vital signs and risk factors for PE were extracted. A total of 312 CTPA was reviewed (average patient age 67 years; 46% male) and 36 CTPA were positive for PE (11.5%). The average time to inpatient CTPA request was 7 days. Clinical indicators associated with positive scans were hypoxia (odds ratio (OR) 2.4; 95% confidence interval (CI) 1.1-5.6), tachypnoea (OR 2.5; 95% CI 1.2-6.0), recent surgery or immobilisation (OR 2.7; 95% CI 1.2-6.4), S1Q3T3 pattern on electrocardiogram (ECG; OR 7.2; 95% CI 1.4-35.7) and right bundle branch block pattern on ECG (OR 4.7; 95% CI 1.6-13.1). Hypotension, fever and malignancy were not significant. Both PERC and Wells criteria had poor positive predictive value (12% and 27% respectively), but the negative predictive value for PERC and Wells was 100% and 95.8% respectively. Inpatient CTPA appear to be over-requested and can potentially be rationalised based on a combination of clinical predictors and Wells criteria and/or PERC rule. Further prospective studies are needed to develop accurate clinical decision tools targeted towards inpatients.

Comparison of the safety and efficacy of YEARS, PEGeD, 4PEPS or the sole item "PE is the most likely diagnosis" strategies for the diagnosis of pulmonary embolism in the emergency department: post-hoc analysis of two European cohort studies.

The optimal strategy for the diagnosis of pulmonary embolism (PE) in the emergency department (ED) remains debated. To reduce the need of imaging testing, several rules have been recently validated using an elevated D-dimer threshold. To validate the safety of different diagnostic strategies and compare the efficacy in terms of chest imaging testing. Post-hoc analysis of individual data of 3330 adult patients without a high clinical probability of PE in the ED followed-up at 3 months in France and Spain (1916 from the PROPER cohort, 1414 from the MODIGLIANI cohort). Four diagnostic strategies with an elevated D-dimer threshold if PE is unlikely. The YEARS combined with Pulmonary Embolism Rule-out Criteria (PERC) the pulmonary embolism graduated D-dimer (PEGeD) combined with PERC and the 4-level pulmonary embolism probability score (4PEPS) rules were assessed. A modified simplified (MODS) rule with a simplified YEARS reduced to the sole item of "Is PE the most likely diagnosis" combined with PERC was also tested. The primary outcome was the proportion of diagnosed PE or deep venous thrombosis at 3 months in patients in whom PE could have been excluded without chest imaging according to the tested strategy. The safety of a strategy was confirmed if the failure rate was less than 1.85%. The secondary outcome was the use of imaging testing according to each rule. Among 3330 analyzed patients, 150 (4.5%) had a PE. The number of missed PEs were 25, 29, 30 and 26 for the PERC+YEARS, PERC+PEGeD, 4PEPS and MODS rules respectively, with a failure rate of 0.75% (95% CI 0.51% to 1.10%), 0.87% (0.61% to 1.25%), 0.90% (0.63% to 1.28%) and 0.78% (0.53% to 1.14%) respectively. There was no significant difference in the failure rate between rules. Except for a significant lower use of chest imaging for 4PEPS compared to YEARS (14.9% vs 16.3%, difference -1.4% [95%CI -2.1% to -0.8%]), there was no difference in the proportion of imaging testing. In this post-hoc analysis of patients with suspicion of PE, YEARS and PEGeD combined with PERC, and 4PEPS were safe to exclude PE. The safety of the modified simplified MODS strategy was also confirmed. There was no significant difference of the failure rate between strategies.

[Translated article] Multidisciplinary consensus for the management of pulmonary thromboembolism

We have updated recommendations on 12 controversial topics that were published in the 2013 National Consensus on the diagnosis, risk stratification and treatment of patients with pulmonary embolism (PE). A comprehensive review of the literature was performed for each topic, and each recommendation was evaluated in two teleconferences. For diagnosis, we recommend against using the Pulmonary Embolism Rule Out Criteria (PERC) rule as the only test to rule out PE, and we recommend using a d-dimer cutoff adjusted to age to rule out PE. We suggest using computed tomography pulmonary angiogram as the imaging test of choice for the majority of patients with suspected PE. We recommend using direct oral anticoagulants (over vitamin K antagonists) for the vast majority of patients with acute PE, and we suggest using anticoagulation for patients with isolated subsegmental PE. We recommend against inserting an inferior cava filter for the majority of patients with PE, and we recommend using full-dose systemic thrombolytic therapy for PE patients requiring reperfusion. The decision to stop anticoagulants at 3 months or to treat indefinitely mainly depends on the presence (or absence) and type of risk factor for venous thromboembolism, and we recommend against thrombophilia testing to decide duration of anticoagulation. Finally, we suggest against extensive screening for occult cancer in patients with PE.

Performance of Prehospital Use of Chest Pain Risk Stratification Tools: The RESCUE Study

Background Emergency medical services (EMS) assesses millions of patients with chest pain each year. However, tools validated to risk stratify patients for acute coronary syndrome (ACS) and pulmonary embolism (PE) have not been translated to the prehospital setting. The objective of this study is to assess the prehospital performance of risk stratification scores for 30-day major adverse cardiac events (MACE) and PE. Methods A prospective observational cohort study of patients ≥21 years of age with acute chest pain who were transported by EMS in two North Carolina (NC) counties was conducted from 18 April 2018–2 January 2019. In this convenience sample, paramedics completed HEAR (history, electrocardiogram, age, risk factor), ED Assessment of Chest Pain Score (EDACS), Revised Geneva Score (RGS), and pulmonary embolism rule-out criteria (PERC) assessments on each patient. MACE (all-cause death, myocardial infarction, and revascularization) and PE at 30 days were determined by hospital records and NC Death Index. The positive (+LR) and negative likelihood ratios (−LR) of the risk scores for 30-day MACE and PE were calculated. Results During the study period, 82.1% (687/837) patients had all four risk score assessments. The cohort was 51.1% (351/687) female, 49.5% (340/687) African American, and had a mean age of 55.0 years (SD 16.0). At 30 days, MACE occurred in 7.4% (51/687), PE occurred in 0.9% (6/687), and the combined outcome occurred in 8.2% (56/687). The HEAR score had a − LR of 0.46 (95% CI 0.27–0.78) and + LR of 1.48 (95% CI 1.26–1.74) for 30-day MACE. EDACS had a − LR of 0.61 (95% CI 0.46–0.81) and + LR of 2.53 (95% CI 1.86–3.46) for 30-day MACE. The PERC score had a − LR of 0 (95% CI 0.0–1.4) and a + LR of 1.38 (95% CI 1.32–1.45) for 30-day PE. The RGS score had a − LR of 0 (95% CI 0.0–0.65) and a + LR of 2.36 (95% CI 2.16–2.57) for 30-day PE. The combination of a low-risk HEAR score and negative PERC evaluation had a − LR of 0.25 (95% CI 0.08–0.76) and a + LR of 1.21 (95% CI 1.21–1.30) for 30-day MACE or PE. Conclusion The combination of a paramedic-obtained HEAR score and PERC evaluation performed best to exclude 30-day MACE and PE but was not sufficient for directing prehospital decision making.

Ruling out pulmonary embolism across different healthcare settings: A systematic review and individual patient data meta-analysis

The challenging clinical dilemma of detecting pulmonary embolism (PE) in suspected patients is encountered in a variety of healthcare settings. We hypothesized that the optimal diagnostic approach to detect these patients in terms of safety and efficiency depends on underlying PE prevalence, case mix, and physician experience, overall reflected by the type of setting where patients are initially assessed. The objective of this study was to assess the capability of ruling out PE by available diagnostic strategies across all possible settings. We performed a literature search (MEDLINE) followed by an individual patient data (IPD) meta-analysis (MA; 23 studies), including patients from self-referral emergency care (n = 12,612), primary healthcare clinics (n = 3,174), referred secondary care (n = 17,052), and hospitalized or nursing home patients (n = 2,410). Multilevel logistic regression was performed to evaluate diagnostic performance of the Wells and revised Geneva rules, both using fixed and adapted D-dimer thresholds to age or pretest probability (PTP), for the YEARS algorithm and for the Pulmonary Embolism Rule-out Criteria (PERC). All strategies were tested separately in each healthcare setting. Following studies done in this field, the primary diagnostic metrices estimated from the models were the "failure rate" of each strategy-i.e., the proportion of missed PE among patients categorized as "PE excluded" and "efficiency"-defined as the proportion of patients categorized as "PE excluded" among all patients. In self-referral emergency care, the PERC algorithm excludes PE in 21% of suspected patients at a failure rate of 1.12% (95% confidence interval [CI] 0.74 to 1.70), whereas this increases to 6.01% (4.09 to 8.75) in referred patients to secondary care at an efficiency of 10%. In patients from primary healthcare and those referred to secondary care, strategies adjusting D-dimer to PTP are the most efficient (range: 43% to 62%) at a failure rate ranging between 0.25% and 3.06%, with higher failure rates observed in patients referred to secondary care. For this latter setting, strategies adjusting D-dimer to age are associated with a lower failure rate ranging between 0.65% and 0.81%, yet are also less efficient (range: 33% and 35%). For all strategies, failure rates are highest in hospitalized or nursing home patients, ranging between 1.68% and 5.13%, at an efficiency ranging between 15% and 30%. The main limitation of the primary analyses was that the diagnostic performance of each strategy was compared in different sets of studies since the availability of items used in each diagnostic strategy differed across included studies; however, sensitivity analyses suggested that the findings were robust. The capability of safely and efficiently ruling out PE of available diagnostic strategies differs for different healthcare settings. The findings of this IPD MA help in determining the optimum diagnostic strategies for ruling out PE per healthcare setting, balancing the trade-off between failure rate and efficiency of each strategy.

Prehospital Translation of Chest Pain Tools (RESCUE Study): Completion Rate and Inter-rater Reliability.

IntroductionChest pain is a common reason for ambulance transport. Acute coronary syndrome (ACS) and pulmonary embolism (PE) risk assessments, such as history, electrocardiogram, age, risk factors (HEAR); Emergency Department Assessment of Chest Pain Score (EDACS); Pulmonary Embolism Rule-out Criteria (PERC); and revised Geneva score, are well validated for emergency department (ED) use but have not been translated to the prehospital setting. The objectives of this study were to evaluate the 1) prehospital completion rate and 2) inter-rater reliability of chest pain risk assessments.MethodsWe conducted a prospective observational cohort study in two emergency medical services (EMS) agencies (April 18, 2018 – January 2, 2019). Adults with acute, non-traumatic chest pain without ST-elevation myocardial infarction or unstable vital signs were accrued. Paramedics were trained to use the HEAR, EDACS, PERC, and revised Geneva score assessments. A subset of patients (a priori goal of N = 250) also had the four risk assessments completed by their treating clinicians in the ED, who were blinded to the EMS risk assessments. Outcomes were 1) risk assessments completion rate and 2) inter-rater reliability between EMS and ED assessments. An a priori goal for completion rate was set as >75%. We computed kappa with corresponding 95% confidence intervals (CI) for each risk assessment as a measure of inter-rater reliability. Acceptable agreement was defined a priori as kappa ≥ 0.60.ResultsDuring the study period, 837 patients with acute chest pain were accrued. The median age was 54 years, interquartile range 43–66, with 53% female and 51% Black. Completion rates for each risk assessment were above goal: the HEAR score was completed on 95.1% (796/837), EDACS on 92.0% (770/837), PERC on 89.4% (748/837), and revised Geneva score on 90.7% (759/837) of patients. We assessed agreement in a subgroup of 260 patients. The HEAR score had a kappa of 0.51 (95% CI, 0.41–0.61); EDACS was 0.60 (95% CI, 0.49–0.72); PERC was 0.71 (95% CI, 0.61–0.81); and revised Geneva score was 0.51 (95% CI, 0.39–0.62).ConclusionThe completion rate of risk assessments for ACS and PE was high for prehospital field personnel. The PERC and EDACS both demonstrated acceptable agreement between paramedics and clinicians in the ED, although assessments with better agreement are likely needed.

Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism

Uncontrolled studies suggest that pulmonary embolism (PE) can be safely ruled out using the YEARS rule, a diagnostic strategy that uses varying D-dimer thresholds. To prospectively validate the safety of a strategy that combines the YEARS rule with the pulmonary embolism rule-out criteria (PERC) rule and an age-adjusted D-dimer threshold. A cluster-randomized, crossover, noninferiority trial in 18 emergency departments (EDs) in France and Spain. Patients (N = 1414) who had a low clinical risk of PE not excluded by the PERC rule or a subjective clinical intermediate risk of PE were included from October 2019 to June 2020, and followed up until October 2020. Each center was randomized for the sequence of intervention periods. In the intervention period (726 patients), PE was excluded without chest imaging in patients with no YEARS criteria and a D-dimer level less than 1000 ng/mL and in patients with 1 or more YEARS criteria and a D-dimer level less than the age-adjusted threshold (500 ng/mL if age <50 years or age in years × 10 in patients ≥50 years). In the control period (688 patients), PE was excluded without chest imaging if the D-dimer level was less than the age-adjusted threshold. The primary end point was venous thromboembolism (VTE) at 3 months. The noninferiority margin was set at 1.35%. There were 8 secondary end points, including chest imaging, ED length of stay, hospital admission, nonindicated anticoagulation treatment, all-cause death, and all-cause readmission at 3 months. Of the 1414 included patients (mean age, 55 years; 58% female), 1217 (86%) were analyzed in the per-protocol analysis. PE was diagnosed in the ED in 100 patients (7.1%). At 3 months, VTE was diagnosed in 1 patient in the intervention group (0.15% [95% CI, 0.0% to 0.86%]) vs 5 patients in the control group (0.80% [95% CI, 0.26% to 1.86%]) (adjusted difference, -0.64% [1-sided 97.5% CI, -∞ to 0.21%], within the noninferiority margin). Of the 6 analyzed secondary end points, only 2 showed a statistically significant difference in the intervention group compared with the control group: chest imaging (30.4% vs 40.0%; adjusted difference, -8.7% [95% CI, -13.8% to -3.5%]) and ED median length of stay (6 hours [IQR, 4 to 8 hours] vs 6 hours [IQR, 5 to 9 hours]; adjusted difference, -1.6 hours [95% CI, -2.3 to -0.9]). Among ED patients with suspected PE, the use of the YEARS rule combined with the age-adjusted D-dimer threshold in PERC-positive patients, compared with a conventional diagnostic strategy, did not result in an inferior rate of thromboembolic events. ClinicalTrials.gov Identifier: NCT04032769.

Development of a machine learning model using electrocardiogram signals to improve acute pulmonary embolism screening.

AimsClinical scoring systems for pulmonary embolism (PE) screening have low specificity and contribute to computed tomography pulmonary angiogram (CTPA) overuse. We assessed whether deep learning models using an existing and routinely collected data modality, electrocardiogram (ECG) waveforms, can increase specificity for PE detection.Methods and resultsWe create a retrospective cohort of 21 183 patients at moderate- to high suspicion of PE and associate 23 793 CTPAs (10.0% PE-positive) with 320 746 ECGs and encounter-level clinical data (demographics, comorbidities, vital signs, and labs). We develop three machine learning models to predict PE likelihood: an ECG model using only ECG waveform data, an EHR model using tabular clinical data, and a Fusion model integrating clinical data and an embedded representation of the ECG waveform. We find that a Fusion model [area under the receiver-operating characteristic curve (AUROC) 0.81 ± 0.01] outperforms both the ECG model (AUROC 0.59 ± 0.01) and EHR model (AUROC 0.65 ± 0.01). On a sample of 100 patients from the test set, the Fusion model also achieves greater specificity (0.18) and performance (AUROC 0.84 ± 0.01) than four commonly evaluated clinical scores: Wells’ Criteria, Revised Geneva Score, Pulmonary Embolism Rule-Out Criteria, and 4-Level Pulmonary Embolism Clinical Probability Score (AUROC 0.50–0.58, specificity 0.00–0.05). The model is superior to these scores on feature sensitivity analyses (AUROC 0.66–0.84) and achieves comparable performance across sex (AUROC 0.81) and racial/ethnic (AUROC 0.77–0.84) subgroups.ConclusionSynergistic deep learning of ECG waveforms with traditional clinical variables can increase the specificity of PE detection in patients at least at moderate suspicion for PE.

Machine learning with D-dimer in the risk stratification for pulmonary embolism: a derivation and internal validation study.

To develop a machine learning model to predict the diagnosis of pulmonary embolism (PE). We undertook a derivation and internal validation study to develop a risk prediction model for use in patients being investigated for possible PE. The machine learning technique, generalized logistic regression using elastic net, was chosen following an assessment of seven machine learning techniques and on the basis that it optimized the area under the receiver operator characteristic curve (AUC) and Brier score. Models were developed both with and without the addition of D-dimer. A total of 3347 patients were included in the study of whom, 219 (6.5%) had PE. Four clinical variables (O2 saturation, previous deep venous thrombosis or PE, immobilization or surgery, and alternative diagnosis equal or more likely than PE) plus D-dimer contributed to the machine learning models. The addition of D-dimer improved the AUC by 0.16 (95% confidence interval 0.13-0.19), from 0.73 to 0.89 (0.87-0.91) and decreased the Brier score by 14% (10-18%). More could be ruled out with a higher positive likelihood ratio than by the Wells score combined with D-dimer, revised Geneva score combined with D-dimer, or the Pulmonary Embolism Rule-out Criteria score. Machine learning with D-dimer maintained a low-false-negative rate at a true-negative rate of nearly 53%, which was better performance than any of the other alternatives. A machine learning model outperformed traditional risk scores for the risk stratification of PE in the emergency department. However, external validation is needed.