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

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).

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.

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.

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.