A Randomized Embedded Multifactorial Adaptive Platform for Extra Corporeal Membrane Oxygenation (REMAP ECMO) - Design and Rationale of the Left Ventricular Unloading trial domain

BACKGROUND

The use of Extracorporeal Membrane Oxygenation (ECMO) remains associated with high rates of complications, weaning failure and mortality which can be partly explained by a knowledge gap on how to properly manage patients on ECMO support. To address relevant patient management issues, we designed a "Randomized Embedded Multifactorial Adaptive Platform (REMAP)" in the setting of ECMO (REMAP ECMO) and a first embedded randomized controlled trial (RCT) investigating the effects of routine early left ventricular (LV) unloading through intra-aortic balloon pumping (IABP).

METHODS

REMAP ECMO describes a registry-based platform allowing for the embedding of multiple response adaptive RCTs (trial domains) which can perpetually address the effect of relevant patient management issues on ECMO weaning success. A first trial domain studies the effects of LV unloading by means of an IABP as an adjunct to veno-arterial (V-A) ECMO versus V-A ECMO alone on ECMO weaning success at 30 days in adult cardiogenic shock patients admitted to the Intensive Care Unit (ICU). The primary outcome of this trial is "successful weaning from ECMO" being defined as a composite of survival without the need for mechanical circulatory support, heart transplantation, or left ventricular assist device (LVAD) at 30 days after initiation of ECMO. Secondary outcomes include the need for interventional escalation of LV unloading strategy, mechanistic endpoints, survival characteristics until one year after ECMO initiation, and quality of life. Trial data will be analysed using a Bayesian statistical framework. The adaptive design allows for a high degree of flexibility, such as response adaptive randomization and early stopping of the trial for efficacy or futility. The REMAP ECMO LV unloading study is approved by the Medical Ethical Committee of the Erasmus Medical Center and is publicly registered.

CONCLUSION

This REMAP ECMO trial platform enables the efficient roll-out of multiple RCTs on relevant patient management issues. A first embedded trial domain will compare routine LV unloading by means of an IABP as an adjunct to V-A ECMO versus V-A ECMO alone.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05913622.

Different ECLS Pump Configurations for Temporary Right Ventricular Assist Device in LVAD Patients: A Retrospective Case-Control Study

BACKGROUND

Acute right ventricular failure is a critical complication after left ventricular assist device (LVAD) implantation, often managed with a temporary paracorporeal right ventricular assist device (RVAD). This study examined three extracorporeal life support (ECLS) systems regarding mortality, bleeding complications, and intensive care unit (ICU) stay duration.

METHODS

This monocentric, retrospective case-control study included all patients receiving LVAD with paracorporeal RVAD between 2009 and 2020. Three patient groups were formed: CentrimagTM (A), CardiohelpTM (B), and DeltastreamTM (C).

RESULTS

A total of 245 patients were included. Preoperative parameters were similar between the CentrimagTM and DeltastreamTM groups, but CardiohelpTM patients had worse Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Scores (A: 1.7 ± 0.8, B: 1.36 ± 0.5, C: 1.9 ± 0.9; p < 0.05). In-hospital death rates were A: 61 (41.8%), B: 15 (32.6%), C: 29 (54.7%); p < 0.05, and reoperation due to bleeding rates were A: 32 (21.9%), B: 8 (17.4%), C: 25 (47.2%); p < 0.05, with the DeltastreamTM group showing the highest rates. This group also had increased thrombocyte consumption and prolonged ICU stays.

CONCLUSIONS

Temporary RVADs lead to bleeding complications, affecting patient outcomes. The DeltastreamTM group had significantly higher bleeding complications, likely due to high pump revolution rates and thrombocyte decline. Due to the study's retrospective nature and complex patient profiles, these interesting findings should be validated in future studies.

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.

Adult Highlights From the Extracorporeal Life Support Organization Registry: 2017-2022

The Extracorporeal Life Support Organization (ELSO) registry captures clinical data and outcomes on patients receiving extracorporeal membrane oxygenation (ECMO) support across the globe at participating centers. It provides a very unique opportunity to benchmark outcomes and analyze the clinical course to help identify ways of improving patient outcomes. In this review, we summarize select adult ECMO articles published using the ELSO registry over the past 5 years. These articles highlight innovative utilization of the registry data in generating hypotheses for future clinical trials. Members of the ELSO Scientific Oversight Committee can be found here: https://www.elso.org/registry/socmembers.aspx .

Patient-centered weaning from venoarterial extracorporeal membrane oxygenation: "A practice-oriented narrative review of literature"

Venoarterial extracorporeal membrane oxygenation (V-A ECMO) is increasingly used in cardiogenic shock for rapid stabilization and bridging towards recovery, long-term mechanical circulatory support or transplant. Although technological advances have instigated its widespread use, the complex, long-lasting ECMO care creates a significant strain on hospital staff and resources. Therefore, optimal clinical management including timely decisions on ECMO removal and further therapy are pivotal, yet require a well-structured weaning approach. Although dedicated guidelines are lacking, a variety of weaning protocols have distillated echocardiographic and hemodynamic predictors for successful weaning. Nevertheless, a strikingly high mortality up to 70% after initial successful weaning raises concerns about the validity of current weaning strategies. Here, we plead for a patient-tailored approach including a bailout strategy when weaning fails. This should account not only for left- but also right ventricular function and interdependence, as well as the temporal course of cardiac recovery in function of extracorporeal support. Patients with a high risk of weaning failure should be identified early, enabling timely transportation to an advanced heart failure center. This review summarizes predictors of successful weaning and discusses all relevant elements for a structured weaning approach with a central role for patient-specific clinical considerations and echocardiography.

Targeting the contact system in a rabbit model of extracorporeal membrane oxygenation

Previous studies suggested that contact pathway factors drive thrombosis in mechanical circulation. We used a rabbit model of veno-arterial extracorporeal circulation (VA-ECMO) to evaluate the role of factors XI and XII in ECMO-associated thrombosis and organ damage. Factors XI and XII (FXI, FXII) were depleted using established antisense oligonucleotides before placement on a blood-primed VA-ECMO circuit. Decreasing FXII or FXI to < 5% of baseline activity significantly prolonged ECMO circuit lifespan, limited the development of coagulopathy, and prevented fibrinogen consumption. Histological analysis suggested that FXII depletion mitigated interstitial pulmonary edema and hemorrhage whereas heparin and FXI depletion did not. Neither FXI nor FXII depletion was associated with significant hemorrhage in other organs. In vitro analysis showed that membrane oxygenator fibers (MOFs) alone are capable of driving significant thrombin generation in a FXII- and FXI-dependent manner. MOFs also augment thrombin generation triggered by low (1 pM) or high (5 pM) tissue factor concentrations. However, only FXI elimination completely prevented the increase in thrombin generation driven by MOFs, suggesting MOFs augment thrombin-mediated FXI activation. Together, these results suggest that therapies targeting FXII or FXI limit thromboembolic complications associated with ECMO. Further studies are needed to determine the contexts wherein targeting FXI and FXII, either alone or in combination, would be most beneficial in ECMO. Moreover, studies are also needed to determine the potential mechanisms coupling FXII to end-organ damage in ECMO.

Unloading the Left Ventricle in Venoarterial ECMO: In Whom, When, and How?

Venoarterial extracorporeal membrane oxygenation provides cardiorespiratory support to patients in cardiogenic shock. This comes at the cost of increased left ventricle (LV) afterload that can be partly ascribed to retrograde aortic flow, causing LV distension, and leads to complications including cardiac thrombi, arrhythmias, and pulmonary edema. LV unloading can be achieved by using an additional circulatory support device to mitigate the adverse effects of mechanical overload that may increase the likelihood of myocardial recovery. Observational data suggest that these strategies may improve outcomes, but in whom, when, and how LV unloading should be employed is unclear; all techniques require balancing presumed benefits against known risks of device-related complications. This review summarizes the current evidence related to LV unloading with venoarterial extracorporeal membrane oxygenation.

Acute lung injury and recovery in patients with refractory VT/VF cardiac arrest treated with prolonged CPR and veno-arterial extracorporeal membrane oxygenation

AIM

Describe the lung injury patterns among patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest (VT/VF OHCA) supported with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) facilitated resuscitation.

METHODS

In this retrospective single-center cohort study including VT/VF OHCA patients supported with VA ECMO, we compared OHCA characteristics, post-arrest computed tomography (CT) scans, ventilator parameters, and other lung-related pathology between survivors, patients who developed brain death, and those with other causes of death.

RESULTS

Among 138 patients, 48/138 (34.8%) survived, 31/138 (22.4%) developed brain death, and 59/138 (42.7%) died of other causes. Successful extubation was achieved in 39/138 (28%) with a median time to extubation of 8.0 days (6.0, 11.0) in those who survived. Tracheostomy was required in 15/48 (31.3%) survivors. Chest CT obtained on all patients showed lung injury in at least one lung area in 124/135 (91.8%) patients, predominantly in the dependent posterior areas. There was no association between the number of affected areas and survival. Lung compliance was low on admission [26 (19,33) ml/cmH₂0], improved throughout hospitalization (p = 0.03), and recovered faster in survivors compared to those who died (p < 0.001). VA-ECMO allowed the use of lung-protective ventilation while maintaining normalized PaO₂ and PaCO₂. Patients treated with V-A ECMO and either IABP or Impella had lower pulmonary compliance and more affected areas on their CT compared to those treated with V-A ECMO alone.

CONCLUSIONS

Lung injury is common among patients with refractory VT/VF OHCA requiring V-A ECMO, but imaging severity is not associated with survival. Reductions in lung compliance accompany post-arrest lung injury while compliance recovery is associated with survival.

The ABCDE approach to difficult weaning from venoarterial extracorporeal membrane oxygenation

Venoarterial extracorporeal membrane oxygenation (VA ECMO) has been increasingly applied in patients with cardiogenic shock in recent years. Nevertheless, many patients cannot be successfully weaned from VA ECMO support and 1-year mortality remains high. A systematic approach could help to optimize clinical management in favor of weaning by identifying important factors in individual patients. Here, we provide an overview of pivotal factors that potentially prevent successful weaning of VA ECMO. We present this through a rigorous approach following the relatable acronym ABCDE, in order to facilitate widespread use in daily practice.

Prevention and treatment of pulmonary congestion in patients undergoing venoarterial extracorporeal membrane oxygenation for cardiogenic shock

Cardiogenic shock is still a major driver of mortality on intensive care units and complicates ∼10% of acute coronary syndromes with contemporary mortality rates up to 50%. In the meantime, percutaneous circulatory support devices, in particular venoarterial extracorporeal membrane oxygenation (VA-ECMO), have emerged as an established salvage intervention for patients in cardiogenic shock. Venoarterial extracorporeal membrane oxygenation provides temporary circulatory support until other treatments are effective and enables recovery or serves as a bridge to ventricular assist devices, heart transplantation, or decision-making. In this critical care perspective, we provide a concise overview of VA-ECMO utilization in cardiogenic shock, considering rationale, critical care management, as well as weaning aspects. We supplement previous literature by focusing on therapeutic issues related to the vicious circle of retrograde aortic VA-ECMO flow, increased left ventricular (LV) afterload, insufficient LV unloading, and severe pulmonary congestion limiting prognosis in a relevant proportion of patients receiving VA-ECMO treatment. We will outline different modifications in percutaneous mechanical circulatory support to meet this challenge. Besides a strategy of running ECMO at lowest possible flow rates, novel therapeutic options including the combination of VA-ECMO with percutaneous microaxial pumps or implementation of a venoarteriovenous-ECMO configuration based on an additional venous cannula supplying towards pulmonary circulation are most promising among LV unloading and venting strategies. The latter may even combine the advantages of venovenous and venoarterial ECMO therapy, providing potent respiratory and circulatory support at the same time. However, whether VA-ECMO can reduce mortality has to be evaluated in the urgently needed, ongoing prospective randomized studies EURO-SHOCK (NCT03813134), ANCHOR (NCT04184635), and ECLS-SHOCK (NCT03637205). These studies will provide the opportunity to investigate indication, mode, and effect of LV unloading in dedicated sub-analyses. In future, the Heart Teams should aim at conducting a dedicated randomized trial comparing VA-ECMO support with vs. without LV unloading strategies in patients with cardiogenic shock.

New challenges in cardiac intensive care units

Critical care cardiology is a steadily and rapidly developing sub-specialization within cardiovascular medicine, since the first emergence of a coronary care unit in the early 1960s. Today, modern cardiac intensive care units (CICU) serve a complex patient population with a high burden of cardiovascular and non-cardiovascular critical illnesses. Treatment of these patients requires a multidisciplinary approach, with a combination of highly specialized knowledge and skills in cardiovascular diseases, as well as emergency, critical-care and internal medicine. The CICU has always posed special challenges to both experienced intensivists as well as fellows-in-training (FIT) and is certainly one of the most demanding training phases. In recent years, these challenges have grown significantly owing to technological innovations, with new and steadily rising numbers of complex interventional procedures and new options for temporary circulatory support for critically ill patients, such as venoarterial extracorporeal membrane oxygenation (VA-ECMO). Herein, we focus on the successful CICU management of these special patient cohorts, which must become an integral part of critical-care training.

Transition From Temporary to Durable Circulatory Support Systems

BACKGROUND

The decision to implant durable mechanical circulatory systems (MCSs) in patients on extracorporeal life support (ECLS) is challenging due to expected poor outcomes in these patients.

OBJECTIVES

The aim of this study was to identify outcome predictors that may facilitate future patient selection and decision making.

METHODS

The Durable MCS after ECLS registry is a multicenter retrospective study that gathered data on consecutive patients who underwent MCS implantation after ECLS between January 2010 and August 2018 in 11 high-volume European centers. Several perioperative parameters were collected. The primary endpoint was survival at 1 year after durable MCS implantation.

RESULTS

A total of 531 durable MCSs after ECLS were implanted during this period. The average patient age was 53 ± 12 years old. ECLS cannulation was peripheral in 87% of patients and 33% of the patients had history of cardiopulmonary resuscitation before ECLS implantation. The 30-day, 1-year, and 3-year actuarial survival rates were 77%, 53%, and 43%, respectively. The following predictors for 1-year outcome have been observed: age, female sex, lactate value, Model of End-Stage Liver Disease XI score, history of atrial fibrillation, redo surgery, and body mass index >30 kg/m². On the basis of this data, a risk score and an app to estimate 1-year mortality was created.

CONCLUSIONS

The outcome in patients receiving durable MCS after ECLS remains limited, yet preoperative factors may allow differentiating futile patients from those with significant survival benefit.

Utility of transesophageal echocardiography to assess real time left atrial pressure changes and dynamic mitral regurgitation following placement of transseptal multistage venous cannula for systemic venous drainage and indirect left ventricular venting in venoarterial extracorporeal membrane oxygenation

A patient with heart failure due to nonischemic cardiomyopathy presented as a transfer to our institution following peripheral (femoral) venoarterial (VA) extracorporeal membrane oxygenation (ECMO) placement. With peripheral VA ECMO cannulation, the patient continued to have unstable ventricular tachyarrhythmias. Echocardiography demonstrated left ventricular (LV) dilation and severe mitral regurgitation (MR) with clinical and chest X-ray evidence of pulmonary edema. To provide venous drainage and simultaneous decompression of the left atrium (LA) and thereby indirect LV venting, a single multistage venous cannula was placed across the inter-atrial septum (IAS) using the previously described left atrial venoarterial (LA-VA) ECMO cannulation technique. Two- and three-dimensional (3D) transesophageal echocardiography (TEE) demonstrated utility in guiding cannula placement into the appropriate position and providing real time assessment of ventricular decompression and MR severity. There was subsequent improvement in pulmonary edema. This case is thought to be the first demonstration of real time resolution of pulmonary venous flow reversal in a patient undergoing LA-VA ECMO cannulation. This demonstration offers important mechanistic insight into some of the potential benefits of such an approach.

A mini-thoracotomy approach for walking veno-arterial extracorporeal membranous oxygenation

Fulminant myocarditis is a rapidly progressive myocardial inflammation that commonly requires advanced circulatory support therapies. We report our management of a 36-year-old gentleman with fulminant myocarditis who we managed with extracorporeal membranous oxygenation (ECMO) and subsequently durable bi-ventricular assist devices as a bridge to heart transplantation. The patient was admitted after a 1-week history of malaise with severe lethargy, jugular venous distension to greater than 10 cm, and troponin elevation to greater than 27 K. He was taken immediately for a heart catheterization which showed no obstructive coronary disease, and hemodynamics consistent with bi-ventricular failure. We proceeded with ECMO for hemodynamic support, utilizing a mini-thoracotomy for cannulation. A Protek Duo Rapid Deployment (LivaNova) was inserted via a modified Seldinger technique through the left ventricular apex, terminating in the ascending aorta. Percutaneous right IJ bicaval via a y-ed Avalon Elite (Getinge) was employed for venous drainage. This case highlights an alternate strategy for central walking veno-arterial ECMO in a patient presenting with fulminant myocarditis with a platform that minimizes upper/lower extremity over/under perfusion complications, while providing sternal sparring antegrade arterial flow with simultaneous ventricular unloading/venting.

Financial implications of using extracorporeal membrane oxygenation following heart transplantation

OBJECTIVES

Primary graft dysfunction after heart transplant is associated with high morbidity and mortality. Extracorporeal membrane oxygenation (ECMO) can be used to wean patients from cardiopulmonary bypass. This study retrospectively reviews a single-centre experience of post-transplant ECMO in regard to outcomes and associated costs.

METHODS

Between May 2006 and May 2019, a total of 267 adult heart transplants were performed. We compared donor and recipient variables, ECMO duration and the incidence of renal failure, bleeding, infection and cost analysis between ECMO and non-ECMO groups.

RESULTS

ECMO support was required postoperatively to manage primary graft dysfunction in 72 (27%) patients. The mean duration of ECMO support was 6 ± 3.2 days. Mean ischaemic times were similar between the groups. There was a significantly higher proportion of ventricular assist device explant to transplant in the ECMO group versus non-ECMO (38.2% vs 14.1%; P < 0.0001). ECMO patients had a longer duration of stay in the intensive care unit (P < 0.0001) and total hospital stay (P < 0.0001). Greater mortality was observed in the ECMO group (P < 0.0001). The median cost of providing ECMO was £18 000 [interquartile range (IQR): £12 750-£24 000] per patient with an additional median £35 225 (IQR: £21 487.25-£51 780.75) for ITU stay whilst on ECMO. The total median cost per patient inclusive of hospital stay, ECMO and dialysis costs was £65 737.50 (IQR: £52 566.50-£95 221.75) in the non-ECMO group compared to £145 415.71 (IQR: £102 523.21-£200 618.96) per patient in the ECMO group (P < 0.0001).

CONCLUSIONS

Patients with primary graft dysfunction following heart transplantation who require ECMO are frequently bridged to a recovery; however, the medium and longer-term survival for these patients is poorer than for patients who do not require ECMO.

Hemodynamic adaptation of heart failure to percutaneous venoarterial extracorporeal circulatory supports

Extracorporeal life support (ECLS) is a treatment modality that provides prolonged blood circulation, gas exchange and can partially support or fully substitute functions of heart and lungs in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Due to high-volume bypass, the extracorporeal flow is interacting with native cardiac output. The pathophysiology of circulation and ECLS support reveals significant effects on arterial pressure waveforms, cardiac hemodynamics, and myocardial perfusion. Moreover, it is still subject of research, whether increasing stroke work caused by the extracorporeal flow is accompanied by adequate myocardial oxygen supply. The left ventricular (LV) pressure-volume mechanics are reflecting perfusion and loading conditions and these changes are dependent on the degree of the extracorporeal blood flow. By increasing the afterload, artificial circulation puts higher demands on heart work with increasing myocardial oxygen consumption. Further, this can lead to LV distention, pulmonary edema, and progression of heart failure. Multiple methods of LV decompression (atrial septostomy, active venting, intra-aortic balloon pump, pulsatility of flow) have been suggested to relieve LV overload but the main risk factors still remain unclear. In this context, it has been recommended to keep the rate of circulatory support as low as possible. Also, utilization of detailed hemodynamic monitoring has been suggested in order to avoid possible harm from excessive extracorporeal flow.

Outcomes of percutaneous temporary biventricular mechanical support: a systematic review

Percutaneous biventricular assist devices (BiVAD) are a recently developed treatment option for severe cardiogenic shock. This systematic review sought to identify indications and outcomes of patients placed on percutaneous BiVAD support. An electronic search was performed to identify all appropriate studies utilizing a percutaneous BiVAD configuration. Fifteen studies comprising of 20 patients were identified. Individual patient survival and outcomes data were combined for statistical analysis. All 20 patients were supported with a microaxial LVAD, 12/20 (60%) of those patients were supported with a microaxial (RMA) right ventricular assist device (RVAD), and the remaining 8/20 (40%) patients were supported with a centrifugal extracorporeal RVAD (RCF). All patients presented with cardiogenic shock, and of these, 12/20 (60%) presented with a non-ischemic etiology vs 8/20 (40%) with ischemic disease. For the RMA group, RVAD support was significantly longer [RMA 5 (IQR 4-7) days vs RCF 1 (IQR 1-2) days, p = 0.03]. Intravascular hemolysis post-BiVAD occurred in three patients (27.3%) [RMA 3 (33.3%) vs RCF 0 (0%), p = 0.94]. Five patients received a durable left ventricular assist device, one patient received a total artificial heart, and one patient underwent a heart transplantation. Estimated 30-day mortality was 15.0%, and 78.6% were discharged alive. Both strategies for percutaneous BiVAD support appear to be viable options for severe cardiogenic shock.

Pulmonary complications associated with veno-arterial extra-corporeal membrane oxygenation: a comprehensive review

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a life-saving technology that provides transient respiratory and circulatory support for patients with profound cardiogenic shock or refractory cardiac arrest. Among its potential complications, VA-ECMO may adversely affect lung function through various pathophysiological mechanisms. The interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response which may increase pulmonary vascular permeability and promote the sequestration of polymorphonuclear neutrophils within the lung parenchyma. Also, VA-ECMO increases the afterload of the left ventricle (LV) through reverse flow within the thoracic aorta, resulting in increased LV filling pressure and pulmonary congestion. Furthermore, VA-ECMO may result in long-standing pulmonary hypoxia, due to partial shunting of the pulmonary circulation and to reduced pulsatile blood flow within the bronchial circulation. Ultimately, these different abnormalities may result in a state of persisting lung inflammation and fibrotic changes with concomitant functional impairment, which may compromise weaning from VA-ECMO and could possibly result in long-term lung dysfunction. This review presents the mechanisms of lung damage and dysfunction under VA-ECMO and discusses potential strategies to prevent and treat such alterations.

Increasing venoarterial extracorporeal membrane oxygenation flow puts higher demands on left ventricular work in a porcine model of chronic heart failure

Background

Venoarterial extracorporeal membrane oxygenation (VA ECMO) is widely used in the treatment of circulatory failure, but repeatedly, its negative effects on the left ventricle (LV) have been observed. The purpose of this study is to assess the influence of increasing extracorporeal blood flow (EBF) on LV performance during VA ECMO therapy of decompensated chronic heart failure.

Methods

A porcine model of low-output chronic heart failure was developed by long-term fast cardiac pacing. Subsequently, under total anesthesia and artificial ventilation, VA ECMO was introduced to a total of five swine with profound signs of chronic cardiac decompensation. LV performance and organ specific parameters were recorded at different levels of EBF using a pulmonary artery catheter, a pressure–volume loop catheter positioned in the LV, and arterial flow probes on systemic arteries.

Results

Tachycardia-induced cardiomyopathy led to decompensated chronic heart failure with mean cardiac output of 2.9 ± 0.4 L/min, severe LV dilation, and systemic hypoperfusion. By increasing the EBF from minimal flow to 5 L/min, we observed a gradual increase of LV peak pressure from 49 ± 15 to 73 ± 11 mmHg (P = 0.001) and an improvement in organ perfusion. On the other hand, cardiac performance parameters revealed higher demands put on LV function: LV end-diastolic pressure increased from 7 ± 2 to 15 ± 3 mmHg, end-diastolic volume increased from 189 ± 26 to 218 ± 30 mL, end-systolic volume increased from 139 ± 17 to 167 ± 15 mL (all P < 0.001), and stroke work increased from 1434 ± 941 to 1892 ± 1036 mmHg*mL (P < 0.05). LV ejection fraction and isovolumetric contractility index did not change significantly.

Conclusions

In decompensated chronic heart failure, excessive VA ECMO flow increases demands and has negative effects on the workload of LV. To protect the myocardium from harm, VA ECMO flow should be adjusted with respect to not only systemic perfusion, but also to LV parameters.

Strategies of left ventricular unloading during VA-ECMO support: a network meta-analysis

BACKGROUND

Left ventricle (LV) unloading during VenoArterial ExtraCorporeal Membrane Oxygenation (VA-ECMO) reduces the risk of LV distention, stagnation and pulmonary congestion resulting from the increased afterload. Lacking direct comparisons between unloading strategies we used network meta-analysis to indirectly compare different unloading approaches.

METHODS

A literature research was performed to include all studies on VA-ECMO reporting data on mechanical LV unloading. The pre-specified outcome was in-hospital death.

RESULTS

Literature search identified 389 studies: 16 were included in the analysis (3930 patients). Two strategies of mechanical LV unloading were compared: afterload reduction (IABP) and preload reduction (Impella pump, right upper pulmonary/trans-septal catheters, LV surgical vents). Any LV unloading strategy was associated with mortality reduction with overall OR = 0.54; 95% CI 0.42-0.70; p < .001. Targeting afterload was associated with reduced mortality (OR = 0.61 95% CI 0.46-0.81; p < .001; I² = 61%), as targeting preload (OR = 0.34 95% CI 0.21-0.55; p < .001; I² = 0%). Significant between group difference was observed (p = .04): to further explore this we performed a network meta-analysis. Indirect comparisons between afterload and preload reduction were estimated. Any unloading technique was confirmed better than none but preload targeting resulted better than afterload targeting.

CONCLUSION

Any unloading strategy in VA-ECMO patients was associated with lower mortality as compared to no-unloading. Preload reduction strategies resulted superior to afterload reduction.

Pulmonary artery pressure may be a predictor of closed aortic valve in patients managed by venoarterial extracorporeal membrane oxygenation

In the management of venoarterial extracorporeal membrane oxygenation, some patients present persistently closed aortic valve. However, little is known about the variables that contribute to persistently closed aortic valve. We investigated the factors that could predict persistently closed aortic valve at the time of venoarterial extracorporeal membrane oxygenation initiation. We investigated 17 patients who presented closed aortic valve immediately after the introduction of venoarterial extracorporeal membrane oxygenation. Patients who presented closed aortic valve 24 h after introduction of venoarterial extracorporeal membrane oxygenation were defined as the Closed-AV group (n = 8), while those whose aortic valve remained opened after 24 h were defined as the Open-AV group (n = 9). All patients were managed by concomitant use of intra-aortic balloon pumping. At baseline, there were no significant differences between mean arterial blood pressure, central venous pressure, and left ventricular ejection fraction. However, Closed-AV group had significantly lower mean pulmonary artery pressure and pulmonary artery pulse pressure compared to those of Open-AV group (mean pulmonary artery pressure: 15 ± 6 mmHg vs 25 ± 8 mmHg, p = 0.01; pulmonary artery pulse pressure: 3 ± 2 mmHg vs 8 ± 3 mmHg, p < 0.01). Logistic regression analyses revealed that the lower mean pulmonary artery pressure and pulmonary artery pulse pressure had the predictive value of closed aortic valve within 24 h after venoarterial extracorporeal membrane oxygenation initiation (mean pulmonary artery pressure: odds ratio = 0.78, 95% confidence interval = 0.58-0.95, p < 0.01; pulmonary artery pulse pressure: odds ratio = 0.18, 95% confidence interval = 0.01-0.61, p < 0.01). Lower mean pulmonary artery pressure and pulmonary artery pulse pressure values could predict persistent closed aortic valve 24 h after venoarterial extracorporeal membrane oxygenation initiation. Left ventricular preload derived from right heart function may have a major impact on aortic valve status.

Predictors of in-hospital mortality and midterm outcomes of patients successfully weaned from venoarterial extracorporeal membrane oxygenation

OBJECTIVES

There is limited evidence to guide the decision to proceed with weaning from venoarterial extracorporeal membrane oxygenation, and approximately 30% of patients weaned "successfully" do not survive to hospital discharge. We evaluated predictors of in-hospital mortality and midterm outcomes of patients successfully weaned from venoarterial extracorporeal membrane oxygenation after support for cardiogenic shock, surviving more than 24 hours after weaning, with the aim of improving patient selection for durable weaning.

METHODS

We performed a retrospective analysis of 92 patients supported on venoarterial extracorporeal membrane oxygenation and successfully weaned between January 2013 and February 2018. Survival was estimated by the Kaplan-Meier method. Predictors of in-hospital mortality were identified using a Cox proportional hazards model and an Akaike information criterion-selected multivariate model.

RESULTS

Overall survival at hospital discharge was 64.2%; survival was 54.6% 1 year after support and 51.4% 3 years after support. A history of diabetes, previous myocardial infarction, prolonged extracorporeal membrane oxygenation support, and hypoxemia at extracorporeal membrane oxygenation weaning were independent predictors of in-hospital mortality. At midterm follow-up, New York Heart Association class I heart function was observed in 53% of patients, class II in 19%, class III in 16%, and class IV in 12%. Average left ventricular ejection fraction was 46.5% ± 18.2%, and 50% of the patients had been readmitted to the hospital because of heart failure.

CONCLUSIONS

Durable extracorporeal membrane oxygenation weaning with acceptable midterm functional status is obtainable in well-selected patients. Previous myocardial infarction, diabetes, prolonged extracorporeal membrane oxygenation support, and pulmonary dysfunction strongly predicted in-hospital mortality after venoarterial extracorporeal membrane oxygenation weaning. In this high-risk situation, other heart replacement therapies should be considered.

Venoarterial Extracorporeal Membrane Oxygenation in Cardiogenic Shock: Lifeline of Modern Day CICU

Cardiogenic shock (CS) portends an extremely high mortality of nearly 50% during index hospitalization. Prompt diagnoses of CS, its underlying etiology, and efficient implementation of treatment modalities, including mechanical circulatory support (MCS), are critical especially in light of such high predicted mortality. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides the most comprehensive cardiopulmonary support in critically ill patients and hence has seen a steady increase in its utilization over the past decade. Hence, a good understanding of VA-ECMO, its role in treatment of CS, especially when compared with other temporary MCS devices, and its complications are vital for any critical care cardiologist. Our review of VA-ECMO aims to provide the same.

Medical Optimization and Liberation of Adult Patients From VA-ECMO

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) can be an efficacious cardiopulmonary support for adults as rescue from refractory cardiogenic shock. It is best employed as a bridging strategy to recovery or alternative support rather than sustained, long-term mechanical circulatory support. The purpose of this paper is to discuss strategies to optimize patient management on VA-ECMO and approaches to promote successful separation from support. Rapid medical optimization will assist in reducing the time on VA-ECMO, thereby improving the likelihood of patient salvage. Suitably trained physicians and personnel, guided by structured protocols, can promote excellence in team care and provision of consistent management. Focusing on anticoagulation, careful neurologic monitoring, prevention of leg ischemia, awareness of differential hypoxemia, optimizing mechanical ventilation, identifying and timely intervention for left-ventricular distension (LVD), along with a strategic weaning algorithm, can prevent significant morbidity and mortality. LVD physiology, diagnosis, and risk factors are reviewed. Indications for LV decompression, along with medical and mechanical management options, are elucidated.

2019 EACTS Expert Consensus on long-term mechanical circulatory support

Long-term mechanical circulatory support (LT-MCS) is an important treatment modality for patients with severe heart failure. Different devices are available, and many-sometimes contradictory-observations regarding patient selection, surgical techniques, perioperative management and follow-up have been published. With the growing expertise in this field, the European Association for Cardio-Thoracic Surgery (EACTS) recognized a need for a structured multidisciplinary consensus about the approach to patients with LT-MCS. However, the evidence published so far is insufficient to allow for generation of meaningful guidelines complying with EACTS requirements. Instead, the EACTS presents an expert opinion in the LT-MCS field. This expert opinion addresses patient evaluation and preoperative optimization as well as management of cardiac and non-cardiac comorbidities. Further, extensive operative implantation techniques are summarized and evaluated by leading experts, depending on both patient characteristics and device selection. The faculty recognized that postoperative management is multidisciplinary and includes aspects of intensive care unit stay, rehabilitation, ambulatory care, myocardial recovery and end-of-life care and mirrored this fact in this paper. Additionally, the opinions of experts on diagnosis and management of adverse events including bleeding, cerebrovascular accidents and device malfunction are presented. In this expert consensus, the evidence for the complete management from patient selection to end-of-life care is carefully reviewed with the aim of guiding clinicians in optimizing management of patients considered for or supported by an LT-MCS device.

The Starling Relationship and Veno-Arterial ECMO: Ventricular Distension Explained

The use of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) to support patients with acute heart failure has been associated with ventricular distension and pulmonary edema, the mechanism of which is not fully understood. This study examined the impact of VA ECMO on left ventricular (LV) Starling curves to elaborate a framework for anticipating and treating LV distension. A previously developed and validated model of the cardiovascular system was used to generate pressure-volume (PV) loops and Starling curves while holding mean arterial pressure (mABP) constant at a range of values either by adjusting systemic resistance or by adding VA ECMO support. It was found that under all conditions of similar mAPB, the Starling curve was unchanged; therefore, the degree of LV distension is obligated by the mAPB (irrespective of whether controlled pharmacologically with or without ECMO support and independent of heart rate), LV contractility, and target stroke volume. The Starling relationship provides a conceptual framework for understanding the risk and treatment of LV distension during VA ECMO support.

Choosing Between Left Ventricular Assist Devices and Biventricular Assist Devices

Right ventricular failure following left ventricular assist devices implantation is a serious complication associated with high mortality. In patients with or at high risk of developing right ventricular failure, biventricular support is recommended. Because univentricular support is associated with high survival rates, biventricular support is often undertaken as a last resort. With the advent of newer right ventricular and biventricular systems under design and testing, better differentiation is required to ensure optimal patients care. Clear guidelines on patient selection, time of intervention and device selection are required to improve patient outcomes.

Cardiac catheterization and percutaneous intervention procedures on extracorporeal membrane oxygenation support

Extracorporeal membrane oxygenation (ECMO) is used to support critically ill patients when conventional therapies have failed. ECMO has been available for four decades and has gained use as a rescue therapy in severe refractory hypoxic disorders and in patients with refractory cardiogenic shock (RCS). Over recent years, several percutaneous cardiac interventions and implant devices have been developed that are now used frequently in conjunction with ECMO in order to maintain organ perfusion. Here, we review the literature on VA-ECMO cannulation location, the use of VA-ECMO in interventions (e.g., coronary interventions and structural heart interventions) and percutaneous cardiac device implantation in VA-ECMO recipients with RCS.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.

Left ventricular unloading during veno-arterial ECMO: a review of percutaneous and surgical unloading interventions

Short-term mechanical support by veno-arterial extracorporeal membrane oxygenation (VA ECMO) is more and more applied in patients with severe cardiogenic shock. A major shortcoming of VA ECMO is its variable, but inherent increase of left ventricular (LV) mechanical load, which may aggravate pulmonary edema and hamper cardiac recovery. In order to mitigate these negative sequelae of VA ECMO, different adjunct LV unloading interventions have gained a broad interest in recent years. Here, we review the whole spectrum of percutaneous and surgical techniques combined with VA ECMO reported to date.

Extracorporeal life support in cardiogenic shock: indications and management in current practice

Veno-arterial extracorporeal life support (VA-ECLS) provides circulatory and respiratory stabilisation in patients with severe refractory cardiogenic shock. Although randomised controlled trials are lacking, the use of VA-ECLS is increasing and observational studies repeatedly have shown treatment benefits in well-selected patients. Current clinical challenges in VA-ECLS relate to optimal management of the individual patient on extracorporeal support given its inherent complexity. In this review article we will discuss indications, daily clinical management and complications of VA-ECLS in cardiogenic shock refractory to conventional treatment strategies.

Pulmonary arteriovenous extracorporeal membrane oxygenation to avoid pulmonary overflow during total artificial heart implantation

Total artificial hearts (TAH) can be used as a bridge to transplant or, occasionally, as destination therapy for patients with severe biventricular dysfunction. Not infrequently TAHs are placed in patients with severe low flow states, in which the lungs of these patients are unable to adjust rapidly to the "normal" right ventricular output of a TAH. These patients may develop variable degrees of pulmonary edema secondary to stress failure of the pulmonary capillaries requiring increased respiratory support, which can occasionally be fatal. In this "how to do it" article, we describe the technique for a pulmonary arteriovenous extracorporeal membrane oxygenation with TAH to avoid sudden pulmonary overflow and gradually expose the lungs to increasing flow.

Advanced Percutaneous Mechanical Circulatory Support Devices for Cardiogenic Shock

OBJECTIVES

To review temporary percutaneous mechanical circulatory support devices for the treatment of cardiogenic shock, including current evidence, contraindications, complications, and future directions.

DATA SOURCES

A MEDLINE search was conducted with MeSH terms: cardiogenic shock, percutaneous mechanical circulatory support, extracorporeal membrane oxygenation, Impella, and TandemHeart.

STUDY SELECTION

Selected publications included randomized controlled trial data and observational studies describing experience with percutaneous mechanical circulatory support in cardiogenic shock.

DATA EXTRACTION

Studies were chosen based on strength of association with and relevance to cardiogenic shock.

DATA SYNTHESIS

Until recently, there were few options if cardiogenic shock was refractory to vasopressors or intra-aortic balloon pump counterpulsation. Now, several percutaneous mechanical circulatory support devices, including Impella (Abiomed, Danvers, MA), TandemHeart (CardiacAssist, Pittsburgh, PA), and extracorporeal membrane oxygenation, are more accessible. Compared with intra-aortic balloon pump, Impella provides greater hemodynamic support but no reduction in mortality. Similarly, TandemHeart improves hemodynamic variables but not survival. Comparative studies have been underpowered for mortality because of small sample size. Veno-arterial extracorporeal membrane oxygenation offers the advantage of biventricular circulatory support and oxygenation, but there are significant vascular complications. Comparative studies with extracorporeal membrane oxygenation have not been completed. Despite lack of randomized controlled data, there has been a substantial increase in use of percutaneous mechanical circulatory support. Several ongoing prospective studies with larger sample sizes may provide answers, and newer devices may become smaller, easier to insert, and more effective.

CONCLUSIONS

Mortality from cardiogenic shock remains unacceptably high despite early coronary revascularization or other therapies. Although evidence is lacking and complications rates are high, improvements and experience with percutaneous mechanical circulatory support may offer the prospect of better outcomes.