Genetic Determinants of Congenital Heart Disease Outcomes

Overview

The purpose of this study is to examine the role of genetic variation in the oxidative stress response on critical perioperative and short-term outcomes after neonatal heart surgery. The goals will be to determine 1) if the oxidative stress pathway is an important one for therapeutic intervention in neonates with severe congenital heart defects and 2) if variants in the oxidative response pathway can be used to identify patients at increased risk for adverse outcomes.

For physicians caring for children with congenital cardiac defects, perhaps the greatest challenge is to improve the survival and functional outcomes of patients with severe defects requiring surgical repair or palliation in the first month of life. These cardiac defects can be associated with 5 year mortality rates of up to 30% with significant disabilities in many of the survivors. As with every medical condition, patient outcomes depend on the complex interaction of the disease process, the medical and surgical interventions to treat the disease, and the inherent capacity of the patient to respond to both the disease and its treatment. For patients with severe cardiac defects, the greatest risk for morbidity and mortality occurs during and shortly after their neonatal surgical repair. During surgery to repair severe cardiac defects, the body is cooled and the heart is stopped. In many cases, blood flow to the vital organs is interrupted or restricted for a significant period of time while the aortic arch is reconstructed. This process places profound stress on the patient's capacity to tolerate these insults without sustaining irreversible injury to tissues such as the heart, brain, and kidneys. That there is such a wide range of outcomes after this surgery, even between patients with similar clinical features, suggests that there are important individual differences in patients' abilities to respond to this stress that is determined by differences in their genetic traits. The importance of the interaction between the controlled trauma of the surgical environment and a patient's genetic background in determining patient outcomes has led to the new discipline of "peri-operative genomics." In this study, we will examine the contribution of gene-environment interactions to perioperative and short-term outcomes in neonates with severe congenital cardiac defects.