End-Organ Saturation Differences in Early Neonatal Transition for Left- versus Right-Sided Congenital Heart Disease

Background: For neonates with congenital heart disease (CHD), left-sided (LL) and right-sided (RL) single ventricular physiologies (LL, hypoplastic left heart syndrome; RL, tricuspid atresia or pulmonary atresia with intact ventricular septum) may demonstrate distinct changes in tissue saturation in the first 72 h of life. Near-infrared spectroscopy (NIRS) can measure regional cerebral saturation (Csat) and renal saturation (Rsat) to clarify differences between LL and RL over time. Objectives: Our primary objective was to measure changes in Csat and Rsat in the first 72 h of life using NIRS between CHD infants with LL compared to RL. The secondary objective was to correlate NIRS values to an echocardiographic marker of perfusion. Method: Newborns with hypoplastic left heart syndrome, tricuspid atresia, and pulmonary atresia with intact ventricular septum from 2013 to 2016 underwent routine NIRS monitoring. Csat, Rsat, and systemic saturations (SpO2) in the first 72 h of life were retrospectively analyzed and the echocardiographic descending aorta velocity time integral (VTI) was measured. Mixed effects models compared differences over time between LL and RL. Results: The final cohort included 13 LL, 12 RL, and 4 controls. Csat decreased for RL compared to LL (p = 0.005), while Rsat decreased for both (p = 0.008). Over time, SpO2 increased for LL but decreased for RL (p = 0.046). Compared to the controls, infants with CHD had lower Csat, lower Rsat, and lower SpO2. The descending aorta VTI was correlated with Rsat (R2 = 0.24, p = 0.02). Conclusion: NIRS Csat measures were better preserved in LL compared to RL. Rsat decreased in both groups through time. The correlation between the descending aorta VTI and Rsat suggests an association between NIRS measures of renal saturation and renal perfusion.