Anomalous aortic origin of a coronary artery (AAOCA) is a rare congenital abnormality. AAOCA is associated with an increased risk of decreased blood flow to the heart tissue (called ischemia) and sudden death in otherwise healthy children and young adults. The risk of sudden death is greatest during or just after exercise.
Children’s Hospital researchers hypothesize that there is a decreased amount of blood flow to the region of the heart that is supplied by the anomalous coronary artery, caused by a narrowing at the opening of the coronary artery. To compensate for this narrowing, the portion of the vessel farther away from the opening is maximally or near-maximally enlarged (dilated) at rest.
During exercise, further coronary artery dilation is necessary to provide enough blood flow to the exercising heart muscle. Children with AAOCA may experience ischemia and sudden death, usually with exercise, because the already-dilated anomalous vessel cannot open further during exercise.
Understanding the cause of ischemia in AAOCA
Julie Brothers, MD, and colleagues conducted a study using adenosine magnetic resonance imaging (MRI) to help better understand the cause of ischemia in AAOCA. With better knowledge of which children are at more risk for ischemia, treatment can be better tailored to each individual child’s needs. This study was made possible by the American Heart Association and the Cardiac Center at The Children’s Hospital of Philadelphia.