Complete venous ultrasound in outpatients with suspected pulmonary embolism

Gender differences in the incidence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: A meta-analysis

BACKGROUND

To explore the role of gender in the incidence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism.

METHODS

Two researchers search the PubMed Database, Embase Database and Cochrane Library Database from their establishment to October 2022, using Endnote software for document management and RevMan5.3 software for the meta-analysis of the included literature. A total of 11 studies are selected, including 5788 acute pulmonary embolism events and 391 patients (179 males and 212 females) with chronic thromboembolic pulmonary hypertension (CTEPH) under the stated conditions. The results show that there is no statistically significant difference in the incidence of CTEPH between males and females after PE (P = .28), with combined OR of 0.89 and 95% CI 0.72-1.10.

RESULTS AND CONCLUSIONS

Gender is found to be absent as a factor in the incidence of CTEPH after acute pulmonary embolism. This may indicate that gender is not a risk factor for CTEPH and that female patients are not necessarily more likely to have a higher incidence than male patients. As such, accurate judgments should be made on the possible complications of all patients after acute pulmonary embolism, which will be conducive to early detection and intervention in the treatment of CTEPH.

Upper extremity deep vein thrombosis in COVID-19: Incidence and correlated risk factors in a cohort of non-ICU patients

Background

Venous thromboembolism is a frequent complication of COVID-19 infection. Less than 50% of pulmonary embolism (PE) is associated with the evidence of deep venous thrombosis (DVT) of the lower extremities. DVT may also occur in the venous system of the upper limbs especially if provoking conditions are present such as continuous positive airway pressure (CPAP). The aim of this study was to evaluate the incidence of UEDVT in patients affected by moderate-severe COVID-19 infection and to identify potential associated risk factors for its occurrence.

Methods

We performed a retrospective analysis of all patients affected by moderate-severe COVID-19 infection admitted to our unit. In accordance with the local protocol, all patients had undergone a systematic screening for the diagnosis of UEDVT, by vein compression ultrasonography (CUS). All the patients were receiving pharmacological thromboprophylaxis according to international guidelines recommendations. Univariate and multivariate analyses were used to identify risk factors associated with UEDVT.

Results

257 patients were included in the study, 28 patients were affected by UEDVT with an incidence of 10.9% (95% CI, 7.1–14.7). At univariate analysis UEDVT appeared to be significantly associated (p< 0.05) with pneumonia, ARDS, PaO2/FiO2, D-dimer value higher than the age adjusted cut off value and need for CPAP ventilation. Multivariate analysis showed a significant association between UEDVT and the need for CPAP ventilation (OR 5.95; 95% IC 1.33–26.58). Increased mortality was found in patients affected by UEDVT compared to those who were not (OR 3.71; 95% CI, 1.41–9.78).

Conclusions

UEDVT can occur in COVID-19 patients despite adequate prophylaxis especially in patients undergoing helmet CPAP ventilation. Further studies are needed to identify the correct strategy to prevent DVT in these patients.

Venous thromboembolism

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

Clinical Surveillance vs. Anticoagulation For low-risk patiEnts with isolated SubSegmental Pulmonary Embolism: protocol for a multicentre randomised placebo-controlled non-inferiority trial (SAFE-SSPE)

INTRODUCTION

The clinical significance of subsegmental pulmonary embolism (SSPE) is currently unclear. Although growing evidence from observational studies suggests that withholding anticoagulant treatment may be a safe option in selected patients with isolated SSPE, most patients with this condition receive anticoagulant treatment, which is associated with a 90-day risk of recurrent venous thromboembolism (VTE) of 0.8% and major bleeding of up to 5%. Given the ongoing controversy concerning the risk-benefit ratio of anticoagulation for isolated SSPE and the lack of evidence from randomised-controlled studies, the aim of this clinical trial is to evaluate the efficacy and safety of clinical surveillance without anticoagulation in low-risk patients with isolated SSPE.

METHODS AND ANALYSIS

SAFE-SSPE (Surveillance vs. Anticoagulation For low-risk patiEnts with isolated SubSegmental Pulmonary Embolism, a multicentre randomised placebo-controlled non-inferiority trial) is an international, multicentre, placebo-controlled, double-blind, parallel-group non-inferiority trial conducted in Switzerland, the Netherlands and Canada. Low-risk patients with isolated SSPE are randomised to receive clinical surveillance with either placebo (no anticoagulation) or anticoagulant treatment with rivaroxaban. All patients undergo bilateral whole-leg compression ultrasonography to exclude concomitant deep vein thrombosis before enrolment. Patients are followed for 90 days. The primary outcome is symptomatic recurrent VTE (efficacy). The secondary outcomes include clinically significant bleeding and all-cause mortality (safety). The ancillary outcomes are health-related quality of life, functional status and medical resource utilisation.

ETHICS AND DISSEMINATION

The local ethics committees in Switzerland have approved this protocol. Submission to the Ethical Committees in the Netherlands and Canada is underway. The results of this trial will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04263038.

Detection of factor VIII and D-dimer biomarkers for venous thromboembolism diagnosis using electrochemistry immunosensor

Venous thromboembolism (VTE) is a serious clinical condition which early and accurate diagnosis may contribute to the reduction of associated morbidity and mortality. VTE occurs when a blood clot (thrombus) blocks the vein blood flow causing deep vein thrombosis (DVT) and, when it migrates to the lungs, it may clog the pulmonary arteries characterizing pulmonary embolism (PE). Analysis using fibrin degradation products or D-dimer and coagulation factor VIII may assist early diagnosis of VTE. Thus, two immunosensors were built using layer-by-layer (LbL) films technique, one containing the anti-D-dimer immobilized on polyethylene imine (PEI) and another the anti-FVIII on silk fibroin (SF). Immunosensor response, the antigen-antibody specific interaction, was investigated using cyclic voltammetry. When immunosensors, PEI/anti-D-dimer and SF/anti-FVIII, were exposed to antigens, D-dimer and Factor VIII, the voltammograms area and current were significantly increased with increasing specific antigen concentration. The specific interaction was confirmed with control experiments, electrodes containing only PEI or SF, that no significant changes in the voltammogram responses were observed and principal component analysis confirmed these results. The films formation and response were verified using scanning electronic microscopy (SEM). The developed immunosensor seems to be a promising and effective early complementary exam to assist in the VTE diagnosis, through the combined response of two biomarkers very sensible.

Incidence of deep vein thrombosis among non-ICU patients hospitalized for COVID-19 despite pharmacological thromboprophylaxis

BACKGROUND

A remarkably high incidence of venous thromboembolism (VTE) has been reported among critically ill patients with COVID-19 assisted in the intensive care unit (ICU). However, VTE burden among non-ICU patients hospitalized for COVID-19 that receive guideline-recommended thromboprophylaxis is unknown.

OBJECTIVES

To determine the incidence of VTE among non-ICU patients hospitalized for COVID-19 that receive pharmacological thromboprophylaxis.

METHODS

We performed a systematic screening for the diagnosis of deep vein thrombosis (DVT) by lower limb vein compression ultrasonography (CUS) in consecutive non-ICU patients hospitalized for COVID-19, independent of the presence of signs or symptoms of DVT. All patients were receiving pharmacological thromboprophylaxis with either enoxaparin or fondaparinux.

RESULTS

The population that we screened consisted of 84 consecutive patients, with a mean age of 67.6 ± 13.5 years and a mean Padua Prediction Score of 5.1 ± 1.6. Seventy-two patients (85.7%) had respiratory insufficiency, required oxygen supplementation, and had reduced mobility or were bedridden. In this cohort, we found 10 cases of DVT, with an incidence of 11.9% (95% confidence interval [CI] 4.98-18.82). Of these, 2 were proximal DVT (incidence rate 2.4%, 95% CI -0.87-5.67) and 8 were distal DVT (incidence rate 9.5%, 95% CI 3.23-5.77). Significant differences between subjects with and without DVT were D-dimer > 3000 µg/L (P < .05), current or previous cancer (P < .05), and need of high flow nasal oxygen therapy and/or non-invasive ventilation (P < .01).

CONCLUSIONS

DVT may occur among non-ICU patients hospitalized for COVID-19, despite guideline-recommended thromboprophylaxis.

Definition of pulmonary embolism-related death and classification of the cause of death in venous thromboembolism studies: Communication from the SSC of the ISTH

Pulmonary embolism (PE)-related death is often a component of the primary outcome in venous thromboembolism (VTE) clinical studies. Definitions for PE-related death vary widely, which may lead to biased risk estimates of clinical outcomes, thereby affecting both internal and external validity of study results. We here provide a standardized definition of PE-related death and propose guidance for classification and reporting of the cause of death for clinical studies in VTE. The proposal was developed in a four-step process, including a systematic review of definitions used for PE-related death in previous studies, two subsequent surveys with VTE experts, and meetings held within the Scientific and Standardization Committee (SSC) working group until consensus on the proposal was reached. The proposed classification comprises three categories: Category A: PE-related death, category B: undetermined cause of death, and category C: cause of death other than PE. Category A includes A1: autopsy-confirmed PE in the absence of another more likely cause of death; A2: objectively confirmed PE before death in the absence of another more likely cause of death; and A3: PE is not objectively confirmed, but is most likely the main cause of death. Category B includes B1: cause of death is undetermined, despite available information; and B2: insufficient clinical information available to determine the cause of death. The use of the proposed definition will hopefully improve the accuracy of study outcomes, between-study comparisons, meta-analyses, and validity of future clinical VTE studies.

Development of a standardized definition of pulmonary embolism-related death: A cross-sectional survey of international thrombosis experts

INTRODUCTION

Pulmonary embolism (PE)-related death is often part of the primary outcome in venous thromboembolism (VTE) studies. The Scientific and Standardization Committee (SSC) of the International Society on Thrombosis and Haemostasis developed a definition for PE-related death and classification of the cause of death. The present survey evaluated a preliminary version of this definition and classification.

METHODS

Sixty-nine VTE experts from nine countries were invited for a cross-sectional online survey on January 15, 2019, including multiple-choice and open-ended questions on a seven-subcategory classification of the cause of death. Descriptive statistics were used to describe the results; qualitative comments were summarized.

RESULTS

Forty of 69 (58%) invitees completed the survey. All respondents agreed that guidance on classification of the cause of death in VTE studies is required. There was high agreement on the proposal (median overall score, 6; interquartile range, 6-7; scale from 1 [poor] to 7 [excellent]). All respondents approved the wording and content of the seven subcategories, except for one disagreeing vote for two subcategories (A3: "PE is not objectively confirmed, but is most likely the main cause of death" and C1: "Another cause of death is more likely than PE but has not been objectively confirmed"). Suggestions for improvement mainly concerned the extensiveness of the criteria and clinical situations described to define the cause of death.

CONCLUSION

Acceptance of the proposal was excellent. Suggestions for improvement were incorporated in the SSC communication on the definition of PE-related death and classification of the cause of death in VTE studies.

Comparison of international societal guidelines for the diagnosis of suspected pulmonary embolism during pregnancy

Pregnancy-associated pulmonary embolism is one of the leading causes of maternal mortality. Diagnosis of pulmonary embolism in pregnancy is challenging, with symptoms of pulmonary embolism mimicking those of pregnancy. Several key components such as clinical prediction tools, risk stratification, laboratory tests, and imaging widely used for diagnosis of pulmonary embolism in the non-pregnant population show limitations for diagnosis in pregnancy. Further, because of the difficulty of studying pregnant patients, high-quality research evaluating the performance of these diagnostic components in pregnancy is scarce. Seven international medical society guidelines present clinical diagnostic pathways for evaluation of pulmonary embolism in pregnancy that show conflicting recommendations on the use of these diagnostic components. This Review assesses all key components of diagnostic clinical pathways recommended by guidelines for evaluation of pulmonary embolism in pregnancy, reviews current evidence, compares the guideline recommendations with respect to each key component, and provides our preferred diagnostic pathway. It provides the guidelines and available data needed for informed decision making to diagnose pulmonary embolism in pregnancy.

Multimodality cardiovascular imaging in pulmonary embolism

Acute pulmonary embolism (APE) is one of the leading causes of cardiovascular (CV) morbidity and mortality. To select appropriate therapeutic strategy and/or to minimize the mortality and morbidity, rapid and correct identification of life-threatening APE is very important. Also, right ventricular (RV) failure usually precedes acute hemodynamic compromise or death, and thus the identification of RV failure is another important step in risk stratification or treatment of APE. With advances in diagnosis and treatment, the prognosis of APE has been dramatically improving in most cases, but inadequate therapy or recurrent episodes of pulmonary embolism (PE) may result in negative outcomes or, so called, chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a condition characterized by remaining chronic thromboembolic material in the pulmonary vasculature and subsequent chronic pulmonary hypertension. Various imaging modalities include chest computed tomography pulmonary angiography (CTPA), echocardiography, magnetic resonance imaging, and nuclear imaging and each are used for the assessment of varying status of PE. Assessment of thromboembolic burden by chest CTPA is the first step in the diagnosis of PE. Hemodynamic assessment can be achieved by echocardiography and also by chest CTPA. Nuclear imaging is useful in discriminating CTEPH from APE. Better perspectives on diagnosis, risk stratification and decision making in PE can be provided by combining multimodality CV imaging. Here, the advantages or pitfalls of each imaging modality in diagnosis, risk stratification, or management of PE will be discussed.

The role of cardiovascular ultrasound in diagnosis and management of pulmonary embolism

The diagnosis of acute pulmonary embolism (PE) is one of the most important problems in medical emergencies. Commonly accepted criterion for diagnosis of deep venous thrombosis is the lack of vein compressibility assessed by Compression UltraSonography. Echocardiography represents an easily available and reliable imaging technique in the clinical setting of hemodynamic instability and in the direct visualization of thromboembolic masses in the right heart chambers. Moreover, echocardiography is useful for prognostic stratification after acute PE as right ventricular dysfunction is the most important predictor of mortality in this context. This review aims to highlight usefulness, potentialities and perspectives of standard and advanced echocardiography in evaluating patients affected by PE.

First venous thromboembolism and hormonal contraceptives in young French women

Information on the clinical and biological characteristics of combined hormonal contraceptives (CHC) users experiencing a venous thromboembolism (VTE) event is scarce. Better knowledge of factors determining the VTE risk in CHC users could help identify women at high risk.Data were obtained from a large cohort of consecutive women with the first documented VTE event. Cross-sectional analysis of clinical and biological characteristics of the women was performed.Of the 3009 women with the first VTE included, 31% were nonusers and 69% CHC users at time of VTE. CHC users were significantly younger (29.0 ± 7.2) than nonusers (31.6 ± 7.1) (P < .001). No difference in VTE familial history was observed between the 2 groups. Compared with nonusers, the CHC users experienced more frequently pulmonary embolism: odds ratio (OR) = 1.28 (1.06-1.55; 95% confidence interval [CI]), factor V Leiden mutations were more frequent in this group (OR = 1.41 [1.11-1.80; 95% CI]). Venous sclerotherapy and travel were associated with VTE in CHC users, whereas surgery and bed rest were significantly associated with VTE in nonusers. Finally, 2/3 of CHC users with VTE had additional VTE risk factors.CHC users experiencing the first VTE differ from nonusers with respect to clinical and genetic background. Better understanding of the characteristics of VTE and associated risk factors could allow more appropriate management of these women and contribute to more accurate benefit-risk assessment before prescribing a CHC.

Prevalence of Deep Vein Thrombosis in Hospitalized Patients With Suspected Pulmonary Embolism Ruled Out by Multislice CT Angiography

Current evidence suggests that for outpatients with suspected pulmonary embolism (PE), multislice computed tomographic angiography (CTPA) is sufficient to rule out PE. However, the accuracy of CTPA alone has not been established for hospitalized patients. Our goal was to determine the prevalence of deep vein thrombosis (DVT) in hospitalized patients who had PE ruled out by CTPA. We conducted a prospective cohort study of patients who developed symptoms indicative of PE, after being admitted to the hospital for any reason other than PE and were evaluated with multislice CTPA. The main outcome was proximal DVT. Between November 2011 and December 2014, 191 hospitalized patients were screened. A total of 99 patients satisfied our inclusion criteria. The average length of hospitalization for this group was 14 days (range: 2-127 days). While hospitalized, 54 (28%) patients underwent a major surgical procedure and 80 (79%) were receiving thromboprophylaxis. Of the 99 patients included, 7 (7.07%; 95% confidence intervals [CIs]: 3.4-13.8) were diagnosed with a proximal DVT. The likelihood of developing a proximal DVT was higher for those with subtle and nonspontaneously reported symptoms of DVT, odds ratio [OR] was 50.93 (95% CI: 5.35-2572) and for those classified as PE likely OR was 37.54 (95% CI: 4.05-186.1). Given the prevalence of DVT in hospitalized patients with suspected PE ruled out by a negative multislice CTPA, our study suggests that compression ultrasonography would, in fact, be justified for patients with these characteristics.

Current and future perspectives in imaging of venous thromboembolism

Several thrombus imaging techniques for the diagnosis of venous thromboembolism (VTE) are available. The most prevalent forms of VTE are deep vein thrombosis of the lower extremities and pulmonary embolism. However, VTE may also occur at unusual sites such as deep veins of the upper extremity and the splanchnic and cerebral veins. Currently, the imaging techniques most widely used in clinical practice are compression ultrasonography and computed tomography (CT) pulmonary angiography. Moreover, single-photon emission CT, CT venography, positron emission tomography, and different magnetic resonance imaging (MRI) techniques, including magnetic resonance direct thrombus imaging, have been evaluated in clinical studies. This review provides an overview of the technique, diagnostic accuracy and potential pitfalls of these established and emerging imaging modalities for the different sites of venous thromboembolism.

Diagnostic characteristics of lower limb venous compression ultrasonography in suspected pulmonary embolism: a meta-analysis

Essentials Lower limb ultrasonography (CUS) could be useful in suspected pulmonary embolism (PE). We performed a metaanalysis on the diagnostic characteristics of CUS in suspected PE. With a sensitivity of 41%, proximal CUS would be positive in one of every 7.3 patients. Complete CUS has a higher sensitivity but specificity for PE is too low to use it in suspected PE.

SUMMARY

Background Diagnosis of pulmonary embolism (PE) is commonly based on D-dimer measurement and computed tomography (CT) angiography. Lower limb vein compression ultrasonography (CUS) for diagnosing deep vein thrombosis may be of interest in patients with suspected PE. Objectives We aimed to summarize the data on the diagnostic characteristics of CUS in suspected PE patients. Patients/Methods We conducted a literature review by using PUBMED and EMBASE and included 15 prospective studies in which CUS was performed in consecutive patients with suspected PE. Results Of the 6991 included patients, 2001 (30%) had pulmonary embolism. Eight of the 15 studies included only outpatients, two included hospitalized patients and five involved both in- and outpatients. In 13 studies, only proximal CUS was performed. Two studies analyzed the added value of distal CUS including the calf veins (whole-leg CUS). Pooled estimate of proximal CUS sensitivity was 41% (95% confidence interval [CI], 36-46%) with strong heterogeneity (I square, 79%). Specificity of proximal CUS was 96% (95% CI, 94-98%). The overall positive likelihood ratio for proximal CUS was 11.9 (95% CI, 7.1-19.8), whereas the overall negative likelihood ratio was 0.6 (95% CI, 0.5-0.7). The sensitivity of whole-leg CUS was 79% (95% CI, 24-98%) and specificity was 84% (95% CI, 76-90%). Conclusions Proximal CUS has low sensitivity and cannot be used to rule out PE. Nevertheless, its high specificity allows confirming PE, which may be useful in patients with contraindications to CT angiography. Whole-leg CUS has a higher sensitivity but low specificity for PE and can therefore not be recommended.

Controversies in the diagnosis of venous thromboembolism

Over the last decades, important advances have been made in the diagnosis of venous thromboembolism (VTE). Current diagnostic strategies rely on the sequential use of non-invasive diagnostic tests, based on the pretest clinical probability of disease. Diagnostic tests include D-dimer measurement, leg vein compression ultrasonography, chest computed tomography pulmonary angiography, or ventilation perfusion (V/Q) lung scan. The safety and cost-effectiveness of these strategies have been extensively validated. They have been widely implemented in clinical practice and have replaced the historical gold standard diagnostic tests (venography and pulmonary angiography). However, new challenges arise, including a lower clinical suspicion threshold and concerns on potential over-diagnosis of VTE. Moreover, the diagnostic management remains suboptimal in many subgroups of patients with suspected VTE: patients with prior VTE, pregnant women, or elderly patients.

Point-of-care ultrasound in the diagnosis of pulmonary embolism

The best diagnostic strategy to confirm or exclude pulmonary embolism (PE) suspicion needs an appropriate combination of clinical assessment, plasma D-dimer measurement, and computed tomographic pulmonary angiography (CTPA). CTPA should be used with caution in some patient groups, such as patients with known allergy to contrast media, those with severe renal insufficiency, and pregnant women, and could be not immediately available in case of unstable patients. In the emergency setting, alternative diagnostic strategies should be implemented to overcome CTPA limitations. Ultrasonography is certainly a valuable alternative diagnostic tool. In addition to echocardiography and lower limb compressive venous ultrasonography, lung ultrasound (US) may play an important role in selected patients’ subgroups. Recent data on the diagnostic performance of a triple point-of-care US (lung, heart, and leg vein US) are discussed in the present paper, and pros and cons of triple point-of-care US are compared with those of standard diagnostic approaches.

Is it useful to also image the asymptomatic leg in patients with suspected deep vein thrombosis?

BACKGROUND

Venous ultrasonography is the cornerstone of the diagnostic work-up in patients with suspected deep vein thrombosis (DVT). Significant variations exist in clinical practice between centers and/or countries, e.g. proximal vs. whole-leg ultrasound, serial tests vs. single test, and combination with clinical probability and D-dimer testing. Fewer data exist on the need for bilateral leg imaging.

OBJECTIVES

To assess the yield of bilateral leg ultrasonography in patients with suspected DVT.

PATIENTS AND METHODS

This was a retrospective cohort study of consecutive patients with clinically suspected DVT. A single whole-leg ultrasound scan was performed in all patients. We extracted information on demographics, risk factors, clinical signs, pretest probability, side of clinical suspicion, and ultrasound results.

RESULTS AND CONCLUSIONS

Among the 2804 included patients, 609 (21.8%) patients had a positive ultrasound finding. A total of 20 patients (0.8%; 95% confidence interval [CI] 0.5-1.2%) had a thrombus diagnosed in both the symptomatic leg and asymptomatic leg. Moreover, five patients (0.2%; 95% CI 0.1-0.5%) did not have a thrombus in the symptomatic leg but had a thrombus in the asymptomatic leg. Two of 2540 patients with unilateral symptoms had no proximal DVT in the symptomatic leg and a proximal DVT in the asymptomatic leg (0.08%; 95% CI 0.0-0.3%). In summary, systematic imaging of both legs in patients with suspected DVT has a very low yield, and therefore does not appear to be justified.

Fatal pulmonary embolization after negative serial ultrasounds

BACKGROUND

Isolated distal deep vein thrombosis (DVT) is not traditionally viewed as a potentially life-threatening condition. There are conflicting recommendations regarding its evaluation and treatment, and wide variability in clinical practice. The presentation of this case highlights the fatal potential of this condition.

CASE REPORT

This is the report of a previously healthy young woman who presented to the emergency department with calf pain concerning for a DVT. She received two radiologist-performed duplex ultrasound examinations of the affected extremity, both of which were negative, but suffered a sudden cardiac arrest several hours after the second study. Autopsy attributed the death to DVT and pulmonary embolism. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the risk for fatal pulmonary embolization, even after normal serial ultrasound examinations to exclude DVT.

Effective diagnosis and treatment of pulmonary embolism: Improving patient outcomes

Pulmonary embolism can be life threatening and difficult to diagnose as signs and symptoms are not specific. European guidelines recommend stratification of pulmonary embolism by risk of early mortality. Patients with suspected pulmonary embolism should be assessed for clinical probability of pulmonary embolism using a validated risk score. A low or intermediate clinical probability plus a negative high-sensitivity D-dimer test excludes pulmonary embolism. Anticoagulation is indicated in patients with a positive multidetector computed tomography or high-probability lung scan. An important part of the management of patients with pulmonary embolism has traditionally been anticoagulant treatment with parenteral heparins and oral vitamin K antagonists. Although effective, this dual-drug approach is associated with limitations. Direct oral anticoagulants that may overcome some of these problems have been tested in phase III clinical trials for the treatment of venous thromboembolism. Of these, rivaroxaban and apixaban have demonstrated non-inferiority to standard therapy when given as single-drug approaches for venous thromboembolism treatment, and provided significant reductions in major bleeding rates. Dabigatran and edoxaban were non-inferior to standard therapy when given as part of a dual-drug approach after initial parenteral anticoagulation, and reduced clinically relevant bleeding rates. There may be a benefit to extended anticoagulation with direct oral anticoagulants for the prevention of recurrent venous thromboembolism. Registry studies will provide more information on the use of these agents in real-world populations. Accurate diagnosis and risk stratification of patients with pulmonary embolism, together with simplified anticoagulation therapy, is likely to improve outcomes.

Diagnostic value of single complete compression ultrasonography in pregnant and postpartum women with suspected deep vein thrombosis: prospective study

OBJECTIVE

To assess the safety of using single complete compression ultrasonography in pregnant and postpartum women to rule out deep vein thrombosis.

DESIGN

Prospective outcome study.

SETTING

Two tertiary care centres and 18 private practices specialising in vascular medicine in France and Switzerland.

PARTICIPANTS

226 pregnant and postpartum women referred for suspected deep vein thrombosis.

METHODS

A single proximal and distal compression ultrasonography was performed. All women with a negative complete compression ultrasonography result did not receive anticoagulant therapy and were followed up for a three month period.

MAIN OUTCOME MEASURES

Symptoms of venous thromboembolism, second compression ultrasonography or chest imaging, a thromboembolic event, and anticoagulant treatment.

RESULTS

16 women were excluded, mainly because of associated suspected pulmonary embolism. Deep vein thrombosis was diagnosed in 22 out of the 210 included women (10.5%). 10 patients received full dose anticoagulation despite a negative test result during follow-up. Of the 177 patients without deep vein thrombosis and who did not receive full dose anticoagulant therapy, two (1.1%, 95% confidence interval 0.3% to 4.0%) had an objectively confirmed deep vein thrombosis during follow-up.

CONCLUSIONS

The rate of venous thromboembolic events after single complete compression ultrasonography in pregnant and postpartum women seems to be within the range of that observed in studies in the non-pregnant population. These data suggest that a negative single complete compression ultrasonography result may safely exclude the diagnosis of deep vein thrombosis in this setting.

TRIAL REGISTRATION

clinicaltrials.gov NCT00740454.

ACR Appropriateness Criteria(®) on suspected lower extremity deep vein thrombosis

Lower extremity deep vein thrombosis (DVT) is a common clinical concern, with an incidence that increases with advanced age. DVT typically begins below the knee but may extend proximally and result in pulmonary embolism. Pulmonary embolism can occur in 50% to 60% of patients with untreated DVT and can be fatal. Although clinical examination and plasma d-dimer blood evaluation can often predict the presence of DVT, imaging remains critical for the diagnostic confirmation and treatment planning of DVT. Patients with above-the-knee or proximal DVT have a high risk for pulmonary embolism and are recommended to receive anticoagulation therapy. On the other hand, patients with below-the-knee or distal DVT rarely experience pulmonary embolism, and anticoagulation therapy in these patients remains controversial. However, one sixth of patients with distal DVT may experience extension of their thrombus above the knee and therefore are recommended to undergo serial imaging assessment at 1 week to exclude proximal DVT extension if anticoagulation therapy is not initiated. Ultrasound is the preferred imaging method for evaluation of patients with newly suspected lower extremity DVT. Magnetic resonance and CT venography can be especially helpful for the evaluation of suspected DVT in the pelvis and thigh. Contrast x-ray venography, the historic gold standard for DVT assessment, is now less commonly performed and primarily reserved for patients with more complex presentations such as those with suspected recurrent acute DVT.

Isolated distal deep vein thrombosis: what we know and what we are doing

Thromboses that are restricted to the infra-popliteal deep veins of the lower limbs (isolated distal deep vein thrombosis, IDDVT) are frequently diagnosed in subjects with suspected pulmonary embolism (PE; 7–10%) or DVT(4–15%), accounting for 31–56% of all diagnosed leg DVTs. Despite their frequency, IDDVTs still remain one of the most debated issues in the field of venous thromboembolism (VTE). Conflicting clinical results have resulted in differing opinions on the need to test for IDDVTs and how to treat them. Due to discordant results, the real risk of IDDVT-associated PE is not well established. IDDVTs are associated with (i) lower risk of recurrence when compared with other VTEs, and (ii) fewer late sequelae than proximal DVT. Diagnosis of IDDVT is based on ultrasound examination of all calf veins, which is more operator-dependent and less sensitive than proximal vein examination. A series of studies has shown, however, that a single complete ultrasound strategy in symptomatic patients has comparable clinical results to serial proximal ultrasound, allowing approximately 15% better DVT diagnosis. Optimal treatment of IDDVT is still controversial. Guidelines recommend anticoagulation for 12 weeks, although 6 weeks may be sufficient. There is, however, insufficient data to support the diagnosis and treatment of all IDDVTs, and the necessary criteria to identify subjects at higher risk of complication are lacking. It also seems likely that different approaches may be better for unprovoked or secondary events and for deep or muscle veins. Specifically designed and adequately powered clinical studies addressing the issue of IDDVT need to be urgently undertaken.

Clinical prediction of pulmonary embolism in respiratory emergencies

INTRODUCTION

The initial management of suspected pulmonary embolism (PE) is commonly done in respiratory departments, but is based on clinical prediction rules developed in other settings.

OBJECTIVE

To determine the accuracy of established prediction rules for PE in patients with respiratory emergencies.

DESIGN

A prospective study

MATERIALS AND METHODS

Patients presenting to respiratory emergency department with acute symptoms and signs suggestive of PE (n=183) and subsequently admitted to hospital were prospectively enrolled. Wells' rule, original and revised Geneva scores, their components separately, and other common clinical parameters were recorded during admission. PE was diagnosed by perfusion lung scanning, computed tomographic pulmonary angiography, lower limb venous ultrasonography, magnetic resonance pulmonary angiography, and/or pulmonary angiography.

RESULTS

PE was confirmed in 52 and ruled out in 131 patients. Tachycardia, atelectasis, elevated hemidiaphragm, clinical signs of deep-venous thrombosis, physician perception that PE is the likeliest diagnosis, previous thromboembolism, chest pain, and absence of chronic obstructive pulmonary disease or cough were associated with the presence of PE. These significant parameters could be combined for accurate pre-test PE prediction, with a newly devised combinatorial tool exhibiting the highest area under curve [0.92 (95% CI: 0.87-0.97)], followed by Wells' rule [0.86 (95% CI 0.79-0.92)], the revised Geneva score [0.83 (95% CI 0.77-0.90)], and the original Geneva score [0.75 (95% CI 0.68-0.83)].

CONCLUSION

Wells' rule and the revised Geneva score are more useful in diagnosing PE in respiratory emergencies. A newly devised prediction tool can be of even greater accuracy in this patient population.

Cost-effectiveness of lower extremity compression ultrasound in emergency department patients with a high risk of hemodynamically stable pulmonary embolism

BACKGROUND

Computed tomography angiograms (CTAs) for patients with suspected pulmonary embolism (PE) are being ordered with increasing frequency from the emergency department (ED). Strategies are needed to safely decrease the utilization of CTs to control rising health care costs and minimize the associated risks of anaphylaxis, contrast-induced nephropathy, and radiation-induced carcinogenesis. The use of compression ultrasonography (US) to identify deep vein thromboses (DVTs) in hemodynamically stable patients with signs and symptoms suggestive of PE is highly specific for the diagnosis of PE and may represent a cost-effective alternative to CT imaging.

OBJECTIVES

  The objective was to analyze the cost-effectiveness of a selective CT strategy incorporating the use of compression US to diagnose and treat DVT in patients with a high pretest probability of PE.

METHODS

The authors constructed a decision analytic model to evaluate the scenario of an otherwise healthy 59-year-old female in whom PE was being considered as a diagnosis. Two strategies were used. The selective CT strategy began with a screening compression US. Negative studies were followed up with a CTA, while patients with positive studies identifying a DVT were treated as though they had a PE and were anticoagulated. The universal CT strategy used CTA as the initial test, and anticoagulation was based on the CT result. Costs were estimated from the 2009 Medicare data for hospital reimbursement, and professional fees were obtained from the 2009 National Physician Fee Schedule. Clinical probabilities were obtained from existing published data, and sensitivity analyses were performed across plausible ranges for all clinical variables.

RESULTS

In the base case, the selective CT strategy cost $1,457.70 less than the universal CT strategy and resulted in a gain of 0.0213 quality-adjusted life-years (QALYs). Sensitivity analyses confirm that the selective CT strategy is dominant above both a pretest probability for PE of 8.3% and a compression US specificity of 87.4%.

CONCLUSIONS

A selective CT strategy using compression US is cost-effective for patients provided they have a high pretest probability of PE. This may reduce the need for, and decrease the adverse events associated with, CTAs.

[Diagnostic strategy and comparison of clinical scores for pulmonary embolism]

The diagnostic approach to pulmonary embolism can be divided in several consecutive steps. First of all, the clinician must identify the patients with potential pulmonary embolism based on clinical presentation and the presence or absence of personal risk factors. Further investigations can then be guided by the use of a clinical probability score. The revised Geneva score and the Wells score are the most validated tools. They are reliable in stratifying patients into low, intermediate, and high-risk categories. When clinical probability is low or intermediate, the dosage of d-dimers is helpful. A negative result excludes pulmonary embolism with a very high negative predictive value, close to 100%. When positive, a multidetector thoracic CT will confirm or exclude the diagnosis. The utility of a lower-limb venous ultrasound is very low, and its use is therefore no longer recommended.

Cost-effective diagnostic strategies in patients with a high, intermediate, or low clinical probability of pulmonary embolism

Rapid quantitative D-dimer assays (DD), lower extremity venous duplex ultrasonography (US), and multislice computed tomographic (CT) angiography have been shown to have adequate sensitivities and specificities for diagnostic purpose. The purpose of this study was to evaluate cost-effectiveness of diagnostic strategies for pulmonary embolism (PE) in patients with a high, intermediate, or low clinical probability of PE. A formal cost-effectiveness analysis for the diagnosis of PE was performed. The main outcome measure for effectiveness was 3-month expected survival. The strategy of DD followed by CT was cost-effective and had the lowest cost per life saved for all patients suspected with PE. The conventional strategy including ventilation and perfusion lung scanning followed by pulmonary angiography (PA) or CT was not cost-effective. The leg US after CT was not also cost-effective. In clinical practice, the individual patient's condition should be considered when choosing appropriate diagnostic tests.

Computerized tomographic pulmonary angiography versus ventilation perfusion lung scanning for the diagnosis of pulmonary embolism

PURPOSE OF REVIEW

The purpose of this review is to focus on recent research that has addressed the relative merits of computed tomographic pulmonary angiography (CTPA) and ventilation perfusion (V/Q) scanning for the diagnosis of pulmonary embolism.

RECENT FINDINGS

Computed tomographic pulmonary angiography is the most sensitive test for the diagnosis of pulmonary embolism and its use has been associated with a rising incidence of the condition. Diagnostic algorithms using either CTPA or V/Q scanning have proven to be comparably safe to exclude the diagnosis of pulmonary embolism. Negative multidetector CTPA study results essentially ruled out the diagnosis of pulmonary embolism without the need to routinely exclude the presence of deep vein thrombosis. Use of multidetector CTPA was associated with significant radiation exposure that potentially increases risk of secondary malignancies. This is particularly a concern for young women given the risk of breast cancer. Single photon emission tomography (SPECT) V/Q and modified diagnostic criteria for V/Q scan interpretation increased their diagnostic accuracy compared with V/Q scanning and offer nuclear medicine modalities that are alternatives to CTPA in at least some patients with suspected pulmonary embolism at a fraction of the risk of radiation exposure. Excluding low risk patients for pulmonary embolism as defined by clinical scoring systems and D-dimer testing would enhance the yield of diagnostic testing.

SUMMARY

Computed tomographic pulmonary angiography is the most reliable test for diagnosis of pulmonary embolism. However, diagnostic algorithms using V/Q scanning are safe and may be preferred in some patient populations.