Methods: A total of 170 consecutive patients (96 males, 74 females; median age 12 months; range, 1 to 192 months) who underwent surgical repair of tetralogy of Fallot between January 2015 and April 2018 were retrospectively reviewed. A mechanical ventilation duration of >24 h, an intensive care unit stay of >3 days, and a hospital stay of >7 days were considered as prolonged. Unplanned reoperation, complete heart block requiring a permanent pacemaker implantation, renal failure, diaphragmatic paralysis, neurological deficit, sudden circulatory arrest, need for extracorporeal membrane oxygenation, and death were considered as major adverse events.

Results: The median time to hospital discharge was 8.0 (range, 5.0 to 40.0) days. Higher preoperative hematocrit levels prolonged the length of hospital stay (odds ratio: 1.12, 95% confidence interval 1.1-1.2, p<0.001). A total of 28 major adverse events were observed in 17 patients (10%). Lower pulmonary artery annulus Z-score (odds ratio: 0.5, 95% confidence interval 0.3-0.9, p=0.01) and residual ventricular septal defects (odds ratio: 54.6, 95% confidence interval 1.6-1,874.2, p=0.03) were found to increase mortality. Residual ventricular septal defect was also a risk factor for major adverse events (odds ratio: 12.4, 95% confidence interval 1.5-99.9, p=0.02).

Conclusion: Preoperative and operative factors such as high preoperative hematocrit, low preoperative oxygen saturation, low pulmonary annulus Z-score, Down syndrome, residual ventricular septal defects, and the use transannular patch were found to be associated with prolonged length of hospital stay, prolonged mechanical ventilation, prolonged intensive care unit stay, and increased development of major adverse events.