Abstract 13400: Patients Less Than or Equal to 2.5kg Have Higher Morbidity and Mortality After Norwood-sano Palliation

Introduction: In patients with single ventricle heart disease, prematurity and low weight at the Norwood operation are risk factors for mortality. Reports assessing peri-operative and long-term outcomes of Norwood palliation in patients ≤ 2.5kg are limited. Methods: All patients who underwent Norwood-Sano procedure between 2005-2020 were identified. Patients ≤ 2.5kg at the time of the Norwood operation (cases) were matched 1:3 with patients ≥ 3.0 kg (comparisons) for year of surgery and cardiac diagnosis. Demographic and peri-operative characteristics, survival to hospital discharge and 2-year neurodevelopmental outcomes were compared. Results: Twenty-seven cases (mean±SD weight 2.2±0.3 kg, mean age 15.6±14.1 days at surgery) and 81 comparisons (mean weight 3.5±0.4 kg, mean age 10.9±7.9 days at surgery) were identified. There was no statistically significant difference in the presence of chromosomal abnormalities (7.4% vs. 12.3%, p=0.485), prenatal diagnosis made (88.9% vs. 75.3%, p=0.141), or duration of cardiopulmonary bypass (140.7±65.6 vs. 121.3±42.3 min, p=0.068) between cases and comparisons, respectively. Cases had a longer time to post-operative lactate < 2 mmol/L (33.1±27.5 vs. 17.9±12.2 hours, p Conclusions: Patients ≤ 2.5kg at the time of Norwood-Sano have significantly higher post-operative morbidity and mortality up to 2-year follow-up, and worse 2-year neurodevelopmental motor outcomes. Additional studies are warranted to assess the outcome of alternative therapeutic options in this patient population.