Does Down syndrome affect the long-term results of complete atrioventricular septal defect when the defect is repaired during the first year of life?

Background: Down syndrome is known to affect the natural history of complete atrioventricular septal defect. We analyzed whether Down syndrome affect the long-term results of complete atrioventricular septal defect when the defect is repaired during the first year of life. Methods: Repairs of complete atrioventricular septal defect were performed in 64 infants. Thirty-four infants were associated with Down syndrome, while the other 30 were non-Down patients. Results: Complete follow-up rate was 95% with mean follow-up period of 99±47 months (maximum 169 months) in Down patients and 80±64 months (maximum 213 months) in non-Down patients. There was one operative death in each group (mortality rate of 2.9% in Down patients and 3.3% in non-Down patients), and three patients died at the late phase (one in Down patients and two in non-Down patients). Five patients underwent re-operation due to postoperative left atrioventricular valve regurgitation (one in Down patients and four in non-Down patients). Freedom from re-operation for left atrioventricular valve regurgitation and actuarial survival rate at 13 years were 96±4 and 94±4% in Down patients and 85±7 and 90±5% in non-Down patients (not significantly different). Conclusions: Down syndrome does not affect the long-term results of complete atrioventricular septal defect when the defect is repaired during the first year of life.