Selective management strategy of interrupted aortic arch mitigates left ventricular outflow tract obstruction risk

Abstract

BackgroundLeft ventricular outflow tract obstruction (LVOTO) is an important problem after interrupted aortic arch (IAA) repair, especially when early reoperation is required during infancy. Several anatomic factors have been identified that increase LVOTO risk; surgical strategies such as concomitant resection of the conal septum or left ventricular outflow tract (LVOT) bypass (single-stage Yasui operation, or staged Norwood procedure, followed by the Rastelli procedure) have been proposed for such patients. MethodsFrom 2002 to 2013, a total of 77 neonates underwent IAA repair. Based on the presence of anatomic substrate for LVOTO, patients underwent standard IAA repair and ventricular septal defect closure (n = 53; 69%), concomitant conal resection (n = 7; 9%), or LVOT bypass (n = 17; 22%, staged in 14). We analyzed anatomic details that influence procedure choice, and explored reoperation risk and survival after repair. ResultsNeonates who had conal resection or LVOT bypass had significantly smaller aortic valve and subaortic areas, as well as a trend toward a higher prevalence of type B IAA, aberrant right subclavian artery, and bicuspid aortic valve. Freedom from LVOT reoperation was 96% and 80%, at 1 and 8 years, respectively, and was lower after conal resection (P = .008). Most LVOT reoperations (73%) were for discrete subaortic obstruction. Survival was 86% at 8 years, and was not related to procedure choice, whereas freedom from all-cause reoperation was 65% at 8 years, and was higher after standard repair (P = .029). ConclusionsCompared with published reports, this selective management strategy, which is customized to the degree of aortic valve and subaortic area narrowing, has mitigated and delayed LVOTO risk. With this tailored approach, most LVOT reoperations occur after infancy and are commonly for discrete subaortic obstruction. The effect of aortic valve and LVOT narrowing on increased LVOTO risk is neutralized with LVOT bypass procedures; however, it continues to be the highest after conal resection, suggesting the superiority of LVOT bypass, compared with enlargement in neonates who are at risk of developing LVOTO.