Diagnostic prediction models for suspected pulmonary embolism: systematic review and independent external validation in primary care

Comparisons of clinical scoring systems among suspected pulmonary embolism patients presenting to emergency department

Introduction

Pulmonary embolism (PE) is among the most severe cardiovascular disorders worldwide. Timely and appropriate diagnosis of PE remains an important step in reducing PE related mortality and morbidity.

Methods

In this retrospective single-center cohort study, we comprehensively compared the screening performances of several clinical scoring systems (Wells score [WS], Revised Geneva score [RGS], WS + d-Dimer [D-D], RGS + D-D, WS + PE rule-out criteria [PERC] and RGS + PERC) among PE suspected patients. Failure rates across different PE severity grades as well as overall sensitivity/specificity were considered in evaluating each screening strategy.

Results

A total of 3437 patients were included in this study and 698 of them were diagnosed with PE. Patients with and without PE were similar in demographics, while significantly different in respiration-related characteristics. Compared with WS or RGS alone, Integrating PERC or D-D with WS or RGS significantly decreased the failure rates across all PE severity grades, and increased the overall sensitivity from 88.5% and 87.2% to 96.3% and 94.8% (D-D) to 99.4% and 99.6% (PERC), respectively. However, compared with other four scoring approaches, using WS or RGS alone increased the specificity from 8.3% and 7.2%, 38.3% and 21.3%, to 63.5% and 34.8%, respectively, and increased the AUC from 0.54 to 0.54, 0.70 and 0.69, to 0.8 and 0.76, respectively. In general, all screening approaches achieved better performances among PE patients with respiratory distress compared to those without respiratory distress.

Conclusion

Combining PERC or D-D with WS or RGS, and the presence of respiratory distress provide significantly better PE rule-out performances.

Machine Learning-Based Predictive Models for Patients with Venous Thromboembolism: A Systematic Review

BACKGROUND

 Venous thromboembolism (VTE) is a chronic disorder with a significant health and economic burden. Several VTE-specific clinical prediction models (CPMs) have been used to assist physicians in decision-making but have several limitations. This systematic review explores if machine learning (ML) can enhance CPMs by analyzing extensive patient data derived from electronic health records. We aimed to explore ML-CPMs' applications in VTE for risk stratification, outcome prediction, diagnosis, and treatment.

METHODS

 Three databases were searched: PubMed, Google Scholar, and IEEE electronic library. Inclusion criteria focused on studies using structured data, excluding non-English publications, studies on non-humans, and certain data types such as natural language processing and image processing. Studies involving pregnant women, cancer patients, and children were also excluded. After excluding irrelevant studies, a total of 77 studies were included.

RESULTS

 Most studies report that ML-CPMs outperformed traditional CPMs in terms of receiver operating area under the curve in the four clinical domains that were explored. However, the majority of the studies were retrospective, monocentric, and lacked detailed model architecture description and external validation, which are essential for quality audit. This review identified research gaps and highlighted challenges related to standardized reporting, reproducibility, and model comparison.

CONCLUSION

 ML-CPMs show promise in improving risk assessment and individualized treatment recommendations in VTE. Apparently, there is an urgent need for standardized reporting and methodology for ML models, external validation, prospective and real-world data studies, as well as interventional studies to evaluate the impact of artificial intelligence in VTE.

Venous Thrombosis in Acute Pancreatitis: What to and Not to Do?

Acute pancreatitis is an acute inflammatory condition of the pancreas that has not only local but systemic effects as well. Venous thrombosis is one such complication which can give rise to thrombosis of the peripheral vasculature in the form of deep vein thrombosis, pulmonary embolism, and splanchnic vein thrombosis. The prevalence of these complications increases with the severity of the disease and adds to the adverse outcomes profile. With better imaging and awareness, more cases are being detected, although many at times it can be an incidental finding. However, it remains understudied and strangely, most of the guidelines on the management of acute pancreatitis are silent on this aspect. This review offers an overview of the incidence, pathophysiology, symptomatology, diagnostic work-up, and management of venous thrombosis that develops in AP.

Development and validation of a novel model to predict pulmonary embolism in cardiology suspected patients: A 10-year retrospective analysis

As there are no predictive models for pulmonary embolism (PE) in patients with suspected PE at cardiology department. This study developed a predictive model for the probability of PE development in these patients. This retrospective analysis evaluated data from 995 patients with suspected PE at the cardiology department from January 2012 to December 2021. Patients were randomly divided into the training and validation cohorts (7:3 ratio). Using least absolute shrinkage and selection operator regression, optimal predictive features were selected, and the model was established using multivariate logistic regression. The features used in the final model included clinical and laboratory factors. A nomogram was developed, and its performance was assessed and validated by discrimination, calibration, and clinical utility. Our predictive model showed that six PE-associated variables (age, pulse, systolic pressure, syncope, D-dimer, and coronary heart disease). The area under the curve - receiver operating characteristic curves of the model were 0.721 and 0.709 (95% confidence interval: 0.676-0.766 and 0.633-0.784), respectively, in both cohorts. We also found good consistency between the predictions and real observations in both cohorts. In decision curve analysis, the numerical model had a good net clinical benefit. This novel model can predict the probability of PE development in patients with suspected PE at cardiology department.

D-dimer levels to exclude pulmonary embolism and reduce the need for CT angiography in COVID-19 in an outpatient population

OBJECTIVES

Emerging results indicate that, in COVID-19, thromboembolic complications contribute to the high mortality and morbidity. Previous research showed that the prevalence of pulmonary embolism (PE) is between 25-50% in COVID-19 patients, however, most of these reports are based on data from patients with severe pneumonia, treated in intensive care units.

MATERIALS AND METHODS

We conducted a retrospective, single-center, observational study to estimate the prevalence of PE in COVID-19 patients who underwent CT angiography and to identify the most important predictors. Adult outpatients with COVID-19, who presented at our COVID Outpatient Clinic between 1st and 31st of March in 2021 and underwent CTA examination were included in this study. Multiple linear regression analysis was used to identify predictors of PE in COVID-19 patients. The predictors were: age, gender, disease duration, CT severity index and log-transformed quantitative D-dimer (logQDDIM) value.

RESULTS

843 COVID-19 patients were included into the study. 82.56% (693 patients) of the infected patients had a pulmonary CTA examination and D-dimer levels (mean age: 59.82 years ± 15.66). 7.61% (53 patients) of the patients had PE. 2.02% (14 patients) of the patients had main branch or lobar PE. The multiple regression analysis found that only logQDDIM was a significant predictor. A logQDDIM cut-off value of 0.0169 (1.0171 ug/ml serum D-dimer) predicted PE with 99% sensitivity (p<0.0001, degree-of-freedom = 570, AUC = 0.72).

CONCLUSIONS

We demonstrated in a large cohort of COVID-19 patients that a cut-off value of QDDIM of 1ug/ml can exclude pulmonary embolism in an outpatient setting, implicating that QDDIM might potentially supersede CTA as a screening approach in COVID-19 outpatient clinics.

Risk Scores in Venous Thromboembolism Guidelines of ESC, ACCP, and ASH: An Updated Review

Venous thromboembolism (VTE) is associated with high morbidity and mortality. Risk scores associated with VTE have been widely used in clinical practice. Among numerous scores published, those included in guidelines are usually typical risk scores which have been extensively validated and globally recognized. This review provides an updated overview of the risk scores associated with VTE endorsed by 3 guidelines which are highly recognized in the field of VTE including the European Society of Cardiology, American College of Chest Physicians, and American Society of Hematology, focusing on the development, modification, validation, and comparison of these scores, to provide a comprehensive and updated understanding of all the classic risk scores associated with VTE to medical readers including but not limited to cardiologists, pulmonologists, hematologists, intensivists, physicians, surgeons, and researchers. Although each score recommended by these guidelines was more or less validated, there may still be room for further improvement. It may still be necessary to seek simpler, more practical, and more universally applicable VTE-related risk scores in the future.

[Recommendations for thromboembolic disease in oncological processes. A view from primary care]

Venous thromboembolic disease (VTE) is a frequent complication in patients diagnosed with cancer and a cause of morbidity and mortality. Approximately 20% of thromboembolic episodes develop in association with active cancer. On the other hand, it is estimated that about 2-12% of cases, the thromboembolic episode is the first manifestation of an occult cancer, diagnosed at that time or subsequently, which offers an opportunity for early diagnosis and treatment. There are multiple factors that contribute to increase the risk of VTE in oncological patients in relation to specific characteristics of the patient, the tumor and the treatments. Knowledge of these risk factors will contribute to early diagnosis when signs of VTE appear, as well as the assessment of thromboprophylaxis if indicated. The diagnosis of VTE in patients with cancer does not differ of those who do not suffer from it. Regarding the treatment of VTE in these patients, low molecular weight heparin (LMWH), direct acting anticoagulants (DACs) and antivitamin K (VKA) are the most commonly used, although the dosing regimen and length are not clear yet. The management of these patients should be interdisciplinary and early, so the primary care physician plays a key role in this process as he/she is liaise with his/her patients. It is also necessary to update knowledge in order to improve the care of these patients. For these reasons, this document has been prepared by the Working Group on Vasculopathies of the Spanish Society of Primary Care Physicians (SEMERGEN) whose objective is to present the available information regarding the management of VTE that may appear in oncological patients, as well as the assessment of thromboprophylaxis and treatment, if appropriate, from an approach focused on a primary care field.

Excluding pregnancy-associated deep vein thrombosis with whole-leg ultrasound

Background

Deep vein thrombosis (DVT) is common in pregnancy, yet data are limited on the best diagnostic strategies in pregnant patients suspected of DVT.

Objectives

We conducted a prospective cohort study to evaluate the rate of symptomatic DVT in the 90 days after a negative whole-leg compression ultrasound (CUS) in pregnant women presenting with DVT symptoms.

Methods

In this prospective cohort study, we enrolled pregnant patients suspected of DVT between 2011 and 2019 who were referred to the vascular imaging laboratory at a tertiary care center and had anticoagulation held after a negative whole-leg CUS. Primary outcome was objectively confirmed DVT or pulmonary embolism or death due to venous thromboembolism (VTE).

Results

Whole-leg CUS yielded normal results in 186 patients (97.9%) and identified DVT in 4 (2.1%). The mean age was 30 and 164 were White. Among the 186 patients with a negative, initial whole-leg CUS who did not receive anticoagulation, there were 2 DVT events identified over the 90-day follow-up period, for an overall rate of 1.1% (95% CI: 0.2-3.4%). The study was terminated before full planned accrual for administrative reasons.

Conclusion

The rate of symptomatic DVT is low in pregnant patients who have a single, negative whole-leg CUS and did not receive anticoagulation. Adequately powered studies should prospectively assess whole-leg CUS in a larger population alone and in combination with pre-test probability scores and/or D-dimer to determine its role in the evaluation of suspected DVT in pregnancy.

American Society of Hematology, ABHH, ACHO, Grupo CAHT, Grupo CLAHT, SAH, SBHH, SHU, SOCHIHEM, SOMETH, Sociedad Panamena de Hematología, Sociedad Peruana de Hematología, and SVH 2023 guidelines for diagnosis of venous thromboembolism and for its management in special populations in Latin America

Implementation of international guidelines in Latin American settings requires additional considerations (ie, values and preferences, resources, accessibility, feasibility, and impact on health equity). The purpose of this guideline is to provide evidence-based recommendations about the diagnosis of venous thromboembolism (VTE) and its management in children and during pregnancy. We used the GRADE ADOLOPMENT method to adapt recommendations from 3 American Society of Hematology (ASH) VTE guidelines (diagnosis of VTE, VTE in pregnancy, and VTE in the pediatric population). ASH and 12 local hematology societies formed a guideline panel comprising medical professionals from 10 countries in Latin America. Panelists prioritized 10 questions about the diagnosis of VTE and 18 questions about its management in special populations that were relevant for the Latin American context. A knowledge synthesis team updated evidence reviews of health effects conducted for the original ASH guidelines and summarized information about factors specific to the Latin American context. In comparison with the original guideline, there were significant changes in 2 of 10 diagnostic recommendations (changes in the diagnostic algorithms) and in 9 of 18 management recommendations (4 changed direction and 5 changed strength). This guideline ADOLOPMENT project highlighted the importance of contextualizing recommendations in other settings based on differences in values, resources, feasibility, and health equity impact.

Comparison of VTE risk scores in guidelines for VTE diagnosis in nonsurgical hospitalized patients with suspected VTE

BACKGROUND

The assessment of VTE likelihood with VTE risk scores is essential prior to imaging examinations during VTE diagnostic procedure. Little is known with respect to the disparity of predictive power for VTE diagnosis among VTE risk scores in guidelines for nonsurgical hospitalized patients with clinically suspected VTE.

METHODS

A retrospective study was performed to compare the predictive power for VTE diagnosis among the Wells, Geneva, YEARS, PERC, Padua, and IMPROVE scores in the leading authoritative guidelines in nonsurgical hospitalized patients with suspected VTE.

RESULTS

Among 3168 nonsurgical hospitalized patients with suspected VTE, VTE was finally excluded in 2733(86.3%) ones, whereas confirmed in 435(13.7%) ones. The sensitivity and specificity resulted from the Wells, Geneva, YEARS, PERC, Padua, and IMPROVE scores were (90.3%, 49.8%), (88.7%, 53.6%), (73.8%, 50.2%), (97.7%,16.9%), (80.9%, 44.0%), and (78.2%, 47.0%), respectively. The YI were 0.401, 0.423, 0.240, 0.146, 0.249, and 0.252 for the Wells, Geneva, YEARS, PERC, Padua, and IMPROVE scores, respectively. The C-index were 0.694(0.626-0.762), 0.697(0.623-0.772), 0.602(0.535-0.669), 0.569(0.486-0.652), 0.607(0.533-0.681), and 0.609(0.538-0.680) for the Wells, Geneva, YEARS, PERC, Padua, and IMPROVE scores, respectively. Consistency was significant in the pairwise comparison of Wells vs Geneva(Kappa 0.753, P = 0.565), YEARS vs Padua(Kappa 0.816, P = 0.565), YEARS vs IMPROVE(Kappa 0.771, P = 0.645), and Padua vs IMPROVE(Kappa 0.789, P = 0.812), whereas it did not present in the other pairs. The YI was improved to 0.304, 0.272, and 0.264 for the PERC(AUC 0.631[0.547-0.714], P = 0.006), Padua(AUC 0.613[0.527-0.700], P = 0.017), and IMPROVE(AUC 0.614[0.530-0.698], P = 0.016), with a revised cutoff of 5 or less, 6 or more, and 4 or more denoting the VTE-likely, respectively.

CONCLUSIONS

For nonsurgical hospitalized patients with suspected VTE, the Geneva and Wells scores perform best, the PERC scores performs worst despite its significantly high sensitivity, whereas the others perform intermediately, albeit the absolute predictive power of all isolated scores are mediocre. The predictive power of the PERC, Padua, and IMPROVE scores are improved with revised cutoffs.

Pulmonary embolism in patients with COVID-19 and D-dimer diagnostic value: A retrospective study

BACKGROUND

D-dimer levels are significantly higher in COVID-19 patients with Pulmonary Thromboembolism (PTE) as compared to those without PTE, but its clinical utility is still uncertain.

PURPOSE

To determine the D-dimer performance for ruling out PTE in patients with COVID-19. We also assessed clinical and laboratory factors associated with the presence of PTE on CT Pulmonary Angiogram (CTPA).

METHODS

Retrospective study involving all patients who presented at a tertiary care hospital from March 2020 to May 2021 with severe acute respiratory syndrome from COVID-19, who underwent CTPA and had D-dimer collected within 48 hours from CTPA. The D-dimer ability to classify patients with or without PTE according to CTPA was evaluated.

RESULTS

A total of 697 patients [382 (54.8%) men; mean (SD) age, 59 (20.5) years] were included, of which 71.5% required intensive care admission, 32.4% had PTE, and 35.6% died during hospitalization. PTE was independently associated with mortality [42.5% vs. 32.3%; p = 0.038]. D-dimer levels were higher in patients with PTE [9.1 (3.9; 20) vs. 2.3 (1.2; 5.1); p < 0.001]. Using the D-dimer cutoff of 0.5 μg/mL or above, sensitivity was 98.2% and specificity 5.7%. The 0.3 μg/mL threshold was associated with 100% of sensitivity for the presence of PTE, with which 99.1% of patients had increased values. ROC curve AUC was 0.77, demonstrating moderate discriminative power of D-dimers to detect PTE.

CONCLUSIONS

D-dimer levels are higher among COVID-19 hospitalized patients with PTE as compared to those without PTE and have moderate discriminative power to detect PTE, but its use to exclude PTE in this population may have limited clinical utility.

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

BACKGROUND

The challenging clinical dilemma of detecting pulmonary embolism (PE) in suspected patients is encountered in a variety of healthcare settings. We hypothesized that the optimal diagnostic approach to detect these patients in terms of safety and efficiency depends on underlying PE prevalence, case mix, and physician experience, overall reflected by the type of setting where patients are initially assessed. The objective of this study was to assess the capability of ruling out PE by available diagnostic strategies across all possible settings.

METHODS AND FINDINGS

We performed a literature search (MEDLINE) followed by an individual patient data (IPD) meta-analysis (MA; 23 studies), including patients from self-referral emergency care (n = 12,612), primary healthcare clinics (n = 3,174), referred secondary care (n = 17,052), and hospitalized or nursing home patients (n = 2,410). Multilevel logistic regression was performed to evaluate diagnostic performance of the Wells and revised Geneva rules, both using fixed and adapted D-dimer thresholds to age or pretest probability (PTP), for the YEARS algorithm and for the Pulmonary Embolism Rule-out Criteria (PERC). All strategies were tested separately in each healthcare setting. Following studies done in this field, the primary diagnostic metrices estimated from the models were the "failure rate" of each strategy-i.e., the proportion of missed PE among patients categorized as "PE excluded" and "efficiency"-defined as the proportion of patients categorized as "PE excluded" among all patients. In self-referral emergency care, the PERC algorithm excludes PE in 21% of suspected patients at a failure rate of 1.12% (95% confidence interval [CI] 0.74 to 1.70), whereas this increases to 6.01% (4.09 to 8.75) in referred patients to secondary care at an efficiency of 10%. In patients from primary healthcare and those referred to secondary care, strategies adjusting D-dimer to PTP are the most efficient (range: 43% to 62%) at a failure rate ranging between 0.25% and 3.06%, with higher failure rates observed in patients referred to secondary care. For this latter setting, strategies adjusting D-dimer to age are associated with a lower failure rate ranging between 0.65% and 0.81%, yet are also less efficient (range: 33% and 35%). For all strategies, failure rates are highest in hospitalized or nursing home patients, ranging between 1.68% and 5.13%, at an efficiency ranging between 15% and 30%. The main limitation of the primary analyses was that the diagnostic performance of each strategy was compared in different sets of studies since the availability of items used in each diagnostic strategy differed across included studies; however, sensitivity analyses suggested that the findings were robust.

CONCLUSIONS

The capability of safely and efficiently ruling out PE of available diagnostic strategies differs for different healthcare settings. The findings of this IPD MA help in determining the optimum diagnostic strategies for ruling out PE per healthcare setting, balancing the trade-off between failure rate and efficiency of each strategy.

Development of a risk score to guide targeted hepatitis C testing among human immunodeficiency virus patients in Cambodia

BACKGROUND

The World Health Organization recommends testing all human immunodeficiency virus (HIV) patients for hepatitis C virus (HCV). In resource-constrained contexts with low-to-intermediate HCV prevalence among HIV patients, as in Cambodia, targeted testing is, in the short-term, potentially more feasible and cost-effective.

AIM

To develop a clinical prediction score (CPS) to risk-stratify HIV patients for HCV coinfection (HCV RNA detected), and derive a decision rule to guide prioritization of HCV testing in settings where ‘testing all’ is not feasible or unaffordable in the short term.

METHODS

We used data of a cross-sectional HCV diagnostic study in the HIV cohort of Sihanouk Hospital Center of Hope in Phnom Penh. Key populations were very rare in this cohort. Score development relied on the Spiegelhalter and Knill-Jones method. Predictors with an adjusted likelihood ratio ≥ 1.5 or ≤ 0.67 were retained, transformed to natural logarithms, and rounded to integers as score items. CPS performance was evaluated by the area-under-the-ROC curve (AUROC) with 95% confidence intervals (CI), and diagnostic accuracy at the different cut-offs. For the decision rule, HCV coinfection probability ≥1% was agreed as test-threshold.

RESULTS

Among the 3045 enrolled HIV patients, 106 had an HCV coinfection. Of the 11 candidate predictors (from history-taking, laboratory testing), seven had an adjusted likelihood ratio ≥ 1.5 or ≤ 0.67: ≥ 50 years (+1 point), diabetes mellitus (+1), partner/household member with liver disease (+1), generalized pruritus (+1), platelets < 200 × 10⁹/L (+1), aspartate transaminase (AST) < 30 IU/L (-1), AST-to-platelet ratio index (APRI) ≥ 0.45 (+1), and APRI < 0.45 (-1). The AUROC was 0.84 (95%CI: 0.80-0.89), indicating good discrimination of HCV/HIV coinfection and HIV mono-infection. The CPS result ≥0 best fits the test-threshold (negative predictive value: 99.2%, 95%CI: 98.8-99.6). Applying this threshold, 30% (n = 926) would be tested. Sixteen coinfections (15%) would have been missed, none with advanced fibrosis.

CONCLUSION

The CPS performed well in the derivation cohort, and bears potential for other contexts of low-to-intermediate prevalence and little onward risk of transmission(i.e. cohorts without major risk factors as injecting drug use, men having sex with men), and where available resources do not allow to test all HIV patients as recommended by WHO. However, the score requires external validation in other patient cohorts before any wider use can be considered.

Construction of a Risk Prediction Model for Hospital-Acquired Pulmonary Embolism in Hospitalized Patients

The purpose of this study is to establish a novel pulmonary embolism (PE) risk prediction model based on machine learning (ML) methods and to evaluate the predictive performance of the model and the contribution of variables to the predictive performance. We conducted a retrospective study at the Shanghai Tenth People's Hospital and collected the clinical data of in-patients that received pulmonary computed tomography imaging between January 1, 2014 and December 31, 2018. We trained several ML models, including logistic regression (LR), support vector machine (SVM), random forest (RF), and gradient boosting decision tree (GBDT), compared the models with representative baseline algorithms, and investigated their predictability and feature interpretation. A total of 3619 patients were included in the study. We discovered that the GBDT model demonstrated the best prediction with an area under the curve value of 0.799, whereas those of the RF, LR, and SVM models were 0.791, 0.716, and 0.743, respectively. The sensibilities of the GBDT, LR, RF, and SVM models were 63.9%, 68.1%, 71.5%, and 75%, respectively; the specificities were 81.1%, 66.1, 72.7%, and 65.1%, respectively; and the accuracies were 77.8%, 66.5%, 72.5%, and 67%, respectively. We discovered that the maximum D-dimer level contributed the most to the outcome prediction, followed by the extreme growth rate of the plasma fibrinogen level, in-hospital duration, and extreme growth rate of the D-dimer level. The study demonstrates the superiority of the GBDT model in predicting the risk of PE in hospitalized patients. However, in order to be applied in clinical practice and provide support for clinical decision-making, the predictive performance of the model needs to be prospectively verified.

Dementia risk in the general population: large-scale external validation of prediction models in the AGES-Reykjavik study

We aimed to evaluate the external performance of prediction models for all-cause dementia or AD in the general population, which can aid selection of high-risk individuals for clinical trials and prevention. We identified 17 out of 36 eligible published prognostic models for external validation in the population-based AGES-Reykjavik Study. Predictive performance was assessed with c statistics and calibration plots. All five models with a c statistic > .75 (.76-.81) contained cognitive testing as a predictor, while all models with lower c statistics (.67-.75) did not. Calibration ranged from good to poor across all models, including systematic risk overestimation or overestimation for particularly the highest risk group. Models that overestimate risk may be acceptable for exclusion purposes, but lack the ability to accurately identify individuals at higher dementia risk. Both updating existing models or developing new models aimed at identifying high-risk individuals, as well as more external validation studies of dementia prediction models are warranted.

Comprehensive management of acute pulmonary embolism in primary care using telemedicine in the COVID-era

A healthy, active woman in her 70s reported intermittent exertional dyspnoea for 2 months, notable during frequent open-water swimming. Symptoms were similar to an episode of travel-provoked pulmonary embolism 3 years prior. She denied chest pain, cough, fever, extremity complaints and symptoms at rest. Due to the COVID-19 pandemic, her healthcare system was using secure telemedicine to evaluate non-critical complaints. During the initial video visit, she appeared well, conversing normally without laboured breathing. An elevated serum D-dimer prompted CT pulmonary angiography, which identified acute lobar pulmonary embolism. After haematology consultation and telephone conversation with the patient, her physician prescribed rivaroxaban. Her symptoms rapidly improved. She had an uneventful course and is continuing anticoagulation indefinitely. The pandemic has increased the application of telemedicine for acute care complaints. This case illustrates its safe and effective use for comprehensive management of acute pulmonary embolism in the primary care setting.

To scan or not to scan - D-dimers and computed tomography pulmonary angiography in the era of COVID-19

The COVID-19 pandemic has had many ramifications on healthcare delivery and practice. As part of this, utilising biomarkers to risk stratify patients has become increasingly popular. During the COVID-19 pandemic the use of D-dimer has increased due to the evidence of COVID-19 induced thrombo-embolic disease. We evaluated the use of D-dimer on all hospital admissions during the peak of the pandemic and evaluated its sensitivity in diagnosing pulmonary embolic disease (PE). Patients without COVID-19 infection were as likely to have evidence of PE as their COVID-positive counterparts. However, the sensitivity of a D-dimer was higher in COVID-positive patients at a lower D-dimer level (>1,500 μg/L, sensitivity 81%, specificity 70%) than in those without clinical, immunological or radiological evidence of COVID-19 infection (D-dimer >2,000 μg/L, sensitivity 80%, specificity 76%). These data suggest higher D-dimer thresholds should be considered for the exclusion of pulmonary emboli.

The Positive Rate of Pulmonary Embolism by CT Pulmonary Angiography Is High in an Emergency Department, Even in Low-Risk or Young Patients

OBJECTIVE

The clinical presentation of pulmonary embolism (PE) can be various and misleading. We analyzed patients with suspicion of PE and subsequently performed computed tomography pulmonary angiography (CTPA) in an emergency department of Internal Medicine, focusing on patient groups in which PE might be underestimated in the emergency setting, such as young patients and patients with low clinical probability.

MATERIAL AND METHODS

In 2016 and 2017, all patients receiving a CTPA for investigation of PE were retrospectively evaluated for clinical parameters (age, symptoms, and vital parameters) and D-dimers. The Wells score was calculated.

RESULTS

CTPA was performed in 323 patients (158 female and 165 male; mean age 62 years). The leading symptoms for admission were dyspnea or chest pain; 62% showed intermediate or high risk for PE, calculated by applying the Wells score. In 123 (38%) of all patients, a PE was proved and pathologic age-adjusted D-dimers were found in 97.6%. Thirty of 121 (25%) patients with low risk according to Wells score had a PE. Deep vein thrombosis was verified in 67/123 (55%) patients; 43% (15/35) of all suspicions for PE in patients <40 years were positive with 4/15 (26%), showing a central PE. Younger patients (<40 years) with PE presented more often with tachycardia or tachypnea and chest pain or dyspnea than elderly patients with PE.

CONCLUSION

CTPA frequently proves a PE in patients with suspicion of PE in an emergency department of Internal Medicine. If PE is suspected and CTPA performed accordingly, the presence of PE is quite common even in low-risk patient groups (Wells score) or in young patients <40 years with chest pain or dyspnea.

Point-of-Care Testing for D-Dimer in the Diagnosis of Venous Thromboembolism in Primary Care: A Narrative Review

Venous thromboembolism (VTE) is regarded as a significant cause of mortality and disability, affecting 1-2 per 1000 people annually, presenting with a relatively wide range of symptoms, which can pose a diagnostic challenge. Historically, people in whom VTE is suspected will have been taken to hospital for diagnosis and treatment; however, a high proportion of patients are found not to have VTE. Concerns have been expressed about potential delays in treatment, with the risk of additional morbidity and disability, and death. Diagnostic strategies are typically based on the use of a clinical prediction rule to determine the pre-test probability, complemented with a measurement of D-dimer, with confirmation by imaging assessment. This narrative review explores the literature on the use of point-of-care testing (POCT) for the measurement of D-dimer, as part of a clinical decision rule, for the diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in the primary care setting. In the two main prospective management (validation) studies that included D-dimer POCT or similar technologies, with a total cohort of 1600 participants, DVT was ruled out in 49% of patients, with a false negative rate of 1.4%, whereas PE was ruled out in 45% of patients, with a false negative rate of 1.5%. This suggests that uptake of POCT D-dimer in primary care has the potential to reduce the number of referrals to hospitals for imaging confirmatory investigation, with consequent cost savings. Thus, adopting POCT for D-dimer in primary care can offer clinical and cost benefits, particularly when quantitative POCT assays are being used. Furthermore, POCT should be undertaken in collaboration with the local laboratories to ensure the harmonisation of D-dimer methods and quality assurance to improve the diagnosis of VTE.

Primary care physicians comprehensively manage acute pulmonary embolism without higher-level-of-care transfer: A report of two cases

RATIONALE

The evidence for outpatient pulmonary embolism (PE) management apart from hospitalization is expanding. The availability and ease of direct oral anticoagulants have facilitated this transition. The literature, however, is sparse on the topic of comprehensive management of pulmonary embolism in the primary care clinic setting. As such, the role of the primary care physician in the complete diagnosis, risk stratification for outpatient eligibility, and initiation of treatment is unclear.

CASE PRESENTATIONS

Case 1: A 33-year-old man with known heterozygous Factor V Leiden mutation and a remote history of deep vein thrombosis presented to his primary care physician's office with 2 days of mild pleuritic chest pain and a dry cough after a recent transcontinental flight. Case 2: A 48-year-old man with a complex medical history including recent transverse myelitis presented to his primary care family physician with dyspnea and pleuritic chest pain for 6 days.

DIAGNOSIS

Case 1: Computed tomographic pulmonary angiography that same afternoon showed multiple bilateral segmental and subsegmental emboli as well as several small pulmonary infarcts. Case 2: The patient's D-dimer was elevated at 1148 ng/mL. His physician ordered a computed tomographic pulmonary angiography, performed that evening, which showed segmental and subsegmental PE.

INTERVENTIONS

Both patients were contacted by their respective physicians shortly after their diagnoses and, in shared decision-making, opted for treatment at home with 5 days of enoxaparin followed by dabigatran.

OUTCOMES

Neither patient developed recurrence nor complications in the subsequent 3 months.

LESSONS

These cases, stratified as low risk using the American College of Chest Physicians criteria and the PE Severity Index, are among the first in the literature to illustrate comprehensive primary care-based outpatient PE management. Care was provided within an integrated delivery system with ready, timely access to laboratory, advanced radiology, and allied health services. This report sets the stage for investigating the public health implications of comprehensive primary care-based PE management, including cost-savings as well as enhanced patient follow-up and patient satisfaction.

Pulmonary Embolism: A Practical Guide for the Busy Clinician

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

An authoritative algorithm most appropriate for the prediction of pulmonary embolism in patients with AECOPD

Background

Contemporarily authoritative algorithms for the prediction of acute pulmonary embolism (PE) comprise the Standard algorithm, the Age-adjusted algorithm, the YEARS algorithm, the PERC algorithm, and the PEGeD algorithm. To date, little is known with respect to which algorithm is most appropriate for the PE prediction in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

The patients with AECOPD who underwent the confirmed chest imaging investigations of PE due to the likelihood of PE predicted by the Standard algorithm were retrospectively reviewed. The patients were reassessed by the other four algorithms to reveal which algorithm had the best diagnostic accuracy for the likelihood prediction of PE for patients with AECOPD.

Results

The results showed that the PEGeD algorithm(88.6, 80.7, 50.4, 97.0%, 4.591, 0.141, 0.693, 82.1%) performed better overall in the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, Youden index, and diagnostic accuracy, in comparison with the Age-adjusted algorithm (78.6, 74.1, 40.1, 94.0%, 3.034, 0.289, 0.527, 74.9%), the YEARS algorithm (71.4, 76.6, 40.3, 92.4%, 3.051, 0.373, 0.480,75.6%), the PERC algorithm (98.6, 1.6, 18.2, 83.3%, 1.002, 0.875, 0.002, 19.2%). The difference of number of patients who were necessary to undergo chest imaging examinations and missed diagnoses resulted from each algorithm between the PEGeD algorithm and the Standard algorithm, the Age-adjusted algorithm, the YEARS algorithm, as well as the PERC algorithm were [− 789 (− 68.1%), N/A], [− 42 (− 3.6%),-21 (− 1.8%)], [− 3 (− 0.3%),-36 (− 3.1%)],[− 771 (− 66.6%), 21 (1.8%)], respectively.

Conclusions

To date, the PEGeD algorithm is the most appropriate strategy among the authoritative algorithms for the likelihood prediction of pulmonary embolism in patients with AECOPD.

The association between pulmonary embolism and the cancer-related genomic alterations in patients with NSCLC

To date, the association between the acute pulmonary embolism (PE) and the currently existing cancer-related genomic alterations in patients with non-small cell lung cancer (NSCLC) has been understudied. We reviewed patients with a confirmed histopathological diagnosis of NSCLC who underwent computed tomography pulmonary angiography (CTPA) and molecular tests including ALK, ROS1, EGFR, BRAF V600E as well as PD-L1 during the diagnosis of NSCLC, to explore the association between the genomic alterations and PE. The results showed that, for the patients with positive results of genomic alterations, the proportion of positive ALK (13.6%vs8.5%, P<0.001) and PD-L1 (24.7%vs19.9%, P = 0.001) in PE group were more than those in Non-PE group. The patients with positive ALK and PD-L1 had the most (19.0%) and second most (15.4%) incidence of PE among all the patients being studied. A multivariate Logistic regression analysis showed that the positive ALK [1.685(1.065-2.215)(P<0.001)] and PD-L1[1.798(1.137-2.201)(P<0.001)] were correlated with the occurrence of PE. The positive results of ALK and PD-L1 genomic alterations may indicate an increased risk of pulmonary embolism in patients with NSCLC.

Comprehensive Outpatient Management of Low-Risk Pulmonary Embolism: Can Primary Care Do This? A Narrative Review

INTRODUCTION

The evidence for outpatient management of hemodynamically stable, low-risk patients with acute symptomatic pulmonary embolism (PE) is mounting. Guidance in identifying patients who are eligible for outpatient (ambulatory) care is available in the literature and society guidelines. Less is known about who can identify patients eligible for outpatient management and in what clinical practice settings.

OBJECTIVE

To answer the question, "Can primary care do this?" (provide comprehensive outpatient management of low-risk PE).

METHODS

We undertook a narrative review of the literature on the outpatient management of acute PE focusing on site of care. We searched the English-language literature in PubMed and Embase from January 1, 1950, through July 15, 2019.

RESULTS

We identified 26 eligible studies. We found no studies that evaluated comprehensive PE management in a primary care clinic or general practice setting. In 19 studies, the site-of-care decision making occurred in the Emergency Department (or after a short period of supplemental observation) and in 7 studies the decision occurred in a specialty clinic. We discuss the components of care involved in the diagnosis, outpatient eligibility assessment, treatment, and follow-up of ambulatory patients with acute PE.

DISCUSSION

We see no formal reason why a trained primary care physician could not provide comprehensive care for select patients with low-risk PE. Leading obstacles include lack of ready access to advanced pulmonary imaging and the time constraints of a busy outpatient clinic.

CONCLUSION

Until studies establish safe parameters of such a practice, the question "Can primary care do this?" must remain open.

A systematic review of methodology used in the development of prediction models for future asthma exacerbation

Background

Clinical prediction models are widely used to guide medical advice and therapeutic interventions. Asthma is one of the most common chronic diseases globally and is characterised by acute deteriorations. These exacerbations are largely preventable, so there is interest in using clinical prediction models in this area. The objective of this review was to identify studies which have developed such models, determine whether consistent and appropriate methodology was used and whether statistically reliable prognostic models exist.

Methods

We searched online databases MEDLINE (1948 onwards), CINAHL Plus (1937 onwards), The Cochrane Library, Web of Science (1898 onwards) and ClinicalTrials.gov, using index terms relating to asthma and prognosis. Data was extracted and assessment of quality was based on GRADE and an early version of PROBAST (Prediction study Risk of Bias Assessment Tool). A meta-analysis of the discrimination and calibration measures was carried out to determine overall performance across models.

Results

Ten unique prognostic models were identified. GRADE identified moderate risk of bias in two of the studies, but more detailed quality assessment via PROBAST highlighted that most models were developed using highly selected and small datasets, incompletely recorded predictors and outcomes, and incomplete methodology. None of the identified models modelled recurrent exacerbations, instead favouring either presence/absence of an event, or time to first or specified event. Preferred methodologies were logistic regression and Cox proportional hazards regression.

The overall pooled c-statistic was 0.77 (95% confidence interval 0.73 to 0.80), though individually some models performed no better than chance. The meta-analysis had an I² value of 99.75% indicating a high amount of heterogeneity between studies. The majority of studies were small and did not include internal or external validation, therefore the individual performance measures are likely to be optimistic.

Conclusions

Current prognostic models for asthma exacerbations are heterogeneous in methodology, but reported c-statistics suggest a clinically useful model could be created. Studies were consistent in lacking robust validation and in not modelling serial events. Further research is required with respect to incorporating recurrent events, and to externally validate tools in large representative populations to demonstrate the generalizability of published results.

Effect of Beta-blockers on Tachycardia in Patients with Pulmonary Embolism

Hypothesis Beta-blockers (BBs) lower the heart rate, which may mask the diagnosis of pulmonary embolism (PE) since one of the main clinical diagnoses of PE is tachycardia. The endpoint of our retrospective study is to determine if the pre-existing use of (BB) significantly affects the utility of these scoring criteria in diagnosing PE. Introduction Diagnosing PE is a challenge because of the non-specificity of its symptoms and signs. The initial step is to assess the patient's likelihood of having a PE. This involves using a scoring system to stratify patients into different levels of risk of having PE (for example, as 'low,' 'moderate,' or 'high' risk). Some of the commonly used criteria are Wells' Score, Geneva Score, and Pulmonary Embolism Rule-out Criteria (PERC) Rule (Charlotte Rule). Methodology This retrospective study was conducted at St. Francis Medical Center. Subjects were taken from a patient population with a new diagnosis of PE (between 2010 and 2017) on the basis of computed tomography angiography (CTA) of the chest. Patients with sepsis or septic shock, heart block, atrioventricular (AV) nodal ablation, pacemaker placement, or taking more than one AV nodal blocker were excluded from the study. Subjects were categorized on the basis of beta-blocker consumption. Result Out of a total of 170 cases, 71 patients were taking beta-blockers and 99 patients were not taking beta-blockers. Among the participants taking BBs, 30.4% had a heart rate <60 and 55.8% had a heart rate between 60 and 100. Conclusion BBs significantly obviate tachycardia in patients with PE. It falsely decreases the Wells' Score and the Geneva Score and results in the inappropriate fulfilling of PERC criteria.

A comparative analysis of the diagnostic performances of four clinical probability models for acute pulmonary embolism in a sub-Saharan African population: a cross-sectional study

Background

The diagnosis of acute pulmonary embolism (PE) is one of the most challenging in emergency settings where prompt and accurate decisions need to be taken for life-saving purposes. Here, the assessment of the clinical probability of PE is a paramount step in its diagnosis. Although clinical probability models (CPM) for PE are routinely used in emergency departments (EDs) of low-resource settings, few studies have cited their diagnostic performances in sub-Saharan Africa (SSA). We aimed to comparatively assess the accuracy of four CPM in the diagnosis of acute PE in sub-Saharan Africans.

Methods

We carried out a cross-sectional study to compare the sensitivity, specificity, positive and negative predictive values and accuracy of four CPM namely; the Wells, simplified Wells, revised Geneva and the simplified revised Geneva (SRG) Scores to computed tomography pulmonary angiography (CTPA) in all adults patients with suspected PE admitted to the EDs of the Gynaeco-obstetric and Paediatric Hospital of Yaoundé and the Yaoundé Central Hospital in Cameroon between January 1, 2017 and April 30, 2018.

Results

In total, we enrolled 30 patients with clinical suspicion of acute PE. PE was confirmed on CTPA in 16 (53.3%) cases. Their mean age was 53.7 ± 15.5 years and 36.7% were males. All four scores had a diagnostic performance superior to 50% in all criteria assessed. The simplified Wells score had the highest sensitivity (62.5%) followed by the Wells score (56.3%). The SRG score had the highest specificity (71.4%). The score with highest PPV was the SRG score (66.7%) and that with the highest NPV was the Wells score (56.3%). Overall the models with the highest accuracies were the Wells and SRG scores (60% for each).

Conclusion

All CPM had a suboptimal diagnostic performance, perhaps highlighting the need of a more optimal CPM for acute PE in SSA. However, the Wells and the SRG scores appeared to be most accurate than the other two scores in the ED. Hence, both or either of them may be used in first intention to predict PE and guide which ED patients should undergo further investigations in an emergency SSA setting.

Diagnosis of Pulmonary Embolism with d-Dimer Adjusted to Clinical Probability

BACKGROUND

Retrospective analyses suggest that pulmonary embolism is ruled out by a d-dimer level of less than 1000 ng per milliliter in patients with a low clinical pretest probability (C-PTP) and by a d-dimer level of less than 500 ng per milliliter in patients with a moderate C-PTP.

METHODS

We performed a prospective study in which pulmonary embolism was considered to be ruled out without further testing in outpatients with a low C-PTP and a d-dimer level of less than 1000 ng per milliliter or with a moderate C-PTP and a d-dimer level of less than 500 ng per milliliter. All other patients underwent chest imaging (usually computed tomographic pulmonary angiography). If pulmonary embolism was not diagnosed, patients did not receive anticoagulant therapy. All patients were followed for 3 months to detect venous thromboembolism.

RESULTS

A total of 2017 patients were enrolled and evaluated, of whom 7.4% had pulmonary embolism on initial diagnostic testing. Of the 1325 patients who had a low C-PTP (1285 patients) or moderate C-PTP (40 patients) and a negative d-dimer test (i.e., <1000 or <500 ng per milliliter, respectively), none had venous thromboembolism during follow-up (95% confidence interval [CI], 0.00 to 0.29%). These included 315 patients who had a low C-PTP and a d-dimer level of 500 to 999 ng per milliliter (95% CI, 0.00 to 1.20%). Of all 1863 patients who did not receive a diagnosis of pulmonary embolism initially and did not receive anticoagulant therapy, 1 patient (0.05%; 95% CI, 0.01 to 0.30) had venous thromboembolism. Our diagnostic strategy resulted in the use of chest imaging in 34.3% of patients, whereas a strategy in which pulmonary embolism is considered to be ruled out with a low C-PTP and a d-dimer level of less than 500 ng per milliliter would result in the use of chest imaging in 51.9% (difference, -17.6 percentage points; 95% CI, -19.2 to -15.9).

CONCLUSIONS

A combination of a low C-PTP and a d-dimer level of less than 1000 ng per milliliter identified a group of patients at low risk for pulmonary embolism during follow-up. (Funded by the Canadian Institutes of Health Research and others; PEGeD ClinicalTrials.gov number, NCT02483442.).

Is Bedside End-Tidal CO2 Measurement a Screening Tool to Exclude Pulmonary Embolism in Emergency Department?

Background

Pulmonary embolism (PE) is among the most difficult conditions to diagnose in emergency department. The majority of patients thought to have PE are tested positive for D-dimer and subsequently tested with advanced diagnostic modalities. Novel noninvasive tests capable of excluding PE may obviate the need for advanced imaging tests. We studied the role of combined clinical probability assessment and end-tidal carbon dioxide (ETCO₂) measurement for diagnosis of possible PE in emergency department.

Methods

We included 100 consecutive subjects suspected to have PE and a positive D-dimer test to study clinical probability of PE and ETCO₂ levels. ETCO₂ > 34 mm Hg was found to be the best cut-off point for diagnosing PE. PE was ultimately eliminated or diagnosed by spiral computed tomography (CT).

Results

Diagnostic performances of tests were as follows: ETCO₂ and D-dimer had a sensitivity of 100% and a negative predictive value (NPV) of 100% at the cut-off levels of 34 mm Hg and 500 ng/mL, respectively; Wells score had a sensitivity of 80% and NPV of 69.7% at a score of 4.

Conclusions

ETCO₂ alone cannot reliably exclude PE. Combining it with clinical probability, however, reliably and correctly eliminates or diagnoses PE and prevents further testing to be done.

Validity of four clinical prediction scores for pulmonary embolism in a sub-Saharan African setting: a protocol for a Cameroonian multicentre cross-sectional study

INTRODUCTION

Pulmonary embolism poses one of the most challenging diagnoses in medicine. Resolving these diagnostic difficulties is more crucial in emergency departments where fast and accurate decisions are needed for a life-saving purpose. Here, clinical pretest evaluation is an important step in the diagnostic algorithm of pulmonary embolism. Although clinical probability scores are widely used in emergency departments of sub-Saharan Africa, no study has cited their diagnostic performance in this resource-constrained environment. This study will seek to assess the performance of four routinely used clinical prediction models in Cameroonians presenting with suspicion of pulmonary embolism at the emergency department.

METHODS AND ANALYSIS

It will be a cross-sectional study comparing the sensitivity, specificity, positive and negative predictive values and accuracy of the Wells, Simplified Wells, Revised Geneva and the Simplified Revised Geneva Scores to CT pulmonary angiography as gold standard in all consecutive consenting patients aged above 15 years admitted for clinical suspicion of pulmonary embolism to the emergency departments of seven major referral hospitals of Cameroon between 1 July 2019 and 31 December 2020. The area under the receiver operating curve, calibration plots, Hosmer and Lemeshow statistics, observed/expected event rates, net benefit and decision curve will be measured of each the clinical prediction test to ascertain the clinical score with the best diagnostic performance.

ETHICS AND DISSEMINATION

Clearance has been obtained from the Institutional Review Board of the Faculty of medicine and biomedical sciences of the University of Yaounde I, Cameroon and the directorates of all participating hospitals to conduct this study. Also, informed consent will be sought from each patient or their legal next of kin and parents for minors, before enrolment into this study. The final study will be published in a peer-review journal and the findings presented to health authorities and healthcare providers.

Relationship of Lower-extremity Deep Venous Thrombosis Density at CT Venography to Acute Pulmonary Embolism and the Risk of Postthrombotic Syndrome

Background Acute deep venous thrombi (DVT) have higher Hounsfield unit values than chronic (bland) thrombi at CT venography. Purpose To determine the relationship between DVT thrombus density found on CT venography images to the presence of acute pulmonary embolism (PE) and the future risk of postthrombotic syndrome (PTS) in patients with DVT. Materials and Methods In this retrospective study, patients were divided into two groups: PE with DVT group and DVT-only group. Wells scores were recorded. Thrombus density ratios were calculated (DVT thrombus Hounsfield units/surrounding vein Hounsfield units). The presence or absence of PTS was determined from the results of the Venous Insufficiency Epidemiologic and Economic Study on Quality of Life (VEINES-QOL) questionnaires given to the patients with DVT. Statistical analyses used receiver operating characteristic curves and Spearman correlation analyses. Results Eighty-six patients were included; the mean age was 60 years ± 17 (51 men; PE with DVT group, 54 patients [63%]; DVT-only group, 32 patients [37%]). The mean thrombus density ratio was significantly higher in the PE with DVT group than in the DVT-only group (53.6% ± 12.4 [standard deviation] vs 42.8% ± 11.9, respectively; P < .001). At multivariable analysis, Wells score greater than 4 (odds ratio, 12.0; 95% confidence interval [CI]: 3.0, 47; P < .001) and higher thrombus density ratio (odds ratio, 1.1; 95% CI: 1.0, 1.2; P = .001) were independent predictors of PE. The diagnostic performance for the thrombus density ratio (area under the receiver operating characteristic curve, 0.74; 95% CI: 0.63, 0.85; P < .001) may be more discriminative than that of the Wells score (area under the receiver operating characteristic curve, 0.70; 95% CI: 0.59, 0.81; P = .002) for the presence of PE. In subgroup analysis, the thrombus density ratio and VEINES-QOL score were correlated (r = 0.61; 95% CI: 0.30, 0.80; P < .001). Conclusion Deep venous thrombosis (DVT) density ratio at CT venography was associated with acute pulmonary embolism in patients with lower-extremity DVT. © RSNA, 2019 Online supplemental material is available for this article.

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

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

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.

Fatal recurrent VTE after anticoagulant treatment for unprovoked VTE: a systematic review

Current guidelines recommend long-term anticoagulant therapy in patients with unprovoked venous thromboembolism (VTE). The risk of fatal recurrent VTE after treatment discontinuation (versus that of fatal bleeding during anticoagulation) is of particular relevance in the decision to continue or stop anticoagulation after the first 3 months. Our primary aim was to provide a point-estimate of the yearly rate of fatal recurrent VTE and VTE case-fatality rate in patients with unprovoked VTE after anticoagulation cessation. Data were extracted from both randomised controlled trials and observational studies published before May 1, 2017. The pooled fatality rates were calculated using a random-effects model. 18 studies with low-to-moderate bias were included in the primary analysis, totalling 6758 patients with a median (range) follow-up duration of 2.2 (1–5) years. After anticoagulation cessation, the weighted pooled rate of VTE recurrence was 6.3 (95% CI 5.4–7.3) per 100 patient-years and the weighted pooled rate of fatal recurrent VTE was 0.17 (95% CI 0.047–0.33) per 100 patient-years, for a case-fatality rate of 2.6% (95% CI 0.86–5.0). These numbers are a solid benchmark for comparison to the risks associated with long-term anticoagulation treatment for the decision on the optimal duration of treatment of patients with unprovoked VTE.

Value of MRI in medicine: More than just another test?

There is increasing scrutiny from healthcare organizations towards the utility and associated costs of imaging. MRI has traditionally been used as a high-end modality, and although shown extremely important for many types of clinical scenarios, it has been suggested as too expensive by some. This editorial will try and explain how value should be addressed and gives some insights and practical examples of how value of MRI can be increased. It requires a global effort to increase accessibility, value for money, and impact on patient management. We hope this editorial sheds some light and gives some indications of where the field may wish to address some of its research to proactively demonstrate the value of MRI. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;49:e14-e25.

The sensitivities and prognostic values of the Wells and revised Geneva scores in diagnosis of pulmonary embolism in the Japanese population

OBJECTIVE

To assess the sensitivities of the Wells score (WS) and the revised Geneva score (RGS) and their prognostic values in the diagnosis of pulmonary embolism (PE) in the Japanese population.

METHODS

We conducted a retrospective chart review of patients with PE aged 16 years or older who were assessed between December 2008 and August 2014. Patients were divided into the PE unlikely and PE likely groups according to the WS and PE unlikely and PE likely groups according to the RGS. We also described the characteristics and three-month mortality of the patients. Univariate predictors with p < 0.05 were included in the multiple regression model. Fisher׳s exact test and Student׳s t-test were used for categorical and continuous variables, respectively.

RESULTS

PE was confirmed in 53 patients, and seven (13%) patients died within 3 months. The mean age was 66.0 ± 14.4 years. There were 32 female patients (60.4%). The RGS had a higher sensitivity than the WS (20.8% vs. 15.1%, P <0.01), although both scores had low yields. Mortality rate was significantly higher in patients with syncope than in those without (33.3% vs. 7.3%, respectively; P = 0.039). After age and sex adjustments, the presence of syncope showed a statistically significant association with mortality. The mortality rate did not significantly differ between the two groups categorized according to the WS (17.4% vs. 0%; P = 0.58) and RGS (21.7% vs. 14.3%; P = 1.00).

CONCLUSION

WS and RGS had low sensitivity in the diagnosis of PE and had limited prognostic values in a Japanese community hospital setting. Promoting awareness about the risk of mortality in patients with PE, especially those with syncope, is necessary.

Ruling out Pulmonary Embolism in Patients with High Pretest Probability

Introduction

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

Methods

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

Results

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

Conclusion

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

Diagnosis and Management of VTE in Pregnancy

Venous thromboembolism is a leading cause of maternal death. Because of the low absolute frequency of events, however, outcome-based clinical data are limited. Consequently, clinicians must additionally rely both on published guidelines and on extrapolation of data from studies focused on nonpregnant individuals. The diagnosis and treatment of deep vein thrombosis, pulmonary embolism, and cerebral vein and dural sinus thrombosis are complicated by pregnancy, and often require modifications to standard diagnostic and treatment algorithms outside of pregnancy. Treatment of VTE in pregnant women is in particular need of future research.

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.

Ruling out pulmonary embolism across different subgroups of patients and healthcare settings: protocol for a systematic review and individual patient data meta-analysis (IPDMA)

BACKGROUND

Diagnosing pulmonary embolism in suspected patients is notoriously difficult as signs and symptoms are non-specific. Different diagnostic strategies have been developed, usually combining clinical probability assessment with D-dimer testing. However, their predictive performance differs across different healthcare settings, patient subgroups, and clinical presentation, which are currently not accounted for in the available diagnostic approaches.

METHODS

This is a protocol for a large diagnostic individual patient data meta-analysis (IPDMA) of currently available diagnostic studies in the field of pulmonary embolism. We searched MEDLINE (search date January 1, 1995, till August 25, 2016) to retrieve all primary diagnostic studies that had evaluated diagnostic strategies for pulmonary embolism. Two authors independently screened titles, abstracts, and subsequently full-text articles for eligibility from 3145 individual studies. A total of 40 studies were deemed eligible for inclusion into our IPDMA set, and principal investigators from these studies were invited to participate in a meeting at the 2017 conference from the International Society on Thrombosis and Haemostasis. All authors agreed on data sharing and participation into this project. The process of data collection of available datasets as well as potential identification of additional new datasets based upon personal contacts and an updated search will be finalized early 2018. The aim is to evaluate diagnostic strategies across three research domains: (i) the optimal diagnostic approach for different healthcare settings, (ii) influence of comorbidity on the predictive performance of each diagnostic strategy, and (iii) optimize and tailor the efficiency and safety of ruling out PE across a broad spectrum of patients with a new, patient-tailored clinical decision model that combines clinical items with quantitative D-dimer testing.

DISCUSSION

This pre-planned individual patient data meta-analysis aims to contribute in resolving remaining diagnostic challenges of time-efficient diagnosis of pulmonary embolism by tailoring available diagnostic strategies for different healthcare settings and comorbidity.

SYSTEMATIC REVIEW REGISTRATION

Prospero trial registration: ID 89366.

A Test in Context: D-Dimer

D-dimer is a soluble fibrin degradation product that results from ordered breakdown of thrombi by the fibrinolytic system. Numerous studies have shown that D-dimer serves as a valuable marker of activation of coagulation and fibrinolysis. Consequently, D-dimer has been extensively investigated for the diagnosis of venous thromboembolism (VTE) and is used routinely for this indication. In addition, D-dimer has been evaluated for determining the optimal duration of anticoagulation in VTE patients, for diagnosing and monitoring disseminated intravascular coagulation, and as an aid in the identification of medical patients at high risk for VTE. Thus, quantification of D-dimer levels serves an important role in guiding therapy. This review: 1) describes how D-dimer is generated; 2) reviews the assays used for its detection; and 3) discusses the role of D-dimer determination in these various conditions.

Comparison of clinical probability-adjusted D-dimer and age-adjusted D-dimer interpretation to exclude venous thromboembolism

Two new strategies for interpreting D-dimer results have been proposed: i) using a progressively higher D-dimer threshold with increasing age (age-adjusted strategy) and ii) using a D-dimer threshold in patients with low clinical probability that is twice the threshold used in patients with moderate clinical probability (clinical probability-adjusted strategy). Our objective was to compare the diagnostic accuracy of age-adjusted and clinical probability-adjusted D-dimer interpretation in patients with a low or moderate clinical probability of venous thromboembolism (VTE). We performed a retrospective analysis of clinical data and blood samples from two prospective studies. We compared the negative predictive value (NPV) for VTE, and the proportion of patients with a negative D-dimer result, using two D-dimer interpretation strategies: the age-adjusted strategy, which uses a progressively higher D-dimer threshold with increasing age over 50 years (age in years × 10 µg/L FEU); and the clinical probability-adjusted strategy which uses a D-dimer threshold of 1000 µg/L FEU in patients with low clinical probability and 500 µg/L FEU in patients with moderate clinical probability. A total of 1649 outpatients with low or moderate clinical probability for a first suspected deep vein thrombosis or pulmonary embolism were included. The NPV of both the clinical probability-adjusted strategy (99.7%) and the age-adjusted strategy (99.6%) were similar. However, the proportion of patients with a negative result was greater with the clinical probability-adjusted strategy (56.1% vs, 50.9%; difference 5.2%; 95% CI 3.5% to 6.8%). These findings suggest that clinical probability-adjusted D-dimer interpretation is a better way of interpreting D-dimer results compared to age-adjusted interpretation.

Age-adjusted D-dimer cut-off in the diagnostic strategy for deep vein thrombosis: a systematic review

BACKGROUND

Studies have indicated that use of an age-adjusted D-dimer cut-off value for patients above 50 years increases utility of the diagnostic strategy for pulmonary embolism. Evidence for the same approach regarding diagnosis of deep vein thrombosis (DVT) is, however, unclear.

MATERIALS AND METHODS

A systematic literature review was conducted following the PRISMA Statement guideline to gather the existing knowledge on the use of an age-adjusted D-dimer cut-off in the diagnostic strategy for DVT. Studies were extracted from Medline and the Cochrane Library. The search period ended in November 2016.

RESULTS

Out of 73 articles retrieved, only eight studies addressed DVT either specifically or along with PE. None of these were randomized controlled trials, but were either prospective studies of consecutive outpatients or retrospective studies. Despite differences in study design, DVT prevalence, and D-dimer assay used, all studies were in favour of the age-adjusted D-dimer cut-off with negative predictive values (NPV) ranging from 91.8-100% compared to 89.7-100% for the standard D-dimer cut-off. All the studies concluded that use of an age-adjusted D-dimer cut-off resulted in an improved utility, although the results due to heterogeneity in reporting did not allow a direct comparison.

CONCLUSION

Use of an age-adjusted D-dimer cut-off for patients above 50 years of age for ruling out DVT seems as safe as using a standard D-dimer cut-off. The recommended (and most used) adjustment is by the formula (patient's age ×10) μg/L.

The original and simplified Wells rules and age-adjusted D-dimer testing to rule out pulmonary embolism: an individual patient data meta-analysis

Essentials Evidence for the simplified Wells rule in ruling out acute pulmonary embolism (PE) is scarce. This was a post-hoc analysis on data from 6 studies comprising 7268 patients with suspected PE. The simplified Wells rule combined with age-adjusted D-dimer testing may safely rule out PE. Given its ease of use, the simplified Wells rule is to be preferred over the original Wells rule.

SUMMARY

Background The Wells score and D-dimer testing can safely rule out pulmonary embolism (PE). A simplification of the Wells score has been proposed to improve clinical applicability, but evidence on its performance is scarce. Objectives To compare the performances of the original and simplified Wells scores alone and in combination with age-adjusted D-dimer testing. Methods Individual patient data from 7268 patients with suspected PE enrolled in six management studies were used to evaluate the discriminatory performances of the original and simplified Wells scores. The efficiency and failure rate of the dichotomized original and simplified scores combined with age-adjusted D-dimer testing were compared by use of a one-stage random effects meta-analysis. Efficiency was defined as the proportion of patients in whom PE could be considered to be excluded on the basis of a 'PE unlikely' Wells score and a negative age-adjusted D-dimer test result. Failure rate was defined as the proportion of patients with symptomatic venous thromboembolism during a 3-month follow-up. Results The discriminatory performances of the original and simplified Wells scores were comparable (c-statistic 0.73 [95% confidence interval (CI) 0.72-0.75] versus 0.72 [95% CI 0.70-0.73]). When combined with age-adjusted D-dimer testing, the original and simplified Wells rules had comparable efficiency (3% [95% CI 25-42%] versus 30% [95% CI 21-40%]) and failure rates (0.9% [95% CI 0.6-1.5%] versus 0.8% [95% CI 0.5-1.3%]). Conclusion The original and simplified Wells rules combined with age-adjusted D-dimer testing have similar performances in ruling out PE. Given its ease of use in clinical practice, the simplified Wells rule is to be preferred.

Modelling idiopathic Parkinson disease as a complex illness can inform incidence rate in healthy adults: the PR EDIGT score

Fifty-five years after the concept of dopamine replacement therapy was introduced, Parkinson disease (PD) remains an incurable neurological disorder. To date, no disease-modifying therapeutic has been approved. The inability to predict PD incidence risk in healthy adults is seen as a limitation in drug development, because by the time of clinical diagnosis ≥ 60% of dopamine neurons have been lost. We have designed an incidence prediction model founded on the concept that the pathogenesis of PD is similar to that of many disorders observed in ageing humans, i.e. a complex, multifactorial disease. Our model considers five factors to determine cumulative incidence rates for PD in healthy adults: (i) DNA variants that alter susceptibility (D), e.g. carrying a LRRK2 or GBA risk allele; (ii) Exposure history to select environmental factors including xenobiotics (E); (iii) Gene-environment interactions that initiate pathological tissue responses (I), e.g. a rise in ROS levels, misprocessing of amyloidogenic proteins (foremost, α-synuclein) and dysregulated inflammation; (iv) sex (or gender; G); and importantly, (v) time (T) encompassing ageing-related changes, latency of illness and propagation of disease. We propose that cumulative incidence rates for PD (PR ) can be calculated in healthy adults, using the formula: PR (%) = (E + D + I) × G × T. Here, we demonstrate six case scenarios leading to young-onset parkinsonism (n = 3) and late-onset PD (n = 3). Further development and validation of this prediction model and its scoring system promise to improve subject recruitment in future intervention trials. Such efforts will be aimed at disease prevention through targeted selection of healthy individuals with a higher prediction score for developing PD in the future and at disease modification in subjects that already manifest prodromal signs.

Diagnosis of suspected venous thromboembolism

The primary goal of diagnostic testing for venous thromboembolism (VTE) is to identify all patients who could benefit from anticoagulant therapy. Test results that identify patients as having a ≤2% risk of VTE in the next 3 months are judged to exclude deep vein thrombosis (DVT) or pulmonary embolism (PE). Clinical evaluation, with assessment of: (1) clinical pretest probability (CPTP) for VTE; (2) likelihood of important alternative diagnoses; and (3) the probable yield of D-dimer and various imaging tests, guide which tests should be performed. The combination of nonhigh CPTP and negative D-dimer testing excludes DVT or PE in one-third to a half of outpatients. Venous ultrasound of the proximal veins, with or without examination of the distal veins, is the primary imaging test for leg and upper-extremity DVT. If a previous test is not available for comparison, the positive predictive value of ultrasound is low in patients with previous DVT. Computed tomography pulmonary angiography (CTPA) is the primary imaging test for PE and often yields an alternative diagnosis when there is no PE. Ventilation-perfusion scanning is associated with less radiation exposure than CTPA and is preferred in younger patients, particularly during pregnancy. If DVT or PE cannot be "ruled-in" or "ruled-out" by initial diagnostic testing, patients can usually be managed safely by: (1) withholding anticoagulant therapy; and (2) doing serial ultrasound examinations to detect new or extending DVT.