Aortic Atresia or Complex Left Outflow Tract Obstruction in the Presence of a Ventricular Septal Defect

Abstract

Severe left outflow tract obstruction (LVOTO) is not always associated with hypoplastic left heart syndrome (HLHS). Aortic valvar atresia or complex LVOTO in the presence of a large ventricular septal defect (VSD) are a rare group of lesions that offer the possibility of biventricular repair. The Yasui procedure is the commonest surgical approach which can be performed as a primary neonatal correction or as a staged procedure with a Norwood followed by a subsequent Rastelli. This article reviews the surgical outcomes and decision-making process. Both strategies are reasonable with the trend toward staged procedure in the setting of the additional interrupted arch, with neonatal survival of > 90% in the modern era and excellent long-term survival. Re-intervention is mostly related to conduit revision and the need for re-operation for LVOTO is rare. Deciding between conventional repair and the Yasui in cases of LVOTO/VSD can be difficult and there are no uniform accepted criteria. In a typical neonate, an aortic annulus < 4.5 mm is generally the limit of acceptability for a conventional repair. In selected cases of LVOTO/VSD, an alternative to the Yasui is the Ross-Konno. Retrospective comparisons between the 2 techniques are difficult due to differing patient characteristics (especially associated with mitral valve disease) but the neonatal Ross has been associated with higher early mortality.

Which Phenotypes Should We Include in the Hypoplastic Left Heart Syndrome?

“…It is our opinion, therefore, that the evidence available from pathological archives dictates that an intact ventricular septum should now be added to the definition provided for both hypoplastic left heart syndrome and hypoplastic left heart complex. As was stated by Howell and colleagues in their contribution to the special issue, 9 “it was Maurice Lev in 1966 who noted that the presence of the VSD created a different clinical entity to that of aortic atresia associated with HLHS.” We would argue that the same argument holds sway for all the lesions that might now appropriately be grouped as belonging to the syndrome when the ventricular septum is intact. The integrity, or otherwise, of the ventricular septum impacts on the hemodynamics of any given feature, with further implications relating to ventricular interactions, development, genetics, the fate of the pulmonary vasculature, protocols for treatment, collection of data, and outcomes.…”

Defining the Spectrum of Hypoplastic Left Heart Syndrome (HLHS)

“…Of note, as listed above, aortic valvar atresia with a large VSD and a well-developed left ventricle is not considered to be HLHS. 11 The purpose of this commentary is to provide the rationale to support our conclusion that "Although HLHS + IVS and HLHS + VSD are different cardiac phenotypes, both of these lesions are part of the spectrum of HLHS. "…”