EXPLANATION


Interrupted aortic arch (IAA) has an incidence of 1% of all congenital heart disease. It is classified into the following subtypes: 1) Type A (interruption distal to left subclavian artery); 2) Type B (interruption between left common carotid and left subclavian arteries); and 3) Type C (interruption between the innominate and left common carotid arteries). IAA is commonly associated with other congenital cardiac anomalies, including ventricular septal defect (VSD), which may contribute to left-ventricular outflow tract obstruction (LVOTO), as well as aortic annular hypoplasia, bicuspid aortic valve, and left ventricular (LV) muscle bundles. Type B IAA is commonly associated with a posterior malalignment VSD and an aberrant right subclavian artery. The posterior malalignment VSD can contribute to LVOTO with deviation of the conal septum. Neonates born with IAA typically remain asymptomatic until the ductus arteriosus closes, resulting in decreased lower body perfusion and, eventually, congestive heart failure and cardiogenic shock.


There are several surgical options available for the repair of IAA. In contemporary practice, primary complete neonatal repair has become standard of care. In children without LVOTO, repair typically consists of aortic arch repair with VSD closure. In low-birthweight or premature children, as well as those with contra-indications to CPB, palliative options include pulmonary artery banding along with either PDA stenting in the catheterization laboratory or off-bypass arch repair via thoracotomy. However, in the setting of significant LVOTO, management remains challenging with technically difficult procedures and a high rate of reintervention. Surgical options for this group of patients include the following: (1) aortic arch repair, VSD closure, and conal muscle resection; (2) initial neonatal Norwood or hybrid palliation with staged, biventricular repair in later infancy or (3) a neonatal Ross-Konno. In some patients with severe LVOTO, these procedures have a high probability of significant residual LVOTO, and an alternative approach for consideration is the Yasui procedure. It was first published in 1987 and consists of a Damus-Kaye-Stansel anastomois, baffled VSD closure that incorporates the native pulmonary valve, and a right ventricle to pulmonary artery conduit.


Greene et al. reported a single institution’s experience with the Yasui procedure at Boston Children’s Hospital, including 25 cases over 32 years. They reported a survival rate of 91% at 5 years; freedom from LVOT reintervention was 91% and freedom from RV-PA conduit reintervention was 52%. All patients had normal biventricular function. The authors concluded that the Yasui procedure compared favorably to the Staged single ventricle palliative pathway and the Ross-Konno procedure in terms of mortality and LVOT reintervention. Furthermore, patients who underwent the Yasui procedure did not require a greater number of reinterventions overall.


A multicenter study by Luo et al. analyzed outcomes in 150 neonates with IAA. They found that patients undergoing a Ross-Konno or a Yasui procedure had a lower risk of LVOT reintervention compared to standard arch repair, especially when combined with conal resection. Mortality after the Yasui procedure was seven percent, but most of those children had undergone a two-stage Yasui, with an interstage period characterized by single-ventricle physiology with a shunt. Interestingly, the mortality rate in children undergoing a Ross-Konno procedure was 0%. The authors attributed this mortality rate to patient selection, as children with IAA and LVOTO are more likely to have normal LV and mitral valve size and function as compared to patients with critical aortic stenosis and hypoplastic LV. Children who underwent IAA repair with VSD closure without conal resection had similar rates of LVOT reintervention as those with the Yasui procedure, but the authors noted that those children were less likely to have severe LVOTO. While most centers favor a single-stage neonatal repair whenever possible, the hybrid procedure, consisting of bilateral PA banding and ductal stenting, has been gaining traction. This approach is typically reserved for high-risk neonates, including those with prematurity, low birth weight, genetic disorders, extra-cardiac malformations, or clinical conditions such as sepsis, necrotizing enterocolitis, or intracranial hemorrhage. Conversely, some centers successfully use the hybrid approach in the absence of the listed risk factors.


The correct answer among those choices is B, the Yasui procedure, consisting of a complete repair and relief of LVOTO. Aortic arch repair with VSD closure remains the standard operation for IAA with a VSD, but is likely to require reintervention, especially in children with pre-existing LVOTO. The patient described in the stem also has severe LVOTO and would likely require conal muscle resection in addition to aortic arch repair and VSD closure. PA banding with off-bypass aortic arch repair is typically reserved for children with high-risk features or contraindications to cardiopulmonary bypass, which are not present in the patient in the stem. It is important to note that IAA remains a heterogeneous disease, and management requires multidisciplinary planning tailored to each patient and each surgical program’s expertise.


REFERENCES


LaPar DJ, Baird CW. Surgical Considerations in Interrupted Aortic Arch. Semin Cardiothorac Vasc Anesth. 2018;22(3):278-284. doi:10.1177/1089253218776664


Greene CL, Scully B, Staffa SJ, et al. The Yasui operation: A single institutional experience over 30 years. JTCVS Open. 2023;15:361-367. Published 2023 Jul 18. doi:10.1016/j.xjon.2023.06.019


Luo S, Schoof PH, Hickey E, et al. The Fate of the Left Ventricular Outflow Tract Following Interrupted Aortic Arch Repair. World J Pediatr Congenit Heart Surg. 2024;15(5):562-570. doi:10.1177/21501351241236742


Alsoufi B. Hybrid First-stage Palliation and Other Strategies to Achieve Biventricular Repair in High-Risk Neonates With Complex Heart Anomalies and Aortic Arch Obstruction. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2023;26:40-49. doi:10.1053/j.pcsu.2022.12.009


Yasui H, Kado H, Nakano E et al. Primary repair of interrupted aortic arch and severe aortic stenosis in neonates. J Thorac Cardiovasc Surg. 1987; 93:539-545.