Extracorporeal Membrane Oxygenation for Bridge to Heart Transplantation Among Children in the United States

Short-Term Mortality Among Pediatric Patients With Heart Diseases Undergoing Veno-Arterial Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation serves as a crucial mechanical circulatory support for pediatric patients with severe heart diseases, but the mortality rate remains high. The objective of this study was to assess the short-term mortality in these patients.

METHODS AND RESULTS

We systematically searched PubMed, Embase, and Cochrane Library for observational studies that evaluated the short-term mortality of pediatric patients undergoing veno-arterial extracorporeal membrane oxygenation. To estimate short-term mortality, we used random-effects meta-analysis. Furthermore, we conducted meta-regression and binomial regression analyses to investigate the risk factors associated with the outcome of interest. We systematically reviewed 28 eligible references encompassing a total of 1736 patients. The pooled analysis demonstrated a short-term mortality (defined as in-hospital or 30-day mortality) of 45.6% (95% CI, 38.7%-52.4%). We found a significant difference (P<0.001) in mortality rates between acute fulminant myocarditis and congenital heart disease, with acute fulminant myocarditis exhibiting a lower mortality rate. Our findings revealed a negative correlation between older age and weight and short-term mortality in patients undergoing veno-arterial extracorporeal membrane oxygenation. Male sex, bleeding, renal damage, and central cannulation were associated with an increased risk of short-term mortality.

CONCLUSIONS

The short-term mortality among pediatric patients undergoing veno-arterial extracorporeal membrane oxygenation for severe heart diseases was 45.6%. Patients with acute fulminant myocarditis exhibited more favorable survival rates compared with those with congenital heart disease. Several risk factors, including male sex, bleeding, renal damage, and central cannulation contributed to an increased risk of short-term mortality. Conversely, older age and greater weight appeared to be protective factors.

Optimizing Outcomes in Extracorporeal Membrane Oxygenation Postcardiotomy in Pediatric Population

Extracorporeal membrane oxygenation (ECMO) is a rapidly emerging advanced life support technique used in cardiorespiratory failure refractory to other treatments. There has been an influx in the number of studies relating to ECMO in recent years, as the technique becomes more popular. However, there are still significant gaps in the literature including complications and their impacts and methods to predict their development. This review evaluates the available literature on the complications of ECMO postcardiotomy in the pediatric population. Areas explored include renal, cardiovascular, hematological, infection, neurological, and hepatic complications. Incidence, risk factors and potential predictors, and scoring systems for the development of these complications have been evaluated.

Treatment Strategies for Cardiomyopathy in Children: A Scientific Statement From the American Heart Association

This scientific statement from the American Heart Association focuses on treatment strategies and modalities for cardiomyopathy (heart muscle disease) in children and serves as a companion scientific statement for the recent statement on the classification and diagnosis of cardiomyopathy in children. We propose that the foundation of treatment of pediatric cardiomyopathies is based on these principles applied as personalized therapy for children with cardiomyopathy: (1) identification of the specific cardiac pathophysiology; (2) determination of the root cause of the cardiomyopathy so that, if applicable, cause-specific treatment can occur (precision medicine); and (3) application of therapies based on the associated clinical milieu of the patient. These clinical milieus include patients at risk for developing cardiomyopathy (cardiomyopathy phenotype negative), asymptomatic patients with cardiomyopathy (phenotype positive), patients with symptomatic cardiomyopathy, and patients with end-stage cardiomyopathy. This scientific statement focuses primarily on the most frequent phenotypes, dilated and hypertrophic, that occur in children. Other less frequent cardiomyopathies, including left ventricular noncompaction, restrictive cardiomyopathy, and arrhythmogenic cardiomyopathy, are discussed in less detail. Suggestions are based on previous clinical and investigational experience, extrapolating therapies for cardiomyopathies in adults to children and noting the problems and challenges that have arisen in this experience. These likely underscore the increasingly apparent differences in pathogenesis and even pathophysiology in childhood cardiomyopathies compared with adult disease. These differences will likely affect the utility of some adult therapy strategies. Therefore, special emphasis has been placed on cause-specific therapies in children for prevention and attenuation of their cardiomyopathy in addition to symptomatic treatments. Current investigational strategies and treatments not in wide clinical practice, including future direction for investigational management strategies, trial designs, and collaborative networks, are also discussed because they have the potential to further refine and improve the health and outcomes of children with cardiomyopathy in the future.

Failing Fontan cardiovascular support: Review

BACKGROUND

Although all congenital heart defects (CHD) present unique challenges, univentricular CHD are especially challenging given the difficulty of passively perfusing pulmonary blood flow. Three surgical procedures are required within the first years of life, with the final completing a Fontan circulation in which the inferior vena cava is connected to the pulmonary artery and previously connected superior vena cava. This allows passive venous return to the pulmonary circulation then flow into the single ventricle for systemic circulation.

METHODS

Although a Fontan provides successful palliation for two to three decades, many complications can arise as pulmonary resistance must remain low to allow adequate forward flow. Eventually, the failing Fontan circulation requires temporary support as the patient awaits a heart transplant. We reviewed PubMed, Google Scholar, and U. Kentucky library for different techniques evaluated to support a failing Fontan circulation.

RESULTS

Multiple technologies have been developed as a bridge to transplant to decrease morbidity. Innovative types of extracorporeal membrane oxygenation, ventricular assist devices, and total artificial hearts have been attempted in laboratory settings as well as in Fontan patients with varying degrees of success. This article emphasizes the strengths and weaknesses of each technology in the context of Fontan physiology.

CONCLUSION

The end game for these patients remains a heart transplant. Without easy access to donors, each of the options discussed is a potential bridge to limit morbidity and mortality until a suitable donor heart becomes available.

Development of a Model for the Pediatric Survival After Veno-Arterial Extracorporeal Membrane Oxygenation Score: The Pedi-SAVE Score

Pediatric cardiac extracorporeal membrane oxygenation (ECMO) patients have high mortality rates. The purpose of our study was to develop and validate the Pediatric Survival After Veno-arterial ECMO (Pedi-SAVE) score for predicting survival at hospital discharge after pediatric cardiac veno-arterial (VA) ECMO. We used data for pediatric cardiac VA-ECMO patients from the Extracorporeal Life Support Organization registry (1/1/2001-12/31/2015). Development and validation cohorts were created using 2:1 random sampling. Predictors of survival to develop pre- and postcannulation models were selected using multivariable logistic regression and random forest models. ß-coefficients were standardized to create the Pedi-SAVE score. Of 10,091 pediatric cardiac VA-ECMO patients, 4,996 (50%) survived to hospital discharge. Pre- and postcannulation Pedi-SAVE scores predicted that the lowest risk patients have a 65% and 74% chance of survival at hospital discharge, respectively, compared to 33% and 22% in the highest risk patients. In the validation cohort, pre- and postcannulation Pedi-SAVE scores had c-statistics of 0.64 and 0.71, respectively. Precannulation factors associated with survival included: nonsingle ventricle congenital heart disease, older age, white race, lower STAT mortality category, higher pH, not requiring acid-buffer administration, <2 cardiac procedures, and indication for VA-ECMO other than failure to wean from cardiopulmonary bypass. Postcannulation, additional factors associated with survival included: lower ECMO pump flows at 24 hours and lack of complications. The Pedi-SAVE score is a novel validated tool to predict survival at hospital discharge for pediatric cardiac VA-ECMO patients, and is an important advancement in risk adjustment and benchmarking for this population.

Pediatric heart transplantation: The past, the present, and the future

Heart transplantation (HTx) has a storied past, with origins dating back to the early twentieth century and the first pediatric orthotopic heart transplant performed in 1967 on a neonate with Ebstein abnormality. Today, approximately 500 pediatric HTx are performed annually, with survival times now measured in decades rather than days or weeks. In large part, advances in immunosuppression, critical care, dedicated transplant teams and mechanical circulatory support have paved the way for improvements in waitlist mortality and post-transplant survival, with future directions including the development of intracorporeal ventricular assist devices (VADs) for small children, expanding/standardizing donor criteria, and xenotransplantation.

Extracorporeal membrane oxygenation in children: An update of a single tertiary center 11-Year experience from Croatia

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is an important treatment option for organ support in respiratory insufficiency, cardiac failure, or as an advanced tool for cardiopulmonary resuscitation. Reports on pediatric ECMO use in our region are lacking.

METHODS

This study is a retrospective review of all pediatric cases that underwent a veno-arterial (VA) or veno-venous (VV) ECMO protocol between November 2009 and August 2020 at the Department of Pediatrics, University Hospital Center Zagreb, Croatia.

RESULTS

Fifty-two ECMO runs identified over the period; data were complete for 45 cases, of which 23 (51%) were female, and median age was 8 months. Thirty-eight (84%) patients were treated using the VA-and 7 (16%) using VV-ECMO. The overall survival rate was 51%. Circulatory failure was the most common indication for ECMO (N = 38, 84%), and in 17 patients ECMO was started after cardiopulmonary resuscitation (E-CPR). Among survivors, 74% had no or minor neurological sequelae. Variables associated with poor outcome were renal failure with renal replacement therapy (p < .001) and intracranial injury (p < .001).

CONCLUSION

Overall survival rate in our cohort is comparable to the data published in the literature. The use of hemodialysis was shown to be associated with higher mortality. High rates of full neurological recovery among survivors are a strong case for further ECMO program development in our institution.

Models of Shear-Induced Platelet Activation and Numerical Implementation With Computational Fluid Dynamics Approaches

Shear-induced platelet activation is one of the critical outcomes when blood is exposed to elevated shear stress. Excessively activated platelets in the circulation can lead to thrombus formation and platelet consumption, resulting in serious adverse events such as thromboembolism and bleeding. While experimental observations reveal that it is related to the shear stress level and exposure time, the underlying mechanism of shear-induced platelet activation is not fully understood. Various models have been proposed to relate shear stress levels to platelet activation, yet most are modified from the empirically calibrated power-law model. Newly developed multiscale platelet models are tested as a promising approach to capture a single platelet's dynamic shape during activation, but it would be computationally expensive to employ it for a large-scale analysis. This paper summarizes the current numerical models used to study the shear-induced platelet activation and their computational applications in the risk assessment of a particular flow pattern and clot formation prediction.

Support with extracorporeal membrane oxygenation for over 1 year duration as a bridge to cardiac transplantation: a case report and review of the literature

We present the case of a 13-year-old male with a complex congenital cardiac history who was supported with extracorporeal membrane oxygenation for 394 days while awaiting cardiac transplantation. The patient underwent successful cardiac transplantation after 394 days of support with veno-arterial extracorporeal membrane oxygenation and is currently alive 2 years after cardiac transplantation. We believe that this case represents the longest period of time that a patient has been supported with extracorporeal membrane oxygenation as a bridge to cardiac transplantation.We also review the literature associated with prolonged support with extracorporeal membrane oxygenation. This case report documents many of the challenges associated with prolonged support with extracorporeal membrane oxygenation, including polymicrobial bacterial and fungal infections, as well as renal dysfunction. It is possible to successfully bridge a patient to cardiac transplantation with prolonged support with extracorporeal membrane oxygenation of over 1 year; however, multidisciplinary collaboration is critical.

Rehabilitation in Pediatric Heart Failure and Heart Transplant

Survival of pediatric patients with heart failure has improved due to medical and surgical advances over the past decades. The complexity of pediatric heart transplant patients has increased as medical and surgical management for patients with congenital heart disease continues to improve. Quality of life in patients with heart failure and transplant might be affected by the impact on functional status that heart failure, heart failure complications or treatment might have. Functional areas affected might be motor, exercise capacity, feeding, speech and/or cognition. The goal of rehabilitation is to enhance and restore functional ability and quality of life to those with physical impairments or disabilities. Some of these rehabilitation interventions such as exercise training have been extensively evaluated in adults with heart failure. Literature in the pediatric population is limited yet promising. The use of additional rehabilitation interventions geared toward specific complications experienced by patients with heart failure or heart transplant are potentially helpful. The use of individualized multidisciplinary rehabilitation program that includes medical management, rehabilitation equipment and the use of physical, occupational, speech and feeding therapies can help improve the quality of life of patients with heart failure and transplant.

Extracorporeal Life Support Organization (ELSO): Guidelines for Pediatric Cardiac Failure

These guidelines are applicable to neonates and children with cardiac failure as indication for extracorporeal life support. These guidelines address patient selection, management during extracorporeal membrane oxygenation, and pathways for weaning support or bridging to other therapies. Equally important issues, such as personnel, training, credentialing, resources, follow-up, reporting, and quality assurance, are addressed in other Extracorporeal Life Support Organization documents or are center-specific.

The role of extracorporeal membrane oxygenation in pediatric abdominal transplant patients: A qualitative systematic review of literature

BACKGROUND

Advances in ECMO have made it a useful adjunct in critically ill pediatric patients; however, a dearth of evidence exists regarding risks and benefits in pediatric abdominal transplantation. The purpose of this study was to perform a qualitative systematic review of outcomes in pediatric patients undergoing ECMO support pre- or post-abdominal organ transplantation.

METHODS

This was a systematic review conducted from Jan 1, 1989, to April 24, 2020, via PubMed, Embase, Scopus, Web of Science, the Cochrane Library, and ClinicalTrials.gov of all pediatric solid abdominal organ transplant recipients (pre- and post-transplant) and donors who underwent V-A or V-V ECMO cannulation. Death was the primary outcome, with graft function and complications as secondary outcomes.

RESULTS

Fourteen articles were identified that fit criteria, with 88% being case reports. Three patients were donors placed on ECMO, with no mortality among the 8 recipients of organs from these donors. Nineteen recipients were placed on ECMO. All were liver transplants. Most patients experienced at least one complication (84%), with bleeding as the most common cause (44%). Mortality was 26%. Causes of death included multiorgan system failure (n = 3), heart failure (n = 1), Systemic inflammatory response syndrome (n = 1), abdominal compartment syndrome (n = 3), bleeding (n = 1), septic shock from aspergillus (n = 1), and hepatic artery thrombosis (n = 2).

CONCLUSIONS

The data are poor on ECMO usage in pediatric abdominal transplantation. While complications were high, mortality did not appear to be related to ECMO usage and was relatively low given the severity of patient illness.

Use of ECMO for Cardiogenic Shock in Pediatric Population

In children with severe advanced heart failure where medical management has failed, mechanical circulatory support in the form of veno-arterial extracorporeal membrane oxygenation (VA ECMO) or ventricular assist device represents life-sustaining therapy. This review provides an overview of VA ECMO used for cardiovascular support including medical and surgical heart disease. Indications, contraindications, and outcomes of VA ECMO in the pediatric population are discussed.VA ECMO provides biventricular and respiratory support and can be deployed in rapid fashion to rescue patient with failing physiology. There have been advances in conduct and technologic aspects of VA ECMO, but survival outcomes have not improved. Stringent selection and optimal timing of deployment are critical to improve mortality and morbidity of the patients supported with VA ECMO.

Neurologic complications of pediatric congenital heart disease

Improved medical management and surgical outcomes have significantly decreased mortality in children with congenital heart disease; however, with increased survival, there is a greater lifetime exposure to neurologic complications with serious long-term neurodevelopmental consequences. Thus, recent focus has shifted to recognition and reduction of these extracardiac comorbidities. Vascular and infective complications, such as arterial ischemic stroke, infective endocarditis, and localization-related epilepsy are some of the most common neurologic comorbidities of congenital heart disease. In addition, it is now well recognized that congenital heart disease has an impact on overall brain development and contributes to adverse neurodevelopmental outcomes across multiple domains. The goal of this chapter is to summarize the most common neurologic comorbidities of congenital heart disease and its management.

Pathophysiology and molecular signalling in pediatric heart failure and VAD therapy

Heart Failure (HF) is a progressive clinical syndrome characterized by molecular and structural abnormalities that result in impaired ventricular filling and a reduced blood ejection. In pediatric patients, HF represents an important cause of morbidity and mortality, but underlying cause, presentation and disease course remains unclear in many cases. It is evident that a child is not a "small adult" and findings are not comparable. The adoption of a standardized clinical and surgical tools as well as increased biomolecular research and therapeutic trials targeting pediatric patients with HF would greatly improve the management of this special class of patients. This review examines the most current information about the pathophysiology and molecular mechanisms related to HF in children to identify gaps in our knowledge base to further improve clinical care and outcomes.

End-Stage Liver Disease Models and Outcomes in Pediatric Patients Supported With Short-Term Continuous-Flow Ventricular Assist Devices

Short-term continuous-flow ventricular assist devices (STCF-VADs) are increasingly being utilized in pediatrics. End-stage liver disease (ELD) models have been associated with outcomes in adult patients on mechanical circulatory support. We sought to determine the relationship between outcomes in children on STCF-VADs and three ELD models: model for end-stage liver disease-excluding international normalized ratio (MELD-XI; all) and MELD-XI (> 1 year), PELD, and a novel score, PedMELD-XI. All patients (< 19 years) supported with STCF-VADs, between June 2009 and December 2016 were included. The MELD-XI, PELD, and PedMELD-XI scores were calculated and their association with adverse events and a composite measure of death, major bleeding, and neurologic dysfunction was analyzed. Of 32 patients, median age was 0.57 years (interquartile range [IQR], 0.10-4.43), median weight was 7.15 kg (IQR, 3.68-16.53), 53.1% had congenital heart disease, and 53.1% were male. In total, 78.1% patients experienced an adverse event (78.1% a major bleed, 25.0% neurologic dysfunction, and 15.6% death). The median MELD-XI score was 11.17 (IQR, 9.44-30.01), MELD-XI (>1 year) 9.44 (IQR, 9.44-24.33), PELD 6.00 (IQR, 4.00-13.75), and PedMELD-XI -14.91 (IQR, -18.85 to -12.25). A higher MELD-XI for all ages (13.80 vs. 9.44, p = 0.037) and less negative PedMELD-XI (-14.16 vs. -19.34, p = 0.028) scores were significantly associated with bleeding and the composite outcome. PedMELD-XI was significantly associated with death (-12.87 vs. -16.84, p = 0.041) while a trend was seen for increased MELD-XI in all ages being associated with death (31.52 vs. 10.11, p = 0.051). Last, there was no association with the models and neurologic events. MELD-XI and PedMELD-XI were significantly associated with major bleeding and the composite endpoints with PedMELD-XI also being associated with death. These results suggest that ELD models can be used to predict outcomes in this specific patient population, however, further analysis in a larger population is required.

Outcomes of Pediatric Patients Treated With Extracorporeal Membrane Oxygenation for Intractable Supraventricular Arrhythmias

OBJECTIVES

Extracorporeal membrane oxygenation is used to support refractory cardiorespiratory failure. Outcomes and complications when extracorporeal membrane oxygenation is used to support cardiorespiratory failure secondary to arrhythmia in pediatric patients remain poorly defined. Our purpose is to describe pediatric patients requiring extracorporeal membrane oxygenation support for supraventricular arrhythmias in the context of normal cardiac anatomy and congenital heart disease and identify patient/peri-extracorporeal membrane oxygenation variables associated with extracorporeal membrane oxygenation-related complications and survival.

DESIGN

Retrospective multicenter review from 1993 to 2016.

SETTING

Extracorporeal Life Support Organization registry.

SUBJECTS

Patients younger than 21 years old requiring extracorporeal membrane oxygenation support for supraventricular arrhythmias.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 342 patients were identified (weight, 3.8 kg [3.2-7.5 kg]; age at extracorporeal membrane oxygenation initiation, 24 d [6-222]; 61% male). Sixty-five percentage survived to hospital discharge. Complications were frequent (85%) and most commonly cardiac related (31%). In multivariable modeling, mortality was associated with congenital heart disease, time from intubation to extracorporeal membrane oxygenation initiation, use of bicarbonate prior to extracorporeal membrane oxygenation, extracorporeal membrane oxygenation duration, and the presence of a complication. The presence of any complication was associated with a three-fold increase in the odds of death. In subgroup analysis of isolated supraventricular arrhythmias patients, similar patient and extracorporeal membrane oxygenation characteristics were associated with outcome. A lower pre-extracorporeal membrane oxygenation pH and PCO2 and site of venous cannulation were associated with complications (p < 0.02).

CONCLUSIONS

Extracorporeal membrane oxygenation use for medically refractory supraventricular arrhythmias was associated with a 65% survival to hospital discharge. However, there was a high rate of complications, the presence of which was associated with decreased survival. Complications appeared to be related to pre-extracorporeal membrane oxygenation clinical status and whether earlier extracorporeal membrane oxygenation cannulation prior to patient deterioration would improve outcomes needs additional evaluation.

Highlights from the Extracorporeal Life Support Organization Registry: 2006-2017

Extracorporeal membrane oxygenation (ECMO) is a supportive therapy for patients with severe cardiovascular or respiratory failure refractory to conventional medical therapy. Improvements in ECMO technology, easy access to ECMO devices, and a greater understanding of care of ECMO patients have led to increased utilization of ECMO. The Extracorporeal Life Support Organization (ELSO) registry was established in 1984, to collect data on patients receiving ECMO support to help improve outcomes of these patients. The registry has grown to include over 400 contributing centers from 60 countries with data for more than 90,000 patients. Many investigators have used the ELSO registry to answer clinical questions on outcomes and care of this vulnerable patient population. This report provides a brief summary of 16 peer-reviewed articles that have advanced the knowledge and treatment of neonates, children, and adults supported with ECMO using data from the ELSO registry.

Long-term survival and costs following extracorporeal membrane oxygenation in critically ill children-a population-based cohort study

Background

Extracorporeal membrane oxygenation (ECMO) is used to provide temporary cardiorespiratory support to critically ill children. While short-term outcomes and costs have been evaluated in this population, less is known regarding long-term survival and costs.

Methods

Population-based cohort study from Ontario, Canada (October 1, 2009 to March 31, 2017), of pediatric patients (< 18 years of age) receiving ECMO, identified through the use of an ECMO procedural code. Outcomes were identified through linkage to provincial health databases. Primary outcome was survival, measured to hospital discharge, as well as at 1 year, 2 years, and 5 years following ECMO initiation. We evaluated total patient costs in the first year following ECMO.

Results

We analyzed 342 pediatric patients. Mean age at ECMO initiation was 2.9 years (standard deviation [SD] = 5.0). Median time from hospital admission to ECMO initiation was 5 days (interquartile range [IQR] = 1–13 days). Overall survival to hospital discharge was 56.4%. Survival at 1 year, 2 years, and 5 years was 51.5%, 50.0%, and 42.1%, respectively. Among survivors, 99.5% were discharged home. Median total costs among all patients in the year following hospital admission were $147,957 (IQR $70,571–$300,295). Of these costs, the large proportion were attributable to the inpatient cost from the index admission (median $119,197, IQR $57,839–$250,675).

Conclusions

Children requiring ECMO continue to have a significant in-hospital mortality, but reassuringly, there is little decrease in long-term survival at 1 year. Median costs among all patients were substantial, but largely reflect inpatient hospital costs, rather than post-discharge outpatient costs. This information provides value to providers and health systems, allowing for prognostication of short- and long-term outcomes, as well as long-term healthcare-related expenses for pediatric ECMO survivors.

Review on Mechanical Support and Cell-Based Therapies for the Prevention and Recovery of the Failed Fontan-Kreutzer Circulation

Though the current staged surgical strategy for palliation of single ventricle heart disease, culminating in a Fontan circulation, has increased short-term survival, mounting evidence has shown that the single ventricle, especially a morphologic right ventricle (RV), is inadequate for long-term circulatory support. In addition to high rates of ventricular failure, high central venous pressures (CVP) lead to liver fibrosis or cirrhosis, lymphatic dysfunction, kidney failure, and other comorbidities. In this review, we discuss the complications seen with Fontan physiology, including causes of ventricular and multi-organ failure. We then evaluate the clinical use, results, and limitations of long-term mechanical assist devices intended to reduce RV work and high CVP, as well as biological therapies for failed Fontan circulations. Finally, we discuss experimental tissue engineering solutions designed to prevent Fontan circulation failure and evaluate knowledge gaps and needed technology development to realize a more robust single ventricle therapy.

Developments in Pediatric Ventricular Assist Device Support

Mechanical support devices have revolutionized the management of circulatory failure. This has been met by a dramatic increase in ventricular assist device (VAD) utilization in children over the last two decades. Previous wide gaps in experience and knowledge have significantly narrowed in the recent years. As we continue to gain experience with this technology, we face new challenges such as complex congenital circulations and small patient size. The emergence of new pharmacologic therapies and device technology offers more opportunities and requires constant adjustment in practice. As we continue to embark on this journey, constant insight is needed to refine patient selection criteria, minimize complications, and continue to push the field for safer smaller devices to accommodate these complex patient populations. In this review focused at inpatient critical care environment, we discuss the recent field developments and focus on challenging patient populations, the emergence of temporary support, management of anticoagulation, and diagnostic approach to stroke in the setting of VAD support.

Structured review of post-cardiotomy extracorporeal membrane oxygenation: Part 2-pediatric patients

Veno-arterial extracorporeal membrane oxygenation (ECMO) is established therapy for short-term circulatory support for children with life-treating cardiorespiratory dysfunction. In children with congenital heart disease (CHD), ECMO is commonly used to support patients with post-cardiotomy shock or complications including intractable arrhythmias, cardiac arrest, and acute respiratory failure. Cannulation configurations include central, when the right atrium and aorta are utilized in patients with recent sternotomy, or peripheral, when cannulation of the neck or femoral vessels are used in non-operative patients. ECMO can be used to support any form of cardiac disease, including univentricular palliated circulation. Although veno-arterial ECMO is commonly used to support children with CHD, veno-venous ECMO has been used in selected patients with hypoxemia or ventilatory failure in the presence of good cardiac function. ECMO use and outcomes in the CHD population are mainly informed by single-center studies and reports from collated registry data. Significant knowledge gaps remain, including optimal patient selection, timing of ECMO deployment, duration of support, anti-coagulation, complications, and the impact of these factors on short- and long-term outcomes. This report, therefore, aims to present a comprehensive overview of the available literature informing patient selection, ECMO management, and in-hospital and early post-discharge outcomes in pediatric patients treated with ECMO for post-cardiotomy cardiorespiratory failure.

Pediatric Acute Myocarditis: Predicting Hemodynamic Compromise at Presentation to Health Care

BACKGROUND

The clinical spectrum of pediatric acute myocarditis ranges from minimal symptoms with intact hemodynamics to rapid cardiovascular collapse and death. We sought to identify factors on initial presentation associated with subsequent hemodynamic compromise.

METHODS

We performed a retrospective cohort study of patients with acute myocarditis at a freestanding pediatric hospital from 2007 to 2016. We defined 2 cohorts: high-acuity patients with hemodynamic compromise defined as requiring inotropic or vasoactive medications, cardiopulmonary resuscitation, extracorporeal membrane oxygenation, ventricular assist devices, or transplant or who died and low-acuity patients without these interventions. We collected the first recorded set of vital signs, symptoms, laboratory values, and chest radiograph, electrocardiogram, and echocardiography results. Univariate analysis was performed, and 2 multivariable logistic regression models were created to discriminate between cohorts.

RESULTS

A total of 74 patients were included: 33 high acuity and 41 low acuity. There were significant differences in demographics, symptoms, and physical examination, laboratory, electrocardiogram, and echocardiography findings between high- and low-acuity cohorts. Multivariable logistic regression models were highly discriminate in predicting those in the high-acuity cohort. The first model included presence of tachycardia, tachypnea, creatinine, and cardiomegaly on chest radiograph (area under the curve = 0.913). The second model added the presence of pericardial effusion to the above variables (area under the curve = 0.964).

CONCLUSIONS

Models based on factors available at initial presentation with acute myocarditis are predictive of subsequent hemodynamic compromise. If our results can be validated in a multicenter study, these models may help disposition patients with suspected acute myocarditis (with those who meet model criteria being admitted to centers capable of rapidly providing extracorporeal membrane oxygenation, ventricular assist devices, and heart transplant evaluation).

The Extracorporeal Life Support Organization Registry: update and perspectives

From the birth of the Extracorporeal Life Support Organization (ELSO) Registry in 1989, collecting the most relevant information about extracorporeal life support (ECLS) for refractory cardiac or respiratory compromise, was created in order to provide useful information and benchmark for ECLS users. Throughout the years, the Registry has continuously developed, achieving in 2018 more than 100,000 patients included with almost 500 ELSO centers around the world. Based on the relevance and impact of database analysis, and due to the growing need for more advanced and high-quality clinical investigations, the ELSO Registry is under substantial re-engineering which will allow and provide the ELSO members and the scientific community an enhanced scientific tool to elucidate various aspects of the ECLS settings, including trends and disease-specific information, to perform benchmarking about our own results and outcomes as compared to regional or worldwide results, and to provide an invaluable source of data for clinical investigations.

Extracorporeal membrane oxygenation, Berlin, and ventricular assist devices: a primer for the cardiologist

PURPOSE OF REVIEW

Mechanical circulatory support (MCS) has become an indispensable tool in the management of children with impending respiratory and cardiac failure. Though extracorporeal membrane oxygenation (ECMO) was classically the only form of support available to pediatric patients, considerable advances have allowed ventricular assist devices (VADs) to become increasingly utilized in children. This review provides an update of recent advances in ECMO and VAD management in children.

RECENT FINDINGS

The options for mechanical support in infants and small children with end-stage heart failure are limited. As such, the greatest advances in the past decade have come in the successful adoption of the Berlin Heart EXCOR device, with a marked improvement in survival to transplant over ECMO. Further advances have been made in the use of adult VADs in children. For instance, the HeartWare HVAD has been utilized in children as young as 3 years of age, despite being designed for use in adult patients.

SUMMARY

The availability of mechanical support options for children remains limited to ECMO and a small number of VADs. While outcomes of VAD support in pediatric patients have been promising, further study in smaller and more complex pediatric patients is necessary.

Comparison of Transplant Waitlist Outcomes for Pediatric Candidates Supported by Ventricular Assist Devices Versus Medical Therapy

OBJECTIVES

Ventricular assist devices have gained popularity in the management of refractory heart failure in children listed for heart transplantation. Our primary aim was to compare the composite endpoint of all-cause pretransplant mortality and loss of transplant eligibility in children who were treated with a ventricular assist device versus a medically managed cohort.

DESIGN

This was a retrospective cohort analysis.

SETTINGS

Data were obtained from the Scientific Registry of Transplant Recipients.

PATIENTS

The at-risk population (n = 1,380) was less than 18 years old, either on a ventricular assist device (605 cases) or an equivalent-severity, intensively medically treated group (referred to as MED, 775 cases).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The impact of ventricular assist devices was estimated via Cox proportional hazards regression (hazard ratio), dichotomizing 1-year outcomes to "poor" (22%: 193 deaths, 114 too sick) versus all others (940 successful transplants, 41 too healthy, 90 censored), while adjusting for conventional risk factors. Among children 0-12 months old, ventricular assist device was associated with a higher risk of poor outcomes (hazard ratio, 2.1; 95% CI, 1.5-3.0; p < 0.001). By contrast, ventricular assist device was associated with improved outcomes for ages 12-18 (hazard ratio, 0.3; 95% CI, 0.1-0.7; p = 0.003). For candidates 1-5 and 6-11 years old, there were no differences in outcomes between the ventricular assist device and MED groups (hazard ratio, 0.8 and 1.0, p = 0.43 and 0.9). The interaction between ventricular assist devices and age group was strongly significant (p < 0.001).

CONCLUSIONS

This is a comparative study of ventricular assist devices versus medical therapy in children. Age is a significant modulator of waitlist outcomes for children with end-stage heart failure supported by ventricular assist device, with the impact of ventricular assist devices being more beneficial in adolescents.

An overview of mechanical circulatory support in single-ventricle patients

The population of people with a single-ventricle is continually increasing due to improvements across the spectrum of medical care. Unfortunately, a proportion of these patients will develop heart failure. Often, for these patients, mechanical circulatory support (MCS) represents the only available treatment option. While single-ventricle patients currently represent a small proportion of the total number of patients who receive MCS, as the single-ventricle patient population increases, this number will increase as well. Outcomes for these complex single-ventricle patients who require MCS has begun to be evaluated. When considering the entire population, survival to hospital discharge is 30-50%, though this must be considered with the significant heterogeneity of the single-ventricle patient population. Patients with a single-ventricle have unique anatomy, mechanisms of failure, indications for MCS and the type of support utilized. This has made the interpretation and the generalizability of the limited available data difficult. It is likely that some subsets will have a significantly worse prognosis and others a better one. Unfortunately, with these limited data, indications of a favorable or poor outcome have not yet been elucidated. Though currently, a database has been constructed to address this issue. While the outcomes for these complex patients is unclear, at least in some situations, they are poor. However, significant advances may provide improvements going forward, including new devices, computer simulations and 3D printed models. The most important factor, however, will be the increased experience gained by the heart failure team to improve patient selection, timing, device and configuration selection and operative approach.

Prelisting predictions of early postoperative survival in infant heart transplantation using classification and regression tree analysis

Infants listed for heart transplantation experience high waitlist and early post-transplant mortality, and thus, optimal allocation of scarce donor organs is required. Unfortunately, the creation and validation of multivariable regression models to identify risk factors and generate individual-level predictions are challenging. We sought to explore the use of data mining methods to generate a prediction model. CART analysis was used to create a model which, at the time of listing, would predict which infants listed for heart transplantation would survive at least 3 months post-transplantation. A total of 48 infants were included; 13 died while waiting, and six died within 3 months of heart transplant. CART analysis identified RRT, blood urea nitrogen, and hematocrit as terminal nodes with alanine transaminase as an intermediate node predicting death. No patients listed on RRT (n = 10) survived and only three of 12 (25%) patients listed on ECLS survived >3 months post-transplant. CART analysis overall accuracy was 83%, with sensitivity of 95% and specificity 76%. This study shows that CART analysis can be used to generate accurate prediction models in small patient populations. Model validation will be necessary before incorporation into decision-making algorithms used to determine transplant candidacy.

Extracorporeal membrane oxygenation in congenital heart disease

This review article will discuss the indications for and outcomes of neonates with congenital heart disease who receive extracorporeal membrane oxygenation (ECMO) support. Most commonly, ECMO is used as a perioperative bridge to recovery or temporary support for those after cardiac arrest or near arrest in patients with congenital or acquired heart disease. What had historically been considered a contraindication to ECMO, is evolving and more of the sickest and most complicated babies are cared for on ECMO. Given that, it is imperative for aggressive survellience for long-term morbidity in survivors, particularly neurodevelopmental outcomes.

Identifiable Risk Factors and Miscalculations During Listing for Pediatric Heart Transplantation

The objective of this study is to describe identifiable risk factors, complications, and pitfalls while listing pediatric patients for heart transplantation, which is the standard of care for end-stage heart disease in children. Since the introduction of cyclosporine in the 1980s, the management in pediatric heart transplantation has shown consistent improvement, mainly because of technological advances and the integration of multidisciplinary teams in the field. However, the complexity of this patient population makes medical providers vulnerable to complications as a result of undesirable mistakes. Transplant survival is impacted negatively when mistakes from health-care providers compound the high-risk status of the patient. The identification of multiple risk factors and undesirable miscalculations may help transplant teams make decisions before allocating organs, intervene or minimize morbidity, and provide the best quality of life to recipients.

Multicenter Experience With Mechanical Circulatory Support Using a New Diagonal Pump in 233 Children

Technological innovations in pediatric extracorporeal life support circuits can reduce system-related complications and may improve patients' outcome. The Deltastream DP3 (Medos Medizintechnik AG, Stolberg, Germany) is a novel rotational pump with a diagonally streamed impeller that can be used over a broad range of flows. We collected patient data from seven pediatric centers to conduct a retrospective cohort study. We examined 233 patients whose median age was 1.9 (0-201) months. The DP3 system was used for cardiopulmonary support as veno-arterial extracorporeal membrane oxygenation (ECMO) in 162 patients. Respiratory support via veno-venous ECMO was provided in 63 patients. The pump was used as a ventricular assist device in eight patients. Median supporting time was 5.5 (0.2-69) days and the weaning rate was 72.5%. The discharge home rate was 62% in the pulmonary group versus 55% in the cardiac group. Extracorporeal cardiopulmonary resuscitation was carried out in 24 patients (10%) with a survival to discharge of rate of 37.5%. About 106 (47%) children experienced no complications, while 33% suffered bleeding requiring blood transfusion or surgical intervention. Three patients suffered a fatal cerebral event. Renal replacement therapy was performed in 28% and pump or oxygenator exchange in 26%. Multivariable analysis identified system exchange (OR 1.94), kidney failure (OR 3.43), and complications on support (OR 2.56) as risk factors for dismal outcome. This novel diagonal pump has demonstrated its efficacy in all kinds of mechanical circulatory and respiratory support, revealing good survival rates.

Outcomes of Extracorporeal Membrane Oxygenation in Children: An 11-Year Single-Center Experience in Korea

Background

Extracorporeal membrane oxygenation (ECMO) has become an important treatment modality in pediatric patients with cardiopulmonary failure, but few studies have been conducted in Korea.

Methods

We conducted a retrospective review of pediatric patients younger than 18 years who were placed on ECMO between January 2004 and December 2014 at Samsung Medical Center.

Results

We identified 116 children on ECMO support. The overall rate of successful weaning was 51.7%, and the survival to discharge rate was 37.1%. There were 39, 61, and 16 patients on ECMO for respiratory, cardiac, and extracorporeal cardiopulmonary resuscitation, respectively. The weaning rate in each group was 48.7%, 55.7%, and 43.8%, respectively. The survival rate was 43.6%, 36.1%, and 25.0%, respectively. Sixteen patients on ECMO had functional single ventricle physiology; in this group, the weaning rate was 43.8% and the survival rate was 31.3%. Ten patients were on ECMO as a bridge to transplantation (8 for heart and 2 for lung). In patients with heart transplantation, the rate of survival to transplantation was 50.0%, and the overall rate of survival to discharge was 37.5%.

Conclusion

An increasing trend in pediatric ECMO utilization was observed. The outcomes were favorable considering the early experiences that were included in this study and the limited supply of specialized equipment for pediatric patients.

Cost-utility analysis of direct ventricular assist device vs double bridges to heart transplantation in patients with refractory heart failure

OBJECT

This study compared the cost-utility of direct ventricular assist device (VAD) vs double bridges, extracorporeal membrane oxygenation (ECMO) before VAD, to heart transplantation in patients with refractory heart failure.

MATERIALS AND METHODS

From a health payer perspective, a Markov model was developed. The cycle length was 1 month, and the time horizon was a lifetime. Probabilities and direct cost data were calculated from a nationwide claim database. Utility inputs were adopted from published sources. The utility was expressed as quality-adjusted life years (QALYs). Both costs and utility were discounted by an annual rate of 3%. Deterministic and probabilistic sensitivity analyses were performed to test the stability of the model.

RESULTS

The direct VAD group had less lifetime costs (USD 95 910 vs USD 129 516) but higher lifetime QALYs than the double bridges group (1.73 vs 0.89). The sensitivity analysis revealed that the direct VAD group consistently had lower cost and higher QALYs during all variations in model parameters. The probability that direct VAD was cost-effective exceeded 75% at any levels of willing-to-pay.

CONCLUSION

From a health insurance payer perspective, direct VAD bridge to heart transplantation appeared to be more cost-effective than double bridges in patients with refractory heart failure.

An Alternative Strategy for Bridge-to-Transplant/Recovery in Small Children with Dilated Cardiomyopathy

Dilated cardiomyopathy in children still has a poor prognosis with high rates of mortality and cardiac transplantation (resp. around 20 and 25%). Awaiting transplantation or possible recovery, these pediatric patients are mechanically supported with extracorporeal membrane oxygenation or a paracorporeal ventricular assist device, both resulting in higher survival rates but also entailing considerable risks of infection, thrombosis, or bleeding. A new indication for an old technique, i.e., pulmonary artery banding, presents itself as an interesting alternative to mechanical circulatory support in selected infants and small children with dilated LV cardiomyopathy and preserved RV function. Here we present a brief review of literature and report on two patients in whom PAB has been successfully implemented as either bridge-to-recovery or bridge-to-transplant.