Cerebral injury after neonatal cardiac surgery: Outcome at school age

Children born with a complex congenital heart defect, often need life-saving
cardiac surgery. As surgical techniques have improved in the past decades, even
the most complex defects are still eligible for correction. However, the more
complex, and thus longer surgeries, which are performed with the use of
cardiopulmonary bypass, entail a higher risk of cerebral injury.

Especially neonates born with an aortic arch obstruction, who undergo surgery
which includes cooling to a deep hypothermic temperature (18*C), are at risk of
primarily ischemic brain injury. We observed this in our recently published
study in which 37 neonates were imaged using MRI of the brain, and underwent
neurodevelopmental testing. Already before surgery, 50% of the neonates had
lesions on their cerebral MRI scan, and after surgery 75% of the cohort had new
injury. At 2 years of age, 2 of the 23 tested children (9%) had a
neurodevelopmental delay.

In the current study, we wish to assess the long-term consequences of complex
congenital heart disease. We aim to assess children at an age of 8 years, at
which an MRI scan can be expected to be successful without the need for
sedation. Also, as MRI techniques have become more sophisticated over the
years, one can now assess the connectivity of the brain, using techniques such
as diffusion tensor imaging (DTI) and functional MRI (fMRI). This allows us to
analyse brain networks, and how these networks are influenced or alteredby
cerebral injury.

We hypothesize that children who have evidence of brain injury at school age
have different network patterns than healthy children, and that this relates to
their neurodevelopmental outcome.

To gain insight in the cerebral consequences of neonatal cardiac surgery.

In this mono-centre, observation al study, children originally included in the
randomized controlled trial (RCT), comparing cardiopulmonary bypass techniques
during aortic arch reconstruction (protocol number 08-090/K), will be
approached for the current study. Therefore, this is a longitudinal study.

We will perform an MRI of the brain, by which MRI injury will be assessed both
using conventional MRI sequences, and connectivity techniques (i.e. DTI and
fMRI). We will compare the results to those of healthy children, included in
the Youth Cohort (Dept. of Psychiatry, METC 11/225), and children after
perinatal asfyxia (METC 14/529).

In this current observational study, the children will undergo an MRI of the
brain, which takes approximately 30 minutes. Sedative medication will not be
used, nor will intravenous contrast. Although not compulsory for participation,
the child will be offered a practice session in a *mock-MRI*, to reduce anxiety
during the scan. Nevertheless, if there is too much anxiety or restlessness
during scanning, the scan protocol will be shortened or stopped.

There are no health risks associated with the MRI scan itself. Therefore,
considerable collective expertise has been gained in MRI techniques and
associated practical issues in children (METC 01/229).

Performing brain imaging in children at this age with this neonatal condition
is important to understand why children with these conditions have
neurocognitive problems. Results of the study may aid patients to understand
some of the limitations in behaviour and/ or learning they may experience, in
turn offering possibilities for intervention. Additionally, this study may
contribute to the identification of prognostic parameters for outcome in
similar patient populations.