Changing expectations for neurological outcomes after the neonatal arterial switch operation

Background: Expectations for outcomes after the neonatal arterial switch operation (ASO) continue to change. This cohort study describes neurodevelopmental outcomes at age 12 months after neonatal ASO, and analyzes both modifiable and nonmodifiable factors for association with adverse outcomes. Methods: Patients who underwent an ASO (n = 30) were enrolled in a prospective outcome study, with comprehensive clinical data collection during the first 12 months of life. Brain magnetic resonance imaging was done preoperatively and 7 days postoperatively, and the Bayley Scales of Infant Development III was performed at age 12 months. Results: Ten of 30 patients (33%) had preoperative magnetic resonance imaging injury; 13 of 30 patients (43%) had new postoperative magnetic resonance imaging injury. Twenty patients (67%) had Bayley Scales of Infant Development III: Cognitive Composite standard score mean was 104.8 ± 15.0, Language Composite standard score median was 90.0 (25th to 75th percentile, 83 to 94), and Motor Composite standard score mean was 92.3 ± 14.2. Best subsets multivariable analysis found associations between lower preoperative and intraoperative cerebral oxygen saturation, preoperative magnetic resonance imaging brain injury, total bypass time, and total midazolam dose and lower Bayley Scales of Infant Development III scores at age 12 months. Conclusions: At 12 months after ASO, neurodevelopmental outcome means were within normal population ranges. The new associations reported in this study between potentially modifiable perioperative factors and outcomes require investigations in larger patient cohorts. Beyond survival, which was 100% in this cohort, factors influencing quality of life including neurodevelopmental outcomes should be routinely investigated in studies of ASO patients.