Congenitally Corrected Transposition of the Great Arteries

Congenitally corrected transposition of the great arteries (CC-TGA) is an anatomically complex form of congenital heart disease which comprises a combination of atrio-ventricular (AV) and ventriculo-arterial (VA) discordance, or “double discordance.” Although there are multiple levels of anatomic aberrancies in CC-TGA, the effects of double discordance initially appear to cancel out as deoxygenated blood from the venous circulation can receive oxygen from the pulmonary vascular bed and is recirculated into the systemic circulation for tissue extraction. While this has led to adoption of the term “congenitally corrected” transposition, there is abundant evidence that the clinical course of this congenital heart defect often is far from correct. CC-TGA can occur in isolation but is often associated with other abnormalities in 80–90% of cases. The most frequent associated abnormalities include CC-TGA with ventricular septal defect (VSD) (60–80% of cases), CC-TGA with pulmonary outflow obstruction (50% of cases), and CC-TGA with anomalies of the left-sided tricuspid valve (TV) (90% of cases). Hence, symptomatic presentation of patients with CC-TGA is heavily dependent on the presence and severity of these additional lesions. Medical and surgical management also require individualized consideration and are affected by associated cardiac aberrancies. Surgical strategies for CC-TGA have evolved and continue to vary widely across institutions. This chapter will provide a comprehensive description of CC-TGA, its most commonly associated lesions, as well as the various potential clinical sequela. Medical and surgical considerations for this complex and heterogenous patient population will be explored in depth.