Emergency Evaluation for Pulmonary Embolism, Part 2: Diagnostic Approach

Optimizing emergency department imaging utilization for pulmonary emboli: A study on the effects of IV contrast rationing

PURPOSE

To study the impact of a contrast mitigation protocol on imaging utilization for pulmonary embolism (PE) in the emergency department (ED).

MATERIAL AND METHODS

Medical records of ED patients with suspected PE who underwent CT pulmonary angiography (CTPA) or ventilation-perfusion (VQ) scans were analyzed in control (3/15/22-4/15/22) and test (5/15/22-6/15/22) periods. The test period included a contrast mitigation protocol due to a global iodinated contrast shortage (05/2022-06/2022). Out of 610 scans, 28 were excluded for non-PE indications. Patient demographics, time metrics, and imaging reports were recorded.

RESULTS

Among 11,019 ED visits, there were 582 imaging events for suspected PE. The test period exhibited a significantly lower imaging rate of 4.16 % compared to 6.54 % in the control period (p < 0.001). CTPA usage decreased by 47.73 %, while VQ scan usage increased by 775.00 % during the test period. Test period positivity rate was 0.82 %, with CTPA at 0.58 % (1/173) and VQ scan at 1.43 % (1/70). In the control period, the positivity rate was 0.29 %, with CTPA at 0.30 % (1/331) and VQ scan at 0.00 % (0/8). Previous hospitalization history was significantly higher in the test period (70/243 vs. 39/339, p < 0.001). The positivity rates between the two periods showed no significant difference (p = 0.57). There were no significant differences in ED length of stay and image acquisition times.

CONCLUSION

The contrast mitigation protocol reduced CTPA use, increased VQ scans, and maintained positivity rates and image acquisition times. However, concerns persist about unnecessary imaging and low positivity rates, necessitating further research to optimize PE diagnostic algorithms.

Adherence to Best Practice Advice for Diagnosis of Pulmonary Embolism

PURPOSE

This study evaluated clinician adherence to the American College of Physicians Best Practice Advice for diagnosis of pulmonary embolism.

DESIGN

A prospective, single-center, descriptive design was utilized.

METHODS

A heterogeneous sample of 111 hemodynamically stable adult inpatients with a computed tomography pulmonary angiogram ordered was consented. Electronic medical records were reviewed for demographic and clinical variables to determine adherence. The 6 individual best practice statements and the overall adherence were evaluated by taking the sum of "yes" answers divided by the sample size.

RESULTS

Overall adherence was 0%. Partial adherence was observed with clinician-recorded clinical decisions rules and obtaining d-dimer (3.6% [4/111] and 10.2% [9/88], respectively) of low/intermediate probability scorers. Age adjustment of d-dimer was not recorded. Computed tomography pulmonary angiogram was the first diagnostic test in 89.7% (79/88) in low/intermediate probability patients.

CONCLUSION

In hemodynamically stable, hospitalized adults, adherence to best practice guidelines for diagnosis of pulmonary embolism was minimal. Clinical utility of the guidelines in hospitalized adults needs further evaluation. Systems problems (eg, lack of standardized orders, age-adjusted d-dimer values, information technology support) likely contributed to poor guideline adherence.

Serial use of existing clinical decisions aids can reduce computed tomography pulmonary angiography for pulmonary embolism

Pulmonary embolism (PE) remains a diagnostic challenge in emergency medicine. Clinical decision aids (CDAs) like the Pulmonary Embolism Rule-Out Criteria (PERC) are sensitive but poorly specific; serial CDA use may improve specificity. The goal of this before-and-after study was to determine if serial use of existing CDAs in a novel diagnostic algorithm safely decreases the use of CT pulmonary angiograms (CTPA). This was a retrospective before-and-after study conducted at an urban ED with 105,000 annual visits. Our algorithm uses PERC, Wells' score, and D-dimer in series, before moving to CTPA. The algorithm was introduced in January, 2017. Use of CDAs and D-dimer in the 24 months pre- and 12 months post-intervention were obtained by chart review. The algorithm's effect on CTPA ordering was assessed by comparing volume 5 years pre- and 3 years post-intervention, adjusted for ED volume. Mean CTPAs per 1000 adult ED visits was 11.1 in the 5 pre-intervention years and 9.9 in the 3 post-intervention years (p < 0.0001). Use of PERC, Wells' score and D-dimer increased from 1.1%, 1.1%, and 28% to 8.8% (p = 0.0002) 8.1% (p = 0.0005), and 35% (p = 0.0066), respectively. Pre-intervention, there were six potentially missed PEs compared to three in the post-intervention period. Introduction of our serial CDA diagnostic algorithm was associated with increased use of CDAs and D-dimer and reduced CTPA rate without an apparent increase in the number of missed PEs. Prospective validation is needed to confirm these results.

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.

D-dimer can help differentiate suspected pulmonary embolism patients that require anti-coagulation

Objectives

Determine whether D-dimer concentration in the absence of imaging can differentiate patients that require anti-coagulation from patients who do not require anti-coagulation.

Methods

Data was obtained retrospectively from 366 hemodynamically stable adult ED patients with suspected pulmonary embolism (PE).

Patients were categorized by largest occluded artery and aggregated into: ‘Require anti-coagulation’ (main, lobar, and segmental PE), ‘Does not require anti-coagulation’ (sub-segmental and No PE), ‘High risk of deterioration’ (main and lobar PE), and ‘Not high risk of deterioration’ (segmental, sub-segmental, and No PE) groups.

Wilcoxon rank-sum test was used for 2 sample comparisons of median D-dimer concentrations. Receiver operating characteristic (ROC) curve analysis was utilized to determine a D-dimer cut-off that could differentiate ‘Require anti-coagulation’ from ‘Does not require anti-coagulation’ and ‘High risk of deterioration’ from ‘Low risk of deterioration’ groups.

Results

The ‘Require anti-coagulation’ group had a maximum area under the curve (AUC) of 0.92 at an age-adjusted D-dimer cut-off of 1540 with a specificity of 86% (95% CI, 81–91%), and sensitivity of 84% (79–90%). The ‘High risk of deterioration’ group had a maximum AUC of 0.93 at an age-adjusted D-dimer cut-off of 2500 with a specificity of 90% (85–93%) and sensitivity of 83% (77–90%).

Conclusions

An age-adjusted D-dimer cut-off of 1540 ng/mL differentiates suspected PE patients requiring anti-coagulation from those not requiring anti-coagulation. A cut-off of 2500 differentiates those with high risk of clinical deterioration from those not at high risk of deterioration. When correlated with clinical outcomes, these cut-offs can provide an objective method for clinical decision making when imaging is unavailable.

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ED providers are faced with risks and benefits when empirically administering anti-coagulation for suspected PE patients.

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We show that D-dimer concentration can be used as a clinical decision making tool to minimize these risks.

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A D-dimer cut-off of 1540 ng/mL can be used to minimize unnecessary anti-coagulation exposure in patients who do not need it.

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Using a 2500 ng/mL D-dimer cut-off minimizes the risk of withholding treatment for those at risk of clinical deterioration.

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Both cut-offs along with clinical gestalt are an objective measure weighing the risks & benefits of empiric anti-coagulation.

Cardiovascular Considerations in Caring for Pregnant Patients: A Scientific Statement From the American Heart Association

Cardio-obstetrics has emerged as an important multidisciplinary field that requires a team approach to the management of cardiovascular disease during pregnancy. Cardiac conditions during pregnancy include hypertensive disorders, hypercholesterolemia, myocardial infarction, cardiomyopathies, arrhythmias, valvular disease, thromboembolic disease, aortic disease, and cerebrovascular diseases. Cardiovascular disease is the primary cause of pregnancy-related mortality in the United States. Advancing maternal age and preexisting comorbid conditions have contributed to the increased rates of maternal mortality. Preconception counseling by the multidisciplinary cardio-obstetrics team is essential for women with preexistent cardiac conditions or history of preeclampsia. Early involvement of the cardio-obstetrics team is critical to prevent maternal morbidity and mortality during the length of the pregnancy and 1 year postpartum. A general understanding of cardiovascular disease during pregnancy should be a core knowledge area for all cardiovascular and primary care clinicians. This scientific statement provides an overview of the diagnosis and management of cardiovascular disease during pregnancy.

Concise Review of the Clinical Approach to the Exclusion and Diagnosis of Pulmonary Embolism in 2020

Pulmonary embolism has extremely varied clinical presentations and can be difficult to diagnose. Clinical decision rules can help determine the probability of pulmonary embolism by assessment of the clinical presentation. After the diagnosis, several prognostic rules can be used to risk-stratify and facilitate outpatient treatment of pulmonary embolism. This review addresses the utility of clinical decision rules, biomarkers in the diagnosis of pulmonary emoblism, high-risk patient phenotypes, the use of this data to make disposition decisions for patients with a diagnosis of PE, and recent shifts in the management of pulmonary embolism in the clinical setting.

Comparison and screening of different risk assessment models for deep vein thrombosis in patients with solid tumors

To increase the detection rate of deep vein thrombosis (DVT) and to compare the predictive value of four different risk assessment scales (Caprini, Autar, Pauda, and Khorana scales) for DVT in patients with solid tumors by the receiver operating curve (ROC). A total of 361 patients with all kinds of malignant solid tumors, who accepted anti-tumor therapy in the cancer center between March 3, 2015 to April 13, 2018, were assigned to a group of 230 cases diagnosed with DVT and a control group of 131 cases without DVT. Data were recorded and summarized, and the predictive value of the above four risk assessment scales for DVT in solid tumor patients was compared based on the area under the ROC curve (AUC). The AUC values determined for the Caprini, Autar, Pauda, and Khorana scales were (0.631 ± 0.030), (0.686 ± 0.028), (0.654 ± 0.029), and (0.599 ± 0.032), respectively; maximum sensitivity, specificity, and Youden index were 80.9% for Khorana, 86.3% for Caprini, and 29.6% for Autar scale, respectively. We found no statistically significant differences in the AUC values between Autar and Caprini, Autar and Khorana, as well as Khorana and Pauda (p > 0.05). However, the AUC differences between Autar and Pauda, Caprini and Khorana, as well as Caprini and Pauda were statistically significant (p < 0.05). All four risk assessment models showed some value in the risk prediction of DVT in patients with solid tumors, but every model also exhibited its own restrictions; maximum sensitivity, specificity, and Youden index were 80.9% for Khorana, 86.3% for Caprini, and 29.6% for Autar scale, respectively. We confirmed that the detection rate can be improved by modifying the BMI cut-off value of the scale or by combining appropriate scales.

Maternal cardiac arrest

PURPOSE OF REVIEW

The review is intended to serve as a practical clinical aid for the clinician called to maternal cardiac arrest.

RECENT FINDINGS

Anesthesia complications comprise an important cause of maternal cardiac arrest in developed countries Also predominant are hemorrhage and infections. Recent in-depth reports highlight fractionated care for pregnant women with cardiac and also probably neurological comorbidities. Pathology reports reveal a prevalence of thromboembolic phenomena that is higher than previously assumed but still rare. These are accompanied by particularly high mortality rates. The presenting rhythms of cardiac arrest which differ from most cardiac arrest populations, suggest the need for further in-depth investigation of both the causes and management of these cases. Despite these, outcomes are far better than those of most arrests. Key differences in treatment include are consideration of early airway management and possible medication complications. Pulseless electrical activity and VF should always alert to the possibility of hemorrhage. Echocardiography can diagnose thromboembolism. Also different are the need for Left uterine displacement and early delivery within after 4-5 min of initiation of resuscitation effort in cases with suspected compromise of the venous return or a poor likelihood of a good maternal outcome.

SUMMARY

Maternal cardiac arrest should be managed similarly to other adult cardiac arrests. At the same time its unique reversible causes require a different form of thought regarding diagnosis and treatment during the code.

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.

Multicenter Evaluation of the YEARS Criteria in Emergency Department Patients Evaluated for Pulmonary Embolism

BACKGROUND

It may be possible to safely rule out pulmonary embolism (PE) in patients with low pretest probability (PTP) using a higher than standard D-dimer threshold. The YEARS criteria, which include three questions from the Wells PE score to identify low-PTP patients and a variable D-dimer threshold, was recently shown to decrease the need for imaging to rule out PE by 14% in a multicenter study in the Netherlands. However, the YEARS approach has not been studied in the United States.

METHODS

This study was a prospective, observational study of consecutive adult patients evaluated for PE in 17 U.S. emergency departments. Prior to diagnostic testing, we collected the YEARS criteria: "Does the patient have clinical signs or symptoms of DVT?" "Does the patient have hemoptysis?" "Are alternative diagnoses less likely than PE?" with YEARS (+) being any "yes" response. A negative D-dimer was <1000 mg/dL for YEARS (-) patients and <500 mg/dL for YEARS (+) patients. We calculated test characteristics and used Fisher's exact test to compare proportions of patients who would have been referred for imaging and patients who would have had PE "missed."

RESULTS

Of 1,789 patients, 84 (4%) had PE, 1,134 (63%) were female, 1,038 (58%) were white, and mean (±SD) age was 48 (±16) years. Using the standard D-dimer threshold, 940 (53%) would not have had imaging, with two (0.2%, 95% confidence interval [CI] = 0.02%-0.60%) missed PE. Using YEARS adjustment, 1,204 (67%, 95% CI = 65%-69%) would not have been referred for imaging, with six (0.5%, 95% CI = 0.18%-1.1%) missed PE, and using "alternative diagnoses less likely than PE" adjustment, 1,237 (69%, 95% CI = 67%-71%) would not have had imaging with six (0.49%, 95% CI = 0.18%-1.05%) missed PE. Sensitivity was 97.6% (95% CI = 91.7%-99.7%) for the standard threshold and 92.9% (95% CI = 85%-97%) for both adjusted thresholds. Negative predictive value (NPV) was nearly 100% for all approaches.

CONCLUSIONS

D-dimer adjustment based on PTP may result in a reduced need for imaging to evaluate possible PE, with some additional missed PE but no decrease in NPV.

Best Clinical Practice: Controversies in Outpatient Management of Acute Pulmonary Embolism

BACKGROUND

Pulmonary embolism (PE) is a common condition managed in the emergency department (ED), with a wide range of morbidity and mortality. Patients are classically admitted for treatment and monitoring of anticoagulation.

OBJECTIVE

We sought to evaluate the controversy concerning outpatient therapy for patients with acute PE and investigate the feasibility, safety, and efficacy of outpatient management.

DISCUSSION

Patients with venous thromboembolism have historically been admitted for treatment and monitoring for concern of worsening disease or side effects of anticoagulation (bleeding). More than 90% of EDs admit patients with PE in the United States. However, close to 50% of patients may be appropriate for discharge and outpatient therapy. The published literature suggests that outpatient treatment is safe, feasible, and efficacious, with similar rates of recurrent venous thromboembolism and all-cause mortality, especially with novel oral anticoagulants. Multiple scoring criteria can be used, including the Pulmonary Embolism Severity Index (PESI), simplified PESI, Hestia criteria, Geneva Prognostic Score, European Society of Cardiology guidelines, Global Registry of Acute Coronary Events, and Aujesky score. Simplified PESI and the European Society of Cardiology guidelines have high-quality evidence, sufficient sensitivity, and ease of use for the ED. Patients considered for outpatient therapy should possess low hemorrhage risk, adequate social situation, negative biomarkers, ability to comply, and no alternate need for admission.

CONCLUSIONS

Patients with acute PE are often admitted in the United States, but a significant proportion may be appropriate for discharge. Patients with low risk for adverse events according to clinical scoring criteria, adequate follow-up, ability to comply, and no other need for admission can be discharged with novel oral anticoagulant therapy.

Differential effect of mild and severe pulmonary embolism on the rat lung transcriptome

BACKGROUND

Pulmonary thromboembolism (PTE) is a common diagnosis and a leading cause of cardiovascular morbidity and mortality. A growing literature has associated PE with systemic inflammation, and global hyper-coagulability, which contribute to lung remodeling and clot recurrence. The source and mechanism of inflammation remains unstudied. In humans, inhibition of cholesterol synthesis with statins decreases biomarkers of inflammation. We test the differential effect of pulmonary vascular occlusion during mild and severe pulmonary embolism on the lung transcriptome.

METHODS

Experimental PE was induced in adult male rats by injection of 25 micron polystyrene microspheres into the jugular vein. The effect of Mild PE, (2-h right ventricular systolic pressure [RVSP] normal, 18-h RVSP 44 mmHg) and Severe PE (2-h RVSP > 50 mmHg; 18-h RVSP 44 mmHg) on lungs was assessed by measuring transcriptome-wide changes in gene expression by DNA microarrays.

RESULTS

Severe PE was associated with a large change in lung gene expression and in the expression of KEGG pathways and other gene functional annotation groups. Mild PE was also associated with a large number of significant changes in gene expression and in the expression of KEGG pathways and gene functional annotation groups, even after only 2 h of PE. Up-regulated pathways included increased adipocytokine, chemokine and cytokine signaling as well as cholesterol synthesis.

CONCLUSIONS

Mild PE without acute pulmonary hypertension (PH) increased lung gene expression of inflammatory pathways, including increased cholesterol synthesis. These data indicate that even mild persistent pulmonary vascular occlusion is capable of inciting an inflammatory response from the lung. These data imply the detrimental effect of unresolved pulmonary obstruction from PE.