The effects of cause of death classification on prognostic assessment of patients with pulmonary embolism

Integration of Extracorporeal Membrane Oxygenation into the Management of High-Risk Pulmonary Embolism: An Overview of Current Evidence

High-risk pulmonary embolism (PE) refers to a large embolic burden causing right ventricular failure and hemodynamic instability. It accounts for approximately 5% of all cases of PE but contributes significantly to overall PE mortality. Systemic thrombolysis is the first-line revascularization therapy in high-risk PE. Surgical embolectomy or catheter-directed therapy is recommended in patients with an absolute contraindication to systemic thrombolysis. Extracorporeal membrane oxygenation (ECMO) provides respiratory and hemodynamic support for the most critically ill PE patients with refractory cardiogenic shock or cardiac arrest. The complex management of these individuals requires urgent yet coordinated multidisciplinary care. In light of existing evidence regarding the utility of ECMO in the management of high-risk PE patients, a number of possible indications for ECMO utilization have been suggested in the literature. Specifically, in patients with refractory cardiac arrest, resuscitated cardiac arrest, or refractory shock, including in cases of failed thrombolysis, venoarterial ECMO (VA-ECMO) should be considered, either as a bridge to percutaneous or surgical embolectomy or as a bridge to recovery after surgical embolectomy. We review here the current evidence on the use of ECMO as part of the management strategy for the highest-risk presentations of PE and summarize the latest data in this indication.

Risk stratification of acute pulmonary embolism

Approximately 5% of pulmonary embolism (PE) cases present with persistent hypotension, obstructive shock, or cardiac arrest. Given the high short-term mortality, management of high-risk PE cases focuses on immediate reperfusion therapies. Risk stratification of normotensive PE is important to identify patients with an elevated risk of hemodynamic collapse or an elevated risk of major bleeding. Risk stratification for short-term hemodynamic collapse includes assessment of physiological parameters, right heart dysfunction, and identification of comorbidities. Validated tools such as European Society of Cardiology guidelines and Bova score can identify normotensive patients with PE and an elevated risk of subsequent hemodynamic collapse. At present, we lack high-quality evidence to recommend one treatment over another (systemic thrombolysis, catheter-directed therapy, or anticoagulation with close monitoring) for patients at elevated risk of hemodynamic collapse. Newer, less well-validated scores such as BACS and PE-CH may help identify patients at a high risk of major bleeding following systemic thrombolysis. The PE-SARD score may identify those at risk of major anticoagulant-associated bleeding. Patients at low risk of short-term adverse outcomes can be considered for outpatient management. The simplified Pulmonary Embolism Severity Index score or Hestia criteria are safe decision aids when combined with physician global assessment of the need for hospitalization following the diagnosis of PE.

Risk Stratification in Patients with Acute Pulmonary Embolism: Current Evidence and Perspectives

Risk stratification is one of the cornerstones of the management of acute pulmonary embolism (PE) and determines the choice of both diagnostic and therapeutic strategies. The first step is the identification of patent circulatory failure, as it is associated with a high risk of immediate mortality and requires a rapid diagnosis and prompt reperfusion. The second step is the estimation of 30-day mortality based on clinical parameters (e.g., original and simplified version of the pulmonary embolism severity index): low-risk patients without right ventricular dysfunction are safely managed with ambulatory anticoagulation. The remaining group of hemodynamically stable patients, labeled intermediate-risk PE, requires hospital admission, even if most of them will heal without complications. In recent decades, efforts have been made to identify a subgroup of patients at an increased risk of adverse outcomes (intermediate-high-risk PE), who might benefit from a more aggressive approach, including reperfusion therapies and admission to a monitored unit. The cur-rent approach, combining markers of right ventricular dysfunction and myocardial injury, has an insufficient positive predictive value to guide primary thrombolysis. Sensitive markers of circulatory failure, such as plasma lactate, have shown interesting prognostic accuracy and may play a central role in the future. Furthermore, the improved security of reduced-dose thrombolysis may enlarge the indication of this treatment to selected intermediate–high-risk PE.

Predictive value of heart failure with reduced versus preserved ejection fraction for outcome in pulmonary embolism

AIMS

This study aimed to investigate whether the risk of short-term mortality is different in pulmonary embolism (PE) patients who have heart failure with reduced ejection fraction (HFrEF) as compared with those with heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Predictive value of HFrEF or HFpEF for 7-day (intrahospital) and 30-day all-cause mortality was determined in the cohort of 1055 out of 1201 consecutive acute PE patients from the Serbian multicentre PE registry. Patients were classified into either HFrEF or HFpEF group, according to guideline-proposed criteria. A 7-day (intrahospital) and 30-day all-cause mortality was 18.5% vs. 7.3% vs. 4.5% (P < 0.001) and 22.2% vs. 16.3% vs. 7.9% (P < 0.001) for patients with the history of HFrEF, HFpEF, and without HF, respectively. Multivariable analysis adjusted to age, gender, history of chronic obstructive pulmonary disease, diabetes mellitus, arterial hypertension, presence of atrial fibrillation, and mortality risk assessment at admission has shown that only HFrEF, but not HFpEF, was an independent predictor for 7-day mortality (hazard ratio 2.22, 95% confidence interval 1.25-4,38.41, P = 0.021) and neither HFrEF or HFpEF was an independent predictor for 30-day mortality. Among various admission parameters associated to PE outcome, only systolic pressure in HFrEF patients (P < 0.001), heart rate (P = 0.01), and right ventricle systolic pressure (P = 0.039) in HFpEF patients were significantly different in patients who died compared with those who survived at 7 days.

CONCLUSIONS

Our study has shown that the presence of previous history of HFrEF, but not HFpEF, in acute PE is an independent risk factor for mortality at 7 days.

Cardiac Troponins in Low-Risk Pulmonary Embolism Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with low-risk pulmonary embolism (PE) should be considered as per current scoring systems for ambulatory treatment. However, there is uncertainty whether patients with low scores and positive troponins should require hospitalization.

METHODS

We searched MEDLINE, SCOPUS, and Cochrane Library databases from inception to December 2016 and collected longitudinal studies that evaluated the prognostic value of troponins in patients with low-risk PE. The primary outcome measure was 30-day all-cause mortality. We calculated odds ratio (OR), likelihood ratios (LRs), and 95% confidence intervals (CI) by using randomeffects models.

RESULTS

The literature search identified 117 candidate articles, of which 16 met the criteria for review. Based on pulmonary embolism severity index (PESI) or simplified PESI score, 1.2% was the all-cause mortality rate across 2,662 participants identified as low-risk. A positive troponin status in patients with low-risk PE was associated with an increased risk of 30-day all-cause mortality (odds ratio [OR]: 4.79; 95% confidence interval [CI]: 1.11 to 20.68). The pooled likelihood ratios (LRs) for all-cause mortality were positive LR 2.04 (95% CI, 1.53 to 2.72) and negative LR 0.072 (95% CI, 0.37 to 1.40).

CONCLUSIONS

The use of positive troponin status as a predictor of increased mortality in low-risk PE patients exhibited relatively poor performance given the crossed negative LR CI (1.0) and modest positive LR. Larger prospective trials must be conducted to elucidate if patients with low-risk PE and positive troponin status can avoid hospitalization.

Sex differences in the characteristics and short-term prognosis of patients presenting with acute symptomatic pulmonary embolism

Background

We sought to examine sex-related differences in the characteristics and outcome in patients presenting with acute symptomatic pulmonary embolism (PE).

Methods

We conducted a retrospective cohort study of 2,096 patients diagnosed with acute PE. The characteristics were recorded at presentation. Treatment was at the discretion of patients’ physicians. The primary study outcome, all-cause mortality, and the secondary outcomes of PE-specific mortality, recurrent venous thromboembolism, and major bleeding were assessed during the first month of follow-up after PE diagnosis.

Results

Overall, the women were older than the men and had significantly higher rates of immobilization. They had significantly lower rates of chronic obstructive pulmonary disease and cancer. Women had a higher prevalence of syncope and elevated brain natriuretic peptide levels. Thirty-day all-cause mortality was similar between women and men (7.1% versus 6.2%; P = 0.38). Male gender was not independently significantly associated with PE-related death (adjusted odds ratio [OR] 1.02; 95% CI, 0.50 to 2.07; P = 0.96). Restricting the analyses to haemodynamically stable patients (n = 2,021), female gender was an independent predictor of all-cause (adjusted OR 1.56; 95% CI, 1.07 to 2.28; P = 0.02) and PE-specific mortality (adjusted OR 1.85; 95% CI, 1.02 to 3.33; P = 0.04). Compared with men, women were 2.05 times more likely to experience a major bleed.

Conclusions

Women and men with PE had different clinical characteristics, presentation, and outcomes. Women receiving anticoagulation have a significantly higher risk of major bleeding, suggesting the need for careful monitoring of anticoagulant intensity in women.

Assessment of right ventricular function in acute pulmonary embolism

The optimal approach to assess right ventricular (RV) function in patients with acute symptomatic pulmonary embolism (PE) lacks clarity.

METHODS

This study aimed to evaluate the optimal approach to assess RV function in normotensive patients with acute symptomatic PE. Outcomes assessed through 30-days after the diagnosis of PE included all-cause mortality and complicated course.

RESULTS

Eight hundred forty-eight patients were enrolled. Multidetector computed tomography (MDCT) and transthoracic echocardiography agreed on the presence or absence of RV overload in 449 (53%) patients. The combination of the simplified Pulmonary Embolism Severity Index (sPESI) and MDCT showed a negative predictive value for 30-day all-cause mortality of 100%. Of the 43% that had an sPESI of >0 points and MDCT RV enlargement, 41 (11.3%) experienced a complicated course that included 24 (6.6%) deaths. One hundred twenty-nine patients (15%) had an sPESI of >0 points, MDCT, and echocardiographic RV overload. Of these, 21 (16.3%) experienced a complicated course within the first 30days, and 10 (7.7%) of them died.

CONCLUSIONS

Incorporation of echocardiographic RV overload to the sPESI and MDCT did not improve identification of low-risk PE patients, whereas it improved identification of those at intermediate-high risk for short-term complications.

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.

Risk stratification of patients with acute symptomatic pulmonary embolism

Patients with acute symptomatic pulmonary embolism (PE) who present with arterial hypotension or shock have a high risk of death (high-risk PE), and treatment guidelines recommend strong consideration of thrombolysis in this setting. For normotensive patients diagnosed with PE, risk stratification should aim to differentiate the group of patients deemed as having a low risk for early complications (all-cause mortality, recurrent venous thromboembolism, and major bleeding) (low-risk PE) from the group of patients at higher risk for PE-related complications (intermediate-high risk PE), so low-risk patients could undergo consideration of early outpatient treatment of PE and intermediate-high risk patients would undergo close observation and consideration of thrombolysis. Clinicians should also use risk stratification and eligibility criteria to identify a third group of patients that should not undergo escalated or home therapy (intermediate-low risk PE). Such patients should initiate standard therapy of PE while in the hospital. Clinical models [e.g., Pulmonary Embolism Severity Index (PESI), simplified PESI (sPESI)] may accurately identify those at low risk of dying shortly after the diagnosis of PE. For identification of intermediate-high risk patients with acute PE, studies have validated predictive models that use a combination of clinical, laboratory and imaging variables.

Evaluation factors of pulmonary embolism severity and prognosis

Management of pulmonary embolism (PE) is still unclear. We summarized 16 kinds of evaluation factors of PE severity and prognosis, and we analyzed the single and joint value for short-term and long-term prognosis. Among them, biomarkers such as brain natriuretic peptide or N-terminal probrain natriuretic peptide, troponin, and heart-type fatty acid-binding protein are the best indicators of PE severity and short-term prognosis. They might replace imaging detections in evaluating PE severity. But the positive predictive value of all the biomarkers is low, and we need to improve each value through joint detection. The PE severity index and simplified PE severity index are more suitable for evaluating the overall risk and long-term prognosis. They could be used as complements of indicators of the PE severity, especially in identifying low-risk group. Integrated risk stratification and strategies of management should be established based on the 2 aspects mentioned previously.

Validation of two clinical prognostic models in patients with acute symptomatic pulmonary embolism

OBJECTIVE

The aim of this study was to compare the predictive value of two clinical prognostic models, the Spanish score and the simplified Pulmonary Embolism Severity Index (sPESI), in an independent cohort of patients diagnosed of acute symptomatic pulmonary embolism (PE).

METHODS

We performed a retrospective analysis of a cohort composed of 1447patients with acute symptomatic PE. The Spanish score and the sPESI were calculated for each patient according to different clinical variables. We assessed the predictive accuracy of these scores for 30-day mortality, and a composite of non fatal recurrent venous thromboembolism and non fatal major bleeding, using Cstatistic, which was obtained by means of logistic regression and ROC curves.

RESULTS

Overall, 138 patients died (9.5%) during the first month of follow-up. Both scores showed an excellent predictive value for 30-day all-cause mortality (Cstatistic, 0.72 and 0.74), but the performance was poor for the secondary endpoint (Cstatistic, 0.60 and 0.59). The sPESI classified fewer patients as low risk (32% versus 62%; P<.001). Low-risk patients based on the sPESI had a lower 30-day mortality than those based on the Spanish score (1.1% versus 4.2%), while the 30-day rate of non fatal recurrent VTE or major bleeding was similar (2.2% versus 2.3%).

CONCLUSIONS

Both scores provide excellent information to stratify the risk of mortality in patients treated of PE. The usefulness of these models for nonfatal adverse events is questionable. The sPESI identified low-risk patients with PE better than the Spanish score.

The prognostic value of pulmonary embolism severity index in acute pulmonary embolism: a meta-analysis

BACKGROUND

Prognostic assessment is important for the management of patients with acute pulmonary embolism (APE). Pulmonary Embolism Severity Index (PESI) and simple PESI (sPESI) are new emerged prognostic assessment tools for APE. The aim of this meta-analysis is to assess the accuracy of the PESI and the sPESI to predict prognostic outcomes (all-cause and PE-related mortality, serious adverse events) in APE patients, and compare between these two PESIs.

METHODS

MEDLINE and EMBASE database were searched up to June 2012 using the terms "Pulmonary Embolism Severity Index" and "pulmonary embolism". Summary odds ratio (OR) with 95% confidence intervals (CIs) for prognostic outcomes in low risk PESI versus high risk PESI were calculated. Summary receiver operating characteristic curve (SROC) used to estimate overall predicting accuracies of prognostic outcomes.

RESULTS

Twenty-one studies were included in this meta-analysis. The results showed low-risk PESI was significantly associated with lower all-cause mortality (OR 0.13; 95% CI 0.12 to 0.15), PE-related mortality (OR 0.09; 95% CI 0.05 to 0.17) and serious adverse events (OR 0.34; 95% CI 0.29 to 0.41), with no homogeneity across studies. In sPESI subgroup, the OR of all-cause mortality, PE-related mortality, and serious adverse events was 0.10 (95% CI 0.08 to 0.14), 0.09 (95% CI 0.03 to 0.26) and 0.40 (95% CI 0.31 to 0.51), respectively; while in PESI subgroup, the OR was 0.14 (95% CI 0.13 to 0.16), 0.09 (95% CI 0.04 to 0.21), and 0.30 (95% CI 0.23 to 0.38), respectively. For accuracy analysis, the pooled sensitivity, the pooled specificity, and the overall weighted AUC for PESI predicting all-cause mortality was 0.909 (95% CI: 0.900 to 0.916), 0.411 (95% CI: 0.407 to 0.415), and 0.7853±0.0058, respectively; for PE-related mortality, it was 0.953 (95% CI: 0.913 to 0.978), 0.374 (95% CI: 0.360 to 0.388), and 0.8218±0.0349, respectively; for serious adverse events, it was 0.821 (95% CI: 0.795 to 0.845), 0.389 (95% CI: 0.384 to 0.394), and 0.6809±0.0208, respectively. In sPESI subgroup, the AUC for predicting all-cause mortality, PE-related mortality, and serious adverse events was 0.7920±0.0117, 0.8317±0.0547, and 0.6454±0.0197, respectively. In PESI subgroup, the AUC was 0.7856±0.0075, 0.8158±0.0451, and 0.6609±0.0252, respectively.

CONCLUSIONS

PESI has discriminative power to predict the short-term death and adverse outcome events in patients with acute pulmonary embolism, the PESI and the sPESI have similar accuracy, while sPESI is easier to use. However, the calibration for predicting prognosis can't be calculated from this meta-analysis, some prospective studies for accessing PESI predicting calibration can be recommended.

Venous thromboembolism: epidemiology and magnitude of the problem

Pulmonary embolism is the third most common cardiovascular disease after myocardial infarction and stroke. The death rate from pulmonary embolism exceeds the death rate from myocardial infarction, because myocardial infarction is much easier to detect and to treat. Among survivors of pulmonary embolism, chronic thromboembolic pulmonary hypertension occurs in 2-4 of every 100 patients. Post-thrombotic syndrome of the legs, characterized by chronic venous insufficiency, occurs in up to half of patients who suffer deep vein thrombosis or pulmonary embolism. We have effective pharmacological regimens using fixed low dose unfractionated or low molecular weight heparin to prevent venous thromboembolism among hospitalized patients. There remains the problem of low rates of utilization of pharmacological prophylaxis. The biggest change in our understanding of the epidemiology of venous thromboembolism is that we now believe that deep vein thrombosis and pulmonary embolism share similar risk factors and pathophysiology with atherothrombosis and coronary artery disease.