The association between cardiac physiology, acquired brain injury, and postnatal brain growth in critical congenital heart disease

Objective: To assess the trajectory of perioperative brain growth in relationship to cardiac diagnosis and acquired brain injuries. Methods: This was a cohort study of term neonates with hypoplastic left heart syndrome (HLHS) and d-transposition of the great arteries (d-TGA). Subjects underwent magnetic resonance imaging of the brain pre- and postoperatively to determine the severity of brain injury and total and regional brain volumes by the use of automated morphometry. Comparisons were made by cardiac lesion and injury status. Results: A total of 79 subjects were included (49, d-TGA; 30, HLHS). Subjects with HLHS had more postoperative brain injury (55.6% vs 30.4%, P = .03) and more severe brain injury (moderate-to-severe white matter [WM] injury, P = .01). Total and regional perioperative brain growth was not different by brain injury status (either pre- or postoperative). However, subjects with moderate-to-severe WM injury had a slower rate of brain growth in WM and gray matter compared with those with no injury. Subjects with HLHS had a slower rate of growth globally and in WM and deep gray matter as compared with d-TGA (total brain volume: 12 cm(3)/wk vs 7 cm(3); WM: 2.1 cm(3)/wk vs 0.6 cm(3); deep gray matter: 1.5 cm(3)/wk vs 0.7 cm 3; P<.001), after we adjusted for gestational age at scan and the presence of brain injury. This difference remained after excluding subjects with moderate-to-severe WM injury. Conclusions: Neonates with HLHS have a slower rate of global and regional brain growth compared with d-TGA, likely related to inherent physiologic differences postoperatively. These findings demonstrate the complex interplay between cardiac lesion, brain injury, and brain growth.