Predicting Newborn Outcomes in Fetal Transposition of the Great Arteries: A Collaborative Multi-center Prospective Study of the Fetal Heart Society

Lisa K Hornberger, MD; Shaine Morris, MD, MPH; and Mary Donofrio, MD
Amount Funded: $60,000

Transposition of great arteries (TGA) is one the most common severe heart defects in newborns. In the normal heart, the aorta (the largest artery of the body) arises from the lower left chamber (left ventricle) carrying oxygen-rich (red) blood from the lungs to the body; whereas the pulmonary artery arises from the right ventricle carrying oxygen-poor (blue) blood returning from the body to the lungs. In simple TGA the aorta rises from the right ventricle sending blue blood back to the body and the pulmonary artery arises from the left ventricle sending red blood back to the lungs. While this circulation is well-tolerated before birth, immediately after birth, these babies can have profoundly low oxygen levels, presenting blue and extremely sick within minutes to hours of their first breath. The procedure “balloon atrial septostomy (BAS),” which enlarges the hole between the upper chambers of the heart, the patent foramen ovale (PFO), can be life-saving as it improves the mixing of blue and red blood. Without knowledge of the presence of TGA, affected babies can die before being transported to a site where the BAS can be performed. Even if they are born in a hospital that can manage such babies, they can die or suffer serious brain damage related to low oxygen levels that may impact them life-long. While TGA has been increasingly diagnosed before birth which has led to some improvements in outcome, it is still not possible to consistently identify babies who will be very blue and unwell at birth and who will need an emergent BAS or other therapy to improve their oxygen levels. This is critically important to know, as children who will be the sickest are best served by a highly coordinated approach to delivery, including delivery at a cardiac center (possibly in the operating room/catheterization lab), Cesarean section, and immediate intervention. The overarching aim of the current multi-center Fetal Heart Society study is to define the best predictors before birth of worse oxygen levels at birth and greater compromise, examining traditional as well as novel fetal echo (ultrasound)-based measures. We aim to recruit at least 150 pregnant mothers carrying fetuses with TGA from 26 different fetal heart programs to investigate by fetal echocardiography (ultrasound of the fetal heart) anatomical and functional features that best predict lower oxygen levels at birth (blueness) and need for an emergency BAS. This knowledge would substantially enhance the outcomes of affected babies who can be delivered at the right place and time and with the right equipment and clinical team to stabilize the baby, and can allow families who will have a more stable baby at delivery to have a less disruptive delivery experience.