Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected pulmonary embolism

A case report of point-of-care ultrasound directed thrombectomy: a reversible cause of cardiac arrest managed with extracorporeal membrane oxygenation cannulation

Extracorporeal membrane oxygenation (ECMO) has been increasingly employed in the emergency department for patients with a potentially reversible cause of cardiac arrest. We present the case of a young female patient with an in-hospital cardiac arrest who was found to have severe right heart strain on point-of-care ultrasound (POCUS), suggesting a massive pulmonary embolism. Rapid bedside diagnosis using ultrasound expedited bedside cannulation and initiation of ECMO as a bridge to surgical thrombectomy, and ultimately the patient survived with full neurologic function. With its ready availability and increasing acceptance by consultants, POCUS should be incorporated into cardiac arrest algorithms as the standard of care to rule in thrombotic and obstructive causes of cardiac arrest.

Addressing the rising trend of high-risk pulmonary embolism mortality: Clinical and research priorities

BACKGROUND

Deaths from high-risk pulmonary embolism (PE) appear to have increased in the US over the last decade. Modifiable risks contributing to this worrisome trend present opportunities for physicians, researchers, and healthcare policymakers to improve care.

METHODS

We sought to contextualize contemporary, high-risk PE epidemiology and examine clinical trials, quality improvement opportunities, and healthcare policy initiatives directed at reducing mortality.

RESULTS

We observed significant and modifiable excess mortality due to high-risk PE. We identified several opportunities to improve care including: (1) rapid translation of forthcoming data on reperfusion strategies into clinical practice; (2) improved risk stratification tools; (3) quality improvement initiatives to address presumptive anticoagulation practice gaps; and (3) adoption of health policy initiatives to establish pulmonary embolism response teams and address the social determinants of health.

CONCLUSION

Addressing knowledge and practice gaps in intermediate and high-risk PE management must be prioritized and informed by forthcoming high-quality data. Implementation efforts are needed to improve acute PE management and resolve treatment disparities.

There is no such thing as a validated prediction model

BACKGROUND

Clinical prediction models should be validated before implementation in clinical practice. But is favorable performance at internal validation or one external validation sufficient to claim that a prediction model works well in the intended clinical context?

MAIN BODY

We argue to the contrary because (1) patient populations vary, (2) measurement procedures vary, and (3) populations and measurements change over time. Hence, we have to expect heterogeneity in model performance between locations and settings, and across time. It follows that prediction models are never truly validated. This does not imply that validation is not important. Rather, the current focus on developing new models should shift to a focus on more extensive, well-conducted, and well-reported validation studies of promising models.

CONCLUSION

Principled validation strategies are needed to understand and quantify heterogeneity, monitor performance over time, and update prediction models when appropriate. Such strategies will help to ensure that prediction models stay up-to-date and safe to support clinical decision-making.

Role of echocardiography in acute pulmonary embolism

Although pulmonary embolism (PE)-related mortality rate has decreased because of prompt diagnosis and effective therapy use, acute PE remains a potentially lethal disease. Due to its increasing prevalence, clinicians should pay attention to diagnosing and managing patients with acute PE. Echocardiography is the most commonly used method for diagnosing and managing acute PE; it also provides clues about hemodynamic instability in an emergency situation. It has been validated in the early risk stratification and impacts management strategies for treating acute PE. In hemodynamically unstable patients with acute PE, echocardiographic detection of right ventricular dysfunction is an indication for administering thrombolytics. In this review article, we discuss the role of echocardiography in the diagnosis and management of patients with acute PE.

Diagnostic Accuracy of Multiple D-Dimer Cutoff Thresholds and Other Clinically Applicable Biomarkers for the Detection and Radiographic Evaluation of Pulmonary Embolism

Background: Diagnostic work-up of pulmonary embolism (PE) remains a challenge. Methods: We retrospectively studied all patients referred for computed tomography pulmonary angiography (CTPA) with suspicion of PE during a 12-month period (2018). The diagnostic accuracy of different D-dimer (Dd) cutoff thresholds for ruling out PE was evaluated. Furthermore, the association of Dd and red cell distribution width (RDW) with embolus location, CTPA findings, and patient outcome was recorded. Results: One thousand seventeen (n = 1017) patients were finally analyzed (mean age: 64.6 years (SD = 11.8), males: 549 (54%)). PE incidence was 18.7%. Central and bilateral embolism was present in 44.7% and 59.5%, respectively. Sensitivity and specificity for conventional and age-adjusted Dd cutoff was 98.2%, 7.9%, and 98.2%, 13.1%, respectively. A cutoff threshold (2.1 mg/L) with the best (64.4%) specificity was identified based on Receiver Operating Characteristics analysis. Moreover, a novel proposed Dd cutoff (0.74 mg/L) emerged with increased specificity (20.5%) and equal sensitivity (97%) compared to 0.5 mg/L, characterized by concurrent reduction (17.2%) in the number of performed CTPAs. Consolidation/atelectasis and unilateral pleural effusion were significantly associated with PE (p < 0.05, respectively). Patients with consolidation/atelectasis or intrapulmonary nodule(s)/mass on CTPA exhibited significantly greater median Dd values compared to patients without the aforementioned findings (2.34, (IQR 1.29−4.22) vs. 1.59, (IQR 0.81−2.96), and 2.39, (IQR 1.45−4.45) vs. 1.66, (IQR 0.84−3.12), p < 0.001, respectively). RDW was significantly greater in patients who died during hospitalization (p = 0.012). Conclusions: Age-adjusted Dd increased diagnostic accuracy of Dd testing without significantly decreasing the need for imaging. The proposed Dd value (0.74 mg/L) showed promise towards reducing considerably the need of CTPA. Multiple radiographic findings have been associated with increased Dd values in our study.

Correlation and integration of circulating miRNA and peripheral whole blood gene expression profiles in patients with venous thromboembolism

The main aim of this work was to evaluate differential expression and biological functions of circulating miRNA and whole peripheral blood (PB) genes in patients affected by venous thromboembolism (VTE) and in healthy subjects. Circulating miRNA sequences and PB expression profiles were obtained from GEO datasets. Ten miRNAs with the most significant differential expression rate (dif-miRNA) were subjected to miRbase to confirm their identity. Dif-miRNA targets were predicted by TargetScan and aligned with differentially expressed genes to obtain overlapping co-genes. Biological functions of co-genes were analyzed by Gene Ontology and KEGG analysis. Interaction network of dif-miRNAs, co-genes, and their downstream pathways were studied by analyzing protein-protein interaction (PPI) clusters (STRING) and determining the crucial hubs (Cytoscape).MiR-522-3p and miR-134 dif-miRNAs are involved in protein translation and apoptosis by regulating their respective co-genes in PB. Co-genes are present in nucleolus and extracellular exosomes and are involved in oxidative phosphorylation and ribosome/poly(A)-RNA organization. The predicted PPI network covered 107 clustered genes and 220 marginal joints, where ten hub genes participating in PPIs were found. All these hub genes were down-regulated in VTE patients. Our study identifies new miRNAs as potential biological markers and therapeutic targets for VTE.

Risk scoring models fail to predict pulmonary embolism in trauma patients

BACKGROUND

We aimed to identify risk factors and risk scoring models to help identify post-traumatic pulmonary embolisms (PE).

METHODS

We performed a retrospective review (2014-2019) of all adult trauma patients admitted to our Level I trauma center that received a CT pulmonary angiogram (CTPA) for a suspected PE. A systematic literature search found eleven risk scoring models, all of which were applied to these patients. Scores of patients with and without PE were compared.

RESULTS

Of the 235 trauma patients that received CTPA, 31 (13%) showed a PE. No risk scoring model had both a sensitivity and specificity above 90%. The Wells Score had the highest area under the curve (0.65). After logistic regression, no risk scoring model variables were independently associated with PE.

CONCLUSIONS

In trauma patients with clinically suspected PE, clinical variables and current risk scoring models do not adequately differentiate patients with and without PE.

Pulmonary Embolism: A Practical Guide for the Busy Clinician

Acute pulmonary embolism (PE) is the third most common acute cardiovascular condition, and its prevalence increases over time. D-dimer has a very high negative predictive value, and if normal levels of D-dimer are detected, the diagnosis of PE is very unlikely. The final diagnosis should be confirmed by computed tomographic scan. However, echocardiography is the most available, bedside, low-cost, diagnostic procedure for patients with PE. Risk stratification is of utmost importance and is mainly based on hemodynamic status of the patient. Patients with PE and hemodynamic stability require further risk assessment, based on clinical symptoms, imaging, and circulating biomarkers.

The Use of Antithrombotics in Critical Illness

Hypercoagulable tendencies may develop in critically ill dogs and to a less known extent, cats. Although the use of antithrombotics is well-established in critically ill people, the indications and approach are far less well-known in dogs and cats. The goal of this article was to review the relevant CURATIVE guidelines, as well as other sources, and to provide recommendations for critically ill patients with directions for future investigation.

Provider Perspectives on the Use of Evidence-based Risk Stratification Tools in the Evaluation of Pulmonary Embolism: A Qualitative Study

OBJECTIVES

Providers often pursue imaging in patients at low risk of pulmonary embolism (PE), resulting in imaging yields <10% and false-positive imaging rates of 10% to 25%. Attempts to curb overtesting have had only modest success and no interventions have used implementation science frameworks. The objective of this study was to identify barriers and facilitators to the adoption of evidence-based diagnostic testing for PE.

METHODS

We conducted semistructured interviews with a purposeful sample of providers. An interview guide was developed using the implementation science frameworks, consolidated framework for implementation research, and theoretical domains framework. Interviews were recorded, transcribed, and analyzed in an iterative process. Emergent themes were identified, discussed, and organized.

RESULTS

We interviewed 23 providers from four hospital systems, and participants were diverse with regard to years in practice and practice setting. Barriers were predominately at the provider level and included lack of knowledge of the tools, particularly misunderstanding of the validated scoring systems in Wells, as well as risk avoidance and need for certainty. Barriers to prior implementation strategies included the perception of a clinical decision support (CDS) tool for PE as adding steps with little value; most participants reported that they overrode CDS interventions because they had already made the decision. All providers identified institution-level strategies as facilitators to use, including endorsed guidelines, audit feedback with peer comparison about imaging yield, and peer pressure.

CONCLUSIONS

This exploration of the use of risk stratification tools in the evaluation of PE found that barriers to use primarily exist at the provider level, whereas facilitators to the use of these tools are largely perceived at the level of the institution. Future efforts to promote the evidence-based diagnosis of PE should be informed by these determinants.

High-Risk Chief Complaints I: Chest Pain-The Big Three (an Update)

Nontraumatic chest pain is a frequent concern of emergency department patients, with causes that range from benign to immediately life threatening. Identifying those patients who require immediate/urgent intervention remains challenging and is a high-risk area for emergency medicine physicians where incorrect or delayed diagnosis may lead to significant morbidity and mortality. This article focuses on the 3 most prevalent diagnoses associated with adverse outcomes in patients presenting with nontraumatic chest pain, acute coronary syndrome, thoracic aortic dissection, and pulmonary embolism. Important aspects of clinical evaluation, diagnostic testing, treatment, and disposition and other less common causes of lethal chest pain are also discussed.

Over-Testing for Suspected Pulmonary Embolism in American Emergency Departments: The Continuing Epidemic

BACKGROUND

No recent data have investigated rates of diagnostic testing for pulmonary embolism (PE) in US emergency departments (EDs), and no data have examined computed tomographic pulmonary angiography (CTPA) rates in subgroups at high risk for adverse imaging outcomes, including young women and children. We hypothesized that over-testing for PE remains a problem.

METHODS AND RESULTS

We used electronic health record and billing data for 16 EDs in Indiana and 11 hospitals in the Dallas-Fort Worth area from 2016 to 2019 to locate ED patients who had any of the following: D-dimer, CTPA, scintillation ventilation perfusion lung scanning or formal pulmonary angiography. The primary outcomes were ED encounter volume-adjusted CTPA rate, PE yield rate with subgroup reporting for children (<18 years) and women under 45 years. We also examined the most frequent diagnoses. From a total visit volume of 1 828 010 patient encounters, 97 125 (5.3% of the total volume) had a diagnostic test for PE, including 25 870 patients who had CTPA order without D-dimer (59% of all tests for PE). The yield rate for PE from CTPA scans was 1.3% (1.1%-1.5%) in Indiana and 4.8% (4.2%-5.1%) in Dallas-Fort Worth (pooled rate 3.1%). Linear regression showed that increased D-dimer ordering correlated with increased PE yield rate (Pearson's R²=0.43; P<0.001). From the pooled sample, 59% of CTPAs done were in women, with 21% of all CTPAs performed on women under 45 years of age, and 1.4% (1.3%-1.5%) on children. The most frequent diagnoses were symptom-based descriptions of chest pain (34%) and shortness of breath (6.5%) and the condition-based diagnosis of pneumonia (4.1%).

CONCLUSIONS

Over-testing for PE in American EDs remains a major public health problem. Centers with higher D-dimer ordering had higher yield of PE on CTPA. These data suggest the potential for implementation of D-dimer based protocols to reduce low-yield CTPA ordering.

Evaluation of Cancer Patients With Suspected Pulmonary Embolism: Performance of the American College of Physicians Guideline

BACKGROUND

Accurate risk stratification of pulmonary embolism (PE) can reduce unnecessary imaging. We investigated the extent to which the American College of Physicians (ACP) guideline for evaluation of patients with suspected PE could be applied to cancer patients in the emergency department of a comprehensive cancer center.

MATERIALS AND METHODS

Data from cancer patients who underwent CT pulmonary angiography (CTPA) between August 1, 2015, and October 31, 2015, were collected. We assessed each patient's diagnostic workup for its adherence to the ACP guideline in terms of clinical risk stratification and age-adjusted d-dimer level and the degree to which these factors were associated with PE.

RESULTS

Of the 380 patients identified, 213 (56%) underwent CTPA indicated per the ACP guideline, and 78 (21%) underwent CTPA not indicated per the guideline. Only one of the patients who underwent nonindicated CTPA had a PE. Fifty-seven patients underwent unnecessary d-dimer evaluation, and 71 patients with negative d-dimer test results underwent nonindicated CTPA. PEs were found in 6 of 108 (6%) low-risk patients, 22 of 219 (10%) intermediate-risk patients, and 13 of 53 (25%) high-risk patients. The ACP guideline had negative predictive value of 99% (95% confidence interval: 93%-100%) and sensitivity of 97% (95% confidence interval: 86%-100%) in predicting PE.

CONCLUSION

The ACP guideline has good sensitivity for detecting PE in cancer patients and thus can be applied in this population. Compliance with the ACP guideline when evaluating cancer patients with suspected PE could reduce the use of unnecessary imaging and laboratory studies.

Clinical Probability Tools for Deep Venous Thrombosis, Pulmonary Embolism, and Bleeding

Overdiagnosis of venous thromboembolism is associated with increasing numbers of patient complications and health care burden. Multiple clinical tools exist to estimate the probability of pulmonary embolism and deep venous thrombosis. When used with d-dimer testing, these can further stratify venous thromboembolism risk to help inform the use of additional diagnostic testing. Although there are similar tools to estimate bleeding risk, these are not as well-validated and lack reliability.

An Evaluation of Guideline-Discordant Ordering Behavior for CT Pulmonary Angiography in the Emergency Department

PURPOSE

The aim of this study was to determine rates of and possible reasons for guideline-discordant ordering of CT pulmonary angiography for the evaluation of suspected pulmonary embolism (PE) in the emergency department.

METHODS

A retrospective review was performed of 212 consecutive encounters (January 6, 2016, to February 25, 2016) with 208 unique patients in the emergency department that resulted in CT pulmonary angiography orders. For each encounter, the revised Geneva score and two versions of the Wells criteria were calculated. Each encounter was then classified using a two-tiered risk stratification method (PE unlikely versus PE likely). Finally, the rate of and possible explanations for guideline-discordant ordering were assessed via in-depth chart review.

RESULTS

The frequency of guideline-discordant studies ranged from 53 (25%) to 79 (37%), depending on the scoring system used; 46 (22%) of which were guideline discordant under all three scoring systems. Of these, 18 (39%) had at least one patient-specific factor associated with increased risk for PE but not included in the risk stratification scores (eg, travel, thrombophilia).

CONCLUSIONS

Many of the guideline-discordant orders were placed for patients who presented with evidence-based risk factors for PE that are not included in the risk stratification scores. Therefore, guideline-discordant ordering may indicate that in the presence of these factors, the assessment of risk made by current scoring systems may not align with clinical suspicion.

Diagnosis of pulmonary embolism: Following the evidence from suspicion to certainty

Accurate, timely and cost-effective identification of pulmonary embolism remains a diagnostic challenge. This article reviews the pulmonary embolism diagnostic process with a focus on the best practice advice from the American College of Physicians. Benefits and risks of each diagnostic step are discussed. Emerging diagnostic tools, not included in the algorithm, are briefly reviewed.

Retrospective validation of the pulmonary embolism rule-out criteria rule in 'PE unlikely' patients with suspected pulmonary embolism

INTRODUCTION

Patients presenting to emergency departments (EDs) with suspected pulmonary embolism (PE) can be risk stratified and those who are deemed to be at low risk for PE usually undergo D-dimer testing. A negative D-dimer in this low-risk group rules out PE with a high degree of certainty because of its high sensitivity. The D-dimer is, however, a poorly specific test and positive results often lead to unnecessary radiological imaging (notably computed tomography pulmonary angiography). The Pulmonary Embolism Rule-Out Criteria (PERC) rule has been suggested as an alternative to D-dimer testing in these patients. This study looked at whether the PERC rule could safely replace the use of D-dimer in patients suspected of PE, but deemed 'PE unlikely' by the dichotomized Wells score in a UK ED setting.

PATIENTS AND METHODS

This was a retrospective review of 986 patients with suspected PE who had a blood sample for D-dimer level taken. In patients deemed 'PE unlikely' (using the dichotomized Wells score), the diagnostic performance of the PERC rule was compared with a standard D-dimer level in the detection of PE at index presentation and up to 3 months afterwards.

RESULTS

Of the 986 patients, 940 patients were deemed 'PE unlikely' using the dichotomized Wells score. Three patients with confirmed PE would have been missed by the PERC rule compared with only one missed by the D-dimer test. In these patients, the sensitivity of the PERC rule for detecting PE was 91.4% [95% confidence interval (CI): 76.9-98.2%], with a negative likelihood ratio of 0.25 (95% CI: 0.08-0.73). However, the negative predictive value of the PERC rule was 99.1% (95% CI: 97.3-99.8%). In comparison, the sensitivity for the standard D-dimer test was 97.1% (95% CI: 85.1-99.9%), with a negative likelihood ratio of 0.04 (95% CI: 0.01-0.27). The negative predictive value for the standard D-dimer test was 99.8% (95% CI: 99.2-100%).

CONCLUSION

The PERC rule has a high negative predictive value for excluding PE in patients presenting with suspected PE to the ED. However, the PERC rule may still miss around 8% of confirmed PE in patients who are deemed 'PE unlikely' by a dichotomized Wells score. Caution is advised in using the PERC rule as a substitute for the standard D-dimer test in all these patients.

Investigation of age-adjusted D-dimer using an uncommon assay

BACKGROUND

Use of an age-adjusted D-dimer for the evaluation of acute pulmonary embolus (PE) has been prospectively validated in the literature and has become a practice recommendation from major medical societies. Most research on this subject involves the most common D-dimer assays reporting in Fibrinogen Equivalent Units (FEU) with a non-age-adjusted manufacturer-recommended cutoff of 500 ng/ml FEU. Limited research to date has evaluated age-adjustment in assays that report in D-Dimer Units (D-DU), which use a manufacturer-recommended cutoff of 230 ng/ml D-DU. Despite scant evidence, an age-adjusted formula using D-DU has been recently endorsed by the American College of Emergency Physicians (ACEP). This formula seems arbitrary in its derivation and unnecessarily deviates from existing thresholds, thus prompting the creation of our novel-age adjustment formula. The goal of this study was to retrospectively evaluate the test characteristics of our novel age-adjusted D-dimer formula using the D-DU assay in comparison to existing traditional and age-adjusted D-dimer thresholds for the evaluation of acute PE in the ED.

METHODS

This was a retrospective chart review at an academic quaternary health system with three EDs and 195,000 combined annual ED visits. Only patients with D-dimer testing and CT PE protocol (CTPE) imaging were included. Admission and discharge diagnosis codes were used to identify acute PE. Outcome measures were sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of an unadjusted traditional threshold (230) compared with both novel and ACEP-endorsed age adjusted thresholds, (Age × 5) - 20 and Age × 5 if >50, respectively. Estimates with their exact 95% threshold were performed.

RESULTS

4846 adult patients were evaluated from January 2012 to July 2017. Group characteristics include a mean age of 52 and a frequency of acute PE diagnosis by CTPE of 8.25%. Traditional D-dimer cutoff demonstrated a sensitivity of 99.8% (95% CI 98.6-100), specificity of 16.7% (95% CI 15.6-17.8) and NPV of 99.9% (95% CI 99.3-100). Our novel age-adjusted D-dimer thresholds had a sensitivity of 97.0% (95% CI 94.8-98.4), specificity of 27.9% (95% CI 26.6-29.2) and NPV of 99.0% (95% CI 98.3-99.5) with the ACEP-endorsed formula demonstrating similar test characteristics.

CONCLUSION

Use of an age-adjusted D-dimer on appropriately selected patients being evaluated for acute PE in the ED with a D-DU assay increases specificity while maintaining a high sensitivity and NPV. Both our novel formula and the ACEP-endorsed age-adjusted formula performed well, with our novel formula showing a trend towards improved testing characteristics.

Reliability of the CARE rule and the HEART score to rule out an acute coronary syndrome in non-traumatic chest pain patients

In patients consulting in the Emergency Department for chest pain, a HEART score ≤ 3 has been shown to rule out an acute coronary syndrome (ACS) with a low risk of major adverse cardiac event (MACE) occurrence. A negative CARE rule (≤ 1) that stands for the first four elements of the HEART score may have similar rule-out reliability without troponin assay requirement. We aim to prospectively assess the performance of the CARE rule and of the HEART score to predict MACE in a chest pain population. Prospective two-center non-interventional study. Patients admitted to the ED for non-traumatic chest pain were included, and followed-up at 6 weeks. The main study endpoint was the 6-week rate of MACE (myocardial infarction, coronary angioplasty, coronary bypass, and sudden unexplained death). 641 patients were included, of whom 9.5% presented a MACE at 6 weeks. The CARE rule was negative for 31.2% of patients, and none presented a MACE during follow-up [0, 95% confidence interval: (0.0-1.9)]. The HEART score was ≤ 3 for 63.0% of patients, and none presented a MACE during follow-up [0% (0.0-0.9)]. With an incidence below 2% in the negative group, the CARE rule seemed able to safely rule out a MACE without any biological test for one-third of patients with chest pain and the HEART score for another third with a single troponin assay.

The DAGMAR Score: D-dimer assay-guided moderation of adjusted risk. Improving specificity of the D-dimer for pulmonary embolism

We generated a novel scoring system to improve the test characteristics of D-dimer in patients with suspected PE (pulmonary emboli). Electronic Medical Record data were retrospectively reviewed on Emergency Department (ED) patients 18 years or older for whom a D-dimer and imaging were ordered between June 4, 2012 and March 30, 2016. Symptoms (dyspnea, unilateral leg swelling, hemoptysis), age, vital signs, medical history (cancer, recent surgery, medications, history of deep vein thrombosis or PE, COPD, smoking), laboratory values (quantitative D-dimer, platelets, and mean platelet volume (MPV)), and imaging results (CT, VQ) were collected. Points were designated to factors that were significant in two multiple regression analyses, for PE or positive D-dimer. Points predictive of PE were designated positive values and points predictive of positive D-dimer, irrespective of presence of PE, were designated negative values. The DAGMAR (D-dimer Assay-Guided Moderation of Adjusted Risk) score was developed using age and platelet adjustment and points for factors associated with PE and elevated D-dimer. Of 8486 visits reviewed, 3523 were unique visits with imaging, yielding 2253 (26.5%) positive D-dimers. 3501 CT scans and 156 VQ scans were completed, detecting 198 PE. In our cohort, a DAGMAR Score < 2 equated to overall PE risk < 1.2%. Specificity improved (38% to 59%) without compromising sensitivity (94% to 96%). Use of the DAGMAR Score would have reduced CT scans from 2253 to 1556 and lead to fewer false negative results. By considering factors that affect D-dimer and also PE, we improved specificity without compromising sensitivity.

Isolated proximal greater saphenous vein thrombosis and the risk of propagation to deep vein thrombosis and pulmonary embolism

Objectives

Greater saphenous vein (GSV) thrombosis is concerning due to its close proximity to the deep femoral vein. This study sought to identify the risk of propagation to deep vein thrombosis (DVT) or pulmonary embolism (PE) among patients with isolated proximal GSV superficial thrombosis and describe provider practice patterns related to treatment.

Materials and methods

This is an Institutional Review Board-approved retrospective multi-center study. Patients presented to one of three possible emergency departments in a large health system. About 21,716 patients were queried through the electronic medical record. Ninety-five patients or 0.4% of study subjects met inclusion criteria of isolated proximal GSV thrombosis. Forty-five patients were excluded, leaving a final data set of 40 patients. Investigators recorded radiology impressions, patient demographics, past medical history, DVT/PE risk factors, and treatment plans. Propagation of GSV thrombosis to DVT/PE was also noted. Follow-up methods included chart review, primary care physician follow-up, and direct, scripted patient follow-up phone calls. Descriptive statistics were applied to study subjects using SAS for Windows, version 9.3.

Results

Three patients (7.5%) had progression of GSV thrombosis to DVT/PE. Twenty percent of patients without malignancy were treated with anticoagulation compared to 14% of those with preexisting malignancy upon initial diagnosis of isolated GSV thrombosis. Forty-five percent of patients were prescribed some type of supportive therapy to aid in the treatment of GSV thrombosis.

Conclusion

Isolated proximal GSV thrombosis, while uncommon, may frequently progress to DVT or PE. Our work suggests clinicians should consider anticoagulation for isolated GSV thrombosis.

Long-Term Experience With a Mandatory Clinical Decision Rule and Mandatory d-Dimer in the Evaluation of Suspected Pulmonary Embolism

PURPOSE

This study evaluated the long-term effectiveness of mandatory assignment of both a clinical decision rule (CDR) and highly sensitive d-dimer in the evaluation of patients with suspected pulmonary embolism (PE).

MATERIALS AND METHODS

Institutional guidelines with a CDR and highly sensitive d-dimer were embedded in an order entry menu with mandatory assignment of key components before ordering a CT pulmonary angiogram (CTPA). Data were retrospectively extracted from the electronic health record.

RESULTS

This was a retrospective review of 1,003 CTPA studies (905 patients, 845 male and 60 female patients, age 63.7 ± 13.5 years). CTPAs were positive for PE in 170 studies (17%), representing an average yield of 15% (year [average]; 2007 [15%], 2008 [18%], 2009 [15%], 2010 [15%], 2011 [17%], 2012 [15%], 2013 [23%]). The increased yield represented efforts of mandatory order entry assignments, educational sessions, and clinical champions. Different d-dimer thresholds with or without age adjustments in combination with the CDR identified about 10% of patients who may have been managed without CTPA.

CONCLUSION

Mandatory assignment of a CDR and highly sensitive d-dimer clinical decision pathway can be successfully incorporated into an order entry menu and produce a sustained increase in CTPA yield of patients with suspected PE.

Central Venous Catheter-directed Tissue Plasminogen Activator in Massive Pulmonary Embolism

We present the case of an 88-year-old female who presented to the emergency department (ED) with suspected massive pulmonary embolism (PE) causing respiratory failure, right heart strain, and shock, who despite early and aggressive resuscitation with vasopressors and continuous peripheral infusion of tissue plasminogen activator (tPA), suffered a cardiac arrest in the ED. We describe the approach of a tPA bolus directed through a central venous catheter, resulting in return of spontaneous circulation and immediate improvement in physiologic parameters prior to confirmation of PE with computed tomography angiogram. We further hypothesize that in patients deemed too unstable to be transferred for embolectomy or catheter-directed thrombolysis, central venous catheter-directed bolus tPA may be more effective than peripheral infusion alone.

CT Pulmonary Angiography in Young Women

The purpose was to determine whether young women in the emergency department who received computed tomographic (CT) pulmonary angiograms were evaluated to receive lower dose imaging or no imaging, recognizing that the risks of radiation are particularly high in young women. This was a retrospective cohort investigation of women aged 18 to 29 years seen for suspected acute pulmonary embolism in emergency departments of 5 regional hospitals from May 1, 2015 to April 30, 2016. Computed tomographic (CT) pulmonary angiograms were obtained in 379 young women. Pulmonary embolism was diagnosed by CT angiography in 2.1%. A Wells probability score could be calculated in 11.9%. D-dimer was obtained in 46.2% and a chest radiograph was obtained in 41.7%. Among patients with a normal chest radiograph, 3.9% had a lung scan. Venous ultrasound of the lower extremities was obtained in 1.8%. Each had an elevated D-dimer. Among the young women who received CT angiograms, 53 were pregnant. In 17.0% of pregnant women, a Wells clinical probability score could be calculated from the medical record. D-dimer in pregnant women was obtained in 30.2%, chest radiograph in 22.6%, lung scan in 11.3%, and venous ultrasound of the lower extremities in none. In conclusion, young women and pregnant women often received CT pulmonary angiograms for suspected acute pulmonary embolism without an objective clinical assessment, measurement of D-dimer, lung scintiscan, or venous ultrasound, which may have eliminated the need for CT pulmonary angiography in many instances.

Ruling out Pulmonary Embolism in Patients with High Pretest Probability

Introduction

The American College of Emergency Physicians guidelines recommend more aggressive workup beyond imaging alone in patients with a high pretest probability (PTP) of pulmonary embolism (PE). However, the ability of multiple tests to safely rule out PE in high PTP patients is not known. We sought to measure the ability of negative computed tomography pulmonary angiography (CTPA) along with negative D-dimer to rule out PE in these high-risk patients.

Methods

We analyzed data from a previous prospective observational study conducted in 12 emergency departments (ED). Wells score criteria were entered by providers before final PE testing. PE was diagnosed by imaging on the index ED visit, or within 45 days, demonstrating either PE or deep vein thrombosis (DVT), or if the patient died of PE during the 45-day, follow-up period. Testing threshold was set at 1.8%.

Results

A total of 7,940 patients were enrolled and tested for PE, and 257 had high PTP (Wells >6). Sixteen of these high-risk patients had negative CTPA and negative D-dimer, of whom two were positive for PE (12.5% [95% confidence interval {2.2%–40.0%}]). One of these patients had a DVT on CT venogram and the other was diagnosed at follow-up.

Conclusion

Our analysis suggests that in patients with high PTP of PE, neither negative CTPA by itself nor a negative CTPA plus a negative D-dimer are sufficient to rule out PE. More aggressive workup strategies may be required for these patients.

Use of the d-dimer for Detecting Pulmonary Embolism in the Emergency Department

BACKGROUND

Assessment for pulmonary embolism (PE) in the emergency department (ED) remains complex, involving clinical decision tools, blood tests, and imaging.

OBJECTIVE

Our objective was to examine the test characteristics of the high-sensitivity d-dimer for the diagnosis of PE at our institution and evaluate use of the d-dimer and factors associated with a falsely elevated d-dimer.

METHODS

We retrospectively collected data on adult patients evaluated with a d-dimer and computed tomography (CT) pulmonary angiogram or ventilation perfusion scan at two EDs between June 4, 2012 and March 30, 2016. We collected symptoms (dyspnea, unilateral leg swelling, hemoptysis), vital signs, and medical and social history (cancer, recent surgery, medications, history of deep vein thrombosis or PE, chronic obstructive pulmonary disease, smoking). We calculated test characteristics, including sensitivity, specificity, and likelihood ratios for the assay using conventional threshold and with age adjustment, and performed a univariate analysis.

RESULTS

We found 3523 unique visits with d-dimer and imaging, detecting 198 PE. Imaging was pursued on 1270 patients with negative d-dimers, revealing 9 false negatives, and d-dimer was sent on 596 patients for whom negative Pulmonary Embolism Rule-Out Criteria (PERC) were documented with 2% subsequent radiographic detection of PE. The d-dimer showed a sensitivity of 95.7% (95% confidence interval [CI] 91-98%), specificity of 40.0% (95% CI 38-42%), negative likelihood ratio of 0.11 (95% CI 0.06-0.21), and positive likelihood ratio of 1.59 (95% CI 1.53-1.66) for the radiographic detection of PE. With age adjustment, 347 of the 2253 CT scans that were pursued in patients older than 50 years with an elevated d-dimer could have been avoided without missing any additional PE. Many risk factors, such as age, history of PE, recent surgery, shortness of breath, tachycardia and hypoxia, elevated the d-dimer, regardless of the presence of PE.

CONCLUSIONS

Many patients with negative d-dimer and PERC still received imaging. Our data support the use of age adjustment, and perhaps adjustment for other factors seen in patients evaluated for PE.

Pulmonary Embolism Testing Among Emergency Department Patients Who Are Pulmonary Embolism Rule-out Criteria Negative

OBJECTIVE

Previous studies have demonstrated that rates of pulmonary embolism (PE) testing have increased without a concomitant decrease in PE-related mortality. The Pulmonary Embolism Rule-out Criteria (PERC) intend to reduce testing for PE in the emergency department (ED) by identifying low-risk patients ("PERC-negative") who do not require D-dimer, computed tomography pulmonary angiogram (CTPA), or ventilation/perfusion (VQ) scan for PE. This study assesses PE testing rates among PERC-negative patients presenting to an urban academic ED.

METHODS

We prospectively enrolled a convenience sample of ED patients with chest pain and/or shortness of breath presenting between June 2010 and December 2015. We recorded baseline variables at the time of ED presentation, information on testing performed in the ED, and the diagnosis of acute PE during the ED visit. We classified patients as PERC-positive or PERC-negative utilizing baseline variables and clinical characteristics.

RESULTS

Of the 3,024 study patients, 54.8% (95% confidence interval = 53%-56.5%) were female and the mean age was 51.7 (51.1-52.3) years. A total of 17.5% (16.2%-18.9%) of study patients were PERC-negative and 33.7% (32%-35.4%) of all patients underwent testing for PE. A total of 25.5% (22%-29.4%) of PERC-negative patients had PE testing compared to 35.4% (33.6%-37.3%) of PERC-positive patients (p < 0.001). A total of 7.2% (5.3%-9.7%) of PERC-negative patients had advanced imaging without a D-dimer compared to 19.2% (17.8%-20.8%) of PERC-positive patients (p < 0.001). In multivariate analysis, factors associated with PE testing in PERC-negative patients included age, white non-Hispanic race/ethnicity, pleuritic chest pain, and a complaint of both chest pain and shortness of breath. Two PERC-negative patients (0.4%) were diagnosed with an acute PE in the ED compared to 2.2% of PERC-positive patients (p = 0.008). The overall testing yield for PE was 1.6% (0.4%-9.2%) among PERC-negative patients versus 6.3% (4.9%-8.1%) among PERC-positive patients (p = 0.017).

CONCLUSION

In an academic ED, a significant proportion of PERC-negative patients underwent testing for PE, including CT or VQ scan without D-dimer risk stratification. Future areas of research may include evaluating factors that lead clinicians to pursue PE testing in PERC-negative patients and implementing clinical pathways to minimize practice variability among these patients.

Knowledge Translation of the PERC Rule for Suspected Pulmonary Embolism: A Blueprint for Reducing the Number of CT Pulmonary Angiograms

Introduction

Computerized decision support decreases the number of computed tomography pulmonary angiograms (CTPA) for pulmonary embolism (PE) ordered in emergency departments, but it is not always well accepted by emergency physicians. We studied a department-endorsed, evidence-based clinical protocol that included the PE rule-out criteria (PERC) rule, multi-modal education using principles of knowledge translation (KT), and clinical decision support embedded in our order entry system, to decrease the number of unnecessary CTPA ordered.

Methods

We performed a historically controlled observational before-after study for one year pre- and post-implementation of a departmentally-endorsed protocol. We included patients > 18 in whom providers suspected PE and who did not have a contraindication to CTPA. Providers entered clinical information into a diagnostic pathway via computerized order entry. Prior to protocol implementation, we provided education to ordering providers. The primary outcome measure was the number of CTPA ordered per 1,000 visits one year before vs. after implementation.

Results

CTPA declined from 1,033 scans for 98,028 annual visits (10.53 per 1,000 patient visits (95% CI [9.9–11.2]) to 892 scans for 101,172 annual visits (8.81 per 1,000 patient visits (95% CI [8.3–9.4]) p<0.001. The absolute reduction in PACT ordered was 1.72 per 1,000 visits (a 16% reduction). Patient characteristics were similar for both periods.

Conclusion

Knowledge translation clinical decision support using the PERC rule significantly reduced the number of CTPA ordered.

Prevalence of Pulmonary Embolism in Patients Presenting to the Emergency Department for Syncope

The Research to Practice column is intended to improve the research critique skills of the advanced practice registered nurse and the emergency nurse (RN) and to assist with the translation of research into practice. For each column, a topic and a research study are selected. The research article is then reviewed and critiqued, and the findings are discussed in relation to a patient scenario. In this column, we examine the findings of P. from their article, titled "Prevalence of Pulmonary Embolism Among Patients Hospitalized for Syncope."

Never say never: Identification of acute pulmonary embolism on non-contrast computed tomography imaging

Acute undifferentiated illness remains a critical challenge for the emergency physician. The diagnostic evaluation and treatment decisions on such severely ill patients often needs to be made in an expedited fashion. Situations occur wherein the ideal or recommended workup is not always feasible due to time or patient specific factors. We present two cases of patients with undifferentiated acute illness who had undergone non-contrast CT (computed tomography) scanning and subsequently had central pulmonary embolism identified upon careful review of their CT studies.

Negative D-dimer testing excludes pulmonary embolism in non-high risk patients in the emergency department

PURPOSE

The purpose of this study was to assess the ability of d-dimer testing to obviate the need for cross-sectional imaging for patients at "non-high risk" for pulmonary embolism (PE).

METHODS

This is a retrospective study of emergency department patients at an academic medical center who underwent cross-sectional imaging (MRA or CTA) to evaluate for PE from 2008 to 2013. The primary outcome was the NPV of d-dimer testing when used in conjunction with clinical decision instruments (CDIs = Wells', Revised Geneva, and Simplified Revised Geneva Scores). The reference standard for PE status included image test results and a 6-month chart review follow-up for venous thromboembolism as a proxy for false negative imaging. Secondary analyses included ROC curves for each CDI and calculation of PE prevalence in each risk stratum.

RESULTS

Of 459 patients, 41 (8.9%) had PE. None of the 76 patients (16.6%) with negative d-dimer results had PE. Thus, d-dimer testing had 100% sensitivity and NPV, and there were no differences in CDI performance. Similarly, when evaluated independently of d-dimer results, no CDI outperformed the others (areas under the ROC curves ranged 0.53-0.55). There was a significantly higher PE prevalence in the high versus "non-high risk" groups when stratified by the Wells' Score (p = 0.03).

CONCLUSIONS

Negative d-dimer testing excluded PE in our retrospective cohort. Each CDI had similar NPVs, whether analyzed in conjunction with or independently of d-dimer results. Our results confirm that PE can be safely excluded in patients with "non-high risk" CDI scores and a negative d-dimer.

Clinical Mimics: An Emergency Medicine-Focused Review of Asthma Mimics

BACKGROUND

Asthma is a common diagnosis or preexisting condition, and many patients with acute asthma exacerbation may present to the emergency department with wheezing and respiratory distress. However, many conditions may mimic this presentation.

OBJECTIVES

This review provides an overview of common asthma mimics and an approach to evaluation and management.

DISCUSSION

Asthma is characterized by an obstructive pulmonary disease with recurrent exacerbations. The disease may present with a variety of symptoms, including wheezing, chest tightness, shortness of breath, and even respiratory failure. Mimics include anaphylaxis, angioedema, central airway obstruction, heart failure, allergic reaction, foreign body aspiration, pulmonary embolism, and vocal cord dysfunction. The approach to evaluation and management of these patients includes assessment for life-threatening conditions while treatment and resuscitation is underway. Providers should assess for red flags, including no history of asthma, lack of severe asthma, and no improvement with standard treatments. Focused assessment with history, physical examination, chest imaging, electrocardiogram, and laboratory studies may provide benefit. Through consideration of these mimics and treatment, providers can provide rapid management.

CONCLUSIONS

While asthma is a common disease, many asthma mimics exist. Through consideration of other diseases with wheezing and assessing for red flags, such as patients presenting without a history of asthma or patients with a history of only mild asthma presenting with severe symptoms, emergency providers may decrease the chance of early diagnostic closure and anchoring while improving the care of these patients.

D-Dimer Use and Pulmonary Embolism Diagnosis in Emergency Units: Why Is There Such a Difference in Pulmonary Embolism Prevalence between the United States of America and Countries Outside USA?

OBJECTIVE

Although diagnostic guidelines are similar, there is a huge difference in pulmonary embolism (PE) prevalence between the United States of America (US) and countries outside the USA (OUS) in the emergency care setting. In this study, we prospectively analyze patients' characteristics and differences in clinical care that may influence PE prevalence in different countries.

METHODS

An international multicenter prospective diagnostic study was conducted in a standard-of-care setting. Consecutive outpatients presenting to the emergency unit and suspected for PE were managed using the Wells score, STA-Liatest® D-Dimers and imaging.

RESULTS

The prevalence of PE in the study was 7.9% in low and moderate risk patients. Among the 1060 patients with low or moderate pre-test probability (PTP), PE prevalence was four times higher in OUS (10.7%) than in the US (2.5%) (P < 0.0001). The mean number of imaging procedures performed for one new PE diagnosis was 3.3 in OUS vs 17 in the US (P < 0.001). Stopping investigation in the case of negative D-dimers (DD combined) with low/moderate PTP was more frequent in OUS (92.7%) than in the US (75.7%) (P < 0.01). Moreover, the use of imaging was much higher in the US (44.4% vs 19.2% in OUS) in the case of moderate PTP combined with negative DD.

CONCLUSION

Differences between US and OUS PE prevalence in emergency setting might be explained by differences in patients' characteristics and mostly in care patterns. US physicians performed computed tomographic pulmonary angiography more often than in Europe in cases of low/moderate PTP combined with negative DD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01221805.

Anemia is not a risk factor for developing pulmonary embolism

OBJECTIVE

Our aim was to validate the previously published claim of a positive relationship between low blood hemoglobin level (anemia) and pulmonary embolism (PE).

METHODS

This was a retrospective study of patients undergoing cross-sectional imaging to evaluate for PE at an academic medical center. Patients were identified using billing records for charges attributed to either magnetic resonance angiography or computed tomography angiography of the chest from 2008 to 2013. The main outcome measure was mean hemoglobin levels among those with and without PE. Our reference standard for PE status included index imaging results and a 6-month clinical follow-up for the presence of interval venous thromboembolism, conducted via review of the electronic medical record. Secondarily, we performed a subgroup analysis of only those patients who were seen in the emergency department. Finally, we again compared mean hemoglobin levels when limiting our control population to an age- and sex-matched cohort of the included cases.

RESULTS

There were 1294 potentially eligible patients identified, of whom 121 were excluded. Of the remaining 1173 patients, 921 had hemoglobin levels analyzed within 24 hours of their index scan and thus were included in the main analysis. Of those 921 patients, 107 (11.6%; 107/921) were positive for PE. We found no significant difference in mean hemoglobin level between those with and without PE regardless of the control group used (12.4 ± 2.1 g/dL and 12.3 ± 2.0 g/dL [P = .85], respectively).

CONCLUSIONS

Our data demonstrated no relationship between anemia and PE.

Detection of Pulmonary Embolism in High-Risk Children

OBJECTIVE

To evaluate 2 commonly used adult-based pulmonary embolism (PE) algorithms in pediatric patients and to derive a pediatric-specific clinical decision rule to evaluate children at risk for PE, given the paucity of data to guide diagnostic imaging in children for whom PE is suspected.

STUDY DESIGN

We performed a single-center retrospective study among 561 children <22 years of age undergoing either D-dimer testing or radiologic evaluation (computed tomography or ventilation-perfusion scan) in the emergency department setting for concern of PE. A diagnosis of PE required radiologic confirmation and anticoagulant treatment. We evaluated the test characteristics of the Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC) low-risk rule and used recursive partition analysis to derive a clinical decision rule.

RESULTS

Among the 561 patients included in the study, 36 (6.4%) were diagnosed with PE. The Wells criteria demonstrated a sensitivity and specificity of 86% and 60%, respectively. The sensitivity and specificity of the PERC were 100% and 24%, respectively. A clinical decision rule including the presence of oral contraceptive use, tachycardia, and oxygen saturation <95% demonstrated a sensitivity and specificity of 90% and 56%, respectively, a positive and negative likelihood ratio of 2.0 and 0.2, and a positive and negative predictive value of 0.12 and 0.99, respectively.

CONCLUSIONS

The risk of PE is low among children not receiving estrogen therapy and without tachycardia and hypoxia in those with an initial suspicion of PE. Application of the PERC rule and Wells criteria should be used cautiously in the pediatric population.

Optimizing CT Pulmonary Angiogram Utilization in a Community Emergency Department: A Pre- and Postintervention Study

PURPOSE

Optimizing the utilization of CT pulmonary angiogram (CTPA) for the diagnosis and workup of acute chest pain can provide an opportunity to reduce unnecessary radiation and health care system expense.

METHODS

An attempt to improve CTPA utilization began by measuring overall department and clinician-specific utilization. This was bolstered by retrospectively evaluating patient charts for pulmonary embolism scoring criteria and D-dimer utilization so as to better understand gaps in diagnostic workup. The department-wide and individualized metrics were then provided to each emergency department clinician and differences between the pre- and postintervention data were evaluated.

RESULTS

The percentage of positive CTPAs did not change significantly at 8.7% and 9.2% in the pre- and postintervention groups, respectively. Similarly, the workup of patients based on retrospective PERC and Wells-score criteria did not significantly improve after the intervention. However, the percentage of CTPAs ordered on low D-dimer patients did decrease significantly post-intervention. Further observational analysis uncovered marked variability in clinician ordering behavior and diagnostic rates.

CONCLUSIONS

Overall, such an intervention seems to have a limited, though not insignificant, impact on the workup of suspected pulmonary embolism. Calculating provider-specific utilization metrics allows both the radiologist and clinician to better understand opportunities to improve health care delivery.

Pulmonary embolism: the diagnosis, risk-stratification, treatment and disposition of emergency department patients

The diagnosis or exclusion of pulmonary embolism (PE) remains challenging for emergency physicians. Symptoms can be vague or non-existent, and the clinical presentation shares features with many other common diagnoses. Diagnostic testing is complicated, as biomarkers, like the D-dimer, are frequently false positive, and imaging, like computed tomography pulmonary angiography, carries risks of radiation and contrast dye exposure. It is therefore incumbent on emergency physicians to be both vigilant and thoughtful about this diagnosis. In recent years, several advances in treatment have also emerged. Novel, direct-acting oral anticoagulants make the outpatient treatment of low risk PE easier than before. However, the spectrum of PE severity varies widely, so emergency physicians must be able to risk-stratify patients to ensure the appropriate disposition. Finally, PE response teams have been developed to facilitate rapid access to advanced therapies (e.g., catheter directed thrombolysis) for patients with high-risk PE. This review will discuss the clinical challenges of PE diagnosis, risk stratification and treatment that emergency physicians face every day.