Neurodevelopmental outcome in hypoplastic left heart syndrome: Impact of perioperative cerebral tissue oxygenation of the Norwood procedure

Abstract

Objectives: Patients with hypoplastic left heart syndrome are at risk for neurodevelopmental impairment. Hypoxic-ischemic brain injury during neonatal treatment might be a relevant cause. We evaluated the association between cerebral oxygenation in the perioperative course of the Norwood procedure and neurodevelopmental outcome.

Methods: Cerebral tissue oxygen saturation (ScO2) was obtained by near-infrared spectroscopy for 24 hours before and 48 hours after surgery in 43 patients. Full-scale, verbal, and performance IQ scores were evaluated with the Wechsler Preschool and Primary Scale of Intelligence at a median of 4.5 years (range, 3.5-6.8 years). Cognitive functions were assessed with the German Kognitiver Entwicklungstest für das Kindergartenalter (KET-KID).

Results: Mean IQ scores and KET-KID percentile ranks were in the lower-normal range (full-scale IQ, 94 ± 11; verbal IQ, 97 ± 13; performance IQ, 93 ± 9; KET-KID global, 42 ± 27; verbal, 48 ± 29; nonverbal, 37 ± 23). Scores were below average (full scale IQ <85 or KET-KID <16th percentile) in 12 cases. Mean preoperative ScO2 was lower in patients scoring below average (56.8% ± 7.1% vs 61.7% ± 5.8%; P = .028) and was correlated with full-scale IQ (r = 0.495; P = .001), verbal IQ (r = 0.524; P = .001), and performance IQ (r = 0.386; P = .012) scores, and with global (r = 0.360; P = .018) and verbal (r = 0.395, P = .009) KET-KID scores. A relationship between IQ or KET-KID scores and postoperative ScO2 was not found. Gestational age, head circumference z-score, age at surgery, and postoperative length of stay were associated with IQ and KET-KID scores.

Conclusions: Neurodevelopmental outcome was in the lower-normal range. Along with innate patient factors, preoperative cerebral tissue oxygenation is likely an important determinant of cognitive development.

Keywords: hypoplastic left heart syndrome, developmental outcome, near-infrared spectroscopy.