How Small Is Too Small? Decision-Making and Management of the Small Aortic Root in the Setting of Interrupted Aortic Arch.

Interrupted aortic arch is commonly associated with a posterior malalignment ventricular septal defect (VSD) and left ventricular outflow tract (LVOT) hypoplasia. Standard repair is carried out in the neonatal period and includes re-establishing arc continuity and VSD closure. Reintervention on the LVOT for obstruction is a common and an ongoing source of morbidity and mortality. A variety of preoperative echocardiographic measurements have been identified to identify patients at risk for developing LVOT obstruction but an aortic valve annulus dimension (mm) < patient's weight (kg) + 1 mm is a reasonable threshold to identify a patient at increased risk for future LVOT reintervention. Prophylactic direct approaches to prevent future LVOT obstruction include myectomy/myotomy and left-sided placement of the VSD patch but do not reliably prevent late LVOT obstruction. Patients amendable to a biventricular repair but with important LVOT hypoplasia are probably best served with a Yasui operation, either as a primary operation or staged with a Norwood procedure. In the case of complex redo operations, a Ross-Konno provides another valuable option for a durable repair. Though smaller preoperative LVOT structures predict the need for reoperation, careful preoperative planning may minimize the need for LVOT reintervention and improve long-term survival.