What's new in severe pulmonary embolism?

Extracorporeal membrane oxygenation for the treatment of massive pulmonary embolism. An analysis of the ELSO database

AIM

Extracorporeal membrane oxygenation (ECMO) may be beneficial in treatment of massive pulmonary embolus (PE), however the current evidence to guide its use is limited. We aimed to compare the incidence, characteristics, treatments, and outcomes of patients with massive PE by mode of ECMO from a large international registry.

METHODS

Retrospective observational study of the Extracorporeal Life Support Organization (ELSO) database.

RESULTS

A total of 821 patients underwent 833 ECMO episodes for PE. Mean age was 49 (±15) years, 408 (50.1%) were female, and 450 (54.7%) had a cardiac arrest prior to ECMO initiation. Venoarterial (VA) ECMO was the most common mode in 489 (58.7%), followed by extracorporeal cardiopulmonary resuscitation (ECPR) in 229 (27.4%) and venovenous (VV) ECMO in 85 (10.2%). The number of episodes per year increased over the study period, predominantly driven by an increase in ECPR. In-hospital mortality was the highest for ECPR 156/229 (68.1%), followed by VA ECMO 209/498 (42.7%) and VV ECMO 24/85 (28.2%) P < 0.001. After controlling for univariate and clinically significant variables at the time of ECMO initiation, increasing age (OR 1.02 (1.00-1.03), lower pH (OR 0.18 (0.03-0.44), lower diastolic blood pressure (OR 0.99 (0.97-1.00) and ECPR mode (OR 3.67 (1.46-9.230) were independently associated with in-hospital mortality.

CONCLUSION

ECMO use for massive PE is increasing globally, and overall mortality rates compare favorably with other indications of ECMO. The use of ECPR and worsening metabolic status at initiation were associated with higher in-hospital mortality, suggesting delays in initiating ECMO should be avoided.

Cardiac arrest secondary to pulmonary embolism treated with extracorporeal cardiopulmonary resuscitation: Six case reports

BACKGROUND

Massive pulmonary embolism (PE) results in extremely high mortality rates. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide circulatory and oxygenation support and rescue patients with massive PE. However, there are relatively few studies of extracorporeal cardiopulmonary resuscitation (ECPR) in patients with cardiac arrest (CA) secondary to PE. The aim of the present study is to investigate the clinical use of ECPR in conjunction with heparin anticoagulation in patients with CA secondary to PE.

CASE SUMMARY

We report the cases of six patients with CA secondary to PE treated with ECPR in the intensive care unit of our hospital between June 2020 and June 2022. All six patients experienced witnessed CA whilst in hospital. They had acute onset of severe respiratory distress, hypoxia, and shock rapidly followed by CA and were immediately given cardiopulmonary resuscitation and adjunctive VA-ECMO therapy. During hospitalization, pulmonary artery computed tomography angiography was performed to confirm the diagnosis of PE. Through anticoagulation management, mechanical ventilation, fluid management, and antibiotic treatment, five patients were successfully weaned from ECMO (83.33%), four patients survived for 30 d after discharge (66.67%), and two patients had good neurological outcomes (33.33%).

CONCLUSION

For patients with CA secondary to massive PE, ECPR in conjunction with heparin anticoagulation may improve outcomes.

Reperfusion therapies in pulmonary embolism-state of the art and expert opinion: A position paper from the "Unité de Soins Intensifs de Cardiologie" group of the French Society of Cardiology

Acute pulmonary embolism is a frequent cardiovascular emergency with an increasing incidence. The prognosis of patients with high-risk and intermediate-high-risk pulmonary embolism has not improved over the last decade. The current treatment strategies are mainly based on anticoagulation to prevent recurrence and reduce pulmonary vasculature obstruction. However, the slow rate of thrombus lysis under anticoagulation is unable to acutely decrease right ventricle overload and pulmonary vasculature resistance in patients with severe obstruction and right ventricle dysfunction. Therefore, patients with high-risk and intermediate-high-risk pulmonary embolism remain a therapeutic challenge. Reperfusion therapies may be discussed for these patients, and include systemic thrombolysis, catheter-directed therapies and surgical thrombectomy. High-risk patients require systemic thrombolysis, but may have contraindications as a result of the high risk of bleeding. In addition, intermediate-high-risk patients should not receive systemic thrombolysis, despite its high efficacy, because of prohibitive bleeding complications. Recently, percutaneous reperfusion techniques have been developed to acutely decrease pulmonary vascular obstruction with lower-dose or no thrombolytic agents and, thus, potentially higher safety than systemic thrombolysis. Some of these techniques improve key haemodynamic variables. Cardiac surgical techniques and venoarterial extracorporeal membrane oxygenation as temporary circulatory support may be useful in selected cases. The development of pulmonary embolism centres with multidisciplinary pulmonary embolism teams is mandatory to enable adequate use of reperfusion and improve outcomes. We aim to present the state of the art regarding reperfusion therapies in pulmonary embolism, but also to provide guidance on their indications and patient selection.

Update on Thrombolytic Therapy in Acute Pulmonary Thromboembolism

Thrombolytic treatment accelerates the dissolution of thrombus in acute pulmonary thromboembolism (PTE) and is potentially a lifesaving treatment. High-risk PTE is the clearest indication for this therapy, and its use in intermediate-risk cases is still controversial. A PTE response team may enable a rapid and effective determination of risk and treatment in these controversial clinical cases. Approved thrombolytic agents for the PTE treatment are streptokinase, urokinase, and alteplase. Currently, the most widely used agent is alteplase. It has a short infusion time (2 h) and a rapid effect. Newer, unapproved agents for the PTE treatment are tenecteplase and reteplase. The active resolution of thrombus via thrombolytic agents improves rapidly pulmonary perfusion, hemodynamic defect, gas exchange, and right ventricular dysfunction. However, it is important to determine appropriate candidates carefully, to prevent hemorrhage, which is the most important side effect of these drugs. Catheter-directed thrombolysis seems to be an alternative in patients not eligible for systemic thrombolytic therapy.

Use of extracorporeal membrane oxygenation in patients with acute high-risk pulmonary embolism: a case series with literature review

Background

Although extracorporeal membrane oxygenation (ECMO) has been used for the treatment of acute high-risk pulmonary embolism (PE), there are limited reports which focus on this approach. Herein, we described our experience with ECMO in patients with acute high-risk PE.

Methods

We retrospectively reviewed medical records of patients diagnosed with acute high-risk PE and treated with ECMO between January 2014 and December 2018.

Results

Among 16 patients included, median age was 51 years (interquartile range [IQR], 38 to 71 years) and six (37.5%) were male. Cardiac arrest was occurred in 12 (75.0%) including two cases of out-of-hospital arrest. All patients underwent veno-arterial ECMO and median ECMO duration was 1.5 days (IQR, 0.0 to 4.5 days). Systemic thrombolysis and surgical embolectomy were performed in seven (43.8%) and nine (56.3%) patients, respectively including three patients (18.8%) received both treatments. Overall 30-day mortality rate was 43.8% (95% confidence interval, 23.1% to 66.8%) and 30-day mortality rates according to the treatment groups were ECMO alone (33.3%, n=3), ECMO with thrombolysis (50.0%, n=4) and ECMO with embolectomy (44.4%, n=9).

Conclusions

Despite the vigorous treatment efforts, patients with acute high-risk PE were related to substantial morbidity and mortality. We report our experience of ECMO as rescue therapy for refractory shock or cardiac arrest in patients with PE.