Subjects were enrolled between April 1988 and February 1992. Eligibility criteria and trial methods for the earlier evaluations were previously described.7 (link)–10 (link) Admission criteria included a diagnosis of d-TGA with intact ventricular septum (IVS) or ventricular septal defect (VSD), scheduled repair by three months of age, and coronary-artery anatomy suitable for the ASO. Exclusion criteria were birth weight <2.5 kg, a recognizable syndrome of congenital anomalies, an associated extra-cardiac anomaly of greater than minor severity, previous cardiac surgery, or associated cardiovascular anomalies requiring aortic arch reconstruction or additional open surgical procedures.
Infants were randomly assigned to a predominant support strategy of DHCA or LFBP during hypothermic cardiopulmonary bypass using an alpha-stat pH strategy and crystalloid hemodilution to a hematocrit of approximately 20%. Ultrafiltration was not utilized. Postoperative management typically included the use of continuous infusions of neuromuscular blockade and high-dose Fentanyl for analgesia, with a median duration of mechanical ventilation of 4 days.12 (link) Randomization was stratified by septal status (IVS, VSD) and surgeon. This study was approved by the Institutional Review Board and conducted in accordance with institutional guidelines. Parents of adolescents provided informed consent, and adolescents provided assent.
We recruited a referent group of adolescents for the MRI studies because there is no nationally representative standardization sample for brain MRIs. This group was also used as referents for test scores for which national norms are unavailable. Criteria for the referent group were adapted from those used in the NIH MRI study of normal brain development.13 (link) Because the goal of that study is to provide reference ranges for brain development, children with known risk factors for brain disorders are excluded (e.g., intra-uterine exposures to toxicants, history of closed head injury with loss of consciousness, history of a language disorder or Axis 1 psychiatric disorder, first degree relative with a lifetime history of an Axis 1 psychiatric disorder, abnormality on neurological examination). We also excluded subjects with disorders that would prevent completion of the assessments (e.g., pacemaker, metal implants), other forms of congenital heart disease requiring surgical correction, or primary language other than English.
Infants were randomly assigned to a predominant support strategy of DHCA or LFBP during hypothermic cardiopulmonary bypass using an alpha-stat pH strategy and crystalloid hemodilution to a hematocrit of approximately 20%. Ultrafiltration was not utilized. Postoperative management typically included the use of continuous infusions of neuromuscular blockade and high-dose Fentanyl for analgesia, with a median duration of mechanical ventilation of 4 days.12 (link) Randomization was stratified by septal status (IVS, VSD) and surgeon. This study was approved by the Institutional Review Board and conducted in accordance with institutional guidelines. Parents of adolescents provided informed consent, and adolescents provided assent.
We recruited a referent group of adolescents for the MRI studies because there is no nationally representative standardization sample for brain MRIs. This group was also used as referents for test scores for which national norms are unavailable. Criteria for the referent group were adapted from those used in the NIH MRI study of normal brain development.13 (link) Because the goal of that study is to provide reference ranges for brain development, children with known risk factors for brain disorders are excluded (e.g., intra-uterine exposures to toxicants, history of closed head injury with loss of consciousness, history of a language disorder or Axis 1 psychiatric disorder, first degree relative with a lifetime history of an Axis 1 psychiatric disorder, abnormality on neurological examination). We also excluded subjects with disorders that would prevent completion of the assessments (e.g., pacemaker, metal implants), other forms of congenital heart disease requiring surgical correction, or primary language other than English.
