The Impact of Clinical Decision Rules on Computed Tomography Use and Yield for Pulmonary Embolism: A Systematic Review and Meta-analysis

Efficient management of pulmonary embolism diagnosis using a two-step interconnected machine learning model based on electronic health records data

Pulmonary Embolism (PE) is a life-threatening clinical disease with no specific clinical symptoms and Computed Tomography Angiography (CTA) is used for diagnosis. Clinical decision support scoring systems like Wells and rGeneva based on PE risk factors have been developed to estimate the pre-test probability but are underused, leading to continuous overuse of CTA imaging. This diagnostic study aimed to propose a novel approach for efficient management of PE diagnosis using a two-step interconnected machine learning framework directly by analyzing patients' Electronic Health Records data. First, we performed feature importance analysis according to the result of LightGBM superiority for PE prediction, then four state-of-the-art machine learning methods were applied for PE prediction based on the feature importance results, enabling swift and accurate pre-test diagnosis. Throughout the study patients' data from different departments were collected from Sina educational hospital, affiliated with the Tehran University of medical sciences in Iran. Generally, the Ridge classification method obtained the best performance with an F1 score of 0.96. Extensive experimental findings showed the effectiveness and simplicity of this diagnostic process of PE in comparison with the existing scoring systems. The main strength of this approach centered on PE disease management procedures, which would reduce avoidable invasive CTA imaging and be applied as a primary prognosis of PE, hence assisting the healthcare system, clinicians, and patients by reducing costs and promoting treatment quality and patient satisfaction.

Effect of a behavioral nudge on adoption of an electronic health record-agnostic pulmonary embolism risk prediction tool: a pilot cluster nonrandomized controlled trial

Objective

Our objective was to determine the feasibility and preliminary efficacy of a behavioral nudge on adoption of a clinical decision support (CDS) tool.

Materials and Methods

We conducted a pilot cluster nonrandomized controlled trial in 2 Emergency Departments (EDs) at a large academic healthcare system in the New York metropolitan area. We tested 2 versions of a CDS tool for pulmonary embolism (PE) risk assessment developed on a web-based electronic health record-agnostic platform. One version included behavioral nudges incorporated into the user interface.

Results

A total of 1527 patient encounters were included in the trial. The CDS tool adoption rate was 31.67%. Adoption was significantly higher for the tool that included behavioral nudges (39.11% vs 20.66%; P < .001).

Discussion

We demonstrated feasibility and preliminary efficacy of a PE risk prediction CDS tool developed using insights from behavioral science. The tool is well-positioned to be tested in a large randomized clinical trial.

Trial Registration

Clinicaltrials.gov (NCT05203185).

Risk factors for suspected pulmonary embolism in children: Complication of Mycoplasma pneumoniae pneumonia

PURPOSE

Pulmonary embolism (PE) is not a rare complication of Mycoplasma pneumoniae pneumonia (MPP) in children. We sought to determine the incidence of PE in children with MPP who underwent clinically indicated CT pulmonary angiography (CTPA) and to evaluate the risk factors for PE.

METHODS

All 106 children with MPP who were clinically suspected of having PE and who underwent CTPA were retrospectively enrolled from June 2018 to December 2021. The clinical features, laboratory data, and radiological parameters were recorded (e.g., lung consolidation involved and the Qanadli score). A Cox proportional hazards model and area under the receiver operating characteristic (ROC) curve were used to evaluate the risk factors and prognostic discriminatory capacity for PE.

RESULTS

PE was detected in 26 of 106 (24.5 %) children (mean age, 6.2 years ± 3.3 years; 53 boys). Sixteen of the 26 (61.5 %) children with PE were boys. The mean age of the children with PE was 8.1 ± 2.9 years, and the mean Qanadli score was 15.3 ± 10.2. Children with PE had higher D-dimer levels (9.3 ± 7.1 mg/Lvs. 3.6 ± 3.8 mg/L) and a greater frequency of lung lobe consolidation (25 (96.2 %) vs. 64 (80.0 %)) (all P < 0.05). For children with MPP, age (hazard ratio (HR) = 1.96 (95 % CI1.04, 3.71; P = 0.037), D-dimer level (HR = 1.52, 95 % CI: 1.03, 2.24; P = 0.029), and bilateral lung consolidation (HR = 2.41, 95 % CI: 1.03, 5.58; P = 0.043) were found to be independent predictors of PE.

CONCLUSION

Clinical and CT radiological predictors could be used to predict PE in children with MPP. The use of risk factor assessment as a tool has the potential to guide more appropriate use of CTPA in children.

Deployment of a human-centred clinical decision support system for pulmonary embolism: evaluation of impact on quality of diagnostic decisions

Pulmonary embolism (PE) is a serious condition that presents a diagnostic challenge for which diagnostic errors often happen. The literature suggests that a gap remains between PE diagnostic guidelines and adherence in healthcare practice. While system-level decision support tools exist, the clinical impact of a human-centred design (HCD) approach of PE diagnostic tool design is unknown.

DESIGN

Before-after (with a preintervention period as non-concurrent control) design study.

SETTING

Inpatient units at two tertiary care hospitals.

PARTICIPANTS

General internal medicine physicians and their patients who underwent PE workups.

INTERVENTION

After a 6-month preintervention period, a clinical decision support system (CDSS) for diagnosis of PE was deployed and evaluated over 6 months. A CDSS technical testing phase separated the two time periods.

MEASUREMENTS

PE workups were identified in both the preintervention and CDSS intervention phases, and data were collected from medical charts. Physician reviewers assessed workup summaries (blinded to the study period) to determine adherence to evidence-based recommendations. Adherence to recommendations was quantified with a score ranging from 0 to 1.0 (the primary study outcome). Diagnostic tests ordered for PE workups were the secondary outcomes of interest.

RESULTS

Overall adherence to diagnostic pathways was 0.63 in the CDSS intervention phase versus 0.60 in the preintervention phase (p=0.18), with fewer workups in the CDSS intervention phase having very low adherence scores. Further, adherence was significantly higher when PE workups included the Wells prediction rule (median adherence score=0.76 vs 0.59, p=0.002). This difference was even more pronounced when the analysis was limited to the CDSS intervention phase only (median adherence score=0.80 when Wells was used vs 0.60 when Wells was not used, p=0.001). For secondary outcomes, using both the D-dimer blood test (42.9% vs 55.7%, p=0.014) and CT pulmonary angiogram imaging (61.9% vs 75.4%, p=0.005) was lower during the CDSS intervention phase.

CONCLUSION

A clinical decision support intervention with an HCD improves some aspects of the diagnostic decision, such as the selection of diagnostic tests and the use of the Wells probabilistic prediction rule for PE.

Efficacy and Impact of a Multimodal Intervention on CT Pulmonary Angiography Ordering Behavior in the Emergency Department

OBJECTIVE

To evaluate the efficacy of a multimodal intervention in reducing CT pulmonary angiography (CTPA) overutilization in the evaluation of suspected pulmonary embolism in the emergency department (ED).

METHODS

Previous mixed-methods analysis of barriers to guideline-concordant CTPA ordering results was used to develop a provider-focused behavioral intervention consisting of a clinical decision support tool and an audit and feedback system at a multisite, tertiary academic network. The primary outcome (guideline concordance) and secondary outcomes (yield and CTPA and D-dimer order rates) were compared using a pre- and postintervention design. ED encounters for adult patients from July 5, 2017, to January 3, 2019, were included. Fisher's exact tests and statistical process control charts were used to compare the pre- and postintervention groups for each outcome.

RESULTS

Of the 201,912 ED patient visits evaluated, 3,587 included CTPA. Guideline concordance increased significantly after the intervention, from 66.9% to 77.5% (P < .001). CTPA order rate and D-dimer order rate also increased significantly, from 17.1 to 18.4 per 1,000 patients (P = .035) and 30.6 to 37.3 per 1,000 patients (P < .001), respectively. Percent yield showed no significant change (12.3% pre- versus 10.8% postintervention; P = .173). Statistical process control analysis showed sustained special-cause variation in the postintervention period for guideline concordance and D-dimer order rates, temporary special-cause variation for CTPA order rates, and no special-cause variation for percent yield.

CONCLUSION

Our success in increasing guideline concordance demonstrates the efficacy of a mixed-methods, human-centered approach to behavior change. Given that neither of the secondary outcomes improved, our results may demonstrate potential limitations to the guidelines directing the ordering of CTPA studies and D-dimer ordering.

Temporal Trends in the Use of Computed Tomographic Pulmonary Angiography for Suspected Pulmonary Embolism in the Emergency Department : A Retrospective Analysis

BACKGROUND

Recently, validated clinical decision rules have been developed that avoid unnecessary use of computed tomographic pulmonary angiography (CTPA) in patients with suspected pulmonary embolism (PE) in the emergency department (ED).

OBJECTIVE

To measure any resulting change in CTPA use for suspected PE.

DESIGN

Retrospective analysis.

SETTING

26 European EDs in 6 countries.

PATIENTS

Patients with CTPA performed for suspected PE in the ED during the first 7 days of each odd month between January 2015 and December 2019.

MEASUREMENTS

The primary end points were the CTPAs done for suspected PE in the ED and the number of PEs diagnosed in the ED each year adjusted to an annual census of 100 000 ED visits. Temporal trends were estimated using generalized linear mixed regression models.

RESULTS

8970 CTPAs were included (median age, 63 years; 56% female). Statistically significant temporal trends for more frequent use of CTPA (836 per 100 000 ED visits in 2015 vs. 1112 in 2019; P < 0.001), more diagnosed PEs (138 per 100 000 in 2015 vs. 164 in 2019; P = 0.028), a higher proportion of low-risk PEs (annual percent change [APC], 13.8% [95% CI, 2.6% to 30.1%]) with more ambulatory management (APC, 19.3% [CI, 4.1% to 45.1%]), and a lower proportion of intensive care unit admissions (APC, -8.9% [CI, -17.1% to -0.3%]) were observed.

LIMITATION

Data were limited to 7 days every 2 months.

CONCLUSION

Despite the recent validation of clinical decision rules to limit the use of CTPA, an increase in the CTPA rate along with more diagnosed PEs and especially low-risk PEs were instead observed.

PRIMARY FUNDING SOURCE

None specific for this study.

Nudging Health Care Providers' Adoption of Clinical Decision Support: Protocol for the User-Centered Development of a Behavioral Economics-Inspired Electronic Health Record Tool

BACKGROUND

The improvements in care resulting from clinical decision support (CDS) have been significantly limited by consistently low health care provider adoption. Health care provider attitudes toward CDS, specifically psychological and behavioral barriers, are not typically addressed during any stage of CDS development, although they represent an important barrier to adoption. Emerging evidence has shown the surprising power of using insights from the field of behavioral economics to address psychological and behavioral barriers. Nudges are formal applications of behavioral economics, defined as positive reinforcement and indirect suggestions that have a nonforced effect on decision-making.

OBJECTIVE

Our goal is to employ a user-centered design process to develop a CDS tool-the pulmonary embolism (PE) risk calculator-for PE risk stratification in the emergency department that incorporates a behavior theory-informed nudge to address identified behavioral barriers to use.

METHODS

All study activities took place at a large academic health system in the New York City metropolitan area. Our study used a user-centered and behavior theory-based approach to achieve the following two aims: (1) use mixed methods to identify health care provider barriers to the use of an active CDS tool for PE risk stratification and (2) develop a new CDS tool-the PE risk calculator-that addresses behavioral barriers to health care providers' adoption of CDS by incorporating nudges into the user interface. These aims were guided by the revised Observational Research Behavioral Information Technology model. A total of 50 clinicians who used the original version of the tool were surveyed with a quantitative instrument that we developed based on a behavior theory framework-the Capability-Opportunity-Motivation-Behavior framework. A semistructured interview guide was developed based on the survey responses. Inductive methods were used to analyze interview session notes and audio recordings from 12 interviews. Revised versions of the tool were developed that incorporated nudges.

RESULTS

Functional prototypes were developed by using Axure PRO (Axure Software Solutions) software and usability tested with end users in an iterative agile process (n=10). The tool was redesigned to address 4 identified major barriers to tool use; we included 2 nudges and a default. The 6-month pilot trial for the tool was launched on October 1, 2021.

CONCLUSIONS

Clinicians highlighted several important psychological and behavioral barriers to CDS use. Addressing these barriers, along with conducting traditional usability testing, facilitated the development of a tool with greater potential to transform clinical care. The tool will be tested in a prospective pilot trial.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/42653.

Vascular imaging of the lung: perspectives on current imaging methods

This commentary will discuss the use of advanced non-invasive imaging methodology for the pulmonary vascular system with special attention to a rubric for the imaging and clinical team to use for any particular clinical situation.

Automated Pulmonary Embolism Risk Assessment Using the Wells Criteria: Validation Study

Background

Computed tomography pulmonary angiography (CTPA) is frequently used in the emergency department (ED) for the diagnosis of pulmonary embolism (PE), while posing risk for contrast-induced nephropathy and radiation-induced malignancy.

Objective

We aimed to create an automated process to calculate the Wells score for pulmonary embolism for patients in the ED, which could potentially reduce unnecessary CTPA testing.

Methods

We designed an automated process using electronic health records data elements, including using a combinatorial keyword search method to query free-text fields, and calculated automated Wells scores for a sample of all adult ED encounters that resulted in a CTPA study for PE at 2 tertiary care hospitals in New York, over a 2-month period. To validate the automated process, the scores were compared to those derived from a 2-clinician chart review.

Results

A total of 202 ED encounters resulted in a completed CTPA to form the retrospective study cohort. Patients classified as “PE likely” by the automated process (126/202, 62%) had a PE prevalence of 15.9%, whereas those classified as “PE unlikely” (76/202, 38%; Wells score >4) had a PE prevalence of 7.9%. With respect to classification of the patient as “PE likely,” the automated process achieved an accuracy of 92.1% when compared with the chart review, with sensitivity, specificity, positive predictive value, and negative predictive value of 93%, 90.5%, 94.4%, and 88.2%, respectively.

Conclusions

This was a successful development and validation of an automated process using electronic health records data elements, including free-text fields, to classify risk for PE in ED visits.

Barriers to the Use of Clinical Decision Support for the Evaluation of Pulmonary Embolism: Qualitative Interview Study

BACKGROUND

Clinicians often disregard potentially beneficial clinical decision support (CDS).

OBJECTIVE

In this study, we sought to explore the psychological and behavioral barriers to the use of a CDS tool.

METHODS

We conducted a qualitative study involving emergency medicine physicians and physician assistants. A semistructured interview guide was created based on the Capability, Opportunity, and Motivation-Behavior model. Interviews focused on the barriers to the use of a CDS tool built based on Wells' criteria for pulmonary embolism to assist clinicians in establishing pretest probability of pulmonary embolism before imaging.

RESULTS

Interviews were conducted with 12 clinicians. Six barriers were identified, including (1) Bayesian reasoning, (2) fear of missing a pulmonary embolism, (3) time pressure or cognitive load, (4) gestalt includes Wells' criteria, (5) missed risk factors, and (6) social pressure.

CONCLUSIONS

Clinicians highlighted several important psychological and behavioral barriers to CDS use. Addressing these barriers will be paramount in developing CDS that can meet its potential to transform clinical care.

Suspected Acute Pulmonary Embolism: Gestalt, Scoring Systems, and Artificial Intelligence

Pulmonary embolism (PE) remains a diagnostic challenge in 2021. As the pathology is potentially fatal and signs and symptoms are nonspecific, further investigations are classically required. Based on the Bayesian approach, clinical probability became the keystone of the diagnostic strategy to rule out PE in the case of a negative testing. Several clinical probability assessment methods are validated: gestalt, the Wells score, or the revised Geneva score. While the debate persists as to the best way to assess clinical probability, its assessment allows for the good interpretation of the investigation results and therefore directs the correct diagnostic strategy. The wide availability of computed tomography pulmonary angiography (CTPA) resulted in a major increase in investigations with a moderate increase in diagnosis, without any notable improvement in patient outcomes. This leads to a new challenge for PE diagnosis which is the limitation of the number of testing for suspected PE. We review different strategies recently developed to achieve this goal. The last challenge concerns the implementation in clinical practice. Two approaches are developed: simplification of the strategies versus the use of digital support tools allowing more sophisticated strategies. Artificial intelligence with machine-learning algorithms will probably be a future tool to guide the physician in this complex approach concerning acute PE suspicion.

Physician choices in pulmonary embolism testing

BACKGROUND

Evidence-based guidelines advise excluding pulmonary embolism (PE) diagnosis using d-dimer in patients with a lower probability of PE. Emergency physicians frequently order computed tomography (CT) pulmonary angiography without d-dimer testing or when d-dimer is negative, which exposes patients to more risk than benefit. Our objective was to develop a conceptual framework explaining emergency physicians' test choices for PE.

METHODS

We conducted a qualitative study using in-depth interviews of emergency physicians in Canada. A nonmedical researcher conducted in-person interviews. Participants described how they would test simulated patients with symptoms of possible PE, answered a knowledge test and were interviewed on barriers to using evidence-based PE tests.

RESULTS

We interviewed 63 emergency physicians from 9 hospitals in 5 cities, across 3 provinces. We identified 8 domains: anxiety with PE, barriers to using the evidence (time, knowledge and patient), divergent views on evidence-based PE testing, inherent Wells score problems, the drive to obtain CT rather than to diagnose PE, gestalt estimation artificially inflating PE probability, subjective reasoning and cognitive biases supporting deviation from evidence-based tests and use of evidence-based testing to rule out PE in patients who are very unlikely to have PE. Choices for PE testing were influenced by the disease, environment, test qualities, physician and probability of PE.

INTERPRETATION

Analysis of structured interviews with emergency physicians provided a conceptual framework to explain how these physicians use tests for suspected PE. The data suggest 8 domains to address when implementing an evidence-based protocol to investigate PE.

Trends in Imaging for Suspected Pulmonary Embolism Across US Health Care Systems, 2004 to 2016

IMPORTANCE

In response to calls to reduce unnecessary diagnostic testing with computed tomographic pulmonary angiography (CTPA) for suspected pulmonary embolism (PE), there have been growing efforts to create and implement decision rules for PE testing. It is unclear if the use of advanced imaging tests for PE has diminished over time.

OBJECTIVE

To assess the use of advanced imaging tests, including chest computed tomography (CT) (ie, all chest CT except for CTPA), CTPA, and ventilation-perfusion (V/Q) scan, for PE from 2004 to 2016.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study of adults by age group (18-64 years and ≥65 years) enrolled in 7 US integrated and mixed-model health care systems. Joinpoint regression analysis was used to identify years with statistically significant changes in imaging rates and to calculate average annual percentage change (growth) from 2004 to 2007, 2008 to 2011, and 2012 to 2016. Analyses were conducted between June 11, 2019, and March 18, 2020.

MAIN OUTCOMES AND MEASURES

Rates of chest CT, CTPA, and V/Q scan by year and age, as well as annual change in rates over time.

RESULTS

Overall, 3.6 to 4.8 million enrollees were included each year of the study, for a total of 52 343 517 person-years of follow-up data. Adults aged 18 to 64 years accounted for 42 223 712 person-years (80.7%) and those 65 years or older accounted for 10 119 805 person-years (19.3%). Female enrollees accounted for 27 712 571 person-years (52.9%). From 2004 and 2016, chest CT use increased by 66.3% (average annual growth, 4.4% per year), CTPA use increased by 450.0% (average annual growth, 16.3% per year), and V/Q scan use decreased by 47.1% (decreasing by 4.9% per year). The use of CTPA increased most rapidly from 2004 to 2006 (44.6% in those aged 18-64 years and 43.9% in those ≥65 years), with ongoing rapid growth from 2006 to 2010 (annual growth, 19.8% in those aged 18-64 years and 18.3% in those ≥65 years) and persistent but slower growth in the most recent years (annual growth, 4.3% in those aged 18-64 years and 3.0% in those ≥65 years from 2010 to 2016). The use of V/Q scanning decreased steadily since 2004.

CONCLUSIONS AND RELEVANCE

From 2004 to 2016, rates of chest CT and CTPA for suspected PE continued to increase among adults but at a slower pace in more contemporary years. Efforts to combat overuse have not been completely successful as reflected by ongoing growth, rather than decline, of chest CT use. Whether the observed imaging use was appropriate or was associated with improved patient outcomes is unknown.

Diagnostic yield of computed tomographic pulmonary angiography for suspected pulmonary embolism varies across settings within a community-based health system

PURPOSE

The diagnostic yield of computed tomographic pulmonary angiography (CTPA) for pulmonary embolism varies in the literature, and very little data is available regarding community-based systems. This study evaluates the yield of CTPA for pulmonary embolism across a variety of patient care settings in a community-based healthcare system, providing relevant benchmarks for potential quality improvement efforts.

METHODS

This retrospective study included data collected from three sites within a single community-based healthcare system, including a tertiary care level 1 trauma center, an urban community hospital, and a suburban free-standing emergency department. CTPAs were identified by Current Procedural Terminology codes, and diagnoses of pulmonary embolism were identified via International Classification of Diseases codes. A total of 7850 CTPA studies met criteria for inclusion between January 1, 2012, and October 8, 2014.

RESULTS

Pulmonary embolism was found in 884 (11.3%) of the studies performed. Outpatients had a lower yield of pulmonary embolism (3.8%, p < 0.001) compared with inpatients (14.1%) and emergency department patients (10.7%, p < 0.001). Patients with diagnoses of deep vein thrombosis or neoplasm had increased incidence of pulmonary embolism when compared with patients without these diagnoses (p < 0.001 for both).

CONCLUSION

The overall yield of CTPA for pulmonary embolism in this community-based system was similar to that at academic centers. The yield was significantly lower in the outpatient setting compared with studies originating in the emergency department or inpatient setting.

High Scan Volume with Low Positive Scan Rate in Highest Utilizers: Computed Tomography Pulmonary Angiography in the Emergency Department

BACKGROUND

We examined utilization patterns and predictors of computed tomography pulmonary angiography (CTPA) results in the emergency department (ED).

OBJECTIVES

We retrospectively determined ED CTPA positive scan rate (PSR) among ED attendings based on a system that grouped attendings into scan quantity categories through >100.

METHODS

We manually reviewed all scans ordered in 2017 in EDs in a multisite medical system.

RESULTS

Of 10,032 ED CTPAs, 6168 were ordered by 153 ED attendings. Most attendings (123/153; 80%) ordered 60 or fewer scans with relatively high PSR (259/2927, PSR 8.8%; 95% confidence interval 7.8-9.9%). Of the ED attendings, 13 (3%) ordered more than 100 scans each (1981 scans; 32% of all scans), with PSR of 5.5% (95% confidence interval 4.5-6.5%).

CONCLUSION

Most ED attendings were low- to mid-volume utilizers of CTPA and had a relatively high PSR. However, the small percentage of attendings who ordered more than 100 scans each accounted for a large percentage of the total scan volume and had a relatively low PSR. These findings suggest that sharing of performance feedback and best practices in the highest utilizers could help to improve CTPA PSR in the ED.

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.

Predictors of Overtesting in Pulmonary Embolism Diagnosis

BACKGROUND

The benefits of computed tomography pulmonary angiography (CTPA) for pulmonary embolism (PE) diagnosis must be weighed against its risks, radiation-induced malignancy, and contrast-induced nephropathy. Appropriate use of CTPA can be assessed by monitoring yield, the percentage of tests positive for PE. We identify factors that are associated low CTPA yield, which may predict overtesting.

METHODS

This was a retrospective cohort study of six emergency departments between June 2014 and February 2017. The electronic health record was queried for CTPAs ordered for adult patients in the emergency department. We assessed the following patient factors: age, gender, body mass index, number of comorbidities, race, and ethnicity, provider factors: type (resident, fellow, attending, physician assistant) and environment factors: test time of day, season of visit, and crowdedness of the department.

RESULTS

A total of 14,782 CTPAs were reviewed, of which 1366 were found to be positive for PE, resulting in an overall CTPA yield of 9.24%. Provider type was not associated with a difference in yield. Testing was less likely to be positive in younger patients, females, those with lower body mass indexes and those identifying as Asian or Hispanic. Testing was also less likely to be positive when ordered during the overnight shift and during the winter and spring seasons.

CONCLUSION

Our study identified several patient and environmental factors associated with low CTPA yield suggesting potential targets for overtesting. Targeting education and clinical decision support to assist providers in these circumstances may meaningfully improve yields.

Higher Imaging Yield When Clinical Decision Support Is Used

OBJECTIVE

Increased utilization of CT pulmonary angiography (CTPA) for the evaluation of pulmonary embolism has been associated with decreasing diagnostic yields and rising concerns about the harms of unnecessary testing. The objective of this study was to determine whether clinical decision support (CDS) use would be associated with increased imaging yields after controlling for selection bias.

METHODS

We performed a retrospective cohort study in the emergency departments of two tertiary care hospitals of all CTPAs performed between August 2015 and September 2018. Providers ordering a CTPA are routed to an optional CDS tool, which allows them to use Wells' Criteria for pulmonary embolism. After propensity score matching, CTPA yield was calculated for the CDS-use and CDS-dismissal groups and stratified by provider type.

RESULTS

A total of 7,367 CTPAs were ordered during the study period. Of those, providers used the CDS tool in 2,568 (35%) cases and did not use the tool in 4,799 (65%) of cases. After propensity score matching, CTPA yield was 11.99% in the CDS-use group and 8.70% in the CDS-dismissal group (P < .001). Attending physicians, residents, and physician assistant CDS users demonstrated a 56.5% (P = .006), 38.7% (P = .01), and 16.7% (P = .03) increased yield compared with those who dismissed the tool, respectively.

DISCUSSION

Diagnostic yield was 38% higher for CTPAs when the provider used the CDS tool, after controlling for selection bias. Yields were higher for every provider type. Further research is needed to discover successful strategies to increase provider use of these important tools.

Retrospective Analysis of the Computed Tomography Pulmonary Angiogram Utilization Patterns in the Emergency Department

OBJECTIVES

Guidelines and high-quality studies recommend using clinical decision-making (CDM) tools over clinical gestalt when evaluating a patient for pulmonary embolism. The purpose of this study is to investigate our computed tomography pulmonary angiogram (CTPA) utilization patterns and identify causal factors.

METHODS

A retrospective cohort study of CTPA studies ordered by emergency physicians in January, April, July, and October 2017 was undertaken. All necessary information to categorize patients by Wells' score, revised Geneva score, and pulmonary embolism rule-out criteria (PERC) was collected. In addition, various bloodwork, chest radiograph, and computed tomography results were collected. This data was analysed by the Pearson chi-square test or Fisher's exact test for categorical data and independent-samples t test for continuous variables.

RESULTS

A total of 510 CTPA studies were performed, with a mean age was 61.6 and a 50.6% female population. 136 studies (26.7%) failed to appropriately follow any CDM tool. CDM tool failure rate was dependent on whether the study was ordered from a community (14.9%) or tertiary hospital (University of Alberta Hospital, 27.9% and Royal Alexandra Hospital, 24.6%) (P = .038). Of these 136 studies, 31 were low/moderate risk and the d-dimer was negative. The remainder were either PERC-negative or low/moderate risk without d-dimer performed. The cumulative positive pulmonary embolism rate was 12.5%. With utilization of a CDM tool, the positive pulmonary embolism rate was 15.0%, compared to 5.9% when using gestalt (P = .026).

CONCLUSIONS

This study confirms a high rate of CDM tool use failure, and a higher positive CTPA rate for CDM tools compared to clinical gestalt.

Development and Performance of the Pulmonary Embolism Result Forecast Model (PERFORM) for Computed Tomography Clinical Decision Support

IMPORTANCE

Pulmonary embolism (PE) is a life-threatening clinical problem, and computed tomographic imaging is the standard for diagnosis. Clinical decision support rules based on PE risk-scoring models have been developed to compute pretest probability but are underused and tend to underperform in practice, leading to persistent overuse of CT imaging for PE.

OBJECTIVE

To develop a machine learning model to generate a patient-specific risk score for PE by analyzing longitudinal clinical data as clinical decision support for patients referred for CT imaging for PE.

DESIGN, SETTING, AND PARTICIPANTS

In this diagnostic study, the proposed workflow for the machine learning model, the Pulmonary Embolism Result Forecast Model (PERFORM), transforms raw electronic medical record (EMR) data into temporal feature vectors and develops a decision analytical model targeted toward adult patients referred for CT imaging for PE. The model was tested on holdout patient EMR data from 2 large, academic medical practices. A total of 3397 annotated CT imaging examinations for PE from 3214 unique patients seen at Stanford University hospitals and clinics were used for training and validation. The models were externally validated on 240 unique patients seen at Duke University Medical Center. The comparison with clinical scoring systems was done on randomly selected 100 outpatient samples from Stanford University hospitals and clinics and 101 outpatient samples from Duke University Medical Center.

MAIN OUTCOMES AND MEASURES

Prediction performance of diagnosing acute PE was evaluated using ElasticNet, artificial neural networks, and other machine learning approaches on holdout data sets from both institutions, and performance of models was measured by area under the receiver operating characteristic curve (AUROC).

RESULTS

Of the 3214 patients included in the study, 1704 (53.0%) were women from Stanford University hospitals and clinics; mean (SD) age was 60.53 (19.43) years. The 240 patients from Duke University Medical Center used for validation included 132 women (55.0%); mean (SD) age was 70.2 (14.2) years. In the samples for clinical scoring system comparisons, the 100 outpatients from Stanford University hospitals and clinics included 67 women (67.0%); mean (SD) age was 57.74 (19.87) years, and the 101 patients from Duke University Medical Center included 59 women (58.4%); mean (SD) age was 73.06 (15.3) years. The best-performing model achieved an AUROC performance of predicting a positive PE study of 0.90 (95% CI, 0.87-0.91) on intrainstitutional holdout data with an AUROC of 0.71 (95% CI, 0.69-0.72) on an external data set from Duke University Medical Center; superior AUROC performance and cross-institutional generalization of the model of 0.81 (95% CI, 0.77-0.87) and 0.81 (95% CI, 0.73-0.82), respectively, were noted on holdout outpatient populations from both intrainstitutional and extrainstitutional data.

CONCLUSIONS AND RELEVANCE

The machine learning model, PERFORM, may consider multitudes of applicable patient-specific risk factors and dependencies to arrive at a PE risk prediction that generalizes to new population distributions. This approach might be used as an automated clinical decision-support tool for patients referred for CT PE imaging to improve CT use.

Baseline Performance of Real-World Clinical Practice Within a Statewide Emergency Medicine Quality Network: The Michigan Emergency Department Improvement Collaborative (MEDIC)

STUDY OBJECTIVE

Large-scale quality and performance measurement across unaffiliated hospitals is an important strategy to drive practice change. The Michigan Emergency Department Improvement Collaborative (MEDIC), established in 2015, has baseline performance data to identify practice variation across 15 diverse emergency departments (EDs) on key emergency care quality indicators.

METHODS

MEDIC is a unique physician-led partnership supported by a major third-party payer. Member sites contribute electronic health record data and trained abstractors add supplementary data for eligible cases. Quality measures include computed tomography (CT) appropriateness for minor head injury, using the Canadian CT Head Rule for adults and Pediatric Emergency Care Applied Network rules for children; chest radiograph use for children with asthma, bronchiolitis, and croup; and diagnostic yield of CTs for suspected pulmonary embolism. Baseline performance was established with statistical process control charts.

RESULTS

From June 1, 2016, to October 31, 2017, the MEDIC registry contained 1,124,227 ED visits, 23.2% for children (<18 years). Overall baseline performance included the following: 40.9% of adult patients with minor head injury (N=11,857) had appropriate CTs (site range 24.3% to 58.6%), 10.3% of pediatric minor head injury cases (N=11,183) exhibited CT overuse (range 5.8% to 16.8%), 38.1% of pediatric patients with a respiratory condition (N=18,190) received a chest radiograph (range 9.0% to 62.1%), and 8.7% of pulmonary embolism CT results (N=16,205) were positive (range 7.5% to 14.3%).

CONCLUSION

Performance varied greatly, with demonstrated opportunity for improvement. MEDIC provides a robust platform for emergency physician engagement across ED practice settings to improve care and is a model for other states.

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.

Increasing rate of pulmonary embolism diagnosed in hospitalized children in the United States from 2001 to 2014

Although rare in children, pulmonary embolism (PE) can cause significant morbidity and mortality. Overall rates of venous thromboembolism (VTE) are increasing in hospitalized children. By using the Pediatric Health Information System database, we evaluated incidence, treatment, and outcome of PE in children younger than age 18 years from 2001 to 2014. Demographic characteristics for those admitted with VTE alone and those admitted with PE were compared. Rates of PE by year were compared with the number of hospital and VTE admissions. Trends in medication use were analyzed. Over the period of the study, patients with PE made up 15.8% of VTE discharges. The overall rate of PE increased 200% (P < .001). Compared with all other age groups, adolescents (age 13-18 years) had the highest prevalence (55%; P < .001), the rate of which increased from 9.8 to 24.7 per 10 000 hospital discharges (152%; P < .001), and from 17.5 to 34.1 per 100 VTE discharges (95%; P < .001). Individuals with PE had a higher mortality (8.3% vs 6%; P < .001) and were less likely to have a complex chronic condition (58% vs 65%; P < .001) than those with VTE alone. However, PE mortality rates decreased over the time period studied. African American and Hispanic patients were more likely to experience recurrent PE than white patients (12% and 10.7% vs 8%; P = .002). During the study period, the use of unfractionated heparin decreased (P < .001), and the use of low molecular weight heparin increased (P < .001). Further research is required to determine what factors contribute to the higher rate of PE in adolescents and influence recurrence in African American and Hispanic patients.

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.

Improving Provider Adoption With Adaptive Clinical Decision Support Surveillance: An Observational Study

Background

Successful clinical decision support (CDS) tools can help use evidence-based medicine to effectively improve patient outcomes. However, the impact of these tools has been limited by low provider adoption due to overtriggering, leading to alert fatigue. We developed a tracking mechanism for monitoring trigger (percent of total visits for which the tool triggers) and adoption (percent of completed tools) rates of a complex CDS tool based on the Wells criteria for pulmonary embolism (PE).

Objective

We aimed to monitor and evaluate the adoption and trigger rates of the tool and assess whether ongoing tool modifications would improve adoption rates.

Methods

As part of a larger clinical trial, a CDS tool was developed using the Wells criteria to calculate pretest probability for PE at 2 tertiary centers’ emergency departments (EDs). The tool had multiple triggers: any order for D-dimer, computed tomography (CT) of the chest with intravenous contrast, CT pulmonary angiography (CTPA), ventilation-perfusion scan, or lower extremity Doppler ultrasound. A tracking dashboard was developed using Tableau to monitor real-time trigger and adoption rates. Based on initial low provider adoption rates of the tool, we conducted small focus groups with key ED providers to elicit barriers to tool use. We identified overtriggering of the tool for non-PE-related evaluations and inability to order CT testing for intermediate-risk patients. Thus, the tool was modified to allow CT testing for the intermediate-risk group and not to trigger for CT chest with intravenous contrast orders. A dialogue box, “Are you considering PE for this patient?” was added before the tool triggered to account for CTPAs ordered for aortic dissection evaluation.

Results

In the ED of tertiary center 1, 95,295 patients visited during the academic year. The tool triggered for an average of 509 patients per month (average trigger rate 2036/30,234, 6.73%) before the modifications, reducing to 423 patients per month (average trigger rate 1629/31,361, 5.22%). In the ED of tertiary center 2, 88,956 patients visited during the academic year, with the tool triggering for about 473 patients per month (average trigger rate 1892/29,706, 6.37%) before the modifications and for about 400 per month (average trigger rate 1534/30,006, 5.12%) afterward. The modifications resulted in a significant 4.5- and 3-fold increase in provider adoption rates in tertiary centers 1 and 2, respectively. The modifications increased the average monthly adoption rate from 23.20/360 (6.5%) tools to 81.60/280.20 (29.3%) tools and 46.60/318.80 (14.7%) tools to 111.20/263.40 (42.6%) tools in centers 1 and 2, respectively.

Conclusions

Close postimplementation monitoring of CDS tools may help improve provider adoption. Adaptive modifications based on user feedback may increase targeted CDS with lower trigger rates, reducing alert fatigue and increasing provider adoption. Iterative improvements and a postimplementation monitoring dashboard can significantly improve adoption rates.

Potential Effect of the Protecting Access to Medicare Act on Use of Advanced Diagnostic Imaging in the Emergency Department: An Analysis of the National Hospital Ambulatory Care Survey

Background Clinical decision support is increasingly used to enhance clinicians' exposure to established evidence and patient information during an episode of patient care. Pending legislation specifies clinical decision support before performing advanced imaging at emergency department (ED) visits. Purpose To estimate the volume of advanced imaging tests (CT and MRI) that would require use of clinical decision support to achieve Protecting Access to Medicare Act (PAMA) compliance in the ED. Materials and Methods A retrospective, cross-sectional analysis of ED visits was conducted by using data from the 2012-2015 National Hospital Ambulatory Care Survey. PAMA-related visits were identified by selecting the patient reasons for visit (RFVs) related to the eight clinical conditions. Results Among the adult ED visits, 26.7% (20 506 of 77 299, representing 113 000 000 visits across 4 years, or 28 000 000 visits annually) patients presented with a RFV consistent with a PAMA priority clinical area (PCA). Among visits in which a patient described an RFV code consistent with a PAMA PCA, up to 22.9% (4681 of 20 506; 95% confidence interval: 21.8%, 24.1%) patients underwent advanced imaging, translating to approximately 6 000 000 visits annually. Conclusion Protecting Access to Medicare Act legislation targets eight priority clinical areas, estimated to be prevalent among one in four adult emergency department visits. CT and/or MRI studies are performed during up to 23% of these visits. Depending on the particular clinical decision support systems selected within a health system, and how they are implemented, the potential volume of studies in which clinicians must interact with clinical decision support system may either exceed or fall short of these estimates. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Forman in this issue.

A Computerized Method for Measuring Computed Tomography Pulmonary Angiography Yield in the Emergency Department: Validation Study

Background

Use of computed tomography pulmonary angiography (CTPA) in the assessment of pulmonary embolism (PE) has markedly increased over the past two decades. While this technology has improved the accuracy of radiological testing for PE, CTPA also carries the risk of substantial iatrogenic harm. Each CTPA carries a 14% risk of contrast-induced nephropathy and a lifetime malignancy risk that can be as high as 2.76%. The appropriate use of CTPA can be estimated by monitoring the CTPA yield, the percentage of tests positive for PE. This is the first study to propose and validate a computerized method for measuring the CTPA yield in the emergency department (ED).

Objective

The objective of our study was to assess the validity of a novel computerized method of calculating the CTPA yield in the ED.

Methods

The electronic health record databases at two tertiary care academic hospitals were queried for CTPA orders completed in the ED over 1-month periods. These visits were linked with an inpatient admission with a discharge diagnosis of PE based on the International Classification of Diseases codes. The computerized the CTPA yield was calculated as the number of CTPA orders with an associated inpatient discharge diagnosis of PE divided by the total number of orders for completed CTPA. This computerized method was then validated by 2 independent reviewers performing a manual chart review, which included reading the free-text radiology reports for each CTPA.

Results

A total of 349 CTPA orders were completed during the 1-month periods at the two institutions. Of them, acute PE was diagnosed on CTPA in 28 studies, with a CTPA yield of 7.7%. The computerized method correctly identified 27 of 28 scans positive for PE. The one discordant scan was tied to a patient who was discharged directly from the ED and, as a result, never received an inpatient discharge diagnosis.

Conclusions

This is the first successful validation study of a computerized method for calculating the CTPA yield in the ED. This method for data extraction allows for an accurate determination of the CTPA yield and is more efficient than manual chart review. With this ability, health care systems can monitor the appropriate use of CTPA and the effect of interventions to reduce overuse and decrease preventable iatrogenic harm.

Diagnostic accuracy of the D-dimer in children

BACKGROUND

We sought to measure the diagnostic accuracy of D-dimer in children with suspected pulmonary embolism (PE).

METHODS

We queried our electronic medical record for quantitative D-dimer values obtained in all children ages 5-17 over 10 years in our 10-hospital system. Patients who had a D-dimer obtained in the evaluation of PE underwent supervised chart review to extract baseline demographics (age, sex, ethnicity), medical history, laboratory data and imaging results. PE was confirmed by imaging positive for deep vein thrombosis (DVT) or PE and excluded by imaging or no DVT or PE diagnosis within 90 days.

RESULTS

Over a 10-year period, we identified 13 792 orders for D-dimer testing in 2554 unique patients. Chart review indicated that 526 (20.6%) unique patients had D-dimer testing performed in the evaluation of PE (Cohen's kappa=0.95, 95% CI 0.85 to 1.0). Most D-dimers (465/526, 88%) were ordered in children aged >12 years. Of these 526 children, 34 (6.4%, 95% CI) had a criterion standard positive for new or recurrent PE. The mean D-dimer value was 2104±1394 ng/mL in the 34/34 PE+ children and 586±962 ng/mL in PE- children with a sensitivity of 34/34 (100%, 89% to 100%) and a specificity of 290/492 (58%, 54% to 63%). The area under the receiver operating characteristic curve was 0.90 ((0.9)87-0.94).

CONCLUSIONS

D-dimer is currently ordered in children for suspected PE in the emergency care setting, mostly in teenagers. The observed lower limit 95% CIs of 89% and 54% for diagnostic sensitivity and the specificity, respectively, suggest if used in patients with low-clinical probability, a normal D-dimer can safely exclude PE in children.

Comparison of the age-adjusted and clinical probability-adjusted D-dimer to exclude pulmonary embolism in the ED

BACKGROUND

Diagnosing pulmonary embolism (PE) in the emergency department (ED) can be challenging because its signs and symptoms are non-specific.

OBJECTIVE

We compared the efficacy and safety of using age-adjusted D-dimer interpretation, clinical probability-adjusted D-dimer interpretation and standard D-dimer approach to exclude PE in ED patients.

DESIGN/METHODS

We performed a health records review at two emergency departments over a two-year period. We reviewed all cases where patients had a D-dimer ordered to test for PE or underwent CT or VQ scanning for PE. PE was considered to be present during the emergency department visit if PE was diagnosed on CT or VQ (subsegmental level or above), or if the patient was subsequently found to have PE or deep vein thrombosis during the next 30 days. We applied the three D-dimer approaches to the low and moderate probability patients. The primary outcome was exclusion of PE with each rule. Secondary objective was to estimate the negative predictive value (NPV) for each rule.

RESULTS

1163 emergency patients were tested for PE and 1075 patients were eligible for inclusion in our analysis. PE was excluded in 70.4% (95% CI 67.6-73.0%), 80.3% (95% CI 77.9-82.6%) and 68.9%; (95% CI 65.7-71.3%) with the age-adjusted, clinical probability-adjusted and standard D-dimer approach. The NPVs were 99.7% (95% CI 99.0-99.9%), 99.1% (95% CI 98.3-99.5%) and 100% (95% CI 99.4-100.0%) respectively.

CONCLUSION

The clinical probability-adjusted rule appears to exclude PE in a greater proportion of patients, with a very small reduction in the negative predictive value.

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.

Interventions to Reduce the Overuse of Imaging for Pulmonary Embolism: A Systematic Review

BACKGROUND

Imaging use in the diagnostic workup of pulmonary embolism (PE) has increased markedly in the last 2 decades. Low PE prevalence and diagnostic yields suggest a significant problem of overuse.

PURPOSE

The purpose of this systematic review is to summarize the evidence associated with the interventions aimed at reducing the overuse of imaging in the diagnostic workup of PE in the emergency department and hospital wards.

DATA SOURCES

PubMed, MEDLINE, Embase, and EBM Reviews from 1998 to March 28, 2017.

STUDY SELECTION

Experimental and observational studies were included. The types of interventions, their efficacy and safety, the impact on healthcare costs, the facilitators, and barriers to their implementation were assessed.

DATA SYNTHESIS

Seventeen studies were included assessing clinical decision support (CDS), educational interventions, performance and feedback reports (PFRs), and institutional policy. CDS impact was most comprehensively documented. It was associated with a reduction in imaging use, ranging from 8.3% to 25.4%, and an increase in diagnostic yield, ranging from 3.4% to 4.4%. The combined implementation of a CDS and PFR resulted in a modest but significant increase in the adherence to guidelines. Few studies appraised the safety of interventions. There was a lack of evidence concerning economic aspects, facilitators, and barriers.

CONCLUSIONS

A combined implementation of an electronic CDS and PFRs is more effective than purely educational or policy interventions, although evidence is limited. Future studies of high-methodological quality would strengthen the evidence concerning their efficacy, safety, facilitators, and barriers.

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.

Does the Incidence and Mortality of Pulmonary Thromboembolism Change Over the Years?

OBJECTIVES

In the last 20 years, with the use of computed tomography (CT) angiography, the number of patients diagnosed with pulmonary thromboembolism (PTE) has increased. At the same time, data show that pulmonary embolism mortality has also reduced in this duration.

MATERIAL AND METHODS

In this study, we analyzed records of patients with PTE (using ICD's) in the hospital automation system from 2001 to 2013. Data regarding age, sex, date of diagnosis, diagnosis of cancer, hemodynamic status, initial and maintenance treatment, hospital length of stay, and hospital mortality were recorded. Primary endpoints of the study were hospital length of stay and all-cause hospital mortality.

RESULTS

The total number of patients included in the study was 1185. The median age was 61 years in 2001 and 71 years in 2013. The number of patients who were diagnosed using CT increased from 10% to 92.8%. Between 2001 and 2013, the number of patients diagnosed with PTE increased, and of all patients with PTE, 13.7% was diagnosed in 2009. The hospital length of stay of 13 days declined to 9 days. The use of a vena cava filter in 2007 was 1.1% and that in 2013 was 4.6%. Mortality rate was 15%, however hospital mortality did not significantly differ over the years but varied between 9.4% and 18.8%. Increased use of thrombolytics in patients with massive PTE has been observed over the years. Massive PTE ratio in 2006 was 8.5% and thrombolytic use was 5.8%, however in 2013, these ratios were 2.6%, 6% respectively (p=0.017).

CONCLUSION

Finally, despite the increased number of patients diagnosed with PTE over the years, the mortality rate was not observed to have changed from 2001 to 2013.

Creation of a simple natural language processing tool to support an imaging utilization quality dashboard

BACKGROUND

Testing for venous thromboembolism (VTE) is associated with cost and risk to patients (e.g. radiation). To assess the appropriateness of imaging utilization at the provider level, it is important to know that provider's diagnostic yield (percentage of tests positive for the diagnostic entity of interest). However, determining diagnostic yield typically requires either time-consuming, manual review of radiology reports or the use of complex and/or proprietary natural language processing software.

OBJECTIVES

The objectives of this study were twofold: 1) to develop and implement a simple, user-configurable, and open-source natural language processing tool to classify radiology reports with high accuracy and 2) to use the results of the tool to design a provider-specific VTE imaging dashboard, consisting of both utilization rate and diagnostic yield.

METHODS

Two physicians reviewed a training set of 400 lower extremity ultrasound (UTZ) and computed tomography pulmonary angiogram (CTPA) reports to understand the language used in VTE-positive and VTE-negative reports. The insights from this review informed the arguments to the five modifiable parameters of the NLP tool. A validation set of 2,000 studies was then independently classified by the reviewers and by the tool; the classifications were compared and the performance of the tool was calculated.

RESULTS

The tool was highly accurate in classifying the presence and absence of VTE for both the UTZ (sensitivity 95.7%; 95% CI 91.5-99.8, specificity 100%; 95% CI 100-100) and CTPA reports (sensitivity 97.1%; 95% CI 94.3-99.9, specificity 98.6%; 95% CI 97.8-99.4). The diagnostic yield was then calculated at the individual provider level and the imaging dashboard was created.

CONCLUSIONS

We have created a novel NLP tool designed for users without a background in computer programming, which has been used to classify venous thromboembolism reports with a high degree of accuracy. The tool is open-source and available for download at http://iturrate.com/simpleNLP. Results obtained using this tool can be applied to enhance quality by presenting information about utilization and yield to providers via an imaging dashboard.

RESPECT-ED: Rates of Pulmonary Emboli (PE) and Sub-Segmental PE with Modern Computed Tomographic Pulmonary Angiograms in Emergency Departments: A Multi-Center Observational Study Finds Significant Yield Variation, Uncorrelated with Use or Small PE Rates

INTRODUCTION

Overuse of CT Pulmonary Angiograms (CTPA) for diagnosing pulmonary embolism (PE), particularly in Emergency Departments (ED), is considered problematic. Marked variations in positive CTPA rates are reported, with American 4-10% yields driving most concerns. Higher resolution CTPA may increase sub-segmental PE (SSPE) diagnoses, which may be up to 40% false positive. Excessive use and false positives could increase harm vs. benefit. These issues have not been systematically examined outside America.

AIMS

To describe current yield variation and CTPA utilisation in Australasian ED, exploring potential factors correlated with variation.

METHODS

A retrospective multi-centre review of consecutive ED-ordered CTPA using standard radiology reports. ED CTPA report data were inputted onto preformatted data-sheets. The primary outcome was site level yield, analysed both intra-site and against a nominated 15.3% yield. Factors potentially associated with yield were assessed for correlation.

RESULTS

Fourteen radiology departments (15 ED) provided 7077 CTPA data (94% ≥64-slice CT); PE were reported in 1028 (yield 14.6% (95%CI 13.8-15.4%; range 9.3-25.3%; site variation p <0.0001) with four sites significantly below and one above the 15.3% target. Admissions, CTPA usage, PE diagnosis rates and size of PE were uncorrelated with yield. Large PE (≥lobar) were 55% (CI: 52.1-58.2%) and SSPE 8.8% (CI: 7.1-10.5%) of positive scans. CTPA usage (0.2-1.5% adult attendances) was correlated (p<0.006) with PE diagnosis but not SSPE: large PE proportions.

DISCUSSION/ CONCLUSIONS

We found significant intra-site CTPA yield variation within Australasia. Yield was not clearly correlated with CTPA usage or increased small PE rates. Both SSPE and large PE rates were similar to higher yield historical cohorts. CTPA use was considerably below USA 2.5-3% rates. Higher CTPA utilisation was positively correlated with PE diagnoses, but without evidence of increased proportions of small PE. This suggests that increased diagnoses seem to be of clinically relevant sized PE.

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.