Anatomic Repair Including Hemi-Mustard in Congenitally Corrected Transposition of the Great Arteries: What We know and Still Need to Know

Congenitally corrected transposition of the great arteries (ccTGA) is a complex congenital heart defect characterized by both atrio-ventricular and ventriculo-arterial discordance, which results in a physiologically " normal " circulation. There are various anatomical and clinical combinations in this disease entity. The natural course of ccTGA depends largely on the presence of associated defects such as ventricular septal defects (VSDs), pulmonary stenosis or atresia, more appropriately referred to as left ventricular outflow tract (LVOT) obstruction, and tricuspid valve (TV) anomalies. Surgical option for the management of ccTGA The optimal surgical option for ccTGA remains controversial because, fundamentally, the options are dependent on the cardiac anatomy as well as the operating surgeon and the surgical team. The known surgical treatment strategies are as follows; 1) conventional repair, 2) anatomic repair, 3) single ventricle palliation (Fontan operation). The conventional repair is focused on addressing the associated lesions without correcting the discordant connections, which finally leaves the morphological right ventricle (RV) and TV to serve as the systemic circulation. These patients usually suffer from progressive RV failure and tricuspid regurgitation after repair. Biliciler-Denktas et al. 1) from the Mayo Clinic reported that overall survival after conventional repair was 77% at 5 years and 67% at 10 years, and late survival was adversely affected by prior operations, more severe preoperative functional class, and cardiac rhythm other than sinus. Hraska et al. 2) from the Boston Children's Hospital reported that the 1-and 15-year survivals after conventional repair were 84% and 61%, respectively, and those requiring TV replacement at any time during follow-up had a significantly worse outcome. These two reports drew a similar conclusion that long-term outcome of conventional repair is unsatisfactory and alternative surgical approaches should be considered to achieve better outcomes. Even with no associated lesions, the natural history of ccTGA is poor, with only 50% survival at 40 years. Therefore, ccTGA itself should be considered to be far from being 'corrected', and true correction, in terms of restoring the discordant connections has been achieved by anatomic repair. 3) The anatomic repair places the morphological left ventricle (LV) and mitral valve in the systemic circulation. Since Ilbawi et al. 4) first introduced the concept of anatomic repair, numerous reports have been published, showing its encouraging early-and intermediate-term results. Anatomic repair represents a group of procedures in which the atrio-ventricular discordance is 'corrected' by an atrial switch (Senning or Mustard), or hemi-Mustard, and ventriculo-arterial …