Prognostic clinical prediction rules to identify a low-risk pulmonary embolism: a systematic review and meta-analysis

Acute Pulmonary Embolism: A Review

IMPORTANCE

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

OBSERVATIONS

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

CONCLUSIONS AND RELEVANCE

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

Acute pulmonary embolism multimodality imaging prior to endovascular therapy

The manuscript discusses the application of CT pulmonary angiography, ventilation–perfusion scan, and magnetic resonance angiography to detect acute pulmonary embolism and to plan endovascular therapy. CT pulmonary angiography offers high accuracy, speed of acquisition, and widespread availability when applied to acute pulmonary embolism detection. This imaging modality also aids the planning of endovascular therapy by visualizing the number and distribution of emboli, determining ideal intra-procedural catheter position for treatment, and signs of right heart strain. Ventilation–perfusion scan and magnetic resonance angiography with and without contrast enhancement can also aid in the detection and pre-procedural planning of endovascular therapy in patients who are not candidates for CT pulmonary angiography.

Outpatient management of pulmonary emboli: when to ambulate

Pulmonary embolism is a potentially fatal consequence of venous thromboembolism and constitutes a significant proportion of the acute medical take. Standard management has previously required admission of all patients presenting with acute pulmonary embolism for initiation of anticoagulation and initial investigations. However, clinical trial data have demonstrated the feasibility and safety of managing a subset of patients with low-risk pulmonary embolism in the outpatient setting and this has since been reflected in national guidelines. This article provides a practical overview for general physicians with regards to identifying patients with low-risk pulmonary embolism, and when and how to manage these patients on an outpatient basis.

Usefulness of Simplified Pulmonary Embolism Severity Index Score for Identification of Patients With Low-Risk Pulmonary Embolism and Active Cancer: From the COMMAND VTE Registry

BACKGROUND

The simplified Pulmonary Embolism Severity Index (sPESI) score is a practical score for identification of patients with low-risk pulmonary embolism (PE), although it has not been applied in patients with active cancer. The current study aimed to evaluate the usefulness of the sPESI score in patients with PE and active cancer.

METHODS

The COMMAND VTE Registry is a multicenter registry enrolling consecutive patients with acute symptomatic VTE. The current study population consisted of 368 patients with PE and active cancer. The 30-day clinical outcomes were compared between patients with sPESI score = 1 and patients with sPESI scores ≥ 2.

RESULTS

Overall, 37 patients (10%) died during the 30 days after diagnosis. The cumulative 30-day incidences of mortality, and PE-related death, were lower in patients with sPESI score = 1 than in patients with sPESI scores ≥ 2 (6.3% vs 13.1%; log-rank P = .03; and 0.7% vs 3.9%; log-rank P = .046). Among patients with sPESI score = 1, the predominant cause of death was cancer. There were no significant differences in the cumulative 30-day incidence of recurrent VTE and major bleeding between the two groups (3.9% vs 5.6%; log-rank P = .46; and 6.4% vs 4.5%; log-rank P = .45).

CONCLUSIONS

Among patients with PE and active cancer, patients with sPESI score = 1 had a lower 30-day mortality rate compared with patients with sPESI scores ≥ 2, and they showed very low PE-related mortality risk, although the overall mortality rate remained high because of cancer-related mortality. They also showed relatively high risks for recurrence and major bleeding, suggesting the need for careful follow-up.

TRIAL REGISTRY

UMIN Clinical Trials Registry; No.: UMIN000021132; URL: http://www.umin.ac.jp/ctr/index.htm.

Interventional Therapies for Acute Pulmonary Embolism: Current Status and Principles for the Development of Novel Evidence: A Scientific Statement From the American Heart Association

Pulmonary embolism (PE) represents the third leading cause of cardiovascular mortality. The technological landscape for management of acute intermediate- and high-risk PE is rapidly evolving. Two interventional devices using pharmacomechanical means to recanalize the pulmonary arteries have recently been cleared by the US Food and Drug Administration for marketing, and several others are in various stages of development. The purpose of this document is to clarify the current state of endovascular interventional therapy for acute PE and to provide considerations for evidence development for new devices that will define which patients with PE would derive the greatest net benefit from their use in various clinical settings. First, definitions and limitations of commonly used risk stratification tools for PE are reviewed. An adjudication of risks and benefits of available interventional therapies for PE follows. Next, considerations for optimal future evidence development in this field are presented in the context of the current US regulatory framework. Finally, the document concludes with a discussion of the pros and cons of the rapidly expanding PE response team model of care delivery.

Acute pulmonary embolism: a concise review of diagnosis and management

An acute pulmonary embolism (aPE) is characterised by occlusion of one or more pulmonary arteries. Physiological disturbance may be minimal, but often cardiac output decreases as the right ventricle attempts to overcome increased afterload. Additionally, ventilation-perfusion mismatches can develop in affected vascular beds, reducing systemic oxygenation. Incidence is reported at 50-75 per 100 000 in Australia and New Zealand, with 30-day mortality rates ranging from 0.5% to over 20%. Incidence is likely to increase with the ageing population, increased survival of patients with comorbidities that are considered risk factors and improving sensitivity of imaging techniques. Use of clinical prediction scores, such as the Wells score, has assisted in clinical decision-making and decreased unnecessary radiological investigations. However, imaging (i.e. computed tomography pulmonary angiography or ventilation-perfusion scans) is still necessary for objective diagnosis. Anti-coagulation remains the foundation of PE management. Haemodynamically unstable patients require thrombolysis unless absolutely contraindicated, while stable patients with right ventricular dysfunction or ischaemia should be aggressively anti-coagulated. Stable patients with no right ventricular dysfunction can be discharged home early with anti-coagulation and review. However, treatment should be case dependent with full consideration of the patient's clinical state. Direct oral anti-coagulants have become an alternative to vitamin K antagonists and are facilitating shorter hospital admissions. Additionally, duration of anti-coagulation must be decided by considering any provoking factors, bleeding risk and comorbid state. Patients with truly unprovoked or idiopathic PE often require indefinite treatment, while in provoked cases it is typically 3 months with some patients requiring longer periods of 6-12 months.

Development and Performance of the Pulmonary Embolism Result Forecast Model (PERFORM) for Computed Tomography Clinical Decision Support

IMPORTANCE

Pulmonary embolism (PE) is a life-threatening clinical problem, and computed tomographic imaging is the standard for diagnosis. Clinical decision support rules based on PE risk-scoring models have been developed to compute pretest probability but are underused and tend to underperform in practice, leading to persistent overuse of CT imaging for PE.

OBJECTIVE

To develop a machine learning model to generate a patient-specific risk score for PE by analyzing longitudinal clinical data as clinical decision support for patients referred for CT imaging for PE.

DESIGN, SETTING, AND PARTICIPANTS

In this diagnostic study, the proposed workflow for the machine learning model, the Pulmonary Embolism Result Forecast Model (PERFORM), transforms raw electronic medical record (EMR) data into temporal feature vectors and develops a decision analytical model targeted toward adult patients referred for CT imaging for PE. The model was tested on holdout patient EMR data from 2 large, academic medical practices. A total of 3397 annotated CT imaging examinations for PE from 3214 unique patients seen at Stanford University hospitals and clinics were used for training and validation. The models were externally validated on 240 unique patients seen at Duke University Medical Center. The comparison with clinical scoring systems was done on randomly selected 100 outpatient samples from Stanford University hospitals and clinics and 101 outpatient samples from Duke University Medical Center.

MAIN OUTCOMES AND MEASURES

Prediction performance of diagnosing acute PE was evaluated using ElasticNet, artificial neural networks, and other machine learning approaches on holdout data sets from both institutions, and performance of models was measured by area under the receiver operating characteristic curve (AUROC).

RESULTS

Of the 3214 patients included in the study, 1704 (53.0%) were women from Stanford University hospitals and clinics; mean (SD) age was 60.53 (19.43) years. The 240 patients from Duke University Medical Center used for validation included 132 women (55.0%); mean (SD) age was 70.2 (14.2) years. In the samples for clinical scoring system comparisons, the 100 outpatients from Stanford University hospitals and clinics included 67 women (67.0%); mean (SD) age was 57.74 (19.87) years, and the 101 patients from Duke University Medical Center included 59 women (58.4%); mean (SD) age was 73.06 (15.3) years. The best-performing model achieved an AUROC performance of predicting a positive PE study of 0.90 (95% CI, 0.87-0.91) on intrainstitutional holdout data with an AUROC of 0.71 (95% CI, 0.69-0.72) on an external data set from Duke University Medical Center; superior AUROC performance and cross-institutional generalization of the model of 0.81 (95% CI, 0.77-0.87) and 0.81 (95% CI, 0.73-0.82), respectively, were noted on holdout outpatient populations from both intrainstitutional and extrainstitutional data.

CONCLUSIONS AND RELEVANCE

The machine learning model, PERFORM, may consider multitudes of applicable patient-specific risk factors and dependencies to arrive at a PE risk prediction that generalizes to new population distributions. This approach might be used as an automated clinical decision-support tool for patients referred for CT PE imaging to improve CT use.

[Evaluation of the management of low-risk pulmonary embolism diagnosed in an emergency department. HoPE study (Home treatment of Pulmonary Embolism)]

INTRODUCTION

Risk stratification allows outpatient management of low-risk pulmonary embolism (PE). Here, we carry out an evaluation of the professional practices on the emergency management of low-risk PE, after selection with the sPESI score.

MATERIAL AND METHOD

All patients admitted to the emergency department of Chambéry hospital, with a final diagnosis of PE are analyzed. The PE of score sPESI at 0 are included, in the absence of contraindications. Ninety-day follow-up is done. The objective is to evaluate the proportion of ambulatory care for low-risk patients.

RESULTS

Eighty PE were diagnosed in 2016, 28 with sPESI score at 0 and 3 patients excluded. Of the 25 inclusions, 6 patients had signs of right ventricular dysfunction and were therefore hospitalized. The remaining 19 were eligible for outpatient care but only 8 of them stayed less than 24hours in the hospital.

DISCUSSION

The sPESI score is a decision support tool for outpatient management but should not be used alone. The search for right ventricular dysfunction seems important here.

Validation of simplified PESI score for identification of low-risk patients with pulmonary embolism: From the COMMAND VTE Registry

Background:

The simplified pulmonary embolism severity index (sPESI) score has been reported to be useful in predicting 30-day mortality for patients with pulmonary embolism, which helps the identification of low-risk patients for early hospital discharge or home treatment. However, therapeutic decision-making should also be based on the risks of adverse events other than mortality.

Methods:

The COMMAND VTE Registry is a multicentre registry enrolling consecutive patients with acute symptomatic venous thromboembolism in Japan between January 2010 and August 2014, and the current study population consisted of 1715 patients with pulmonary embolism. We calculated the sPESI score for each patient, and compared 30-day rates of mortality, recurrent venous thromboembolism and major bleeding between sPESI scores of 0 and 1 or greater.

Results:

Patients with a sPESI score of 0 accounted for 383 (22%) patients, and 110 (6.4%) patients died within 30 days. The cumulative 30-day incidence of mortality was lower in patients with a sPESI score of 0 than those with a sPESI score of 1 or greater (0.5% vs. 8.1%, log rank P<0.001). There was no significant difference in the cumulative 30-day incidence of recurrent venous thromboembolism between patients with a sPESI score of 0 and 1 or greater (1.3% vs. 2.8%, log rank P=0.11). The cumulative 30-day incidence of major bleeding was lower in patients with a sPESI score of 0 than those with a sPESI score of 1 or greater (1.1% vs. 4.0%, log rank P=0.005).

Conclusions:

In patients with a sPESI score of 0, the 30-day mortality, recurrent venous thromboembolism and major bleeding rates were reasonably low. The sPESI score could be useful to identify candidates for early hospital discharge or home treatment.

Assessment of coexisting deep vein thrombosis for risk stratification of acute pulmonary embolism

BACKGROUND

In patients with acute pulmonary embolism (PE), studies have shown an association between coexisting deep vein thrombosis (DVT) and short-term prognosis. It is not known whether complete compression ultrasound testing (CCUS) improves the risk stratification of their disease beyond the recommended prognostic models.

METHODS

We included patients with normotensive acute symptomatic PE and prognosticated them with the European Society of Cardiology (ESC) risk model for PE. Subsequently, we determined the prognostic significance of coexisting DVT in patients with various ESC risk categories. The primary endpoint was a complicated course after the diagnosis of PE, defined as death from any cause, haemodynamic collapse, or adjudicated recurrent PE.

RESULTS

According to the ESC model, 37% of patients were low-risk, 56% were intermediate-low risk, and 6.7% were intermediate-high risk. CCUS demonstrated coexisting DVT in 375 (44%) patients. Among the 313 patients with low-risk PE, coexisting DVT (46%) did not show a significant increased risk of complicated course (2.8%; 95% confidence interval [CI], 0.8%-7.0%), compared with those without DVT (0.6%; 95% CI, 0%-3.2%), (P = 0.18). Of the 478 patients with intermediate-low risk PE, a complicated course was 14% and 6.8% for those with and without DVT, respectively (P = 0.01). Of the 57 patients that had intermediate-high risk PE, a complicated course occurred in 17% and 18% for those with and without DVT, respectively (P = 1.0).

CONCLUSIONS

In normotensive patients with PE, testing for coexisting DVT might improve risk stratification of patients at intermediate-low risk for short-term complications.

The long-term prognostic value of highly sensitive cardiac troponin I in patients with acute pulmonary embolism

BACKGROUND

In patients with acute pulmonary embolism (PE), detectable levels of cardiac troponin I (cTnI) using a highly sensitive assay have been associated with increased in-hospital mortality. We sought to investigate the impact of detectable cTnI on long-term survival following acute PE.

HYPOTHESIS

Detectable cTnI levels in patients presenting with acute PE predict increased long-term mortality following hospital discharge.

METHODS

In a retrospective cohort study, we analyzed consecutive patients with confirmed acute PE and cTnI assay available from the index hospitalization. The detectable cTnI level was ≥0.012 ng/mL. Patients were classified into low and high clinical risk groups according to the Pulmonary Embolism Severity Index (PESI) at presentation. Subjects were followed for all-cause mortality subsequent to hospital discharge using chart review and Social Security Death Index.

RESULTS

A cohort of 289 acute PE patients (mean age 56 years, 51% men), of whom 152 (53%) had a detectable cTnI, was followed for a mean of 3.1 ± 1.8 years after hospital discharge. A total of 71 deaths were observed; 44 (29%) and 27 (20%) in the detectable and undetectable cTnI groups, respectively (P = 0.05). Detectable cTnI was predictive of long-term survival among low-risk (P = 0.009) but not high-risk patients (P = 0.78) who had high mortality rates irrespective of cTnI status.

CONCLUSIONS

In patients with acute PE, detectable cTnI is predictive of long-term mortality, particularly among patients who were identified as low risk according to PESI score.

Frequency of use and acceptability of clinical prediction rules for pulmonary embolism among Swiss general internal medicine residents

INTRODUCTION

Whether clinical prediction rules for pulmonary embolism are accepted and used among general internal medicine residents remains uncertain. We therefore evaluated the frequency of use and acceptability of the Revised Geneva Score (RGS) and the Pulmonary Embolism Severity Index (PESI), and explored which factors were associated with rule use.

MATERIALS/METHODS

In an online survey among general internal medicine residents from 10 Swiss hospitals, we assessed rule acceptability using the Ottawa Acceptability of Decision Rules Instrument (OADRI) and explored the association between physician and training-related factors and rule use using mixed logistic regression models.

RESULTS

The response rate was 50.4% (433/859). Overall, 61% and 36% of the residents reported that they always or regularly use the RGS and the PESI, respectively. The mean overall OADRI score was 4.3 (scale 0-6) for the RGS and 4.1 for the PESI, indicating a good acceptability. Rule acceptability (odds ratio [OR] 6.19 per point, 95% confidence interval [CI] 3.64-10.51), prior training in emergency medicine (OR 5.14, CI 2.20-12.01), and availability of internal guidelines recommending RGS use (OR 4.25, CI 2.15-8.43) were associated with RGS use. Rule acceptability (OR 6.43 per point, CI 4.17-9.92) and rule taught at medical school (OR 2.06, CI 1.24-3.43) were associated with PESI use.

CONCLUSIONS

The RGS was more frequently used than the PESI. Both rules were considered acceptable. Rule acceptability, prior training in emergency medicine, availability of internal guidelines, and rule taught at medical school were associated with rule use and represent potential targets for quality improvement interventions.

Benefit of early discharge among patients with low-risk pulmonary embolism

Clinical guidelines recommend early discharge of patients with low-risk pulmonary embolism (LRPE). This study measured the overall impact of early discharge of LRPE patients on clinical outcomes and costs in the Veterans Health Administration population. Adult patients with ≥1 inpatient diagnosis for pulmonary embolism (PE) (index date) between 10/2011-06/2015, continuous enrollment for ≥12 months pre- and 3 months post-index date were included. PE risk stratification was performed using the simplified Pulmonary Embolism Stratification Index. Propensity score matching (PSM) was used to compare 90-day adverse PE events (APEs) [recurrent venous thromboembolism, major bleed and death], hospital-acquired complications (HACs), healthcare utilization, and costs among short (≤2 days) versus long length of stay (LOS). Net clinical benefit was defined as 1 minus the combined rate of APE and HAC. Among 6,746 PE patients, 95.4% were men, 22.0% were African American, and 1,918 had LRPE. Among LRPE patients, only 688 had a short LOS. After 1:1 PSM, there were no differences in APE, but short LOS had fewer HAC (1.5% vs 13.3%, 95% CI: 3.77–19.94) and bacterial pneumonias (5.9% vs 11.7%, 95% CI: 1.24–3.23), resulting in better net clinical benefit (86.9% vs 78.3%, 95% CI: 0.84–0.96). Among long LOS patients, HACs (52) exceeded APEs (14 recurrent DVT, 5 bleeds). Short LOS incurred lower inpatient ($2,164 vs $5,100, 95% CI: $646.8-$5225.0) and total costs ($9,056 vs $12,544, 95% CI: $636.6-$6337.7). LRPE patients with short LOS had better net clinical outcomes at lower costs than matched LRPE patients with long LOS.

Derivation and Validation of a Novel Prediction Model to Identify Low-Risk Patients With Acute Pulmonary Embolism

Accurate identification of low-risk patients with acute pulmonary embolism (PE) who may be eligible for outpatient treatment or early discharge can have substantial cost-saving benefit. The purpose of this study was to derive and validate a prediction model to effectively identify patients with PE at low risk of short-term mortality, right ventricular dysfunction, and other nonfatal outcomes. This study analyzed data from 400 consecutive patients with acute PE. We derived and internally validated our prediction rule based on clinically significant variables that are routinely available at initial examination and that were categorized and weighted using coefficients in the multivariate logistic regression. The model was externally validated in an independent cohort of 82 patients. The final model (HOPPE score) consisted of 5 categorized patient variables (1, 2, or 3 points, respectively): systolic blood pressure (>120, 100 to 119, <99 mm Hg), diastolic blood pressure (>80, 65 to 79, <64 mm Hg), heart rate (<80, 81 to 100, >101 beats/min), arterial partial pressure of oxygen (>80, 60 to 79, <59 mm Hg), and modified electrocardiographic score (<2, 2 to 4, >4). The 30-day mortality rates were 0% in low risk (0 to 6 points), 7.5% to 8.5% in intermediate risk (7 to 10), and 18.2% to 18.8% in high-risk patients (≥11) across the derivation and validation cohorts. In comparison with the previously validated PESI score, the HOPPE score had a higher discriminatory power (area under the curve 0.74 vs 0.85, p = 0.033) and significantly improved both the discrimination (integrated discrimination improvement, p = 0.002) and reclassification (net reclassification improvement, p = 0.003) of the model for short-term mortality. In conclusion, the HOPPE score accurately identifies acute patients with PE at low risk of short-term mortality, right ventricular dysfunction, and other nonfatal outcomes. Prospective validation of the prediction model is necessary before implementation in clinical practice.

Update on the risk stratification of acute symptomatic pulmonary thromboembolism

Early mortality in patients with pulmonary thromboembolism (PTE) varies from 2% in normotensive patients to 30% in patients with cardiogenic shock. The current risk stratification for symptomatic PTE includes 4 patient groups, and the recommended therapeutic strategies are based on this stratification. Patients who have haemodynamic instability are considered at high risk. Fibrinolytic treatment is recommended for these patients. In normotensive patients, risk stratification helps differentiate between those of low risk, intermediate-low risk and intermediate-high risk. There is currently insufficient evidence on the benefit of intensive monitoring and fibrinolytic treatment in patients with intermediate-high risk. For low-risk patients, standard anticoagulation is indicated. Early discharge with outpatient management may be considered, although its benefit has still not been firmly established.

Pulmonary embolism prognostic factors and length of hospital stay: A cohort study

INTRODUCTION

Patients with pulmonary embolism (PE) are commonly admitted to hospital for their initial treatment. We aimed to assess the association of length of hospital stay with commonly available clinical variables and their combinations.

METHODS

A retrospective multicenter cohort study was conducted on consecutive PE patients admitted to eight Italian centers. Logistic regression analysis was performed to evaluate the association between the length of hospital stay and the Pulmonary Embolism Severity Index (PESI) parameters, National Early Warning Score (NEWS) and other possible determinants.

RESULTS

We enrolled 391 patients, with a median hospital stay of 10days (IQR 7-14). Among PESI parameters, only oxygen saturation <90% was significantly associated with length of hospital stay at univariable analysis (OR 1.99; 95% CI 1.3-3.2). At multivariable analysis, NEWS ≥5 was associated with prolonged hospitalization (OR 3.14; 95% CI 1.2-8.3). A difference of median hospital stay was found between simplified PESI high and low risk groups (10 and 9days, respectively, p=0.027).

DISCUSSION

The median duration of hospital stay was generally long and not influenced by single parameters of PESI or common prognostic factors. The difference of one day between the low- and high-risk groups according to simplified PESI was not clinically significant.

Deep vein thrombosis and pulmonary embolism

Deep vein thrombosis and pulmonary embolism, collectively referred to as venous thromboembolism, constitute a major global burden of disease. The diagnostic work-up of suspected deep vein thrombosis or pulmonary embolism includes the sequential application of a clinical decision rule and D-dimer testing. Imaging and anticoagulation can be safely withheld in patients who are unlikely to have venous thromboembolism and have a normal D-dimer. All other patients should undergo ultrasonography in case of suspected deep vein thrombosis and CT in case of suspected pulmonary embolism. Direct oral anticoagulants are first-line treatment options for venous thromboembolism because they are associated with a lower risk of bleeding than vitamin K antagonists and are easier to use. Use of thrombolysis should be limited to pulmonary embolism associated with haemodynamic instability. Anticoagulant treatment should be continued for at least 3 months to prevent early recurrences. When venous thromboembolism is unprovoked or secondary to persistent risk factors, extended treatment beyond this period should be considered when the risk of recurrence outweighs the risk of major bleeding.

Ambulatory Versus In-Hospital Treatment of Proximal Lower-Limb Deep Vein Thrombosis in Adults: A Retrospective Cohort Study

BACKGROUND

Complications of deep vein thrombosis (DVT) are related to adequacy of initial anticoagulant therapy. In this study, we analyze consecutive patients with lower-limb proximal DVT and compare the characteristics, treatment, and clinical outcomes of patients receiving entirely ambulatory treatment versus those hospitalized for initial treatment.

METHODS

This was a retrospective study of consecutive patients with a first proximal lower-limb DVT during a 2-year period. Patients were followed for 90 days. Major end points were all-cause mortality, bleeding requiring hospitalization, and recurrent venous thromboembolism (VTE). Events were determined for patients who were hospitalized versus those treated on an entirely ambulatory basis.

RESULTS

A total of 236 patients were included in the study. Of these, 147 patients were hospitalized and 89 patients received ambulatory treatment. There were 20 fatalities-18 in-hospital and 2 in-ambulatory patients ( P = .008). By multivariable Cox regression analysis, the presence of active cancer (hazard ratio [HR] = 5.44; confidence interval [CI]: 2.16-13.7; P = .001), age (HR = 1.06; CI: 1.02-1.1; P = .001), and hospitalization (HR = 5.73; CI: 1.33-24.69; P = .019) were associated with death. Eight hospitalized and 2 ambulatory patients required readmission because of bleeding. Age was the only variable associated with bleeding (HR = 1.10; CI: 1.03-1.18; P = .004). There were no recurrent VTE events.

CONCLUSION

In this study of routine management of proximal DVT, we demonstrate that patients suitable for ambulatory care are adequately identified by physicians and may be treated with equal safety and efficacy to hospitalized patients.

Multicenter Trial of Rivaroxaban for Early Discharge of Pulmonary Embolism From the Emergency Department (MERCURY PE): Rationale and Design

OBJECTIVES

Traditionally, patients with pulmonary embolism (PE) are admitted from the emergency department and treated with low-molecular-weight heparin followed by warfarin. Several studies now demonstrate that it is possible to identify low-risk PE patients that can safely be treated as outpatients. The advent of the direct-acting oral anticoagulants such as rivaroxaban has made it easier than ever to manage patients outside of the hospital. This article describes the design of a randomized controlled trial aimed at testing the hypothesis that low-risk PE patients can be safely and effectively managed at home using rivaroxaban, resulting in fewer days of hospitalization than standard-of-care treatment.

METHODS

We have initiated a multicenter, open-label, randomized clinical trial in which low-risk adult PE patients (identified by the Hestia criteria) are randomized to outpatient management with oral rivaroxaban 15 mg twice daily for 21 days followed by 20 mg once daily for 90 days versus standard care, determined by the treating physician and based on local practices. The primary clinical endpoint will be the total number of inpatient hospital days (including the index admission) for venous thromboembolic or bleeding-related events during the first 30 days after randomization. A total of 150 subjects per group will provide 82% power to detect a difference of 1 day or greater in the primary outcome.

RESULTS

Patient enrollment is ongoing at present in 45 of 60 planned sites. No interim analysis is planned and the study is being monitored by a data safety management board.

CONCLUSIONS

The MERCURY PE study is designed to test the hypothesis that outpatient management of low-risk PE patients with rivaroxaban reduces the number of hospitalization days from venous thromboembolism and bleeding compared with standard care. This article describes the rationale and methodology for this study.

[Outpatient management of pulmonary embolism diagnosed in emergency services]

In the emergency department, the management of patients with pulmonary embolism depends on the early mortality risk. Outpatient care is possible in low-risk patients. We present the existing scores and the strategy proposed by the North Alps Emergency Network, which uses the simplified PESI score (Pulmonary Embolism Severity Index) to select those low-risk patients, candidates for early discharge.

Relationship between polycythemia and in-hospital mortality in chronic obstructive pulmonary disease patients with low-risk pulmonary embolism

BACKGROUNDS

Pulmonary embolism (PE) is frequent in subjects with chronic obstructive pulmonary disease (COPD) and associated with high mortality. This multi-center retrospective study was performed to investigate if secondary polycythemia is associated with in-hospital mortality in COPD patients with low-risk PE.

METHODS

We identified COPD patients with proven PE between October, 2005 and October, 2015. Patients in risk classes III-V on the basis of the PESI score were excluded. We extracted demographic, clinical and laboratory information at the time of admission from medical records. All subjects were followed until hospital discharge to identify all-cause mortality.

RESULTS

We enrolled 629 consecutive patients with COPD and PE at low risk: 132 of them (21.0%) with and 497 (79.0%) without secondary polycythemia. Compared with those without polycythemia, the polycythemia group had significantly lower forced expiratory volume in one second (FEV₁) level (0.9±0.3 vs. 1.4±0.5, P=0.000), lower PaO₂ and SpO₂ as well as higher PaCO₂ (P=0.03, P=0.03 and P=0.000, respectively). COPD patients with polycythemia had a higher proportion of arrhythmia in electrocardiogram (ECG) (49.5% vs. 35.7%, P=0.02), a longer hospital duration time (15.3±10.1 vs. 9.7±9.1, P=0.001), a higher mechanical ventilation rate (noninvasive and invasive, 51.7% vs. 30.3%, P=0.04 and 31.0% vs. 7.9%, P=0.04, respectively), and a higher in-hospital mortality (12.1% vs. 6.6%, P=0.04). Multivariate logistic regression analysis revealed that polycythemia was associated with mortality in COPD patients with low-risk PE (adjusted OR 1.11; 95% CI, 1.04-1.66).

CONCLUSIONS

Polycythemia is an independent risk factor for all-cause in-hospital mortality in COPD patients with PE at low risk.

Prognostic models in acute pulmonary embolism: a systematic review and meta-analysis

OBJECTIVE

To review the evidence for existing prognostic models in acute pulmonary embolism (PE) and determine how valid and useful they are for predicting patient outcomes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

OVID MEDLINE and EMBASE, and The Cochrane Library from inception to July 2014, and sources of grey literature.

ELIGIBILITY CRITERIA

Studies aiming at constructing, validating, updating or studying the impact of prognostic models to predict all-cause death, PE-related death or venous thromboembolic events up to a 3-month follow-up in patients with an acute symptomatic PE.

DATA EXTRACTION

Study characteristics and study quality using prognostic criteria. Studies were selected and data extracted by 2 reviewers.

DATA ANALYSIS

Summary estimates (95% CI) for proportion of risk groups and event rates within risk groups, and accuracy.

RESULTS

We included 71 studies (44,298 patients). Among them, 17 were model construction studies specific to PE prognosis. The most validated models were the PE Severity Index (PESI) and its simplified version (sPESI). The overall 30-day mortality rate was 2.3% (1.7% to 2.9%) in the low-risk group and 11.4% (9.9% to 13.1%) in the high-risk group for PESI (9 studies), and 1.5% (0.9% to 2.5%) in the low-risk group and 10.7% (8.8% to12.9%) in the high-risk group for sPESI (11 studies). PESI has proved clinically useful in an impact study. Shifting the cut-off or using novel and updated models specifically developed for normotensive PE improves the ability for identifying patients at lower risk for early death or adverse outcome (0.5-1%) and those at higher risk (up to 20-29% of event rate).

CONCLUSIONS

We provide evidence-based information about the validity and utility of the existing prognostic models in acute PE that may be helpful for identifying patients at low risk. Novel models seem attractive for the high-risk normotensive PE but need to be externally validated then be assessed in impact studies.

Impact of relative contraindications to home management in emergency department patients with low-risk pulmonary embolism

RATIONALE

Studies of adults presenting to the emergency department (ED) with acute pulmonary embolism (PE) suggest that those who are low risk on the PE Severity Index (classes I and II) can be managed safely without hospitalization. However, the impact of relative contraindications to home management on outcomes has not been described.

OBJECTIVES

To compare 5-day and 30-day adverse event rates among low-risk ED patients with acute PE without and with outpatient ineligibility criteria.

METHODS

We conducted a retrospective multicenter cohort study of adults presenting to the ED with acute low-risk PE between 2010 and 2012. We evaluated the association between outpatient treatment eligibility criteria based on a comprehensive list of relative contraindications and 5-day adverse events and 30-day outcomes, including major hemorrhage, recurrent venous thromboembolism, and all-cause mortality.

MEASUREMENTS AND MAIN RESULTS

Of 423 adults with acute low-risk PE, 271 (64.1%) had no relative contraindications to outpatient treatment (outpatient eligible), whereas 152 (35.9%) had at least one contraindication (outpatient ineligible). Relative contraindications were categorized as PE-related factors (n = 112; 26.5%), comorbid illness (n = 42; 9.9%), and psychosocial barriers (n = 19; 4.5%). There were no 5-day events in the outpatient-eligible group (95% upper confidence limit, 1.7%) and two events (1.3%; 95% confidence interval [CI], 0.1-5.0%) in the outpatient-ineligible group (P = 0.13). At 30 days, there were five events (two recurrent venous thromboemboli and three major bleeding events) in the outpatient-eligible group (1.8%; 95% CI, 0.7-4.4%) compared with nine in the ineligible group (5.9%; 95% CI, 2.7-10.9%; P < 0.05). This difference remained significant when controlling for PE severity class.

CONCLUSIONS

Nearly two-thirds of adults presenting to the ED with low-risk PE were potentially eligible for outpatient therapy. Relative contraindications to outpatient management were associated with an increased frequency of adverse events at 30 days among adults with low-risk PE.

Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis

OBJECTIVES

Treatment guidelines for acute pulmonary embolism (PE) recommend risk stratifying patients to assess PE severity, as those at higher risk should be considered for therapy in addition to standard anticoagulation to prevent right ventricular (RV) failure, which can cause hemodynamic collapse. The hypothesis was that 12-lead electrocardiography (ECG) can aid in this determination. The objective of this study was to measure the prognostic value of specific ECG findings (the Daniel score, which includes heart rate > 100 beats/min, presence of the S1Q3T3 pattern, incomplete and complete right bundle branch block [RBBB], and T-wave inversion in leads V1-V4, plus ST elevation in lead aVR and atrial fibrillation suggestive of RV strain from acute pulmonary hypertension), in patients with acute PE.

METHODS

Studies were identified by a structured search of MEDLINE, PubMed, EMBASE, the Cochrane library, Google Scholar, Scopus, and bibliographies in October 2014. Case reports, non-English papers, and those that lacked either patient outcomes or ECG findings were excluded. Papers with evidence of a predefined reference standard for PE and the results of 12-lead ECG, stratified by outcome (hemodynamic collapse, defined as circulatory shock requiring vasopressors or mechanical ventilation, or in hospital or death within 30 days) were included. Papers were assessed for selection and publication bias. The authors also assessed heterogeneity (I(2) ) and calculated the odds ratios (OR) for each ECG sign from the random effects model if I(2) > 24% and fixed effects if I(2) < 25%. Funnel plots were used to examine for publication bias.

RESULTS

Forty-five full-length studies of 8,209 patients were analyzed. The most frequent ECG signs found in patients with acute PE were tachycardia (38%), T-wave inversion in lead V1 (38%), and ST elevation in lead aVR (36%). Ten studies with 3,007 patients were included for full analysis. Six ECG findings (heart rate > 100 beats/min, S1Q3T3, complete RBBB, inverted T waves in V1-V4, ST elevation in aVR, and atrial fibrillation) had likelihood and ORs with lower-limit 95% confidence intervals above unity, suggesting them to be significant predictors of hemodynamic collapse and 30-day mortality. OR data showed no evidence of publication bias, but the proportions of patients with hemodynamic collapse or death and S1Q3T3 and RBBB tended to be higher in smaller studies. Patients who were outcome-negative had a significantly lower mean ± SD Daniel score (2.6 ± 1.5) than patients with hemodynamic collapse (5.9 ± 3.9; p = 0.039, ANOVA with Dunnett's post hoc), but not patients with all-cause 30-day mortality (4.9 ± 3.3; p = 0.12).

CONCLUSIONS

This systematic review and meta-analysis revealed 10 studies, including 3,007 patients with acute PE, that demonstrate that six findings of RV strain on 12-lead ECG (heart rate > 100 beats/min, S1Q3T3, complete RBBB, inverted T waves in V1-V4, ST elevation in aVR, and atrial fibrillation) are associated with increased risk of circulatory shock and death.

Cost of Treating Venous Thromboembolism With Heparin and Warfarin Versus Home Treatment With Rivaroxaban

BACKGROUND

Target-specific anticoagulants such as rivaroxaban facilitate immediate discharge of low-risk venous thromboembolism (VTE; including deep vein thrombosis [DVT] and pulmonary embolism [PE]) allowing treatment at home instead of hospitalization.

OBJECTIVES

The objective was to compare costs accrued over 6 months by patients diagnosed with low-risk VTE and treated at home with rivaroxaban versus usual care with heparin-warfarin.

METHODS

This case-control study calculated costs using the established charge-to-cost ratio from UB-04 billing claims of patients diagnosed at two metropolitan hospitals. Patients were defined as low risk by the Hestia criteria. All patients were anticoagulated for 6 months. Control patients were treated with usual care using low-molecular-weight heparin (LMWH) and then warfarin. Case patients were treated with an initial dose of rivaroxaban in the ED followed by same-day discharge home with rivaroxaban. Medians were compared by Mann-Whitney U-test.

RESULTS

Fifty cases and 47 controls were identified. Groups were well matched according to mean age, Charlson comorbidity score, and proportions by sex and location of thrombus. For all VTEs, median hospital charges for 6 months after diagnosis were $11,128 (interquartile range [IQR] = $8,110 to $23,390) for controls, compared with $4,787 (IQR = $3,042 to $7,596) for cases (Mann-Whitney U-test p < 0.001). Subgroup analyses of the first week of therapy, PE, DVT, and inpatient pharmacy costs retained significance, with costs for rivaroxaban-treated PE patients 57% lower than control PE patients (p < 0.001) and 56% lower for DVT patients (p = 0.003).

CONCLUSIONS

Cost of medical care was lower for low-risk VTE patients discharged immediately from the ED with rivaroxaban therapy compared with patients treated with LMWH-warfarin.

Pulmonary embolism: whom to discharge and whom to thrombolyze?

Patients with pulmonary embolism can be divided in two groups according to their risk of death or major complication: a small group of high-risk patients defined by the presence of systemic hypotension or cardiogenic shock and a large group of normotensive patients. Among normotensive patients, further risk stratification, based on clinical grounds alone or on the combination of clinical data, biomarkers, and imaging tests, allows selection of low-risk patients and intermediate-risk patients. The safety of outpatient treatment for low-risk patients has been established mainly on the basis of retrospective and prospective cohorts using different selection tools. In most studies, about 50% of the patients have been safely treated at home. Although thrombolytic therapy has a favorable benefit to risk profile in patients with high-risk pulmonary embolism, the risk of major and especially intracranial bleeding outweighs the benefits in terms of hemodynamic decompensation in patients with intermediate-risk pulmonary embolism.

Rate and duration of hospitalization for deep vein thrombosis and pulmonary embolism in real-world clinical practice

BACKGROUND

Current guidelines recommend initial treatment with anticoagulants at home in patients with acute deep vein thrombosis (DVT) and in patients with low-risk pulmonary embolism (PE) with adequate home circumstances. However, most of the patients with acute venous thromboembolism (VTE) are currently hospitalized regardless of their risk of short-term complications.

AIM OF THE STUDY

To assess the proportion of outpatients with acute VTE initially treated in hospitals, to assess the mean duration of hospitalization, and to identify predictors for in-hospital or home treatment.

METHODS

Data of Italian patients enrolled in the RIETE registry from January 2006 to December 2013 were included.

RESULTS

Altogether 766 PE and 1,452 isolated DVT were included. Among PE patients, mean PESI score was 84 points (SD 35), and 56% of patients had a low-risk PESI score (<85). In all, 53.7% of DVT and 17.0% of PE were entirely treated at home, and 38.2% of DVT patients and 19.9% of PE patients were hospitalized for ≤5 days. On multivariate analysis, low PESI score was not independently associated with the hospitalization of PE patients.

CONCLUSIONS

One in every two patients with DVT and five in every six with PE are still hospitalized.

Systematic review and meta-analysis of pregnant patients investigated for suspected pulmonary embolism in the emergency department

OBJECTIVES

Pregnancy causes a small increase in risk of venous thromboembolism (VTE), but a large increase in concern upon presentation to an emergency department (ED) with symptoms of pulmonary embolism (PE), which may cause physicians to employ a low test threshold. This was a systematic review with the hypothesis that symptomatic pregnant patients in the ED have a low relative risk (RR) for VTE outcome.

METHODS

Studies in all languages were identified by structured search of PubMed, EMBASE, the Cochrane library, and bibliographies in February 2014. Papers with ED patients evaluated for possible PE that included pregnancy status, and had adequate reference standards, were included. An outcome of VTE (either deep venous thrombosis [DVT] or PE) was considered disease-positive (VTE+). Papers were assessed for selection and publication bias, and heterogeneity (I(2) ). The random effects model was used if I(2)  > 24%.

RESULTS

Seventeen full-length studies of 25,339 patients were analyzed. Pooled data showed I² = 0% with a symmetrical funnel plot. Two small studies with less than 1% of all patients had evidence of selection bias. The frequency of VTE+ rate among the 506 pregnant patients was 4.1% (95% confidence interval [CI] = 2.6% to 6.0%), compared with 12.4% (95% CI = 9.0% to 16.3%) among nonpregnant patients. The pooled RR of pregnancy for VTE+ diagnosis was 0.60 (95% CI = 0.41 to 0.87). Patients in the third trimester had a RR of 0.85 (95% CI = 0.40 to 1.77), and patients of childbearing age (≤45 years) had a RR of 0.56 (95% CI = 0.34 to 0.93).

CONCLUSIONS

In the ED setting, physicians test for PE in pregnant patients at a low threshold, resulting in a low rate of VTE diagnosis and a RR of VTE that is lower than that for nonpregnant women of childbearing age who are tested for PE in the ED setting.

Pulmonary embolism severity index accurately predicts long-term mortality rate in patients hospitalized for acute pulmonary embolism

BACKGROUND

The Pulmonary Embolism (PE) Severity Index (PESI) is a clinical prognostic rule that accurately classifies PE patients into five risk classes with increasing mortality. PESI score has been validated in studies with a relatively short-term follow-up and its accuracy in predicting long-term prognosis has never been established.

METHODS

Consecutive patients admitted to the tertiary care hospital of Varese (Italy) with an objectively diagnosed PE between January 2005 and December 2009 were retrospectively included. Information on clinical presentation, diagnostic work-up, risk factors, treatment and mortality during a 1-year follow-up was collected.

RESULTS

Five hundred and thirty-eight patients were enrolled in this study. The mean age was 70.6 years (± SD 15.2), 44.4% of patients were male, and 27.9% had known cancer. One-year follow-up was available for 96.1% of patients. The overall mortality rate was 23.2% at 3 months, 30.2% at 6 months and 37.1% at 12 months. The discriminatory power of the PESI score to predict long-term mortality, expressed as the area under the ROC curve, was 0.77 (95%CI, 0.72-0.81) at 3 months, 0.77 (95%CI, 0.73-0.81) at 6 months and 0.79 (95%CI, 0.75-0.82) at 12 months. The PESI score confirmed its accurate prediction in patients without cancer. Simplified PESI had a similar overall accuracy to the original PESI at 3 and 6 months, but this was significantly lower at 1 year.

CONCLUSIONS

The results of this study suggest that PESI score may also be an accurate tool to define the 6-month and 1-year mortality rates in PE patients.

New prospective for the management of low-risk pulmonary embolism: prognostic assessment, early discharge, and single-drug therapy with new oral anticoagulants

Patients with pulmonary embolism (PE) can be stratified into two different prognostic categories, based on the presence or absence of shock or sustained arterial hypotension. Some patients with normotensive PE have a low risk of early mortality, defined as <1% at 30 days or during hospital stay. In this paper, we will discuss the new prospective for the optimal management of low-risk PE: prognostic assessment, early discharge, and single-drug therapy with new oral anticoagulants. Several parameters have been proposed and investigated to identify low-risk PE: clinical prediction rules, imaging tests, and laboratory markers of right ventricular dysfunction or injury. Moreover, outpatient management has been suggested for low-risk PE: it may lead to a decrease in unnecessary hospitalizations, acquired infections, death, and costs and to an improvement in health-related quality of life. Finally, the main characteristics of new oral anticoagulant drugs and the most recent published data on phase III trials on PE suggest that the single-drug therapy is a possible suitable option. Oral administration, predictable anticoagulant responses, and few drug-drug interactions of direct thrombin and factor Xa inhibitors may further simplify PE home therapy avoiding administration of low-molecular-weight heparin.