Factors associated with clinical deterioration shortly after PE

Impact of coincident lower extremity deep vein thrombosis on symptomatic and incidental pulmonary embolism outcomes. A single-center prospective cohort study

BACKGROUND

The prognostic implications of co-incident DVT at the time of PE diagnosis remains unclear.

OBJECTIVES

Study aims were to assess the impact of co-incident lower extremity (LE) deep vein thrombosis (DVT) on clinical outcomes of pulmonary embolism (PE) including venous thromboembolism (VTE) recurrence and mortality.

METHODS

Consecutive patients with confirmed acute symptomatic or incidental PE (March 1, 2013 to June 30, 2021) who underwent ultrasound imaging were divided into two groups depending on the presence or absence of LE DVT. Patients were followed prospectively for VTE recurrence, bleeding, and all-cause mortality.

RESULTS

Over the study period, 1907 patients with PE were stratified into groups based on the presence (n = 920) or absence (n = 987) of LE DVT. Patients with co-incident LE DVT were older, heavier, and had a significantly greater frequency of trauma, confinement, thrombophilia, and VTE. Those without LE DVT had a higher prevalence of active cancer, metastatic disease, and active systemic therapy use. All-cause mortality rates (per 100 person-years) were significantly higher for patients without vs with co-incident LE DVT (42.4/100 person-years vs 29.6/100 person- years; P < .001) with no differences in VTE recurrence or bleeding outcomes. After stratification by cancer status, mortality in those without vs. with co-incident DVT only remained significant among noncancer patients (15.2/100 person-years vs 12.1/100 person-years, P = .046).

CONCLUSIONS

Among patients with acute PE, the absence of co-incident lower extremity DVT is associated with significantly higher mortality rates. Mortality rate differences were only observed for those without cancer. No differences in VTE recurrence or bleeding were observed.

Prevalence and clinical significance of deep vein thrombosis in Hispanic patients with acute pulmonary embolism

The prevalence of concomitant deep vein thrombosis (DVT) and its impact on 30-day outcomes in Hispanic patients with acute pulmonary embolism (PE) is unknown. We retrospectively studied a cohort of Hispanic patients admitted for acute PE to determine the relationship of concomitant DVT to clot burden on chest computer tomography (CT), right heart strain, and 30-day mortality. We identified 391 patients admitted with acute PE; 168 (42.9%) had concomitant DVTs on admission; 39 patients (9.9%) died during the 30-day follow-up: 12 patients without concomitant DVT and 27 with concomitant DVT, respectively (p < .001). The presence of a proximal DVT independently predicted 30-day mortality even after adjusting for age, gender and admission PE severity index scores (PESI) (hazard ratio [HR] 2.0; 95% confidence interval [CI]: 1.4-3.0, p = .001). Proximal DVTs remained a significant predictor of 30-day mortality in patients with low and intermediate PESI scores (HR 2.5; 95% CI: 1.1-6.0, p = .035). The prevalence of concomitant DVT in Hispanic patients presenting with acute DVT is relatively lower than other ethnic groups. However, a proximal location of a DVT is of significant prognostic relevance. Hispanic patients with acute PE should routinely undergo compression doppler ultrasonography (CDUS) of the lower extremities.

Intubation and Mechanical Ventilation in Patients with Acute Pulmonary Embolism: A Scoping Review

OBJECTIVES

High-risk acute pulmonary embolism (PE) is associated with significant mortality and may require emergency endotracheal intubation and mechanical ventilation. Intubation and ventilation are thought to exacerbate cardiorespiratory instability. Our purpose was to conduct a systematic literature review to identify studies investigating peri-intubation events in acute PE.

METHODS

A systematic search of Medline, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library was performed. Results were screened by two independent observers. Studies reporting on intubation and positive pressure ventilation in acute PE patients were included. The primary outcome was adverse events during the peri-intubation period. Data was synthesized and an assessment of risk of bias was conducted. The review was registered on PROSPERO (CRD42023444483).

RESULTS

4100 unique articles were screened. Three retrospective studies comprising 104 patients with acute PE met criteria and were included. Peri-intubation, hemodynamic collapse was observed in 19%-28% of cases. Patients with hemodynamic collapse exhibited higher rates of echocardiographic RV dysfunction.

CONCLUSIONS

Peri-intubation adverse events are common in patients with acute PE. Current evidence is limited and highlights the need for further research to optimize management of respiratory failure in acute PE and patient selection for intubation to improve patient outcomes.

Low concordance between CTPA and echocardiography in identification of right ventricular strain in PERT patients with acute pulmonary embolism

PURPOSE

Right ventricular strain (RVS) is used to risk stratify patients with acute pulmonary embolism (PE) and influence treatment decisions. Guidelines suggest that either computed tomography pulmonary angiography (CTPA) or transthoracic echocardiography (TTE) can be used to assess RVS. We sought to determine how often CTPA and TTE yield discordant results and to assess the test characteristics of CTPA compared to TTE.

METHODS

We analyzed data from a single-center registry of PE cases severe enough to warrant activation of the hospital's Pulmonary Embolism Response Team (PERT). We defined RVS as a right ventricular to left ventricular ratio (RV/LV) ≥ 1 or radiologist's interpretation of RVS on CTPA or as the presence of either RV dilation, hypokinesis, or septal bowing on TTE.

RESULTS

We included 554 patients in our analysis, of whom 333 (60%) had concordant RVS findings on CTPA and TTE. Using TTE as the reference standard, CTPA had a sensitivity of 95% (95% CI 92-97%) and a specificity of 4% (95% CI 2-8%) for identifying RVS.

CONCLUSIONS

In a selected population of patients with acute PE for which PERT was activated, CTPA is highly sensitive but not specific for the detection of RVS when compared to TTE.

Pulmonary Embolism in the Cancer Associated Thrombosis Landscape

In cancer patients, pulmonary embolism (PE) is the second leading cause of death after the cancer itself, most likely because of difficulties in diagnosing the disease due to its nonclassical presentation. The risk of PE recurrence and possibly the case-fatality rate depends on whether the patient presents a symptomatic PE, an unsuspected PE, a subsegmental PE, or a catheter-related PE. Choosing the best therapeutic option is challenging and should consider the risk of both the recurrence of thrombosis and the occurrence of bleeding. The purpose of this review is to provide an overview of the clinical characteristics and the treatment of cancer-associated PE, which could benefit clinicians to better manage the deadliest form of thrombosis associated with cancer. After a brief presentation of the epidemiological data, we will present the current attitude towards the diagnosis and the management of cancer patients with PE. Finally, we will discuss the perspectives of how the medical community can improve the management of this severe medical condition.

Evaluating cardiopulmonary function following acute pulmonary embolism

INTRODUCTION

Pulmonary embolism is a common cause of cardiopulmonary mortality and morbidity worldwide. Survivors of acute pulmonary embolism may experience dyspnea, report reduced exercise capacity, or develop overt pulmonary hypertension. Clinicians must be alert for these phenomena and appreciate the modalities and investigations available for evaluation.

AREAS COVERED

In this review, the current understanding of available contemporary imaging and physiologic modalities is discussed, based on available literature and professional society guidelines. The purpose of the review is to provide clinicians with an overview of these modalities, their strengths and disadvantages, and how and when these investigations can support the clinical work-up of patients post-pulmonary embolism.

EXPERT OPINION

Echocardiography is a first test in symptomatic patients post-pulmonary embolism, with ventilation/perfusion scanning vital to determination of whether there is chronic residual emboli. The role of computed tomography and magnetic resonance in assessing the pulmonary arterial tree in post-pulmonary embolism patients is evolving. Functional testing, in particular cardiopulmonary exercise testing, is emerging as an important modality to quantify and determine cause of functional limitation. It is possible that future investigations of the post-pulmonary embolism recovery period will better inform treatment decisions for acute pulmonary embolism patients.

Can right ventricular assessments improve triaging of low risk pulmonary embolism?

OBJECTIVES

Identifying right ventricle (RV) abnormalities is important to stratifying pulmonary embolism (PE) severity. Disposition decisions are influenced by concerns about early deterioration. Triaging strategies, like the Simplified Pulmonary Embolism Severity Index (sPESI), do not include RV assessments as predictors or early deterioration as outcome(s). We aimed to (1) determine if RV assessment variables add prognostic accuracy for 5-day clinical deterioration in patients classified low risk by sPESI, and (2) determine the prognostic importance of RV assessments compared to other variables and to each other.

METHODS

We identified low risk sPESI patients (sPESI = 0) from a prospective PE registry. From a large field of candidate variables, we developed, and compared prognostic accuracy of, full and reduced random forest models (with and without RV assessment variables, respectively) on a validation database. We reported variable importance plots from full random forest and provided odds ratios for statistical inference of importance from multivariable logistic regression. Outcomes were death, cardiac arrest, hypotension, dysrhythmia, or respiratory failure within 5 days of PE.

RESULTS

Of 1736 patients, 610 (35.1%) were low risk by sPESI and 72 (11.8%) experienced early deterioration. Of the 610, RV abnormality was present in 157 (25.7%) by CT, 121 (19.8%) by echocardiography, 132 (21.6%) by natriuretic peptide, and 107 (17.5%) by troponin. For deterioration, the receiver operating characteristics for full and reduced random forest prognostic models were 0.80 (0.77-0.82) and 0.71 (0.68-0.73), respectively. RV assessments were the top four in the variable importance plot for the random forest model. Echocardiography and CT significantly increased predicted probability of 5-day clinical deterioration by the multivariable logistic regression.

CONCLUSIONS

A PE triaging strategy with RV imaging assessments had superior prognostic performance at classifying low risk for 5-day clinical deterioration versus one without.

A clinical decision framework to guide the outpatient treatment of emergency department patients diagnosed with acute pulmonary embolism or deep vein thrombosis: Results from a multidisciplinary consensus panel

The outpatient treatment of select emergency department patients with acute pulmonary embolism (PE) or deep vein thrombosis (DVT) has been shown to be safe, cost effective and associated with high patient satisfaction. Despite this, outpatient PE and DVT treatment remains uncommon. To address this, the American College of Emergency Physicians assembled a multidisciplinary team of content experts to provide evidence-based recommendations and practical advice to help clinicians safely treat patients with low-risk PE and DVT without hospitalization. The emergency clinician must stratify the patient's risk of clinical decompensation due to their PE or DVT as well as their risk of bleeding due to anticoagulation. The clinician must also select and start an anticoagulant and ensure that the patient has access to the medication in a timely manner. Reliable follow-up is critical, and the patient must also be educated about signs or symptoms that should prompt a return to the emergency department. To facilitate access to these recommendations, the consensus panel also created 2 web-based "point-of-care tools."

Development and validation of a prognostic tool: Pulmonary embolism short-term clinical outcomes risk estimation (PE-SCORE)

OBJECTIVE

Develop and validate a prognostic model for clinical deterioration or death within days of pulmonary embolism (PE) diagnosis using point-of-care criteria.

METHODS

We used prospective registry data from six emergency departments. The primary composite outcome was death or deterioration (respiratory failure, cardiac arrest, new dysrhythmia, sustained hypotension, and rescue reperfusion intervention) within 5 days. Candidate predictors included laboratory and imaging right ventricle (RV) assessments. The prognostic model was developed from 935 PE patients. Univariable analysis of 138 candidate variables was followed by penalized and standard logistic regression on 26 retained variables, and then tested with a validation database (N = 801).

RESULTS

Logistic regression yielded a nine-variable model, then simplified to a nine-point tool (PE-SCORE): one point each for abnormal RV by echocardiography, abnormal RV by computed tomography, systolic blood pressure < 100 mmHg, dysrhythmia, suspected/confirmed systemic infection, syncope, medico-social admission reason, abnormal heart rate, and two points for creatinine greater than 2.0 mg/dL. In the development database, 22.4% had the primary outcome. Prognostic accuracy of logistic regression model versus PE-SCORE model: 0.83 (0.80, 0.86) vs. 0.78 (0.75, 0.82) using area under the curve (AUC) and 0.61 (0.57, 0.64) vs. 0.50 (0.39, 0.60) using precision-recall curve (AUCpr). In the validation database, 26.6% had the primary outcome. PE-SCORE had AUC 0.77 (0.73, 0.81) and AUCpr 0.63 (0.43, 0.81). As points increased, outcome proportions increased: a score of zero had 2% outcome, whereas scores of six and above had ≥ 69.6% outcomes. In the validation dataset, PE-SCORE zero had 8% outcome [no deaths], whereas all patients with PE-SCORE of six and above had the primary outcome.

CONCLUSIONS

PE-SCORE model identifies PE patients at low- and high-risk for deterioration and may help guide decisions about early outpatient management versus need for hospital-based monitoring.

Predicting factors for pulmonary embolism response team activation in a general pulmonary embolism population

Pulmonary embolism response teams (PERT) aim to improve treatment of acute pulmonary embolism (PE). PERT focus on intermediate- and high-risk PE patients, but recent multicenter studies show that low-risk PE patients compose one in five of all PERT cases. Conversely, not all intermediate- and high-risk PE patients elicit a PERT activation. The factors leading to PERT activations remain unknown. This study aims to describe the patient characteristics associated with PERT activation for low-risk PE patients and characteristics precluding PERT activation for intermediate/high-risk PE patients. We analysed data from all patients with confirmed PE diagnosed in the Massachusetts General Hospital Emergency Department from August 2013 to February 2017 and cross-referred these data with patients who received a PERT activation and patients who did not. Patients were stratified into low-risk or intermediate/high-risk PE. Univariate analyses were performed within each risk group comparing patients with a PERT activation and patients without. Fifteen percent (56/374) of low-risk PE patients triggered a PERT activation. Patient characteristics associated with PERT activation were: (1) vascular disease, (2) pulmonary diseases, (3) thrombophilia, (4) current use of anticoagulants, (5) central PE and (6) concurrent DVT. Thirty-five percent (110/283) of intermediate/high-risk PE patients did not elicit a PERT activation. Patient characteristics precluding a PERT activation were: (1) vascular disease, (2) malignancies and (3) asymptomatic presentation. Low-risk PE patients with PERT activations had more extensive clot burden, complex comorbidities, or had failed anticoagulation treatment. Intermediate/high-risk PE patients without PERT activations tended to have malignancies or vascular disease.

The echocardiographic ratio tricuspid annular plane systolic excursion/pulmonary arterial systolic pressure predicts short-term adverse outcomes in acute pulmonary embolism

AIMS

Right ventricular (RV) failure causes death from acute pulmonary embolism (PE), due to a mismatch between RV systolic function and increased RV afterload. We hypothesized that an echocardiographic ratio of this mismatch [RV systolic function by tricuspid annular plane systolic excursion (TAPSE) divided by pulmonary arterial systolic pressure (PASP)] would predict adverse outcomes better than each measurement individually, and would be useful for risk stratification in intermediate-risk PE.

METHODS AND RESULTS

This was a retrospective analysis of a single academic centre Pulmonary Embolism Response Team registry from 2012 to 2019. All patients with confirmed PE and a formal transthoracic echocardiogram performed within 2 days were included. All echocardiograms were analysed by an observer blinded to the outcome. The primary endpoint was a 7-day composite outcome of death or haemodynamic deterioration. Secondary outcomes were 7- and 30-day all-cause mortality. A total of 627 patients were included; 135 met the primary composite outcome. In univariate analysis, the TAPSE/PASP was associated with our primary outcome [odds ratio = 0.028, 95% confidence interval (CI) 0.010-0.087; P < 0.0001], which was significantly better than either TAPSE or PASP alone (P = 0.017 and P < 0.0001, respectively). A TAPSE/PASP cut-off value of 0.4 was identified as the optimal value for predicting adverse outcome in PE. TAPSE/PASP predicted both 7- and 30-day all-cause mortality, while TAPSE and PASP did not.

CONCLUSION

A combined echocardiographic ratio of RV function to afterload is superior in prediction of adverse outcome in acute intermediate-risk PE. This ratio may improve risk stratification and identification of the patients that will suffer short-term deterioration after intermediate-risk PE.

Inhaled nitric oxide has pulmonary vasodilator efficacy both in the immediate and prolonged phase of acute pulmonary embolism

BACKGROUND

Inhaled nitric oxide (iNO) effectively reduces right ventricular afterload when administered in the immediate phase of acute pulmonary embolism (PE) in preclinical animal models. In a porcine model of intermediate-risk PE, we aimed to investigate whether iNO has pulmonary vasodilator efficacy both in the immediate and prolonged phase of acute PE.

METHODS

Anesthetized pigs (n = 18) were randomized into three subgroups. An acute PE iNO-group (n = 6) received iNO at 40 ppm at one, three, six, nine and 12 hours after onset of PE. Vehicle animals (n = 6) received PE, but no active treatment. A third group of sham animals (n = 6) received neither PE nor treatment. Animals were evaluated using intravascular pressures, respiratory parameters, biochemistry and intracardiac pressure-volume measurements.

RESULTS

The administration of PE increased mean pulmonary artery pressure (mPAP) (vehicle vs sham; 33.3 vs 17.7 mmHg, p < 0.0001), pulmonary vascular resistance (vehicle vs sham; 847.5 vs 82.0 dynes, p < 0.0001) and right ventricular arterial elastance (vehicle vs sham; 1.2 vs 0.2 mmHg/ml, p < 0.0001). Significant mPAP reduction by iNO was preserved at 12 hours after the onset of acute PE (vehicle vs iNO; 0.5 vs -3.5 mmHg, p < 0.0001). However, this response was attenuated over time (p = 0.0313). iNO did not affect the systemic circulation.

CONCLUSIONS

iNO is a safe and effective pulmonary vasodilator both in the immediate and prolonged phase of acute PE in an in-vivo porcine model of intermediate-risk PE.

Rapid prediction of adverse outcomes for acute normotensive pulmonary embolism: derivation of the Calgary Acute Pulmonary Embolism score

Background

Acute pulmonary embolism (PE) has a wide spectrum of outcomes, but the best method to risk-stratify normotensive patients for adverse outcomes remains unclear.

Methods

A multicentre retrospective cohort study of acute PE patients admitted from emergency departments in Calgary, Canada, between 2012 and 2017 was used to develop a refined acute PE risk score. The composite primary outcome of in-hospital PE-related death or haemodynamic decompensation. The model was internally validated using bootstrapping and the prognostic value of the derived risk score was compared to the Bova score.

Results

Of 2067 patients with normotensive acute PE, the primary outcome (haemodynamic decompensation or PE-related death) occurred in 32 (1.5%) patients. In simplified Pulmonary Embolism Severity Index high-risk patients (n=1498, 78%), a multivariable model used to predict the primary outcome retained computed tomography (CT) right–left ventricular diameter ratio ≥1.5, systolic blood pressure 90–100 mmHg, central pulmonary artery clot and heart rate ≥100 beats·min⁻¹ with a C-statistic of 0.89 (95% CI 0.82–0.93). Three risk groups were derived using a weighted score (score, prevalence, primary outcome event rate): group 1 (0–3, 73.8%, 0.34%), group 2 (4–6, 17.6%, 5.8%), group 3 (7–9, 8.7%, 12.8%) with a C-statistic 0.85 (95% CI 0.78–0.91). In comparison the prevalence (primary outcome) by Bova risk stages (n=1179) were stage I 49.8% (0.2%); stage II 31.9% (2.7%); and stage III 18.4% (7.8%) with a C-statistic 0.80 (95% CI 0.74–0.86).

Conclusions

A simple four-variable risk score using clinical data immediately available after CT diagnosis of acute PE predicts in-hospital adverse outcomes. External validation of the Calgary Acute Pulmonary Embolism score is required.

Derivation of a simple four-variable risk score that uses parameters available at the time of PE diagnosis to risk stratify acute normotensive PE patients, which may help clinicians better decide how to monitor and treat patientshttps://bit.ly/37PdyrM

Oxygen Therapy Lowers Right Ventricular Afterload in Experimental Acute Pulmonary Embolism

OBJECTIVES

To investigate if oxygen could unload the right ventricle and improve right ventricle function in a porcine model mimicking intermediate-high risk acute pulmonary embolism.

DESIGN

Controlled, blinded, animal study.

SETTING

Tertiary university hospital, animal research laboratory.

SUBJECTS

Female, Danish pigs (n = 16, approximately 60 kg).

INTERVENTIONS

Acute autologous pulmonary embolism was induced until doubling of baseline mean pulmonary arterial pressure. Group 1 animals (n = 8) received increasing Fio2 (40%, 60%, and 100%) for time intervals of 15 minutes returning to atmospheric air between each level of Fio2. In group 2 (n = 8), the effects of Fio2 40% maintained over 75 minutes were studied. In both groups, pulmonary vasodilatation from inhaled nitric oxide (40 parts per million) was used as a positive control.

MEASUREMENTS AND MAIN RESULTS

Effects were evaluated by biventricular pressure-volume loop recordings, right heart catheterization, and arterial and mixed venous blood gasses. Pulmonary embolism increased mean pulmonary arterial pressure from 15 ± 4 to 33 ± 6 mm Hg (p = 0.0002) and caused right ventricle dysfunction (p < 0.05) with troponin release (p < 0.0001). In group 1, increasing Fio2 lowered mean pulmonary arterial pressure (p < 0.0001) and pulmonary vascular resistance (p = 0.0056) and decreased right ventricle volumes (p = 0.0018) and right ventricle mechanical work (p = 0.034). Oxygenation was improved and pulmonary shunt was lowered (p < 0.0001). Maximal hemodynamic effects were seen at Fio2 40% with no additional benefit from higher fractions of oxygen. In group 2, the effects of Fio2 40% were persistent over 75 minutes. Supplemental oxygen showed the same pulmonary vasodilator efficacy as inhaled nitric oxide (40 parts per million). No adverse effects were observed.

CONCLUSIONS

In a porcine model mimicking intermediate-high risk pulmonary embolism, oxygen therapy reduced right ventricle afterload and lowered right ventricle mechanical work. The effects were immediately present and persistent and were similar to inhaled nitric oxide. The intervention is easy and safe. The study motivates extended clinical evaluation of supplemental oxygen in acute pulmonary embolism.

Validation of the 2019 European Society of Cardiology Risk Stratification Algorithm for Pulmonary Embolism in Normotensive Elderly Patients

BACKGROUND

 The 2019 European Society of Cardiology (ESC) guidelines recommend evaluation for right ventricular dysfunction in all normotensive patients with acute pulmonary embolism (PE). We compared the predictive performance of the 2019 and 2014 ESC risk stratification algorithms and the Pulmonary Embolism Severity Index (PESI).

METHODS

 We performed a posthoc analysis of normotensive patients aged ≥ 65 years with acute PE from a prospective cohort. The primary outcome was overall mortality; secondary outcomes were PE-related mortality and adverse outcomes (PE-related death, cardiopulmonary resuscitation, intubation, catecholamine use, recurrent venous thromboembolism) at 30 days. We assessed outcomes in intermediate-high, intermediate-low, and low-risk groups according to the 2019 and 2014 ESC algorithms and the PESI. Discriminative power was compared using the area under the receiver operating characteristic curve (AUC).

RESULTS

 Among 419 patients, 14 (3.3%) died (7 from PE) and 16 (3.8%) had adverse outcomes within 30 days. The 2019 ESC algorithm classified more patients as intermediate-high risk (45%) than the 2014 ESC algorithm (24%) or the PESI (37%), and only 19% as low risk (32% with 2014 ESC or the PESI). Discriminatory power for overall mortality was lower with the 2019 ESC algorithm (AUC: 63.6%), compared with the 2014 ESC algorithm (AUC: 71.5%) or the PESI (AUC: 75.2%), although the difference did not reach statistical significance (p = 0.063). Discrimination for PE-related mortality and adverse outcomes was similar.

CONCLUSION

 While categorizing more patients in higher risk groups, the 2019 ESC algorithm for PE did not improve prediction of short-term outcomes compared with the 2014 ESC algorithm or the PESI.

Clinical factors associated with massive pulmonary embolism and PE-related adverse clinical events

Background

Clinicians evaluating acute PE patients often have to identify risks for massive PE, a measure of hemodynamic instability and its consequence, massive PE related adverse clinical events (PEACE). We investigated the association of these risk factors with massive PE and PEACE in a consecutive PE cohort (n = 364).

Methods

Massive PE was defined as an acute central clot (proximal to the lobar artery) in a patient with right heart strain and systolic blood pressure ≤ 90 mg. PEACE was defined as any massive PE who died or required one or more of the following: ACLS, assisted ventilation, vasopressor use, thrombolytic therapy, or invasive thrombectomy, within seven days of PE diagnosis. Univariate and multivariate analysis assessing associations between the risk factors (age, gender, comorbidities, PE provoking risks, and whether the PE was felt to be idiopathic) and massive PE or PEACE were performed. Significance was determined at p < 0.05.

Results

Thirteen percent (n = 48) of patients presented with massive PE, and 9% (n = 32) had PEACE. In the final multivariate model, recent invasive procedure (RR = 7.4, p = 0.007), recent hospitalization (RR = 7.3, p = 0.002), and idiopathic PE (RR = 6.5, p = 0.003) were associated with massive PE. Only idiopathic PE (RR = 5.7, p = 0.005) was significantly associated with PEACE. No comorbidities or other PE provoking risks were associated with massive PE or PEACE.

Conclusions

As a take-home message, recent invasive procedure, recent hospitalization, and idiopathic PE were associated with massive PE, and only idiopathic PE was associated with PEACE. Simultaneously, comorbidities like age or chronic cardiopulmonary disease seem not to be associated with massive PE or PEACE.

Prediction of Mortality Associated with Cardiac and Radiological Findings in Patients with Pulmonary Embolism

Background: In this study, we aimed to compare echocardiography, electrocardiography (ECG) abnormalities, Doppler ultrasonography (USG), and computed tomography pulmonary angiography (CTPA) results in predicting 3-month mortality in patients with acute pulmonary embolism (PE).

Methods: This retrospective cohort study included 124 patients (72 females, 52 males) with acute PE. Demographics, symptoms, clinical signs, comorbidities, history of surgery, arterial blood gas, liver-renal functions, complete blood count, echocardiography, ECG, Doppler USG, and CTPA results, as well as 3-month mortality were recorded.

Results: pH (z = –2.623; p <0.01), hemoglobin (z = –3.112; p <0.01), and oxygen saturation (z = –2.165; p <0. 01) were significantly higher in survivors. White blood cell (z = –2.703; p <0.01), blood urea nitrogen (z = –3.840; p <0.01), creatinine (z = –3.200; p <0.01), respiratory rate (z = –2.759; p <0.01), and heart rate (z = –2.313; p <0.01) were significantly higher in non-survivors. Nonspecific ST changes (AUC 0.52, 95% CI 0.43–0.61), p pulmonale (AUC 0.52, 95% CI 0.43–0.61), normal axis (AUC 0.61), right axis deviation (AUC 0.56), right ventricle strain pattern (AUC 0.59), and right pulmonary artery embolism (AUC 0.54) on CTPA showed the highest mortality prediction.

Conclusions: Nonspecific ST changes, p pulmonale, normal axis and right axis deviation in ECG, RV strain in echocardiography, and right pulmonary artery embolism on CTPA are associated with a higher mortality in patients with PE.

Patient and operational factors that influence the decision to place an inferior vena cava filter in a pulmonary embolism response team

OBJECTIVE

The use of inferior vena cava (IVC) filters is controversial. However, the procedure is widely performed for secondary prophylaxis in patients with severe pulmonary embolism (PE), including those treated by a PE response team (PERT). In this study, we analyzed patient factors associated with the clinical decision to place an IVC filter in PERT patients.

METHODS

Data were collected on all Massachusetts General Hospital patients who had a PERT activation from October 1, 2012, to January 29, 2019. Data describing demographics, medical history, PE characteristics and treatment were collected at the time of PERT activation and prospectively for one year after PERT activation. Univariate and multivariable regression analyses were performed to determine factors associated with IVC filter placement.

RESULTS

We identified 834 patients, of whom 91 (10.9%) had an IVC filter placed in the first 7 days after PERT activation. The majority of patients receiving an IVC filter were male (55/91 [60.4%]; P =.096) with a mean age of 65 ± 15.0 years. Patients who received an IVC filter were less likely to have had a PERT referral from the Emergency Department (ED) (41/544 [7.5%]; P < .001) and more likely to have been referred from the intensive care unit (24/107 [22.43%]; P ≤ .001) compared with a floor referral. Patients who presented with syncope (15/86 [17.4%]; P = .040), a history of recent trauma (12/41 [29.3%]; P < .001), intracranial hemorrhage (11/39 [28.2%]; P = .002), a recent surgery or invasive procedure (30/188 [16.0%]; P = .012), a recent surgery (29/160 [18.1%]; P = .001) and a recent hospitalization (38/250 [15.2%]; P = .009) were more likely to have an IVC filter placed. Patients receiving an IVC filter were also more likely to have evidence of right heart dysfunction on a computed tomography pulmonary angiogram (61/359 [17.0%]; P < .001) and an echocardiogram (26/144 [18.1%]; P = .003). Compared with patients without an IVC filter, the 30-day venous thromboembolism recurrence rate was higher (4.7% vs 11.0%) in patients with IVC filters (10/45 [22.2%]; P = .023).

CONCLUSIONS

Factors associated with venous thromboembolism severity (eg, PERT referral from intensive care unit and right ventricular dysfunction) and an increased bleeding risk (eg, recent surgery or trauma) were associated with IVC filter placement among PERT patients.

Impact of no, distal, and proximal deep vein thrombosis on clinical outcomes in patients with acute pulmonary embolism: From the COMMAND VTE registry

BACKGROUND

The majority of acute pulmonary embolism (PE) is caused by thrombus developed from leg veins. However, impact of concomitant deep venous thrombosis (DVT) on clinical outcomes has not been fully evaluated in patients with acute PE.

METHODS

The COMMAND VTE Registry is a multicenter registry enrolling consecutive 3027 patients with acute symptomatic venous thromboembolism (VTE) in Japan. The current study population consisted of 655 acute PE patients who underwent lower extremities ultrasound examination at diagnosis for the assessment of concomitant DVT status.

RESULTS

There were 424 patients with proximal DVT (64.7%), 162 patients with distal DVT (24.7%), and 69 patients with no DVT (10.5%). The cumulative 90-day incidence of all-cause death was higher in proximal DVT patients than in distal DVT and no DVT patients (7.9%, 2.5%, and 1.4%, p = 0.01). Regarding the causes of death, the cumulative 90-day incidence of PE-related death was low, and not significantly different across the 3 groups (1.4%, 0.6%, and 1.7%, p = 0.62). The most frequent cause of death was cancer in proximal and distal DVT patients. There were no significant differences in 90-day rates of recurrent VTE and major bleeding, regardless of the status of concomitant DVT (2.9%, 3.2%, and 2.2%, p = 0.79, and 1.5%, 4.4%, and 4.9%, p = 0.46, respectively).

CONCLUSIONS

Acute PE with proximal DVT at diagnosis was associated with a higher risk for short-term mortality than in patients without DVT, while the risk for short-term mortality was not significantly different between distal DVT patients and patients without DVT.

Prognostic Significance of Incidental Deep Vein Thrombosis in Patients with Cancer Presenting with Incidental Pulmonary Embolism

In symptomatic acute pulmonary embolism (PE), the presence of deep vein thrombosis (DVT) is a risk factor for 30- and 90-day mortality. In patients with cancer and incidental PE, the prognostic effect of concomitant incidental DVT is unknown. In this retrospective study, we examined the effect of incidental DVT on all-cause mortality in such patients. Adjusted Cox multivariate regression analysis was used for relevant covariates. From January 2010 to March 2018, we included 200 patients (mean age, 65.3 ± 12.4 years) who were followed up for 12.5 months (interquartile range 7.4-19.4 months). Of these patients, 62% had metastases, 31% had concomitant incidental DVT, and 40.1% (n = 81) died during follow-up. All-cause mortality did not increase in patients with DVT (hazard ratio [HR] 1.01, 95% confidence interval [CI] 0.43-2.75, p = 0.855). On multivariate analysis, weight (adjusted HR 0.96, 95% CI 0.92-0.99, p = 0.032), and metastasis (adjusted HR 10.26, 95% CI 2.35-44.9, p = 0.002) were predictors of all-cause mortality. In conclusion, low weight and presence of metastases were associated with all-cause mortality, while presence of concomitant DVT was unrelated to poorer survival.

Comparison of 4 Acute Pulmonary Embolism Mortality Risk Scores in Patients Evaluated by Pulmonary Embolism Response Teams

IMPORTANCE

The risk of death from acute pulmonary embolism can range as high as 15%, depending on patient factors at initial presentation. Acute treatment decisions are largely based on an estimate of this mortality risk.

OBJECTIVE

To assess the performance of risk assessment scores in a modern, US cohort of patients with acute pulmonary embolism.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cohort study was conducted between October 2016 and October 2017 at 8 hospitals participating in the Pulmonary Embolism Response Team (PERT) Consortium registry. Included patients were adults who presented with acute pulmonary embolism and had sufficient information in the medical record to calculate risk scores. Data analysis was performed from March to May 2020.

MAIN OUTCOMES AND MEASURES

All-cause mortality (7- and 30-day) and associated discrimination were assessed by the area under the receiver operator curve (AUC).

RESULTS

Among 416 patients with acute pulmonary embolism (mean [SD] age, 61.3 [17.6] years; 207 men [49.8%]), 7-day mortality in the low-risk groups ranged from 1.3% (1 patient) to 3.1% (4 patients), whereas 30-day mortality ranged from 2.6% (1 patient) to 10.2% (13 patients). Among patients in the highest-risk groups, the 7-day mortality ranged from 7.0% (18 patients) to 16.3% (7 patients), whereas 30-day mortality ranged from 14.4% (37 patients) to 26.3% (26 patients). Each of the risk stratification tools had modest discrimination for 7-day mortality (AUC range, 0.616-0.666) with slightly lower discrimination for 30-day mortality (AUC range, 0.550-0.694).

CONCLUSIONS AND RELEVANCE

These findings suggest that commonly used risk tools for acute pulmonary embolism have modest estimating ability. Future studies to develop and validate better risk assessment tools are needed.

Pulmonary vasodilation in acute pulmonary embolism - a systematic review

Acute pulmonary embolism is the third most common cause of cardiovascular death. Pulmonary embolism increases right ventricular afterload, which causes right ventricular failure, circulatory collapse and death. Most treatments focus on removal of the mechanical obstruction caused by the embolism, but pulmonary vasoconstriction is a significant contributor to the increased right ventricular afterload and is often left untreated. Pulmonary thromboembolism causes mechanical obstruction of the pulmonary vasculature coupled with a complex interaction between humoral factors from the activated platelets, endothelial effects, reflexes and hypoxia to cause pulmonary vasoconstriction that worsens right ventricular afterload. Vasoconstrictors include serotonin, thromboxane, prostaglandins and endothelins, counterbalanced by vasodilators such as nitric oxide and prostacyclins. Exogenous administration of pulmonary vasodilators in acute pulmonary embolism seems attractive but all come with a risk of systemic vasodilation or worsening of pulmonary ventilation-perfusion mismatch. In animal models of acute pulmonary embolism, modulators of the nitric oxide-cyclic guanosine monophosphate-protein kinase G pathway, endothelin pathway and prostaglandin pathway have been investigated. But only a small number of clinical case reports and prospective clinical trials exist. The aim of this review is to give an overview of the causes of pulmonary embolism-induced pulmonary vasoconstriction and of experimental and human investigations of pulmonary vasodilation in acute pulmonary embolism.

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.

Reducing the hospital burden associated with the treatment of pulmonary embolism

Pulmonary embolism (PE) is the most feared clinical presentation of venous thromboembolism (VTE). Patients with PE have traditionally been treated in hospital; however, many are at low risk of adverse outcomes and current guidelines suggest outpatient treatment as an option. Outpatient treatment of PE offers several advantages, including reduced risk of hospital-acquired conditions and potential cost savings. Despite this, patients with low-risk PE are still frequently hospitalized for treatment. This narrative review summarizes current guideline recommendations for the identification of patients with low-risk PE who are potentially suitable for outpatient treatment, using prognostic assessment tools (e.g. the Pulmonary Embolism Severity Index [PESI] and simplified PESI) and clinical exclusion criteria (e.g. Hestia criteria) alone or in combination with additional cardiac assessments. Treatment options are discussed along with recommendations for the follow-up of patients managed in the non-hospital environment. The available data on outpatient treatment of PE are summarized, including details on patient selection, anticoagulant choice, and short-term outcomes in each study. Accumulating evidence suggests that outcomes in patients with low-risk PE treated as outpatients are at least as good as, if not better than, those of patients treated in the hospital. With mounting pressures on health care systems worldwide, increasing the proportion of patients with PE treated as outpatients has the potential to reduce health care burdens associated with VTE.

A retrospective analysis of outcomes in low- and intermediate-high-risk pulmonary embolism patients managed on an ambulatory medical unit in the UK

Pulmonary embolism (PE) is common and guidelines recommend outpatient care only for PE patients with low predicted mortality. Outcomes for patients with intermediate-to-high predicted mortality managed as outpatients are unknown. Electronic records were analysed for adults with PE managed on our ambulatory care unit over 2 years. Patients were stratified into low or intermediate-to-high mortality risk groups using the Pulmonary Embolism Severity Index (PESI). Primary outcomes were the proportion of patients ambulated, 30-day all-cause mortality, 30-day PE-specific mortality and 30-day re-admission rate. Of 199 PE patients, 74% were ambulated and at 30 days, all-cause mortality was 2% (four out of 199) and PE-specific mortality was 1% (two out of 199). Ambulated patients had lower PESI scores, better vital signs and lower troponin levels (morning attendance favoured ambulation). Over a third of ambulated patients had an intermediate-to-high risk PESI score but their all-cause mortality rate was low at 1.9% (one out of 52). In patients with intermediate-to-high risk, oxygen saturation was higher and pulse rate lower in those who were ambulated. Re-admission rate did not differ between ambulated and admitted patients. Two-thirds of patients with intermediate-to-high risk PE were ambulated and their mortality rate remained low. It is possible for selected patients with intermediate-to-high risk PESI scores to be safely ambulated.

Changes in treatment and outcomes after creation of a pulmonary embolism response team (PERT), a 10-year analysis

Multidisciplinary pulmonary embolism response teams (PERTs) are being implemented to improve care of patients with life-threatening PE. We sought to determine how the creation of PERT affects treatment and outcomes of patients with serious PE. A pre- and post-intervention study was performed using an interrupted time series design, to compare patients with PE before (2006-2012) and after (2012-2016) implementation of PERT at a university hospital. T-tests, Chi square tests and logistic regression were used to compare outcomes, and multivariable regression were used to adjust for differences in PE severity. Two-sided p-value < 0.05 was considered significant. For the interrupted time-series analysis, data was divided into mutually exclusive 6-month time periods (11 pre- and 7 post-PERT). To examine changes in treatment and outcomes associated with PERT, slopes and change points were compared pre- and post-PERT. Two-hundred and twelve pre-PERT and 228 post-PERT patients were analyzed. Patient demographics were generally similar, though pre-PERT, PE were more likely to be low-risk (37% vs. 19%) while post-PERT, PE were more likely to be submassive (32% vs. 49%). More patients underwent catheter directed therapy (1% vs. 14%, p = < 0.0001) or any advanced therapy (19 [9%] vs. 44 [19%], p = 0.002) post PERT. Interrupted time series analysis demonstrated that this increase was sudden and coincident with implementation of PERT, and most noticeable among patients with submassive PE. There were no differences in major bleeding or mortality pre- and post-PERT. While the use of advanced therapies, particularly catheter-directed therapies, increased after creation of PERT, especially among patients with submassive PE, there was no apparent increase in bleeding.

Impact of chronic right ventricular pressure overload in short-term outcomes of acute pulmonary embolism: A retrospective analysis

PURPOSE

Evaluate the association between chronic right ventricle (RV) dysfunction by transthoracic echocardiogram (TTE) and outcomes in patients with acute pulmonary embolism (PE).

METHODS

This was a retrospective analysis of TTE findings in acute PEs. TTEs were used to classify the presence of chronic right ventricular pressure overload (RPVO), defined as RV hypertrophy or RV systolic pressure (RVSP) >50 mmHg, acute RVPO, defined as RV dysfunction not meeting the chronic RVPO definition, or no RV dysfunction. The primary outcome was a composite of death or need for advanced PE therapies at 7 days.

RESULTS

Of 466 patients, 288 had evidence of RV dysfunction. Thirty percent (140) had evidence of chronic RVPO and 148 patients had evidence of acute RVPO. Chronic RVPO patients were older (P = .004), more likely to have COPD, and had lower heart rates and troponin-t values. The acute RVPO patients included more women and were less likely to have a prior PE. There was no difference in outcomes between the acute and chronic RVPO cohorts.

CONCLUSIONS

Chronic RVPO patients had lower heart rates and troponin-t values. Despite these differences there were no differences in need for advanced therapeutic interventions or 7 day mortality.

Impact of symptomatic atherosclerosis in patients with pulmonary embolism

BACKGROUND

Atherosclerosis is associated with increased cardiovascular mortality. Associations between venous thromboembolism and atherosclerosis were recently reported. We aimed to investigate the impact of symptomatic atherosclerosis on adverse outcomes in patients with pulmonary embolism (PE) and to identify significant differences among patients with PE stratified by symptomatic atherosclerosis.

METHODS

Patients were selected by screening the nationwide inpatients sample for PE (ICD-code I26) stratified by symptomatic atherosclerosis (composite of coronary artery disease [ICD-code I25], myocardial infarction [ICD-code I21], ischemic stroke [ICD-code I63], and/or atherosclerotic arterial diseases [ICD-code I70]). We compared PE patients with (PE + Athero) and without (PE - Athero) symptomatic atherosclerosis and analysed the impact of symptomatic atherosclerosis on adverse outcomes.

RESULTS

Overall, 213,995 patients with PE (54.2% females) were included in this analysis. Of these, 30,157 (14.1%) had symptomatic atherosclerosis with age-dependent incline. Deep vein thrombosis or thrombophlebitis (45.1% vs. 36.9%, P < 0.001) was more commonly observed in the PE - Athero group (Odds Ratio (OR) 0.713 [95% CI 0.695-0.731], P < 0.001). In-hospital mortality (12.1% vs. 9.6%, P < 0.001) and adverse in-hospital events (16.8% vs. 12.6%, P < 0.001) were affected by symptomatic atherosclerosis; both in-hospital mortality (OR 1.107 [95% CI 1.061-1.155], P < 0.001) and adverse in-hospital outcomes (OR 1.143 [95%CI 1.102-1.186], P < 0.001) were affected independently of age, gender, comorbidities, and reperfusion treatments.

CONCLUSIONS

Symptomatic atherosclerosis in patients with PE increased with age and was associated with a poorer outcome. Cardiovascular-atherosclerotic diseases might play a major role in thrombus formation in isolated PE.

The Prevalence of Concomitant Deep Vein Thrombosis, Symptomatic or Asymptomatic, Proximal or Distal, in Patients With Symptomatic Pulmonary Embolism

Patients with pulmonary embolism (PE) may have symptomatic or asymptomatic concomitant deep vein thrombosis (DVT). The reported prevalence of PE-associated DVT is variable, and thus, the utility of routine testing is controversial. The aim of our study was to analyze the prevalence of DVT and the factors associated with proximal DVT/whole-leg DVT in patients with symptomatic PE. In 428 consecutive patients (mean age: 59 ± 16.4 years; 52.3% men), we performed clinical examination and complete bilateral compression ultrasound and ascertained medical history and risk factors for DVT/PE. χ² and t tests were used. Deep vein thrombosis was found in 70.6%; proximal DVT in 49.5%. Sensitivity/specificity of DVT symptoms was 42.7%/93.7% for whole-leg DVT and 47.6%/83.3% for proximal DVT. Male gender significantly prevailed among those with whole-leg DVT and with proximal DVT (58.9% and 61.8%). Active malignancy was significantly more frequent in the patients with proximal DVT than without proximal DVT (10.4% vs 3.7%). In conclusion, the prevalence of PE-associated DVT is quite high but clinical diagnosis is unreliable. In our group, male gender and active malignancy were significantly associated with the presence of concomitant proximal DVT.

Non-vitamin K antagonist oral anticoagulants for pulmonary embolism: who, where and for how long?

INTRODUCTION

Acute pulmonary embolism (PE) is a relatively common cardiopulmonary emergency that is a major cause of hospitalization and morbidity and is the primary cause of mortality associated with venous thromboembolism (VTE). During the last decade, one of the biggest changes in the management of PE has been the approval of four non-vitamin K antagonist oral anticoagulants (NOACs; apixaban, dabigatran, edoxaban and rivaroxaban) for the treatment of PE and deep vein thrombosis and secondary prevention of VTE. Areas covered: This article reviews the evolving management of PE in the NOAC era and addresses three fundamental questions: who should receive NOACs over conventional heparin/vitamin K antagonist regimens for the treatment of acute PE; should patients be treated as inpatients or outpatients; and how long should patients be treated to reduce the risk of recurrence? Expert commentary: The management of PE is changing. NOACs provide new anticoagulant treatment options for patients with PE, based on Phase III clinical study results. The consistent efficacy and safety profile of NOACs across many PE patient subgroups, including the elderly, fragile patients, those with active cancer and high-risk (right ventricular dysfunction) patients, suggests NOAC use will increase among these patients.

Short- and long-term mortality after pulmonary embolism in patients with and without cancer

Pulmonary embolism (PE) is a major cause of mortality and morbidity. It is known that the risk of death varies by provoking factors; however, it is unknown if the risk of death persists beyond the initial diagnosis among patients with cancer-associated and non-cancer provoked patients. In this study, we aimed to investigate the effect of cancer on overall, short- and long-term mortality in a cohort of consecutive incident PE patients. Using administrative databases, we identified all incident cases of PE between 2004 and 2012 in Alberta, Canada. Cases were stratified by provoking factors (i.e. unprovoked, provoked, and cancer-associated). A multivariate Cox survival model was used to estimate the hazard ratios of short- and long-term death. We identified 8641 patients with PE, among which 42.2% were unprovoked, 37.9% were provoked and 19.9% were cancer-associated. The 1-year and 5-year survival probabilities were 60% (95% CI: 57-64%) and 39% (95% CI: 36-43%) in patients with cancer-associated PE, 93% (95% CI: 92-94%) and 80% (95% CI: 78-81%) in provoked PE, and 94% (95% CI: 93-95%) and 85% (95% CI: 83-87%) in unprovoked PE, respectively. Compared to patients with unprovoked events, both short-term and long-term survival in patients with cancer-associated PE have a higher observed risk of all-cause mortality in all age groups ( p<0.001). In contrast, patients with provoked events had a similar short- and long-term all-cause mortality. While PE has a significant mortality in all risk groups, patients with cancer have a higher risk of short-term mortality compared to patients with unprovoked PE.

Metabolomic analysis of 92 pulmonary embolism patients from a nested case-control study identifies metabolites associated with adverse clinical outcomes

Essentials Risk-stratification often fails to predict clinical deterioration in pulmonary embolism (PE). First-ever high-throughput metabolomics analysis of risk-stratified PE patients. Changes in circulating metabolites reflect a compromised energy metabolism in PE. Metabolites play a key role in the pathophysiology and risk stratification of PE.

SUMMARY

Background Patients with acute pulmonary embolism (PE) exhibit wide variation in clinical presentation and outcomes. Our understanding of the pathophysiologic mechanisms differentiating low-risk and high-risk PE is limited, so current risk-stratification efforts often fail to predict clinical deterioration and are insufficient to guide management. Objectives To improve our understanding of the physiology differentiating low-risk from high-risk PE, we conducted the first-ever high-throughput metabolomics analysis (843 named metabolites) comparing PE patients across risk strata within a nested case-control study. Patients/methods We enrolled 92 patients diagnosed with acute PE and collected plasma within 24 h of PE diagnosis. We used linear regression and pathway analysis to identify metabolites and pathways associated with PE risk-strata. Results When we compared 46 low-risk with 46 intermediate/high-risk PEs, 50 metabolites were significantly different after multiple testing correction. These metabolites were enriched in the following pathways: tricarboxylic acid (TCA) cycle, fatty acid metabolism (acyl carnitine) and purine metabolism, (hypo)xanthine/inosine containing. Additionally, energy, nucleotide and amino acid pathways were downregulated in intermediate/high-risk PE patients. When we compared 28 intermediate-risk with 18 high-risk PE patients, 41 metabolites differed at a nominal P-value level. These metabolites were enriched in fatty acid metabolism (acyl cholines), and hemoglobin and porphyrin metabolism. Conclusion Our results suggest that high-throughput metabolomics can provide insight into the pathophysiology of PE. Specifically, changes in circulating metabolites reflect compromised energy metabolism in intermediate/high-risk PE patients. These findings demonstrate the important role metabolites play in the pathophysiology of PE and highlight metabolomics as a potential tool for risk stratification of PE.

Ultrasound Assisted Catheter-Directed Thrombolysis of Acute Pulmonary Embolism: A Review of Current Literature

Pulmonary embolism continues as a very common and also presumably life-threatening disorder. For affected individuals with intermediate- as well as high-risk pulmonary embolism, catheter-based revascularization procedures have developed a possible substitute for systemic thrombolysis or for surgical embolectomy. Ultrasound-assisted catheter-directed thrombolysis is an innovative catheter-based approach; which is the main purpose of the present review article. Ultrasound-assisted catheter-directed thrombolysis is much more efficacious in reversing right ventricular dysfunction as well as dilatation in comparison to anticoagulation alone in individuals at intermediate risk. However, a direct comparison of ultrasound-assisted thrombolysis with systemic thrombolysis or surgical thrombectomy is not available. Ultrasound-assisted thrombolysis with early intrapulmonary thrombolytic bolus could also be successful in high-risk patients, but unfortunately, data from randomized trials is limited. This review article recapitulates existing information on ultrasound-assisted thrombolysis for acute pulmonary embolism.

Epidemiology, Pathophysiology, Stratification, and Natural History of Pulmonary Embolism

Pulmonary embolism (PE) is a common and potentially fatal form of venous thromboembolism that can be challenging to diagnose and manage. PE occurs when there is obstruction of the pulmonary vasculature and is a common cause of morbidity and mortality in the United States. A combination of acquired and inherited factors may contribute to the development of this disease and should be considered, since they have implications for both susceptibility to PE and treatment. Patients with suspected PE should be evaluated efficiently to diagnose and administer therapy as soon as possible, but the presentation of PE is variable and nonspecific so diagnosis is challenging. PE can range from small, asymptomatic blood clots to large emboli that can occlude the pulmonary arteries causing sudden cardiovascular collapse and death. Thus, risk stratification is critical to both the prognosis and management of acute PE. In this review, we discuss the epidemiology, risk factors, pathophysiology, and natural history of PE and deep vein thrombosis.

Comparison of Emergency Department Patients to Inpatients Receiving a Pulmonary Embolism Response Team (PERT) Activation

OBJECTIVES

The development of pulmonary embolism response teams (PERTs) has been widely adopted nationally with the goal of providing multidisciplinary care to patients with high-risk PE. Most PERT activations originate from the emergency department (ED), while others are from the intensive care unit (ICU) or inpatient floors. It is unclear if ED PERT activations differ from non-ED PERT activation in terms of presentation, management, and outcome.

METHODS

We enrolled a consecutive cohort of patients for whom PERT was activated at an urban academic medical center. We compared three groups of PERT activations based on whether the activation originated from the ED, ICU, or a non-ICU inpatient floor. We compared these groups in terms of the proportion of PERT activations that occurred during day, evening, or weekend hours and the proportion of confirmed PE. We also compared PE severity, treatment, and outcomes across locations. We tested differences using chi-square tests, with a two-tailed p-value of <0.05 considered statistically significant.

RESULTS

We enrolled 561 patients, of whom 449 (79.5%) had confirmed PE. The mean ± SD age of patients with confirmed PE was 61 ± 17 years, and 300 (53.5%) were male. Activations from the ED (n = 283, 88.4%) or floor (n = 100, 74.6%) were more likely to be for confirmed PE than activations from the ICU (n = 63, 58.9%; p < 0.0001). There was a statistical difference in the time of day of PERT activation with the ED having more activations during night hours than the ICU or floors (p = 0.004). Most activations for confirmed, massive PE originated from the ICU (n = 41, 65.1%), followed by the ED (n = 82, 29%) and inpatient floors (n = 22, 22%; p < 0.0001). Most activations from the ED (n = 155, 54.8%) and floors (n = 55, 55%) were for submassive PE. The use of thrombolysis or thrombectomy was more common among ICU patients (n = 18, 33.3%), followed by ED patients (n = 53, 19.6%) and then floor patients (n = 8, 8.2%). Mortality and major bleeding events were most common among ICU patients and similar among ED and floor patients.

CONCLUSIONS

Pulmonary embolism response team activations from different clinical locations differ in terms of patient presentation, PE confirmation, treatments, and outcomes. PERTs should be customized to support the different needs of each clinical area.

The creation and implementation of an outpatient pulmonary embolism treatment protocol

The ability to rapidly and accurately risk-stratify patients with venous thromboembolism (VTE), and the availability of direct acting oral anticoagulants have reduced the need for intravenous anticoagulation for patients with deep vein thrombosis (DVT) and pulmonary embolism (PE). Emergency physicians are generally reluctant to discharge patients with VTE without defined and reliable follow up in place, and VTE patients treated with anticoagulants can be at risk for complications related to recurrent VTE and bleeding. In addition, screening for associated diseases (e.g. cancer, hypercoagulable states) may be indicated. Therefore, the outpatient treatment of low risk VTE requires coordinated effort and reliable follow up. By leveraging detailed outcome data and collaborative relationships, we have created a protocol for the safe outpatient treatment of patients with low risk DVT and PE. Our protocol is data driven and designed to address barriers to outpatient VTE management. We expect our protocol to result in improved patient satisfaction, more efficient emergency department (ED) throughput, and decreased cost. Applied nationally, the outpatient treatment of select patients with DVT and PE could have major public health and economic impact.

Assessment of Right Ventricular Strain by Computed Tomography Versus Echocardiography in Acute Pulmonary Embolism

BACKGROUND

Right ventricular strain (RVS) identifies patients at risk of hemodynamic deterioration from pulmonary embolism (PE). Our hypothesis was that chest computed tomography (CT) can provide information about RVS analogous to transthoracic echocardiography (TTE) and that RVS on CT is associated with adverse outcomes after PE.

METHODS

Consecutive emergency department patients with acute PE were prospectively enrolled and clinical, biomarker, and imaging data were recorded. CTs were overread by two radiologists. We compared diagnoses of RVS on CT (defined as right ventricle:left ventricle ratio ≥ 0.9 or interventricular septal bowing) to echocardiography (defined as right ventricular hypokinesis, right ventricular dilatation, or interventricular septal bowing). We calculated the test characteristics (with 95% confidence interval) of CT and TTE for a composite outcome of severe clinical deterioration, thrombolysis/thrombectomy, or death within 5 days.

RESULTS

A total of 298 patients were enrolled; 274 had CT and 118 had formal TTE. Of the 104 patients who had both CT and TTE, the mean (±SD) age was 58 (±17) years; 50 (48%) were female and 88 (85%) were Caucasian. Forty-two (40%) had RVS by TTE and 75 (72%) had RVS by CT. CT and TTE agreed on the presence or absence of RVS in 61 (59%) cases (κ = 0.24). Using TTE as criterion standard, the test characteristics of CT for RVS were as follows: sensitivity = 88%, specificity = 39%, positive predictive value = 49%, and negative predictive value = 83%. Fourteen (13%) patients experienced severe clinical deterioration or required hospital-based intervention within 5 days. This occurred in 30% of patients with RVS on both TTE and CT, 20% of patients with RVS on TTE alone, 3% of patients with RVS on CT alone, and 4% of patients without RVS on either modality.

CONCLUSIONS

In acute PE, CT is highly sensitive but only moderately specific for RVS compared to TTE. RVS on both CT and TTE predicts more events than either modality alone. TTE confers additional positive prognostic value compared to CT in predicting post-PE clinical deterioration.

Relation Among Clot Burden, Right-Sided Heart Strain, and Adverse Events After Acute Pulmonary Embolism

Computed tomography pulmonary angiogram (CTPA) provides a volumetric assessment of clot burden in acute pulmonary embolism (PE). However, it is unclear if clot burden is associated with right-sided heart strain (RHS) or adverse clinical events (ACE). We prospectively enrolled Emergency Department patients with PE (in CTPA) from 2008 to 2011. We assigned 1 to 9 points as clot burden score, based on whether emboli were saddle, central, lobar, segmental, and subsegmental. We evaluated a novel score (the "CT-PASS") based on the sum (in millimeters) of the largest filling defects in the right and left pulmonary vasculature. Our primary outcome was RHS, defined by imaging (echocardiography or CTPA) or cardiac biomarkers. Our secondary outcomes included 5-day ACE. We included 271 patients (50% women), with a mean age of 59 ± 17 years. Based on CTPA, 131 patients (48%) had central PE (clot burden score ≥5 points). The median CT-PASS was 9.1 mm (interquartile range 4.9 to 16.4). In univariate analysis, higher clot burden (highest quartile CT-PASS) was associated with RHS (p = 0.003). In multivariate analysis, after adjusting for RHS, age, and gender, central PE (odds ratio [OR] 2.92, 95% confidence interval [CI] 1.10 to 7.81) and CT-PASS >20 mm (OR 3.54, 95% CI 1.39 to 8.97) were significantly associated with ACE. However, this association of central PE with ACE was not statistically significant after excluding patients with shock index >1 (OR 2.56, 95% CI 0.62 to 10.64). In conclusion, highest quartile CT-PASS was associated with RHS and central PE and ACE, but this association was not statistically significant in hemodynamically stable PE [corrected].

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.

Prognostic Value of Right Ventricular Dysfunction Markers for Serious Adverse Events in Acute Normotensive Pulmonary Embolism

BACKGROUND

Right ventricular dysfunction (RVD) in pulmonary embolism (PE) has been associated with increased morbidity. Tools for RVD identification are not well defined. The prognostic value of RVD markers to predict serious adverse events (SAE) during hospitalization is unclear.

OBJECTIVE

Prospectively compare the incidence of SAE in normotensive emergency department patients with PE based upon RVD by goal-directed echocardiography (GDE), cardiac biomarkers, and right-to-left ventricle ratio by computed tomography (CT). Simplified Pulmonary Embolism Severity Index (sPESI) was calculated. Deaths and readmissions within 30 days were recorded.

METHODS

Consecutive normotensive PE patients underwent GDE focused on RVD (RV enlargement, hypokinesis, or septal bowing), serum troponin, and brain natriuretic peptide (BNP), and evaluation of the CT ventricle ratio. In-hospital SAE and complications within 30 days were recorded.

RESULTS

We enrolled 123 normotensive PE patients (median age 59 years, 49% female). Twenty-six of 123 (26%) patients had one or more SAE. RVD was detected in 26% by GDE, in 39% by biomarkers, and in 38% with CT. In-hospital SAE included one death, six respiratory interventions, six dysrhythmias, three major bleeding episodes, and 21 hypotension episodes. Forty-one percent of patients RVD positive by GDE had SAE, compared to the 18% RVD negative by GDE. Odds ratios for GDE, CT, BNP, troponin, and sPESI for SAE were 3.2 (95% confidence interval [CI] 1.2-8.5), 2.0 (95% CI 0.8-5.1), 3.3 (95% CI 1.3-8.6), 4.2 (95% CI 1.4-13.5), and 2.9 (95% CI 1.1-8.3), respectively. Five patients had non-PE-related deaths within 30 days.

CONCLUSION

The incidence of SAE within days of PE was significant in our cohort. Those with RVD had an increased risk of nonmortality SAE.

Pulmonary embolism: the diagnosis, risk-stratification, treatment and disposition of emergency department patients

The diagnosis or exclusion of pulmonary embolism (PE) remains challenging for emergency physicians. Symptoms can be vague or non-existent, and the clinical presentation shares features with many other common diagnoses. Diagnostic testing is complicated, as biomarkers, like the D-dimer, are frequently false positive, and imaging, like computed tomography pulmonary angiography, carries risks of radiation and contrast dye exposure. It is therefore incumbent on emergency physicians to be both vigilant and thoughtful about this diagnosis. In recent years, several advances in treatment have also emerged. Novel, direct-acting oral anticoagulants make the outpatient treatment of low risk PE easier than before. However, the spectrum of PE severity varies widely, so emergency physicians must be able to risk-stratify patients to ensure the appropriate disposition. Finally, PE response teams have been developed to facilitate rapid access to advanced therapies (e.g., catheter directed thrombolysis) for patients with high-risk PE. This review will discuss the clinical challenges of PE diagnosis, risk stratification and treatment that emergency physicians face every day.

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.

Comparison of Four Bleeding Risk Scores to Identify Rivaroxaban-treated Patients With Venous Thromboembolism at Low Risk for Major Bleeding

OBJECTIVES

Outpatient treatment of acute venous thromboembolism (VTE) requires the selection of patients with a low risk of bleeding during the first few weeks of anticoagulation. The accuracy of four systems, originally derived for predicting bleeding in VTE treated with vitamin K antagonists (VKAs), was assessed in VTE patients treated with rivaroxaban.

METHODS

All patients treated with rivaroxaban in the multinational EINSTEIN deep vein thrombosis (DVT) and pulmonary embolism (PE) trials were included. Major bleeding was defined as ≥2 g/dL drop in hemoglobin or ≥2-unit blood transfusion, bleeding in critical area, or bleeding contributing to death. The authors examined the incidence of major bleeding in patients with low-risk assignment by the systems of Ruiz-Gimenez et al. (score = 0 to 1), Beyth et al. (score = 0), Kuijer et al. (score = 0), and Landefeld and Goldman. (score = 0). For clinical relevance, the definition of low risk for all scores except Kuijer includes all patients < 65 years with no prior bleeding history and no comorbid conditions (current cancer, renal insufficiency, diabetes mellitus, anemia, prior stroke, or myocardial infarction).

RESULTS

A total of 4,130 patients (1,731 with DVT only, 2,399 with PE with or without DVT) were treated with rivaroxaban for a mean (±SD) duration of 207.6 (±95.9) days. Major bleeding occurred in 1.0% (40 of 4,130; 95% confidence interval [CI] = 0.7% to 1.3%) overall. Rates of major bleeding for low-risk patients during the entire treatment period were similar: Ruiz-Gimenez et al., 12 of 2,622 (0.5%; 95% CI = 0.2% to 0.8%); Beyth et al., nine of 2,249 (0.4%; 95% CI = 0.2% to 0.8%); Kuijer et al., four of 1,186 (0.3%; 95% CI = 0.1% to 0.9%); and Landefeld and Goldman, 11 of 2,407 (0.5%; 95% CI = 0.2% to 0.8%). At 30 days, major bleed rates for low-risk patients were as follows: Ruiz-Gimenez et al., five of 2,622 (0.2%; 95% CI = 0.1% to 0.4%); Beyth et al., five of 2,249 (0.2%; 95% CI = 0.1% to 0.5%); Kuijer et al., three of 1,186 (0.3%; 95% CI = 0.1% to 0.7%); and Landefeld and Goldman, seven of 2,407 (0.3%; 95% CI = 0.1% to 0.6%). No low-risk patient had a fatal bleed.

CONCLUSIONS

Four scoring systems that use criteria obtained in routine clinical practice, derived to predict low bleeding risk with VKA treatment for VTE, identified patients with less than a 1% risk of major bleeding during full-course treatment with rivaroxaban.