National trends and outcomes for extra-corporeal membrane oxygenation use in high-risk pulmonary embolism

Thrombolysis and extracorporeal cardiopulmonary resuscitation for cardiac arrest due to pulmonary embolism: A case report

BACKGROUND

Cardiac arrest caused by acute pulmonary embolism (PE) is the most serious clinical circumstance, necessitating rapid identification, immediate cardiopulmonary resuscitation (CPR), and systemic thrombolytic therapy. Extracorporeal CPR (ECPR) is typically employed as a rescue therapy for selected patients when conventional CPR is failing in settings where it can be implemented.

CASE SUMMARY

We present a case of a 69-year-old male who experienced a prolonged cardiac arrest in an ambulance with pulseless electrical activity. Upon arrival at the emergency department with ongoing manual chest compressions, bedside point-of-care ultrasound revealed an enlarged right ventricle without contractility. Acute PE was suspected as the cause of cardiac arrest, and intravenous thrombolytic therapy with 50 mg tissue plasminogen activator was administered during mechanical chest compressions. Despite 31 minutes of CPR, return of spontaneous circulation was not achieved until 8 minutes after initiation of Veno-arterial extracorporeal membrane oxygenation (ECMO) support. Under ECMO support, the hemodynamic status and myocardial contractility significantly improved. However, the patient ultimately did not survive due to intracerebral hemorrhagic complications, leading to death a few days later in the hospital.

CONCLUSION

This case illustrates the potential of combining systemic thrombolysis with ECPR for refractory cardiac arrest caused by acute PE, but it also highlights the increased risk of significant bleeding complications, including fatal intracranial hemorrhage.

Mechanical Circulatory Support for Massive Pulmonary Embolism

Up to 50% of patients with pulmonary embolism (PE) experience hemodynamic instability and approximately 70% of patients who die of PE experience an accelerated cascade of symptoms within the first hours of onset of symptoms, thus necessitating rapid evaluation and intervention. Venoarterial extracorporeal membrane oxygenation and other ventricular assist devices, depending on the hemodynamic derangements present, may be used to stabilize patients with massive PE refractory to initial therapies or with contraindications to other interventions. Given the abnormalities in both pulmonary circulation and gas exchange caused by massive PE, venoarterial extracorporeal membrane oxygenation may be considered the preferred form of mechanical circulatory support for most patients. Venoarterial extracorporeal membrane oxygenation unloads the right ventricle and improves oxygenation, which may not only help buy time until definitive treatment but may also reduce myocardial ischemia and myocardial dysfunction. This review summarizes the available clinical data on the use of mechanical circulatory support, especially venoarterial extracorporeal membrane oxygenation, in the treatment of patients with massive PE. Furthermore, this review also provides practical guidance on the implementation of this strategy in clinical practice.

Sex Differences in Advanced Therapeutic Interventions for Intermediate- and High-Risk Pulmonary Embolism

PURPOSE

Advanced interventions are increasingly used to treat intermediate- and high-risk acute pulmonary embolism (PE). While sex-based differences exist in treatment of other diseases, it is unknown whether these disparities extend to PE.

METHODS

This is a secondary analysis of a prospective cohort study of adult patients diagnosed with radiographically confirmed intermediate- and high-risk acute PE at a tertiary hospital between 1/1/2012 and 12/31/2021 for whom the PE Response Team was activated. Primary outcome was receipt of any advanced intervention. Descriptive and inferential analyses using Chi-square tests, t tests, and logistic regression were performed to evaluate for factors associated with the primary outcome.

FINDINGS

We analyzed 902 patients, of whom 439 (49%) were female. Although women were more likely to present with right heart strain on echo (78.6% vs 71.1% P = 0.012) and elevated NT-proBNP (69.2% vs 55.7% P < 0.001), there was no significant sex-based difference in clinical PE severity, defined as intermediate- versus high-risk, at presentation. Primary outcome did not differ significantly by sex (18.7% vs 23.5% P = 0.129). In multivariate models, high-risk PE decreased odds of receiving an advanced therapy (0.50 [0.31, 0.79] P = 0.003), while receiving assisted ventilation (4.70 [2.90, 7.62], P < 0.001) and full code status (4.18 [1.60, 10.91], P = 0.003) increased odds.

IMPLICATIONS

This study adds to the scant literature on sex differences in interventions for acute PE. Significant baseline variation exists between female and male patients presenting with acute PE. Clinical factors were predictive of receiving advanced PE therapies, while sex was not.

Clinical characteristics and short-term outcomes of patients with critical acute pulmonary embolism requiring extracorporeal membrane oxygenation: from the COMMAND VTE Registry-2

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) might be required as a treatment option in patients with critical pulmonary embolism (PE). However, the clinical features and outcomes of the use of ECMO for critical acute PE are still limited. The present study aimed to clarify the clinical characteristics, management strategies and outcomes of patients with acute PE requiring ECMO in the current era using data from a large-scale observational database.

METHODS

We analyzed the data of the COMMAND VTE Registry-2: a physician-initiated, multicenter, retrospective cohort study enrolling consecutive patients with acute symptomatic venous thromboembolism (VTE). Among 2035 patients with acute symptomatic PE, there were 76 patients (3.7%) requiring ECMO.

RESULTS

Overall, the mean age was 58.4 years, and 34 patients (44.7%) were men. Cardiac arrest or circulatory collapse at diagnosis was reported in 67 patients (88.2%). The 30-day incidence of all-cause death was 30.3%, which were all PE-related deaths. The 30-day incidence of major bleeding was 54.0%, and the vast majority of bleedings were procedure site-related bleeding events and surgery-related bleeding (22.4%). The 30-day incidence of all-cause death was 6.3% in 16 patients with surgical intervention, 43.8% in 16 patients with catheter intervention, 25.0% in 16 patients with thrombolytic therapy, and 39.3% in 28 patients with anticoagulation only.

CONCLUSIONS

The current large real-world VTE registry in Japan revealed clinical features and outcomes of critical acute PE requiring ECMO in the current era, which suggested several unmet needs for future clinical trials.

Extracorporeal Membrane Oxygenation and Reperfusion Strategies in High-Risk Pulmonary Embolism Hospitalizations

OBJECTIVES

To investigate the contemporary use of extracorporeal membrane oxygenation (ECMO) in conjunction with reperfusion strategies in high-risk pulmonary embolism (PE).

DESIGN

Observational epidemiological analysis.

SETTING

The U.S. Nationwide Inpatient Sample (NIS) (years 2016-2020).

PATIENTS

High-risk PE hospitalizations.

MEASUREMENTS AND MAIN RESULTS

Use of ECMO in conjunction with thrombolysis-based reperfusion (systemic thrombolysis or catheter-directed thrombolysis) or mechanical reperfusion (surgical embolectomy or catheter-based thrombectomy) with regards to in-hospital mortality and major bleeding. We identified high-risk PE hospitalizations in the NIS (years 2016-2020) and investigated the use of ECMO in conjunction with thrombolysis-based (systemic thrombolysis or catheter-directed thrombolysis) and mechanical (surgical embolectomy or catheter-based thrombectomy) reperfusion strategies with regards to in-hospital mortality and major bleeding. Among 122,735 hospitalizations for high-risk PE, ECMO was used in 2,805 (2.3%); stand-alone in 1.4%, thrombolysis-based reperfusion in 0.4%, and mechanical reperfusion in 0.5%. Compared with neither reperfusion nor ECMO, ECMO plus thrombolysis-based reperfusion was associated with reduced in-hospital mortality (adjusted odds ratio [aOR] 0.61; 95% CI, 0.38-0.98), whereas no difference was found with ECMO plus mechanical reperfusion (aOR 1.03; 95% CI, 0.67-1.60), and ECMO stand-alone was associated with increased in-hospital mortality (aOR 1.60; 95% CI, 1.22-2.10). In the cardiac arrest subgroup, ECMO was associated with reduced in-hospital mortality (aOR 0.71; 95% CI, 0.53-0.93). Among all patients on ECMO, thrombolysis-based reperfusion was significantly associated (aOR 0.55; 95% CI, 0.33-0.91), and mechanical reperfusion showed a trend (aOR 0.75; 95% CI, 0.47-1.19) toward reduced in-hospital mortality compared with no reperfusion, without increases in major bleeding.

CONCLUSIONS

In patients with high-risk PE and refractory hemodynamic instability, ECMO may be a valuable supportive treatment in conjunction with reperfusion treatment but not as a stand-alone treatment especially for patients suffering from cardiac arrest.

Should Obesity Be an Exclusion Criterion for Extracorporeal Membrane Oxygenation Support? A Scoping Review

Obesity is often considered a contraindication to extracorporeal membrane oxygenation (ECMO) candidacy due to technical challenges with vascular access, higher cardiac output requirements, and known associations between obesity and overall increased morbidity and mortality due to chronic health conditions. However, a growing body of literature suggests that ECMO may be as safe and efficacious in both obese and nonobese patients. This scoping review provides a synthesis of the available literature on the outcomes of obese patients supported with (1) venovenous (VV)-ECMO in acute respiratory distress syndrome (ARDS) not due to coronavirus disease 2019 (COVID-19), (2) VV-ECMO in ARDS due to COVID-19, (3) venoarterial (VA)-ECMO for all indications, and (4) studies combining data of patients supported with VA- and VV-ECMO. A librarian-assisted search was performed using 4 primary electronic medical databases (PubMed, Web of Science, Excerpta Medica database [Embase], and Cochrane Library) from January 2003 to March 2023. Articles that reported outcomes of obese patients requiring ECMO support were included. Two reviewers independently screened titles, abstracts, and full text of articles to determine eligibility. Data extraction was performed using customized fields established a priori within a systematic review software system. A total of 354 publications were imported for screening on titles and abstracts, and 30 studies were selected for full-text review. A total of 26 publications met the inclusion criteria: 7 on VV-ECMO support in non-COVID-19 ARDS patients, 6 on ECMO in COVID-19 ARDS patients, 8 in patients supported with VA-ECMO, and 5 combining both VA- and VV-ECMO data. Although the included studies are limited to retrospective analyses and display a heterogeneity in definitions of obesity and comparison groups, the currently available literature suggests that outcomes and complications of ECMO therapy are equivalent in obese patients as compared to nonobese patients. Hence, obesity as measured by body mass index alone should not be considered an exclusion criterion in the decision to initiate ECMO.

Venoarterial Extracorporeal Life Support Use in Acute Pulmonary Embolism Shows Favorable Outcomes

BACKGROUND

Differences in outcomes by indication for venoarterial extracorporeal life support (VA-ECLS) are poorly described. We hypothesized that patients on VA-ECLS for acute pulmonary embolism (PE) have fewer complications and better survival than patients on VA-ECLS for other indications.

METHODS

All patients ≥18 years on VA-ECLS from the Extracorporeal Life Support Organization global registry (2010-2019) were evaluated (n = 29,842). After excluding patients aged >79 years (n = 729) and those with incomplete indication data (n = 2530), patients were stratified by VA-ECLS indication for PE vs all other indications. The association between being discharged alive and each type of complication with VA-ECLS indication was assessed.

RESULTS

Of 26,583 patients included in the analysis, 978 (3.7%) were on VA-ECLS for a primary diagnosis of acute PE. Acute PE patients were younger (53.1 vs 56.7 years, P < .001) and were more likely to be women (52.1% vs 32.3%, P < .001). Patients who underwent VA-ECLS for acute PE were 78% more likely to be discharged alive vs patients supported with VA-ECLS for other reasons (52.8% vs 40.4%; P < .001). Acute PE patients had fewer cardiovascular and renal complications (26.6% vs 38.0% and 31.1% vs 39.4%, respectively; adjusted P < .001). Acute PE patients had higher odds of having clots and mechanical complications (8.7% vs 7.9% and 16.7% vs 14.6%, respectively; adjusted P < .001).

CONCLUSIONS

Patients undergoing VA-ECLS for acute PE have higher odds of survival to hospital discharge compared with those supported for other indications. Additionally, VA-ECLS in this population is associated with fewer cardiovascular and renal complications but higher mechanical complications.

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.

From Trendelenburg to PERTs: Evolution in the Management of Massive Pulmonary Embolism

Massive pulmonary embolism (MPE) is a serious condition affecting the pulmonary arteries and is difficult to diagnose, triage, and treat. The American College of Chest Physicians (AHA) and the European Society of Cardiology (ESC) have different classification approaches for PE, with the AHA defining three subtypes and the ESC four. Misdiagnosis is common, leading to delayed or inadequate treatment. The incidence of PE-related death rates has been increasing over the years, and mortality rates vary depending on the subtype of PE, with MPE having the highest mortality rate. The current definition of MPE originated from early surgical embolectomy cases and discussions among experts. However, this definition fails to capture patients at the point of maximal benefit because it is based on late findings of MPE. Pulmonary Embolism Response Teams (PERTs) have emerged as a fundamental shift in the management of MPE, with a focus on high-risk and MPE cases and a goal of rapidly connecting patients with appropriate therapies based on up-to-date evidence. This review highlights the challenges in diagnosing and managing MPE and emphasizes the importance of PERTs and risk stratification scores in improving outcomes for patients with PE.

Venoarterial Extracorporeal Membrane Oxygenation With or Without Advanced Intervention for Massive Pulmonary Embolism

INTRODUCTION

Massive pulmonary embolism (MPE) is a rare but highly fatal condition. Our study's objective was to evaluate the association between advanced interventions and survival among patients with MPE treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

This is a retrospective review of the Extracorporeal Life Support Organization (ELSO) registry data. We included adult patients with MPE who were treated with VA-ECMO during 2010-2020. Our Primary outcome was survival to hospital discharge; secondary outcomes were ECMO duration among survivors and rates of ECMO-related complications. Clinical variables were compared using the Pearson chi-square and Kruskal-Wallis H tests.

RESULTS

We included 802 patients; 80 (10%) received SPE and 18 (2%) received CDT. Overall, 426 (53%) survived to discharge; survival was not significantly different among those treated with SPE or CDT on VA-ECMO (70%) versus VA-ECMO alone (52%) or SPE or CDT before VA-ECMO (52%). Multivariable regression found a trend towards increased survival among those treated with SPE or CDT while on ECMO (AOR 1.8, 95% CI 0.9-3.6), but no significant correlation. There was no association between advanced interventions and ECMO duration among survivors, or rates of ECMO-related complications.

CONCLUSION

Our study found no difference in survival in patients with MPE who received advanced interventions prior to ECMO, and a slight non-significant benefit in those who received advanced interventions while on ECMO.

Management of high-risk pulmonary embolism in the emergency department: A narrative review

BACKGROUND

High-risk pulmonary embolism (PE) is a complex, life-threatening condition, and emergency clinicians must be ready to resuscitate and rapidly pursue primary reperfusion therapy. The first-line reperfusion therapy for patients with high-risk PE is systemic thrombolytics (ST). Despite consensus guidelines, only a fraction of eligible patients receive ST for high-risk PE.

OBJECTIVE

This review provides emergency clinicians with a comprehensive overview of the current evidence regarding the management of high-risk PE with an emphasis on ST and other reperfusion therapies to address the gap between practice and guideline recommendations.

DISCUSSION

High-risk PE is defined as PE that causes hemodynamic instability. The high mortality rate and dynamic pathophysiology of high-risk PE make it challenging to manage. Initial stabilization of the decompensating patient includes vasopressor administration and supplemental oxygen or high-flow nasal cannula. Primary reperfusion therapy should be pursued for those with high-risk PE, and consensus guidelines recommend the use of ST for high-risk PE based on studies demonstrating benefit. Other options for reperfusion include surgical embolectomy and catheter directed interventions.

CONCLUSIONS

Emergency clinicians must possess an understanding of high-risk PE including the clinical assessment, pathophysiology, management of hemodynamic instability and respiratory failure, and primary reperfusion therapies.

Palliative Care Penetration Among Hospitalizations with Acute Pulmonary Embolism: A Nationwide Analysis

Background: Integration of palliative care in the management of critical illnesses has been linked with a better quality of life for patients and their families. Yet, there is a paucity of data regarding the role of palliative care for acute pulmonary embolism (PE) hospitalizations which is a leading cause of cardiovascular death in the United States. Methods: Using the Nationwide Inpatient Sample years 2005-2015, acute PE hospitalizations were identified by using ICD-9-codes. The primary outcome was the trends of palliative care penetration during acute PE hospitalizations and the main secondary outcome was the factors associated with palliative care utilization. Results: Among 505,485 acute PE hospitalizations, 15,522 (3.1%) had a palliative care encounter. Hospitalizations with high-risk PE versus non-high-risk PE showed a higher utilization for palliative care (7.6% vs. 2.7%, P < 0.001). The annual trends of palliative care penetration among hospitalizations with PE showed a rising pattern (0.6% in 2005 vs. 5.6% in 2015, Ptrend<0.001). A similar trend was observed among those with high-risk PE (0.8% in 2005 vs. 12.8% in 2015, Ptrend<0.001). The trends of palliative care utilization among cancer and non-cancer admissions increased over time (1.3%in 2005 to 15.5% in 2015 vs. 0.5% in 2005 to 3.9% in 2015, both P-trends<0.001). Some racial and regional disparities were identified among the predictors of palliative care utilization. Conclusions: Palliative care penetration among acute PE hospitalizations remains suboptimal even among high-risk PE, and cancer hospitalizations, but has been increasing in recent years. Future studies are needed to investigate the barriers for palliative care utilization and narrowing this gap among admissions with acute PE.

Obesity and Extracorporeal Membrane Oxygenation (ECMO): Analysis of Outcomes

Traditionally, patients with obesity have been deemed ineligible for extracorporeal life support (ELS) therapies such as extracorporeal membrane oxygenation (ECMO), given the association of obesity with chronic health conditions that contribute to increased morbidity and mortality. Nevertheless, a growing body of literature suggests the feasibility, efficacy, and safety of ECMO in the obese population. This review provides an in-depth analysis of the current literature assessing the effects of obesity on outcomes among patients supported with ECMO (venovenous [VV] ECMO in noncoronavirus disease 2019 and coronavirus disease 2019 acute respiratory distress syndrome, venoarterial [VA] ECMO, and combined VV and VA ECMO), offer a possible explanation of the current findings on the basis of the obesity paradox phenomenon, provides a framework for future studies addressing the use of ELS therapies in the obese patient population, and provides guidance from the literature for many of the challenges related to initiating, maintaining, and weaning ELS therapy in patients with obesity.

Trends and Outcomes of Interhospital Transfer for High-Risk Acute Pulmonary Embolism: A Nationwide Analysis

Background

Data on outcomes of patients with high-risk acute pulmonary embolism (PE) transferred from other hospitals are scarce.

Methods

We queried the Nationwide Readmissions Database for admissions who were ≥18 years old, and with a primary discharge diagnosis of acute high-risk PE between the years 2016 and 2019. The main outcome of interest was the difference in all-cause in-hospital mortality between patients admitted directly to small/medium hospitals; patients admitted directly to large hospitals; and patients transferred to large hospitals.

Results

Among 11,341 weighted hospitalizations with high-risk PE, 631 (5.6%) patients were transferred to large hospitals. There was no significant change in the rates of transfer during the study period. Transferred patients were younger and had a higher prevalence of comorbidities. They were more likely to present with saddle PE and cor pulmonale and were more likely to receive advanced therapies. In-hospital mortality was not different between patients transferred to large hospitals and those admitted directly to large hospitals (adjusted odd ratio [OR] 1.11, 95% confidence interval [CI] 0.81, 1.54) as well as between patients transferred to large hospitals and those admitted directly to small/medium hospitals (aOR 1.28, 95% CI 0.92, 1.76). The rates of major bleeding and cardiac arrest were higher among transferred patients. Admissions for transferred patients were associated with higher cost and longer length of stay.

Conclusion

Transferred patients with high-risk PE were more likely to receive advanced therapies. There was no difference in-hospital mortality rates compared with patients admitted directly to the large or small/medium hospitals.

Gender Disparities in Presentation, Management, and Outcomes of Acute Pulmonary Embolism

Pulmonary embolism (PE) is the third most common cause of cardiovascular death; however, gender disparities in PE remain understudied. All PE cases at a single institution between January 2013 and June 2019 were retrospectively reviewed. The clinical presentation, treatment modalities, and outcomes were compared between men and women using univariate and multivariate analyses adjusting for differences in baseline characteristics. A total of 1,345 patients were diagnosed with acute PE, of whom 56.3% were women (n = 757). Women had a significantly higher mean body mass index (29.4 vs 28.4) and a higher frequency of hypertension (53% vs 46%) and hormone use (6.6% vs 0%; all p <0.02). Men had a higher frequency of smoking (45% vs 33%, p <0.0001). Women had significantly lower PE severity index classifications (p = 0.0009). The rates of intensive care unit admission, vasopressor requirements, extracorporeal membrane oxygenation cannulation, and mechanical ventilation were similar between the genders. There was no significant difference in the treatment modality used between the genders. Although the risk factors and PE severity index class differed between the genders, there was no significant difference in resource utilization or treatment modality. Gender was also not a significant predictor of in-hospital mortality, moderate or severe bleeding, increased length of stay, or readmission in the study population.

Trends in Treatment Patterns and Outcomes of Patients With Pulmonary Embolism in Japan, 2010 to 2020: A Nationwide Inpatient Database Study

Background The impact of major changes in the treatment practice of pulmonary embolism (PE), such as limited indications for systemic thrombolysis and the introduction of direct oral anticoagulants, is not well documented. This study aimed to describe annual trends in the treatment patterns and outcomes in patients with PE. Methods and Results Using the Japanese Diagnosis Procedure Combination inpatient database from April 2010 to March 2021, we identified hospitalized patients with PE. Patients with high-risk PE were defined as those admitted for out-of-hospital cardiac arrest or who received cardiopulmonary resuscitation, extracorporeal membrane oxygenation, vasopressors, or invasive mechanical ventilation on the day of admission. The remaining patients were defined as patients with non-high-risk PE. The patient characteristics and outcomes were reported with fiscal year trend analyses. Of 88 966 eligible patients, 8116 (9.1%) had high-risk PE, and the remaining 80 850 (90.9%) had non-high-risk PE. Between 2010 and 2020, in patients with high-risk PE, the annual proportion of extracorporeal membrane oxygenation use significantly increased from 11.0% to 21.3%, whereas that of thrombolysis use significantly decreased from 22.5% to 15.5% (P for trend <0.001 for both). In-hospital mortality significantly decreased from 51.0% to 43.7% (P for trend=0.04). In patients with non-high-risk PE, the annual proportion of direct oral anticoagulant use increased from 0.0% to 38.3%, whereas that of thrombolysis use significantly decreased from 13.7% to 3.4% (P for trend <0.001 for both). In-hospital mortality significantly decreased from 7.9% to 5.4% (P for trend <0.001). Conclusions Substantial changes in the PE practice and outcomes occurred in patients with high-risk and non-high-risk PE.

Research status and development trend of extracorporeal membrane oxygenation based on bibliometrics

Background

Using bibliometric method to analyze the research status and development trend of extracorporeal membrane oxygenation (ECMO), we aim to provide clinicians, scientists, and stakeholders with the most up-to-date and comprehensive overview of ECMO research.

Materials and methods

Using Excel and VOSviewer, the literature on ECMO was systematically analyzed regarding publication trends, journal source, foundation, countries, institutions, core authors, research hotspots, and market distribution.

Results

There were five important time nodes in the research process of ECMO, including the success of the first ECMO operation, the establishment of ELSO, and the outbreak of influenza A/H1N1 and COVID-19. The R&amp;D centers of ECMO were the United States, Germany, Japan, and Italy, and the attention to ECMO was gradually increasing in China. The products most used in the literature were from Maquet, Medtronic, and LivaNova. Medicine enterprises attached great importance to the funding of ECMO research. In recent years, the literature has mainly focused on the following aspects: the treatment of ARDS, the prevention of coagulation system-related complications, the application in neonatal and pediatric patients, mechanical circulatory support for cardiogenic shock, and ECPR and ECMO during the COVID-19 pandemic.

Conclusion

The frequent epidemic occurrence of viral pneumonia and the technical advancement of ECMO in recent years have caused an increase in clinical applications. The hot spots of ECMO research are shown in the treatment of ARDS, mechanical circulatory support for cardiogenic shock, and the application during the COVID-19 pandemic.

The Challenge of Intermediate-Risk Pulmonary Embolism

BACKGROUND

Intermediate-risk pulmonary embolism is a common disease that is associated with significant morbidity and mortality; however, a standardized treatment protocol is not well-established.

AREAS OF UNCERTAINTY

Treatments available for intermediate-risk pulmonary embolisms include anticoagulation, systemic thrombolytics, catheter-directed therapies, surgical embolectomy, and extracorporeal membrane oxygenation. Despite these options, there is no clear consensus on the optimal indication and timing of these interventions.

THERAPEUTIC ADVANCES

Anticoagulation remains the cornerstone of treatment for pulmonary embolism; however, over the past 2 decades, there have been advances in the safety and efficacy of catheter-directed therapies. For massive pulmonary embolism, systemic thrombolytics and, sometimes, surgical thrombectomy are considered first-line treatments. Patients with intermediate-risk pulmonary embolism are at high risk of clinical deterioration; however, it is unclear whether anticoagulation alone is sufficient. The optimal treatment of intermediate-risk pulmonary embolism in the setting of hemodynamic stability with right heart strain present is not well-defined. Therapies such as catheter-directed thrombolysis and suction thrombectomy are being investigated given their potential to offload right ventricular strain. Several studies have recently evaluated catheter-directed thrombolysis and embolectomies and demonstrated the efficacy and safety of these interventions. Here, we review the literature on the management of intermediate-risk pulmonary embolisms and the evidence behind those interventions.

CONCLUSIONS

There are many treatments available in the management of intermediate-risk pulmonary embolism. Although the current literature does not favor 1 treatment as superior, multiple studies have shown growing data to support catheter-directed therapies as potential options for these patients. Multidisciplinary pulmonary embolism response teams remain a key feature in improving the selection of advanced therapies and optimization of care.

Effectiveness of systemic thrombolysis on clinical outcomes in high-risk pulmonary embolism patients with venoarterial extracorporeal membrane oxygenation: a nationwide inpatient database study

BACKGROUND

Current guidelines recommend systemic thrombolysis as the first-line reperfusion treatment for patients with high-risk pulmonary embolism (PE) who present with cardiogenic shock but do not require venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, little is known about the optimal reperfusion treatment in high-risk PE patients requiring VA-ECMO. We aimed to evaluate whether systemic thrombolysis improved high-risk PE patients' outcomes who received VA-ECMO.

METHODS

This was a retrospective cohort study using the Japanese Diagnosis Procedure Combination inpatient database from July 2010 to March 2021. We identified patients who were diagnosed with PE and received VA-ECMO on the day of admission. Patients who received systemic thrombolysis with monteplase or urokinase within two days of initiating VA-ECMO were defined as the thrombolysis group and the remaining patients as the control group. The primary outcome was in-hospital mortality and secondary outcomes were favorable neurological outcomes, length of hospital stay, VA-ECMO duration, total hospitalization cost, major bleeding, and blood transfusion volume. Propensity-score inverse probability of treatment weighting (IPTW) was performed to compare the outcomes between the groups.

RESULTS

Of 1220 eligible patients, 432 (35%) received systemic thrombolysis within two days of initiating VA-ECMO. Among the unweighted cohort, patients in the thrombolysis group were less likely to have poor consciousness at admission, out-of-hospital cardiac arrest, and left heart catheterization. After IPTW, the patient characteristics were well-balanced between the two groups The crude in-hospital mortality was 52% in the thrombolysis group and 61% in the control group. After IPTW, in-hospital mortality did not differ significantly between the two groups (risk difference: - 3.0%, 95% confidence interval: - 9.6% to 3.5%). There were also no significant differences in the secondary outcomes. Sensitivity analyses showed a significant difference in major bleeding between the monteplase and control groups (risk difference: 6.9%, 95% confidence interval: 1.7% to 12.1%), excluding patients who received urokinase. There were no significant differences in the other sensitivity and subgroup analyses except for the total hospitalization cost.

CONCLUSIONS

Systemic thrombolysis was not associated with reduced in-hospital mortality or increased major bleeding in the high-risk PE patients receiving VA-ECMO. However, systemic thrombolysis with monteplase was associated with increased major bleeding.

Percutaneous Management of High-Risk Pulmonary Embolism

Acute pulmonary embolism (PE) leads to an abrupt increase in pulmonary vascular resistance and right ventricular afterload, and when significant enough, can result in hemodynamic instability. High-risk PE is a dire cardiovascular emergency and portends a poor prognosis. Traditional therapeutic options to rapidly reduce thrombus burden like systemic thrombolysis and surgical pulmonary endarterectomy have limitations, both with regards to appropriate candidates and efficacy, and have limited data demonstrating their benefit in high-risk PE. There are growing percutaneous treatment options for acute PE that include both localized thrombolysis and mechanical embolectomy. Data for such therapies with high-risk PE are currently limited. However, given the limitations, there is an opportunity to improve outcomes, with percutaneous treatments options offering new mechanisms for clot reduction with a possible improved safety profile compared with systemic thrombolysis. Additionally, mechanical circulatory support options allow for complementary treatment for patients with persistent instability, allowing for a bridge to more definitive treatment options. As more data develop, a shift toward a percutaneous approach with mechanical circulatory support may become a preferred option for the management of high-risk PE at tertiary care centers.

Outcomes with use of extra-corporeal membrane oxygenation in high-risk pulmonary embolism: a national database perspective

High-risk pulmonary embolism (PE) patients can be managed with systemic lysis, catheter-based therapies, or surgical embolectomy. Despite the advent of newer therapies, patients with high-risk PE remain with a 50-60% short-term mortality risk. In such patients, extracorporeal membrane oxygenation (ECMO) is increasingly utilized for hemodynamic support. To evaluate the outcomes of the use of ECMO in patients with high-risk PE. Using the National Inpatient Sample (NIS) database, we identified patients with high-risk PE using ICD 10 codes and compared in-hospital outcomes of patients with and without ECMO support. We identified 38,035 patients with high-risk PE, of whom 820 had undergone ECMO placement. Most patients who underwent ECMO were male (54%), white (65%), and with a mean age of 53.7 years. ECMO use was not associated with a meaningful difference in patient mortality when comparing treatment groups (OR, 1.32 ± 0.39; 0.74-2.35; p = 0.35). Rather, ECMO use was associated with a higher frequency of inpatient complications. ECMO use was not associated with a significant difference in patient mortality in patients with high-risk PE.

Sex Differences in Management and Outcomes Among Patients With High-Risk Pulmonary Embolism: A Nationwide Analysis

OBJECTIVE

To examine the sex differences in management and outcomes among patients with high-risk acute pulmonary embolism (PE).

PATIENTS AND METHODS

The Nationwide Readmissions Database was used to identify hospitalizations with high-risk PE from January 1, 2016, to December 31, 2018. Differences in use of advanced therapies, in-hospital mortality, and bleeding events were compared between men and women.

RESULTS

A total of 125,901 weighted hospitalizations with high-risk PE were identified during the study period; 46.3% were women (n=58,253). Women were older and had a higher prevalence of several comorbidities and risk factors of PE such as morbid obesity, diabetes mellitus, chronic pulmonary disease, heart failure, and metastatic cancer. Systemic thrombolysis and catheter-directed interventions were more commonly used among women; however, mechanical circulatory support was less frequently used. In-hospital mortality was higher among women in the unadjusted analysis (30.7% vs 27.8%, P<.001) and after propensity score matching (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.08 to 1.25; P<.001), whereas the rates of intracranial hemorrhage and non-intracranial hemorrhage were not different. On multivariate regression analysis, female sex (OR, 1.18; 95% CI, 1.15 to 1.21; P<.001) was independently associated with increased odds of in-hospital mortality.

CONCLUSION

In this contemporary observational cohort of patients admitted with high-risk PE, women had higher rates of in-hospital mortality despite receiving advanced therapies more frequently, whereas the rate of major bleeding events was not different from men. Efforts are needed to minimize the excess mortality observed among women.

Hospital procedural volume and outcomes with catheter-directed intervention for pulmonary embolism: a nationwide analysis

AIMS

There is limited data on the association between hospital catheter-directed intervention (CDI) volume and outcomes among patients with acute pulmonary embolism (PE).

METHODS AND RESULTS

The Nationwide Readmissions Database years 2016-2019 was utilized to identify hospitalizations undergoing CDI for acute PE. Hospitals were divided into tertiles based on annual CDI volume; low-volume (1-3 procedures), moderate-volume (4-12 procedures) and high-volume (>12 procedures). The primary outcome was all-cause in-hospital mortality. Among 1 436 382 PE admissions, 2.6% underwent CDI; 5.6% were in low-volume, 17.3% in moderate-volume and 77.1% in high-volume hospitals. There was an inverse relationship between hospital CDI volume and in-hospital mortality (coefficient  -0.344, P < 0.001). On multivariable regression analysis, hospitals with high CDI volume were associated with lower in-hospital mortality compared with hospitals with low CDI volume (adjusted odds ratio [OR] 0.71; 95% confidence interval [CI] 0.53, 0.95). Additionally, there was an inverse association between CDI volume and length of stay (LOS) (regression coefficient -0.023, 95% CI -0.027, -0.019) and cost (regression coefficient -74.6, 95% CI -98.8, -50.3). There were no differences in major bleeding and 30-day unplanned readmission rates between the three groups.

CONCLUSION

In this contemporary observational analysis of PE admissions undergoing CDI, there was an inverse association between hospital CDI volume and in-hospital mortality, LOS, and cost. Major bleeding and 30-day unplanned readmission rates were similar between the three groups.

Efficacy and Safety of Veno-Arterial Extracorporeal Membrane Oxygenation in the Treatment of High-Risk Pulmonary Embolism: A Retrospective Cohort Study

Objectives

Veno-arterial extracorporeal membrane oxygenation (ECMO) is increasingly used to treat high-risk pulmonary embolism (PE). However, its efficacy and safety remain uncertain. This retrospective cohort study aimed to determine whether ECMO could improve the clinical outcomes of patients with high-risk PE.

Methods

Forty patients with high-risk PE, who were admitted to Kaohsiung Chang Gung Memorial Hospital between January 2012 and December 2019, were included in this study. Demographic data and clinical outcomes were compared between patients treated without ECMO (non-ECMO group) and those treated with ECMO (ECMO group). Appropriate statistical tools were used to compare variables between groups and the survival was analyzed using the Kaplan-Meier method.

Results

The overall in-hospital mortality rate was 55%, in which 65% (26/40) of patients presented with cardiac arrest with a mortality rate of 77%, which was higher than that of patients without cardiac arrest (14%). There was no significant difference in major complications and in-hospital mortality between the non-ECMO and ECMO groups. However, in subgroup analysis, compared with patients treated without ECMO, earlier ECMO treatment was associated with a reduced risk of cardiac arrest (P = 0.023) and lower in-hospital mortality (P = 0.036). A log-rank test showed a significantly higher cumulative overall survival in the earlier ECMO treatment group (P = 0.033).

Conclusions

In this retrospective cohort study, earlier ECMO treatment was associated with lower in-hospital mortality among unstable patients without cardiac arrest. Our findings suggest that ECMO can be considered as an initial treatment option for patients with high-risk PE in higher-volume hospitals.

Survival of Children With Pulmonary Embolism Supported by Extracorporeal Membrane Oxygenation

The purpose of this study was to describe the demographics and in-hospital mortality of children (<18 years) from 2007 to 2018 supported by Extracorporeal Membrane Oxygenation (ECMO) for a primary diagnosis of pulmonary embolism and reported to the Extracorporeal Life Support Organization database. Fifty-six patients were identified and 54 were included in this analysis. A total of 33 patients (61%) survived. No differences in demographics or ECMO details (duration, mode, and support type) were found between survivors and non-survivors. When ECMO complications were compared, pulmonary bleeding occurred more frequently in non-survivors (23.8%, n = 5) compared to survivors (n = 0) (p = 0.006).

Current interventional therapies in acute pulmonary embolism

Pulmonary embolism (PE) is the third leading cause of cardiovascular mortality. The management of PE is currently evolving given the development of new technologies and team-based approaches. This document will focus on risk stratification of PEs, review of the current interventional therapies, the role of clinical endpoints to assess the effectiveness of different interventional therapies, and the role for mechanical circulatory support in the complex management of this disease.

Clinical use and outcome of extracorporeal membrane oxygenation in patients with pulmonary embolism

AIM OF THE STUDY

Extracorporeal membrane oxygenation (ECMO) is considered a life-saving treatment option for patients in cardiogenic shock or cardiac arrest undergoing cardiopulmonary resuscitation (CPR) due to acute pulmonary embolism (PE). We sought to analyze use and outcome of ECMO with or without adjunctive treatment strategies in patients with acute PE.

METHODS

We retrospectively analyzed data on patient characteristics, treatments, and in-hospital outcomes for all PE patients (ICD-code I26) undergoing ECMO in Germany between 2005 and 2018.

RESULTS

At total of 1,172,354 patients were hospitalized with PE; of those, 2,197 (0.2%) were treated with ECMO support. Cardiac arrest requiring cardiopulmonary resuscitation was present in 77,196 (6.5%) patients. While more than one fourth of those patients were treated with systemic thrombolysis alone (n = 20,839 patients; 27.0%), a minority of patients received thrombolysis and VA-ECMO (n = 165; 0.2%), embolectomy and VA-ECMO (n = 385; 0.5%) or VA-ECMOalone (n = 588; 0.8%). A multivariable logistic regression analysis indicated the lowest risk for in-hospital death in patients who received embolectomy in combination with VA-ECMO (OR, 0.50 [95% CI, 0.41-0.61], p < 0.001), thrombolysis and VA-ECMO (0.60 [0.43-0.85], p = 0.003) or VA-ECMO alone (0.68 [0.57-0.82], p < 0.001) compared to thrombolysis alone (1.04 [0.99-1.01], p = 0.116).

CONCLUSION

Our findings suggest that the use of VA-ECMO alone or as part of a multi-pronged reperfusion approach including embolectomy or thrombolysis might offer survival advantages compared to thrombolysis alone in patients with PE deteriorating to cardiac arrest.

Acute Pulmonary Embolism During Pregnancy and Puerperium: National Trends and In-Hospital Outcomes

OBJECTIVE

To investigate the trend and outcomes of acute pulmonary embolism (PE) during pregnancy and puerperium using a large national database.

PATIENTS AND METHODS

The National Inpatient Sample was queried to identify pregnancy-related hospitalizations in the United States from January 1, 2007, through September 30, 2015. Temporal trends in the rates of acute PE and in-hospital mortality rates were extracted.

RESULTS

Among 37,524,314 hospitalizations, 6,333 patients (0.02%) had acute PE. The prevalence of comorbidities and risk factors such as hypertension, obesity, and smoking increased, but rates of acute PE did not change significantly (18.01 in 2007 vs 19.36 in 2015, per 100,000 hospitalizations, Ptrends=.21). Advanced therapies were used in a small number of women (systemic thrombolysis: 2.4%, surgical pulmonary embolectomy: 0.5%, and inferior vena cava filter in 8.3%). Rates of in-hospital mortality were almost 200-fold higher among those who had acute PE (29.3 vs 0.13, per 1000 pregnancy-related, P<.001). The rate of in-hospital mortality did not change among women with acute PE (2.6% in 2007 vs 2.5% in 2015, Ptrends=.74).

CONCLUSION

In this contemporary analysis of pregnancy-related hospitalizations, acute PE was uncommon, but rates have not decreased over the past decade. Acute PE during pregnancy and puerperium was associated with high maternal mortality, and the rates of in-hospital mortality have not improved. Future studies to improve prevention and management of acute PE during pregnancy and puerperium are warranted.

Venoarterial Extracorporeal Membrane Oxygenation for Acute Massive Pulmonary Embolism: a Meta-Analysis and Call to Action

Venoarterial extracorporeal membrane oxygenation (ECMO) has been used to treat acute massive pulmonary embolism (PE) patients. However, the incremental benefit of ECMO to standard therapy remains unclear. Our meta-analysis objective is to compare in-hospital mortality in patients treated for acute massive PE with and without ECMO. The National Library of Medicine MEDLINE (USA), Web of Science, and PubMed databases from inception through October 2020 were searched. Screening identified 1002 published articles. Eleven eligible studies were identified, and 791 patients with acute massive PE were included, of whom 270 received ECMO and 521 did not. In-hospital mortality was not significantly different between patients treated with vs. without ECMO (OR = 1.24 [95% CI, 0.63–2.44], p = 0.54). However, these findings were limited by significant study heterogeneity. Additional research will be needed to clarify the role of ECMO in massive PE treatment.

Survival of patients with acute pulmonary embolism treated with venoarterial extracorporeal membrane oxygenation: A systematic review and meta-analysis

BACKGROUND

To examine whether venoarterial extracorporeal membrane oxygenation (VA-ECMO) improves survival of patients with acute pulmonary embolism (PE).

METHODS

Following the PRISMA guidelines, a systematic search was conducted up to August 2019 of the databases: PubMed/MEDLINE, EMBASE and Cochrane. All studies reporting the survival of adult patients with acute PE treated with VA-ECMO and including four patients or more were included. Exclusion criteria were: correspondences, reviews and studies in absence of a full text, written in other languages than English or Dutch, or dating before 1980. Short-term (hospital or 30-day) survival data were pooled and presented with relative risks (RR) and 95% confidence intervals (95% CI). Also, the following pre-defined factors were evaluated for their association with survival in VA-ECMO treated patients: age > 60 years, male sex, pre-ECMO cardiac arrest, surgical embolectomy, catheter directed therapy, systemic thrombolysis, and VA-ECMO as single therapy.

RESULTS

A total of 29 observational studies were included (N = 1947 patients: VA-ECMO N = 1138 and control N = 809). There was no difference in short-term survival between VA-ECMO treated patients and control patients (RR 0.91, 95% CI 0.71-1.16). In acute PE patients undergoing VA-ECMO, age > 60 years was associated with lower survival (RR 0.72, 95% CI 0.52-0.99), surgical embolectomy was associated with higher survival (RR 1.96, 95% CI 1.39-2.76) and pre-ECMO cardiac arrest showed a trend toward lower survival (RR 0.88, 95% CI 0.77-1.01). The other evaluated factors were not associated with a difference in survival.

CONCLUSIONS

At present, there is insufficient evidence that VA-ECMO treatment improves short-term survival of acute PE patients. Low quality evidence suggest that VA-ECMO patients aged ≤60 years or who received SE have higher survival rates. Considering the limited evidence derived from the present data, this study emphasizes the need for prospective studies.

PROTOCOL REGISTRATION

PROSPERO CRD42019120370.

Advanced Management of Intermediate- and High-Risk Pulmonary Embolism: JACC Focus Seminar

Intermediate-risk (submassive) pulmonary embolism (PE) describes normotensive patients with evidence of right ventricular compromise, whereas high-risk (massive) PE comprises those who have experienced hemodynamic decompensation with hypotension, cardiogenic shock, or cardiac arrest. Together, these 2 syndromes represent the most clinically challenging manifestations of the PE spectrum. Prompt therapeutic anticoagulation remains the cornerstone of therapy for both intermediate- and high-risk PE. Patients with intermediate-risk PE who subsequently deteriorate despite anticoagulation and those with high-risk PE require additional advanced therapies, typically focused on pulmonary artery reperfusion. Strategies for reperfusion therapy include systemic fibrinolysis, surgical pulmonary embolectomy, and a growing number of options for catheter-based therapy. Multidisciplinary PE response teams can aid in selection of appropriate management strategies, especially where gaps in evidence exist and guideline recommendations are sparse.

Crucial considerations: Sex differences in the epidemiology, diagnosis, treatment, and outcomes of acute pulmonary embolism in non-pregnant adult patients

Acute pulmonary embolism (PE) affects over 600,000 Americans per year and is a common diagnostic consideration among emergency department patients. Although there are well-documented differences in the diagnosis, treatment, and outcomes of cardiovascular conditions, such as ischemic heart disease and stroke, the influence of sex and gender on PE remains poorly understood. The overall age-adjusted incidence of PE is similar in women and men, but women have higher relative rates of PE during early and mid-adulthood (ages 20-40 years); whereas, men have higher rates of PE after age 60 years. Women are tested for PE at far higher rates than men, yet women who undergo computed tomography pulmonary angiography are ultimately diagnosed with PE 35%-55% less often than men. Among those diagnosed with PE, women are more likely to have severe clinical features, such as hypotension and signs of right ventricular dysfunction. When controlled for PE severity, women are less likely to receive reperfusion therapies, such as thrombolysis. Finally, women have more bleeding complications for all types of anticoagulation. Further investigation of possible sex-specific diagnostic and treatment algorithms is necessary in order to more accurately detect and treat acute PE in non-pregnant adults.

Use of extracorporeal membrane oxygenation in high-risk acute pulmonary embolism: A systematic review and meta-analysis

Extracorporeal membrane oxygenation (ECMO) represents a therapeutic option for cardiopulmonary support in patients with high-risk pulmonary embolism (PE); however, no definite consensus exists on ECMO use in high-risk PE. Hence, we aim to provide insights into its real-world use pooling together all available published experiences. We performed a systematic review and pooled analysis of all published studies (up to April 17, 2020) investigating ECMO support in high-risk PE. All studies including at least four patients were collectively analyzed. Study outcomes were early all-cause death (primary endpoint) and relevant in-hospital adverse events. A total of 21 studies were included in the pooled analysis (n = 635 patients). In this population (mean age 47.8 ± 17.3 years, 44.5% females), ECMO was indicated for cardiac arrest in 62.3% and immediate ECMO support was pursued in 61.9% of patients. Adjunctive reperfusion therapies were implemented in 57.0% of patients. Pooled estimate rate of early all-cause mortality was 41.1% (95% CI 27.7%-54.5%). The most common in-hospital adverse event was major bleeding, with an estimated rate of 28.6% (95%CI 21.0%-36.3%). At meta-regression analyses, no significant impact of multiple covariates on the primary endpoint was found. In this systematic review of patients who received ECMO for high-risk PE, pooled all-cause mortality was 41.1%. Principal indication for ECMO was cardiac arrest, cannulation was chiefly performed at presentation, and major bleeding was the most common complication.

Extracorporeal Membrane Oxygenation Utility in Postpartum Patients

Although extracorporeal membrane oxygenation (ECMO) has been used in many different populations, its use in pregnant or postpartum patients has not been widely studied. This article reviews the ECMO experience in this population at a large urban hospital. Electronic medical records for all pregnant or postpartum patients who required ECMO between 2012 and 2019 were retrospectively reviewed. Data on clinical characteristics, outcomes, and complications were gathered. Comparisons between survivors and nonsurvivors were completed. Ten postpartum patients were identified. The patients presented as follows: four with cardiac arrest, one with a massive pulmonary embolism, three with acute respiratory distress syndrome (ARDS), one with combined ARDS and cardiogenic shock, and one with suspected amniotic embolism. Survival to decannulation was 70%, and survival to discharge was 60%. When comparing survivors vs. nonsurvivors, ECMO survivors tended to have shorter support times vs. nonsurvivors. Otherwise, no differences were noted in age, mechanical ventilation time, or length of stay. Disseminated intravascular coagulation was a common phenomenon in this patient cohort. After initiation of ECMO, elevated serum lactate levels, lower systolic blood pressure, and acute renal failure were predictors of mortality. In a single institution at a large metroplex, we present data regarding the use of ECMO in postpartum patients. ECMO can be successfully used in selected postpartum patients with severe cardiac or respiratory dysfunction. Multidisciplinary collaboration on a regular basis will streamline the ECMO referral in a timely manner. Furthermore, larger studies are indicated to understand the utility of ECMO in larger cohorts.

Massive pulmonary embolism with intra-hospital cardiac arrest and full recovery of right ventricular function after veno-arterial extracorporeal membrane oxygenation therapy: a case report

Background

Massive pulmonary embolism (PE) with shock constitutes a life-threatening disease, challenging physicians with the need for fast decision-making in an emergency situation. While thrombolytic treatment or thrombectomy are considered the treatment of choice in high-risk PE, these strategies might not be able to unload the right ventricle (RV) fast enough in some patients with severe cardiogenic shock.

Case summary

We present a case of a patient with massive bilateral central PE who presented in cardiogenic shock, rapidly deteriorating to cardiac arrest. After successful re-establishing spontaneous circulation, the patient remained highly unstable, necessitating a treatment strategy ensuring a quick stabilization of the circulation. Therefore, we decided to use veno-arterial extracorporeal membrane oxygenation (vaECMO) as a supportive strategy allowing for autolysis of the lung to dissolve the thrombi (bridge to recovery). We were able to wean the patient from vaECMO support within 4 days and documented a complete recovery of right ventricular in echocardiography before hospital discharge.

Discussion

The concept of vaECMO treatment alone might be a valuable alternative in selected patients with massive PE and cardiogenic shock, in whom thrombolytic therapy might not unload the RV fast enough.

Efficacy and safety of extracorporeal membrane oxygenation for high-risk pulmonary embolism: A systematic review and meta-analysis

High-risk pulmonary embolism (PE) requires hemodynamic and respiratory support along with reperfusion strategies. Recently updated European guidelines assign a low class of recommendation to extracorporeal membrane oxygenation (ECMO) for high-risk PE. This systematic review assessed clinical outcomes after ECMO in high-risk PE. We searched electronic databases including PubMed, Embase and Web of Science from January 2000 to April 2020. Efficacy outcomes included in-hospital survival with good neurological outcome and survival at follow-up. Safety outcomes included lower limb ischemia and hemorrhagic and ischemic stroke. Where possible (absence of high heterogeneity), meta-analyses of outcomes were undertaken using a random-effects model. We included 16 uncontrolled case-series (533 participants). In-hospital survival with good neurological outcome ranged between 50% and 95% while overall survival at follow-up ranged from 35% to 95%, both with a major degree of heterogeneity (I² > 70%). The prevalence of lower limb ischemia was 8% (95% CI 3% to 15%). The prevalence of stroke (either hemorrhagic or ischemic) was 11% (95% CI 3% to 23%), with notable heterogeneity (I² = 63.35%). Based on currently available literature, it is not possible to draw definite conclusions on the usefulness of ECMO for high-risk PE. Prospective, multicenter, large-scale studies or nationwide registries are needed to best define the role of ECMO for high-risk PE. PROSPERO registration ID: CRD42019136282.

Simultaneous Thrombolysis and Extracorporeal Membrane Oxygenation for Acute Massive Pulmonary Emboli

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used in patients with circulatory collapse or extremely unstable hemodynamics caused by acute massive pulmonary embolism (PE). The effectiveness of simultaneous thrombolytic therapy has been rarely investigated in these patients after being stabilized with ECMO.

METHODS

From January 2008 to December 2018 consecutive patients with acute massive PE requiring ECMO supported in a tertiary medical center were included for retrospective analysis.

RESULTS

Thirteen patients with PE underwent ECMO implantation and received subsequent thrombolytic therapy as a definite treatment for PE. All patients survived their ECMO courses to a successful decannulation, with a mean ECMO support duration of 6.23 ± 4.69 days. Eleven patients (84.62%) survived to hospital discharge. All survivors were alive during follow-up, although 2 patients (18.2%) had permanent dysfunctional neurologic complications. Major bleeding complications occurred in 4 patients (30.77%), whereas no patient had intracranial hemorrhage. Systemic thrombolysis showed comparable outcomes of catheter-directed thrombolysis in our patients who underwent ECMO.

CONCLUSIONS

Thrombolysis-based therapeutic strategy under ECMO could be a relatively safe and effective definitive treatment for patients with acute massive PE, even for those who were resuscitated. Bleeding complications remain a major concern and should be monitored and managed immediately.

Clinical and imaging outcomes after intermediate- or high-risk pulmonary embolus

Long-term outcomes after acute pulmonary embolism vary from complete resolution to chronic thromboembolic pulmonary hypertension (CTEPH). Guidelines after acute pulmonary embolism are generally limited to anticoagulation duration. We assessed patients with estimated prognosis >1 year in our pulmonary hypertension clinic 2-4 months after treatment for intermediate- or high-risk acute pulmonary embolism. At follow-up, ventilation-perfusion scan and echocardiogram were offered. The aim of this study was to assess for recurrent symptomatic disease, residual imaging defects or right ventricular dysfunction, and functional disability after acute management of pulmonary embolism. After treatment for acute intermediate- or high-risk pulmonary embolism, 104 patients followed up in pulmonary hypertension clinic. Of those, 55% of patients had self-reported limitation in activity. No patients had symptomatic recurrence of pulmonary embolism. Forty-eight percent of patients had residual perfusion defects on perfusion imaging, while 91% of patients had either normal or only mildly enlarged right ventricles. We identified heart failure preserved ejection fraction, iron deficiency, and obstructive sleep apnea as significant contributors to breathlessness. Treatment of these conditions was associated with improvement. Surprisingly, we diagnosed CTEPH in nine patients; for some, chronic thrombus may already have been present at the time of index evaluation. Our findings suggest that follow-up in a dedicated pulmonary hypertension clinic 2-4 months after acute intermediate- or high-risk pulmonary embolism may add value to patient care. We identified treatable comorbidities that could be contributing to post-pulmonary embolism syndrome as well as CTEPH.

Use of extracorporeal membrane oxygenation in obstetric patients: a retrospective cohort study

PURPOSE

There is little information on the use of extracorporeal membrane oxygenation (ECMO) in pregnant women. Our objectives are to estimate the use of ECMO in pregnant patients, identify clinical conditions associated with ECMO use, and assess survival rates by the associated condition.

METHODS

Using the Healthcare Cost and Utilization Project-Nationwide Inpatient Sample, we carried out a retrospective cohort study of all delivery admissions in the United States from January 1, 1999, to October 1, 2015. Within the cohort, women who received ECMO therapy were identified using ICD-9 codes and then survival rates among these women were calculated.

RESULTS

There were 83 women who underwent ECMO therapy in our cohort of 15,335,205 births, for an overall ECMO use rate of 0.54/100,000 pregnancies. The incidence of ECMO use increased from 0.23/100,000 in 1999 to 2.57/100,000 in 2015. Patients on ECMO were more likely to be older, have a lower income, and have pre-existing medical conditions when compared with the patients not on ECMO. The overall survival rate for the ECMO group was 62.7%. The most common reason for ECMO use was acute respiratory failure. Etiologies associated with the highest survival in those on ECMO were pneumonia and venous thromboembolism, which were found to have survival rates of 75.0% and 81.0%, respectively.

CONCLUSION

The incidence of ECMO use in the obstetric population increased over the last decade and a half. Although it carries a limited survival rate within this population, it has proven life-saving for many suffering from complications of pregnancy and delivery.

Massive pulmonary embolism: embolectomy or extracorporeal membrane oxygenation?

PURPOSE OF REVIEW

To highlight updates on the use of extracorporeal membrane oxygenation (ECMO) and surgical embolectomy in the treatment of massive pulmonary embolism.

RECENT FINDINGS

Outcomes for surgical embolectomy for massive pulmonary embolism have improved in the recent past. More contemporary therapeutic options include catheter embolectomy, which although offer less invasive means of treating this condition, need further study. The use of ECMO as either a bridge or mainstay of treatment in patients with contraindications to fibrinolysis and surgical embolectomy, or have failed initial fibrinolysis, has increased, with data suggesting improved outcomes with earlier implementation in selected patients.

SUMMARY

Although surgical embolectomy continues to be the initial treatment of choice in massive pulmonary embolism with contraindications or failed fibrinolysis, the use of ECMO in these high-risk patients provides an important tool in managing this often fatal condition.

Future perspectives in catheter-based treatment of pulmonary embolism

Pulmonary embolism is the third commonest cause of cardiovascular death globally. The majority of such patients present with low-risk features and can be managed with simple anticoagulation; however, a large group of patients exhibit evidence of right ventricular dysfunction on echocardiography or CT at the time of presentation and these patients are at risk of early haemodynamic compromise, particularly in those with abnormal cardiac biomarkers. Catheter-directed thrombolysis has been proposed as a treatment-strategy for patients with pulmonary embolism with evidence of acute right ventricular dysfunction. We review the current technologies in mainstream use, the evidence base in support of their use and discuss future research requirements in this area.

Future perspectives in catheter-based treatment of pulmonary embolism

Pulmonary embolism is the third commonest cause of cardiovascular death globally. The majority of such patients present with low-risk features and can be managed with simple anticoagulation; however, a large group of patients exhibit evidence of right ventricular dysfunction on echocardiography or CT at the time of presentation and these patients are at risk of early haemodynamic compromise, particularly in those with abnormal cardiac biomarkers. Catheter-directed thrombolysis has been proposed as a treatment-strategy for patients with pulmonary embolism with evidence of acute right ventricular dysfunction. We review the current technologies in mainstream use, the evidence base in support of their use and discuss future research requirements in this area.