Neonates with hypoplastic left heart syndrome have ultrasound evidence of abnormal superior mesenteric artery perfusion before and after modified Norwood procedure

Risk Factors for Adverse Outcomes in Term Infants with CHD and Definitive Necrotising Enterocolitis

OBJECTIVES

To define the incidence of definitive necrotising enterocolitis in term infants with CHD and identify risk factors for morbidity/mortality.

METHODS

We performed a 20-year (2000-2020) single-institution retrospective cohort study of term infants with CHD admitted to the Boston Children's Hospital cardiac ICU with necrotising enterocolitis (Bell's stage ≥ II). The primary outcome was a composite of in-hospital mortality and post-necrotising enterocolitis morbidity (need for extracorporeal membrane oxygenation, multisystem organ failure based on the paediatric sequential organ failure assessment score, and/or need for acute gastrointestinal intervention). Predictors included patient characteristics, cardiac diagnosis/interventions, feeding regimen, and severity measures.

RESULTS

Of 3933 term infants with CHD, 2.1% (n = 82) developed necrotising enterocolitis, with 67% diagnosed post-cardiac intervention. Thirty (37%) met criteria for the primary outcome. In-hospital mortality occurred in 14 infants (17%), of which nine (11%) deaths were attributable to necrotising enterocolitis. Independent predictors of the primary outcome included moderate to severe systolic ventricular dysfunction (odds ratio 13.4,confidence intervals 1.13-159) and central line infections pre-necrotising enterocolitis diagnosis (odds ratio 17.7, confidence intervals 3.21-97.0) and mechanical ventilation post-necrotising enterocolitis diagnosis (odds ratio 13.5, confidence intervals 3.34-54.4). Single ventricle, ductal dependency, and feeding related factors were not independently associated with the primary outcome.

CONCLUSIONS

The incidence of necrotising enterocolitis was 2.1% in term infants with CHD. Adverse outcomes occurred in greater than 30% of patients. Presence of systolic dysfunction and central line infections prior to diagnosis and need for mechanical ventilation after diagnosis of necrotising enterocolitis can inform risk triage and prognostic counseling for families.

Nutrition for Infants with Congenital Heart Disease

Perioperative malnutrition in infants with congenital heart disease can lead to significant postnatal growth failure and poor short- and long-term outcomes. A standardized approach to nutrition is needed for the neonatal congenital heart disease population, taking into consideration the type of cardiac lesion, the preoperative and postoperative period, and prematurity. Early enteral feeding is beneficial and should be paired with parenteral nutrition to meet the fluid and nutrient needs of the infant.

Cardiovascular intensive care unit variables inform need for feeding tube utilization in infants with hypoplastic left heart syndrome

OBJECTIVE

Feeding strategies in infants with hypoplastic left heart syndrome (HLHS) following stage 1 palliation (S1P) include feeding tube utilization (FTU). Timely identification of infants who will fail oral feeding could mitigate morbidity in this vulnerable population. We aimed to develop a novel clinical risk prediction score for FTU.

METHODS

This was a retrospective study of infants with HLHS admitted to the Boston Children's Hospital cardiovascular intensive care unit for S1P from 2009 to 2019. Infants discharged with feeding tubes were compared with those on full oral feeds. Variables from early (birth to surgery), mid (postsurgery to cardiovascular intensive care unit transfer), and late (inpatient transfer to discharge) hospitalization were analyzed in univariate and multivariable models.

RESULTS

Of 180 infants, 66 (36.7%) discharged with a feeding tube. In univariate analyses, presence of a genetic disorder (early variable, odds ratio, 3.25; P = .014) and nearly all mid and late variables were associated with FTU. In the mid multivariable model, abnormal head imaging, ventilation duration, and vocal cord dysfunction were independent predictors of FTU (c-statistic 0.87). Addition of late variables minimally improved the model (c-statistic 0.91). A risk score (the HV2 score) for FTU was developed based on the mid multivariable model with high specificity (93%).

CONCLUSIONS

Abnormal head imaging, duration of ventilation, and presence of vocal cord dysfunction were associated with FTU in infants with HLHS following S1P. The predictive HV2 risk score supports routine perioperative head imaging and vocal cord evaluation. Future application of the HV2 score may improve nutritional morbidity and hospital length of stay in this population.

Feeding Neonates and Infants Prior to Surgery for Congenital Heart Defects: Systematic Review and Meta-Analysis

BACKGROUND

Necrotising enterocolitis (NEC) is a significant cause of mortality and morbidity in neonates requiring cardiac surgery. Feeding practices vary significantly across institutions and remain controversial. We conducted a systematic review of the literature and a meta-analysis to identify associations between feeding practices and necrotising enterocolitis.

METHODS

This study was carried out in accordance with the PRISMA guidelines. A literature search was performed in November 2022 using the Cochrane Central Register, Embase, and Pubmed. Two investigators then independently retrieved eligible manuscripts considered suitable for inclusion. Data extracted included gestational age, birth weight, sex, nature of congenital heart lesion, type of operation performed, time on ventilator, ICU stay, hospital stay, post-operative feeding strategy, and complications. The methodological quality was assessed using the Downs and Black score for all randomised control trials and observational studies.

RESULTS

The initial search yielded 92 studies. After removing duplicates, there were 85 abstracts remaining. After excluding ineligible studies, 8 studies were included for the meta-analysis. There was no significant risk of NEC associated with pre-operative feeding [OR = 1.22 (95% CI 0.77,1.92)] or umbilical artery catheter placement [OR = 0.91 (95% CI 0.44, 1.89)] and neither outcome exhibited heterogeneity [I² = 8% and 0%, respectively]. There was a significant association between HLHS and NEC [OR = 2.56 (95% CI 1.56, 4.19)] as well as prematurity and NEC [OR 3.34 (95% CI 1.94, 5.75)] and neither outcome exhibited heterogeneity [I² = 0% and 0%, respectively].

CONCLUSIONS

There was no association between NEC and pre-operative feeding status in neonates awaiting cardiac surgery. Pre-operative feeding status was not associated with prolonged hospital stay or need for tube assisted feeding at discharge. HLHS and prematurity were associated with increased incidence of NEC.

Nutritional Considerations for the Neonate With Congenital Heart Disease

The importance of nutrition in managing critically ill infants with congenital heart disease (CHD) is foundational to optimizing short- and long-term health outcomes. Growth failure and malnutrition are common in infants with CHD. The etiology of growth failure in this population is often multifactorial and may be related to altered metabolic demands, compromised blood flow to the intestine leading to nutrient malabsorption, cellular hypoxia, inadequate energy intake, and poor oral-motor skills. A dearth of high-quality studies and gaps in previously published guidelines have led to wide variability in nutrition practices that are locally driven. This review provides recommendations from the nutrition subgroup of the Neonatal Cardiac Care Collaborative for best evidence-based practices in the provision of nutritional support in infants with CHD. The review of evidence and recommendations focused on 6 predefined areas of clinical care for a target population of infants <6 months with CHD admitted to the ICU or inpatient ward. These areas include energy needs, nutrient requirements, enteral nutrition, feeding practice, parenteral nutrition, and outcomes. Future progress will be directed at quality improvement efforts to optimize perioperative nutrition management with an increasing emphasis on individualized care based on nutritional status, cardiorespiratory physiology, state of illness, and other vulnerabilities.

Clinical Characteristics and Potential Pathogenesis of Cardiac Necrotizing Enterocolitis in Neonates with Congenital Heart Disease: A Narrative Review

Neonates with congenital heart disease (CHD) are at an increased risk of developing necrotizing enterocolitis (NEC), an acute inflammatory intestinal injury most commonly associated with preterm infants. The rarity of this complex disease, termed cardiac NEC, has resulted in a dearth of information on its pathophysiology. However, a higher incidence in term infants, effects on more distal regions of the intestine, and potentially a differential immune response may distinguish cardiac NEC as a distinct condition from the more common preterm, classical NEC. In this review, risk factors, differentiated from those of classical NEC, are discussed according to their potential contribution to the disease process, and a general pathogenesis is postulated for cardiac NEC. Additionally, biomarkers specific to cardiac NEC, clinical outcomes, and strategies for achieving enteral feeds are discussed. Working towards an understanding of the mechanisms underlying cardiac NEC may aid in future diagnosis of the condition and provide potential therapeutic targets.

Necrotizing Enterocolitis in Children with Congenital Heart Disease: A Literature Review

Infants with congenital heart disease (CHD) are at an increased risk of developing necrotising enterocolitis (NEC), a serious inflammatory intestinal condition classically associated with prematurity. CHD not only increases the risk of NEC in preterm infants but is one of the most commonly implicated risk factors in term infants. Existing knowledge on the topic is limited largely to retrospective studies. This review acts to consolidate existing knowledge on the topic in terms of disease incidence, pathophysiology, risk factors, outcomes and the complex relationship between NEC and enteral feeds. Potential preventative strategies, novel biomarkers for NEC in this population, and the role of the intestinal microbiome are all explored. Numerous challenges exist in the study of this complex multifactorial disease which arise from the heterogeneity of the affected population and its relative scarcity. Nevertheless, its high related morbidity and mortality warrant renewed interest in identifying those infants most at risk and implementing strategies to reduce the incidence of NEC in infants with CHD.

The Relationship Between Preoperative Feeding Exposures and Postoperative Outcomes in Infants With Congenital Heart Disease

OBJECTIVES

To evaluate the association of preoperative risk factors and postoperative outcomes in infants with complex congenital heart disease.

DESIGN

Single-center retrospective cohort study.

SETTING

Neonatal ICU and cardiovascular ICU.

PATIENTS

Infants of all gestational ages, born at Texas Children's Hospital between 2010 and 2016, with complex congenital heart disease requiring intervention prior to discharge.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 399 patients were enrolled in the study. Preoperative risk factors included feeding, type of feeding, feeding route, and cardiac lesion. Postoperative outcomes included necrotizing enterocolitis, hospital length of stay, and days to full feeds. The occurrence rate of postoperative necrotizing enterocolitis (all stages) was 8%. Preoperative feeding, type of feeding, feeding route, and cardiac lesion were not associated with higher odds of postoperative necrotizing enterocolitis. Cardiac lesions with ductal-dependent systemic blood flow were associated with a hospital length of stay of 19.6 days longer than those with ductal-dependent pulmonary blood flow (p < 0.001) and 2.9 days longer to reach full feeds than those with ductal-dependent pulmonary blood flow (p < 0.001), after controlling for prematurity. Nasogastric feeding route preoperatively was associated with a length of stay of 29.8 days longer than those fed by mouth (p < 0.001) and 2.4 days longer to achieve full feeds (p < 0.001), after controlling for prematurity and cardiac lesion. Preoperative diet itself was not associated with significant change in length of stay or days to reach full feeds.

CONCLUSIONS

Although cardiac lesions with ductal-dependent systemic blood flow are considered high risk and may increase length of stay and days to achieve full feeds, they are not associated with a higher risk of postoperative necrotizing enterocolitis. Nasogastric route is not associated with a significantly higher risk of necrotizing enterocolitis, but longer length of stay and days to reach full feeds. These findings challenge our perioperative management strategies in caring for these infants, as they may incur more hospital costs and resources without significant medical benefit.

Arch intervention following stage 1 palliation in hypoplastic left heart syndrome is associated with slower feed advancement: a report from the National Pediatric Quality Cardiology Improvement Collaborative

INTRODUCTION

Infants undergoing stage 1 palliation for hypoplastic left heart syndrome may have post-operative feeding difficulties. Although the cause of feeding difficulties in these patients is multi-factorial, residual arch obstruction may affect gut perfusion, contributing to feeding intolerance. We hypothesised that undergoing arch reintervention following stage 1 palliation would be associated with post-operative feeding difficulties.

METHODS

This was a retrospective cohort study. We analysed data from the National Pediatric Cardiology Quality Improvement Collaborative, which maintains a multicentre registry for infants with hypoplastic left heart syndrome discharged home following stage 1 palliation. Patients who underwent arch reintervention (percutaneous or surgical) prior to discharge following stage 1 palliation were compared with those who underwent non-aortic arch interventions after stage 1 palliation and those who underwent no intervention. Median post-operative days to full enteral feeds and weight for age z-scores were compared. Predictors of post-operative days to full feeds were identified.

RESULTS

Among patients who underwent arch reintervention, post-operative days to full enteral feeds were greater than for those who underwent non-aortic arch interventions (25 versus 16, p = 0.003) or no intervention (median days 25 versus 12, p < 0.001). Arch intervention, multiple interventions, gestational age, and the presence of a gastrointestinal anomaly were predictors of days to full feeds.

CONCLUSIONS

Repeat arch intervention is associated with a longer time to achieve full enteral feeding in patients with hypoplastic left heart syndrome after stage 1 palliation. Further investigation of this association is needed to understand the role of arch obstruction in feeding problems in these patients.

Preoperative Feeds in Ductal-Dependent Cardiac Disease: A Systematic Review and Meta-analysis

CONTEXT

Our aim for this review is to determine if preoperative feeds in neonates with ductal-dependent congenital heart disease are harmful or beneficial.

OBJECTIVES

To summarize current evidence for preoperative feeding in neonates with ductal-dependent congenital heart disease.

DATA SOURCES

We used the following databases: Medline, Embase, and Cochrane Central Register of Controlled Trials.

STUDY SELECTION

We included observational studies in which the following outcomes were addressed: necrotizing enterocolitis (NEC), hospital length of stay (LOS), time to achieve full postoperative enteral feeding, and feeding intolerance.

DATA EXTRACTION

Two reviewers independently screened each study for eligibility and extracted data. Methodologic quality was assessed by using a standardized item bank, and certainty of evidence for each outcome was assessed by using Grading of Recommendations Assessment, Development and Evaluation criteria.

RESULTS

Five retrospective cohort studies were eligible for inclusion, for which risk of bias was significant. When comparing neonates who received preoperative feeds with those who did not, there was no significant difference in NEC (pooled odds ratio = 1.09 [95% confidence interval 0.06-21.00; P = .95]; 3 studies, 6807 participants, very low certainty evidence), hospital LOS (mean of 14 days for those not fed versus 9.9 days for those fed preoperatively; P < .01; 1 study, 57 participants, very low certainty evidence), or feeding intolerance (odds ratio = 2.014 [95% confidence interval 0.079-51.703; P = .67]; 1 study, 56 participants, very low certainty evidence). No data were available for the outcome time to achieve full postoperative enteral feeding. All studies were observational and had small sample sizes.

CONCLUSIONS

There is insufficient evidence to suggest that preoperative enteral feeds in patients with ductal-dependent cardiac lesions adversely influence the rate of NEC, LOS, or feeding intolerance.

Standardized Feeding Protocols to Reduce Risk of Necrotizing Enterocolitis in Fragile Infants Born Premature or with Congenital Heart Disease: Implementation Science Needed

Although a unit-adopted standardized feeding protocol (SFP) for neonates is standard of care, implementation strategies for SFPs vary across neonatal and pediatric intensive care. Besides improving growth and reducing feeding interruptions, SFPs reduce risk for necrotizing enterocolitis in infants with heart disease or born premature. The purpose of this article is to bridge the gap between recommended and actual care using SFPs.

Consideration of pyloric stenosis as a cause of feeding dysfunction in children with cyanotic heart disease

Feeding difficulty has been reported at a higher incidence in infants with cyanotic heart disease and single ventricle physiology necessitating specialized feeding strategies. However, structural causes of feed intolerance in this subset of patients should not be ignored. This case series highlights three recent cases of pyloric stenosis in infants with left-sided obstructive lesions at our institution. In all three cases, the initial presumed diagnosis was feeding intolerance related to heart disease, and there was significant clinical improvement following identification and correction of pyloric stenosis.

Preoperative Feeding Neonates With Cardiac Disease

BACKGROUND

The potential for necrotizing enterocolitis (NEC) in neonates requiring cardiac surgery has contributed largely to wide feeding practice variations and a hesitation to initiate enteral feeding during the preoperative period, specifically those patients with hypoplastic left heart syndrome.

METHODS

A retrospective chart review of neonates undergoing cardiac surgery at a single institution between July 2011 and July 2013 was performed. The primary objective of this study was to determine if preoperative feeding was associated with NEC in neonates requiring cardiac surgery. Univariable and multivariable analyses were performed to evaluate the relationship between preoperative feeding and NEC. Secondary outcomes including growth failure, total ventilator days, total length of stay, and tube-assisted feeds at discharge were analyzed.

RESULTS

One hundred thirty consecutive neonates who required cardiac surgery were included in the analysis. Preoperative feeding occurred in 61% (n = 79). The overall prevalence of NEC was 9% (12/130), including three neonates with surgical NEC. There was no difference in the prevalence of NEC between the preoperative feeding and nil per os (NPO) groups. Preoperative NPO status was associated with longer ventilator-dependent days ( P = .01) but was not associated with worsened growth failure, longer length of stay, or increased prevalence of tube-assisted feeds at discharge.

CONCLUSION

In this study cohort, preoperative feeding was associated with a low prevalence of NEC. Larger prospective studies evaluating the safety and benefits of preoperative feeding in cardiac neonates are warranted.

Early hybrid approach and enteral feeding algorithm could reduce the incidence of necrotising enterocolitis in neonates with ductus-dependent systemic circulation

BACKGROUND

The reported incidence of necrotising enterocolitis in neonates with complex CHD with ductus-dependent systemic circulation ranges from 6.8 to 13% despite surgical treatment; the overall mortality is between 25 and 97%. The incidence of gastrointestinal complications after hybrid palliation for neonates with ductus-dependent systemic circulation still has to be defined, but seems comparable with that following the Norwood procedure.

METHODS

We reviewed the incidence of gastrointestinal complications in a series of 42 consecutive neonates with ductus-dependent systemic circulation, who received early hybrid palliation associated with a standardised feeding protocol.

RESULTS

The median age and birth weight at the time of surgery were 3 days (with a range from 1 to 10 days) and 3.07 kg (with a range from 1.5 to 4.5 kg), respectively. The median ICU length of stay was 7 days (1-70 days), and the median hospital length of stay was 16 days (6-70 days). The median duration of mechanical ventilation was 3 days. Hospital mortality was 16% (7/42). In the postoperative period, 26% of patients were subjected to early extubation, and all of them received treatment with systemic vasodilatory agents. Feeding was started 6 hours after extubation according to a dedicated feeding protocol. After treatment, none of our patients experienced any grade of necrotising enterocolitis or major gastrointestinal adverse events.

CONCLUSIONS

Our experience indicates that the combination of an "early hybrid approach", systemic vasodilator therapy, and dedicated feeding protocol adherence could reduce the incidence of gastrointestinal complications in this group of neonates. Fast weaning from ventilatory support, which represents a part of our treatment strategy, could be associated with low incidence of necrotising enterocolitis.

Results of a Feeding Protocol in Patients Undergoing the Hybrid Procedure

Neonates with single-ventricle physiology are at increased risk of developing gastrointestinal morbidities. Feeding protocols in this patient population have been shown to decrease feeding complications after the Norwood procedure, but no data exist to determine the effectiveness of a feeding protocol in patients undergoing the hybrid procedure. Goal of this study was to examine the impact of a standardized feeding protocol on the incidence of overall postoperative gastrointestinal morbidity after the hybrid procedure. Retrospective chart review was performed on neonates undergoing the hybrid procedure. Neonates were divided into two groups, pre-feeding protocol (pre-FP), which encompassed the years 2002-2008, and post-feeding protocol (post-FP), which encompassed the years 2011-2014. Preoperative, operative, and postoperative data were collected. T test or Fisher's exact test was used for analysis. p < 0.05 was considered significant. Seventy-three neonates were in the pre-FP and 52 neonates were in the post-FP. There were no significant differences between the pre-FP and the post-FP in cardiac diagnosis (62 HLHS, 11 other vs. 39 HLHS, 13 other, respectively). Pre-FP underwent hybrid procedure later than the post-FP (9.1 ± 5.8 vs. 5.7 ± 3.4 days, respectively, p < 0.01) and achieved full enteral feeds earlier than the post-FP (3.2 + 2.9 vs. 7.8 + 3.9 days, respectively, p < 0.01). The incidence of necrotizing enterocolitis was higher in the pre-FP versus post-FP [11.0 % (8/65) vs. 5.8 % (3/49), respectively, p = 0.36]. Though not significant, the incidence of necrotizing enterocolitis decreased by almost 50 % after initiating a feeding protocol in patients undergoing the hybrid procedure. This is consistent with previous studies showing beneficial results of a feeding protocol in this complex patient population.

Mesenteric near-infrared spectroscopy and risk of gastrointestinal complications in infants undergoing surgery for congenital heart disease

We hypothesised that lower mesenteric near-infrared spectroscopy values would be associated with a greater incidence of gastrointestinal complications in children weighing <10 kg who were recovering from cardiac surgery. We evaluated mesenteric near-infrared spectroscopy, central venous oxygen saturation, and arterial blood gases for 48 hours post-operatively. Enteral feeding intake, gastrointestinal complications, and markers of organ dysfunction were monitored for 7 days. A total of 50 children, with median age of 16.7 (3.2-31.6) weeks, were studied. On admission, the average mesenteric near-infrared spectroscopy value was 71±18%, and the systemic oxygen saturation was 93±7.5%. Lower admission mesenteric near-infrared spectroscopy correlated with longer time to establish enteral feeds (r=-0.58, p<0.01) and shorter duration of feeds at 7 days (r=0.48, p<0.01). Children with gastrointestinal complications had significantly lower admission mesenteric near-infrared spectroscopy (58±18% versus 73±17%, p=0.01) and higher mesenteric arteriovenous difference of oxygen at admission [39 (23-47) % versus 19 (4-27) %, p=0.02]. Based on multiple logistic regression, admission mesenteric near-infrared spectroscopy was independently associated with gastrointestinal complications (Odds ratio, 0.95; 95% confidence interval, 0.93-0.97; p=0.03). Admission mesenteric near-infrared spectroscopy showed an area under the receiver operating characteristic curve of 0.76 to identify children who developed gastrointestinal complications, with a suggested cut-off value of 72% (78% sensitivity, 68% specificity). In this pilot study, we conclude that admission mesenteric near-infrared spectroscopy is associated with gastrointestinal complications and enteral feeding tolerance in children after cardiac surgery.

Nutrition in the Cardiac Newborns: Evidence-based Nutrition Guidelines for Cardiac Newborns

Both protein and energy malnutrition are common in neonates and infants with congenital heart disease (CHD). Neonates with CHD are at increased risk of developing necrotizing enterocolitis (NEC), particularly the preterm population. Mortality in patients with CHD and NEC is higher than for either disease process alone. Standardized feeding protocols may affect both incidence of NEC and growth failure in infants with CHD. The roles of human milk and probiotics have not yet been explored in this patient population.

Total Energy Expenditure of Infants with Congenital Heart Disease Who Have Undergone Surgical Intervention

Growth failure is often observed in infants with congenital heart disease (CHD); it is unclear, however, whether growth failure is due to increased total energy expenditure (TEE). An observational study of infants with CHD and surgical intervention within the first 30 days of life and healthy infants of similar age was undertaken. TEE was measured using the doubly labeled water method in 3-month-old infants (n = 15 CHD, 12 healthy) and 12-month-old infants (n = 11 CHD, 12 healthy). Multiple linear regression models were fit to examine the association between health status (CHD vs. healthy) and TEE. The accuracy of equations for calculating TEE was also determined. TEE for CHD infants was not significantly different from healthy infants at 3 and 12 months; TEE in CHD infants was 36.4 kcal/day higher (95 % CI -46.3, 119.2; p = 0.37) and 31.7 kcal/day higher, (95 % CI -71.5, 134.8; p = 0.53) at 3 and 12 months, respectively, compared to healthy infants. The 2002 Dietary Reference Intake (DRI) equation and the 1989 Recommended Dietary Allowance equation over-estimated measured TEE to a lesser extent than CHD specific equations; the 2002 DRI yielded the smallest mean difference between calculated versus measured TEE (difference 79 kcal/day). During the first year of life, TEE of infants with CHD and interventional surgery within the first month of life was not different than age-matched healthy infants. When calculating TEE of ≤12-month-old infants with CHD who have undergone surgical intervention, the 2002 DRI equation may be used as a starting point for estimating initial clinical energy intake goals.

Perioperative cerebral hemodynamics and oxygen metabolism in neonates with single-ventricle physiology

Congenital heart disease (CHD) patients are at risk for neurodevelopmental delay. The etiology of these delays is unclear, but abnormal prenatal cerebral maturation and postoperative hemodynamic instability likely play a role. A better understanding of these factors is needed to improve neurodevelopmental outcome. In this study, we used bedside frequency-domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) to assess cerebral hemodynamics and oxygen metabolism in neonates with single-ventricle (SV) CHD undergoing surgery and compared them to controls. Our goals were 1) to compare cerebral hemodynamics between unanesthetized SV and healthy neonates, and 2) to determine if FDNIRS-DCS could detect alterations in cerebral hemodynamics beyond cerebral hemoglobin oxygen saturation (SO 2). Eleven SV neonates were recruited and compared to 13 controls. Preoperatively, SV patients showed decreased cerebral blood flow (CBFi ), cerebral oxygen metabolism (CMRO 2i ) and SO 2; and increased oxygen extraction fraction (OEF) compared to controls. Compared to preoperative values, unstable postoperative SV patients had decreased CMRO 2i and CBFi , which returned to baseline when stable. However, SO 2 showed no difference between unstable and stable states. Preoperative SV neonates are flow-limited and show signs of impaired cerebral development compared to controls. FDNIRS-DCS shows potential to improve assessment of cerebral development and postoperative hemodynamics compared to SO 2 alone.

Ultrasound assessment of mesenteric blood flow in neonates with hypoplastic left heart before and after hybrid palliation

BACKGROUND

Altered mesenteric perfusion may be a contributor to the development of necrotising enterocolitis in patients with hypoplastic left heart syndrome. The goal of this study was to document mesenteric flow patterns in patients with hypoplastic left heart syndrome pre- and post-hybrid procedure.

METHODS

A prospective study on all patients with hypoplatic left heart syndrome undergoing the hybrid procedure was conducted. Doppler ultrasound analysis of the coeliac and superior mesenteric artery was performed.

RESULTS

A total of 13 patients were evaluated. There was a significant difference in the coeliac artery effective velocity-time intergral pre- and post-hybrid procedure (8.69±3.84 versus 12.51±4.95 cm, respectively). There were significant differences in the superior mesenteric artery antegrade velocity-time integral pre- and post-hybrid procedure (6.86±2.45 versus 10.52±2.64 cm, respectively) and superior mesenteric artery effective velocity-time integral pre- and post-hybrid procedure (6.22±2.68 versus 9.73±2.73 cm, respectively). There were no significant differences between the coeliac and superior mesenteric artery Doppler indices in the pre-hybrid procedure; there were, however, significant differences in the post-hybrid procedure between coeliac and superior mesenteric artery antegrade velocity-time integral (13.8 2±5.60 versus 10.52±2.64 cm, respectively) and effective velocity-time integral (13.04±4.71 versus 9.73±2.73 cm, respectively).

CONCLUSION

Doppler mesenteric indices of perfusion improve in patients with hypoplastic left heart syndrome after the hybrid procedure; however, there appears to be preferential flow to the coeliac artery versus the superior mesenteric artery in these patients post-procedure.

Splanchnic near-infrared spectroscopy and risk of necrotizing enterocolitis after neonatal heart surgery

Infants with critical congenital heart disease, especially patients with a single-ventricle (SV) physiology, are at increased risk for the development of necrotizing enterocolitis (NEC). Decreased splanchnic oxygen delivery may contribute to the development of NEC and may be detected by regional oximetry (rSO2) via splanchnic near-infrared spectroscopy (NIRS). This prospective study enrolled 64 neonates undergoing biventricular (BV) repair or SV palliation for CHD and monitored postoperative splanchnic rSO2 before and during initiation of enteral feedings to determine whether changes in rSO2 are associated with risk of NEC. Suspected or proven NEC was observed in 32 % (11/34) of the SV subjects and 0 % (0/30) of the BV subjects (p = 0.001). Compared with the BV subjects, the SV palliated subjects had significantly lower splanchnic rSO2 before and during initiation of enteral feedings, but the groups showed no difference after correction for lower pulse oximetry (SpO2) in the SV group. The clinical parameters were similar among the SV subjects with and without NEC except for cardiopulmonary bypass times, which were longer for the patients who experienced NEC (126 vs 85 min; p = 0.03). No difference was observed in splanchnic rSO2 or in the SpO2-rSO2 difference between the SV subjects with and without NEC. Compared with the patients who had suspected or no NEC, the subjects with proven NEC had a lower average splanchnic rSO2 (32.6 vs 47.0 %; p = 0.05), more time with rSO2 less than 30 % (48.8 vs 6.7 %; p = 0.04) at one-fourth-volume feeds, and more time with SpO2-rSO2 exceeding 50 % (33.3 vs 0 %; p = 0.03) before feeds were initiated. These data suggest that splanchnic NIRS may be a useful tool for assessing risk of NEC, especially in patients with an SV physiology.

[Mesenteric flow in an experimental model of ischaemia-reperfusion in rats]

INTRODUCTION

Maintained acute occlusion followed by reperfusion of the superior mesenteric artery (SMA) in a few hours can trigger irreversible bowel damage. The aim of the study was to determine the changes in mesenteric flow measured by colour Doppler Ultrasound and correlating with histological lesions in an experimental model of ischaemia-reperfusion.

METHOD AND MATERIAL

Three groups of Sprague-Dawley 17 day-old rats were studied (control, ischemia and reperfusion). The model used was ischaemia-reperfusion over the SMA. Intra-abdominal ultrasound was then performed. The parameters recorded were: Maximum systolic velocity (MSV), pulsatility index (PI), resistance (RI) and systole-diastole (S/D). The histological variables were: intestinal lesion (Wallace/Keenan-Chiu scale), morphometrics (mean villus height [MVH]), and goblet cells. The Spearman (rs) correlation was used.

RESULTS

The MSV in the reperfusion group was 74.3 cm/s, the PI 7.33 and S/D 25.75 in the SMA, which were higher than the controls (41.35 cm/s; 3.12 and 12.45, respectively). A direct association (P<.01) was found between MSV, PI and S/D regarding: Wallace/Kennan scoring system (rs = 0.655; rs = 0.593; rs = 0.63) and the Chiu (rs = 0.569; rs = 0.522; rs = 0.47). While the correlation was the reverse (P<.01) when associated with the MVH (rs = -0,495; rs = -0,452; rs = -0,459) and goblet cells of the colon (rs = -0,525; rs = -0,45; rs = -0,518).

CONCLUSIONS

The reperfusion phase increased mesenteric flow expressed by the MSV and PI and could significantly predict the potential bowel damage at macroscopic and microscopic level.

Does milk fortification increase the risk of necrotising enterocolitis in preterm infants with congenital heart disease?

Prematurity and low birth weight adds to the risk of serious congenital heart disease in infants. It may also delay surgical intervention, especially when cardiopulmonary bypass is required, or where an aortopulmonary shunt is necessary to maintain adequate oxygenation. In this setting, neonatologists are faced with the challenge of accelerating the infant's growth to allow for early surgery. We describe the cases of two infants in whom an attempt to fortify the feeds was associated with necrotising enterocolitis, with a lethal outcome in one. The outcome suggests caution in fortifying feeds in premature infants with serious congenital heart disease.

Diastolic flow parameters are not sensitive in predicting necrotizing enterocolitis in patients undergoing hybrid procedure

BACKGROUND

Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality in neonates with complex single-ventricle anatomy undergoing stage I palliation. Hybrid approach is another option for initial single-ventricle palliation. The goal of this study was to determine if there were differences in echocardiographic indices between patients undergoing the hybrid procedure who developed NEC vs. those that did not develop NEC.

METHODS

Retrospective chart review was performed on patients who underwent the hybrid procedure. Patients were included if an echocardiogram with adequate Doppler tracings through the patent ductus arteriosus stent was available. Echocardiographic indices measured included antegrade velocity-time integral (VTI), retrograde VTI, effective VTI, VTI regurgitant fraction, VTI retrograde/VTI antegrade ratio, calculated cardiac output, peak antegrade velocity through the ductal stent, retrograde/antegrade time ratio, and percent regurgitant time. Indices were compared in patients who developed NEC (NEC Group) and those who did not develop NEC (No NEC Group). NEC was defined as a Bell Stage ≥2.

RESULTS

Sixty-nine patients met inclusion criteria. Eight of the 69 patients developed NEC. There was no significant difference between the NEC and No NEC Group for antegrade VTI (10.4 ± 3.2 cm vs. 12.7 ± 4.4 cm), retrograde VTI (5.3 ± 1.5 cm vs. 6.1 ± 2.2 cm), effective VTI (5.1 ± 2.9 cm vs. 6.6 ± 3.3 cm), VTI regurgitant fraction (53.6 ± 14.7% vs. 49.7 ± 13.6%), and VTI retrograde/VTI antegrade ratio (0.54 ± 0.15 vs.0.50 ± 0.14). Cardiac output (4.2 ± 1.4 L/min/m(2) vs. 4.8 ± 1.8 L/min/m(2) ) and peak velocity (117.5 ± 28.9 cm/s and 142.4 ± 42.6 cm/s) were also not different between the NEC and No NEC Groups. Furthermore, retrograde/antegrade time ratios (1.6 ± 0.2 vs. 1.7 ± 0.3) and percent retrograde time (60.6 ± 3.0% vs. 62.0 ± 4.0%) were not different between the NEC and No NEC Groups.

CONCLUSION

Echocardiographic indices were not sensitive in determining the development of NEC in patients undergoing the hybrid procedure. Larger studies with more sensitive imaging techniques are required to help risk stratify NEC in this complex patient population.

Feeding, growth, nutrition, and optimal interstage surveillance for infants with hypoplastic left heart syndrome

Improvement in operative survival of patients with hypoplastic left heart syndrome has led to increasing emphasis on prevention of interstage mortality. Many centres have improved interstage results through programmes of home monitoring following discharge after the Norwood (Stage 1) operation. Experience with heightened interstage surveillance has identified failure to thrive during infancy as a modifiable risk factor for this population, one that has been linked to concerning outcomes at subsequent palliative surgeries. Ensuring normal growth as an infant has thus become a priority of management of patients with functionally univentricular hearts. Herein, we review the existing evidence for best practices in interstage surveillance and optimal nutrition in infants with functionally univentricular hearts. In addition, we highlight data presented at HeartWeek 2011, from Cardiology 2011, the 15th Annual Update on Pediatric and Congenital Cardiovascular Disease, and the 11th Annual International Symposium on Congenital Heart Disease.

Comparison of gastrointestinal morbidity after Norwood and hybrid palliation for complex heart defects

This study aimed to compare the incidence of gastrointestinal complications among infants with single-ventricle heart defects after three first-stage palliation strategies: Norwood-modified Blalock-Taussig shunt (mBTS), Norwood right ventricle-to-pulmonary artery conduit (Sano), and hybrid procedures. A retrospective chart review was performed in a pediatric cardiac intensive care unit at a tertiary care medical center. The subjects were 32 neonates who had undergone single-ventricle palliation including 13 Norwood-mBTS, 11 Sano, and 8 hybrid procedures. The measurements included baseline as well as pre- and postoperative patient characteristics. The primary outcome was postoperative intraabdominal complications, and the secondary outcomes were feeding intolerance and necrotizing enterocolitis (NEC). Intraabdominal complications occurred for 34%, feeding intolerance for 13%, and NEC for 13% of the patients. The hybrid patients had a higher incidence of intraabdominal complications (75%) than the Norwood-mBTS (31%) or Sano (9%) patients (P = 0.01). The relative risk for intraabdominal complications in the hybrid group was 3.6 (95% confidence interval [CI], 1.5-8.7). In the multivariate analysis, the hybrid procedure remained an independent predictor of intraabdominal complications (hazard ratio, 8.4; 95% CI, 2.0-34.5). The hybrid, Norwood-mBTS, and Sano patients did not differ significantly in terms of feeding intolerance (25, 15, and 0%, respectively; P = 0.25) or NEC (25, 8, and 9%; P = 0.46). Gastrointestinal morbidity was common regardless of the palliative approach, although the hybrid patients had the highest incidence of intraabdominal complications. This supports the need for caution in using enteral nutrition with all single-ventricle patients, including the hybrid population. Patients undergoing the hybrid procedure may benefit from implementation of standardized feeding protocols.

Celiac artery flow pattern in infants with single right ventricle following the Norwood procedure with a modified Blalock-Taussig or right ventricle to pulmonary artery shunt

A potential advantage of the right ventricle to pulmonary artery versus modified Blalock-Taussig shunt in patients undergoing the Norwood procedure is limitation of diastolic runoff from the systemic to pulmonary circulation. We evaluated mesenteric flow patterns and gastrointestinal outcomes following the Norwood procedure associated with either shunt type. Patients randomized to a right ventricle to pulmonary artery versus modified Blalock-Taussig shunt in the Pediatric Heart Network Single Ventricle Reconstruction Trial at centers participating in this ancillary study were eligible for inclusion; those with active necrotizing enterocolitis, sepsis, or end-organ dysfunction were excluded. Celiac artery flow characteristics and gastrointestinal outcomes were collected at discharge. Forty-four patients (five centers) were included. Median age at surgery was 5 days [interquartile range (IQR) = 4-8 days]. Median celiac artery resistive index (an indicator of resistance to perfusion) was higher in the modified Blalock-Taussig shunt group (n = 19) versus the right ventricle to pulmonary artery shunt group (n = 25) [1.00 (IQR = 0.84-1.14) vs. 0.82 (IQR = 0.74-1.00), p = 0.02]. There was no difference in interstage weight gain, necrotizing enterocolitis, or feeding intolerance episodes between the groups. The celiac artery resistive index was higher in patients with the modified Blalock-Taussig shunt versus the right ventricle to pulmonary artery shunt but was not associated with measured gastrointestinal outcomes.

Feeding complications in hypoplastic left heart syndrome after the Norwood procedure: a systematic review of the literature

Gastrointestinal and feeding complications after the Norwood procedure in infants with hypoplastic left heart syndrome increases morbidity and mortality. These problems are the result of intraoperative challenges, shunt-dependent physiology, and the absence of best-practice guidelines. In response, a systematic review of feeding-related complications and management strategies was performed. A literature search from 1950 to March 2010 identified 21 primary research articles and 4 reviews. Dysphagia, necrotizing enterocolitis (NEC), and poor nutritional status are significant feeding-related complications. Three studies directly compared the modified Blalock-Taussig shunt with the right ventricle-to-pulmonary artery conduit (RV-PA). Patients palliated with either shunt had impaired mesenteric blood flow. Mortality did not differ between shunt types. Three studies demonstrated improved outcomes, e.g., increased survival, decreased incidence of NEC, and decreased median time to recommended daily allowance of calories, with a postoperative feeding algorithm. Two studies showed increased survival between stage I and II surgical palliation after implementation of a home-monitoring system consisting of daily weight and systemic oxygen saturation measurements. The RV-PA shunt does not significantly alter mortality or increase mesenteric blood flow. A postoperative feeding algorithm and a home-monitoring system may improve outcomes and decrease average hospital length of stay (LOS). Additional studies are needed to determine which interventions, as part of a standardized protocol, improve survival and decrease complications.

Ischemia-reperfusion and neonatal intestinal injury

We review research relating ischemia/reperfusion to injury in the neonatal intestine. Epidemiologic evidence suggests that the most common form of necrotizing enterocolitis is not triggered by a primary hypoxic-ischemic event. Its late occurrence, lack of preceding ischemic events, and evidence for microbial and inflammatory processes preclude a major role for primary hypoxic ischemia as the sentinel pathogenic event. However, term infants, especially those with congenital heart disease who have development of intestinal necrosis, and those preterm infants with spontaneous intestinal perforations, are more likely to have intestinal ischemia as a primary component of their disease pathogenesis.

Necrotizing enterocolitis in neonates undergoing the hybrid approach to complex congenital heart disease

OBJECTIVE

To investigate the prevalence of necrotizing enterocolitis (NEC) in neonates undergoing the Stage I hybrid procedure for palliation of complex congenital heart disease (CHD). Neonates undergoing the Norwood surgery for hypoplastic left-heart syndrome have the highest risk for NEC of all CHD patients. The hybrid procedure is another palliative option for hypoplastic left-heart syndrome, but NEC in neonates undergoing this procedure has not been reported.

DESIGN

Retrospective chart review of 73 neonates who underwent the hybrid procedure for palliation of complex CHD. Demographic, perinatal, perioperative, clinical, and procedural data were collected. NEC was defined as modified Bell's Stage II and above.

SETTING

The cardiothoracic and neonatal intensive care units in a large free-standing children's hospital.

PATIENTS

All neonates who underwent the hybrid Stage I procedure for the palliation of complex CHD from April 2002 through April 2008.

MEASUREMENTS AND MAIN RESULTS

Seventy-three neonates were reviewed and 11.0% (eight of 73) developed NEC. Of the patients with NEC, 37.5% (three of eight) died and two patients required abdominal surgery. Earlier gestational age (< 37 wks), lower maximum dose of prostaglandin infusion, and unexpected readmission to the intensive care unit were statistically associated with NEC (p = .009, 0.02, and 0.04, respectively). No other demographic, perinatal, perioperative, clinical, or procedural variables were associated with the development of NEC in this patient population, including enteral feeding regimens, umbilical artery catheters, inotrope use, and average oxygen saturation and diastolic blood pressure.

CONCLUSIONS

The prevalence of NEC in patients undergoing the hybrid procedure is comparable to that reported for neonates undergoing the Norwood procedure. Earlier gestational age is a significant risk factor for NEC in patients who undergo the hybrid Stage I procedure. Multidisciplinary approaches to better understand abdominal complications and to develop feeding regimens in neonates undergoing the hybrid approach to complex CHD are needed to improve outcomes and decrease morbidities.

Frequency and indications for tracheostomy and gastrostomy after congenital heart surgery

Patients undergoing congenital heart surgery may occasionally require additional surgical procedures in the form of tracheostomy and gastrostomy. These procedures are often performed in an attempt to diminish hospital morbidity and length of stay. We reviewed the Web-based medical records of all patients undergoing congenital heart surgery at Miami Children's Hospital from February 2002 through August 2007. Patients who were deemed preterm and had undergone closure of a patent ductus arteriosis were eliminated. The records of all other patients were queried for the terms gastrostomy, g-tube, Nissan, fundal plication, tracheostomy, or tracheotomy. Patients' medical records in which these terms appeared in any portion were completely reviewed. There were 1660 congenital heart operations performed in the study period. There were 592 operations performed on patients whose age ranged from 1 month to 1 year and 441 neonatal operations. Mortality was 2%. Median postoperative stay was 8 days (range, 1-191 days), 12 days for neonates (range, 3-142 days), and 19 days for neonates undergoing RACHS-1 category 6 operations (range, 4-142 days). Tracheostomies were performed in four patients (0.2%). Gastrostomies were performed on eight patients (0.4%), representing 0.8% of patients <1 year of age, 1.4% of neonates, and 2.4% of patients undergoing RACHS-1 category 6 operations. The rate of patients undergoing either tracheostomy or gastrostomy after congenital heart surgery at our institution was quite low. Avoidance of either of these two procedures was achieved without increased morbidity or length of stay. The rate at which these procedures need to be performed may reflect the magnitude of the patients' lifetime trauma related to their underlying condition and acute and total surgical experiences.

The neonatal intestinal vasculature: contributing factors to necrotizing enterocolitis

Based on the demonstration of coagulation necrosis, it is clear that intestinal ischemia plays a role in the pathogenesis of necrotizing enterocolitis (NEC). Intestinal vascular resistance is determined by a dynamic balance between vasoconstrictive and vasodilatory inputs. In the newborn, this balance heavily favors vasodilation secondary to the copious production of endothelium-derived nitric oxide (NO), a circumstance which serves to ensure adequate blood flow and thus oxygen delivery to the rapidly growing intestine. Endothelial cell injury could shift this balance in favor of endothelin (ET)-1-mediated vasoconstriction, leading to intestinal ischemia and tissue injury. Evidence obtained from animal models and from human tissue collected from infants with NEC implicates NO and ET-1 dysregulation in the pathogenesis of NEC. Strategies focused on maintaining the delicate balance favoring vasodilation in the newborn intestinal circulation may prove to be useful in the prevention and treatment of NEC.

Feeding difficulties and growth delay in children with hypoplastic left heart syndrome versus d-transposition of the great arteries

The objective of this study was to identify the incidence of feeding difficulties in infants with hypoplastic left heart syndrome (HLHS) and d-transposition of the great arteries (d-TGA). Congenital heart disease is a risk factor for growth failure. The etiologies include poor caloric intake, inability to utilize calories effectively, and increased metabolic demands. The goals of our study were to (1) identify feeding difficulties in infants with HLHS and d-TGA and (2) assess their growth in the first year of life. We performed a chart review of 27 consecutive infants with HLHS and 26 with d-TGA. Descriptive statistics were generated for demographic and clinical variables within each group and are presented as means +/- standard deviations. HLHS and d-TGA groups were compared on time to achieving nutritional goals using the log rank test, on complication rate using the chi-square test, and on weight using the t-test. A significance level of 0.05 was used for all tests. Birth weight was similar for both the HLHS and d-TGA groups (3.19 +/- 0.69 vs 3.35 +/- 0.65 kg, respectively; p = 0.38). Infants with HLHS weighed less than those with d-TGA at l month (3.29 +/- 0.58 vs 3.70 +/- 0.60 kg, respectively; p = 0.021), 6 months (6.27 +/- 1.06 vs 7.31 +/- 1.02 kg, p = 0.003), and 12 months of age (8.40 +/- 1.11 vs 9.49 +/- 1.01 kg, p = 0.006). Time to achieving full caloric intake (at least 100 kcal/kg/day) for the HLHS group (24 +/- 11.9 days) was significantly longer than for the d-TGA group (12.0 +/- 11.2 days, p < 0.001). In addition, infants with HLHS had a higher incidence of feeding-related complications that those with d-TGA (48 vs 4%, respectively; p = 0.001). Compared to the d-TGA group, infants with HLHS weighed less at follow-up, took longer to reach nutritional goals, and had a much higher incidence of feeding-related complications.

Postoperative course in the cardiac intensive care unit following the first stage of Norwood reconstruction

The medical records of all patients born between 1 September, 2000, and 31 August, 2002, and undergoing the first stage of Norwood reconstruction, were retrospectively reviewed for details of the perioperative course. We found 99 consecutive patients who met the criterions for inclusion. Hospital mortality for the entire cohort was 15.2%, but was 7.3%, with 4 of 55 dying, in the setting of a "standard" risk profile, as opposed to 25.0% for those with a "high" risk profile, 11 of 44 patients dying in this group. Extracorporeal membrane oxygenation was utilized in 7 patients, with 6 deaths. Median postoperative length of stay in the hospital was 14 days, with a range from 2 to 85 days, and stay in the cardiac intensive care unit was 11 days, with a range from 2 to 85 days. Delayed sternal closure was performed in 18.2%, with a median of 1 day until closure, with a range from zero to 5 days. Excluding isolated delayed sternal closure, and cannulation and decannulation for extracorporeal support, 24 patients underwent 33 cardiothoracic reoperations, including exploration for bleeding in 12, diaphragmatic plication in 4; shunt revision in 4, and other procedures in 13. The median duration of total mechanical ventilation was 4.0 days, with a range from 0.7 to 80.5 days. Excluding those who died, the median total duration of mechanical ventilation was 3.8 days, with a range from 0.9 to 46.3 days. Reintubation for cardiorespiratory failure or upper airway obstruction was performed in 31 patients. Postoperative electroencephalographic and/or clinical seizures occurred in 13 patients, with 7 discharged on anti-convulsant medications. Postoperative renal failure, defined as a level of creatinine greater than 1.5 mg/dl, was present in 13 patients. Eleven had significant thrombocytopenia, with fewer than 20,000 platelets per microl, and injury to the vocal cords was identified in eight patients. Risk factors for longer length of stay included lower Apgar scores, preoperative intubation, early reoperations, reintubation and sepsis, but not weight at birth, genetic syndromes, the specific surgeon, or the duration of surgery. Although mortality rates after the first stage of reconstruction continue to fall, the course in the intensive care unit is remarkable for significant morbidity, especially involving the cardiac, pulmonary and central nervous systems. These patients utilize significant resources during the first hospitalization. Further studies are necessary to stratify the risks faced by patients with hypoplasia of the left heart in whom the first stage of Norwood reconstruction is planned, to determine methods to reduce perioperative morbidity, and to determine the long-term implications of short-term complications, such as diaphragmatic paresis, injury to the vocal cords, prolonged mechanical ventilation, and postoperative seizures.