P2A051: Predictors of Cardiac Arrest and Mortality Among Neonates with Hypoplastic Left Heart Syndrome in the United States

Background: Hypoplastic left heart syndrome (HLHS) is a type of congenital heart disease that results in the underdevelopment of the left-sided structures of the heart, including the mitral valve, left ventricle, aortic valve, ascending aorta, and aortic arch. HLHS comprises 3 % of all congenital heart diseases. Although rare, a diagnosis of HLHS is responsible for 23% of all cardiac deaths in the first week of life.

Methods: Neonates with a diagnosis of hypoplastic left heart syndrome were recruited from the 2016-2020 National Inpatient Sample(NIS). The impact of various patient characteristics and comorbidities on events of cardiac arrest and mortality was also analyzed via multivariable logistic regression models.

Results: There were 7670 cases of hypoplastic left heart syndrome among neonates in the United States between 2016-2020. Among them, 60.0% were Male, 46.0% were White, and 14.3% were Black. Medicaid was the primary insurance for the majority of patients (52.2%). The most common comorbidity was atrial septal defect (ASD) at 45.3%; less common were - 15.8% preterm or with extreme immaturity, 4.6% small for gestational age, 1.0% post-term, 8.4% had some forms of chromosomal abnormalities, 18.2% were diagnosed with ventricular septal defect (VSD), and 0.3% had Tetralogy of Fallot (TOF). Around 16.4% of patients were admitted on a weekend. During their hospitalization, 2.6% of the patients (200 cases) reported an event of cardiac arrest. Female patients (aOR 1.511, 95% CI 1.129-2.023,p < 0.01) had higher odds of reporting an event of cardiac arrest, while the patients with preterm or extreme immaturity (aOR 0.441, 95% CI 0.259-0.752, p< 0.01), Black (aOR 0.434, 95% CI 0.248-0.758, p< 0.01), and patients admitted on weekends (aOR 0.422, 95% CI 0.248-0.718, p< 0.01) had lower odds.
Unfortunately, 16.1% of newborns did not survive hospitalization, and a higher incidence of mortality was reported among preterm or newborns with extreme immaturity (aOR 2.532, 95% CI 2.184-2.934, p< 0.01), chromosomal abnormalities (aOR 3.092, 95% CI 2.564-3.727, p< 0.01), while patients with ASD (aOR 0.687, 95% CI 0.596-0.791, p< 0.01), races other than White or Black (aOR 0.806, 95% CI 0.700-0.927, p< 0.01) (vs White) had lower odds.

Conclusion: Cardiac arrest is more common in female patients. Mortality in HLHS is higher among preterms and patients with chromosomal abnormalities.