Hypothermia vs normothermia in neonatal arterial switch operation – Clinical outcomes and myocardial preservation

Cardiopulmonary bypass (CPB) management during pediatric cardiac surgery represents a critical aspect of optimizing patient outcomes. Historically, the arterial switch operation (ASO) for transposition of the great arteries (TGA) was performed using hypothermic CPB, but growing evidence suggests potential benefits of normothermic approaches. This study aimed to compare clinical outcomes and myocardial preservation between hypothermic (HT-CPB) and normothermic (NT-CPB) temperature management strategies during neonatal ASO, with special emphasis on cardiomyocyte injury assessed through tissue-specific cell-free DNA (cfDNA). This retrospective observational study analyzed data from 27 neonates (12 HT-CPB, 15 NT-CPB) who underwent ASO between July 2017 and December 2018. Clinical parameters were compared between groups, including CPB duration, cross-clamp time, postoperative cardiac biomarkers, and cfDNA trajectories as markers of cellular damage. The NT-CPB group demonstrated significantly shorter CPB (71.93 ± 28.49 vs. 116.00 ± 20.15 min, p < 0.001) and cross-clamp times (54.73 ± 32.24 vs. 96.92 ± 21.66 min, p < 0.001). Maximal lactate (51.00 ± 18.11 vs. 65.33 ± 12.43 mg/dL, p = 0.028) and Troponin-I levels (10.57 ± 2.83 vs. 15.37 ± 1.55 ng/dL, p < 0.001) were significantly lower in the NT-CPB group in oppose to higher incidence of AKI. While total cfDNA levels were comparable between groups at most time points, cardiac cfDNA was significantly lower in the NT-CPB group at 24 h post-surgery ( p = 0.002). Normothermia during neonatal ASO was associated with shorter operative times, lower metabolic stress, and reduced myocardial injury compared to hypothermia. These findings support the non-inferiority of normothermia as a viable and potentially beneficial temperature management strategy for neonatal ASO, offering comparable safety with improved hemodynamic and myocardial preservation outcomes. • Tissue specific cfDNA is efficient for quantitative assessment of cell death. • Normothermia during CPB is associated with shorter operative times. • Normothermia during CPB is associated with lower metabolic stress. • Normothermia during CPB is associated with reduced myocardial injury.