Outcomes of atrioventricular septal defects with and without down syndrome: Analysis of the national inpatient database

Background: Controversial data exist about the impact of Down syndrome on outcomes after surgical repair of atrioventricular septal defect. Aims: (A) assess trends and outcomes of atrioventricular septal defect with and without Down syndrome and (B) determine risk factors associated with adverse outcomes after atrioventricular septal defect repair. Methods: We queried The National Inpatient Sample using International Classification of Disease codes for patients with atrioventricular septal defect < 1 year of age from 2000 to 2018. Patients' characteristics, co-morbidities, mortality, and healthcare utilisation were evaluated by comparing those with versus without Down syndrome. Results: In total, 2,318,706 patients with CHD were examined; of them, 61,101 (2.6%) had atrioventricular septal defect. The incidence of hospitalisation in infants with atrioventricular septal defect ranged from 4.5 to 7.5% of all infants hospitalised with CHD per year. A total of 33,453 (54.7%) patients were associated with Down syndrome. Double outlet right ventricle, coarctation of the aorta, and tetralogy of Fallot were the most commonly associated with CHD in 6.9, 5.7, and 4.3% of patients, respectively. Overall atrioventricular septal defect mortality was 6.3%. Multivariate analysis revealed that prematurity, low birth weight, pulmonary hypertension, and heart block were associated with mortality. Down syndrome was associated with a higher incidence of pulmonary hypertension (4.3 versus 2.8%, p < 0.001), less arrhythmia (6.6 versus 11.2%, p < 0.001), shorter duration for mechanical ventilation, shorter hospital stay, and less perioperative mortality (2.4 versus 11.1%, p < 0.001). Conclusion: Trends in atrioventricular septal defect hospitalisation had been stable over time. Perioperative mortality in atrioventricular septal defect was associated with prematurity, low birth weight, pulmonary hypertension, heart block, acute kidney injury, and septicaemia. Down syndrome was present in more than half of atrioventricular septal defect patients and was associated with a higher incidence of pulmonary hypertension but less arrhythmia, lower mortality, shorter hospital stay, and less resource utilisation.