Perioperative Mammillary Body Injury on MRI in Neonates with Severe Congenital Heart Disease.

BACKGROUND

Neonates with critical congenital heart disease (CCHD) are at risk for long-term cognitive impairments, including memory deficits. We aimed to assess the incidence and timing of mammillary body (MB) injury, critical memory structures, in neonates with CCHD and explore its association with cognitive outcome at 2 years of age.

METHODS

We included neonates who underwent surgery with cardiopulmonary bypass in the first 6 weeks of life. Pre- and postoperative cerebral magnetic resonance imaging were reviewed for MB injury, defined as signal change on T1-, T2-, or diffusion-weighted imaging, or atrophy. Cognitive outcomes at 2 years were measured using the Dutch Bayley Scales of Infant and Toddler Development, Third Edition.

RESULTS

A total of 96 neonates were included. MB injury was present in 5% preoperatively and 61% postoperatively (P < 0.001). It was not related to other acquired brain lesions. Preoperative MB injury occurred more frequently in neonates with younger postmenstrual age at birth (P = 0.002) and those who developed low cardiac output syndrome before surgery (P = 0.030). Similarly, new postoperative MB injury was associated with younger postmenstrual age at surgery (P = 0.002) as well as perioperative low cardiac output syndrome (P = 0.033). No significant differences in cognitive index scores emerged between children with neonatal MB injury and those without.

CONCLUSIONS

MB injury is frequent in neonatal CCHD, predominantly postoperatively, and is associated with low cardiac output syndrome and younger postmenstrual age. The relationship between neonatal MB injury and cognitive and memory outcomes later in life warrants further study.