Factors Associated with Interstage Feeding Outcomes in Infants with Hypoplastic Left Heart Syndrome Undergoing Norwood Palliation: Preliminary Findings

Background: Children with congenital heart disease are at significant risk for feeding difficulty and failure to thrive due to a variety of reasons including increased metabolic demand, inadequate oral intake, swallowing dysfunction, malabsorption and genetic factors. Infants with HLHS and single ventricle (SV) variants have been shown to be particularly susceptible to feeding difficulties, prolonging hospital length of stay after Norwood palliation. The inability to feed orally during the Interstage period (the time between the first and second palliative repair) is associated with higher mortality, and caregivers have reported feeding-related stress during the Interstage period as well.

Our primary hypothesis is that infants with postnatally diagnosed HLHS have no significant difference in Interstage feeding outcomes as infants with a prenatal diagnosis. Our secondary hypothesis is that there is potential for progression in feeding route during the outpatient Interstage period.

Methods: Our study is a retrospective multi-center cohort study of patients with single ventricle physiology with data obtained from the National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC), a network of 60+ pediatric cardiology centers that maintains a national registry of outcome data. We are analyzing patients that underwent Stage 1 surgical palliation (Norwood), were discharged home and then underwent Stage 2 surgical palliation (Glenn). We are using standard statistical methods and an extra layer of machine learning derived predictive analytics.

Results: Patients (total n= 1750) were categorized into the three feeding groups – all oral (PO), exclusively tube fed (NG, NJ or GT) and mixed (oral with tube support). We evaluated the change in route of feeding over time and found that the majority of patients feeding orally at the first clinic visit were still feeding orally at their last clinic visit. However, there were substantial positive changes in the other groups, with more than 30% of tube-dependent patients developing oral skills by their last clinic visit. (Table 1, p<0.001). When comparing the route of feeding at Norwood discharge (Graph 1, p=0.476) and Glenn discharge (Graph 1, p=0.387), there was no significant difference in route of feeding based on prenatal versus postnatal diagnosis.

Conclusion: There is no significant difference in route of feeding based on prenatal versus postnatal diagnosis in infants with HLHS or SV variants undergoing Norwood. Infants have the potential for progression in feeding route between their first and last outpatient Interstage clinic visit. Identifying the centers with infants showing significant progressive improvement in oral feeding skills may provide insight into successful practice methods. A better understanding of peri-operative factors that influence Interstage feeding outcomes will help guide providers in minimizing modifiable risks for tube-dependence and predicting likelihood of requiring tube support.