Glial Fibrillary Acid Protein and Cerebral Oxygenation in Neonates Undergoing Cardiac Surgery.

BACKGROUND: Neonates undergoing surgery for complex congenital heart disease are at risk of developmental impairment. Hypoxic-ischemic brain injury might be a contributing factor. We aimed to investigate the perioperative release of the astrocyte cytoskeleton component glial fibrillary acid protein and its relation to cerebral oxygenation.

METHODS: Serum glial fibrillary acid protein levels were measured before and 0, 12, 24, and 48 hours after surgery. Reference values were based on preoperative samples; concentrations above the 95th percentile were defined as elevated. Cerebral oxygenation was derived by near-infrared spectroscopy.

RESULTS: Thirty-six neonates undergoing 38 surgeries utilizing cardiopulmonary bypass were enrolled (complete data available for 35 procedures). Glial fibrillary acid protein was elevated after 18 surgeries (arterial switch: 7/12; Norwood: 5/15; others: 6/8; p = 0.144). Age at surgery was higher in cases with elevated serum levels (6 [4-7] vs. 4 [2-5] days, p = 0.009) and intraoperative cerebral oxygen saturation was lower (70 ± 10% vs. 77 ± 7%, p = 0.029). In cases with elevated postoperative glial fibrillary acid protein, preoperative cerebral oxygen saturation was lower for neonates undergoing the arterial switch operation (55 ± 9% vs. 64 ± 4%, p = 0.048) and age at surgery was higher for neonates with a Norwood procedure (7 [6-8] vs. 5 [4-6] days, p = 0.028).

CONCLUSIONS: Glial fibrillary acid protein was elevated after ∼50% of neonatal cardiac surgeries and was related to cerebral oxygenation and older age at surgery. The potential value as a biomarker for cerebral injury after neonatal cardiac surgery warrants further investigation; in particular, the association with neurodevelopmental outcome needs to be determined.