Clinical course and outcome of patients with acute pulmonary embolism rescued by veno-arterial extracorporeal membrane oxygenation: a retrospective review of 21 cases

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.

Neurological outcomes and reperfusion strategies in out-of-hospital cardiac arrest patients due to pulmonary embolism who underwent venoarterial extracorporeal membrane oxygenation: A post-hoc analysis of a multicenter retrospective cohort study

INTRODUCTION

This study aimed to evaluate the effect of different reperfusion strategies on neurological outcomes in patients with pulmonary embolism who received venoarterial extracorporeal membrane oxygenation (VA-ECMO) for out-of-hospital cardiac arrest (OHCA).

METHODS

This was a post-hoc analysis of a multicenter retrospective cohort study conducted in 36 institutions in Japan over six years. We included patients who underwent VA-ECMO and were diagnosed with pulmonary embolism caused by OHCA. Neurological outcomes were evaluated on the basis of the cerebral performance category at hospital discharge. We also assessed the association between reperfusion strategies and successful separation from ECMO.

RESULTS

Among the 78 included patients, approximately half were successfully weaned from ECMO. Hospital mortality and favorable neurological outcomes at hospital discharge were 60.3% and 17.9%, respectively. Thirty-one patients (39.7%) underwent reperfusion strategies after ECMO, including 13 who received systemic thrombolytic therapy and 18 who underwent mechanical reperfusion strategy. After adjusting for prespecified covariates using the competing risk model, reperfusion strategies increased ECMO separation rate (systemic thrombolytic therapy: subdistribution hazard ratio [sHR] 2.24, 95% confidence interval [CI] 1.21-4.17, P = 0.011; mechanical reperfusion strategy: sHR 1.70, 95% CI 0.86-3.41, P = 0.129) compared with anticoagulation therapy alone, whereas higher cardiac Sequential Organ Failure Assessment score decreased ECMO separation rate (sHR 0.81, 95% CI 0.67-0.97, P = 0.020).

CONCLUSIONS

Favorable neurological outcomes were observed in less than 20% of patients with OHCA due to pulmonary embolism undergoing ECMO. Reperfusion strategies may be associated with shorter ECMO durations in these patients.

CLINICAL TRIAL REGISTRATION

https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000041577 (unique identifier: UMIN000036490).

Venoarterial Extracorporeal Membrane Oxygenation in High-Risk Pulmonary Embolism: A Case Series and Literature Review

Background

High-risk Pulmonary Embolism (PE) has an ominous prognosis and requires emergent reperfusion therapy, primarily systemic thrombolysis (ST). In deteriorating patients or with contraindications to ST, Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) may be life-saving, as supported by several retrospective studies. However, due to the heterogeneous clinical presentation (refractory shock, resuscitated cardiac arrest (CA) or refractory CA), the real impact of VA-ECMO in high-risk PE remains to be fully determined. In this study, we present our centre experience with VA-ECMO for high-risk PE.

Method

From 2008 to 2020, we analyzed all consecutive patients treated with VA-ECMO for high-risk PE in our tertiary 35-bed intensive care unit (ICU). Demographic variables, types of reperfusion therapies, indications for VA-ECMO (refractory shock or refractory CA requiring extra-corporeal cardiopulmonary resuscitation, ECPR), hemodynamic variables, initial arterial blood lactate and ICU complications were recorded. The primary outcome was ICU survival, and secondary outcome was hospital survival.

Results

Our cohort included 18 patients (9F/9M, median age 57 years old). VA-ECMO was indicated for refractory shock in 7 patients (2 primary and 5 following resuscitated CA) and for refractory CA in 11 patients. Eight patients received anticoagulation only, 9 received ST, and 4 underwent surgical embolectomy. ICU survival was 1/11 (9%) for ECPR vs 3/7 (42%) in patients with refractory shock (p = 0.03, log-rank test). Hospital survival was 0/11 (0%) for ECPR vs 3/7 for refractory shock (p = 0.01, log-rank test). Survivors and Non-survivors had comparable demographic and hemodynamic variables, pulmonary obstruction index, and amounts of administered vasoactive drugs. Pre-ECMO lactate was significantly higher in non-survivors. Massive bleeding was the most frequent complication in survivors and non-survivors, and was the direct cause of death in 3 patients, all treated with ST.

Conclusions

VA-ECMO for high-risk PE has very different outcomes depending on the clinical context. Furthermore, VA-ECMO was associated with significant bleeding complications, with more severe consequences following systemic thrombolysis. Future studies on VA-ECMO for high-risk PE should therefore take into account the distinct clinical presentations and should determine the best strategy for reperfusion in such circumstances.

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.

Long-term follow-up and quality of life in patients receiving extracorporeal membrane oxygenation for pulmonary embolism and cardiogenic shock

Background

Since 2019, European guidelines recommend considering extracorporeal life support as salvage strategy for the treatment of acute high-risk pulmonary embolism (PE) with circulatory collapse or cardiac arrest. However, data on long-term survival, quality of life (QoL) and cardiopulmonary function after extracorporeal membrane oxygenation (ECMO) are lacking.

Methods

One hundred and nineteen patients with acute PE and severe cardiogenic shock or in need of mechanical resuscitation (CPR) received venoarterial or venovenous ECMO from 2007 to 2020. Long-term data were obtained from survivors by phone contact and personal interviews. Follow-up included a QoL analysis using the EQ-5D-5L questionnaire, echocardiography, pulmonary function testing and cardiopulmonary exercise testing.

Results

The majority of patients (n = 80, 67%) were placed on ECMO during or after CPR with returned spontaneous circulation. Overall survival to hospital discharge was 45.4% (54/119). Nine patients died during follow-up. At a median follow-up of 54.5 months (25–73; 56 ± 38 months), 34 patients answered the QoL questionnaire. QoL differed largely and was slightly reduced compared to a German reference population (EQ5D5L index 0.7 ± 0.3 vs. 0.9 ± 0.04; p  < 0.01). 25 patients (73.5%) had no mobility limitations, 22 patients (65%) could handle their activities, while anxiety and depression were expressed by 10 patients (29.4%). Return-to-work status was 33.3% (average working hours: 36.2 ± 12.5 h/per week), 15 (45.4%) had retired from work early. 12 patients (35.3%) expressed limited exercise tolerance and dyspnea. 59% (20/34) received echocardiography and pulmonary function testing, 50% (17/34) cardiopulmonary exercise testing. No relevant impairment of right ventricular function and an only slightly reduced mean peak oxygen uptake (76.3% predicted) were noted.

Conclusions

Survivors from severe intractable PE in cardiogenic shock or even under CPR with ECMO seem to recover well with acceptable QoL and only minor cardiopulmonary limitations in the long term. To underline these results, further research with larger study cohorts must be obtained.