Arterial switch with full-flow cardiopulmonary bypass and limited circulatory arrest: neurodevelopmental outcome

Abstract

Objectives: Neonatal cardiac surgery has been associated with unfavorable neurodevelopmental events. We investigated a patient cohort operated on predominantly with full-flow cardiopulmonary bypass (150 mL x kg(-1) x min(-1), alpha-stat, alpha-blockade, median arrest = 6 minutes, temperature of 22 degrees C) as the major support strategy for neonatal arterial switch operations (transposition of the great arteries and intact ventricular septum).

Methods: Seventy-four patients and "best-friend" control subjects were assessed 109 months (range, 48-166 months) postoperatively with general medical and neurologic evaluation, IQ testing, formal movement scores, and detailed parent-teacher behavioral-social reports. Fetal, neonatal, and perioperative data were collated.

Results: The prevalence of perioperative seizures was 6.8% (4/5 cases occurring preoperatively). The incidence of all perioperative neurologic abnormalities was 20%. Patients who had a neurologic event were (as a group) older at the time of operation and had a lower arterial blood pH before the operation. Selected perioperative factors (not related directly to cardiopulmonary bypass variables) predicted early (before discharge) neurologic outcome in a multivariate model. At late assessment, patients were more likely than control subjects to have a mild neurologic abnormality (P = 0.002). Full-scale IQ scores (Wechsler Preschool and Primary Scale of Intelligence and Wechsler Intelligence Scale for Children-Third Edition) were higher in control subjects (101.9 [SD = 13] vs 108.6 [SD = 12], P =.0007), with both groups having scores greater than the population-based test means. Full-scale IQ scores related most significantly to years of paternal education (beta = 1.51, P =.0078) but were also influenced by perioperative neurologic abnormalities, birth weight, and circulatory arrest time. Patients had higher motor impairment scores (Movement Assessment Battery) than control subjects (P =.0004). Parents (Achenbach Child Development Checklist) assigned higher total social-behavioral competence scores to control subjects (P =.05). Teachers (Achenbach Teacher Report Form) suggested that patients were more likely to be perceived as having various speech and expressive language problems, as well as minor behavioral problems.

Conclusion: With the perioperative strategies used, not all survivors can be considered (neurodevelopmentally) normal at late follow-up, although the risk of important impairment is low. Perioperative events might have long-term prognostic value. On the basis of this study and published data regarding other strategies, continued application of full-flow cardiopulmonary bypass is justified, with the proviso that further investigation is required.