DEVELOPMENTAL AND NEUROLOGIC STATUS OF CHILDREN AFTER HEART-SURGERY WITH HYPOTHERMIC CIRCULATORY ARREST OR LOW-FLOW CARDIOPULMONARY BYPASS

Background. Deep hypothermia with either total circulatory arrest or low-flow cardiopulmonary bypass is used to support vital organs during heart surgery in infants. We compared the developmental and neurologic sequelae of these two strategies one year after surgery. Methods. Infants with D-transposition of the great arteries who underwent an arterial-switch operation were randomly assigned to a method of support consisting predominantly of circulatory arrest or a method consisting predominantly of low-flow bypass. Developmental and neurologic evaluations and magnetic resonance imaging (MRI) were performed at one year of age. Results. Of the 171 patients enrolled in the study, 155 were evaluated. After adjustment for the presence or absence of a ventricular septal defect, the infants assigned to circulatory arrest, as compared with those assigned to low-flow bypass, had a lower mean score on the Psychomotor Development Index of the Bayley Scales of Infant Development (a 6.5-point deficit, P=0.01) and a higher proportion had scores less than or equal to 80 (i.e., 2 SD or more below the population mean) (27 percent vs. 12 percent, P=0.02). The score on the Psychomotor Development Index was inversely related to the duration of circulatory arrest (P=0.02). The risk of neurologic abnormalities increased with the duration of circulatory arrest (P=0.04). The method of support was not associated with the prevalence of abnormalities on MRI scans of the brain, scores on the Mental Development Index of the Bayley Scale, or scores on a test of visual-recognition memory. Perioperative electroencephalographic seizure activity was associated with lower scores on the Psychomotor Development Index (P=0.002) and an increased likelihood of abnormalities on MRI scans of the brain (P<0.001). Conclusions. Heart surgery performed with circulatory arrest as the predominant support strategy is associated with a higher risk of delayed motor development and neurologic abnormalities at the age of one year than is surgery with low-flow bypass as the predominant support strategy.