Oxygen saturation or respiratory rate to improve risk stratification in hemodynamically stable patients with acute pulmonary embolism

Development and external validation of a nomogram for predicting short-term prognosis in patients with acute pulmonary embolism

BACKGROUND

Accurate assessment and timely intervention play a crucial role in ameliorating poor short-term prognosis of acute pulmonary embolism (APE) patients. The currently employed scoring models exhibit a degree of complexity, and some models may not comprehensively incorporate relevant indicators, thereby imposing limitations on the evaluative efficacy. Our study aimed to construct and externally validate a nomogram that predicts 30-day all-cause mortality risk in APE patients.

METHODS

Clinical data from APE patients in Intensive Care-IV database was included as a training cohort. Additionally, we utilized our hospital's APE database as an external validation cohort. The nomogram was developed, and its predictive ability was evaluated using receiver operating characteristic (ROC) curves, calibration plots and decision curve analysis.

RESULTS

A collective of 1332 patients and 336 patients were respectively enrolled as the training cohort and the validation cohort in this study. Five variables including age, malignancy, oxygen saturation, blood glucose, and the use of vasopressor, were identified based on the results of the multivariate Cox regression model. The ROC value for the nomogram in the training cohort yielded 0.765, whereas in the validation group, it reached 0.907. Notably, these values surpassed the corresponding ROC values for the Pulmonary Embolism Severity Index, which were 0.713 in the training cohort and 0.754 in the validation cohort.

CONCLUSIONS

The nomogram including five indicators had a good performance in predicting short-term prognosis in patients with APE, which was easier to apply and provided better recommendations for clinical decision-making.

Short- and Long-Term Prognosis in Hemodynamically Stable Pulmonary Embolism With Unresectable or Metastatic Malignancies: The Role of Performance Status

BACKGROUND

The simplified Pulmonary Embolism Severity Index (sPESI) has limitations when evaluating acute pulmonary embolism (PE) in patients with concurrent malignancy. Despite its utility in predicting outcomes among cancer patients, the role of the Eastern Cooperative Oncology Group Performance Status (ECOG PS) in acute PE remains underexplored. This study aims to assess the prognostic significance of ECOG PS ≥ 3 on short- and long-term mortality in acute PE with malignancy, correlating it with the sPESI.

METHODS AND RESULTS

We retrospectively analyzed 44 hemodynamically stable acute PE patients with unresectable or metastatic malignancies ineligible for curative treatment at Kameda Medical Center, a tertiary medical facility in Japan, from April 1, 2019, to March 2, 2023. Of these patients, 16 (36.4%) had ECOG PS ≥ 3. No 30-day mortality occurred in patients with ECOG PS ≤ 2, compared to 18.8% in those with ECOG PS ≥ 3 (p = 0.04). Groups were similar in the sPESI scores, hospital-onset PE proportion, and initial treatments. Post PE diagnosis, 92.9% of ECOG PS ≤ 2 patients and 50% of ECOG PS ≥ 3 patients received chemotherapy (p = 0.002). Cox regression analysis revealed ECOG PS ≥ 3 was independently associated with increased overall survival hazard (adjusted HR = 4.0; P = 0.002).

CONCLUSIONS

ECOG PS ≥ 3 suggests a poorer short-term prognosis and independently predicts a worse long-term prognosis in hemodynamically stable acute PE patients with advanced malignancies.

Performance of the Simplified Pulmonary Embolism Severity Index in predicting 30-day mortality after acute pulmonary embolism: Validation from a large-scale cohort

BACKGROUND

The performance of existing prognostic scores including the simplified Pulmonary Embolism Severity Index (sPESI) for short-term mortality of non-high-risk PE in Chinese population has not been widely validated.

METHODS

Non-high-risk patients were included from the prospective cohort of the China pUlmonary Thromboembolism REgistry Study (CURES). The sPESI, RIETE, Geneva, modified FAST, and Bova score were validated. The discriminatory performance was measured by the area under the curve (AUC). We also compared the sensitivity, odds ratio, specificity, positive predictive value and negative predictive value of these scores.

RESULTS

A total of 6,873 non-high-risk patients with acute PE were included and 241 (3.5 %) patients died within 30 days. Compared to the Geneva, modified FAST, and Bova score, the AUCs for predicting 30-day death of sPESI and RIETE score were higher at 0.712 (95 % CI, 0.680, 0.743) and 0.723 (95 % CI, 0.691, 0.755) respectively. The sPESI demonstrated the highest sensitivity at 0.809, while the RIETE score, Geneva, Modified FAST and BOVA score showed sensitivities of 0.622, 0.568, 0.477 and 0.502 respectively. A sPESI ⩾1 point was associated with a 4.7-fold increased risk of 30-day all-cause mortality (95 % CI, 3.427, 6.563, p < 0.001), while a RIETE score of ⩾1 point was associated with a 4.5-fold increased risk (95 % CI, 3.127, 6.341, p < 0.001). The Geneva score, modified FAST and Bova score showed inferior performance.

CONCLUSIONS

The implementation of the fewer-parameter, easier-to-calculate sPESI in Chinese patients with PE can help to discriminate patients with extremely low risk of short-term mortality for home treatment or early discharge.

Recombinant hirudin attenuates pulmonary hypertension and thrombosis in acute pulmonary embolism rat model

Background

Acute pulmonary embolism (APE) is classified as a subset of diseases that are characterized by lung obstruction due to various types of emboli. Current clinical APE treatment using anticoagulants is frequently accompanied by high risk of bleeding complications. Recombinant hirudin (R-hirudin) has been found to have antithrombotic properties. However, the specific impact of R-hirudin on APE remains unknown.

Methods

Sprague-Dawley (SD) rats were randomly assigned to five groups, with thrombi injections to establish APE models. Control and APE group rats were subcutaneously injected with equal amounts of dimethyl sulfoxide (DMSO). The APE+R-hirudin low-dose, middle-dose, and high-dose groups received subcutaneous injections of hirudin at doses of 0.25 mg/kg, 0.5 mg/kg, and 1.0 mg/kg, respectively. Each group was subdivided into time points of 2 h, 6 h, 1 d, and 4 d, with five animals per point. Subsequently, all rats were euthanized, and serum and lung tissues were collected. Following the assessment of right ventricular pressure (RVP) and mean pulmonary artery pressure (mPAP), blood gas analysis, enzyme-linked immunosorbnent assay (ELISA), pulmonary artery vascular testing, hematoxylin-eosin (HE) staining, Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, immunohistochemistry, and Western blot experiments were conducted.

Results

R-hirudin treatment caused a significant reduction of mPAP, RVP, and Malondialdehyde (MDA) content, as well as H2O2 and myeloperoxidase (MPO) activity, while increasing pressure of oxygen (PaO2) and Superoxide Dismutase (SOD) activity. R-hirudin also decreased wall area ratio and wall thickness to diameter ratio in APE rat pulmonary arteries. Serum levels of endothelin-1 (ET-1) and thromboxaneB2 (TXB2) decreased, while prostaglandin (6-K-PGF1α) and NO levels increased. Moreover, R-hirudin ameliorated histopathological injuries and reduced apoptotic cells and Matrix metalloproteinase-9 (MMP9), vascular cell adhesion molecule-1 (VCAM-1), p-Extracellular signal-regulated kinase (ERK)1/2/ERK1/2, and p-P65/P65 expression in lung tissues.

Conclusion

R-hirudin attenuated pulmonary hypertension and thrombosis in APE rats, suggesting its potential as a novel treatment strategy for APE.

Identifying prognostic factors for pulmonary embolism patients with hemodynamic decompensation admitted to the intensive care unit

We aimed to determine prognostic indicators of PE patients with hemodynamic decompensation admitted to the ICU. PE patients with hemodynamic decompensation at ICU admission from Medical Information Mart for Intensive Care IV database were included. Least absolute shrinkage and selection operator with 2 specific lambdas were performed to reduce the dimension of variables after univariate analysis. Then we conducted multivariate logistic regression analysis and 2 models were built. A total of 548 patients were included, among whom 187 died. Lactate, creatine-kinase MB, troponin-T were significantly higher in death group. Eight common factors were screened out from first model statistically mostly in consistent with second model: older age, decreased hemoglobin, elevated anion gap, elevated International Standard Ratio (INR), elevated respiratory rate, decreased temperature, decreased blood oxygen saturation (SpO2) and the onset of cardiac arrest were significantly risk factors for in-Hospital mortality. The nonlinear relationships between these indicators and mortality were showed by the restricted cubic spline and cutoff values were determined. Our study demonstrated that age, hemoglobin levels, anion gap levels, INR, respiratory rate, temperature, SpO2 levels, the onset of cardiac arrest could be applied to predict mortality of PE patients with hemodynamic decompensation at ICU admission.

The Predictive Value of the MELD Scores for In-Hospital Adverse Events in Normotensive Patients with Acute Pulmonary Embolism

The model for end-stage liver disease (MELD) and the model for end-stage liver disease excluding international normalized ratio (INR) (MELD-XI) scores, which reflect dysfunction of liver and kidneys, have been reported to be related to the prognosis of patients with right-sided "backward" failure. However, the relationship between the MELD/MELD-XI score and the in-hospital adverse events in pulmonary embolism (PE) patients was unknown. Normotensive PE patients were retrospectively enrolled at China-Japan friendship hospital from January 2017 to February 2020. The primary outcome was defined as death and clinical deterioration during hospitalization. Multivariate logistic analysis was used to explore the association between the MELD and MELD-XI scores for in-hospital adverse events. We also compared the accuracy of the MELD, MELD-XI, and the pulmonary embolism severity index (PESI) score using the time-dependent receiver operating characteristic curve and corresponding areas under the curve (AUC). A total of 222 PE patients were analyzed. Logistic regression analysis showed that the MELD score was independently associated with in-hospital adverse events (odds ratio = 1.115, 95% confidential interval = 1.022-1.217, P = .014). The MELD score has an AUC of 0.731 and was better than PESI (AUC of 0.629) in predicting in-hospital adverse events. Among PE patients with normal blood pressure on admission, the MELD score was associated with increased in-hospital adverse events.

Prediction of in-hospital adverse clinical outcomes in patients with pulmonary thromboembolism, machine learning based models

Background

Pulmonary thromboembolism (PE) is the third leading cause of cardiovascular events. The conventional modeling methods and severity risk scores lack multiple laboratories, paraclinical and imaging data. Data science and machine learning (ML) based prediction models may help better predict outcomes.

Materials and methods

In this retrospective registry-based design, all consecutive hospitalized patients diagnosed with pulmonary thromboembolism (based on pulmonary CT angiography) from 2011 to 2019 were recruited. ML based algorithms [Gradient Boosting (GB) and Deep Learning (DL)] were applied and compared with logistic regression (LR) to predict hemodynamic instability and/or all-cause mortality.

Results

A total number of 1,017 patients were finally enrolled in the study, including 465 women and 552 men. Overall incidence of study main endpoint was 9.6%, (7.2% in men and 12.4% in women; p-value = 0.05). The overall performance of the GB model is better than the other two models (AUC: 0.94 for GB vs. 0.88 and 0.90 for DL and LR models respectively). Based on GB model, lower O2 saturation and right ventricle dilation and dysfunction were among the strongest adverse event predictors.

Conclusion

ML-based models have notable prediction ability in PE patients. These algorithms may help physicians to detect high-risk patients earlier and take appropriate preventive measures.

Arterial partial pressure of oxygen and diffusion function as prognostic biomarkers for acute pulmonary embolism

BACKGROUND

Risk stratification for acute pulmonary embolism (PE) ignores the roles of respiratory function and gas exchange. We aimed to identify the role of arterial partial pressure of oxygen (PO2) and diffusion function as prognostic biomarkers.

METHODS

We collected the data from hospitalised patients with acute PE. We used Spearman's correlation coefficient and Cox regression analysis to explore the clinical and prognostic values of PO2 and predicted percentage diffusing lung capacity for carbon monoxide (DLCO%pred) to predict the 30-day mortality.

RESULTS

We included 309 patients (mean age: 67.93 ± 13.31 years); 46.6% were men, and 12.62% were haemodynamically unstable. The 30-day all-cause mortality rates in the high-, intermediate high-, intermediate low-, and low-risk groups were 7.7%, 4.7%, 2.9%, and 0.0%, respectively (P < 0.05). PO2 (P = 0.012) and DLCO%pred (P = 0.036) were significantly different between the four risk groups. There were strong correlations between PO2, DLCO%pred, PO2*DLCO%pred, and other markers (P < 0.05), especially troponin I, N-terminal pro-brain natriuretic peptide, and systolic pulmonary artery pressure. PO2 and PO2*DLCO%pred were prognostic factors for death in haemodynamically stable patients (hazard ratio [HR] 0.618, 95% confidence interval [CI] 0.389-0.980, P = 0.041, and HR 0.501, 95% CI 0.26-0.96, P = 0.036, respectively). A lower PO2 (<8 kPa) was associated with a higher risk of mortality in all patients and in haemodynamically stable ones (HR 9.462, 95% CI 2.365-37.860, P = 0.001, and HR 6.597, 95% CI 1.102-39.495, P = 0.039, respectively).

CONCLUSIONS

PO2, PO2*DLCO%pred, and PO2 < 8 kPa were predictors of 30-day all-cause mortality in all patients and haemodynamically stable ones.

TRIAL REGISTRATION

ChiCTR2000030448.

Rapid prediction of deterioration risk among non-high-risk patients with acute pulmonary embolism at admission: An imaging tool

BACKGROUND

Computed tomography (CT) pulmonary angiography as the first-line diagnosis tool of acute pulmonary embolism (PE), might improve this discriminatory power. We aimed to developed a simply tool combining multi-CT parameters to complete individualized risk assessment of deterioration in non-high-risk patients with acute PE at admission.

METHOD

Consecutive non-high-risk patients with acute PE who were treated in a Chinese center during 2010-2021, were collected.Prognosis-related CT parameters were reviewed. Deterioration was defined as any adverse event within 30 day after admission. Eligible patients were randomized into derivation and validation cohorts. In the derivation cohort, CT parameters were screened for importance using classification tree methodology and enrolled variables was partitioned via curve-fitting and dose-response analysis. A nomogram was developed and the predictive power in both cohorts was evaluated based on the area under the receiver operating characteristic curve (AUROC) and the corresponding 95% confidence interval (CI).

RESULT

A total of 1001 patients were included. The preliminary analyses revealed that deterioration risk was related to the right-to-left ventricular diameter ratio at 4-chamber view, pulmonary vein filling abnormality. After a curve-fitting to deterioration risk, these parameters were partitioned and used to develop a nomogram, which had AUROC values of 0.91 (95% CI: 0.87-0.96) in the derivation cohort and 0.89 (95% CI: 0.81-0.97) in the validation cohort. A web-based version of the radiomics scoring tool was published online for use in clinical practice (https://acutepeprediction.shinyapps.io/Radiomics_Predictive_Tool/).

CONCLUSION

This simply tool can complete rapid estimation of deterioration risk among non-high-risk acute PE patients at admission.

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.

Overview of Management of Intermediate- and High-Risk Pulmonary Embolism

Anticoagulation is the cornerstone of acute pulmonary embolism (PE) therapy. Intermediate-risk (submassive) or high-risk (massive) PE patients have higher mortality than low-risk patients. It is generally accepted that high-risk PE patients should be considered for more aggressive therapy. Intermediate-risk patients can be subdivided, although more than simply categorizing the patient is required to guide therapy. Therapeutic approaches depend on a prompt, detailed evaluation, and PE response teams may help with rapid assessment and initiation of therapy. More clinical trial data are needed to guide clinicians in the management of acute intermediate- and high-risk PE patients.

Prognostic value of respiratory index in haemodynamically stable patients with acute pulmonary embolism: The Respiratory Index model study

Background:

Current strategies for prognostic stratification in haemodynamically stable patients with acute pulmonary embolism require improvement. The aims of this study in haemodynamically stable patients with acute pulmonary embolism were (a) to evaluate the prognostic value of a novel respiratory index (oxygen saturation in air to respiratory rate ratio) and (b) to derive a risk model which includes the respiratory index and evaluate its value in predicting 30-day mortality.

Methods:

Prospective cohorts of haemodynamically stable patients with acute pulmonary embolism were merged to a collaborative database that served to create two subsequent derivation and validation cohorts based on a temporal criterion. The study outcome was 30-day all-cause death.

Results:

Thirty-day all-cause death occurred in 7.5% and in 6.9% of patients in the derivation and validation cohorts (each composed of 319 patients). In the derivation cohort, the respiratory index (odds ratio 0.66, 95% confidence interval 0.48–0.90) and simplified Pulmonary Embolism Severity Index (odds ratio 9.16, 95% confidence interval 1.22–68.89) were predictors of 30-day mortality. The cut-off value of the respiratory index ⩽3.8 was identified to best predict 30-day all-cause death (15.4% vs 5.0%, odds ratio 2.94, 95% confidence interval 1.22–7.11). The respiratory index ⩽3.8 was combined with the simplified Pulmonary Embolism Severity Index to create the Respiratory Index model that showed a good discriminatory power in the derivation (c-statistic 0.703, 95% confidence interval 0.60–0.80) and in the validation cohort (c-statistic 0.838, 95% confidence interval 0.768–0.907).

Conclusion:

In hemodynamically stable patients with acute pulmonary embolism, the respiratory index was an independent predictor of 30-day all-cause death. The Respiratory Index model which includes the simplified Pulmonary Embolism Severity Index and the respiratory index, provides a good risk stratification of haemodynamically stable patients with acute pulmonary embolism.

The predictive value of PaO2/FIO2 and additional parameters for in-hospital mortality in patients with acute pulmonary embolism: an 8-year prospective observational single-center cohort study

BACKGROUND

Rapid stratification and appropriate treatment on admission are critical to saving lives of patients with acute pulmonary embolism (PE). None of the clinical prediction tools perform well when applied to all patients with acute PE. It may be important to integrate respiratory features into the 2014 European Society of Cardiology model. First, we aimed to assess the relationship between the arterial partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FIO₂) ratio and in-hospital mortality, determine the optimal cutoff value of PaO₂/FIO₂, and determine if this value, which is quick and easy to obtain on admission, is a predictor of in-hospital mortality in this population. Second, we aimed to evaluate the potential additional determinants including laboratory parameters that may affect the in-hospital mortality. We hypothesized that the PaO2/FiO2 ratio would be a clinical prediction tool for in-hospital mortality in patients with acute PE.

METHODS

A prospective single-center observational cohort study was conducted in Beijing Hospital from January 2010 to November 2017. Arterial blood gas analysis data captured on admission, clinical characteristics, risk factors, laboratory data, imaging findings, and in-hospital mortality were compared between survivors and non-survivors. The area under the receiver operating characteristic curve (AUC) for in-hospital mortality based on the PaO₂/FiO₂ value was determined, and the association between the parameters and in-hospital mortality was analyzed by using logistic regression analysis.

RESULTS

Body mass index, history of cancer, PaO₂/FiO₂ value, pulse rate, cardiac troponin I level, lactate dehydrogenase level, white blood cell count, D-dimer level, and risk stratification measurements differed between survivors and non-survivors. The optimal cutoff value of PaO₂/FiO₂ for predicting mortality was 265 (AUC = 0.765, P < 0.001). Only a PaO₂/FiO₂ ratio < 265 (95% confidence interval [CI] 1.823-21.483, P = 0.004), history of cancer (95% CI 1.161-15.927, P = 0.029), and risk stratification (95% CI 1.047-16.957, P = 0.043) continued to be associated with an increased risk of in-hospital mortality of acute PE.

CONCLUSION

A simple determination of the PaO₂/FiO₂ ratio at <265 may provide important information on admission about patients' in-hospital prognosis, and PaO₂/FiO₂ ratio < 265, history of cancer, and risk stratification are predictors of in-hospital mortality of acute PE.