Medical management of chronic heart failure in children

Incidence and impact of malnutrition in patients with Fontan physiology

BACKGROUND

Single-ventricle patients require a series of surgeries, with the final stage being the Fontan. This form of circulation results in several long-term complications, but the impact and consequences of nutrition status remain unclear. We sought to evaluate the incidence of malnutrition in Fontan patients and the impact on outcomes.

METHODS

This study was a retrospective cohort study of children who underwent Fontan surgery between 1997 and 2018. Clinical, demographic, and nutrition data were collected, including weight, height, body mass index (BMI), and their respective z scores (z score for weight-for-age [WAZ], z score for height-for-age [HAZ], and z score for BMI-for-age [BMIZ]) pre-Fontan, at discharge, 6 months, and 1, 5, and 10 years post-Fontan. Malnutrition status was categorized using the American Society for Parenteral and Enteral Nutrition guidelines and the Michigan MTool. Fontan failure was defined as listing for heart transplant or death.

RESULTS

Of the 69 patients, moderate-severe malnutrition occurred at any time point in 11% (n = 8) by WAZ, 16% (n = 11) by HAZ, and 6% (n = 4) by BMIZ. Moderate-severe malnutrition persisted in 6.5%-12.9% at 10 years post-Fontan. Compared with the pre-Fontan period, there was no change in these parameters over time. There was no statistically significant difference in Fontan failure between degrees of pre-Fontan malnutrition.

CONCLUSION

There is a 6%-16% incidence of moderate-severe malnutrition in Fontan patients. Malnutrition is a condition that remains present in follow-up. There was no association with anthropometric parameters and transplant-free survival. A prospective multi-institutional study is needed to understand the impact of malnutrition on long-term outcomes.

Digoxin Associated With Greater Transplant-Free Survival in High- vs Low-Risk Interstage Patients

BACKGROUND

Digoxin has been associated with reduced interstage mortality for patients with functional single ventricles with aortic hypoplasia or ductal-dependent systemic circulation. The NEONATE (type of stage 1 palliation operation, postoperative extracorporeal membrane oxygenation, discharge with opiates, no digoxin at discharge, postoperative arch obstruction, moderate to severe tricuspid regurgitation without an oxygen requirement, and extra oxygen required at discharge in patients with moderate to severe tricuspid regurgitation) score can stratify patients by risk of death or transplantation (DTx) on the basis of clinical factors. The study investigators suspected a variable transplant-free survival benefit of digoxin in high-risk vs low-risk patients.

METHODS

National Pediatric Cardiology Quality Improvement Collaborative patients discharged after stage 1 palliation with complete data were categorized as high- or low-risk on the basis of a modified NEONATE score. The primary outcome of DTx was evaluated. A mixed-effect regression evaluated associations between digoxin prescription and risk factors.

RESULTS

A total of 1199 patients were included; 399 (33%) were high risk. Baseline demographics were similar between the cohorts. Blalock-Taussig shunt or a hybrid operation, postoperative extracorporeal membrane oxygenation, opiate prescription, and significant tricuspid regurgitation or arch obstruction were more common in high-risk patients. The odds of DTx were 65% lower in high-risk patients prescribed digoxin compared with patients who were not (P = .001). Digoxin prescription was associated with 60.8% lower DTx in the high-risk cohort (7.8% vs 19.9%; P = .001). There was no significant difference in the DTx rate according to digoxin prescription in the low-risk cohort (4.7% vs 5.7%; P = .46). Blalock-Taussig shunt, aortic arch obstruction, and significant tricuspid regurgitation were most strongly associated with deriving a benefit from digoxin.

CONCLUSIONS

Digoxin use is associated with significant improvement in transplant-free survival in high-risk but not in low-risk interstage patients. A tailored approach to the use of digoxin in interstage patients may be warranted.

Metabolic profiles identify circulating biomarkers associated with heart failure in young single ventricle patients

BACKGROUND

Children and young adults with single ventricle (SV) heart disease frequently develop heart failure (HF) that is intractable and difficult to treat. Our understanding of the molecular and biochemical reasons underlying this is imperfect. Thus, there is an urgent need for biomarkers that predict outcome and provide a rational basis for treatment, and advance our understanding of the basis of HF.

OBJECTIVE

We sought to determine if a metabolomic approach would provide biochemical signatures of HF in SV children and young adults. If significant, these analytes might serve as biomarkers to predict outcome and inform on the biological mechanism(s) of HF.

METHODS

We applied a multi-platform metabolomics approach composed of mass spectrometry (MS) and nuclear magnetic resonance (NMR) which yielded 495 and 26 metabolite measurements respectively. The plasma samples came from a cross-sectional set of young SV subjects, ages 2-19 years with ten control (Con) subjects and 16 SV subjects. Of the SV subjects, nine were diagnosed as congestive HF (SVHF), and 7 were not in HF. Metabolomic data were correlated with clinical status to determine if there was a signature associated with HF.

RESULTS

There were no differences in age, height, weight or sex between the 3 cohorts. However, statistical analysis of the metabolomic profiles using ANOVA revealed 44 metabolites with significant differences between cohorts including 41 profiled by MS and 3 by NMR. These metabolites included acylcarnitines, amino acids, and bile acids, which distinguished Con from all SV subjects. Furthermore, metabolite profiles could distinguish between SV and SVHF subjects.

CONCLUSION

These are the first data to demonstrate a clear metabolomic signature associated with HF in children and young adults with SV. Larger studies are warranted to determine if these findings are predictive of progression to HF in time to provide intervention.

Association of Digoxin With Interstage Mortality: Results From the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Use Dataset

BACKGROUND

Mortality for infants with single ventricle congenital heart disease remains as high as 8% to 12% during the interstage period, the time between discharge after the Norwood procedure and before the stage II palliation. The objective of our study was to determine the association between digoxin use and interstage mortality in these infants.

METHODS AND RESULTS

We conducted a retrospective cohort study using the Pediatric Heart Network Single Ventricle Reconstruction Trial public use dataset, which includes data on infants with single right ventricle congenital heart disease randomized to receive either a Blalock-Taussig shunt or right ventricle-to-pulmonary artery shunt during the Norwood procedure at 15 institutions in North America from 2005 to 2008. Parametric survival models were used to compare the risk of interstage mortality between those discharged to home on digoxin versus those discharged to home not on digoxin, adjusting for center volume, ascending aorta diameter, shunt type, and socioeconomic status. Of the 330 infants eligible for this study, 102 (31%) were discharged home on digoxin. Interstage mortality for those not on digoxin was 12.3%, compared to 2.9% among those on digoxin, with an adjusted hazard ratio of 3.5 (95% CI, 1.1-11.7; P=0.04). The number needed to treat to prevent 1 death was 11 patients. There were no differences in complications between the 2 groups during the interstage period.

CONCLUSIONS

Digoxin use in infants with single ventricle congenital heart disease is associated with significantly reduced interstage mortality.

Current management of pediatric dilated cardiomyopathy

PURPOSE OF REVIEW

American and European guidelines for treatment of adult heart failure have been recently revised. This review will reconcile those guidelines to recent studies and experience in the treatment of pediatric dilated cardiomyopathy.

RECENT FINDINGS

Therapy for pediatric dilated cardiomyopathy includes establishing a diagnosis for diagnostic-specific therapies as well as preventive strategies for anthracycline toxicity and muscular dystrophy. Pediatric studies demonstrate safety and efficacy for use of angiotensin-converting enzyme inhibition and beta-blockers in dilated cardiomyopathy. Cardiac resynchronization and mitral annuloplasty represent potential nonpharmacologic therapies. Implantable defibrillator therapy may be of less import in children as compared with adults. Ventricular assist devices (VADs) are now available for all ages, which can improve survival and potentially can lead to recovery.

SUMMARY

The robust development of new therapies for adult heart failure has been successfully applied to children with dilated cardiomyopathy. Therapies for severe, intractable heart failure have been more widely utilized than therapies for mild-to-moderate heart failure.

Nutrition Implications of Heart Failure and Heart Transplantation in Children With Dilated Cardiomyopathy

This article describes nutrition implications of pediatric dilated cardiomyopathy leading to heart transplantation with a focus on nutritional management of patients during the waiting time for a donor organ and the inpatient postoperative period. Optimization of nutritional status is essential during these periods as weight loss and malnutrition contribute to muscle atrophy, decreased functional capacity, reduced immune function, and prolonged hospital stay. Nutrition implications of heart failure vary with patient’s age and degree of symptoms. Infants may have increased caloric needs and poor feeding often due to tachypnea. Older children, 1-18 years, may have decreased appetite, abdominal pain, and vomiting. Ventricular assist devices or extracorporeal membrane oxygenation, necessary to sustain life in some cases, have additional nutrition implications related to wound healing from insertion of the device and device-related complications that can include pancreatitis and the need for total parenteral nutrition. Once symptomatic heart failure is relieved and heart transplant occurs, caloric needs often decrease while interest in eating can increase profoundly, changing the overall nutrition diagnosis and the need for nutrition support. A case series involving an infant, a young child, and an adolescent is presented to illustrate nutritional challenges and interventions for pediatric patients awaiting heart transplant and the inpatient postoperative period.

Children with chronic organ failure possibly ending in organ transplantation: a survey in an Italian region of 5,000,000 inhabitants

AIM

The Italian Piedmont region sponsored in 2005 a population-based registry to assess the epidemiology of childhood chronic organ failure involving kidneys, liver, heart or lungs.

METHODS

Patients in chronic organ failure who were younger than 18 years were selected, and entered the registry when accomplishing the standard failure criteria for each organ. The cases were reported by the general paediatricians of the region and integrated with the data gathered by the Children University Hospital, a tertiary care centre.

RESULTS

In Piedmont (647,727 inhabitants < 18 years), a total of 146 children (217 cases per million of paediatric population) were found to be affected by chronic organ failure (mean age 10 years; range 0-17). The organ failure involved kidneys in 68 subjects (48%), liver in 24 (17%), heart in 21 (15%) and lungs in 28 (20%), and was severe in 32 subjects (6 on transplantation waiting list). The most represented disease leading to chronic renal failure was renal hypodysplasia (79%). Chronic liver failure was mostly caused by biliary atresia (30%), autoimmune hepatitis (25%) and Wilson's disease (21%). Dilated cardiomyopathy (62%) and surgically treated congenital cardiopathy were the two leading causes of chronic heart failure. The most represented disease leading to chronic lung failure was cystic fibrosis (89%).

CONCLUSION

This is the first report of the literature focusing on the epidemiology of chronic organ failure in children encompassing a region of 4,000,000 inhabitants. This clinical condition is rare, but medically and socially very demanding not only in childhood but the life along, as most of these patients will need solid organ transplantation decades later.

Indications for Heart Transplantation in Pediatric Heart Disease

Background— Since the initial utilization of heart transplantation as therapy for end-stage pediatric heart disease, improvements have occurred in outcomes with heart transplantation and surgical therapies for congenital heart disease along with the application of medical therapies to pediatric heart failure that have improved outcomes in adults. These events justify a reevaluation of the indications for heart transplantation in congenital heart disease and other causes of pediatric heart failure.

Methods and Results— A working group was commissioned to review accumulated experience with pediatric heart transplantation and its use in patients with unrepaired and/or previously repaired or palliated congenital heart disease (children and adults), in patients with pediatric cardiomyopathies, and in pediatric patients with prior heart transplantation. Evidence-based guidelines for the indications for heart transplantation or retransplantation for these conditions were developed.

Conclusions— This evaluation has led to the development and refinement of indications for heart transplantation for patients with congenital heart disease and pediatric cardiomyopathies in addition to indications for pediatric heart retransplantation.

Effects of therapeutic beta blockade on myocardial function and cardiac remodelling in congenital cardiac disease

BACKGROUND

Cardiac remodelling is now recognised as an important aspect of cardiovascular disease progression and is, therefore, emerging as a therapeutic target in cardiac failure due to different etiologies. Little is known about the influence of different therapies for cardiac failure on the remodelling seen in infants with congenital cardiac disease.

METHODS

During follow-up of a prospective and randomized trial, we investigated therapeutic effects on neurohormonal activation, ventricular function, and myocardial gene expression. We compared the data from 8 infants with severe congestive heart failure due to left-to-right shunts, who received digoxin and diuretics alone, to 9 infants who received additional treatment with propranolol.

RESULTS

In these infants, beta-adrenergic blockade significantly reduced highly elevated levels of renin, from 284 +/- 319 microU/ml compared to 1061 +/- 769 microU/ml. Systolic ventricular function was normal in both groups, but diastolic ventricular function was improved in those receiving propranolol, indicated by significantly lower left atrial pressures, lower end-diastolic pressures, and less pronounced ventricular hypertrophy, the latter estimated by lower ratios of myocardial wall to ventricular cavity areas on average of 42%. Further hemodynamic parameters showed no significant differences between the groups, except for the lower heart rate in infants treated with propranolol. In those treated with digoxin and diuretics, there was a significant downregulation of beta2-receptor and angiotensin-2 receptor genes, and up-regulation of endothelin A receptor and connective tissue growth factor genes, that were partially prevented by additional treatment with propranolol.

CONCLUSIONS

Beta-blockade is a new therapeutic approach for congestive heart failure in infants with congenital cardiac disease, producing with significant benefits on neurohormonal activation, diastolic ventricular function, and cardiac remodelling.