Invited Commentary

Abstract

Surgical options for patients with dextroposed transposition of the great arteries and left ventricular outflow tract obstruction (LVOTO) are multiple: arterial switch operation (ASO), Rastelli procedure, Réparation à l'Etage Ventriculaire (REV) procedure (Lecompte operation), aortic translocation procedure (Bex-Nikaidoh operation) and en bloc rotation of the truncus arteriosus. The article by Kalfa and collaborators helps in defining the place of ASO in this group of patients [1Kalfa D.M. Lambert V. Baruteau A.E. et al.Arterial switch for transposition with left outflow tract obstruction: outcomes and risk analysis.Ann Thorac Surg. 2013; 95: 2097-2104Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar]. Careful preoperative evaluation of the mechanisms of LVOTO is critical to determining the optimal surgical option. LVOTO can be at the valvar or subvalvar level or both. It is likely that the valvar level is a major consideration in the decision-making process. In patients with a dysplastic and hypoplastic pulmonary valve, ASO is not an option. When an associated ventricular septal defect (VSD) is present, Rastelli or REV operation is usually indicated. The left ventricle is connected to the aortic orifice through the VSD; the VSD may be enlarged anteriorly if needed (classical Rastelli) or routinely by resection of the conal septum (REV). When a left ventricle-to aorta connection is deemed impossible or difficult (owing to absence of VSD or abnormal insertions of the tricuspid or mitral valve on the conal septum), the Bex-Nikaidoh operation (aortic translocation) provides a satisfactory solution. In all these nonanatomic repairs, the right ventricular outflow tract is reconstructed either with a valved conduit or using a valveless connection; this entails a significant risk of right ventricular outflow tract reoperation. At the other end of the clinical spectrum, the pulmonary valve is not dysplastic (although often bicuspid), the pulmonary annulus is normal-sized or mildly hypoplastic and LVOTO is predominantly subvalvar. ASO is indicated. This study confirms that satisfactory results are obtained when the pulmonary annulus is near normal (z-score > 1.8) and the LVOTO can be relieved effectively. To achieve adequate relief of LVOTO, associated surgery is often necessary (ie, resection of accessory mitral tissue or abnormal chordae, excision of subvalvar fibromuscular tissue); however, in a significant number of cases, restoring a systemic left ventricular pressure can relieve LVOTO without further surgery (ie, posterior deviation of the conal septum). The drawbacks of ASO in suboptimal indications cannot be underestimated: increased mortality rate (11% in the Kalfa series), risk of LVOT reoperation in multilevel and AV valve-related LVOTO (19%), and incidence of neoaortic regurgitation in patients undergoing subvalvar surgery through the neoaortic orifice (26%). Finally, there is a group of patients who are not included in this study. These patients have a dysplastic or hypoplastic pulmonary valve, which is not sufficient to serve as a neoaortic valve but can function satisfactorily as a pulmonary valve. The en bloc rotation of the truncus arteriosus provides an excellent solution that leaves the native arterial valves in their anatomic position above their respective ventricles [2Maier R. En-bloc rotation of the truncus arteriosus. A technique for complete anatomic repair of transposition of the great arteries/ventricular septal defect/left ventricular outflow tract obstruction or double outlet right ventricle/left ventricular outflow tract obstruction.Op Tech Thorac Cardiovasc Surg. 2009; 14: 45-54Abstract Full Text Full Text PDF Scopus (5) Google Scholar]. After harvesting of the truncus arteriosus, complex LVOTO (ie, atrioventricular valve–related lesions) can be relieved easily and extensively. In our experience, this procedure has provided encouraging midterm results in well-selected cases. Arterial Switch for Transposition With Left Outflow Tract Obstruction: Outcomes and Risk AnalysisThe Annals of Thoracic SurgeryVol. 95Issue 6PreviewThe long-term results and indications of the arterial switch operation (ASO) for transposition of the great arteries (TGA) and anatomic left ventricular outflow tract obstruction (LVOTO) remain undetermined. The aims of this study were to determine long-term outcomes and prognostic factors in this specific population. Full-Text PDF