Aortic arch interruption

Interrupted aortic arch (IAA), also known as aortic arch interruption, is a rare congenital heart defect in which there is a complete discontinuity (gap) between two segments of the aortic arch. This means that blood cannot flow normally from the heart to the lower body through the aorta. The condition is classified into three types based on the location of the interruption: Type A (interruption distal to the left subclavian artery), Type B (interruption between the left common carotid and left subclavian arteries, the most common form), and Type C (interruption between the innominate and left common carotid arteries, the rarest form). IAA is frequently associated with other cardiac anomalies, most notably a ventricular septal defect (VSD) and patent ductus arteriosus (PDA). The PDA is critical for survival in the neonatal period, as it provides the only pathway for blood to reach the lower body. Newborns with interrupted aortic arch typically present within the first days of life with signs of cardiovascular collapse as the ductus arteriosus begins to close. Symptoms include severe respiratory distress, poor feeding, weak or absent pulses in the lower extremities, metabolic acidosis, and signs of shock. Without treatment, the condition is fatal. Type B interruption is strongly associated with 22q11.2 deletion syndrome (DiGeorge syndrome), which may include additional features such as immune deficiency, hypocalcemia, and characteristic facial features. Immediate management involves administration of prostaglandin E1 (PGE1) to maintain ductal patency and stabilize the infant. Definitive treatment requires open-heart surgery, typically performed in the neonatal period, to reconstruct the aortic arch and repair associated cardiac defects such as VSD. Surgical outcomes have improved significantly over recent decades, and many patients survive into adulthood, though long-term follow-up is essential to monitor for complications such as re-coarctation, left ventricular outflow tract obstruction, and aortic valve abnormalities. Genetic counseling is recommended, particularly when 22q11.2 deletion is identified.

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