Surgical outcomes in pediatric patients with trisomy 21 undergoing congenital heart disease repair: A retrospective cohort analysis

Children with trisomy 21 (T21) frequently present with congenital heart disease (CHD), particularly complete atrioventricular canal (CAVC) and ventricular septal defect (VSD). Although historically considered a high-risk population for cardiac surgery, contemporary outcomes may be more closely related to surgical complexity and postoperative complications than to genetic diagnosis alone. To determine whether trisomy 21 independently predicts mortality after congenital heart disease repair and to identify modifiable postoperative risk factors in patients undergoing CAVC or VSD correction. This retrospective cohort study included 1886 cardiac surgeries performed in patients younger than 18 years between 2018 and 2024 at a tertiary referral center. Among these, 197 (10.4%) patients had trisomy 21. A subgroup analysis was conducted in RACHS-1 category 3 patients undergoing CAVC or VSD repair. Clinical characteristics and postoperative outcomes were compared between trisomy 21 and non-trisomy 21 patients, as well as between survivors and non-survivors. Multivariable logistic regression analysis was used to identify independent predictors of in-hospital mortality. Patients with trisomy 21 were younger and had lower surgical weight, with CAVC repair predominating. Postoperative morbidity and mortality were similar between trisomy 21 and non-trisomy 21 patients in both CAVC and VSD subgroups. In univariate analysis, elevated creatinine, increased lactate, low cardiac output syndrome, and sepsis were associated with mortality. In multivariable analysis, postoperative sepsis remained independently associated with mortality (OR 26.1; 95% CI 1.14–593.1; p = 0.041). In the VSD subgroup, early postoperative vasoactive-inotropic score was also associated with mortality. Conclusion: Trisomy 21 was not independently associated with mortality after congenital heart disease repair when surgical complexity was controlled. Postoperative sepsis was the strongest modifiable predictor of death, highlighting the importance of infection-prevention strategies and early postoperative management. • Trisomy 21 is not an independent risk factor for mortality after congenital heart surgery when surgical complexity is controlled, including in both CAVC and VSD repairs. • Sepsis was the only independent predictor of mortality in multivariable analysis, reinforcing infection as the most actionable perioperative target. • In the VSD subgroup, higher early postoperative inotropic score (VIS) was associated with increased mortality, highlighting the prognostic value of early hemodynamic instability. • Renal dysfunction, elevated lactate, and low cardiac output were linked to mortality in univariate analyses, but their effects were attenuated after adjusting for sepsis. • Clinical strategies should emphasize infection control, early hemodynamic support, and renal protection to optimize outcomes in children with T21 undergoing CHD repair.