Brain metabolite concentrations in neonates with congenital heart disease before and after cardiac surgery

The purpose of this study was to compare brain metabolite concentrations between healthy and CHD neonates before and after cardiac surgery. Healthy term newborns and neonates with CHD were recruited prospectively. T₂-weighted brain images and MRS data were acquired in the cerebellum, right frontal lobe and basal ganglia. Clinical data were extracted from the medical record. Spectra were modeled using Osprey. General linear model and repeated measures ANOVA were performed to compare metabolite measurements among different groups. All comparisons were adjusted for gestational age and sex. MRS data were obtained in 57 controls and 64 with CHD neonates. Of those, 29 CHD newborns underwent both preoperative and postoperative scans. The most common CHD diagnoses were TGA (27%), HLHS (17%) and TOF (17%). Fifty percent of CHD were Class I lesion and 19% were Class IV. General linear model indicated that CSF-corrected tNAA, a measure of neurodevelopment, was significantly higher (p < 0.05) in the basal ganglia and right frontal lobe of healthy controls compared to preoperative and postoperative CHD respectively. Repeated measures ANOVA on longitudinal data reported significantly higher (p < 0.05) CSF-corrected tNAA in the cerebellum and basal ganglia of postoperative CHD; higher (p < 0.05) tCr in the right frontal lobe and basal ganglia of postoperative CHD and lower (p < 0.05) mI in the basal ganglia of postoperative CHD. There is a trend of increased (p ≤ 0.10) GABA+ in the cerebellum and basal ganglia of postoperative CHD. Findings suggested that impaired neurodevelopment was associated with critical CHD. Paired-wise comparisons show a slow but promising recovery with improved hemodynamics, energy reserve, regulation of brain activity and neuronal migration to the developing brain after cardiac surgery.