Mechanical circulatory support devices and treatment strategies for right heart failure

Contemporary optimal therapeutic strategy with escalation/de-escalation of temporary mechanical circulatory support in patients with cardiogenic shock and advanced heart failure in Japan

The utilization of temporary mechanical circulatory support (MCS) in the management of cardiogenic shock is experiencing a notable surge. Acute myocardial infarction remains the predominant etiology of cardiogenic shock, followed by heart failure. Recent findings from the DanGer Shock trial indicate that the percutaneous micro-axial flow pump support, in conjunction with standard care, significantly reduced 6-month mortality in patients with acute myocardial infarction-related cardiogenic shock compared to those receiving standard care alone. However, real-world registry data reveal that the 30-day mortality among patients with acute myocardial infarction-related cardiogenic shock, who received concomitant veno-arterial extracorporeal membrane oxygenation support along with micro-axial flow pump, remain suboptimal. The persistent challenge in the field is how to incorporate, escalate, and de-escalate these temporary MCS to further improve clinical outcomes in such clinical scenarios. This review aims to elucidate the current practices surrounding the escalation and de-escalation of temporary MCS in real-world clinical settings and proposes considerations for future advancements in this critical area.

Pulmonary Artery Pressures and Mortality During Venoarterial ECMO: An ELSO Registry Analysis

BACKGROUND

Systemic hemodynamics and specific ventilator settings have been shown to predict survival during venoarterial extracorporeal membrane oxygenation (ECMO). How the right heart (the right ventricle and pulmonary artery) affect survival during venoarterial ECMO is unknown. We aimed to identify the relationship between right heart function with mortality and the duration of ECMO support.

METHODS

Cardiac ECMO runs in adults from the Extracorporeal Life Support Organization Registry between 2010 and 2022 were queried. Right heart function was quantified via pulmonary artery pulse pressure (PAPP) for pre-ECMO and on-ECMO periods. A multivariable model was adjusted for modified Society for Cardiovascular Angiography and Interventions stage, age, sex, and concurrent clinical data (ie, pulmonary vasodilators and systemic pulse pressure). The primary outcome was in-hospital mortality.

RESULTS

A total of 4442 ECMO runs met inclusion criteria and had documentation of hemodynamic and illness severity variables. The mortality rate was 55%; nonsurvivors were more likely to be older, have a worse Society for Cardiovascular Angiography and Interventions stage, and have longer pre-ECMO endotracheal intubation times (P<0.05 for all) than survivors. Increasing PAPP from pre-ECMO to on-ECMO time (ΔPAPP) was associated with reduced mortality per 2 mm Hg increase (odds ratio, 0.98 [95% CI, 0.97-0.99]; P=0.002). Higher on-ECMO PAPP was associated with mortality reduction across quartiles with the greatest reduction in the third PAPP quartile (odds ratio, 0.75 [95% CI, 0.63-0.90]; P=0.002) and longer time on ECMO per 10 mm Hg (beta, 15 [95% CI, 7.7-21]; P<0.001).

CONCLUSIONS

Early on-ECMO right heart function and interval improvement from pre-ECMO values were associated with mortality reduction during cardiac ECMO. Incorporation of right heart metrics into risk prediction models should be considered.

Extracorporeal Membrane Oxygenation for Respiratory Failure: A Narrative Review

Extracorporeal membrane oxygenation support for respiratory failure in the intensive care unit continues to have an expanded role in select patients. While acute respiratory distress syndrome remains the most common indication, extracorporeal membrane oxygenation may be used in other causes of refractory hypoxemia and/or hypercapnia. The most common configuration is veno-venous extracorporeal membrane oxygenation; however, in specific cases of refractory hypoxemia or right ventricular failure, some patients may benefit from veno-pulmonary extracorporeal membrane oxygenation or veno-venoarterial extracorporeal membrane oxygenation. Patient selection and extracorporeal circuit management are essential to successful outcomes. This narrative review explores the physiology of extracorporeal membrane oxygenation, indications and contraindications, ventilator management, extracorporeal circuit management, troubleshooting hypoxemia, complications, and extracorporeal membrane oxygenation weaning in patients with respiratory failure. As the footprint of extracorporeal membrane oxygenation continues to expand, it is essential that clinicians understand the underlying physiology and management of these complex patients.

Mechanical Circulatory Support Devices in Patients with High-Risk Pulmonary Embolism

Pulmonary embolism (PE) is a common acute cardiovascular condition. Within this review, we discuss the incidence, pathophysiology, and treatment options for patients with high-risk and massive pulmonary embolisms. In particular, we focus on the role of mechanical circulatory support devices and their possible therapeutic benefits in patients who are unresponsive to standard therapeutic options. Moreover, attention is given to device selection criteria, weaning protocols, and complication mitigation strategies. Finally, we underscore the necessity for more comprehensive studies to corroborate the benefits and safety of MCS devices in PE management.

Physiologic benefits of veno-pulmonary extracorporeal membrane oxygenation for COVID-19 ARDS: A single center experience

BACKGROUND

A subset of patients with COVID-19 acute respiratory distress syndrome (ARDS) require extracorporeal membrane oxygenation (ECMO). Veno-pulmonary (VP) ECMO provides support to the right ventricle and decreased risk of recirculation.

METHODS

A retrospective analysis of patients with COVID-19 ARDS and VP ECMO was performed. Patients were separated into groups by indication (1) "right ventricular (RV) failure," (2) "refractory hypoxemia," and (3) "recurrent suck-down events (SDEs)." Pre- and post-configuration vasoactive inotropic scores (VIS), fraction of inspired oxygen (FIO2), and resolution of SDEs were reported. A 90-day mortality was computed for all groups. Patients were also compared to those who underwent conventional venovenous (VV) ECMO.

RESULTS

Forty-seven patients underwent VP ECMO configuration, 18 in group 1, 16 in group 2, and 8 in group 3. Ninety-day mortality was 66% for the entire cohort and was 77.8%, 81.3% and 37.5% for groups 1, 2, and 3, respectively. Mean VIS decreased in group 1 (8.3 vs 2.9, p = 0.005), while mean FIO2 decreased in the group 2 and was sustained at 72 h (82.5% vs 52.5% and 47.5%, p < 0.001). Six of the eight (75%) of patients with recurrent SDEs had resolution of these events after configuration to VP ECMO. Patients with VP ECMO spent more days on ECMO (33 days compared to 18 days, p = 0.004) with no difference in mortality (66% compared to 55.1%, p = 0.28).

CONCLUSION

VP ECMO in COVID-19 ARDS improves hemodynamics in patients with RV failure, improves oxygenation in patients with refractory hypoxemia and improves the frequency of SDEs.

Medical and Mechanical Circulatory Support of the Failing Right Ventricle

PURPOSE OF REVIEW

To describe medical therapies and mechanical circulatory support devices used in the treatment of acute right ventricular failure.

RECENT FINDINGS

Experts have proposed several algorithms providing a stepwise approach to medical optimization of acute right ventricular failure including tailored volume administration, ideal vasopressor selection to support coronary perfusion, inotropes to restore contractility, and pulmonary vasodilators to improve afterload. Studies have investigated various percutaneous and surgically implanted right ventricular assist devices in several clinical settings. The initial management of acute right ventricular failure is often guided by invasive hemodynamic data tracking parameters of circulatory function with the use of pharmacologic therapies. Percutaneous microaxial and centrifugal extracorporeal pumps bypass the failing RV and support circulatory function in severe cases of right ventricular failure.

Pulmonary Artery Pressures and Mortality during VA ECMO: An ELSO Registry Analysis

Background

Systemic hemodynamics and specific ventilator settings have been shown to predict survival during venoarterial extracorporeal membrane oxygenation (VA ECMO). While these factors are intertwined with right ventricular (RV) function, the independent relationship between RV function and survival during VA ECMO is unknown.

Objectives

To identify the relationship between RV function with mortality and duration of ECMO support.

Methods

Cardiac ECMO runs in adults from the Extracorporeal Life Support Organization (ELSO) Registry between 2010 and 2022 were queried. RV function was quantified via pulmonary artery pulse pressure (PAPP) for pre-ECMO and on-ECMO periods. A multivariable model was adjusted for Society for Cardiovascular Angiography and Interventions (SCAI) stage, age, gender, and concurrent clinical data (i.e., pulmonary vasodilators and systemic pulse pressure). The primary outcome was in-hospital mortality.

Results

A total of 4,442 ECMO runs met inclusion criteria and had documentation of hemodynamic and illness severity variables. The mortality rate was 55%; non-survivors were more likely to be older, have a worse SCAI stage, and have longer pre-ECMO endotracheal intubation times (P < 0.05 for all) than survivors. Improving PAPP from pre-ECMO to on-ECMO time (Δ PAPP) was associated with reduced mortality per 10 mm Hg increase (OR: 0.91 [95% CI: 0.86-0.96]; P=0.002). Increasing on-ECMO PAPP was associated with longer time on ECMO per 10 mm Hg (Beta: 15 [95% CI: 7.7-21]; P<0.001).

Conclusions

Early improvements in RV function from pre-ECMO values were associated with mortality reduction during cardiac ECMO. Incorporation of Δ PAPP into risk prediction models should be considered.

Biventricular circulatory support using single-device and dual-device configurations: Initial pump characterization in simulated heart failure model

Objective

Severe biventricular heart failure (BHF) can be remedied using a biventricular assist device (BVAD). Two devices are currently in development: a universal ventricular assist device (UVAD), which will be able to assist either the left, right, or both ventricles, and a continuous-flow total artificial heart (CFTAH), which replaces the entire heart. In this study, the in vitro hemodynamic performances of two UVADs are compared to a CFTAH acting as a BVAD.

Methods

For this experiment, a biventricular mock circulatory loop utilizes two pneumatic pumps (Abiomed AB5000™, Danvers, MA, USA), in conjunction with a dual-output driver, to create heart failure (HF) conditions (left, LHF; right, RHF; biventricular, BHF). Systolic BHF for four different situations were replicated. In each situation, CFTAH and UVAD devices were installed and operated at two distinct speeds, and cannulations for ventricular and atrial connections were evaluated.

Results

Both CFTAH and UVAD setups achieved our recommended hemodynamic criteria. The dual-UVAD arrangement yielded a better atrial balance to alleviate LHF and RHF. For moderate and severe BHF scenarios, CFTAH and dual UVADs both created excellent atrial pressure balance. Conversely, when CFTAH was atrial cannulated for LHF and RHF, the needed atrial pressure balance was not met.

Conclusion

Comprehensive in vitro testing of two different BVAD setups exhibited self-regulation and exceptional pump performance for both (single- and dual-device) BHF support scenarios. For treating moderate and severe BHF, UVAD and CFTAH both functioned well with respect to atrial pressure regulation and cardiac output. Though, the dual-UVAD setup yielded a better atrial pressure balance in all BHF testing scenarios.