Background New intraparenchymal brain injury on MRI is observed in 36–73% of neonates after cardiac surgery with cardiopulmonary bypass (CPB). Brain immaturity in this population is common. We performed brain magnetic resonance imaging (MRI) before and after neonatal cardiac surgery, using a high flow CPB protocol, hypothesizing that MRI brain injury would be associated with brain immaturity. Methods CPB protocol included 150 ml/kg/min flows, pH stat management, hematocrit >30%, and high flow antegrade cerebral perfusion. Regional brain oxygen saturation (rSO2) was monitored, with a treatment protocol for rSO2 <50%. Brain MRI, consisting of T1, T2, and diffusion weighted imaging, and MR spectroscopy were performed preoperatively, 7 days postoperatively, and at age 3–6 months. Results Twenty-four of 67 patients (36%) had new postoperative white matter injury (WMI), infarction, or hemorrhage, and 16% had new WMI. Associations with preoperative brain injury included low brain maturity score (p=0.002). Postoperative WMI was associated with single ventricle (SV) diagnosis (p=0.02), preoperative WMI (p<0.001) and low brain maturity score (p=0.05). Low brain maturity score was also associated with more severe postoperative brain injury (p=0.01). Forty-five patients had a 3rd scan, with a 27% incidence of new minor lesions, but 58% of previous lesions had partially or completely resolved. Conclusions We observed a significant incidence of both pre- and postoperative MRI abnormality, and an association with brain immaturity. Many lesions resolved in the first 6 months after surgery. Timing of delivery and surgery with bypass could affect the risk of brain injury.

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Summary Background Adverse neurodevelopmental outcomes are observed in up to 50% of infants after complex cardiac surgery. We sought to determine the association of perioperative anesthetic exposure with neurodevelopmental outcomes at age 12 months in neonates undergoing complex cardiac surgery and to determine the effect of brain injury determined by magnetic resonance imaging (MRI). Methods Retrospective cohort study of neonates undergoing complex cardiac surgery who had preoperative and 7-day postoperative brain MRI and 12-month neurodevelopmental testing with Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Doses of volatile anesthetics (VAA), benzodiazepines, and opioids were determined during the first 12 months of life. Results From a database of 97 infants, 59 met inclusion criteria. Mean ± sd composite standard scores were as follows: cognitive = 102.1 ± 13.3, language = 87.8 ± 12.5, and motor = 89.6 ± 14.1. After forward stepwise multivariable analysis, new postoperative MRI injury (P = 0.039) and higher VAA exposure (P = 0.028) were associated with lower cognitive scores. ICU length of stay (independent of brain injury) was associated with lower performance on all categories of the Bayley-III (P < 0.02). Conclusions After adjustment for multiple relevant covariates, we demonstrated an association between VAA exposure, brain injury, ICU length of stay, and lower neurodevelopmental outcome scores at 12 months of age. These findings support the need for further studies to identify potential modifiable factors in the perioperative care of neonates with CHD to improve neurodevelopmental outcomes.