Extracorporeal Membrane Oxygenation—First Strategy for Acute Life-Threatening Pulmonary Embolism

Catheter-based techniques for pulmonary embolism treatment

Pulmonary embolism (PE) is a life-threatening condition characterised by occlusion of the pulmonary vasculature, with a global incidence of approximately 1 in 1,000 patients. While pharmacological therapy remains the cornerstone of PE management, selected patients may benefit from catheter-directed treatments due to their potential for rapid symptom relief and swift haemodynamic stabilisation. Catheter-directed thrombolysis and catheter-directed mechanical thrombectomy are current treatment options, though their availability is still limited. This review provides a practical outlook on catheter-directed therapies for PE, outlining optimal procedural planning, device selection, technical execution, evaluation of results, and management of complications.

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.

The Role of IVC Filters in the Management of Acute Pulmonary Embolism

Venous thromboembolism (VTE), comprising deep venous thrombosis (DVT) and pulmonary embolism (PE), is a prevalent cardiovascular condition, ranking third globally after myocardial infarction and stroke. The risk of VTE rises with age, posing a growing concern in aging populations. Acute PE, with its high morbidity and mortality, emphasizes the need for early diagnosis and intervention. This review explores prognostic factors for acute PE, categorizing it into low-risk, intermediate-risk, and high-risk based on hemodynamic stability and right ventricular strain. Timely classification is crucial for triage and treatment decisions. In the contemporary landscape, low-risk PE patients are often treated with Direct Oral Anticoagulants (DOACS) and rapidly discharged for outpatient follow-up. Intermediate- and high-risk patients may require advanced therapies, such as systemic thrombolysis, catheter-directed thrombolysis, mechanical thrombectomy, and IVC filter placement. The latter, particularly IVC filters, has witnessed increased usage, with evolving types like retrievable and convertible filters. However, concerns arise regarding complications and the need for timely retrieval. This review delves into the role of IVC filters in acute PE management, addressing their indications, types, complications, and retrieval considerations. The ongoing debate surrounding IVC filter use, especially in patients with less conventional indications, reflects the need for further research and data. Despite complications, recent studies suggest that clinically significant issues are rare, sparking discussions on the appropriate and safe utilization of IVC filters in select PE cases. The review concludes by highlighting current trends, gaps in knowledge, and potential avenues for advancing the role of IVC filters in future acute PE management.

Extracorporeal Membrane Oxygenation for Pulmonary Embolism: A Systematic Review and Meta-Analysis

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) for high-risk pulmonary embolism (HRPE) with haemodynamic instability or profound cardiogenic shock has been reported. Guidelines currently support the use of ECMO only in patients with cardiac arrest or circulatory collapse and in conjunction with other curative therapies. We aimed to characterise the mortality of adults with HRPE treated with ECMO, identify factors associated with mortality, and compare different adjunct curative therapies.

METHODS

We conducted a systematic review and meta-analysis, searching four international databases from their inception until 25 June 2023 for studies reporting on more than five patients receiving ECMO for HRPE. Random-effects meta-analyses were conducted. The primary outcome was in-hospital mortality. A subgroup analysis investigating the outcomes with curative treatment for HRPE was also performed. The intra-study risk of bias and the certainty of evidence were also assessed. This study was registered with PROSPERO (CRD42022297518).

RESULTS

A total of 39 observational studies involving 6409 patients receiving ECMO for HRPE were included in the meta-analysis. The pooled mortality was 42.8% (95% confidence interval [CI]: 37.2% to 48.7%, moderate certainty). Patients treated with ECMO and catheter-directed therapy (28.6%) had significantly lower mortality (p < 0.0001) compared to those treated with ECMO and systemic thrombolysis (57.0%). Cardiac arrest prior to ECMO initiation (regression coefficient [B]: 1.77, 95%-CI: 0.29 to 3.25, p = 0.018) and pre-ECMO heart rate (B: -0.076, 95%-CI: -0.12 to 0.035, p = 0.0003) were significantly associated with mortality. The pooled risk ratio when comparing mortality between patients on ECMO and those not on ECMO was 1.51 (95%-CI: 1.07 to 2.14, p < 0.01) in favour of ECMO. The pooled mortality was 55.2% (95%-CI: 47.7% to 62.6%), using trim-and-fill analysis to account for the significant publication bias.

CONCLUSIONS

More than 50% of patients receiving ECMO for HRPE survive. While outcomes may vary based on the curative therapy used, early ECMO should be considered as a stabilising measure when treating patients with HRPE. Patients treated concurrently with systemic thrombolysis have higher mortality than those receiving ECMO alone or with other curative therapies, particularly catheter-directed therapies. Further studies are required to explore ECMO vs. non-ECMO therapies in view of currently heterogenous datasets.

Extracorporeal membrane oxygenation for acute pulmonary embolism after postoperative craniocerebral trauma: a case report

Introduction

Massive pulmonary embolism (PE) is a life-threatening complication of major surgery with a mortality rate of up to 50%. Extracorporeal membrane oxygenation (ECMO) is primarily used for respiratory and circulatory support. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is used to stabilize patients with acute massive PE. Acute brain injury, vascular disease, and immunosuppression are contraindications to ECMO, as stated in the 2021 Extracorporeal Life Support Organization guidelines.

Case summary

We report a case of a patient with craniocerebral trauma whose postoperative course was complicated by massive PE and subsequent cardiac arrest that required urgent VA-ECMO, followed by anticoagulation with heparin. The patient showed hemodynamic improvement and was discharged 68 days after hospitalization.

Discussion

ECMO has gradually been accepted for patients with craniocerebral injuries. The safety and effectiveness of ECMO in patients with craniocerebral injury, along with the optimal duration of ECMO and anticoagulation strategies, require further study.