Early Developmental Outcome in Children With Hypoplastic Left Heart Syndrome and Related Anomalies: The Single Ventricle Reconstruction Trial

Study Questions:

What is the early developmental outcome of infants with hypoplastic left heart syndrome undergoing the Norwood procedure with modified Blalock-Taussig shunt and right-ventricle-to-pulmonary-artery shunt?


In this prespecified secondary study of the Single Ventricle Reconstruction (SVR) trial, neurodevelopmental outcomes were assessed at 14 months of age. The Psychomotor Development Index (PDI) and Mental Developmental Index (MDI) of the Bayley Scales of Infant Development-II were used.


A total of 321 patients underwent developmental assessment at age 14.3 ± 1.1 (mean ± standard deviation [SD]) months. Mean PDI (74 ± 19) and MDI (89 ± 18) scores were lower than normative means (p < 0.001). There was no difference in developmental outcome between shunt types. Independent predictors of lower PDI score included clinical center (p = 0.003), birth weight <2.5 kg (p = 0.023), longer Norwood hospitalization (p < 0.001), and more complications between Norwood procedure discharge and age 12 months (p < 0.001). Independent risk factors for lower MDI score included center (p < 0.001), birth weight <2.5 kg (p = 0.04), genetic syndrome/anomalies (p = 0.04), lower maternal education (p = 0.04), longer mechanical ventilation after the Norwood procedure (p < 0.001), and more complications between Norwood discharge and age 12 months (p < 0.001). No relationship was seen between developmental outcome and perfusion type, intraoperative hematocrit or pH management strategies, or cardiac anatomy.


Neurodevelopmental impairment is common in survivors of the Norwood procedure. Impairment is most related to patient factors and Norwood hospital course, as opposed to operative factors such as shunt type and intraoperative management studies.


This secondary trial of the SVR study assessed neurodevelopmental outcomes of survivors of the Norwood procedure. The results are discouraging both in the frequency of abnormal neurodevelopmental outcomes, as well as the lack of improvement as compared with earlier reports. No difference was seen based on shunt type, or bypass technique (regional cerebral perfusion or deep hypothermic circulatory arrest). There was a center-specific difference in neurodevelopmental outcomes, which was extensively explored as the data were analyzed. The cause for this is unclear, but may be related to differences in testing techniques at different centers, or differing postoperative ICU monitoring and management strategies. The study highlights the need to avoid elective deliveries prior to 30 weeks’ gestation when possible, optimizing cerebral protection perioperatively, and providing appropriate developmental support after discharge.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and CHD and Pediatrics, Congenital Heart Disease, CHD and Pediatrics and Interventions, CHD and Pediatrics and Quality Improvement, Interventions and Structural Heart Disease

Keywords: Survivors, Birth Weight, Norwood Procedures, Infant, Blalock-Taussig Procedure, Hypoplastic Left Heart Syndrome, Risk Factors

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