Fetal and Postnatal Effects of Hypoxia on Neuro Outcome in Congenital Heart Disease

Lay Summary: The STHS grant has supported our research to study the fetal and postnatal effects hypoxia has on the brain in children with congenital heart disease (CHD). Funding directly supported development of the brain MRI program for neonates with CHD. The program has allowed our group to perform detailed brain imaging of newborns with CHD before and in some cases after their surgery to identify patterns of brain immaturity or findings of brain injury that are likely to have occurred in the womb from altered blood flow. As part of the study, overall, 139 newborns have undergone brain oxygenation monitoring using a non-invasive device placed on the forehead in the intensive care unit. Eleven of these patients had also been evaluated as fetuses. Twenty-two had a brain MRI as part of the STHS grant with 20 receiving preoperative imaging and 17 additional post-operative imaging. Neurodevelopmental testing was performed at 6, 15 and/or 21 months in 16; the rest are awaiting assessment.

The preliminary results of our study have shown that many fetuses with CHD do have evidence for abnormal cerebral blood flow as documented by fetal ultrasound. In addition, many newborns with CHD also have evidence for both altered brain development and/or findings suggestive of brain injury even before surgery suggesting an in-utero cause. Abnormalities in fetal blood flow and abnormalities in brain oxygen levels have not yet been found to correlate with brain findings on MRI given the small number assessed thus far, however the project is ongoing.
Our preliminary results have shown that babies with lower brain oxygen levels in the operating room coming off the bypass machine or in the first 24 hours after surgery were more likely to die or have neurodevelopmental problems. This information is important in that it gives us something to potentially treat to improve the outcome for kids with CHD.

In summary, our study has confirmed that there are critical time points during the fetal, intraoperative, and postoperative periods that may impact both survival and neurodevelopmental outcome children with CHD. Our study has shown that brain oxygen monitoring during surgery and in the postoperative period may identify those at risk for brain injury and poor neurodevelopmental outcome. Future research will be initiated to develop medical care strategies to improve brain oxygen levels in the postoperative period with the ultimate goal being to improve outcomes for children with CHD.