How I diagnose acute pulmonary embolism

The History of Diagnosing Venous Thromboembolism

An accurate and prompt diagnosis of deep vein thrombosis and/or pulmonary embolism is important to prevent serious complications and mortality. Because the clinical presentation of venous thromboembolism (VTE) is often nonspecific, objective testing by means of radiological imaging is required to confirm the diagnosis. Historically, a diagnosis of VTE involved invasive imaging techniques like contrast venography or conventional pulmonary angiography. Technological developments toward more accurate and less invasive diagnostics have driven the implementation of a variety of newer technologies over the past decades, as well as the derivation and validation of clinical decision rules (CDRs) that can be used to rule out VTE in combination with D-dimer blood tests. In this narrative review, we provide a historical overview of the most notable developments in the imaging techniques and CDRs for VTE diagnosis.

Reducing the global burden of cerebral venous thrombosis: An international research agenda

BACKGROUND

Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized.

AIMS

This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding.

SUMMARY OF REVIEW

This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion.

CONCLUSIONS

This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide.

Modern imaging of acute pulmonary embolism

The first-choice imaging test for visualization of thromboemboli in the pulmonary vasculature in patients with suspected acute pulmonary embolism (PE) is multidetector computed tomography pulmonary angiography (CTPA) - a readily available and widely used imaging technique. Through technological advancements over the past years, alternative imaging techniques for the diagnosis of PE have become available, whilst others are still under investigation. In particular, the evolution of artificial intelligence (AI) is expected to enable further innovation in diagnostic management of PE. In this narrative review, current CTPA techniques and the emerging technology photon-counting CT (PCCT), as well as other modern imaging techniques of acute PE are discussed, including CTPA with iodine maps based on subtraction or dual-energy acquisition, single-photon emission CT (SPECT), magnetic resonance angiography (MRA), and magnetic resonance direct thrombus imaging (MRDTI). Furthermore, potential applications of AI are discussed.

Diagnostic Management of Acute Pulmonary Embolism in COVID-19 and Other Special Patient Populations

Venous thromboembolism (VTE), in particular acute pulmonary embolism (PE), has been shown to be a frequent and potentially fatal complication of coronavirus disease 2019 (COVID-19). In response to the observed thrombotic complications, a large number of studies has been devoted to the understanding and management of COVID-19-associated coagulopathy. Notably, only a limited number of mostly retrospective studies has focused on the optimal diagnostic strategy for suspected PE in COVID-19 patients. As in other special populations, the accuracy of diagnostic algorithms for PE-exclusion has been debated in this specific patient subgroup as the specificity of D-dimer assays and clinical decision rules (CDRs) may be lower than normal. From this viewpoint, we discuss the current state-of-the-art diagnostic algorithms for acute PE with a focus on patients with COVID-19 in the perspective of other special patient populations. Furthermore, we summarize current knowledge regarding the natural history of PE resolution with anticoagulant treatment in patients with COVID-19.

Vascular imaging of the lung: perspectives on current imaging methods

This commentary will discuss the use of advanced non-invasive imaging methodology for the pulmonary vascular system with special attention to a rubric for the imaging and clinical team to use for any particular clinical situation.

Pulmonary Embolism and Chronic Superior Vena Cava Occlusion Complicating Central Line-Associated Venous Thromboembolism in a Sickle Cell Disease Patient

Sickle cell disease (SCD), the most common genetic disorder globally, is often associated with an increased risk of venous thromboembolic events (VTE). Many of these patients have central lines placed for the purposes of repeated medication administration, blood transfusions, and blood draw, further increasing the risk of VTE. Given the non-specific presentation of VTE and pulmonary embolism, as well as the risk of mortality if interventions are delayed, a high index of suspicion is required for early diagnosis of the condition. We report the case of a 35-year-old woman with SCD and a port-a-cath in place who presented with extensive upper extremity and intrathoracic VTE with associated pulmonary embolism and chronic superior vena cava (SVC) occlusion. We also discuss the peculiarities of the clinical manifestations and management of VTE and pulmonary embolism in the setting of SCD based on the evidence from existing literature.

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).

Identification of chronic thromboembolic pulmonary hypertension on CTPAs performed for diagnosing acute pulmonary embolism depending on level of expertise

BACKGROUND

Expert reading often reveals radiological signs of chronic thromboembolic pulmonary hypertension (CTEPH) or chronic PE on computed tomography pulmonary angiography (CTPA) performed at the time of acute pulmonary embolism (PE) presentation preceding CTEPH. Little is known about the accuracy and reproducibility of CTPA reading by radiologists in training in this setting.

OBJECTIVES

To evaluate 1) whether signs of CTEPH or chronic PE are routinely reported on CTPA for suspected PE; and 2) whether CTEPH-non-expert readers achieve comparable predictive accuracy to CTEPH-expert radiologists after dedicated instruction.

METHODS

Original reports of CTPAs demonstrating acute PE in 50 patients whom ultimately developed CTEPH, and those of 50 PE who did not, were screened for documented signs of CTEPH. All scans were re-assessed by three CTEPH-expert readers and two CTEPH-non-expert readers (blinded and independently) for predefined signs and overall presence of CTEPH.

RESULTS

Signs of chronic PE were mentioned in the original reports of 14/50 cases (28%), while CTEPH-expert radiologists had recognized 44/50 (88%). Using a standardized definition (≥3 predefined radiological signs), moderate-to-good agreement was reached between CTEPH-non-expert readers and the experts' consensus (k-statistics 0.46; 0.61) at slightly lower sensitivities. The CTEPH-non-expert readers had moderate agreement on the presence of CTEPH (κ-statistic 0.38), but both correctly identified most cases (80% and 88%, respectively).

CONCLUSIONS

Concomitant signs of CTEPH were poorly documented in daily practice, while most CTEPH patients were identified by CTEPH-non-expert readers after dedicated instruction. These findings underline the feasibility of achieving earlier CTEPH diagnosis by assessing CTPAs more attentively.

Efficacy and safety of a 12-week outpatient pulmonary rehabilitation program in Post-PE Syndrome

BACKGROUND

The Post-Pulmonary Embolism Syndrome (PPES) comprises heterogeneous entities, including chronic thromboembolic disease with/without pulmonary hypertension (CTEPH/CTEPD), and deconditioning.

OBJECTIVES

To assess underlying physiological determinants of PPES, and efficacy and safety of rehabilitation training in these patients.

METHODS

56 consecutive PE patients with persistent dyspnea and/or functional limitations despite ≥3 months of anticoagulation underwent standardized diagnostic work-up including exercise testing as part of routine practice. All diagnostic (imaging and cardiopulmonary function) tests were interpreted by a core group of experienced clinicians. A subgroup of patients without CTEPH or other treatable conditions was referred for a 12-week personalized rehabilitation program, studying changes in physical condition and patient-reported outcome measures.

RESULTS

Persistent vascular occlusions were observed in 21/56 patients (38%) and CTEPH was confirmed in ten (18%). Regarding those without CTEPH, impaired cardiopulmonary responses were evident in 18/39 patients with available CPET data (46%), unrelated to chronic thrombi. Rehabilitation was completed by 27 patients after excluding 29 (patients with CTEPH or treatable comorbidities, refusal, ineligibility, or training elsewhere). Training intensity, PE-specific quality of life (PEmb-QoL) and fatigue (CIS) improved with a median difference of 20 W (p = 0.001), 3.9 points (p < 0.001) and 16 points (p = 0.003), respectively. Functional status (Post-VTE Functional Status Scale) improved ≥1 grade in 18 (67%) patients, and declined in one (3.7%).

CONCLUSIONS

Our findings suggest that abnormal cardiopulmonary responses to exercise are common in patients with PPES and are not limited to those with chronic thrombi. Offering pulmonary rehabilitation to patients not treated otherwise seems safe and promising.

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.

Home Treatment Compared to Initial Hospitalization in Normotensive Patients with Acute Pulmonary Embolism in the Netherlands: A Cost Analysis

BACKGROUND

 Venous thromboembolism constitutes substantial health care costs amounting to approximately 60 million euros per year in the Netherlands. Compared with initial hospitalization, home treatment of pulmonary embolism (PE) is associated with a cost reduction. An accurate estimation of cost savings per patient treated at home is currently lacking.

AIM

 The aim of this study was to compare health care utilization and costs during the first 3 months after a PE diagnosis in patients who are treated at home versus those who are initially hospitalized.

METHODS

 Patient-level data of the YEARS cohort study, including 383 normotensive patients diagnosed with PE, were used to estimate the proportion of patients treated at home, mean hospitalization duration in those who were hospitalized, and rates of PE-related readmissions and complications. To correct for baseline differences within the two groups, regression analyses was performed. The primary outcome was the average total health care costs during a 3-month follow-up period for patients initially treated at home or in hospital.

RESULTS

 Mean hospitalization duration for the initial treatment was 0.69 days for those treated initially at home (n = 181) and 4.3 days for those initially treated in hospital (n = 202). Total average costs per hospitalized patient were €3,209 and €1,512 per patient treated at home. The adjusted mean difference was €1,483 (95% confidence interval: €1,181-1,784).

CONCLUSION

 Home treatment of hemodynamically stable patients with acute PE was associated with an estimated net cost reduction of €1,483 per patient. This difference underlines the advantage of triage-based home treatment of these patients.

Pulmonary infarction in acute pulmonary embolism

Pulmonary infarction results from occlusion of the distal pulmonary arteries leading to ischemia, hemorrhage and ultimately necrosis of the lung parenchyma. It is most commonly caused by acute pulmonary embolism (PE), with a reported incidence of around 30%. Following an occlusion of the pulmonary artery, the bronchial arteries are recruited as primary source of perfusion of the pulmonary capillaries. The relatively higher blood pressure in the bronchial circulation causes an increase in the capillary blood flow, leading to extravasation of erythrocytes (i.e. alveolar hemorrhage). If this hemorrhage cannot be resorbed, it results in tissue necrosis and infarction. Different definitions of pulmonary infarction are used in literature (clinical, radiological and histological), although the diagnosis is nowadays mostly based on radiological characteristics. Notably, the infarcted area is only replaced by a fibrotic scar over a period of months. Hence and formally, the diagnosis of pulmonary infarction cannot be confirmed upon diagnosis of acute PE. Little is known of the impact and relevance of pulmonary infarction in acute PE, and whether specific management strategies should be applied to prevent and/or treat complications such as pain, pneumonia or post-PE syndrome. In this review we will summarize current knowledge on the pathophysiology, epidemiology, diagnosis and prognosis of pulmonary infarction in the setting of acute PE. We highlight the need for dedicated studies to overcome the current knowledge gaps.

Incidence of thrombotic complications and overall survival in hospitalized patients with COVID-19 in the second and first wave

INTRODUCTION

In the first wave, thrombotic complications were common in COVID-19 patients. It is unknown whether state-of-the-art treatment has resulted in less thrombotic complications in the second wave.

METHODS

We assessed the incidence of thrombotic complications and overall mortality in COVID-19 patients admitted to eight Dutch hospitals between September 1st and November 30th 2020. Follow-up ended at discharge, transfer to another hospital, when they died, or on November 30th 2020, whichever came first. Cumulative incidences were estimated, adjusted for competing risk of death. These were compared to those observed in 579 patients admitted in the first wave, between February 24th and April 26th 2020, by means of Cox regression techniques adjusted for age, sex and weight.

RESULTS

In total 947 patients with COVID-19 were included in this analysis, of whom 358 patients were admitted to the ICU; 144 patients died (15%). The adjusted cumulative incidence of all thrombotic complications after 10, 20 and 30 days was 12% (95% confidence interval (CI) 9.8-15%), 16% (13-19%) and 21% (17-25%), respectively. Patient characteristics between the first and second wave were comparable. The adjusted hazard ratio (HR) for overall mortality in the second wave versus the first wave was 0.53 (95%CI 0.41-0.70). The adjusted HR for any thrombotic complication in the second versus the first wave was 0.89 (95%CI 0.65-1.2).

CONCLUSIONS

Mortality was reduced by 47% in the second wave, but the thrombotic complication rate remained high, and comparable to the first wave. Careful attention to provision of adequate thromboprophylaxis is invariably warranted.

Computed Tomography Pulmonary Perfusion for Prediction of Short-Term Clinical Outcome in Acute Pulmonary Embolism

Background  Computed tomography pulmonary angiography (CTPA) is the imaging modality of choice for the diagnosis of acute pulmonary embolism (PE). With computed tomography pulmonary perfusion (CTPP) additional information on lung perfusion can be assessed, but its value in PE risk stratification is unknown. We aimed to evaluate the correlation between CTPP-assessed perfusion defect score (PDS) and clinical presentation and its predictive value for adverse short-term outcome of acute PE.

Patients and Methods  This was an exploratory, observational study in 100 hemodynamically stable patients with CTPA-confirmed acute PE in whom CTPP was performed as part of routine clinical practice. We calculated the difference between the mean PDS in patients with versus without chest pain, dyspnea, and hemoptysis and 7-day adverse outcome. Multivariable logistic regression analysis and likelihood-ratio test were used to assess the added predictive value of PDS to CTPA parameters of right ventricle dysfunction and total thrombus load, for intensive care unit admission, reperfusion therapy and PE-related death.

Results  We found no correlation between PDS and clinical symptoms. PDS was correlated to reperfusion therapy ( n  = 4 with 16% higher PDS, 95% confidence interval [CI]: 3.5–28%) and PE-related mortality ( n  = 2 with 22% higher PDS, 95% CI: 4.9–38). Moreover, PDS had an added predictive value to CTPA assessment for PE-related mortality (from Chi-square 14 to 19, p  = 0.02).

Conclusion  CTPP-assessed PDS was not correlated to clinical presentation of acute PE. However, PDS was correlated to reperfusion therapy and PE-related mortality and had an added predictive value to CTPA-reading for PE-related mortality; this added value needs to be demonstrated in larger studies.

Establishing diagnostic criteria and treatment of subsegmental pulmonary embolism: A Delphi analysis of experts

Background

Improved imaging techniques have increased the incidence of subsegmental pulmonary embolism (ssPE). Indirect evidence is suggesting that ssPE may represent a more benign presentation of venous thromboembolism not necessarily requiring anticoagulant treatment. However, correctly diagnosing ssPE is challenging with reported low interobserver agreement, partly due to the lack of widely accepted diagnostic criteria.

Objectives

We sought to derive uniform diagnostic criteria for ssPE, guided by expert consensus.

Methods

Based on an extensive literature review and expert opinion of a Delphi steering committee, two surveys including statements regarding diagnostic criteria and management options for ssPE were established. These surveys were conducted electronically among two panels, respectively: expert thoracic radiologists and clinical venous thromboembolism specialists. The Delphi method was used to achieve consensus after multiple survey rounds. Consensus was defined as a level of agreement >70%.

Results

Twenty‐nine of 40 invited radiologists (73%) and 40 of 51 clinicians (78%) participated. Following two survey rounds by the expert radiologists, consensus was achieved on 15 of 16 statements, including on the established diagnostic criteria for ssPE (96% agreement): a contrast defect in a subsegmental artery, that is, the first arterial branch division of any segmental artery independent of artery diameter, visible in at least two subsequent axial slices, using a computed tomography scanner with a desired maximum collimator width of ≤1 mm. These criteria were approved by 83% of the clinical venous thromboembolism (VTE) specialists. The clinical expert panel favored anticoagulant treatment in case of prior VTE, antiphospholipid syndrome, pregnancy, cancer, and proximal deep vein thrombosis.

Conclusion

The results of this analysis provide standard radiological criteria for ssPE that may be applicable in both clinical trials and practice.

Lack of diagnostic utility of the ECG-derived ventricular gradient in patients with suspected acute pulmonary embolism

INTRODUCTION

The YEARS algorithm was successfully developed to reduce the number of computed tomography pulmonary angiography (CTPA) investigations in the diagnostic management of patients with suspected pulmonary embolism (PE), although half of patients still needed to be referred for CTPA. We hypothesized that ECG derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO), an easy to use tool for detecting PE-induced pulmonary hypertension (PH), may further improve the efficiency of the YEARS algorithm.

METHODS

In this post-hoc analysis of the Years study, ECGs of 479 patients with suspected PE managed according to the YEARS algorithm were available for analysis. The diagnostic performance of VG-RVPO was assessed and likelihood ratios were calculated.

RESULTS

PE was diagnosed in 88 patients (18%). In patients with confirmed PE, 34% had an abnormal VG-RVPO versus 24% of those without PE (odds ratio 1.6; 95%CI 0.94-2.6). The mean VG-RVPO was -22 ± 13 and did not differ between the two patient groups (-22 versus -20; mean difference - 2, 95% CI -4.8 to 1.3). The sensitivity of VG-RVPO for PE was 24% (95%CI 34-45), the specificity 76% (95%CI 71-80) and the c-statistic 0.45 (95% CI 0.38-0.51). When combined with the YEARS algorithm, the likelihood ratios of VG-RVPO remained close to 1.0. Ruling out PE in patients with an indication for CTPA based on a normal VG-RVPO would have resulted in 58 missed cases.

CONCLUSIONS

The VG-RVPO has no diagnostic value for suspected acute PE, either as stand-alone diagnostic test or combined with the YEARS algorithm.

CONDENSED ABSTRACT

This post-hoc analysis of the YEARS study failed to demonstrate incremental diagnostic value of VG-RVPO for acute PE, either as stand-alone diagnostic test or combined with the YEARS algorithm. Nevertheless, the role of VG-RVPO recorded on admission could potentially be valuable in the risk stratification of PE during hospitalization, although this remains to be studied.

Diagnosis of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is the most severe long-term complication of acute pulmonary embolism (PE). Untreated CTEPH is fatal, but, if diagnosed in time, successful surgical (pulmonary endarterectomy), medical (pulmonary hypertension drugs) and/or interventional (balloon pulmonary angioplasty) therapies have been shown to improve clinical outcomes, especially in case of successful pulmonary endarterectomy. Early diagnosis has however been demonstrated to be challenging. Poor awareness of the disease by patients and physicians, high prevalence of the post-PE syndrome (i.e. persistent dyspnoea, functional limitations and/or decreased quality of life following an acute PE diagnosis), lack of clear guideline recommendations as well as inefficient application of diagnostic tests in clinical practice lead to a reported staggering diagnostic delay >1 year. Hence, there is a great need to improve current clinical practice and diagnose CTEPH earlier. In this review, we will focus on the clinical presentation of and risk factors for CTEPH, and provide best practices for PE follow-up programmes from expert centres, based on a clinical case.

Acute and Chronic Respiratory Failure in Cancer Patients

In 2016, there was an estimated 1.8 million new cases of cancer diagnosed in the United States. Remarkable advances have been made in cancer therapy and the 5-year survival has increased for most patients affected by malignancy. There are growing numbers of patients admitted to intensive care units (ICU) and up to 20% of all patients admitted to an ICU carry a diagnosis of malignancy. Respiratory failure remains the most common reason for ICU admission and remains the leading causes of death in oncology patients. There are many causes of respiratory failure in this population. Pneumonia is the most common cause of respiratory failure, yet there are many causes of respiratory insufficiency unique to the cancer patient. These causes are often a result of immunosuppression, chemotherapy, radiation treatment, or hematopoietic stem cell transplant (HCT). Treatment is focused on supportive care and specific therapy for the underlying cause of respiratory failure. Noninvasive modalities of respiratory support are available; however, careful patient selection is paramount as indiscriminate use of noninvasive positive pressure ventilation is associated with a higher mortality if mechanical ventilation is later required. Historically, respiratory failure in the cancer patient had a grim prognosis. Outcomes have improved over the past 20 years. Survivors are often left with significant disability.

Chest X-Ray Not Routinely Indicated Prior to the YEARS Algorithm in the Diagnostic Management of Suspected Pulmonary Embolism

Background  The YEARS algorithm was designed to simplify the diagnostic process of suspected pulmonary embolism (PE) and to reduce the number of required computed tomography pulmonary angiography (CTPA) scans. Chest X-ray (CXR) is often used as initial imaging test in patients suspected for PE. Aim  To determine if CXR results differ between patients with confirmed PE and with PE ruled out, and to investigate whether CXR provides incremental diagnostic value to the YEARS criteria that is used for selecting patients with CTPA indication. Methods  This post-hoc analysis concerned 1,473 consecutive patients with suspected PE who were managed according to YEARS and were subjected to CXR as part of routine care. The prevalence and likelihood ratios of seven main CXR findings for a final diagnosis of PE were calculated. Results  A total of 214 patients were diagnosed with PE at baseline (15%). Abnormal CXR occurred more often in patients with confirmed PE (36%, 77/214) than in patients without PE (26%; 327/1,259), for an odds ratio of 1.60 (95% confidence interval: 1.18-2.18). Only the unexpected finding of a (rib)fracture or pneumothorax, present in as few as six patients (0.4%), significantly lowered the post-test probability of PE to an extent that CTPA could have been avoided. Conclusion  The incremental diagnostic value of CXR to the YEARS algorithm to rule out PE was limited. CXR was more frequently abnormal in patients with PE than in those in whom PE was ruled out. These data do not support to perform CXR routinely in all patients with suspected PE, prior to CTPA imaging.

The problem of under-diagnosis and over-diagnosis of pulmonary embolism

Pulmonary embolism (PE) is an increasingly recognised condition which is associated with significant morbidity and mortality. Despite the better awareness of this serious condition, the diagnosis is still overlooked in many cases with sometimes fatal consequences. Under-diagnosis may be due to several reasons including reliance on non-specific 'classic' symptoms, belief that bedside measurements will likely be abnormal in the setting of acute PE, and confounding factors like co-existent cardiorespiratory diseases or being in an intensive care unit, where the diagnosis may not be considered. At the same time, incidental diagnosis of PE is occurring more often due to frequent use of imaging investigations alongside advancements in CT technology, and dilemma exists as to whether the chance finding of PE requires anticoagulation, especially when identified only at the subsegmental level. This article reviews these two issues of under-diagnosis and over-diagnosis of PE in the current era.

May-Thurner syndrome and the risk of pulmonary embolism in patients with acute deep venous thrombosis

OBJECTIVE

Pulmonary embolism (PE) is the most common complication of deep venous thrombosis (DVT). May-Thurner syndrome (MTS) is known to increase the risk of DVT, but an association between MTS and PE has not been established. This study investigated an association between MTS and the risk of PE in patients with acute lower extremity DVT.

METHODS

Between June 2014 and September 2016, there were 112 patients with DVT at our hospital who underwent venous angiography and computed tomography pulmonary angiography. Data related to the patients' demographics, risk factors, disease onset time, side of DVT, D-dimer level, Doppler ultrasound, venous angiography, and computed tomography pulmonary angiography were collected. Associations between MTS and PE were analyzed.

RESULTS

The 112 DVT patients included 79 with MTS. The rate of DVT in the left lower extremity was higher in the MTS group (98.7%) than in the non-MTS group (48.5%; P < .001). PE was less common in the MTS group (50.6%) than in the non-MTS group (78.8%; P = .006). The multinomial logistic analysis revealed a significant negative correlation between MTS and PE. The correlation remained after applying adjustment models I, II, and III. Model I adjusted for risk factors, DVT side, and D-dimer tertile (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.04-0.68; P = .0125); model II adjusted for sex, age, risk factors, onset time, DVT side, D-dimer level, and D-dimer tertile (OR, 0.15; 95% CI, 0.03-0.71; P = .0162); and model III adjusted for sex, age, risk factors, onset time, DVT side, D-dimer level, D-dimer tertile, iliofemoral DVT, mixed (both iliofemoral and femoropopliteal) DVT, and femoropopliteal DVT (OR, 0.35; 95% CI, 0.06-2.08; P = .2501).

CONCLUSIONS

DVT patients with concomitant MTS have a decreased risk of PE compared with those without MTS. This finding extends previous reports of increased PE risk after DVT and calls for better understanding of shared risk factors and underlying mechanisms.

Computed tomography pulmonary angiography versus ventilation-perfusion lung scanning for diagnosing pulmonary embolism during pregnancy: a systematic review and meta-analysis

Differences between computed tomography pulmonary angiography and ventilation-perfusion lung scanning in pregnant patients with suspected acute pulmonary embolism are not well-known, leading to ongoing debate on which test to choose. We searched in PubMed, EMBASE, Web of Science and the Cochrane Library databases and identified all relevant articles and abstracts published up to October 1, 2017. We assessed diagnostic efficiency, frequency of non-diagnostic results and maternal and fetal exposure to radiation exposure. We included 13 studies for the diagnostic efficiency analysis, 30 for the analysis of non-diagnostic results and 22 for the radiation exposure analysis. The pooled rate of false negative test results was 0% for both imaging strategies with overlapping confidence intervals. The pooled rates of non-diagnostic results with computed tomography pulmonary angiography and ventilation-perfusion lung scans were 12% (95% confidence interval: 8-17) and 14% (95% confidence interval: 10-18), respectively. Reported maternal and fetal radiation exposure doses were well below the safety threshold, but could not be compared between the two diagnostic methods given the lack of high quality data. Both imaging tests seem equally safe to rule out pulmonary embolism in pregnancy. We found no significant differences in efficiency and radiation exposures between computed tomography pulmonary angiography and ventilation-perfusion lung scanning although direct comparisons were not possible.

Pulmonary embolism

Pulmonary embolism (PE) is caused by emboli, which have originated from venous thrombi, travelling to and occluding the arteries of the lung. PE is the most dangerous form of venous thromboembolism, and undiagnosed or untreated PE can be fatal. Acute PE is associated with right ventricular dysfunction, which can lead to arrhythmia, haemodynamic collapse and shock. Furthermore, individuals who survive PE can develop post-PE syndrome, which is characterized by chronic thrombotic remains in the pulmonary arteries, persistent right ventricular dysfunction, decreased quality of life and/or chronic functional limitations. Several important improvements have been made in the diagnostic and therapeutic management of acute PE in recent years, such as the introduction of a simplified diagnostic algorithm for suspected PE as well as phase III trials demonstrating the value of direct oral anticoagulants in acute and extended treatment of venous thromboembolism. Future research should aim to address novel treatment options (for example, fibrinolysis enhancers) and improved methods for predicting long-term complications and defining optimal anticoagulant therapy parameters in individual patients, and to gain a greater understanding of post-PE syndrome.

The YEARS algorithm for suspected pulmonary embolism: shorter visit time and reduced costs at the emergency department

Essentials The YEARS algorithm was designed to simplify the diagnostic workup of suspected pulmonary embolism. We compared emergency ward turnaround time of YEARS and the conventional algorithm. YEARS was associated with a significantly shorter emergency department visit time of ˜60 minutes. Treatment of pulmonary embolism was initiated 53 minutes earlier with the YEARS algorithm SUMMARY: Background Recently, the safety of the YEARS algorithm, designed to simplify the diagnostic work-up of pulmonary embolism (PE), was demonstrated. We hypothesize that by design, YEARS would be associated with a shorter diagnostic emergency department (ED) visit time due to simultaneous assessment of pre-test probability and D-dimer level and reduction in number of CT scans. Aim To investigate whether implementation of the YEARS diagnostic algorithm is associated with a shorter ED visit time compared with the conventional algorithm and to evaluate the associated cost savings. Methods We selected consecutive outpatients with suspected PE from our hospital included in the YEARS study and ADJUST-PE study. Different time-points of the diagnostic process were extracted from the to-the-minute accurate electronic patients' chart system of the ED. Further, the costs of the ED visits were estimated for both algorithms. Results All predefined diagnostic turnaround times were significantly shorter after implementation of YEARS: patients were discharged earlier from the ED; 54 min (95% CI, 37-70) for patients managed without computed tomography pulmonary angiography (CTPA) and 60 min (95% CI, 44-76) for the complete study population. Importantly, patients diagnosed with PE by CTPA received the first dose of anticoagulants 53 min (95% CI, 22-82) faster than those managed according to the conventional algorithm. Total costs were reduced by on average €123 per visit. Conclusion YEARS was shown to be associated with a shorter ED visit time compared with the conventional diagnostic algorithm, leading to faster start of treatment in the case of confirmed PE and savings on ED resources.

Thrombogenicity evaluation in 221 patients with haemophilia B treated with nonacog alfa

Risk for thrombotic events with factor IX replacement therapy in patients with haemophilia B remains a concern for patients, those who treat them, and regulatory agencies, based on experience with early use of prothrombin complex concentrates. The current post hoc analysis assessed the incidence of thrombotic events and changes in prothrombin fragment 1 + 2, thrombin–antithrombin complex, and d-dimer in 221 patients with haemophilia B who received nonacog alfa in clinical studies. Thrombotic event and coagulation marker data were collected from 8 interventional studies utilizing on-demand, prophylactic, and preventive regimens in patients with haemophilia B. Mean age was 25 years (min–max, 0–69), with 51 (23%) patients aged less than 12 years and 15 (7%) aged less than 2 years. None tested positive for inhibitors. Mean time on study was 60.9 ± 32 weeks and mean number of exposure days was 69.3 (min–max, 1–496). Sixty-nine (31%) patients regularly received infusions that were approximately 100 IU/kg as part of a routine prophylaxis regimen, and 29 (13%) patients underwent surgical procedures. No clinical thrombotic events were reported, and no patient experienced clinically significant changes in coagulation markers between baseline and end-of-study testing. These collective data support the low thrombotic risk associated with nonacog alfa in paediatric, adult, and surgical patients with haemophilia B receiving different treatment regimens, including doses of approximately 100 IU/kg. Although careful thrombotic clinical evaluation is important, regular coagulation marker monitoring does not appear to be warranted in patients with haemophilia B.

No added value of the age-adjusted D-dimer cut-off to the YEARS algorithm in patients with suspected pulmonary embolism

Essentials Imaging is warranted in the majority of patients to confirm or rule out pulmonary embolism (PE). The age-adjusted D-dimer (ADJUST) reduced the number of required imaging tests in patients ≥ 50 years. The YEARS algorithm was designed to improve the efficiency in patients with suspected PE. There was no added value of implementing ADJUST in the YEARS algorithm in our cohort.

SUMMARY

Background The YEARS algorithm was designed to simplify the diagnostic work-up of pulmonary embolism (PE) and to reduce the number of necessary computed tomography pulmonary angiography (CTPA) scans. An alternative strategy to reduce the number of CTPAs is the age-adjusted D-dimer cut-off (ADJUST) in patients aged 50 years or older. We aimed to investigate whether a combination of both diagnostic strategies might save additional CTPAs. Methods The YEARS algorithm consists of three items (clinical signs of deep venous thrombosis, hemoptysis, 'PE most likely diagnosis') with simultaneous D-dimer testing using a pre-test dependent threshold. We performed a post hoc analysis in 3465 patients managed according to YEARS to compare the number of patients managed without CTPA scans and associated diagnostic failures in hypothetical scenarios with different YEARS-ADJUST combinations. Results Following the YEARS algorithm, 1651 patients (48%) were managed without CTPA; PE was diagnosed in 456 (13%) patients at baseline and 18 patients with initial normal testing suffered venous thromboembolism (VTE) during 3-month follow-up (failure rate 0.61%; 95% confidence interval [CI], 0.36-0.96). If ADJUST had been fully integrated in YEARS, 1627 patients (47%) would have been managed without CTPA (absolute decrease of 0.69%; 95% CI -1.7 to 3.0), at cost of four additional missed PE diagnoses at baseline, for a projected 3-month VTE failure rate of 0.75% (95% CI, 0.49-1.13). None of the other studied scenarios showed relevant improvements in efficiency as well, but all led to more missed diagnoses. Conclusion In our cohort, there was no added value of implementing ADJUST in the YEARS algorithm.

Elevated levels of D-dimers increase the risk of ischaemic and haemorrhagic stroke

Elevated D-dimer levels are reportedly associated with coronary artery disease. It was the study objective to investigate the association of baseline D-dimer levels with strokes that occurred in the European Prospective Investigation into Cancer and Nutrition-Italy cohort. Using a nested case-cohort design, a centre-–stratified sample of 832 subjects (66 % women, age 35–71) was selected as subcohort and compared with 289 strokes in a mean follow-up of nine years. D-dimers were measured by an automated latex-enhanced immunoassay (HemosIL-IL). The multivariable hazard ratios were estimated by a Cox regression model using Prentice method. Individuals with elevated D-dimer levels had significantly higher risk of incident stroke. It was evident from the second quartile (D-dimers > 100 ng/ml) and persisted almost unchanged for higher D-dimers (hazard ratio [HR] 2.10, 95 % confidence interval [CI]: 1.28–3.47; 2.42, 95 %CI: 1.44–4.09 and 2.10, 95 %CI: 1.27–3.48 for the second, third or fourth quartile compared with the lowest quartile, respectively). The association was independent of several confounders, including triglycerides and C-reactive protein. No differences were observed in men and women (P for interaction= 0.46), in hypertensive or non-hypertensive subjects (P for interaction= 0.88) or in subjects with low (< 1 mg/l) or elevated (≥ 1 mg/l) C-reactive protein (P for interaction=0.35). After stratification for stroke type, the hazard ratio for every standard deviation increase was statistically significant both for ischaemic (1.21; 95 %CI: 1.01 to 1.45) and haemorrhagic (1.24; 95 %CI: 1.00 to 1.65) strokes. In conclusion, our data provide clear evidence that elevated levels of D-dimers are potential risk factors not only for ischaemic but also for haemorrhagic strokes.

Troponin I and D-Dimer for Discriminating Acute Pulmonary Thromboembolism from Myocardial Infarction

BACKGROUND

Acute pulmonary thromboembolism (APTE) is a life-threatening condition, often manifesting with chest pain, dyspnea, and increased cardiac biomarkers including cardiac troponin I (CTI) and D-dimer. Therefore, APTE is often misdiagnosed with classical non-ST elevation myocardial infarction (NSTEMI), resulting in unnecessary coronary interventions and a delay of therapy.

OBJECTIVES

Our aim was to distinguish APTE from NSTEMI based on CTI and D-dimer levels.

METHODS

Complete clinical and laboratory data sets from APTE patients (n = 123) were compared with matched NSTEMI patients (n = 123) who presented with chest pain. The APTE diagnosis was confirmed by chest tomography, angiography, or radionuclide ventilation-perfusion scan, while NSTEMI was established by clinical symptoms, cardiac biomarkers, and coronary angiography. Clinical characteristics, CTI (initial and peak), and D-dimer levels at presentation were retrospectively analyzed.

RESULTS

The clinical characteristics were not different between APTE and NSTEMI patients. However, significantly lower initial CTI (0.2 ± 0.5 vs. 4.4 ± 9.5 ng/ml) and peak CTI (0.7 ± 2.7 vs. 17.1 ± 20.4 ng/ml), but higher initial D-dimer (9.8 ± 9.4 vs. 1.6 ± 3.6 ng/ml), distinguished APTE from NSTEMI. By receiver operating characteristic curve analysis, the cutoff values for initial CTI, peak CTI, and D-dimer were 0.25, 0.98, and 3.18 ng/ml, respectively.

CONCLUSION

Patients with APTE exhibited lower initial and peak CTI but higher D-dimer levels than NSTEMI patients. Assessing cardiac biomarkers is useful for differentiating APTE from NSTEMI. Further large randomized biomarker studies are urgently needed to facilitate a better APTE diagnosis since clinical characteristics are not particularly helpful.

Serum microRNA-1233 is a specific biomarker for diagnosing acute pulmonary embolism

Background

Circulating microRNAs (miRNAs) emerge as novel biomarkers in cardiovascular diseases. Diagnosing acute pulmonary embolism (PE) remains challenging due to a diverse clinical presentation and the lack of specific biomarkers. Here we evaluate serum miRNAs as potential biomarkers in acute PE.

Methods

We enrolled 30 patients with acute, CT (computed tomography)-angiographically confirmed central PE and collected serum samples on the day of emergency room admission (1st day) and from 22 of these patients 9 months thereafter. For comparison, we examined serum samples from patients with acute non ST-segment elevation myocardial infarction (NSTEMI, n = 30) and healthy individuals (n = 12).

Results

We randomly selected 16 out of 30 PE patients and screened sera from the acute (1st day) and chronic stages (9 months) for 754 miRNAs using microarrays and found 37 miRNAs to be differentially regulated. Across all miRNAs, miRNA-1233 displayed the highest fold change (FC) from acute to chronic stage (log₂FC 11.5, p < 0.004). We validated miRNA-1233 by real-time quantitative polymerase chain reaction (RT-qPCR). In acute PE (1st day) we found elevated levels of miRNA-1233 in comparison to NSTEMI (log₂FC 5.7, p < 0.0001) and healthy controls (log₂FC 7.7, p < 0.0001). miRNA-1233 differentiated acute PE from NSTEMI patients and healthy individuals with 90 and 90 % sensitivity, and 100 and 92 % specificity [area under the curve (AUC) 0.95, p < 0.001 and 0.91, p < 0.001], respectively.

Conclusions

This is the first report that identifies a miRNA that allows distinguishing acute PE from acute NSTEMI and healthy individuals with high specificity and sensitivity.

Derivation of a clinical prediction score for chronic thromboembolic pulmonary hypertension after acute pulmonary embolism

Essentials Predicting chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism is hard. We studied 772 patients with pulmonary embolism who were followed for CTEPH (incidence 2.8%). Logistic regression analysis revealed 7 easily collectable clinical variables that combined predict CTEPH. Our score identifies patients at low (0.38%) or higher (10%) risk of CTEPH.

SUMMARY

Introduction Validated risk factors for the diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism (PE) are currently lacking. Methods This is a post hoc patient-level analysis of three large prospective cohorts with a total of 772 consecutive patients with acute PE, without major cardiopulmonary or malignant comorbidities. All underwent echocardiography after a median of 1.5 years. In cases with signs of pulmonary hypertension, additional diagnostic tests to confirm CTEPH were performed. Baseline demographics and clinical characteristics of the acute PE event were included in a multivariable regression analysis. Independent predictors were combined in a clinical prediction score. Results CTEPH was confirmed in 22 patients (2.8%) by right heart catheterization. Unprovoked PE, known hypothyroidism, symptom onset > 2 weeks before PE diagnosis, right ventricular dysfunction on computed tomography or echocardiography, known diabetes mellitus and thrombolytic therapy or embolectomy were independently associated with a CTEPH diagnosis during follow-up. The area under the receiver operating charateristic curve (AUC) of the prediction score including those six variables was 0.89 (95% confidence interval [CI] 0.84-0.94). Sensitivity analysis and bootstrap internal validation confirmed this AUC. Seventy-three per cent of patients were in the low-risk category (CTEPH incidence of 0.38%, 95% CI 0-1.5%) and 27% were in the high-risk category (CTEPH incidence of 10%, 95% CI 6.5-15%). Conclusion The 'CTEPH prediction score' allows for the identification of PE patients with a high risk of CTEPH diagnosis after PE. If externally validated, the score may guide targeting of CTEPH screening to at-risk patients.

National Trends in Pulmonary Embolism Hospitalization Rates and Outcomes for Adults Aged ≥65 Years in the United States (1999 to 2010)

Little is known about national trends of pulmonary embolism (PE) hospitalizations and outcomes in older adults in the context of recent diagnostic and therapeutic advances. Therefore, we conducted a retrospective cohort study of 100% Medicare fee-for-service beneficiaries hospitalized from 1999 to 2010 with a principal discharge diagnosis code for PE. The adjusted PE hospitalization rate increased from 129/100,000 person-years in 1999 to 302/100,000 person-years in 2010, a relative increase of 134% (p <0.001). Black patients had the highest rate of increase (174 to 548/100,000 person-years) among all age, gender, and race categories. The mean (standard deviation) length of hospital stay decreased from 7.6 (5.7) days in 1999 to 5.8 (4.4) days in 2010, and the proportion of patients discharged to home decreased from 51.1% (95% confidence interval [CI] 50.5 to 51.6) to 44.1% (95% CI 43.7 to 44.6), whereas more patients were discharged with home health care and to skilled nursing facilities. The in-hospital mortality rate decreased from 8.3% (95% CI 8.0 to 8.6) in 1999 to 4.4% (95% CI 4.2 to 4.5) in 2010, as did adjusted 30-day (from 12.3% [95% CI 11.9 to 12.6] to 9.1% [95% CI 8.5 to 9.7]) and 6-month mortality rates (from 23.0% [95% CI 22.5 to 23.4] to 19.6% [95% CI 18.8 to 20.5]). There were no significant racial differences in mortality rates by 2010. There was no change in the adjusted 30-day all-cause readmission rate from 1999 to 2010. In conclusion, PE hospitalization rates increased substantially from 1999 to 2010, with a higher rate for black patients. All mortality rates decreased but remained high. The increase in hospitalization rates and continued high mortality and readmission rates confirm the significant burden of PE for older adults.

Performance of a diagnostic algorithm based on a prediction rule, D-dimer and CT-scan for pulmonary embolism in patients with previous venous thromboembolism. A systematic review and meta-analysis

Diagnostic management of suspected pulmonary embolism (PE) in patients with a history of venous thromboembolism (VTE) is complicated due to persistent abnormal D-dimer levels, residual embolic obstruction and higher clinical prediction rule (CPR) scores. We aimed to evaluate the safety and efficiency of the standard diagnostic algorithm consisting of a CPR, D-dimer test and computed tomography pulmonary angiography (CTPA) in this specific patient category. We performed a systematic literature search for prospective studies evaluating a diagnostic algorithm in consecutive patients with clinically suspected PE and a history of VTE. The VTE incidence rates during three-month follow-up and the number of indicated CTPAs were pooled using random effect models. Four studies concerning 1,286 patients were included with a pooled baseline PE prevalence of 36 % (95 % confidence interval [CI] 30-42). In only 217 patients (15 %; 95 %CI 11-20) PE could be excluded without CTPA. The three-month VTE incidence rate was 0.8 % (95 %CI 0.06-2.4) in patients managed without CTPA, 1.6 % (95 %CI 0.3-4.0) in patients in whom PE was excluded by CTPA and 1.4 % (95 %CI 0.6-2.7) overall. In the pooled studies, PE was safely excluded in patients with a history of VTE based on a CPR followed by a D-dimer test and/or CTPA, although the efficiency of the algorithm is relatively low compared to patients without a history of VTE.

Pulmonary embolism: current and new treatment options

BACKGROUND

Pulmonary embolism (PE) can be a life-threatening emergency. Accurate diagnostic techniques and patient-specific management strategies are necessary to ensure favorable clinical outcomes.

METHODS

Relevant guidelines, articles, reviews, and abstracts were identified using a narrative approach in PubMed/MEDLINE, Google Scholar, clinicaltrials.gov and nice.org.uk. English-language articles published in 2000-2014 were initially identified using the search terms: novel OAC, pulmonary embolism, venous thromboembolism, diagnosis, treatment, rivaroxaban, apixaban, dabigatran, and edoxaban. The initial literature search was supported by a 'snowballing' style literature search, and relevant articles were included based on a professional judgment of relevance.

SCOPE

We discuss the diagnosis of PE and the categorization of risk for subgroups, which may assist with making treatment decisions. We review current guidance on acute and long-term treatment, possible limitations of traditional anticoagulant therapy, and the development of direct oral anticoagulants, which may significantly alter the management of patients with PE. Finally, we discuss special considerations in high-risk and hard-to-treat subpopulations that may benefit from the improved benefit-risk profile offered by these newer agents.

CONCLUSIONS

The direct oral anticoagulants may overcome several of the limitations associated with traditional anticoagulant therapy, potentially improving the standard of care for PE patients, including high-risk and hard-to-manage subgroups.

Randomised trial of no hydration vs. sodium bicarbonate hydration in patients with chronic kidney disease undergoing acute computed tomography-pulmonary angiography

BACKGROUND

Hydration to prevent contrast-induced acute kidney injury (CI-AKI) induces a diagnostic delay when performing computed tomography-pulmonary angiography (CTPA) in patients suspected of having acute pulmonary embolism.

AIM

To analyze whether withholding hydration is non-inferior to sodium bicarbonate hydration before CTPA in patients with chronic kidney disease (CKD).

METHODS

We performed an open-label multicenter randomized trial between 2009 and 2013. One hundred thirty-nine CKD patients were randomized, of whom 138 were included in the intention-to-treat population: 67 were randomized to withholding hydration and 71 were randomized to 1-h 250 mL 1.4% sodium bicarbonate hydration before CTPA. Primary outcome was the increase in serum creatinine 48-96 h after CTPA. Secondary outcomes were the incidence of CI-AKI (creatinine increase > 25%/> 0.5 mg dL(-1) ), recovery of renal function, and the need for dialysis within 2 months after CTPA. Withholding hydration was considered non-inferior if the mean relative creatinine increase was ≤ 15% compared with sodium bicarbonate.

RESULTS

Mean relative creatinine increase was -0.14% (interquartile range -15.1% to 12.0%) for withholding hydration and -0.32% (interquartile range -9.7% to 10.1%) for sodium bicarbonate (mean difference 0.19%, 95% confidence interval -5.88% to 6.25%, P-value non-inferiority < 0.001). CI-AKI occurred in 11 patients (8.1%): 6 (9.2%) were randomized to withholding hydration and 5 (7.1%) to sodium bicarbonate (relative risk 1.29, 95% confidence interval 0.41-4.03). Renal function recovered in 80.0% of CI-AKI patients within each group (relative risk 1.00, 95% confidence interval 0.54-1.86). None of the CI-AKI patients developed a need for dialysis.

CONCLUSION

Our results suggest that preventive hydration could be safely withheld in CKD patients undergoing CTPA for suspected acute pulmonary embolism. This will facilitate management of these patients and prevents delay in diagnosis as well as unnecessary start of anticoagulant treatment while receiving volume expansion.

Pleuritic chest pain in a young female: a reminder for acute health care providers

Chest pain is one of the most common reasons for emergency department visits. Emergency medicine doctors should focus their initial assessment on patients' stability. History, physical examination, and ancillary testing should exclude serious causes such as acute coronary syndrome, acute aortic syndromes, pulmonary embolism, pneumothorax, esophageal perforation, and rupture as well as pericardial tamponade. Young age should not be used alone as a predictor of a benign condition. Below we present a case of a 24-year-old female who was found to have ascending aortic dissection and was sent for emergent surgery.

Reducing radiation dose in the diagnosis of pulmonary embolism using adaptive statistical iterative reconstruction and lower tube potential in computed tomography

OBJECTIVES

To assess the impact of ASIR (adaptive statistical iterative reconstruction) and lower tube potential on dose reduction and image quality in chest computed tomography angiographies (CTAs) of patients with pulmonary embolism.

MATERIALS AND METHODS

CT data from 44 patients with pulmonary embolism were acquired using different protocols-Group A: 120 kV, filtered back projection, n = 12; Group B: 120 kV, 40 % ASIR, n = 12; Group C: 100 kV, 40 % ASIR, n = 12 and Group D: 80 kV, 40 % ASIR, n = 8. Normalised effective dose was calculated; image quality was assessed quantitatively and qualitatively.

RESULTS

Normalised effective dose in Group B was 33.8 % lower than in Group A (p = 0.014) and 54.4 % lower in Group C than in Group A (p < 0.001). Group A, B and C did not show significant differences in qualitative or quantitative analysis of image quality. Group D showed significantly higher noise levels in qualitative and quantitative analysis, significantly more artefacts and decreased overall diagnosability. Best results, considering dose reduction and image quality, were achieved in Group C.

CONCLUSIONS

The combination of ASIR and lower tube potential is an option to reduce radiation without significant worsening of image quality in the diagnosis of pulmonary embolism.

KEY POINTS

• Iterative algorithms and lowering of tube potential reduce radiation without compromising interpretability • 40 % ASIR and 100 kV tube potential led to a 54.4 % dose reduction • 40 % ASIR and 80 kV tube potential led to significantly worse image quality.

Acute pulmonary embolism following adolescent idiopathic scoliosis correction surgery: case report and review of literature

Pulmonary embolism is a significant complication of surgery. This report presents a case of suspected fatal postoperative acute pulmonary embolism following posterior correction surgery in a 16-year-old female with idiopathic scoliosis. The patient presented with a suspected pulmonary embolism 2 h postoperatively. She lost consciousness quickly, and cardiac respiratory arrest occurred. Cardiopulmonary resuscitation was started immediately. The patient was stabilized but underwent a further suspected pulmonary embolism the following day. Cardiopulmonary resuscitation was performed again, but she lost consciousness and respirator support was required. At 40 days after surgery, a computed tomography scan revealed an area of necrotic brain tissue near the lateral cerebral ventricle. The patient remained in a comatose state for 16 months, after which active management was withdrawn. This case reminds us to be alert to potentially fatal postoperative pulmonary embolism in young patients without any risk factors for thrombosis.

Rivaroxaban for the treatment of pulmonary embolism

With the advent of new oral anticoagulants (NOACs) for the treatment of deep-vein thrombosis (DVT) and/or pulmonary embolism (PE), a new era of oral anticoagulation for patients with venous thromboembolism (VTE) has begun. Rivaroxaban is the first NOAC to receive regulatory approval for the acute and continued treatment of DVT and PE, and for the secondary prevention of VTE. Here, the clinical trials of rivaroxaban in patients with VTE are reviewed, and the clinical use of rivaroxaban for patients with PE is discussed. Even though rivaroxaban will facilitate the therapeutic management of PE, its use in specific clinical situations needs further study.