Abstract 19451: Preoperative Brain MRI Findings in d-Transposition of the Great Arteries and Relation to Timing of Diagnosis

Abstract

Introduction: Congenital heart disease is known to be associated with alterations in fetal cerebral blood flow and brain development. Instability in the fetal/neonatal periods may lead to injury. We sought to assess the prevalence of preoperative brain injury in neonates with d-transposition of the great arteries (d-TGA) and the relationship to prenatal/postnatal variables and outcomes. Methods: We performed a single center retrospective analysis of neonates with d-TGA who had preoperative brain MRI from 2009-2014. Patients with other cardiac and/or extracardiac anomalies were excluded. Prenatal/postnatal clinical variables were recorded and correlated to brain MRI findings. Results: A total of 45 neonates with d-TGA were identified of which 23 (51%) were diagnosed prenatally. The average gestational age was 38 weeks (range 33-41). All underwent an arterial switch procedure with 100% survival. Those diagnosed prenatally were more likely to be born within 5 miles of the tertiary pediatric center (96% vs. 5%, p<0.001), had lower incidence of hypoxia (lowest PaO2 25.3 vs 21.1, p=0.02), shorter time to cardiac intensive care unit admission (85 vs 1025 minutes, p=0.002), and shorter time to balloon atrial septostomy (295 vs 1456 minutes, p=0.007). Brain MRI was abnormal in 14 (31%); 9/23 (39%) with a prenatal and 5/22 (23%) with a postnatal diagnosis. The most common abnormality was small or punctate ischemic white matter lesions (N=14). Three patients had evidence of deep grey matter injury. Those with brain MRI abnormalities had a lower average gestational age (37 vs 39 weeks, p=0.02) and were less likely to have had a balloon atrial septostomy (79% vs 93%, p=0.03). Brain MRI findings were not associated with preoperative acidosis, hypoxia, need for inotropes, time to admission to cardiac intensive care unit, or surgical procedural variables. Conclusions: Neonates with d-TGA had similar incidence of preoperative brain injury by MRI whether diagnosed pre or postnatally. Brain injury was associated with lower gestational age and lack of balloon septostomy. Further work is needed to determine any association between prenatal diagnosis and type/severity of brain injury, as well as other in utero factors relating to brain development that may play a role.