Metabolic rate of neonates with congenital heart disease

Differences in the serum metabolic profile to identify potential biomarkers for cyanotic versus acyanotic heart disease

BACKGROUND

Growth retardation, malnutrition, and failure to thrive are some of the consequences associated with congenital heart diseases. Several metabolic factors such as hypoxia, anoxia, and several genetic factors are believed to alter the energetics of the heart. Timely diagnosis and patient management is one of the major challenges faced by the clinicians in understanding the disease and provide better treatment options. Metabolic profiling has shown to be potential diagnostic tool to understand the disease.

OBJECTIVE

The present experiment was designed as a single center observational pilot study to classify and create diagnostic metabolic signatures associated with the energetics of congenital heart disease in cyanotic and acyanotic groups.

METHODS

Metabolic sera profiles were obtained from 35 patients with cyanotic congenital heart disease (TOF) and 23 patients with acyanotic congenital heart disease (ASD and VSD) using high resolution 1D 1H NMR spectra. Univariate and multivariate statistical analysis were performed to classify particular metabolic disorders associated with cyanotic and acyanotic heart disease.

RESULTS

The results show dysregulations in several metabolites in cyanotic CHD patients versus acyanotic CHD patients. The discriminatory metabolites were further analyzed with area under receiver operating characteristic (AUROC) curve and identified four metabolic entities (i.e. mannose, hydroxyacetone, myoinositol, and creatinine) which could differentiate cyanotic CHDs from acyanotic CHDs with higher specificity.

CONCLUSION

An untargeted metabolic approach proved to be helpful for the detection and distinction of disease-causing metabolites in cyanotic patients from acyanotic ones and can be useful for designing better and personalized treatment protocol.

Dynamic brain-body coupling of breath-by-breath O2-CO2 exchange ratio with resting state cerebral hemodynamic fluctuations

BACKGROUND

The origin of low frequency cerebral hemodynamic fluctuations (CHF) in the resting state remains unknown. Breath-by breath O2-CO2 exchange ratio (bER) has been reported to correlate with the cerebrovascular response to brief breath hold challenge at the frequency range of 0.008-0.03Hz in healthy adults. bER is defined as the ratio of the change in the partial pressure of oxygen (ΔPO2) to that of carbon dioxide (ΔPCO2) between end inspiration and end expiration. In this study, we aimed to investigate the contribution of respiratory gas exchange (RGE) metrics (bER, ΔPO2 and ΔPCO2) to low frequency CHF during spontaneous breathing.

METHODS

Twenty-two healthy adults were included. We used transcranial Doppler sonography to evaluate CHF by measuring the changes in cerebral blood flow velocity (ΔCBFv) in bilateral middle cerebral arteries. The regional CHF were mapped with blood oxygenation level dependent (ΔBOLD) signal changes using functional magnetic resonance imaging. Temporal features and frequency characteristics of RGE metrics during spontaneous breathing were examined, and the simultaneous measurements of RGE metrics and CHF (ΔCBFv and ΔBOLD) were studied for their correlation.

RESULTS

We found that the time courses of ΔPO2 and ΔPCO2 were interdependent but not redundant. The oscillations of RGE metrics were coherent with resting state CHF at the frequency range of 0.008-0.03Hz. Both bER and ΔPO2 were superior to ΔPCO2 in association with CHF while CHF could correlate more strongly with bER than with ΔPO2 in some brain regions. Brain regions with the strongest coupling between bER and ΔBOLD overlapped with many areas of default mode network including precuneus and posterior cingulate.

CONCLUSION

Although the physiological mechanisms underlying the strong correlation between bER and CHF are unclear, our findings suggest the contribution of bER to low frequency resting state CHF, providing a novel insight of brain-body interaction via CHF and oscillations of RGE metrics.

Associations between anthropometric indices and outcomes of congenital heart operations in infants and young children: An analysis of data from the Society of Thoracic Surgeons Database

BACKGROUND

Children with congenital heart disease are at risk for growth failure due to inadequate nutrient intake and increased metabolic demands. We examined the relationship between anthropometric indices of nutrition (height-for-age z-score [HAZ], weight-for-age z-score [WAZ], weight-for-height z-score [WHZ]) and outcomes in a large sample of children undergoing surgery for congenital heart disease.

METHODS

Patients in the Society of Thoracic Surgeons Congenital Heart Surgery Database having index cardiac surgery at age 1 month to 10 years were included. Indices were calculated by comparing patients' weight and height to population norms from the World Health Organization and Centers for Disease Control and Prevention. Outcomes included operative mortality, composite mortality or major complication, major postoperative infection, and postoperative length of stay. For each outcome and index, the adjusted odds ratio (aOR) (for mortality, composite outcome, and infection) and adjusted relative change in median (for postoperative length of stay) for a 1-unit decrease in index were estimated using mixed-effects logistic and log-linear regression models.

RESULTS

Every unit decrease in HAZ was associated with 1.40 aOR of mortality (95% CI 1.32-1.48), and every unit decrease in WAZ was associated with 1.33 aOR for mortality (95% CI 1.25-1.41). The relationship between WHZ and outcome was nonlinear, with aOR of mortality of 0.84 (95% CI 0.76-0.93) for 1-unit decrease when WHZ ≥ 0 and a nonsignificant association for WHZ < 0. Trends for other outcomes were similar. Overall, the incidence of low nutritional indices was similar for 1-ventricle and 2-ventricle patients. Children between the age of 1 month and 1 year and those with lesions associated with pulmonary overcirculation had the highest incidence of low nutritional indices.

CONCLUSIONS

Lower HAZ and WAZ, suggestive of malnutrition, are associated with increased mortality and other adverse outcomes after cardiac surgery in infants and young children. Higher WHZ over zero, suggestive of obesity, is also associated with adverse outcomes.

Preoperative malnutrition is associated with increased mortality and adverse outcomes after paediatric cardiac surgery

BACKGROUND

Malnutrition is common in children with CHD and is likely to place them at an increased risk for adverse surgical outcomes. We sought to evaluate the impact of preoperative malnutrition on outcomes after paediatric cardiac surgery.

METHODS

We conducted a retrospective analysis of patients from age 0 to 5 years undergoing cardiac surgery at Seattle Children's Hospital from 2006 to 2015. We used regression modelling to examine the impact of malnutrition on surgical outcomes.

RESULTS

We found a non-linear relationship between low height-for-age and weight-for-age z-scores and mortality after surgery. In the range of z-score ⩽-2, each additional unit decrease in height-for-age or weight-for-age z-score was associated with a 2.9 or 2.1% increased risk for mortality, respectively. Each unit decrease in height-for-age z-score was associated with a 1.2% increased risk for cardiac arrest, 1.1% increased risk for infection, and an average of 1.7 additional hours of mechanical ventilation, 6 hours longer ICU stay, and 13 hours longer hospital stay. Each unit decrease in weight-for-age z-score was associated with a 0.7% increased risk for cardiac arrest, 0.8% increased risk for infection, and an average of 1.9 additional hours of mechanical ventilation and 5.3 additional hours of ICU stay.

CONCLUSIONS

This study is unique in demonstrating a significant association between malnutrition and 30-day mortality and other adverse outcomes after paediatric cardiac surgery in a mixed population of CHD patients. By evaluating nutritional status as a continuous variable, we were able to clearly distinguish the point at which malnutrition begins to affect mortality.

Nutrition Support for Children Undergoing Congenital Heart Surgeries: A Narrative Review

Energy imbalance in infants and children with congenital heart disease (CHD) is common and influenced by age, underlying cardiac diagnoses, and presence or absence of congestive heart failure. During the surgical hospitalization period, these children are prone to nutritional deterioration due to stress of surgery, anesthetic/perfusion techniques, and postoperative care. Poor nutrition is associated with increased perioperative morbidity and mortality. This review aims to examine various aspects of nutrition in critically ill children with CHD, including (1) energy expenditure, (2) perioperative factors that contribute to energy metabolism, (3) bedside practices that are potentially able to optimize nutrient delivery, and (4) medium- to long-term impact of energy balance on clinical outcomes. We propose a nutrition algorithm to optimize nutrition of these children in the perioperative period where improvements in nutrition status will likely impact surgical outcomes.

Validity of the LaFarge equation for estimation of oxygen consumption in ventilated children with congenital heart disease younger than 3 years--a revisit

Background

The LaFarge equation is the most commonly used equation to estimate oxygen consumption (Vo₂) in patients of all ages with congenital heart disease, although it was generated in patients older than 3 years. We sought to determine the validity of the LaFarge equation in estimating Vo₂ in children younger than 3 years undergoing cardiac catheterization with general anesthesia.

Methods

Vo₂ was measured directly using respiratory mass spectrometry in 75 sedated, paralyzed, and mechanically ventilated children in the pediatric cardiac catheterization laboratory. Age ranged from 0.13 to 24 years; 40 children being younger than 3 years. Estimated values for Vo₂ were calculated using the LaFarge equation for all patients. The agreement between measured and estimated Vo₂ was evaluated by the bias and limits of agreement in the 2 age groups. Regression analysis was used to analyze the influence of age on the agreement.

Results

A failure of agreement between measured and estimated Vo₂ was noted in both groups of children. As compared to the older group of patients, the agreement was significantly poorer in children younger than 3 years, with a significantly greater overestimation introduced by the LaFarge equation (11% ± 21% vs 53% ± 52%, P < .0001).

Conclusion

The LaFarge equation introduces significant error in the estimation of Vo₂ in ventilated patients with congenital heart disease of all ages, particularly in children younger than 3 years.

Growth, nutrition and energy expenditure in pediatric heart failure

Disturbances in growth are often a consequence of congenital heart disease during infancy and childhood. The magnitude of the growth disturbance is generally related to the anatomical lesion and is most severe in infants and children with congestive heart failure. Presently, surgical repair in this population is often delayed in order to permit increased weight gain. Surgery is preformed when a patient reaches an ideal weight and age, or failure to thrive precludes further waiting. The available data indicate that caloric intake in these infants and children may be nearly adequate for age, but is inadequate to permit normal growth rates. Energy expenditure appears to be significantly elevated in this population relative to that of age-matched infants and children. Therefore, while caloric intake may be appropriate for age, increased energy expenditure leaves the infant or child with congenital heart disease with little energy available for growth. More information is needed on energy intakes and expenditures of specific patient populations, and especially of patients with congestive heart failure, before accurate predictions of their metabolic needs are possible. This knowledge may allow us to better meet the nutritional needs of these populations and decrease the risk of malnutrition and failure to thrive, in turn decreasing surgical risk for these patients.

Increased energy expenditure in infants with cyanotic congenital heart disease

Infants with cyanotic congenital heart disease (CCHD) often have reduced weight gain compared with infants in control groups. Our purpose was to conduct a longitudinal study of energy intake, resting energy expenditure (REE), and total energy expenditure (TEE) of a group of infants with CCHD. We hypothesized that increased REE and TEE and decreased energy intake in these infants would lead to reduced growth. Ten infants with uncorrected CCHD and 12 infants in a control group were studied at 2 weeks of age and again at 3 months. Indirect calorimetry was used to determine REE; the doubly labeled water method was used to determine TEE and intake. At 2 weeks and 3 months of age, infants with CCHD weighed significantly less than infants in the control group. No significant difference was seen in energy intake or REE between groups during either period. TEE was slightly but not statistically increased in the CCHD group at 2 weeks (72.6 +/- 17.4 vs 59.8 +/- 10.9 kcal/kg/d) and significantly increased at 3 months (93.6 +/- 23.3 vs 72.2 +/- 13.2 kcal/kg/d, P </=.03). We conclude that increased TEE but not increased REE is a primary factor in the reduced growth in infants with CCHD.

Total but not resting energy expenditure is increased in infants with ventricular septal defects

OBJECTIVE

The purpose of this study was to determine the effect of left-to-right shunting on the resting energy expenditure (REE), total energy expenditure (TEE), and energy intake in a group of 3- to 5-month-old infants with moderate to large unrepaired ventricular septal defects (VSDs) compared with age-matched, healthy infants.

METHODS

Eight infants with VSDs and 10 healthy controls between 3 to 5 months of age participated in the study. Indirect calorimetry was used to measure REE and the doubly-labeled water method was used to measure TEE and energy intake. An echocardiogram and anthropometric measurements were performed on all study participants. Daily urine samples were collected at home for 7 days. Samples were analyzed by isotope ratio mass spectrometry. Data were compared using analysis of variance.

RESULTS

No significant differences were found in REE (VSD, 42.2 +/- 8.7 kcal/kg/d; control, 43.9 +/- 14.1 kcal/kg/d) or energy intake (VSD, 90.8 +/- 19.9 kcal/kg/d; control, 87.1 +/- 11.7 kcal/kg/d) between the groups. The percent total body water was significantly higher in the VSD infants and the percent fat mass was significantly lower. TEE was 40% higher in the VSD group (VSD, 87.6 +/- 10.8 kcal/kg/d; control, 61.9 +/- 10.3 kcal/kg/d). The difference between TEE and REE, reflecting the energy of activity, was 2.5 times greater in the VSD group.

CONCLUSIONS

REE and energy intake are virtually identical between the two groups. Despite this, infants with VSDs have substantially higher TEE than age-matched healthy infants. The large difference between TEE and REE in VSD infants suggests a substantially elevated energy cost of physical activity in these infants. These results demonstrate that, although infants with VSDs may match the energy intake of healthy infants, they are unable to meet their increased energy demands, resulting in growth retardation.

Children with congenital heart disease: a nutrition challenge

Growth in children with congenital heart disease (CHD) is often compromised. For several decades, investigators have tried to identify the factors affecting growth in children with CHD. Cardiac malformations are undoubtedly responsible for malnutrition, which may range from mild undernutrition to severe failure to thrive (FTT). Malnutrition may then significantly undermine the outcome of corrective surgical operations and postoperative recovery. Mechanisms linking CHD to malnutrition may be related either to decreased energy intake and/or to increased energy requirements. Decreased energy intake can involve deficiencies of specific nutrients, or insufficient total caloric intake. Increased respiratory rate accompanying congestive heart failure may be responsible for increased energy requirements. Different types of cardiac malformations and consequent interventions may have different effects on growth and require diverse strategies. Most treatment strategies aim to facilitate "catch-up" growth, providing extra calories and protein that exceed the Recommended Dietary Allowance for age. However, there is no generally accepted set of guidelines that define appropriate caloric intake for catch-up growth. We attempt to identify the most important causes of malnutrition and highlight the most effective nutrition strategies for children with CHD.

The effects of high-energy feeding on energy balance and growth in infants with congenital heart disease and failure to thrive

Failure to thrive (FTT) in infants with congenital heart disease (CHD) can be attributed to their low energy intakes and high resting energy expenditures. Energy intake, energy expenditure and growth were studied in infants with CHD on normal formula feeds and then on feeds supplemented with glucose polymer to see whether supplementation improved energy retention and growth. Mean gross energy intakes increased by 31.7% on high-energy feeding and mean weight gain improved from 1.3 g/kg per d on control to 5.8 g/kg per d on high-energy feeding. Resting oxygen consumption (VO2 ml/kg per min) was not significantly different on the two feeding regimens, although respiratory quotient rose on high-energy feeding reflecting the increased carbohydrate intake. Estimated energy costs of growth on high-energy feeding fell within the previously described range for normal infants. It is recommended that infants with CHD known to be associated with FTT are fed on high-energy diets from the time of diagnosis in order to optimize growth.

Food, growth and congenital heart disease

The effect of congenital heart disease on growth is reviewed. Whether being small matters is questioned, and reasons why infants with congenital heart disease are small are discussed. Methods of improving growth, and catch-up growth are described. Finally management of the child with CHD and failure to thrive is considered.

Why does congenital heart disease cause failure to thrive?

Metabolisable energy intake, determined by bomb calorimetry of food, vomit, stool and urine, and resting metabolism, assessed by respiratory gas exchange, were studied in 21 infants with congenital heart disease and nine control infants. Weight for age, growth rates, and daily metabolisable energy intake per kg tended to be lower in infants with heart disease than in control infants. Resting oxygen consumption was high in those infants with pulmonary hypertension and persistent cardiac failure. Energy intake, as a percentage of that recommended for age, correlated with weight gain, and resting oxygen consumption correlated inversely with both percentage body mass index and relative fatness. Failure to thrive in infants with congenital heart disease may be due to a combination of low energy intakes and, in some cases, high energy requirements allowing insufficient energy for normal growth. Increasing the energy intakes of infants with congenital heart disease may be a way of improving their growth.

Coeliac disease associated with congenital heart disease

Six children with congenital heart disease are described in whom poor growth was found to be due to small-bowel villous atrophy; none was in heart failure and only one was severely cyanosed. Growth improved in all 6 on a gluten-free diet. Gluten enteropathy may be more common than is realised in children with congenital heart disease, and jejunal biopsy should be undertaken early in any patient with poor growth and no heart failure to exclude the coexistence of the condition.

Intestinal function in infants with severe congenital heart disease

We evaluated digestive tract function in 21 young infants with severe congenital heart disease. One group had congestive heart failure and ventricular septal defect or single ventricle; the other had cyanosis and transposition of the great arteries. Enteric protein loss was excessive in eight patients, and steatorrhea was found in five. These abnormalities were mild and not related to the type or severity of the cardiac lesion. Available evidence points to a need of these babies for calories in excess of normal requirements for weight. The present study suggests that in designing dietary regimens for these very sick patients, their potential for defective gastrointestinal function must be considered. Because no consistent pattern of abnormalities in apparent, each patient who fails to thrive may deserve gastroenterologic evaluation.

Nutritional management of the chronically ill child. Congenital heart disease and myelomeningocele

We have presented some of the nutritional complications encountered in two major pediatric congenital disorders. Although these conditions represent two more common major defects, it is unlikely that many health care providers will manage large numbers of these patients. Nevertheless, the nutrition principles apply to other nutritional dilemmas of chronically ill children. When an infant consumes a low volume intake, regardless of etiology, concerns such as provision of adequate nutrition, within the confines of the infant's water balance, become paramount. Methods have been discussed for increasing caloric density and for monitoring dietary safety and adequacy. When an infant has a propensity for becoming obese one needs to consider preventive measures such as providing sound nutrition information, support, and follow-up for both patient and family. Nutritional problems can become magnified unless adequate support is provided for total health and social needs of the family. The role of the dietitian must be one active participation within the the framework of an interdisciplianry team so that appropriate innovative nutrition programs can be developed and implemented.