Ann Thorac Surg 2006;81:967
© 2006 The Society of Thoracic Surgeons
Original article: Cardiovascular
Invited commentary
J. William Gaynor, MD
a
,
Gil Wernovsky, MD
b
,
Robert Clancy, MD
c
a Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA 19104
b Pediatric Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104
c Neurology, Neurocardiac Research Group of The Cardiac Center, The Children's Hospital of Philadelphia, Philadelphia, PA 19104
(Email: gaynor{at}email.chop.edu; wernovsky{at}email.chop.edu; clancy{at}email.chop.edu).
Mortality after surgical repair of complex congenital heart defects in infancy has declined dramatically. As long-term survival continues to improve there has been increasing emphasis on other outcomes including exercise capacity, neurodevelopmental status, and quality of life. Hövels-Gürich and colleagues [1] should be congratulated for this study, which evaluates the neurodevelopmental outcomes and exercise capacity in 40 school-age children after infant repair of tetralogy of Fallot or ventricular septal defect. All patients were repaired using cardiopulmonary bypass with deep hypothermic circulatory arrest. The evaluation included neurologic function, motor function, intelligence, academic achievement, language skills, and exercise capacity. There was no difference in exercise capacity between the groups or compared with normal children. However the study suggests that children with preoperative hypoxemia were at higher risk for neurodevelopmental abnormalities compared with those who do not. Consistent with previous studies, the cohort had mild cognitive impairment with additional deficits in motor function and language. Motor dysfunction was more common in the tetralogy of Fallot group compared with the ventricular septal defect group.
This study provides confirmatory information concerning the neurodevelopmental sequelae in school-age children after infant cardiac surgery. The Boston Circulatory Arrest Study, which evaluated infants after the arterial switch operation for transposition of the great arteries, suggested that there is a distinctive neurodevelopmental signature after neonatal cardiac surgery consisting of mild cognitive impairment with decreased motor skills and language abnormalities [2]. Previous reports have suggested that the neurodevelopmental outcomes for children with tetralogy of Fallot and ventricular septal defect are possibly worse than those for transposition of the great arteries at 1 year of age [3]. In the current study of older children, the authors conclude that preoperative hypoxemia is a risk factor for worse neurodevelopmental dysfunction. However, the mean age at surgery was greater than 6 months and more than half the patients with tetralogy of Fallot presented with hypercyanotic spells. Repair at a younger age (eg, 2 to 3 months) may avoid the neurologic sequelae of a hypercyanotic spell, but it would need to be balanced against the risk of cardiopulmonary bypass on a more immature brain [4]. Although the use of deep hypothermic circulatory arrest for repair of congenital heart defects remains controversial, follow-up studies have suggested that long-term neurodevelopmental outcomes of relatively short periods of deep hypothermic circulatory arrest (< 40 to 45 minutes) are similar to those of continuous cardiopulmonary bypass [5]. In the current study, both groups underwent deep hypothermic circulatory arrest, so differences in intraoperative management are unlikely to explain the differences in neurodevelopmental outcome between the groups. There is increasing evidence that genetic polymorphisms that modulate the response to the inflammatory stimulus of cardiopulmonary bypass or modify neuronal repair after injury may be important determinants of central nervous system injury and long-term neuordevelopmental outcome [6]. These genetic factors may explain some of the inter-individual variations seen in the outcomes.
Survival of neonates and infants with congenital heart defects continues to improve. The results of this important study are encouraging as they demonstrate that the neurologic dysfunction in school-age children after infant repair of relatively simple defects is generally mild, and exercise capacity is maintained. However we cannot be lulled into complacency by these findings. It is of the utmost importance that we continue to evaluate the long-term outcomes of children with congenital heart defects into adulthood, to explore the mechanisms of the central nervous system injury, and to continuously assess modifiable risk factors such as cardiopulmonary bypass, deep hypothermic circulatory arrest, and perioperative care.
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References
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- Hövels-Gürich HH, Konrad K, Skorzenski D, et al. Long-term neurodevelopmental outcome and exercise capacity after corrective surgery for tetralogy of Fallot or ventricular septal defect in infancy Ann Thorac Surg 2006;81:958-967.[Abstract/Free Full Text]
- Bellinger DC, Wypij D, Kuban KC, et al. Developmental and neurological status of children at 4 years of age after heart surgery with hypothermic circulatory arrest or low-flow cardiopulmonary bypass Circulation 1999;100:526-532.[Abstract/Free Full Text]
- Bellinger DC, Wypij D, duPlessis AJ, et al. Developmental and neurologic effects of alpha-stat versus ph-stat strategies for deep hypothermic cardiopulmonary bypass in infants J Thorac Cardiovasc Surg 2001;121:374-383.[Medline]
- Galli KK, Zimmerman RA, Jarvik GP, et al. Periventricular leukomalacia is common after neonatal cardiac surgery J Thorac Cardiovasc Surg 2004;127:692-704.[Abstract/Free Full Text]
- Wypij D, Newburger JW, Rappaport LA, et al. The effect of duration of deep hypothermic circulatory arrest in infant heart surgery on late neurodevelopmentThe Boston Circulatory Arrest Trial. J Thorac Cardiovasc Surg 2003;126:1397-1403.[Abstract/Free Full Text]
- Gaynor JW, Gerdes M, Zachai EH, et al. Apolipoprotein E genotype and neurodevelopmental sequelae of infant cardiac surgery J Thorac Cardiovasc Surg 2003;126:1736-1745.[Abstract/Free Full Text]
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