Towards a tailored diagnostic standard for future diagnostic studies in pulmonary embolism: communication from the SSC of the ISTH

Validating the safety of low-dose CTPA in pregnancy: results from the OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) Study

BACKGROUND

Pulmonary embolism (PE) is a leading cause of pregnancy-related mortality. CT pulmonary angiogram (CTPA) is the first-line advanced imaging modality for suspected PE in pregnancy at institutes offering low-dose techniques; however, a protocol balancing safety with low dose remains undefined. The wide range of CTPA doses reported in pregnancy suggests a lack of confidence in implementing low-dose techniques in this group.

PURPOSE

To define and validate the safety, radiation dose and image quality of a low-dose CTPA protocol optimised for pregnancy.

MATERIALS AND METHODS

The OPTICA study is a prospective observational study. Pregnant study participants with suspected PE underwent the same CTPA protocol between May 2018 and February 2022. The primary outcome, CTPA safety, was judged by the reference standard; the 3-month incidence of venous thromboembolism (VTE) in study participants with a negative index CTPA. Secondary outcomes defined radiation dose and image quality. Absorbed breast, maternal effective and fetal doses were estimated by Monte-Carlo simulation on gestation-matched phantoms. Image quality was assessed by signal-to-noise and contrast-to-noise ratios and a Likert score for pulmonary arterial enhancement.

RESULTS

A total of 116 CTPAs were performed in 113 pregnant women of which 16 CTPAs were excluded. PE was diagnosed on 1 CTPA and out-ruled in 99. The incidence of recurrent symptomatic VTE was 0.0% (one-sided 95% CI, 2.66%) at follow-up. The mean absorbed breast dose was 2.9 ± 2.1mGy, uterine/fetal dose was 0.1 ± 0.2mGy and maternal effective dose was 1.4 ± 0.9mSv. Signal-to-noise ratio (SNR) was 11.9 ± 3.7. Contrast-to-noise ratio (CNR) was 10.4 ± 3.5.

CONCLUSION

The OPTICA CTPA protocol safely excluded PE in pregnant women across all trimesters, with low fetal and maternal radiation.

CLINICAL RELEVANCE

OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) is the first prospective study to define the achievable radiation dose, image-quality and safety of a low-dose CT pulmonary angiogram protocol optimised for pregnancy (NCT04179487). It provides the current benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population.

KEY POINTS

• Despite the increased use of CT pulmonary angiogram in pregnancy, an optimised low-dose protocol has not been defined and reported doses in pregnancy continue to vary widely. • The OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) study prospectively defines the achievable dose, image quality and safety of a low-dose CT pulmonary angiogram protocol using widely available technology. • OPTICA provides a benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population.

Utility of ultrasound in the diagnostic work-up of suspected pulmonary embolism: an open-label multicentre randomized controlled trial (the PRIME study)

Background

Prevalence of pulmonary embolism (PE) in patients referred to diagnostic imaging is decreasing, indicating a need for improving patient selection. The aim of this study was to assess reduction in referral to diagnostic imaging by integrating a bespoke ultrasound protocol and describe associated failure rate and adverse events in patients with suspected PE.

Methods

In a randomized open-label multicentre trial spanning June 18, 2021, through Feb 1, 2023, adult patients with suspected PE and 1) a Wells score of 0-6 and elevated age-adjusted D-dimer or 2) Wells score >6 were randomly assigned 1:1 to direct diagnostic imaging (controls) or focused lung, cardiac, and deep venous ultrasound by unblinded investigators. Ultrasound could: 1) dismiss PE if no signs of PE and low clinical suspicion or an alternate diagnosis, 2) confirm PE in case of visible venous thrombus, ≥2 subpleural infarctions, McConnell's, or D-sign, or 3) refer to diagnostic imaging if neither category was fulfilled or a patient with confirmed PE by ultrasound required admission. Primary endpoint was proportion of patients referred to diagnostic imaging. Outcome assessors were not blinded to group assignment. All included participants were included in safety analyses. The trial was registered at clinicaltrials.gov (NCT04882579).

Findings

A total of 150 patients were recruited, of whom 73 were randomized to ultrasound. Among 77 controls referred to diagnostic imaging, 26 patients had PE confirmed. In the ultrasound group, 40 patients were referred to diagnostic imaging of whom 20 had PE, reducing referral for diagnostic imaging by 45.2% (95% CI: 34.3-56.6, p < 0.0001). Three further PEs were diagnosed by presence of a DVT. During 3-month follow-up, the number of patients who did not receive anticoagulation but was diagnosed with PE was two (4%; 95% CI: 1.1-13.5) and none (0%; 95% CI: 0.0-7.0) in the ultrasound and control group, respectively.

Interpretation

Ultrasound substantially reduced referral to diagnostic imaging in suspected PE. Albeit with an unacceptable failure rate.

Funding

University of Southern Denmark, Odense University Hospital, Master Carpenter Sophus Jacobsen and wife's foundation, Engineer K. A. Rhode and wife foundation.

Pulmonary Embolism in Pregnancy: A Review for Clinical Practitioners

Diagnostic and therapeutic decision-making in pregnancy with suspected pulmonary embolism (PE) is challenging. European and other international professional societies have proposed various recommendations that are ambiguous, probably due to the unavailability of randomized controlled trials. In the following sections, we discuss the supporting diagnostic steps and treatments. We suggest a standardized diagnostic work-up in pregnant patients presenting with symptoms of PE to make evidence-based diagnostic and therapeutic decisions. We strongly recommend that clinical decisions on treatment in pregnant patients with intermediate- or high-risk pulmonary embolism should include a multidisciplinary team approach involving emergency physicians, pulmonologists, angiologist, cardiologists, thoracic and/or cardiovascular surgeons, radiologists, and obstetricians to choose a tailored management option including an interventional treatment. It is important to be aware of the differences among guidelines and to assess each case individually, considering the specific views of the different specialties. This review summarizes key concepts of the diagnostics and acute management of pregnant women with suspected PE that are supportive for the clinician on duty.

D-dimer Levels for the exclusion of pulmonary embolism: making sense of international guideline recommendations

Several international guidelines provide recommendations around the use of D-dimer testing for exclusion of pulmonary embolism, including the appropriate D-dimer threshold (or cutoff), but there is no consensus among them. We briefly discuss guideline variation, performance characteristics, and limitations of commercially available D-dimer assays in this setting, referencing the Clinical and Laboratory Standards Institute guidelines that recommend immunoassays with high sensitivity (≥97%) and negative predictive value (≥98%). While age-adjusted D-dimer and pretest-adjusted D-dimer are considered a safe strategy across predefined patient subgroups, clinicians need to recognize the different performance characteristics of D-dimer assays to enable safe clinical decisions for their patients. Importantly, D-dimer values must be correlated not only to clinical findings but also interpreted within the context of the accuracy and precision of the specific testing modality, adhering to manufacturer specifications that are approved by regulatory authorities.

External validation of the CHEDDAR score for suspected pulmonary embolism in patients with SARS-CoV-2 infection in an independent cohort

The accuracy of the classic scores that help stratify the pretest clinical probability of pulmonary embolism (PE) in SARS-CoV-2 infection (COVID-19) is low. Therefore, to estimate the risk of PE in these patients, a new set of guidelines must be established. The recently published CHEDDAR score proposes a new diagnostic strategy to reduce the use of computed tomography pulmonary angiography (CTPA) in non-critically ill SARS-COV-2 patients with suspected PE. According to the nomogram, patients are segregated into low-risk (< 182 points) or high-risk (≥ 182 points) based on the best cut-off value to discard PE in the original cohort. We aimed to externally validate this diagnostic strategy in an independent cohort. We analyzed data from two retrospective cohorts of hospitalized non-critically ill COVID-19 patients who underwent a CTPA due to suspicion for PE. CHEDDAR score was applied. As per the CHEDDAR nomogram, patients were classified as having a low or high clinical pre-test probability. Of the 270 patients included, 69 (25.5%) had PE. Applying the CHEDDAR score, 182 (67.4%) patients could have had PE excluded without imaging. Among 58 patients classified as having high clinical pre-test probability, 39 (67.2%) had PE. Sensitivity, specificity, positive and negative predictive values, and AUC were 56%, 90%, 67%, 85%, and 0.783 (95% CI 0.71-0.85), respectively. We provide external validation of the CHEDDAR score in an independent cohort. Even though the CHEDDAR score showed good discrimination capacity, caution is required in patients classified as having low clinical pre-test probability with a D-dimer value > 3000 ng/mL, and a RALE score ≥ 4.

Obesity as a Predictor for Pulmonary Embolism and Performance of the Age-Adjusted D-Dimer Strategy in Obese Patients with Suspected Pulmonary Embolism

INTRODUCTION

 Obesity is a risk factor for venous thromboembolism, but studies evaluating its association with pulmonary embolism (PE) in patients with suspected PE are lacking.

OBJECTIVES

 To evaluate whether body mass index (BMI) and obesity (i.e., BMI ≥30 kg/m2) are associated with confirmed PE in patients with suspected PE and to assess the efficiency and safety of the age-adjusted D-dimer strategy in obese patients.

METHODS

 We conducted a secondary analysis of a multinational, prospective study, in which patients with suspected PE were managed according to the age-adjusted D-dimer strategy and followed for 3 months. Outcomes were objectively confirmed PE at initial presentation, and efficiency and failure rate of the diagnostic strategy. Associations between BMI and obesity, and PE were examined using a log-binomial model that was adjusted for clinical probability and hypoxia.

RESULTS

 We included 1,593 patients (median age: 59 years; 56% women; 22% obese). BMI and obesity were not associated with confirmed PE. The use of the age-adjusted instead of the conventional D-dimer cut-off increased the proportion of obese patients in whom PE was considered ruled out without imaging from 28 to 38%. The 3-month failure rate in obese patients who were left untreated based on a negative age-adjusted D-dimer cut-off test was 0.0% (95% confidence interval: 0.0-2.9%).

CONCLUSION

 BMI on a continuous linear scale and obesity were not predictors of confirmed PE among patients presenting with a clinical suspicion of PE. The age-adjusted D-dimer strategy appeared safe in ruling out PE in obese patients with suspected PE.

Pulmonary embolism risk stratification: external validation of the 4-level Clinical Pretest Probability Score (4PEPS)

Background

The 4-level clinical pretest probability score (4PEPS) was recently introduced as a clinical decision rule for the diagnosis of pulmonary embolism (PE). Based on the score, patients are classified into clinical pretest probability categories (c-PTP). The "very low" category aims at excluding PE without further testing; "low" and "moderate" categories require D-dimer testing with specific thresholds, while patients with a "high" pretest directly proceed to imaging.

Objectives

To provide further external validation of the 4PEPS model.

Methods

The 4PEPS was applied to a previously collected prospective database of 756 patients with clinically suspected PE enrolled from European emergency departments in 2002 to 2003. The safety threshold for the failure rate in our study was calculated at 1.95% based on a 26% prevalence of PE in our study, as per the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee guidance.

Results

Patients were classified as follows: 90 (12%) in the very low c-PTP group, of whom 5 (5.6%; 95% CI, 2.4%-12.4%) had PE; 363 (49%) in the low c-PTP group, of whom 34 had PE (9.4%); 246 (34%) in the moderate c-PTP group, of whom 124 (50%) had PE; and 35 (5%) in the high c-PTP group of whom 30 (86%) had PE. Overall, the failure rate of the 4PEPS was 9/734 (1.2%; 95% CI, 0.59%-2.23%) Overall, 9 out of 734 patients (1.2%; 95% CI, 0.59%-2.23%) were diagnosed with PE despite a negative 4PEPS rule; 5 (5.6%) from the very low c-PTP group, 3 (1.4%) in the low c-PTP group, and 1 (3.2%) in the moderate c-PTP group.

Conclusion

We provide external validation data of the 4PEPS. In this high-prevalence cohort (26% prevalence), PE prevalence in the very low-risk group was higher than expected. A prospective validation study is needed before implementing the 4PEPS model in routine clinical practice.

The Legend score synthesizes Wells, PERC, Geneva, D-dimer and predicts acute pulmonary embolism prior to imaging tests

INTRODUCTION

The prediction rules of acute pulmonary embolism(PE) before imaging tests recommended by the commonly used guidelines have low diagnostic efficiency if not combined with D-dimer, therefore it is necessary to seek for a prediction rule with higher diagnostic efficiency.

METHODS

We designed a new score named Legend by synthesizing the scores of Wells, PERC, and Geneva, as well as D-dimer with patients in the development group(n = 2112), and then validated it in patients of validation group(n = 388). Diagnostic efficiency was also compared between Legend score and Wells+D-dimer (DD), PERC+DD, Geneva+DD, and YEARS+DD(YEAR algorithm).

RESULTS

The Legend score comprised active cancer, D-dimer≥1000 ng/mL, DVT symptoms and/or signs, previous venous thromboembolism (VTE) history, and surgery, trauma, or immobilization in the past month. The sensitivity, specificity, Youden index, and area under the curve(AUC) were 0.985, 0.744, 0.729, and (0.861[0.796-0.925], P<0.001), respectively, for original Legend score, whereas were 0.982, 0.778, 0.760, and (0.871[0.823-0.920], P<0.001), respectively, for simplified Legend score. The Kappa coefficient and P value of McNemar test were 0.988 and 1.000, respectively, between the original and simplified Legend scores. In the validation group, the sensitivity, specificity, Youden index, and C-index were 0.971, 0.749, 0.720, and (0.838[0.781-0.896], P<0.001), respectively, for the original Legend score, whereas were 0.986, 0.715, 0.701, and (0.816[0.750-0.880], P = 0.001) respectively, for the simplified Legend score. The Kappa coefficient and P value of McNemar test between original Legend score and Wells+DD, PERC+DD, Geneva+DD, and YEARS+DD were (0.563, 0.001), (0.139, <0.001), (0.631, 0.006), and (0.732, 0.029), respectively. The Kappa coefficient and P value of McNemar test between simplified Legend score and aforementioned scores were (0.675, 0.009), (0.172, <0.001), (0.747, 0.001), and (0.883, 0.012), respectively.

DISCUSSION

In view of the fact the Legend score reserves the efficient predictors and eliminates the inefficient ones in Wells, PERC, and revised Geneva scores, and incorporates D-dimer into it, a more efficient, modified, and user-friendly one has replaced the original ones.

CONCLUSIONS

The Legend score yields excellent diagnostic efficiency with good safety in the pretest prediction of acute PE prior to imaging tests. It also avoids more unnecessary imaging tests than Wells+DD, PERC+DD, Geneva+DD, or YEARS+DD.

Performance of the 4-Level Pulmonary Embolism Clinical Probability Score (4PEPS) in the diagnostic management of pulmonary embolism: An external validation study

BACKGROUND

The recently published 4-level Pulmonary Embolism Clinical Probability Score (4PEPS) integrates different aspects from currently available diagnostic strategies to further reduce imaging testing in patients with clinically suspected pulmonary embolism (PE).

AIM

To externally validate the performance of 4PEPS in an independent cohort.

METHODS

In this post-hoc analysis of the prospective diagnostic management YEARS study, the primary outcome measures were discrimination, calibration, efficiency (proportion of imaging tests potentially avoided), and failure rate (venous thromboembolism (VTE) diagnosis at baseline or follow-up in patients with a negative 4PEPS algorithm). Multiple imputation was used for missing 4PEPS items. Based on 4PEPS, PE was considered ruled out in patients with a very low clinical pre-test probability (CPTP) without D-dimer testing, in patients with a low CPTP and D-dimer <1000 μg/L, and in patients with a moderate CPP and D-dimer below the age-adjusted threshold.

RESULTS

Of the 3465 patients, 474 (14 %) were diagnosed with VTE at baseline or during 3-month follow-up. Discriminatory performance of the 4PEPS items was good (area under ROC-curve, 0.82; 95%CI, 0.80-0.84) as was calibration. Based on 4PEPS, PE could be considered ruled out without imaging in 58 % (95%CI 57-60) of patients (efficiency), for an overall failure rate of 1.3 % (95%CI 0.86-1.9).

CONCLUSION

In this retrospective external validation, 4PEPS appeared to safely rule out PE with a high efficiency. Nevertheless, although not exceeding the failure rate margin by ISTH standards, the observed failure rate in our analysis appeared to be higher than in the original 4PEPS derivation and validation study. This highlights the importance of a prospective outcome study.

Pulmonary embolism diagnostic strategies in patients with COPD exacerbation: Post-hoc analysis of the PEP trial

BACKGROUND

The prevalence of pulmonary embolism (PE) is approximately 11-17 % in patients with an acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). The optimal diagnostic strategy for PE in these patients remains undetermined.

AIMS

To evaluate the safety and efficacy of standard (revised Geneva and Wells PE scores combined with fixed D-dimer cut-off) and computed tomography pulmonary angiogram (CTPA)-sparing diagnostic strategies (ADJUST-PE, YEARS, PEGeD, 4PEPS) in patients with AE-COPD.

METHOD

Post-hoc analyses of data from the multicenter prospective PEP study were performed. The primary outcome was the diagnostic failure rate of venous thromboembolism (VTE) during the entire study period. Secondary outcomes included diagnostic failure rate of PE and deep venous thrombosis (DVT), respectively, during the entire study period and the number of CTPA needed per diagnostic strategy.

RESULTS

740 patients were included. The revised Geneva and Wells PE scores combined with fixed D-dimer cut-off had a diagnostic failure rate of VTE of 0.7 % (95%CI 0.3 %-1.7 %), but >70.0 % of the patients needed imaging. All CTPA-sparing diagnostic algorithms reduced the need for CTPAs (-10.1 % to -32.4 %, depending on the algorithm), at the cost of an increased VTE diagnosis failure rate of up to 2.1 % (95%CI 1.2 %-3.4 %).

CONCLUSION

Revised Geneva and Wells PE scores combined with fixed D-dimer cut-off were safe, but a high number of CTPA remained needed. CTPA-sparing algorithms would reduce imaging, at the cost of an increased VTE diagnosis failure rate that exceeds the safety threshold. Further studies are needed to improve diagnostic management in this population.

Comparison of international guideline recommendations for the diagnosis of pulmonary embolism

Pulmonary embolism is one of the leading causes of death due to cardiovascular disease. Timely diagnosis is crucial, but challenging, as the clinical presentation of pulmonary embolism is unspecific and easily mistaken for other common medical emergencies. Clinical prediction rules and D-dimer measurement allow stratification of patients into groups of expected prevalence and are key elements in adequate selection of patients for diagnostic imaging; however, the strengths and weaknesses of the multiple proposed prediction rules, when to measure D-dimer, and which cutoff to apply might be elusive to a significant proportion of physicians. 13 international guidelines authored by medical societies or expert author groups provide recommendations on facets of the diagnostic investigations in suspected pulmonary embolism, some of which are hallmarked by pronounced heterogeneity. This Review summarises key recommendations of each guideline, considers the most recent evidence on the topic, compares guideline recommendations on each facet of the diagnosis of pulmonary embolism, and provides a synthesis on the most common recommendations.

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.

Diagnostic management of acute pulmonary embolism: a prediction model based on a patient data meta-analysis

AIMS

Risk stratification is used for decisions regarding need for imaging in patients with clinically suspected acute pulmonary embolism (PE). The aim was to develop a clinical prediction model that provides an individualized, accurate probability estimate for the presence of acute PE in patients with suspected disease based on readily available clinical items and D-dimer concentrations.

METHODS AND RESULTS

An individual patient data meta-analysis was performed based on sixteen cross-sectional or prospective studies with data from 28 305 adult patients with clinically suspected PE from various clinical settings, including primary care, emergency care, hospitalized and nursing home patients. A multilevel logistic regression model was built and validated including ten a priori defined objective candidate predictors to predict objectively confirmed PE at baseline or venous thromboembolism (VTE) during follow-up of 30 to 90 days. Multiple imputation was used for missing data. Backward elimination was performed with a P-value <0.10. Discrimination (c-statistic with 95% confidence intervals [CI] and prediction intervals [PI]) and calibration (outcome:expected [O:E] ratio and calibration plot) were evaluated based on internal-external cross-validation. The accuracy of the model was subsequently compared with algorithms based on the Wells score and D-dimer testing. The final model included age (in years), sex, previous VTE, recent surgery or immobilization, haemoptysis, cancer, clinical signs of deep vein thrombosis, inpatient status, D-dimer (in µg/L), and an interaction term between age and D-dimer. The pooled c-statistic was 0.87 (95% CI, 0.85-0.89; 95% PI, 0.77-0.93) and overall calibration was very good (pooled O:E ratio, 0.99; 95% CI, 0.87-1.14; 95% PI, 0.55-1.79). The model slightly overestimated VTE probability in the lower range of estimated probabilities. Discrimination of the current model in the validation data sets was better than that of the Wells score combined with a D-dimer threshold based on age (c-statistic 0.73; 95% CI, 0.70-0.75) or structured clinical pretest probability (c-statistic 0.79; 95% CI, 0.76-0.81).

CONCLUSION

The present model provides an absolute, individualized probability of PE presence in a broad population of patients with suspected PE, with very good discrimination and calibration. Its clinical utility needs to be evaluated in a prospective management or impact study.

REGISTRATION

PROSPERO ID 89366.

Strategies to safely rule out pulmonary embolism in COVID-19 outpatients: a multicenter retrospective study

OBJECTIVES

The objective was to define a safe strategy to exclude pulmonary embolism (PE) in COVID-19 outpatients, without performing CT pulmonary angiogram (CTPA).

METHODS

COVID-19 outpatients from 15 university hospitals who underwent a CTPA were retrospectively evaluated. D-Dimers, variables of the revised Geneva and Wells scores, as well as laboratory findings and clinical characteristics related to COVID-19 pneumonia, were collected. CTPA reports were reviewed for the presence of PE and the extent of COVID-19 disease. PE rule-out strategies were based solely on D-Dimer tests using different thresholds, the revised Geneva and Wells scores, and a COVID-19 PE prediction model built on our dataset were compared. The area under the receiver operating characteristics curve (AUC), failure rate, and efficiency were calculated.

RESULTS

In total, 1369 patients were included of whom 124 were PE positive (9.1%). Failure rate and efficiency of D-Dimer > 500 µg/l were 0.9% (95%CI, 0.2-4.8%) and 10.1% (8.5-11.9%), respectively, increasing to 1.0% (0.2-5.3%) and 16.4% (14.4-18.7%), respectively, for an age-adjusted D-Dimer level. D-dimer > 1000 µg/l led to an unacceptable failure rate to 8.1% (4.4-14.5%). The best performances of the revised Geneva and Wells scores were obtained using the age-adjusted D-Dimer level. They had the same failure rate of 1.0% (0.2-5.3%) for efficiency of 16.8% (14.7-19.1%), and 16.9% (14.8-19.2%) respectively. The developed COVID-19 PE prediction model had an AUC of 0.609 (0.594-0.623) with an efficiency of 20.5% (18.4-22.8%) when its failure was set to 0.8%.

CONCLUSIONS

The strategy to safely exclude PE in COVID-19 outpatients should not differ from that used in non-COVID-19 patients. The added value of the COVID-19 PE prediction model is minor.

KEY POINTS

• D-dimer level remains the most important predictor of pulmonary embolism in COVID-19 patients. • The AUCs of the revised Geneva and Wells scores using an age-adjusted D-dimer threshold were 0.587 (95%CI, 0.572 to 0.603) and 0.588 (95%CI, 0.572 to 0.603). • The AUC of COVID-19-specific strategy to rule out pulmonary embolism ranged from 0.513 (95%CI: 0.503 to 0.522) to 0.609 (95%CI: 0.594 to 0.623).

How to Combat Over-Testing for Patients Suspected of Pulmonary Embolism: A Narrative Review

The diagnosis of PE remains difficult in 2023 because the signs and symptoms are not sensible nor specific. The consequences of potential diagnostic errors can be dramatic, whether by default or by excess. Furthermore, the achievement of a simple diagnostic strategy, based on clinical probability assessment, D-dimer measurement and computed tomography pulmonary angiography (CTPA) leads to a new challenge for PE diagnosis: over-testing. Indeed, since the 2000s, the wide availability of CTPA resulted in a major increase in investigations with a mod I confirm erate increase in PE diagnosis, without any notable improvement in patient outcomes. Quite the contrary, the complications of anticoagulation for PE increased significantly, and the long-term consequences of imaging diagnostic radiation is an important concern, especially the risk of breast cancer for young women. As a result, several strategies have been proposed to fight over-testing. They are mostly based on defining a subgroup of patients for whom no specific exam should be required to rule-out PE and adjusting the D-dimer cutoff to allow the exclusion of PE without performing CTPA. This narrative review presents the advantages and limitations of these different strategies as well as the perspective in PE diagnosis.

Noninvasive diagnostic work-up for suspected acute pulmonary embolism during pregnancy: a systematic review and meta-analysis of individual patient data

BACKGROUND

Few studies evaluated the performance of noninvasive diagnostic strategies for suspected acute pulmonary embolism (PE) in pregnant women.

OBJECTIVES

The aim of this study was to establish the safety and efficiency of the Wells rule with fixed and adapted D-dimer threshold, and the YEARS algorithm, combined with compression ultrasonography (CUS), in pregnant women with suspected PE in an individual patient data meta-analysis.

METHODS

We performed a systematic review to identify prospective diagnostic management studies in pregnant women with suspected PE. Primary outcomes were safety, defined as the failure rate, ie, the 3-month venous thromboembolism (VTE) incidence after excluding PE without chest imaging, and efficiency, defined as the proportion of patients in whom chest imaging could be avoided.

RESULTS

We identified 2 relevant studies, of which individual patient-level data were analyzed in a fixed-effect meta-analysis, totaling 893 pregnant women. The Wells rule with fixed and adapted D-dimer threshold as well as the YEARS algorithm could safely rule out acute PE (failure rate, 0·37%-1·4%), but efficiency improved considerably when applying pretest probability-adapted D-dimer thresholds. The efficiency of bilateral CUS was limited (2·3% overall; number needed to test 43), especially in patients without symptoms of deep-vein thrombosis (efficiency 0·79%; number needed to test 127).

CONCLUSION

This study supports the latest guideline recommendations (European Society of Cardiology 2019) to apply pretest probability assessment and D-dimer tests to rule out PE in pregnant women. From an efficiency perspective, the use of a strategy with pretest probability-adapted D-dimer threshold is preferred. The yield of CUS was very limited in patients without concomitant symptoms of deep-vein thrombosis.

Systematic screening versus clinical gestalt in the diagnosis of pulmonary embolism in COVID-19 patients in the emergency department

BACKGROUND

Diagnosing concomitant pulmonary embolism (PE) in COVID-19 patients remains challenging. As such, PE may be overlooked. We compared the diagnostic yield of systematic PE-screening based on the YEARS-algorithm to PE-screening based on clinical gestalt in emergency department (ED) patients with COVID-19.

METHODS

We included all ED patients who were admitted because of COVID-19 between March 2020 and February 2021. Patients already receiving anticoagulant treatment were excluded. Up to April 7, 2020, the decision to perform CT-pulmonary angiography (CTPA) was based on physician's clinical gestalt (clinical gestalt cohort). From April 7 onwards, systematic PE-screening was performed by CTPA if D-dimer level was ≥1000 ug/L, or ≥500 ug/L in case of ≥1 YEARS-item (systematic screening cohort).

RESULTS

1095 ED patients with COVID-19 were admitted. After applying exclusion criteria, 289 were included in the clinical gestalt and 574 in the systematic screening cohort. The number of PE diagnoses was significantly higher in the systematic screening cohort compared to the clinical gestalt cohort: 8.2% vs. 1.0% (3/289 vs. 47/574; p<0.001), even after adjustment for differences in patient characteristics (adjusted OR 8.45 (95%CI 2.61-27.42, p<0.001) for PE diagnosis). In multivariate analysis, D-dimer (OR 1.09 per 1000 μg/L increase, 95%CI 1.06-1.13, p<0.001) and CRP >100 mg/L (OR 2.78, 95%CI 1.37-5.66, p = 0.005) were independently associated with PE.

CONCLUSION

In ED patients with COVID-19, the number of PE diagnosis was significantly higher in the cohort that underwent systematic PE screening based on the YEARS-algorithm in comparison with the clinical gestalt cohort, with a number needed to test of 7.1 CTPAs to detect one PE.

Diagnostic Strategy for Suspected Pulmonary Embolism in Emergency Departments Based on the 4-Level Pulmonary Embolism Clinical Probability Score: Study Protocol of SPEED&PEPS Trial

Introduction: Several strategies have been devised to safely limit the use of thoracic imaging in patients suspected of pulmonary embolism (PE). However, they are based on different rules for clinical probability (CP) assessment, rendering their combination difficult. The four-level pulmonary embolism probability score (4PEPS) allows the combination of all other strategies using a single CP assessment. Methods and analysis: Pragmatic cluster-randomized trial in 20 EDs. Patients with suspected PE will be included and followed for 90 days (number of patients to be included: 2560, 1280 in each arm). Ten centers will be allocated to the control group where physicians will be free to do as they see fit but they will be given the recommendation to apply a validated strategy. Ten centers will be allocated to the interventional group where the physicians will be given the recommendation to apply the 4PEPS strategy. The primary objective will be to demonstrate that the application of the 4PEPS strategy by the emergency physicians, in comparison to current practices, (i) does not increase the risk of serious events related to diagnostic strategies and (ii) significantly reduces the use of thoracic imaging. Ethics and dissemination: The study will be submitted for approval to an institutional ethics review board for all participating centers. If successful, the SPEED&PEPS trial will have an important impact for patients suspected of PE limiting their irradiation and for public health in substantial savings in terms of the direct cost of diagnostic investigations and the indirect cost of hospitalizations due to waiting times or delayed harmful effects. Funding: This work is funded by a French Public Health grant (PREPS-N 2019). The funding source plays no role in the study design, data collection, analysis, interpretation or the writing of the manuscript. Trial registration: ongoing. Trial status: not started.

D-dimer Testing in Pulmonary Embolism with a Focus on Potential Pitfalls: A Narrative Review

D-dimer is a multifaceted biomarker of concomitant activation of coagulation and fibrinolysis, which is routinely used for ruling out pulmonary embolism (PE) and/or deep vein thrombosis (DVT) combined with a clinical pretest probability assessment. The intended use of the tests depends largely on the assay used, and local guidance should be applied. D-dimer testing may suffer from diagnostic errors occurring throughout the pre-analytical, analytical, and post-analytical phases of the testing process. This review aims to provide an overview of D-dimer testing and its value in diagnosing PE and discusses the variables that may impact the quality of its laboratory assessment.

Evaluation of the "hemoptysis" item in clinical decision rules for the diagnosis of pulmonary embolism in the emergency department

BACKGROUND

Hemoptysis is not common in pulmonary embolism (PE) and lacks specificity for its diagnosis. However, this item is present in different validated scores that estimate the clinical probability of PE. The relevance of this item in clinical decision rules (CDRs) is not clearly established.

OBJECTIVE

The aim of this study was to evaluate the impact of removing the "hemoptysis" item from the PERC, YEARS, and PEGeD CDR in patients with low clinical probability of PE.

DESIGN

This was a post hoc analysis of two European prospective cohorts, which included 2968 patients presenting to the ED with a low clinical probability of PE (PROPER and PERCEPIC) and a 3-month follow-up. The primary endpoint was the false-negative rate of a CDR score without the hemoptysis item. Secondary endpoints included the potential reduction of chest imaging if the item hemoptysis was to be removed and risk stratification of the Geneva and Wells scores without the hemoptysis item.

RESULTS

Of 2968 patients included (mean ± SD age 46 ± 18 years, 53% female), 87 patients (3%) had a PE diagnosed at 3 months. A total of 2908 were followed-up at 3 months and analyzed. Using the PERC rule with and without the hemoptysis item, there were 13 and 14 missed cases of PE, respectively (failure rate 0.45% [95% CI 0.25%-0.78%] and 0.48% [95% CI 0.27%-0.82%]). Using the YEARS strategy, there were 11 missed PE cases with or without the hemoptysis item (false-negative rate 0.57% [95% CI 0.30%-1.05%]). With the PERC and YEARS rule, removing the hemoptysis item would have led to a 1% reduction in chest imaging. The PEGeD strategy was not modified by the removal of the hemoptysis item.

CONCLUSIONS

The hemoptysis item could be safely removed from the PERC, YEARS, and PEGeD CDRs. However, there was no subsequent clinically relevant reduction of chest imaging.

Comparison of the safety and efficacy of YEARS, PEGeD, 4PEPS or the sole item "PE is the most likely diagnosis" strategies for the diagnosis of pulmonary embolism in the emergency department: post-hoc analysis of two European cohort studies

BACKGROUND

The optimal strategy for the diagnosis of pulmonary embolism (PE) in the emergency department (ED) remains debated. To reduce the need of imaging testing, several rules have been recently validated using an elevated D-dimer threshold.

OBJECTIVE

To validate the safety of different diagnostic strategies and compare the efficacy in terms of chest imaging testing.

DESIGN AND PATIENTS

Post-hoc analysis of individual data of 3330 adult patients without a high clinical probability of PE in the ED followed-up at 3 months in France and Spain (1916 from the PROPER cohort, 1414 from the MODIGLIANI cohort).

EXPOSURE

Four diagnostic strategies with an elevated D-dimer threshold if PE is unlikely. The YEARS combined with Pulmonary Embolism Rule-out Criteria (PERC) the pulmonary embolism graduated D-dimer (PEGeD) combined with PERC and the 4-level pulmonary embolism probability score (4PEPS) rules were assessed. A modified simplified (MODS) rule with a simplified YEARS reduced to the sole item of "Is PE the most likely diagnosis" combined with PERC was also tested.

OUTCOME MEASURE AND ANALYSIS

The primary outcome was the proportion of diagnosed PE or deep venous thrombosis at 3 months in patients in whom PE could have been excluded without chest imaging according to the tested strategy. The safety of a strategy was confirmed if the failure rate was less than 1.85%. The secondary outcome was the use of imaging testing according to each rule.

RESULTS

Among 3330 analyzed patients, 150 (4.5%) had a PE. The number of missed PEs were 25, 29, 30 and 26 for the PERC+YEARS, PERC+PEGeD, 4PEPS and MODS rules respectively, with a failure rate of 0.75% (95% CI 0.51% to 1.10%), 0.87% (0.61% to 1.25%), 0.90% (0.63% to 1.28%) and 0.78% (0.53% to 1.14%) respectively. There was no significant difference in the failure rate between rules. Except for a significant lower use of chest imaging for 4PEPS compared to YEARS (14.9% vs 16.3%, difference -1.4% [95%CI -2.1% to -0.8%]), there was no difference in the proportion of imaging testing.

CONCLUSION

In this post-hoc analysis of patients with suspicion of PE, YEARS and PEGeD combined with PERC, and 4PEPS were safe to exclude PE. The safety of the modified simplified MODS strategy was also confirmed. There was no significant difference of the failure rate between strategies.

Diagnostic accuracy of adropin as a preliminary test to exclude acute pulmonary embolism: a prospective study

Background

This study aims to investigate the diagnostic accuracy of adropin as a biomarker to exclude the diagnosis of acute pulmonary embolism (PE).

Methods

Patients admitted to the emergency department of a tertiary health centre between August 2019 and August 2020 and diagnosed with PE were included in this prospective cohort study. The amount of serum adropin was determined in patients with (PE) and compared with that of healthy volunteers. Receiver operating characteristic analysis was performed with the obtained data, and the area under the curve (AUC) with a 95% confidence interval was determined. The parameters of diagnostic accuracy for PE were determined.

Results

A total of 57 participants were included in the study (28 controls and 29 PE patients). The mean adropin level in the PE group was 187.33 ± 62.40 pg/ml, which was significantly lower than that in the control group (524.06 ± 421.68 pg/ml) (p < 0.001). When the optimal adropin cut-off value was 213.78 pg/ml, the likelihood ratio of the adropin test was 3.4, and the sensitivity of the adropin test at this value was 82% with specificity of 75% (95% CI; AUC: 0.821).

Conclusion

Our results suggest that adropin may be considered for further study as a candidate marker for the exclusion of the diagnosis of PE. However, more research is required to verify and support the generalizability of our study results.

Diagnosis of Pulmonary Embolism during Pregnancy

Although rare, pulmonary embolism (PE) remains one of the most common causes of severe maternal morbidity and mortality during pregnancy. Among pregnant women with suspected PE, the prevalence of confirmed disease is far lower than in the general population, reflecting the fear of missing the diagnosis and a low threshold to suspect PE in this setting. Two prospective management outcome trials have recently assessed two different diagnostic algorithms based on the assessment of clinical probability, D-dimer, venous compression ultrasonography of the lower limbs (CUS), and computed tomography pulmonary angiography (CTPA). Both demonstrated the safety of such strategies to exclude PE, with a very low failure rate defined as the rate of subsequent 3-month venous thromboembolism in women left untreated after a negative work-up. These studies were also the first to prospectively demonstrate the safety of negative D-dimer associated with a clinical prediction rule to exclude PE without any chest imaging. Pregnant women are known to be a subgroup at particularly high risk of inappropriate diagnostic management, so the implementation of such validated diagnostic strategies in clinical practice should represent a high priority goal.

COVID-19 pneumonia imaging follow-up: when and how? A proposition from ESTI and ESR

This document from the European Society of Thoracic Imaging (ESTI) and the European Society of Radiology (ESR) discusses the role of imaging in the long-term follow-up of COVID-19 patients, to define which patients may benefit from imaging, and what imaging modalities and protocols should be used. Insights into imaging features encountered on computed tomography (CT) scans and potential pitfalls are discussed and possible areas for future review and research are also included. KEY POINTS: • Post-COVID-19 pneumonia changes are mainly consistent with prior organizing pneumonia and are likely to disappear within 12 months of recovery from the acute infection in the majority of patients. • At present, with the longest series of follow-up examinations reported not exceeding 12 months, the development of persistent or progressive fibrosis in at least some individuals cannot yet be excluded. • Residual ground glass opacification may be associated with persisting bronchial dilatation and distortion, and might be termed "fibrotic-like changes" probably consistent with prior organizing pneumonia.

Adjusted D-dimer cutoff levels to rule out pulmonary embolism in patients hospitalized for COPD exacerbation: results from the SLICE trial

Background

For patients with suspected pulmonary embolism (PE), age- or clinically-adjusted D-dimer threshold level can be used to define a negative test that safely excludes PE and reduces the use of imaging. However, the utility of this approach in patients hospitalized for chronic obstructive pulmonary disease (COPD) exacerbation is undefined.

Methods

We ran an analysis of the patients hospitalized for COPD exacerbation and randomized to the intervention in the SLICE trial. Using the conventional strategy as the reference, we compared the proportion of patients with a negative D-dimer result, and the negative predictive value and sensitivity of three D-dimer threshold strategies for initial PE or subsequent diagnosis of venous thromboembolism (VTE): the age-adjusted strategy, the Wells-adjusted strategy, and the YEARS-adjusted strategy.

Results

We included 368 patients. Using a conventional threshold, 182 (49.5%) patients had negative D-dimer values, of whom 1 (0.6%) had PE (sensitivity, 94.1%). The use of an age-adjusted threshold increased the number of patients in whom PE could be excluded from 182 to 233 patients (63.3%), and the proportion of false-negative findings increased from 0.5% to 1.7% (sensitivity, 76.5%). With the use of the Wells or YEARS strategies, 64.4% and 71.5% had negative values, and the proportion of false-negative findings was 2.5% (sensitivity, 64.7%) and 2.7% (sensitivity, 58.8%), respectively.

Conclusions

In patients hospitalized for COPD exacerbation, compared with the conventional strategy, age- or clinically-adjusted strategies of D-dimer interpretation were associated with a larger proportion of patients in whom PE was ruled out with a higher failure rate.

Trial Registration

ClinicalTrials.gov number: NCT02238639.

Diagnostic de l’embolie pulmonaire dans le contexte de la grossesse

Les problématiques posées par la prise en charge de la femme enceinte suspecte d’embolie pulmonaire (EP) aux urgences sont multiples. Les modifications physiologiques au cours de la grossesse majorent les sollicitations médicales pour des tableaux de douleur thoracique, de dyspnée, de malaise… En parallèle, ces manifestations aux cours de la grossesse peuvent se confondre avec les éléments évocateurs d’une EP et interférer sur nos capacités d’appréciation de sa probabilité. Enfin, l’élévation physiologique des D-dimères et le taux d’imageries thoraciques non conclusives complexifient la démarche diagnostique. C’est pourtant dans le contexte de la grossesse qu’il est particulièrement souhaitable de ne pas manquer un diagnostic d’EP, tout en évitant d’exposer inutilement la patiente et son foetus à l’imagerie thoracique. Pour aider dans les prises de décision, deux stratégies ont été validées dans le contexte de la grossesse. La première repose sur le score de Genève, incluant la réalisation d’une échographie de compression proximale chez les patientes à probabilité forte ou ayant un D-dimère supérieur à 500 μg/L. La seconde repose sur l’algorithme YEARS, avec réalisation d’une échographie uniquement chez les patientes ayant des symptômes évocateurs d’une thrombose veineuse des membres inférieurs associée, puis un dosage des D-dimères avec un seuil à 500 ou 1 000 μg/L en fonction de la probabilité clinique. La fiabilité de ces deux stratégies a été démontrée. La première stratégie présente l’avantage de ne reposer que sur des données objectives, et la deuxième de reposer le seuil décisionnel à 1 000 μg/L chez les patientes n’ayant aucun des critères YEARS.

Pulmonary Thromboembolism in Patients After COVID-19: Predictive Indicators for Correct Diagnosis

Background: Infection caused by SARS-CoV-2 can lead to significant procoagulant events, sometimes involving life-threatening pulmonary thromboembolism (PE). Additional conditions complicating the diagnosis are the presence of risk factors for PE in almost all patients with COVID-19 and the overlap of clinical presentation between PE and COVID-19. Objectives: We conducted a single-center study at the Heart and Brain Hospital, Pleven, from December 2020 to February 2021. It included 27 consecutively hospitalized patients with recent pneumonia caused by COVID-19 and clinical presentations corresponding to PE. Methods: The cohort was divided into two groups with and without a definitive diagnosis of PE, proven by CT pulmoangiography. The aim was to find the indicators predicting the presence of PE in patients with acute or post-acute COVID-19 conditions. Results: Our results showed that some ECG criteria, including S-wave over 1.5 mm in leads I and aVL (P = 0.007), Q-wave in leads III and aVF (P = 0.020), and D-dimer as a quantitative variable (P = 0.025), were independent predictors of PE. The RV/LV diameter ratios ≥ 1.0 and right ventricular dysfunction showed a sensitivity (Se) of 62.5%, specificity (Sp) of 100%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 86.4% to verify the PE diagnosis. Besides, the D-dimer cutoff value of 1,032 ng/mL had an optimal Se of 87.5%, Sp of 57.9%, PPV of 46.7%, and NPV of 91.7% for PE diagnosis (P = 0.021). Conclusions: Against the background of acute and post-acute COVID-19 conditions, ECG and EchoCG criteria remain the PE predictors. We suggest that a higher D-dimer cutoff value be applied in COVID-19 and post-COVID-19 patients to confirm/dismiss PE diagnosis.

Safety and Efficiency of Diagnostic Strategies for Ruling Out Pulmonary Embolism in Clinically Relevant Patient Subgroups : A Systematic Review and Individual-Patient Data Meta-analysis

BACKGROUND

How diagnostic strategies for suspected pulmonary embolism (PE) perform in relevant patient subgroups defined by sex, age, cancer, and previous venous thromboembolism (VTE) is unknown.

PURPOSE

To evaluate the safety and efficiency of the Wells and revised Geneva scores combined with fixed and adapted D-dimer thresholds, as well as the YEARS algorithm, for ruling out acute PE in these subgroups.

DATA SOURCES

MEDLINE from 1 January 1995 until 1 January 2021.

STUDY SELECTION

16 studies assessing at least 1 diagnostic strategy.

DATA EXTRACTION

Individual-patient data from 20 553 patients.

DATA SYNTHESIS

Safety was defined as the diagnostic failure rate (the predicted 3-month VTE incidence after exclusion of PE without imaging at baseline). Efficiency was defined as the proportion of individuals classified by the strategy as "PE considered excluded" without imaging tests. Across all strategies, efficiency was highest in patients younger than 40 years (47% to 68%) and lowest in patients aged 80 years or older (6.0% to 23%) or patients with cancer (9.6% to 26%). However, efficiency improved considerably in these subgroups when pretest probability-dependent D-dimer thresholds were applied. Predicted failure rates were highest for strategies with adapted D-dimer thresholds, with failure rates varying between 2% and 4% in the predefined patient subgroups.

LIMITATIONS

Between-study differences in scoring predictor items and D-dimer assays, as well as the presence of differential verification bias, in particular for classifying fatal events and subsegmental PE cases, all of which may have led to an overestimation of the predicted failure rates of adapted D-dimer thresholds.

CONCLUSION

Overall, all strategies showed acceptable safety, with pretest probability-dependent D-dimer thresholds having not only the highest efficiency but also the highest predicted failure rate. From an efficiency perspective, this individual-patient data meta-analysis supports application of adapted D-dimer thresholds.

PRIMARY FUNDING SOURCE

Dutch Research Council. (PROSPERO: CRD42018089366).

What level of D-dimers can safely exclude pulmonary embolism in COVID-19 patients presenting to the emergency department?

OBJECTIVES

To identify which level of D-dimer would allow the safe exclusion of pulmonary embolism (PE) in COVID-19 patients presenting to the emergency department (ED).

METHODS

This retrospective study was conducted on the COVID database of Assistance Publique - Hôpitaux de Paris (AP-HP). COVID-19 patients who presented at the ED of AP-HP hospitals between March 1 and May 15, 2020, and had CTPA following D-dimer dosage within 48h of presentation were included. The D-dimer sensitivity, specificity, and positive and negative predictive values were calculated for different D-dimer thresholds, as well as the false-negative and failure rates, and the number of CTPAs potentially avoided.

RESULTS

A total of 781 patients (mean age 62.0 years, 53.8% men) with positive RT-PCR for SARS-Cov-2 were included and 60 of them (7.7%) had CTPA-confirmed PE. Their median D-dimer level was significantly higher than that of patients without PE (4,013 vs 1,198 ng·mL^-1, p < 0.001). Using 500 ng·mL^-1, or an age-adjusted cut-off for patients > 50 years, the sensitivity and the NPV were above 90%. With these thresholds, 17.1% and 31.5% of CTPAs could have been avoided, respectively. Four of the 178 patients who had a D-dimer below the age-adjusted cutoff had PE, leading to an acceptable failure rate of 2.2%. Using higher D-dimer cut-offs could have avoided more CTPAs, but would have lowered the sensitivity and increased the failure rate.

CONCLUSION

The same D-Dimer thresholds as those validated in non-COVID outpatients should be used to safely rule out PE.

KEY POINTS

• The median D-dimer level was significantly higher in COVID-19 patients with PE as compared to those without PE (4,013 ng·mL^-1 vs 1,198 ng·mL^-1 respectively, p < 0.001). • Using 500 ng·mL^-1, or an age-adjusted D-dimer cut-off to exclude pulmonary embolism, the sensitivity and negative predictive value were above 90%. • Higher cut-offs would lead to a reduction in the sensitivity below 85% and an increase in the failure rate, especially for patients under 50 years.

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.

Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism: A Randomized Clinical Trial

IMPORTANCE

Uncontrolled studies suggest that pulmonary embolism (PE) can be safely ruled out using the YEARS rule, a diagnostic strategy that uses varying D-dimer thresholds.

OBJECTIVE

To prospectively validate the safety of a strategy that combines the YEARS rule with the pulmonary embolism rule-out criteria (PERC) rule and an age-adjusted D-dimer threshold.

DESIGN, SETTINGS, AND PARTICIPANTS

A cluster-randomized, crossover, noninferiority trial in 18 emergency departments (EDs) in France and Spain. Patients (N = 1414) who had a low clinical risk of PE not excluded by the PERC rule or a subjective clinical intermediate risk of PE were included from October 2019 to June 2020, and followed up until October 2020.

INTERVENTIONS

Each center was randomized for the sequence of intervention periods. In the intervention period (726 patients), PE was excluded without chest imaging in patients with no YEARS criteria and a D-dimer level less than 1000 ng/mL and in patients with 1 or more YEARS criteria and a D-dimer level less than the age-adjusted threshold (500 ng/mL if age <50 years or age in years × 10 in patients ≥50 years). In the control period (688 patients), PE was excluded without chest imaging if the D-dimer level was less than the age-adjusted threshold.

MAIN OUTCOMES AND MEASURES

The primary end point was venous thromboembolism (VTE) at 3 months. The noninferiority margin was set at 1.35%. There were 8 secondary end points, including chest imaging, ED length of stay, hospital admission, nonindicated anticoagulation treatment, all-cause death, and all-cause readmission at 3 months.

RESULTS

Of the 1414 included patients (mean age, 55 years; 58% female), 1217 (86%) were analyzed in the per-protocol analysis. PE was diagnosed in the ED in 100 patients (7.1%). At 3 months, VTE was diagnosed in 1 patient in the intervention group (0.15% [95% CI, 0.0% to 0.86%]) vs 5 patients in the control group (0.80% [95% CI, 0.26% to 1.86%]) (adjusted difference, -0.64% [1-sided 97.5% CI, -∞ to 0.21%], within the noninferiority margin). Of the 6 analyzed secondary end points, only 2 showed a statistically significant difference in the intervention group compared with the control group: chest imaging (30.4% vs 40.0%; adjusted difference, -8.7% [95% CI, -13.8% to -3.5%]) and ED median length of stay (6 hours [IQR, 4 to 8 hours] vs 6 hours [IQR, 5 to 9 hours]; adjusted difference, -1.6 hours [95% CI, -2.3 to -0.9]).

CONCLUSIONS AND RELEVANCE

Among ED patients with suspected PE, the use of the YEARS rule combined with the age-adjusted D-dimer threshold in PERC-positive patients, compared with a conventional diagnostic strategy, did not result in an inferior rate of thromboembolic events.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04032769.

D-dimer to rule out venous thromboembolism during pregnancy: A systematic review and meta-analysis

BACKGROUND

The usefulness of D-dimer measurement to rule out venous thromboembolism (VTE) during pregnancy is debated.

OBJECTIVES

We performed a systematic review and meta-analysis to investigate the safety of D-dimer to rule out acute VTE in pregnant women with suspected pulmonary embolism and/or deep vein thrombosis.

METHODS

Two reviewers independently identified studies through PubMed and Embase until June 2021, week 1. We supplemented our search by manually reviewing reference lists of all retrieved articles, clinicalTrials.gov, and reference literature. Prospective or retrospective studies in which a formal diagnostic algorithm was used to evaluate the ability of D-dimer to rule out VTE during pregnancy were eligible.

RESULTS

We identified 665 references through systematic database and additional search strategies; 45 studies were retrieved in full, of which four were included, after applying exclusion criteria. Three studies were prospective, and one had a retrospective design. The 3-month thromboembolic rate in pregnant women left untreated after a negative D-dimer was 1/312 (0.32%; 95% CI, 0.06-1.83). The pooled estimate values were 99.5% for sensitivity (95% CI, 95.0-100.0; I², 0%) and 100% for negative predictive value (95% CI, 99.19-100.0; I², 0%). The prevalence of VTE and the yield of D-dimer were 7.4% (95% CI, 3.8-12; I², 83%) and 34.2% (95% CI, 15.9-55.23; I², 89%) respectively.

CONCLUSION

Our results suggest that D-dimer allows to safely rule out VTE in pregnant women with suspected VTE and a disease prevalence consistent with a low/intermediate or unlikely pretest probability.

Ruling out Pulmonary Embolism in Patients with (Suspected) COVID-19-A Prospective Cohort Study

Background  Diagnostic strategies for suspected pulmonary embolism (PE) have not been prospectively evaluated in COVID-19 patients.

Methods  Prospective, multicenter, outcome study in 707 patients with both (suspected) COVID-19 and suspected PE in 14 hospitals. Patients on chronic anticoagulant therapy were excluded. Informed consent was obtained by opt-out approach. Patients were managed by validated diagnostic strategies for suspected PE. We evaluated the safety (3-month failure rate) and efficiency (number of computed tomography pulmonary angiographies [CTPAs] avoided) of the applied strategies.

Results  Overall PE prevalence was 28%. YEARS was applied in 36%, Wells rule in 4.2%, and “CTPA only” in 52%; 7.4% was not tested because of hemodynamic or respiratory instability. Within YEARS, PE was considered excluded without CTPA in 29%, of which one patient developed nonfatal PE during follow-up (failure rate 1.4%, 95% CI 0.04–7.8). One-hundred seventeen patients (46%) managed according to YEARS had a negative CTPA, of whom 10 were diagnosed with nonfatal venous thromboembolism (VTE) during follow-up (failure rate 8.8%, 95% CI 4.3–16). In patients managed by CTPA only, 66% had an initial negative CTPA, of whom eight patients were diagnosed with a nonfatal VTE during follow-up (failure rate 3.6%, 95% CI 1.6–7.0).

Conclusion  Our results underline the applicability of YEARS in (suspected) COVID-19 patients with suspected PE. CTPA could be avoided in 29% of patients managed by YEARS, with a low failure rate. The failure rate after a negative CTPA, used as a sole test or within YEARS, was non-negligible and reflects the high thrombotic risk in these patients, warranting ongoing vigilance.

Venous thromboembolism

Venous thromboembolism, comprising both deep vein thrombosis and pulmonary embolism, is a chronic illness that affects nearly 10 million people every year worldwide. Strong provoking risk factors for venous thromboembolism include major surgery and active cancer, but most events are unprovoked. Diagnosis requires a sequential work-up that combines assessment of clinical pretest probability for venous thromboembolism using a clinical score (eg, Wells score), D-dimer testing, and imaging. Venous thromboembolism can be considered excluded in patients with both a non-high clinical pretest probability and normal D-dimer concentrations. When required, ultrasonography should be done for a suspected deep vein thrombosis and CT or ventilation-perfusion scintigraphy for a suspected pulmonary embolism. Direct oral anticoagulants (DOACs) are the first-line treatment for almost all patients with venous thromboembolism (including those with cancer). After completing 3-6 months of initial treatment, anticoagulation can be discontinued in patients with venous thromboembolism provoked by a major transient risk factor. Patients whose long-term risk of recurrent venous thromboembolism outweighs the long-term risk of major bleeding, such as those with active cancer or men with unprovoked venous thromboembolism, should receive indefinite anticoagulant treatment. Pharmacological venous thromboembolism prophylaxis is generally warranted in patients undergoing major orthopaedic or cancer surgery. Ongoing research is focused on improving diagnostic strategies for suspected deep vein thrombosis, comparing different DOACs, developing safer anticoagulants, and further individualising approaches for the prevention and management of venous thromboembolism.

Challenges in the diagnostic approach of suspected pulmonary embolism in COVID-19 patients

Accumulating studies on COVID-19 patients report high incidences of thrombotic complications, but guidance on the best diagnostic approach for suspected pulmonary embolism (PE) in COVID-19 patients is lacking. Diagnosing PE in these patients is challenging as signs and symptoms of PE and COVID-19 show wide overlap, D-dimer levels are often elevated in the absence of thrombosis and computed tomography pulmonary angiography (CTPA) may be unfeasible in the case of severe renal impairment and/or hemodynamic instability.This narrative review discusses available literature and guidelines on current diagnostic algorithms for suspected PE in special patient populations, in particular COVID-19. A special focus is on reviewing the literature aimed at identifying symptoms with a high suspicion for PE and on the diagnostic performance of diagnostic algorithms for suspected PE in the setting of COVID-19.Based on available literature, the index of suspicion for PE should be high in the case of unexplained abrupt worsening of respiratory status, typical symptoms of deep-vein thrombosis and/or acute unexplained right ventricular dysfunction. Despite the lack of prospective diagnostic management studies, we propose to adhere to current diagnostic algorithms applying assessment of pretest probability and D-dimer testing as available evidence suggests that these might be considered safe. Preferably, algorithms using adjusted D-dimer thresholds are recommended as it likely improves the yield of the clinical decision rule/D-dimer combination.

Systematic review and meta-analysis of outcomes in patients with suspected pulmonary embolism

Prompt evaluation and therapeutic intervention of suspected pulmonary embolism (PE) are of paramount importance for improvement in outcomes. We systematically reviewed outcomes in patients with suspected PE, including mortality, incidence of recurrent PE, major bleeding, intracranial hemorrhage, and postthrombotic sequelae. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. We included 22 studies with 15 865 patients. Among patients who were diagnosed with PE and discharged with anticoagulation, 3-month follow-up revealed that all-cause mortality was 5.69% (91/1599; 95% confidence interval [CI], 4.56-6.83), mortality from PE was 1.19% (19/1597; 95% CI, 0.66-1.72), recurrent venous thromboembolism (VTE) occurred in 1.38% (22/1597; 95% CI: 0.81-1.95), and major bleeding occurred in 0.90% (2/221%; 95% CI, 0-2.15). In patients with a low pretest probability (PTP) and negative D-dimer, 3-month follow-up revealed mortality from PE was 0% (0/808) and incidence of VTE was 0.37% (4/1094; 95% CI: 0.007-0.72). In patients with intermediate PTP and negative D-dimer, 3-month follow-up revealed that mortality from PE was 0% (0/2747) and incidence of VTE was 0.46% (14/3015; 95% CI: 0.22-0.71). In patients with high PTP and negative computed tomography (CT) scan, 3-month follow-up revealed mortality from PE was 0% (0/651) and incidence of VTE was 0.84% (11/1302; 95% CI: 0.35-1.34). We further summarize outcomes evaluated by various diagnostic tests and diagnostic pathways (ie, D-dimer followed by CT scan).

Identifying Patients with Low Risk of Acute Coronary Syndrome Without Troponin Testing: Validation of the HEAR Score

BACKGROUND

Current guidelines for patients with suspected acute myocardial infarction are mainly based on troponin testing, commonly requiring an emergency department visit. HEAR score (History, Electrocardiogram, Age, and Risk factors) is a risk stratification tool validated in Europe, deduced from the HEART score (History, Electrocardiogram, Age, Risk factors, and Troponin), already implemented in clinical practice. We aimed to validate the HEAR score to rule out an acute myocardial infarction without needing biomarker testing.

METHODS

Retrospective cohort study at 15 emergency departments between May 2016 and December 2017. All adult encounters evaluated for possible acute myocardial infarction with a physician-documented HEART score for health plan members of Kaiser Permanente Southern California were included. Patients with an ST-segment elevation myocardial infarction, those under hospice care, or with a "do not resuscitate" status were excluded. HEAR scores from 0-8 were calculated for each encounter and used to report 30-day acute myocardial infarction or all-cause mortality for each score.

RESULTS

There were 22,109 patient encounters included in the study. Overall, 30-day acute myocardial infarction or death occurred in 1.1% of patients. Among the 4106 patients (19%) with a HEAR score <2, 3 died and 2 experienced an acute myocardial infarction within 30 days (0.1%; 95% confidence interval, 0.1-0.3). Sensitivity and specificity were 97.9% and 18.8%, respectively.

CONCLUSIONS

A low HEAR score may accurately identify patients with a very low risk of 30-day acute myocardial infarction or death, representing a cohort of patients who might appropriately forego biomarker testing. Future research is warranted to assess the impact of implementing the HEAR score into routine clinical practice.

How I treat venous thromboembolism in pregnancy

One to 2 pregnant women in 1000 will experience venous thromboembolism (VTE) during pregnancy or postpartum. Pulmonary embolism (PE) is a leading cause of maternal mortality, and deep vein thrombosis leads to maternal morbidity, with postthrombotic syndrome potentially diminishing quality of life for a woman's lifetime. However, the evidence base for pregnancy-related VTE management remains weak. Evidence-based guideline recommendations are often extrapolated from nonpregnant women and thus weak or conditional, resulting in wide variation of practice. In women with suspected PE, the pregnancy-adapted YEARS algorithm is safe and efficient, rendering computed tomographic pulmonary angiography to rule out PE unnecessary in 39%. Low molecular weight heparin (LMWH) in therapeutic doses is the treatment of choice during pregnancy, and anticoagulation (LMWH or vitamin K antagonists [VKAs]) should be continued until 6 weeks after delivery, with a 3-month minimum total duration. LMWH or VKA use does not preclude breastfeeding. Postpartum, direct oral anticoagulants are an option if a woman does not breastfeed and long-term use is intended. Management of delivery, including type of analgesia, requires a multidisciplinary approach and depends on local preferences and patient-specific conditions. Several options are possible, including waiting for spontaneous delivery with temporary LMWH interruption. Prophylaxis for recurrent VTE prevention in subsequent pregnancies is indicated in most women with a history of VTE.

Advances in the Management of Acute Venous Thromboembolism and New Therapeutic Agents

Important advances in the understanding and management of venous thromboembolism (VTE) have enhanced our ability to diagnose, prevent, and treat VTE. In this narrative review, we discuss how recent advances in the understanding and management of VTE are changing practice, highlight ongoing unmet needs in VTE management, and outline how novel therapeutic targets with little or no influence on hemostasis may help address these unmet needs.

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

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

Diagnostic accuracy of four different D-dimer assays: A post-hoc analysis of the YEARS study

INTRODUCTION

For exclusion of pulmonary embolism (PE) clinical decision rules in combination with a D-dimer assay are applied. Currently available D-dimer assays are not standardized and it is unknown whether these differences have an impact on diagnostic management of suspected PE. Therefore, the aim is to explore differences between D-dimer assays and their impact on diagnostic outcome.

METHODS

Data from all patients included in the YEARS study were collected. The YEARS study is a prospective, multicentre, cohort outcome study evaluating 3462 patients with suspected PE in which four different D-dimer assays were applied (Liatest, Innovance, Tinaquant, Vidas). Median D-dimer concentrations were calculated for each D-dimer assay. Sensitivity, specificity, PPV and NPV for detection of PE of all four assays were determined in patients without YEARS items and in those with ≥1 YEARS items (i.e. symptomatic deep vein thrombosis, haemoptysis, and whether PE is the most likely diagnosis).

RESULTS

A total of 1323, 1100, 768 and 271 D-dimer concentrations were collected using the Liatest Innovance, Tinaquant and Vidas assay, respectively. Median D-dimer concentrations differed significantly between assays, with lowest values in the Tinaquant assay. In patients without YEARS items using a cutoff level of 1000 ng/mL, the NPV varied from 99,5 to 100%. In patients with ≥1 YEARS items using a 500 ng/mL cutoff, the NPV varied from 97,0 to 100% depending on the assay.

CONCLUSIONS

The overall high NPV for all assays demonstrates the clinical value of the D-dimer assay. However, these results confirm differences between D-dimer assays, which have an impact on follow-up imaging. This emphasizes the need for standardization of D-dimer assays.