When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found

Subsegmental Pulmonary Embolism

Subsegmental pulmonary embolism (SSPE) is increasingly diagnosed with the growing use and technological advancements of multidetector computed tomography pulmonary angiography. Its diagnosis is challenging, and some presumed SSPE may actually represent imaging artifacts. Indirect evidence and results from small observational studies suggest that SSPE may be more benign than more proximal pulmonary embolism, and may thus not always require treatment. Therefore, guidelines suggest to consider a management strategy without anticoagulation in selected patients with SSPE at low risk of recurrent venous thromboembolism (VTE), in whom proximal deep vein thrombosis is excluded. Recently, a large prospective study among low-risk patients with SSPE who were left untreated showed a higher VTE recurrence risk than initially deemed acceptable by the investigators, and thus was prematurely interrupted after recruitment of 97% of the target population. However, the risk-benefit ratio of anticoagulation for low-risk patients with SSPE remains unclear, and results from randomized trials are needed to answer the question about their optimal management.

Epidemiology, Etiology, and Pathophysiology of Pulmonary Embolism

Over the last 20 years, there has been a progressive increase in the incidence of pulmonary embolism (PE) diagnosis in the United States, Europe, and Australia. Increased use of computed tomography pulmonary angiography has likely contributed in part to this rising incidence. However, it is pertinent to note that the burden of comorbidities associated with PE, such as malignancy, obesity, and advanced age, has also increased over the past 20 years. Time-trend analysis in North American, European, and Asian populations suggests that mortality rates associated with PE have been declining. The reported improved survival rates in PE over the past 20 years are likely, at least in part, to be the result of better adherence to guidelines, improved risk stratification, and enhanced treatment. Factors contributing to the development of venous thromboembolism (VTE) include stasis of blood, hypercoagulability, endothelial injury, and inflammation. In 70 to 80% of cases of PE, the thrombi embolizes from the proximal deep veins of the lower extremities and pelvis. Strong risk factors for VTE include lower extremity fractures and surgeries, major trauma, and hospitalization within the previous 3 months for acute myocardial infarction or heart failure with atrial fibrillation. Acute PE causes several pathophysiological responses including hypoxemia and right ventricle (RV) failure. The latter is a result of pulmonary artery occlusion and associated vasoconstriction. Hemodynamic compromise from RV failure is the principal cause of poor outcome in patients with acute PE.

Contemporary approaches to pulmonary embolism diagnosis: a clinical review

The optimal diagnosis strategy for pulmonary embolism (PE) in the emergency department (ED) remains complex. This review summarizes PE diagnosis with clinical presentation, decision rules and investigations for acute PE. This review was performed using studies published between January 1, 2010, and September 1, 2023. PE should be considered in ED in patients with chest pain, shortness of breath, syncope or signs of deep veinous thrombosis. Definitive diagnosis of PE relies on thoracic imaging, with the use of chest tomographic pulmonary angiogram or ventilation-perfusion lung scintigraphy. To limit the continuous increased use of chest imaging, the clinical probability should be the first step for PE workup. The pulmonary embolism rule-out criteria (PERC) can rule out PE at this stage. If not, for low or intermediate probability, several clinical decision rules have been validated, either by ruling out PE on clinical signs, or by raising D-dimer thresholds (YEARS or PEGeD [Pulmonary Embolism Graduated D-Dimer] criteria) or by combination of these different rules. It is recommended that patients with a high clinical probability of PE should undergo chest imaging without the need for D-dimer testing. The PE diagnostic approach can be tailored in specific populations such as pregnant, younger, COVID-19, or cancer patients. PE diagnosis workup illustrates the complexity of modern probabilistic-based approaches of decision-making in medicine. It is recommended to use a Bayesian approach with the evaluation of clinical probability, then order D-dimer if the PERC rule is positive, then adapt the D-dimer threshold for ordering chest imaging using clinical decision rules.

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.

The Harms of Unnecessary CT Pulmonary Angiography: A Case Report and Literature Review

Pulmonary embolism (PE) poses a significant health risk in the United States, with high mortality rates. Clinicians maintain a low threshold for suspecting PE, potentially leading to deviation from guideline-recommended algorithms and unnecessary computed tomography pulmonary angiography (CTPA). This case discusses a 46-year-old woman who presented with symptoms suggestive of PE following a prolonged road trip. Despite a low Wells score and negative D-dimer results, she underwent CTPA, resulting in an unnecessary and harmful interventional radiology-guided thrombectomy. This highlights the importance of adhering to guidelines in PE diagnosis to mitigate potential harms associated with the overuse of available medical tools.

Short- and Long-Term Mortality for Patients With and Without a Cancer Diagnosis Following Pulmonary Embolism in Denmark, 2000 to 2020: A Nationwide Study

BACKGROUND

New treatment regimens have been introduced in the past 20 years, which may influence the short- and long-term prognosis for patients with and without a cancer diagnosis following pulmonary embolism. However, newer studies investigating these trends are lacking. Therefore, we aimed to investigate the 30- and 31- to 365-day mortality following pulmonary embolism.

METHODS AND RESULTS

Using the Danish nationwide registries, patients with a diagnosis of pulmonary embolism between 2000 and 2020 were included. Age- and sex-standardized 30- and 31- to 365-day mortality was calculated and stratified by cancer status. In total, 60 614 patients (29.6% with recent cancer; mean age, 68.2 years) were included. The 30-day mortality for patients with no recent cancer decreased from 19.1% (95% CI, 17.9%-20.4%) in 2000 to 7.3% (95% CI, 6.7%-8.0%) in 2018 to 2020 (hazard ratio [HR], 0.36 [95% CI, 0.32-0.40]; P<0.001). The 30-day mortality for patients with recent cancer decreased from 32.2% (95% CI, 28.8%-36.6%) to 14.1% (95% CI, 12.7%-15.5%) (HR, 0.38 [95% CI, 0.33-0.44]; P<0.001). The 31- to 365-day mortality for patients with no recent cancer decreased from 12.5% (95% CI, 11.4%-13.6%) to 9.4% (95% CI, 8.6%-10.2%) (HR, 0.73 [95% CI, 0.64-0.83]; P<0.001).The 31- to 365-day mortality for patients with recent cancer remained stable: 39.4% (95% CI, 35.1%-43.7%) to 38.3% (95% CI, 35.9%-40.6%) (HR, 0.97 [95% CI, 0.84-1.12]; P=0.69).

CONCLUSIONS

From 2000 to 2020, improvements were observed in 30-day mortality following pulmonary embolism regardless of cancer status. For patients with recent cancer, 31- to 365-day mortality did not improve, whereas a minor improvement was observed for patients without recent cancer.

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.

Case Report: Two Case Reports of Pulmonary Hypertension after mRNA COVID-19 Vaccination

BACKGROUND

We herein report two cases of sudden onset symptomatic pulmonary hypertension after coronavirus disease 2019 (COVID-19) vaccination.

CASE SUMMARY

Pulmonary hypertension in previously healthy adult males occurred within three weeks of receiving the second dose of the Pfizer (BNT162b2) mRNA COVID-19 vaccine from different lots. Both patients experienced a sudden onset of severe fatigue and dyspnea on exertion with negative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) testing. The diagnosis was made by serial transthoracic echocardiography in the first case and by both transthoracic echocardiography and right heart catheterization in the second. Both cases resulted in functional limitations and likely permanent organ damage. No evidence of pulmonary emboli was detected in either case.

DISCUSSION

Pulmonary hypertension is a serious disease characterized by damage to lung vasculature and restricted blood flow through narrowed arteries from the right to left heart. The onset of symptoms is typically insidious, progressive and incurable, leading to right heart failure and premature death. The World Health Organization (WHO) classifies pulmonary hypertension into five categories and recently re-defined it as a resting mean pulmonary artery pressure greater than 20 mmHg. Sudden onset pulmonary hypertension would only be expected in the settings of surgical pneumonectomy or massive pulmonary emboli with compromise of at least 50% of the lung vasculature. We present here two novel cases of sudden onset pulmonary hypertension without evidence of pulmonary emboli, both of which occurred after receiving a COVID-19 mRNA vaccine.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Retrospective analysis.

SETTING

26 European EDs in 6 countries.

PATIENTS

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

MEASUREMENTS

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

RESULTS

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

LIMITATION

Data were limited to 7 days every 2 months.

CONCLUSION

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

PRIMARY FUNDING SOURCE

None specific for this study.

Assessment of the Utilization of Validated Diagnostic Predictive Tools and D-Dimer in the Evaluation of Pulmonary Embolism: A Single-Center Retrospective Cohort Study from a Public Hospital in New York City

INTRODUCTION

A significant increase in the use of computed tomography with pulmonary angiography (CTPA) for the diagnosis of pulmonary embolism (PE) has been observed in the past twenty years. We aimed to investigate whether the validated diagnostic predictive tools and D-dimers were adequately utilized in a large public hospital in New York City.

METHODS

We conducted a retrospective review of patients who underwent CTPA for the specific indication of ruling out PE over a period of one year. Two independent reviewers, blinded to each other and to the CTPA and D-dimer results, estimated the clinical probability (CP) of PE using Well's score, the YEARS algorithm, and the revised Geneva score. Patients were classified based on the presence or absence of PE in the CTPA.

RESULTS

A total of 917 patients were included in the analysis (median age: 57 years, female: 59%). The clinical probability of PE was considered low by both independent reviewers in 563 (61.4%), 487 (55%), and 184 (20.1%) patients based on Well's score, the YEARS algorithm, and the revised Geneva score, respectively. D-dimer testing was conducted in less than half of the patients who were deemed to have low CP for PE by both independent reviewers. Using a D-dimer cut-off of <500 ng/mL or the age-adjusted cut-off in patients with a low CP of PE would have missed only a small number of mainly subsegmental PE. All three tools, when combined with D-dimer < 500 ng/mL or <age-adjusted cut-off, yielded a NPV of > 95%.

CONCLUSION

All three validated diagnostic predictive tools were found to have significant diagnostic value in ruling out PE when combined with a D-dimer cut-off of <500 ng/mL or the age-adjusted cut-off. Excessive use of CTPA was likely secondary to suboptimal use of diagnostic predictive tools.

Clinical controversies in the management of acute pulmonary embolism: evaluation of four important but controversial aspects of acute pulmonary embolism management that are still subject of debate and research

INTRODUCTION

Acute pulmonary embolism (PE) is a disease with a broad spectrum of clinical presentations. While some patients can be treated at home or may even be left untreated, other patients require an aggressive approach with reperfusion treatment.

AREAS COVERED

(1) Advanced reperfusion treatment in hemodynamically stable acute PE patients considered to be at high risk of decompensation and death, (2) the treatment of subsegmental pulmonary embolism, (3) outpatient treatment for hemodynamically stable PE patients with signs of right ventricle (RV) dysfunction, and (4) the optimal approach to identify and treatpost-PE syndrome.

EXPERT OPINION

Outside clinical trials, hemodynamically stable acute PE patients should not be treated with primary reperfusion therapy. Thrombolysis and/or catheter-directed therapy are only to be considered as rescue treatment. Subsegmental PE can be left untreated in selected low-risk patients, after proximal deep vein thrombosis has been ruled out. Patients with an sPESI or Hestia score of 0 criteria can be treated at home, independent of the presence of RV overload. Finally, health-care providers should be aware of post-PE syndrome and diagnose chronic thromboembolic pulmonary disease (CTEPD) as early as possible. Persistently symptomatic patients without CTEPD benefit from exercise training and cardiopulmonary rehabilitation.

Incidental findings in medical imaging

The success of medical imaging as a diagnostic tool has resulted in a continuing increase in its use. Technological advances mean that images are now acquired at higher resolution and in greater volumes than ever before. This has led to an increase in the detection of findings which do not appear to be related to the primary purpose of the examination and have been termed "incidental". Many of these will be harmless but some will carry significant implications for the patient's health. Determining which of these findings are significant and which may be safely disregarded is an increasing problem in radiology practice. Radiologists should familiarise themselves with the more common incidental findings in order to make the best possible estimation of their importance in each case and to allow them to make appropriate recommendations for further investigation where this is indicated. The decision to advise further investigation carries implications for the patient and the service as a whole and requires careful consideration.

Diagnostic Accuracy of V/Q and Q SPECT/CT in Patients with Suspected Acute Pulmonary Embolism: A Systematic Review and Meta-analysis

BACKGROUND

 Computed tomography (CT) pulmonary angiography has simplified the diagnostic approach to patients with clinically suspected acute pulmonary embolism (PE), but alternative imaging tests are still advocated. We aimed to systematically assess the diagnostic accuracy of ventilation/perfusion (V/Q) and Q single-photon emission CT combined with low-dose CT (SPECT/CT) for PE diagnosis.

METHODS

 Studies evaluating the diagnostic accuracy of SPECT/CT for the diagnosis of acute PE were systematically searched in MEDLINE and EMBASE databases (up to August 2022). The QUADAS-2 tool was used for risk-of-bias assessment of the primary studies. A bivariate random-effects regression approach was used for summary estimates of both sensitivity and specificity. The PROSPERO registration number is CRD42021276538.

RESULTS

 Eight studies, for a total of 1,086 patients, were included. The risk of bias of all included studies was high. The weighted mean prevalence of PE was 27.1% at the random-effects model. The SPECT/CT bivariate weighted mean sensitivity was 96% (95% confidence interval [CI]: 93-98%), with a bivariate weighted mean specificity of 95% (95% CI: 90-97%). At subgroup analysis, for V/Q SPECT/CT bivariate weighted mean sensitivity and specificity were 96% (95% CI: 89-98%) and 96% (95% CI: 91-99%), while for Q SPECT/CT they were 96% (95% CI: 92-98%) and 84% (95% CI: 66-93%), respectively.

CONCLUSIONS

 V/Q SPECT/CT has high sensitivity and specificity for the diagnosis of acute PE, meanwhile Q SPECT/CT has high sensitivity but limited specificity for the diagnosis of PE. Management studies will conclusively ascertain the actual role of SPECT/CT in the diagnostic workup of patients with suspected acute PE.

Acute Pulmonary Embolism: A Review

IMPORTANCE

Pulmonary embolism (PE) is characterized by occlusion of blood flow in a pulmonary artery, typically due to a thrombus that travels from a vein in a lower limb. The incidence of PE is approximately 60 to 120 per 100 000 people per year. Approximately 60 000 to 100 000 patients die from PE each year in the US.

OBSERVATIONS

PE should be considered in patients presenting with acute chest pain, shortness of breath, or syncope. The diagnosis is determined by chest imaging. In patients with a systolic blood pressure of at least 90 mm Hg, the following 3 steps can be used to evaluate a patient with possible PE: assessment of the clinical probability of PE, D-dimer testing if indicated, and chest imaging if indicated. The clinical probability of PE can be assessed using a structured score or using clinical gestalt. In patients with a probability of PE that is less than 15%, the presence of 8 clinical characteristics (age <50 years, heart rate <100/min, an oxygen saturation level of > 94%, no recent surgery or trauma, no prior venous thromboembolism event, no hemoptysis, no unilateral leg swelling, and no estrogen use) identifies patients at very low risk of PE in whom no further testing is needed. In patients with low or intermediate clinical probability, a D-dimer level of less than 500 ng/mL is associated with a posttest probability of PE less than 1.85%. In these patients, PE can be excluded without chest imaging. A further refinement of D-dimer threshold is possible in patients aged 50 years and older, and in patients with a low likelihood of PE. Patients with a high probability of PE (ie, >40% probability) should undergo chest imaging, and D-dimer testing is not necessary. In patients with PE and a systolic blood pressure of 90 mm Hg or higher, compared with heparin combined with a vitamin K antagonist such as warfarin followed by warfarin alone, direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, are noninferior for treating PE and have a 0.6% lower rate of bleeding. In patients with PE and systolic blood pressure lower than 90 mm Hg, systemic thrombolysis is recommended and is associated with an 1.6% absolute reduction of mortality (from 3.9% to 2.3%).

CONCLUSIONS AND RELEVANCE

In the US, PE affects approximately 370 000 patients per year and may cause approximately 60 000 to 100 000 deaths per year. First-line therapy consists of direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, with thrombolysis reserved for patients with systolic blood pressure lower than 90 mm Hg.

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.

Peripheral Pulmonary Lesions in Confirmed Pulmonary Arterial Embolism: Follow-up Study of B-Mode Ultrasound and of Perfusion Patterns Using Contrast-Enhanced Ultrasound (CEUS)

PURPOSE

This retrospective study aimed to describe the B-mode lung ultrasound (B-LUS) and contrast-enhanced ultrasound (CEUS) follow-up patterns of peripheral pulmonary lesions (PPLs) in patients with confirmed pulmonary embolism (PE).

PATIENTS AND METHODS

Data from 27 patients with a confirmed diagnosis of PE and PPLs over 5 mm from October 2009 to November 2018 were included retrospectively in the study. The inclusion criteria were performance of a baseline CEUS examination, a short-term B-LUS and CEUS follow-up, and a long-term B-LUS follow-up of PPLs. The homogeneity of enhancement of PPLs (homogeneous/inhomogeneous/absent) on CEUS and the presence and size of PPLs on B-LUS were evaluated.

RESULTS

A total of n = 25/27 (92.6%) lesions showed absent or inhomogeneous enhancement during baseline examination or short-term follow-up, indicating impaired perfusion. On short-term CEUS follow-up, 9/27 cases (33.3%) showed a pattern shift. On B-LUS long-term follow-up, 26/27 lesions (96.3%) were detectable for an average of 10 weeks (range 3-32 weeks). The size of reference lesions was significantly reduced at the time of the final follow-up examination (P < .05).

CONCLUSION

B-LUS follow-up showed that, in patients with confirmed PE, PPLs had a delayed regression. On CEUS follow-up examination, various perfusion patterns of PPLs were observed, indicating the different ages and the variable reparative processes of pulmonary infarction. In PPLs independent of the underlying signs and symptoms, follow-up B-LUS and CEUS examinations may be helpful for a possible retrospective diagnosis of peripheral pulmonary infarction suggestive of PE.

Adherence to risk-assessment protocols to guide computed tomography pulmonary angiography in patients with suspected pulmonary embolism

AIMS

The use of computed tomography pulmonary angiography (CTPA) in the detection of pulmonary embolism (PE) has considerably increased due developing technology and better availability of imaging. The underuse of pre-test probability scores and overuse of CTPA has been previously reported. We sought to investigate the indications for CTPA at a University Hospital emergency clinic and seek for factors eliciting the potential overuse of CTPA.

METHODS AND RESULTS

Altogether 1001 patients were retrospectively collected and analysed from the medical records using a structured case report form. PE was diagnosed in 222/1001 (22.2%) of patients. Patients with PE had more often prior PE/deep vein thrombosis, bleeding/thrombotic diathesis and less often asthma, chronic obstructive pulmonary disease, coronary artery disease, or decompensated heart failure. Patients were divided into three groups based on Wells PE risk-stratification score and two groups based on the revised Geneva score. A total of 9/382 (2.4%), 166/527 (31.5%), and 47/92 (52.2%) patients had PE in the CTPA in the low, intermediate, and high pre-test likelihood groups according to Wells score, and 200/955 (20.9%) and 22/46 (47.8%) patients had PE in the CTPA in the low-intermediate and the high pre-test likelihood groups according to the revised Geneva score, respectively. D-dimer was only measured from 568/909 (62.5%) and 597/955 (62.5%) patients who were either in the low or the intermediate-risk group according to Wells score and the revised Geneva score. Noteworthy, 105/1001 (10.5%) and 107/1001 (10.7%) of the CTPAs were inappropriately ordered according to the Wells score and the revised Geneva score. Altogether 168/1001 (16.8%) could theoretically be avoided.

CONCLUSIONS

This study highlights scant utilization of guideline-recommended risk-stratification tools in CTPA use at the emergency department.

Pitfalls in the imaging of pulmonary embolism

Pulmonary embolism (PE) can present with a wide spectrum of clinical symptoms that can overlap considerably with other cardiovascular diseases. To avoid PE related morbidity and mortality, it is vital to identify this disease accurately and in a timely fashion. Several clinical criteria have been developed to standardize the diagnostic approach for patients with suspected PE. Computed tomographic pulmonary angiogram has significantly improved the detection of pulmonary embolism and is considered the imaging modality of choice to diagnose this disease. However, there are several potential pitfalls associated with this modality which can make diagnosis of PE challenging. In this review, we will discuss various pitfalls routinely encountered in the diagnostic work up of patients with suspected PE, approaches to mitigate these pitfalls and incidental pulmonary embolism.

A novel methodological framework was described for detecting and quantifying overdiagnosis

OBJECTIVES

Methods to quantify overdiagnosis of screen detected cancer have been developed, but methods for quantifying overdiagnosis of non-cancer conditions (whether symptomatic or asymptomatic) have been lacking. We aimed to develop a methodological framework for quantifying overdiagnosis that may be used for asymptomatic or symptomatic conditions, and used Gestational Diabetes Mellitus as an example of how it may be applied.

STUDY DESIGN AND SETTING

We identify two earlier definitions for overdiagnosis, a narrower prognosis-based definition, and a wider utility-based definition. Building on the central importance of the concepts of prognostic information and clinical utility of a diagnosis, we consider the following questions: within a target population, do people found to have a disease using one diagnostic strategy but found not to have the disease using another diagnostic strategy (so called 'additional diagnoses'), have an increased risk of adverse clinical outcomes without treatment (prognosis evidence), and/or a decreased risk of adverse outcomes with treatment (utility evidence)?

RESULTS

Using Causal Directed Acyclic Graphs and Fair Umpires, we illuminate the relationships between diagnostics strategies and the frequency of overdiagnosis. We then use the example of Gestational Diabetes Mellitus to demonstrate how the Fair Umpire framework may be applied to estimate overdiagnosis.

CONCLUSION

Our framework may be used to quantify overdiagnosis in non-cancer conditions (and in cancer conditions), as well as to guide further studies on this topic.

Evaluation of the Padua Prediction Score ability to predict venous thromboembolism in Israeli non-surgical hospitalized patients using electronic medical records

Venous thromboembolism (VTE) is considered a leading safety concern during hospitalization. The Padua Predication Score (PPS) is a risk model conceived to predict VTE among non-surgical hospitalized patients. The study aim was to evaluate the PPS ability to predict VTE in Israeli non-surgical hospitalized patients using data from electronic medical records. A single center, large-scale, historic cohort study of hospitalized non-surgical patients was conducted. Outcomes included clinically diagnosed symptomatic VTE events, bleeding events, and mortality during hospitalization and up to 90 days thereafter, and readmission up to 90 days after discharge. 5117 patient records were analyzed after screening and validation. 1120 (22%) patients were defined per PPS as high-risk, of which 277 (24.7%) were prophylactically treated. The low-risk group included 3997 (78%) patients. Prevalence of symptomatic VTE was low. Overall, 14 (0.27%) VTE events were diagnosed: 3 cases in the high-risk group (0.27%) and 11 (0.28%) in the low-risk group, with no significant difference, p = 0.768. Prophylactic treatment among the high-risk patients did not significantly improve VTE incidence: 1/277 (0.36%) treated vs. 2/843 (0.24%), p = 0.343. There was no significant difference between the study groups regarding the rates of bleeding, unexplained mortality or readmission. PPS was not found to be an efficient tool for identification of non-surgical hospitalized patients with high risk for clinically significant VTE.

Influence of using recommended radiological criteria on MDCT-angiography diagnosis of single isolated subsegmental pulmonary embolism

OBJECTIVES

We assessed the rate of false-positive diagnoses of MDCT-pulmonary angiography (MDCT-A) in patients with single isolated subsegmental pulmonary embolism (SISSPE).

METHODS

All patients who underwent MDCT-A between 2006 and 2017 for ruling out acute pulmonary embolism (PE) and received an initial diagnosis of SISSPE were included. The MDCT-A of these patients were reviewed retrospectively by four experienced thoracic radiologists, who applied radiological criteria recommended by the American College of Chest Physicians Antithrombotic Guidelines (ACCP 2016) for the diagnosis of SISSPE. Data extracted from medical records were history of venous thromboembolism (VTE), alternative diagnoses, other diagnostic studies for VTE, anticoagulation, bleeding complications, and VTE over the following 3 months.

RESULTS

Of 3839 patients undergoing MDCT-A, PE was found in 1021 (26.6%) and SISSPE in 59 (1.5% overall and 5.8% of all patients with PE). An alternative diagnosis to PE was made on the basis of CT in 33 (55.9%) patients. Forty-one (69.5%) patients received anticoagulants, and major life-threatening bleeding complications occurred in 2, with one death. Recurrent PE was not documented in any patient with SISSPE. In the retrospective assessment of the 59 cases of SISSPE, 21 were negative for PE, with a false-positive rate of 35.6% (21/59); so the percentage of SISSPE cases after the revision was 3.7% of all patients with PE; 11 of these 21 patients received anticoagulation.

CONCLUSIONS

Radiologists should be aware of the high rate of false-positives when making the diagnosis of SISSPE on MDCT-A without using strict diagnostic criteria. Misdiagnosis exposes patients to unnecessary anticoagulation.

KEY POINTS

• Radiologist should be aware of the high rate of false-positive diagnoses of single isolated subsegmental pulmonary embolism (SISSPE) in MDCT-pulmonary angiography (MDCT-A) performed for ruling out pulmonary embolism. • Misdiagnosis of SISSPE in MDCT-A can be reduced by using strict diagnostic radiological criteria recommended by the American College of Chest Physicians Antithrombotic Guidelines. • Unnecessary anticoagulation therapy with potential severe bleeding complications may result from misdiagnosis of SISSPE.

Diagnostic Stewardship: Appropriate Testing and Judicious Treatments

Diagnostic stewardship encompasses the entire diagnosis-to-treatment paradigm in the intensive care unit (ICU). Initially born of the antimicrobial stewardship movement, contemporary diagnostic stewardship aims to promote timely and appropriate diagnostic testing that directly links to management decisions. In the stewardship framework, excessive diagnostic testing in low probability cases is discouraged due to its tendency to generate false-positive results, which have their own downstream consequences. Though the evidence basis for diagnostic stewardship initiatives in the ICU is nascent and largely limited to retrospective analyses, available literature generally suggests that these initiatives are safe, feasible, and associated with similar patient outcomes. As diagnostic testing of critically ill patients becomes increasingly sophisticated in the ensuing decade, a stewardship mindset will aid bedside clinicians in interpreting and incorporating new diagnostic strategies in the ICU.

CT pulmonary angiography appropriateness in a single emergency department: does the use of revised Geneva score matter?

PURPOSE

To assess the percentage of computed tomography pulmonary angiography (CTPA) procedures that could have been avoided by methodical application of the Revised Geneva Score (RGS) coupled with age-adjusted D-dimer cut-offs rather than only clinical judgment in Emergency Department patients with suspected pulmonary embolism (PE).

MATERIAL AND METHODS

Between November 2019 and May 2020, 437 patients with suspected PE based on symptoms and D-dimer test were included in this study. All patients underwent to CTPA. For each patient, we retrospectively calculated the age-adjusted D-dimer cut-offs and the RGS in the original version. Finally, CT images were retrospectively reviewed, and the presence of PE was recorded.

RESULTS

In total, 43 (9.84%) CTPA could have been avoided by use of RGS coupled with age-adjusted D-dimer cut-offs. Prevalence of PE was 14.87%. From the analysis of 43 inappropriate CTPA, 24 (55.81%) of patients did not show any thoracic signs, two (4.65%) of patients had PE, and the remaining patients had alternative thoracic findings.

CONCLUSION

The study showed good prevalence of PE diagnoses in our department using only physician assessment, although 9.84% CTPA could have been avoided by methodical application of RGS coupled with age-adjusted D-dimer cut-offs.

Decision support for computed tomography in the emergency department: a multicenter cluster-randomized controlled trial

OBJECTIVES

Clinical decision support may facilitate evidence-based imaging, but most studies to date examining the impact of decision support have used non-randomized designs which limit the conclusions that can be drawn from them. This randomized trial examines if decision support can reduce computed tomography (CT) utilization for patients with mild traumatic brain injuries and suspected pulmonary embolism in the emergency department. This study was funded by a competitive public research grant and registered on ClinicalTrials.gov (NCT02410941).

METHODS

Emergency physicians at five urban sites were assigned to voluntary decision support for CT imaging of patients with either head injuries or suspected pulmonary embolism using a cluster-randomized design over a 1-year intervention period. The co-primary outcomes were CT head and CT pulmonary angiography utilization. CT pulmonary angiography diagnostic yield (proportion of studies diagnostic for acute pulmonary embolism) was a secondary outcome.

RESULTS

A total of 225 physicians were randomized and studied over a 2-year baseline and 1-year intervention period. Physicians interacted with the decision support in 38.0% and 45.0% of eligible head injury and suspected pulmonary embolism cases, respectively. A mixed effects logistic regression model demonstrated no significant impact of decision support on head CT utilization (OR 0.93, 95% CI 0.79-1.10, p = 0.31), CT pulmonary angiography utilization (OR 0.98, 95% CI 0.88-1.11, p = 0.74) or diagnostic yield (OR 1.23, 95% CI 0.96-1.65, p = 0.10). However, overall CT pulmonary diagnostic yield (17.7%) was almost three times higher than that reported by a recent large US study, suggesting that selective imaging was already being employed.

CONCLUSION

Voluntary decision support addressing many commonly cited barriers to evidence-based imaging did not significantly reduce CT utilization or improve diagnostic yield but was limited by low rates of participation and high baseline rates of selective imaging. Demonstrating value to clinicians through interventions that improve workflow is likely necessary to meaningfully change imaging practices.

Incidence of venous thromboembolism among patients with severe COVID-19 requiring mechanical ventilation compared to other causes of respiratory failure: a prospective cohort study

Previous studies have suggested that COVID-19 pneumonia is associated with an increased risk of venous thromboembolism (VTE). This study aimed to investigate the incidence of VTE among mechanically ventilated adults with COVID-19 pneumonia, compared to patients with respiratory failure related to other causes. Prospective study that enrolled critically ill adults with suspected COVID-19 pneumonia between June 2, 2020 and August 11, 2020. Critically ill adults with suspected COVID-19 pneumonia who required mechanical ventilation within 24 h after hospital admission were followed until death or hospital discharge. Sequential ultrasonography screening of the lower extremities and catheter insertion sites, as well as testing for plasma biochemical markers, were performed at the intensive care unit admission, day 3, day 7, and day 14. The primary outcome was a composite of deep venous thrombosis, pulmonary embolism, and thrombosis at the central catheter insertion sites. We enrolled 70 patients, including 57 patients with COVID-19 and 13 patients without COVID-19, and all patients completed follow-up. The incidence of the primary outcome was higher among patients with COVID-19 than among patients with respiratory failure related to other etiologies (36.8% vs. 0%, p = 0.023). Multivariate regression analysis revealed that VTE was independently associated with a COVID-19 diagnosis (odds ratio: 6.28, 95% confidence interval: 1.19–68.07) and D-dimer concentration (1-ng/mL increase, odds ratio: 1.15, 95% confidence interval: 1.05–1.30). The incidence of VTE was higher among critically ill mechanically ventilated patients, relative to among patients with respiratory failure related to other causes.

Trends in Imaging Findings, Interventions, and Outcomes Among Children With Isolated Head Trauma

OBJECTIVE

The aim was to analyze the impact of decreased head computed tomography (CT) imaging on detection of abnormalities and outcomes for children with isolated head trauma.

METHODS

The study involves a multicenter retrospective cohort of patients younger than 19 years presenting for isolated head trauma to emergency departments in the Pediatric Health Information System database from 2003 to 2015. Patients directly admitted or transferred to another facility and those with a discharge diagnosis code for child maltreatment were excluded. Outcomes were ascertained from administrative and billing data. Trends were tested using mixed effects logistic regression, accounting for clustering within hospitals and adjusted for age, sex, insurance type, race, presence of a complex chronic condition, and hospital-level case mix index.

RESULTS

Between 2003 and 2015, 306,041 children presented for isolated head trauma. The proportion of children receiving head CT imaging was increasing until 2008, peaking at just under 40%, before declining to 25% by 2015. During the recent period of decreased head CT imaging, the detection of skull fractures (odds ratio [OR]/year, 0.96; 95% confidence interval [CI], 0.95-0.97) and intracranial bleeds (OR/year, 0.96; 95% CI, 0.94-0.97), hospitalization (OR/year, 0.96; 95% CI, 0.95-0.96), neurosurgery (OR/year, 0.91; 95% CI, 0.87-0.95), and revisit (OR/year, 0.98; 95% CI, 0.96-1.00) also decreased, without significant changes in mortality (OR/year, 0.93; 95% CI, 0.84-1.04) or persistent neurologic impairment (OR/year, 1.03; 95% CI, 0.92-1.15).

CONCLUSIONS

The recent decline in CT scanning in children with isolated head trauma was associated with a reduction in detection of intracranial abnormalities, and a concomitant decrease in interventions, without measurable patient harm.

Symptomatic subsegmental versus more central pulmonary embolism: Clinical outcomes during anticoagulation

BACKGROUND

The optimal therapy of patients with acute subsegmental pulmonary embolism (PE) is controversial.

METHODS

We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to compare the rate of symptomatic PE recurrences during anticoagulation in patients with subsegmental, segmental, or more central PEs.

RESULTS

Among 15 963 patients with a first episode of symptomatic PE, 834 (5.2%) had subsegmental PE, 3797 (24%) segmental, and 11 332 (71%) more central PE. Most patients in all subgroups received initial therapy with low-molecular-weight heparin, and then most switched to vitamin K antagonists. Median duration of therapy was 179, 185, and 204 days, respectively. During anticoagulation, 183 patients developed PE recurrences, 131 developed deep vein thrombosis (DVT), 543 bled, and 1718 died (fatal PE, 135). The rate of PE recurrences was twofold higher in patients with subsegmental PE than in those with segmental (hazard ratio [HR], 2.13; 95% confidence interval [CI], 1.16-3.85) or more central PE (HR, 1.89; 95% CI, 1.12-3.13). On multivariable analysis, patients with subsegmental PE had a higher risk for PE recurrences than those with central PE (adjusted HR, 1.75; 95% CI, 1.02-3.03). After stratifying patients with subsegmental PE according to ultrasound imaging in the lower limbs, the rate of PE recurrences was similar in patients with DVT, in patients without DVT, and in those with no ultrasound imaging.

CONCLUSIONS

Our study reveals that the risk for PE recurrences in patients with segmental PE is not lower than in those with more central PE, thus suggesting that the risk of PE recurrences is not influenced by the anatomic location of PE.

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

IMPORTANCE

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

OBJECTIVE

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

DESIGN, SETTING, AND PARTICIPANTS

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

MAIN OUTCOMES AND MEASURES

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

RESULTS

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

CONCLUSIONS AND RELEVANCE

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

Syncope in pulmonary embolism: a retrospective cohort study

OBJECTIVE

To determine the prevalence of syncope or collapse in pulmonary embolism (PE).

METHODS

A retrospective cohort study was conducted. We examined the frequency with which syncope or collapse (presyncope) occurred alone or with other symptoms and signs in an unselected series of 224 patients presenting to a district general hospital with PE between September 2012 and March 2016. Confirmation of PE was by CT pulmonary angiogram in each case.

RESULTS

Our cohort of 224 patients comprised 97 men and 127 women, average age 66 years with age range of 21-94 years. Syncope or collapse was one of several symptoms and signs that led to a diagnosis of PE in 22 patients (9.8%) but was never the sole presenting feature. In descending order, these other clinical features were hypoxaemia (17 patients), dyspnoea (12), chest pain (9), tachycardia (7) and tachypnoea (7). ECG abnormalities reported to occur more commonly in PE were found in 13/17 patients for whom ECGs were available. Patients with PE presenting with syncope or collapse were judged to have a large clot load in 15/22 (68%) cases.

CONCLUSION

Syncope was a frequent presenting symptom in our study of 224 consecutive patients with PE but was never the sole clinical feature. It would be difficult to justify routine testing for PE in patients presenting only with syncope or collapse.

Investigation of pulmonary embolism in patients with chest pain in the emergency department: a retrospective multicenter study

INTRODUCTION

Chest pain is a common main complaint in the emergency department. Among its associated differential diagnoses, pulmonary embolism remains a key concern for the clinician. There are no clear recommendations on which patients should have a formal workup for pulmonary embolism diagnosis. The objective of this study was to determine the proportion of patients with chest pain who were investigated for pulmonary embolism diagnosis and to determine the clinical profile of these patients.

METHODS

This was a retrospective multicenter study conducted in three French Emergency Departments. We included all patients who presented to these centers for chest pain during a 2-month period. The primary outcome was the initiation of pulmonary embolism workup. We also aimed to find factors associated with this outcome.

RESULTS

We included 881 patients with a main complaint of chest pain. Mean age was 50 years and 481 (56%) were men. A total of 263 patients (30%, 95% confidence interval 27-33%) had a formal pulmonary embolism workup, and pulmonary embolism was ultimately diagnosed in 7 cases (prevalence of 2.6%, 95% confidence interval 1.1-5.3%). Five factors were identified as independently associated with a workup for pulmonary embolism diagnosis: female sex, young age, no ischemic heart disease, recent flight and associated dyspnea.

CONCLUSION

Among patients presenting to emergency department with chest pain, 30% had a workup for pulmonary embolism. We report five clinical variables independently associated with a higher probability of pulmonary embolism workup in our sample.

Overdiagnosis and overtreatment; how to deal with too much medicine

The past few decades have seen medical science making rapid strides in the field of diagnostic technologies, thus making it possible to detect some conditions at a very early stage. An unwanted effect of these developments is overdiagnosis which occurs when a true abnormality is discovered, but detection of that abnormality and its treatment does not benefit the patient. Overdiagnosis is encountered as a result cancer screening, in genetic diseases and in some chronic conditions when disease definition is broadened. There is urgent need of development of evidence based decision-making tools for clinicians which will help patients understand the benefits and harms of different screening and treatment methods. And the treating physician has to play a important role to convince the patient that watchful waiting, for some of the lesions may be the best option available in some circumstances.

How do patients and the public understand overtesting and overdiagnosis? A protocol for a thematic meta-synthesis of qualitative research

INTRODUCTION

Examining patient and public understanding of overtesting and overdiagnosis (OverTD) is vital for reducing the burden of OverTD. Studies from disparate contexts, disciplines and focusing on disparate healthcare issues have examined patient and public understanding of OverTD. A synthesis is needed to bring this literature together, examine common themes, strengthen conclusions and identify gaps. This will help steer further research, policy and practice to improve patient and public understanding of OverTD. The objective of this study is to synthesise qualitative research data about patient and public understanding of OverTD.

METHODS AND ANALYSIS

A thematic meta-synthesis will be used to synthesise primary qualitative research and qualitative components of primary mixed-methods research about patient and public understanding of OverTD. Studies published in English will be included. These will be identified using systematic searches from inception to March 2020 in the Scopus, CINAHL, PsycINFO and MEDLINE databases. Studies that satisfy eligibility criteria will be assessed for methodological quality using the Critical Appraisal Skills Programme (CASP) checklist. Thematic meta-synthesis will comprise three stages: (1) line-by-line coding; (2) generation of descriptive themes and (3) generation of analytic themes. Confidence in the synthesis findings will be assessed using the Grading of Recommendations Assessment, Development and Evaluation Confidence in Evidence (GRADE CERQual) approach. A summary of GRADE CERQual results will be presented alongside the key themes. Study eligibility screening, data extraction, analysis and the CASP and GRADE CERQual assessments will be undertaken independently by two review authors.

ETHICS AND DISSEMINATION

Ethics approval is not required for this secondary analysis of published data. The results will be disseminated in peer-reviewed journals and may be presented in conference papers and elsewhere.

PROSPERO REGISTRATION NUMBER

CRD42020156838.

Incidental pulmonary embolism in oncologic patients-a systematic review and meta-analysis

Purpose

Incidental pulmonary embolism (IPE) is a common finding on computed tomography (CT). IPE is frequent in oncologic patients undergoing staging CT. The aim of this analysis was to provide the pooled frequency of IPE and frequencies of IPE in different primary tumors.

Methods

MEDLINE, SCOPUS, and EMBASE databases were screened for studies investigating frequency of IPE in oncologic staging CT up to February 2020. Overall, 12 studies met the inclusion criteria and were included into the present study.

Results

The pooled analysis yielded a total of 28,626 patients. IPE was identified in 963 patients (3.36%, 95% CI = 3.15; 3.57). The highest frequency was found in prostate cancer (8.59%, 95%CI = 3.74; 13.44), followed by hepatobiliary carcinoma (6.07%, 95%CI = 3.09; 9.05) and pancreatic cancer (5.65%, 95%CI = 3.54; 7.76). The lowest frequencies were identified in tumors of male reproductive organs (0.79%, 95%CI = 0.21; 1.37) and hematological diseases (1.11% 95%CI = 0.74; 1.48).

Conclusion

The overall frequency of IPE in oncologic patients was 3.36%. There are considerable differences in regard to primary tumors with the highest frequency in prostate cancer and pancreatic and hepatobiliary carcinomas.

Risk of recurrent venous thromboembolism in patients with HIV infection: A nationwide cohort study

BACKGROUND

Multiple studies have described a higher incidence of venous thromboembolism (VTE) in people living with an HIV infection (PWH). However, data on the risk of recurrent VTE in this population are lacking, although this question is more important for clinical practice. This study aims to estimate the risk of recurrent VTE in PWH compared to controls and to identify risk factors for recurrence within this population.

METHODS AND FINDINGS

PWH with a first VTE were derived from the AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort (2003-2015), a nationwide ongoing cohort following up PWH in care in the Netherlands. Uninfected controls were derived from the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) follow-up study (1999-2003), a cohort of patients with a first VTE who initially participated in a case-control study in the Netherlands who were followed up for recurrent VTE. Selection was limited to persons with an index VTE suffering from deep vein thrombosis in the lower limbs and/or pulmonary embolism (PE). Participants were followed from withdrawal of anticoagulation to VTE recurrence, loss to follow-up, death, or end of study. We estimated incidence rates, cumulative incidence (accounting for competing risk of death) and hazard ratios (HRs) using Cox proportional hazards regression, adjusting for age, sex, and whether the index event was provoked or unprovoked. When analyzing risk factors among PWH, the main focus of analysis was the role of immune markers (cluster of differentiation 4 [CD4]+ T-cell count). There were 153 PWH (82% men, median 48 years) and 4,005 uninfected controls (45% men, median 49 years) with a first VTE (71% unprovoked in PWH, 34% unprovoked in controls) available for analysis. With 40 VTE recurrences during 774 person-years of follow-up (PYFU) in PWH and 635 VTE recurrences during 20,215 PYFU in controls, the incidence rates were 5.2 and 3.1 per 100 PYFU (HR: 1.70, 95% CI 1.23-2.36, p = 0.003). VTE consistently recurred more frequently per 100 PYFU in PWH in all predefined subgroups of men (5.6 versus 4.8), women (3.6 versus 1.9), and unprovoked (6.0 versus 5.2) or provoked (3.1 versus 2.1) first VTE. After adjustment, the VTE recurrence risk was higher in PWH compared to controls in the first year after anticoagulant discontinuation (HR: 1.67, 95% CI 1.04-2.70, p = 0.03) with higher cumulative incidences in PWH at 1 year (12.5% versus 5.6%) and 5 years (23.4% versus 15.3%) of follow-up. VTE recurred less frequently in PWH who were more immunodeficient at the first VTE, marked by a better CD4+ T-cell recovery on antiretroviral therapy and during anticoagulant therapy for the first VTE (adjusted HR: 0.81 per 100 cells/mm3 increase, 95% CI 0.67-0.97, p = 0.02). Sensitivity analyses addressing potential sources of bias confirmed our principal analyses. The main study limitations are that VTEs were adjudicated differently in the cohorts and that diagnostic practices changed during the 20-year study period.

CONCLUSIONS

Overall, the risk of recurrent VTE was elevated in PWH compared to controls. Among PWH, recurrence risk appeared to decrease with greater CD4+ T-cell recovery after a first VTE. This is relevant when deciding to (dis)continue anticoagulant therapy in PWH with otherwise unprovoked first VTE.

A systematic literature review and meta-analysis of spectral CT compared to scintigraphy in the diagnosis of acute and chronic pulmonary embolisms

PURPOSE

To examine the diagnostic accuracy of spectral CT pulmonary angiography (S-CTPA) using ventilation-perfusions lung scintigraphy (V/Q-scan) as a reference standard in the diagnosis of acute or chronic pulmonary embolism (APE/CPE) and chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

PubMed, Embase, Scopus, and Web of Science were searched for the period from 1 Jan 2006 to 7 Feb 2019; eligible studies had > 10 patients over 18 years old, a diagnostic outcome of PE or CTEPH, and used V/Q scan as a reference standard. Bias and applicability were assessed using QUADAS-2 tools. Sensitivities, specificities, and predictive values were noted or calculated from available information. Meta-analysis employed a fixed-effects model of Mantel and Haenszel. Heterogeneity was assessed with I-squared statistics.

RESULTS

Four hundred ninety-three unique records were identified. Following screening by title, 53 studies were included in the abstract and full-text assessment. A total of six articles were included; four were suitable for a meta-analysis. Pooled sensitivity was 94.2% (95% CI, 88.3-100%), pooled specificity was 88.5% (95% CI, 81.3-95.6%), and positive and negative predictive values were 87.8% (95% CI, 80.3-95.4%) and 94.5% (95% CI, 89.3-99.7%), respectively.

CONCLUSION

Data on S-CTPA for PE/CTEPH remains promising, but limited; only small studies with methodological issues are available. Evidence is best for CPE/CTEPH whereas no firm conclusions are possible for APE. There is a need for larger, prospective studies with a robust composite reference standard including state-of-the-art CTPA and V/Q-scans.

KEY POINTS

• S-CTPA has high sensitivity and specificity for perfusion defects in patients with PE or CPETH. • Methodological issues and diversity of reference standards were found in the small number of included studies. • There is a need for larger prospective studies with more robust composite reference standards.

Treatment and Outcomes of Acute Pulmonary Embolism and Deep Venous Thrombosis: The CVRN VTE Study

BACKGROUND

Few studies describe both inpatient and outpatient treatment and outcomes of patients with acute venous thromboembolism in the United States.

METHODS

A multi-institutional cohort of patients diagnosed with confirmed pulmonary embolism or deep venous thrombosis during the years 2004 through 2010 was established from 4 large, US-based integrated health care delivery systems. Computerized databases were accessed and medical records reviewed to collect information on patient demographics, clinical risk factors, initial antithrombotic treatment, and vital status. Multivariable Cox regression models were used to estimate the risk of death at 90 days.

RESULTS

The cohort comprised 5497 adults with acute venous thromboembolism. Pulmonary embolism was predominantly managed in the hospital setting (95.0%), while 54.5% of patients with lower extremity thrombosis were treated as outpatients. Anticoagulant treatment differed according to thromboembolism type: 2688 patients (92.8%) with pulmonary embolism and 1625 patients (86.9%) with lower extremity thrombosis were discharged on anticoagulants, compared with 286 patients (80.1%) with upper extremity thrombosis and 69 (54.8%) patients with other thrombosis. While 4.5% of patients died during the index episode, 15.4% died within 90 days. Pulmonary embolism was associated with a higher 90-day death risk than lower extremity thrombosis (adjusted hazard ratio 1.23; 95% confidence interval, 1.04-1.47), as was not being discharged on anticoagulants (adjusted hazard ratio 5.56; 95% confidence interval, 4.76-6.67).

CONCLUSIONS

In this multicenter, community-based study of patients with acute venous thromboembolism, anticoagulant treatment and outcomes varied by thromboembolism type. Although case fatality during the acute episode was relatively low, 15.4% of people with thromboembolism died within 90 days of the index diagnosis.