CT Pulmonary Angiography: Using Decision Rules in the Emergency Department

Diagnostic Yield, Radiation Exposure, and the Role of Clinical Decision Rules to Limit Computed Tomographic Pulmonary Angiography-Associated Complications

OBJECTIVES

Computed tomographic pulmonary angiography (CT-PA) is associated with significant cost, contrast, and radiation exposure. Clinical decision rules (CDRs) reduce the need for diagnostic imaging; however, their utility in the medical intensive care unit (MICU) remains unknown. We explored the diagnostic yield and complications associated with CT-PA (radiation exposure and contrast-induced acute kidney injury [AKI]) while investigating the efficacy of CDRs to reduce unnecessary testing.

METHODS

All CT-PAs performed in an academic MICU for 4 years were retrospectively reviewed. The Wells and revised Geneva scores (CDRs) and radiation dose per CT-PA were calculated, and the incidence of post-CT-PA AKI was recorded.

RESULTS

A total of 439 studies were analyzed; the diagnostic yield was 11% (48 PEs). Positive CT-PAs were associated with a higher Wells score (5.8 versus 3.2, P < 0.001), but similar revised Geneva scores (6.4 versus 6.0, P = 0.32). A Wells score of ≥4 had a positive likelihood ratio of 2.1 with a negative predictive value of 98.2. More than half (88.9%) of patients with a Wells score of ≤4 developed an AKI, with 55.6% of those having recovery of renal function.

CONCLUSIONS

There is overutilization of CT-PA in the MICU. The Wells score retains its negative predictive value in critically ill adult patients and may aid to limit radiation exposure and contrast-induced AKI in MICU.

Diagnostic Blood Biomarkers for Acute Pulmonary Embolism: A Systematic Review

(1) Background: The current diagnostic algorithm for acute pulmonary embolism (PE) is associated with the overuse of CT pulmonary angiography (CTPA). An additional highly specific blood test could potentially lower the proportion of patients with suspected PE that require CTPA. The aim was to summarize the literature on the diagnostic performance of biomarkers of patients admitted to an emergency department with suspected acute PE. (2) Methods: Medline and Embase databases were searched from 1995 to the present. The study selection process, data extraction, and risk of bias assessment were conducted by two reviewers. Eligibility criteria accepted all blood biomarkers except D-dimer, and CTPA was used as the reference standard. Qualitative data synthesis was performed. (3) Results: Of the 8448 identified records, only 6 were included. Eight blood biomarkers were identified, of which, three were investigated in two separate studies. Red distribution width and mean platelet volume were reported to have a specificity of ≥ 90% in one study, although these findings were not confirmed by other studies. The majority of the studies contained a high risk of selection bias. (4) Conclusions: The modest findings and the uncertain validity of the included studies suggest that none of the biomarkers identified in this systematic review have the potential to improve the current diagnostic algorithm for acute PE by reducing the overuse of CTPA.

How Tasmanian Emergency Departments 'Choose Wisely' When Investigating Suspected Pulmonary Embolism

Overuse of computed tomography pulmonary angiograms (CTPAs) for diagnosis of pulmonary embolism (PE) has been recognised as an issue for over ten years, with Choosing Wisely Australia recommending that CTPAs only be ordered if indicated by a clinical practice guideline (CPG). This study aimed to explore the use of evidence-based practice within regional Tasmanian emergency departments in relation to CTPA orders by determining whether CTPAs were ordered in accordance with validated CPGs. We conducted a retrospective medical record review of all patients who underwent CTPA across all public emergency departments in Tasmania between 1 August 2018 and 31 December 2019 inclusive. Data from 2758 CTPAs across four emergency departments were included. PE was reported in 343 (12.4%) of CTPAs conducted, with yield ranging from 8.2% to 16.1% between the four sites. Overall, 52.1% of participants had neither a CPG documented, nor a D-dimer conducted before their scan. A CPG was documented before 11.8% of scans, while D-dimer was conducted before 43% of CTPAs. The findings presented in this study indicate that Tasmanian emergency departments are not consistently 'Choosing Wisely' when investigating PE. Further research is required to identify explanations for these findings.

Application of the pulmonary embolism rule-out criteria (PERC rule) and age-adjusted D-Dimer in patients undergoing computed tomography pulmonary angiography for diagnosis of pulmonary embolism

Background

Diagnosis of pulmonary embolism (PE) constitutes a challenge for practitioners. Current practice involves use of pre-test probability prediction rules. Several strategies to optimize this process have been explored.

Objectives

To explore whether application of the pulmonary embolism rule-out criteria (PERC rule) and age-adjusted D-dimer (DD) would have reduced the number of computed tomography pulmonary angiography (CTPA) examinations performed in patients with suspected PE.

Methods

A retrospective cross-sectional study of adult patients taken for CTPA under suspicion of PE in 2018 and 2020. The PERC rule and age-adjusted DD were applied. The number of cases without indications for imaging studies was estimated and the operational characteristics for diagnosis of PE were calculated.

Results

302 patients were included. PE was diagnosed in 29.8%. Only 27.2% of 'not probable' cases according to the Wells criteria had D-dimer assays. Age adjustment would have reduced tomography use by 11.1%, with an AUC of 0.5. The PERC rule would have reduced use by 7%, with an AUC of 0.72.

Conclusions

Application of age-adjusted D-dimer and the PERC rule to patients taken for CTPA because of suspected PE seems to reduce the number of indications for the procedure.

Diagnosing Pulmonary Embolism With Computed Tomography Pulmonary Angiography: Diagnostic Accuracy of a Reduced Scan Range

PURPOSE

Computed tomography pulmonary angiography (CT-PA) is frequently used in the diagnostic workup of pulmonary embolism (PE), even in highly radiosensitive patient populations. This study aims to assess CT-PA with reduced z -axis coverage (compared with a standard scan range covering the entire lung) for its sensitivity for detecting PE and its potential to reduce the radiation dose.

MATERIALS AND METHODS

We retrospectively analyzed 602 consecutive CT-PA scans with definite or possible PE reported. A reduced scan range was defined based on the topogram, where the cranial slice was set at the top of the aortic arch and the caudal slice at the top of the lower hemidiaphragm. Locations of emboli in relation to the reduced scan range were recorded.

RESULTS

We included 513 CT-PA scans with definite acute PE in statistical analysis. Patients' median age was 66 (52 to 77) years, 46% were female. Median dose length product was 270.8 (111.3 to 503.9) mGy*cm. Comparing the original and reduced scan ranges, the mean scan length was significantly reduced by 48.0±8.6% (26.8±3.0 vs. 13.9±2.6 cm, P <0.001). Single emboli outside the reduced range in addition to emboli within were found in 15 scans (2.9%), while only 1 scan (0.2%) had an embolus outside the reduced range and none within it. The resulting sensitivity of CT-PA with reduced scan range was 99.81% (95% confidence interval: 98.74%-99.99%) for detecting any PE.

CONCLUSION

A reduced scan length in CT-PA, as defined above, would substantially decrease radiation dose while maintaining diagnostic accuracy for detecting PE.

Use of Computed Tomography Pulmonary Angiography in Emergency Departments: A Literature Review

Computed tomography pulmonary angiography (CTPA) has become the most widely used technique for diagnosis or exclusion of a pulmonary embolism (PE). It has been suggested that overuse of this imaging type may be prevalent, especially in emergency departments (EDs). The purpose of this literature review was to explore the use of CTPAs in EDs worldwide. A review following PRISMA guidelines was completed, with research published between September 2010 and August 2020 included. Five key topics emerged: use of CTPAs; explanations for overuse; use of D-dimer; variability in ordering practices between clinicians; and strategies to reduce overuse. This review found that CTPAs continue to be overused in EDs, leading to superfluous risks to patients. Published studies identify that while clinical practice guidelines (CPGs) have a strong effect on reducing unnecessary CTPAs with no significantly increased risk of missed diagnosis, the adoption of these tools by ED clinicians has remained low. This literature review highlights the need for further research into why CTPAs continue to be overused within EDs and why clinicians are hesitant to use CPGs in the clinical setting. Moreover, investigations into other potential strategies that may combat the overuse of this diagnostic tool are essential to reduce potential harm.

Diagnosing pulmonary thromboembolism: Concerns and controversies

Pulmonary thromboembolism (PTE) is an important cause of mortality/morbidity even today despite advancement in clinical understanding as well as diagnostic facilities. Clinical diagnosis of PTE is often challenging because of nonspecific sign/symptoms. Adherence to clinical decision-making protocols and appropriate use of diagnostic modalities like computed tomography pulmonary angiography can resolve the diagnostic dilemma in most cases and help in the overall management of PTE. This article deals with various concerns as well as controversies surrounding accurate diagnosis of PTE as on date.

Utilization of serum D-dimer assays prior to computed tomography pulmonary angiography scans in the diagnosis of pulmonary embolism among emergency department physicians: a retrospective observational study

Background

A variety of evidence-based algorithms and decision rules using D-Dimer testing have been proposed as instruments to allow physicians to safely rule out a pulmonary embolism (PE) in low-risk patients.

Objective

To describe the prevalence of D-Dimer utilization among emergency department (ED) physicians and its impact on positive yields and utilization rates of Computed Tomography Pulmonary Angiography (CTPA).

Methods

Data was collected on all CTPA studies ordered by ED physicians at three sites during a 2-year period. Using a chi-square test, we compared the diagnostic yield for those patients who had a D-Dimer prior to their CTPA and those who did not. Secondary analysis was done to examine the impact of D-Dimer testing prior to CTPA on individual physician diagnostic yield or utilization rate.

Results

A total of 2811 CTPAs were included in the analysis. Of these, 964 CTPAs (34.3%) were ordered without a D-Dimer, and 343 (18.7%) underwent a CTPA despite a negative D-Dimer. Those CTPAs preceded by a D-Dimer showed no significant difference in positive yields when compared to those ordered without a D-Dimer (9.9% versus 11.3%, p = 0.26). At the individual physician level, no statistically significant relationship was found between D-Dimer utilization and CTPA utilization rate or diagnostic yield.

Conclusion

This study provides evidence of suboptimal adherence to guidelines in terms of D-Dimer screening prior to CTPA, and forgoing CTPAs in patients with negative D-Dimers. However, the lack of a positive impact of D-Dimer testing on either CTPA diagnostic yield or utilization rate is indicative of issues relating to the high false-positive rates associated with D-Dimer screening.

Feasibility of a quality improvement project to increase adherence to evidence-based pulmonary embolism diagnosis in the emergency department

Background

Many evidence-based clinical decision tools are available for the diagnosis of pulmonary embolism (PE). However, these clinical decision tools have had suboptimal uptake in the everyday clinical practice in emergency departments (EDs), despite numerous implementation efforts. We aimed to test the feasibility of a multi-faceted intervention to implement an evidence-based PE diagnosis protocol.

Methods

We conducted an interrupted time series study in three EDs in Ontario, Canada. We enrolled consecutive adult patients accessing the ED with suspected PE from January 1, 2018, to February 28, 2020. Components of the intervention were as follows: clinical leadership endorsement, a new pathway for PE testing, physician education, personalized confidential physician feedback, and collection of patient outcome information. The intervention was implemented in November 2019. We identified six criteria for defining the feasibility outcome: successful implementation of the intervention in at least two of the three sites, capturing data on ≥ 80% of all CTPAs ordered in the EDs, timely access to electronic data, rapid manual data extraction with feedback preparation before the end of the month ≥ 80% of the time, and time required for manual data extraction and feedback preparation ≤ 2 days per week in total.

Results

The intervention was successfully implemented in two out of three sites. A total of 5094 and 899 patients were tested for PE in the period before and after the intervention, respectively. We captured data from 90% of CTPAs ordered in the EDs, and we accessed the required electronic data. The manual data extraction and individual emergency physician audit and feedback were consistently finalized before the end of each month. The time required for manual data extraction and feedback preparation was ≤ 2 days per week (14 h).

Conclusions

We proved the feasibility of implementing an evidence-based PE diagnosis protocol in two EDs. We were not successful implementing the protocol in the third ED.

Registration

The study was not registered.

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.

Pulmonary embolism rule out: positivity and factors affecting the yield of CT angiography

OBJECTIVE

CT pulmonary angiography (CTPA) is one of the most commonly ordered CT imaging tests. It is often believed to be overutilised with few recent studies showing a yield of less than 2%. This study aimed to determine the overall positivity rate of CTPA examinations and understand the factors that affect the yield of the CTPA examination.

METHODS

We retrospectively analysed 2713 patients who received the CTPA exam between 2016 and 2018. Type of study ordered (CTPA chest or CTPA chest with abdomen and pelvis CT), patient location (emergency department (ED), outpatient, inpatient, intensive care unit (ICU)) and patient characteristics-age, sex and body mass index (BMI) were recorded. A logistic regression analysis was performed to determine what factors affect the positivity rate of CT scans for pulmonary embolism (PE).

RESULTS

With 296 positive test results, the overall CTPA positivity was 10.9%. Male sex was associated with higher CTPA positivity, gender difference was maximum in 18-year to 35-year age group. Overweight and obese patients had significantly higher positivity as compared with BMI<25 (p<0.05). Higher positivity rate was seen in the BMI 25-40 group (11.9%) as compared with BMI>40 (10.1%) (p<0.05). Significant difference (p<0.001) was also found in CTPA examination yield from ICU (15.3%) versus inpatients (other than ICU) (12.4%) versus ED (9.6%), and outpatients (8.5%). The difference in CTPA yield based on the type of CT order (CTPA chest vs CTPA chest with CT abdomen and pelvis), patient's age and sex was not significant.

CONCLUSION

CTPA yield of 10.9% in this study is comparable to acceptable positivity rate for the USA and is higher than recent studies showing positivity of <2%. Patient characteristics like obesity and ICU or inpatient location are associated with higher rate of CT positivity.

Variability in practice patterns among emergency physicians in the evaluation of patients with a suspected diagnosis of pulmonary embolism

PURPOSE

To describe the inter-physician variability in the utilisation rate and diagnostic yield of computed tomography pulmonary angiography (CTPA) among a group of emergency department (ED) physicians working in a similar clinical environment.

METHODS

We collected data on all CTPA studies ordered by ED physicians at three affiliated sites during a 2-year period between January 1, 2016, and December 31, 2017. For each physician, we calculated individual CTPA utilisation rate (total number of CTPAs ordered per 1000 ED visits) and diagnostic yield (percentage of CTPAs that were positive for PE). Additional analysis was carried out in order to identify the highest orderers of CTPA and their diagnostic yield.

RESULTS

Seventy-seven ED physicians who collectively ordered a total of 2788 CTPAs were included in the study. Utilisation rates ranged from 1.1 to 22.2 CTPA per 1000 ED visits (median: 5.2 CTPA/1000 ED visits; 25%ile: 3.6 CTPA/1000 ED visits; 75%ile: 7.9 CTPA/1000 ED visits) and the CTPA diagnostic yields ranged from 0% to 33% (median: 9.1%; 25%ile: 5.2%; 75%ile: 16.1%). Those physicians in the lower quartile for ordering rate had a higher mean diagnostic yield when compared to the higher quartiles.

CONCLUSION

The findings of this study demonstrate variability in CTPA ordering patterns and diagnostic yields among physicians working within the same clinical environment. There is some suggestion that those physicians who order disproportionately higher numbers of CTPAs have lower diagnostic yields.

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.

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.

Automated Pulmonary Embolism Risk Classification and Guideline Adherence for Computed Tomography Pulmonary Angiography Ordering

BACKGROUND

The assessment of clinical guideline adherence for the evaluation of pulmonary embolism (PE) via computed tomography pulmonary angiography (CTPA) currently requires either labor-intensive, retrospective chart review or prospective collection of PE risk scores at the time of CTPA order. The recording of clinical data in a structured manner in the electronic health record (EHR) may make it possible to automate the calculation of a patient's PE risk classification and determine whether the CTPA order was guideline concordant.

OBJECTIVES

The objective of this study was to measure the performance of automated, structured data-only versions of the Wells and revised Geneva risk scores in emergency department (ED) encounters during which a CTPA was ordered. The hypothesis was that such an automated method would classify a patient's PE risk with high accuracy compared to manual chart review.

METHODS

We developed automated, structured data-only versions of the Wells and revised Geneva risk scores to classify 212 ED encounters during which a CTPA was performed as "PE likely" or "PE unlikely." We then combined these classifications with D-dimer ordering data to assess each encounter as guideline concordant or discordant. The accuracy of these automated classifications and assessments of guideline concordance were determined by comparing them to classifications and concordance based on the complete Wells and revised Geneva scores derived via abstractor manual chart review.

RESULTS

The automatically derived Wells and revised Geneva risk classifications were 91.5 and 92% accurate compared to the manually determined classifications, respectively. There was no statistically significant difference between guideline adherence calculated by the automated scores compared to manual chart review (Wells, 70.8% vs. 75%, p = 0.33; revised Geneva, 65.6% vs. 66%, p = 0.92).

CONCLUSION

The Wells and revised Geneva score risk classifications can be approximated with high accuracy using automated extraction of structured EHR data elements in patients who received a CTPA. Combining these automated scores with D-dimer ordering data allows for the automated assessment of clinical guideline adherence for CTPA ordering in the ED, without the burden of manual chart review.

Overuse and underuse of pulmonary CT angiography in patients with suspected pulmonary embolism

Background: The aim of the present study was to evaluate the utilization and diagnostic yields of CT pulmonary angiography (CTPA)using the Revised Geneva score and Wells’ criteria, in patients with suspected pulmonary embolism (PE).

Methods: One hundred and twelve adult patients underwent CTPA for suspected PE were participated in this study. The outcome was positive or negative CTPA for PE. Revised Geneva and Wells’ scores were calculated. The relationship between the results obtained rom these two scores and the available risk factors were compared. Descriptive analysis such as frequency and mean as well as analytical statistics including chi-square were done. The data analysis was performed using SPSS (v. 22).

Results: In this study, according to the Wells’ criteria calculated for the patients, 33.9% of the patients had low clinical, 56.3% intermediate and 9.8% high clinical probability. Among the 11 high clinical patients, 9(81.8%) were CTPA positive. Based on the revised Geneva score, 65 patients (58%) had low clinical, 36 (32.1%) intermediate and 11(9.8%) high clinical probability. Among the 1 high clinical patients, 8 were CTPA positive. Positive predictive value of the low clinical patients based on Wells’ criteria and the revised Geneva score was 18.4% and 30.8%, respectively. Also, positive predictive value for high clinical probability of Wells’ criteria and the revised Geneva score was 81.8% and 72.8% respectively.

Conclusion: Under/overuse of CTPA in diagnosing PTE is a common problem especially in university hospitals. It is possible to avoid unnecessary CTPA requests using scholarly investigations and more accurate clinical risk assessments.

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.

Qualitative Study to Understand Ordering of CT Angiography to Diagnose Pulmonary Embolism in the Emergency Room Setting

PURPOSE

To better understand the decision making behind the ordering of CT pulmonary angiography (CTPA) for the diagnosis of pulmonary embolism (PE) in the emergency department.

METHODS

We conducted semistructured interviews with our institution's emergency medicine (EM) providers and radiologists who read CTPAs performed in the emergency department. We employed the Theoretical Domains Framework-a formal, structured approach used to better understand the motivations and beliefs of physicians surrounding a complex medical decision making-to categorize the themes that arose from our interviews.

RESULTS

EM providers were identified as the main drivers of CTPA ordering. Both EM and radiologist groups perceived the radiologist's role as more limited. Experience- and gestalt-based heuristics were the most important factors driving this decision and more important, in many cases, than established algorithms for CTPA ordering. There were contrasting views on the value of d-dimer in the suspected PE workup, with EM providers finding this test less useful than radiologists. EM provider and radiologist suggestions for improving the appropriateness of CTPA ordering consisted of making this process more arduous and incorporating d-dimer tests and prediction rules into a decision support tool.

CONCLUSION

EM providers were the main drivers of CTPA ordering, and there was a marginalized role for the radiologist. Experience- and gestalt-based heuristics were the main influencers of CTPA ordering. Our findings suggest that a more nuanced intervention than simply including a d-dimer and a prediction score in each preimaging workup may be necessary to curb overordering of CTPA in patients suspected of PE.

An Observational Study of Dyspnea in Emergency Departments: The Asia, Australia, and New Zealand Dyspnea in Emergency Departments Study (AANZDEM)

OBJECTIVES

The objective was to describe the epidemiology of dyspnea presenting to emergency departments (EDs) in the Asia-Pacific region, to understand how it is investigated and treated and its outcome.

METHODS

Prospective interrupted time series cohort study conducted at three time points in EDs in Australia, New Zealand, Singapore, Hong Kong, and Malaysia of adult patients presenting to the ED with dyspnea as a main symptom. Data were collected over three 72-hour periods and included demographics, comorbidities, mode of arrival, usual medications, prehospital treatment, initial assessment, ED investigations, treatment in the ED, ED diagnosis, disposition from ED, in-hospital outcome, and final hospital diagnosis. The primary outcomes of interest are the epidemiology, investigation, treatment, and outcome of patients presenting to ED with dyspnea.

RESULTS

A total of 3,044 patients were studied. Patients with dyspnea made up 5.2% (3,105/60,059, 95% confidence interval [CI] = 5.0% to 5.4%) of ED presentations, 11.4% of ward admissions (1,956/17,184, 95% CI = 10.9% to 11.9%), and 19.9% of intensive care unit (ICU) admissions (104/523, 95% CI = 16.7% to 23.5%). The most common diagnoses were lower respiratory tract infection (20.2%), heart failure (14.9%), chronic obstructive pulmonary disease (13.6%), and asthma (12.7%). Hospital ward admission was required for 64% of patients (95% CI = 62% to 66%) with 3.3% (95% CI = 2.8% to 4.1%) requiring ICU admission. In-hospital mortality was 6% (95% CI = 5.0% to 7.2%).

CONCLUSION

Dyspnea is a common symptom in ED patients contributing substantially to ED, hospital, and ICU workload. It is also associated with significant mortality. There are a wide variety of causes however chronic disease accounts for a large proportion.

Role of computed tomography at a cancer center emergency department

To evaluate the imaging methods used at the emergency department (ED) of a cancer center, with emphasis on computed tomography (CT). A descriptive, retrospective, single-center study was conducted by reviewing imaging exams and medical records, after approval of the institution's Ethics Review Board. The demographic data, cancer history, and imaging exam requested were evaluated for all patients and the indications and results of head, chest, and abdominopelvic CT scans were also evaluated. During the study period, there were 8710 visits to the ED, and 5999 imaging studies were requested in 3788 patients (43.5 % of total of visits). One thousand eight hundred twenty-nine CT exams were used in 1121 visits (12.9 % of total of visits). The mean age of patients was 57.7 years and most patients (93.2 %) had a known primary tumor. The most common indications for abdominopelvic CT were non-oncologic emergencies (26.7 %) and postoperative complications (19.2 %), and the results were negative in 36.6 %, positive for clinical suspicion in 49.0 %, and incidental positive in 14.5 %. The most frequent indication for chest CT was suspected pulmonary embolism (34.4 %); however, only 11.1 % confirmed the diagnosis. The results of head TC were negative in 72.9 % and the indications that had more positive findings were suspected metastasis (32.1 %) and focal neurological sign/altered level of consciousness (24.5 %). CT plays an important role in driving the cancer patients visiting the ED. However, the high rate of negative or discordant results causes a concern for the inadvertent and excessive use of this imaging modality.

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.

Suboptimal implementation of diagnostic algorithms and overuse of computed tomography-pulmonary angiography in patients with suspected pulmonary embolism

BACKGROUND

Majority of our computed tomography-pulmonary angiography (CTPA) scans report negative findings. We hypothesized that suboptimal reliance on diagnostic algorithms contributes to apparent overuse of this test.

METHODS

A retrospective review was performed on 2031 CTPA cases in a large hospital system. Investigators retrospectively calculated pretest probability (PTP). Use of CTPA was considered as inappropriate when it was ordered for patients with low PTP without checking D-dimer (DD) or following negative DD.

RESULTS

Among the 2031 cases, pulmonary embolism (PE) was found in 7.4% (151 cases). About 1784 patients (88%) were considered "PE unlikely" based on Wells score. Out of those patients, 1084 cases (61%) did not have DD test prior to CTPA. In addition, 78 patients with negative DD underwent unnecessary CTPA; none of them had PE.

CONCLUSIONS

The suboptimal implementation of PTP assessment tools can result in the overuse of CTPA, contributing to ineffective utilization of hospital resources, increased cost, and potential harm to patients.