This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientifi statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish as well as human induced pluripotent stem cell–based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care–related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.
Today, most female children born with congenital heart disease will reach childbearing age. For many women with complex congenital heart disease, carrying a pregnancy carries a moderate to high risk for both the mother and her fetus. Many such women, however, do not have access to adult congenital heart disease tertiary centers with experienced reproductive programs. Therefore, it is important that all practitioners who will be managing these women have current information not only on preconception counseling and diagnostic evaluation to determine maternal and fetal risk but also on how to manage them once they are pregnant and when to refer them to a regional center with expertise in pregnancy management.
Background
Survivors of the Norwood procedure may suffer neurodevelopmental impairment. Clinical trials to improve outcomes have focused primarily on methods of vital organ support during cardiopulmonary bypass.
Methods
In the Single Ventricle Reconstruction trial of the Norwood procedure with modified Blalock-Taussig shunt vs. right-ventricle-to-pulmonary-artery shunt, 14-month neurodevelopmental outcome was assessed using the Psychomotor Development Index (PDI) and Mental Development Index (MDI) of the Bayley Scales of Infant Development®-II. We used multivariable regression to identify risk factors for adverse outcome.
Results
Among 373 transplant-free survivors, 321 (86%) returned at age 14.3±1.1 (mean±SD) months. Mean PDI (74±19) and MDI (89±18) scores were lower than normative means (each P<.001). Neither PDI or MDI score was associated with type of Norwood shunt. Independent predictors of lower PDI score (R2= 26%) were clinical center (P=.003), birth weight<2.5 kg (P=.023), longer Norwood hospitalization (P<.001), and more complications between Norwood procedure discharge and age 12 months (P<.001). Independent risk factors for lower MDI score (R2= 34%) included center (P<.001), birth weight<2.5 kg (P=.04), genetic syndrome/anomalies (P=.04), lower maternal education (P=.04), longer mechanical ventilation after the Norwood procedure (P<.001), and more complications after Norwood discharge to age 12 months (P<.001). We found no significant relationship of PDI or MDI score to, perfusion type, other aspects of vital organ support (e.g. hematocrit, pH strategy), or cardiac anatomy.
Conclusion
Neurodevelopmental impairment in Norwood survivors is more highly associated with innate patient factors and overall morbidity in the first year than with intraoperative management strategies. Improved outcomes are likely to require interventions that occur outside the operating room.
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