pediatrics
Congenitally Corrected Transposition of the Great Arteries
Pathophysiology of CCTGA
In the more common Transposition of the Great Arteries (TGA) (dextro-transposition or d-TGA), the aorta arises directly from the right ventricle and the pulmonary artery arises from the left ventricle, resulting in independent, parallel pulmonary and systemic circulations; oxygenated blood cannot reach the body except through openings connecting the right and left sides (eg, patent foramen ovale, atrial or ventricular septal defects). This type of transposition results in immediate postnatal severe cyanosis and requires immediate intervention at birth and surgical correction within the first week of life. AO = aorta; LA = left atrium; LV = left ventricle; PA = pulmonary artery; RA = right atrium; RV = right ventricle. In congenitally corrected transposition (levo-transposition [l-TGA] CCTGA), the right atrium connects to a right-sided morphologic left ventricle (LV) and the left atrium connects to a left-sided morphologic right ventricle (RV). In almost all cases, the morphologic LV connects to the pulmonary artery and the morphologic RV connects to the aorta. The circulation is thus physiologically “corrected,” but clinical symptoms and adverse hemodynamic sequelae are almost always present. These sequelae result from the anomalies that frequently are associated with CCTGA or from having a morphologic right ventricle supporting the systemic circulation. The vast majority of patients with CCTGA have one or more of the following associated defects ( Pathophysiology references ): VSD (> 60%) Pulmonic stenosis (40%) Ebstein anomaly or other dysplasia of the left sided tricuspid valve (90%) Congenital or acquired AV block (progressive in 2% per year, 10 to 15% by adolescents and up to 30% in adults) Malposition with mesocardia or dextrocardia (20%) Progressive dysfunction of the systemic right ventricle (50% by 30 years of age) 1.Cui H, Hage A, Piekarski BL, et al: Management of Congenitally Corrected Transposition of the Great Arteries With Intact Ventricular Septum: Anatomic Repair or Palliative Treatment?Circ Cardiovasc Interv14(7):e010154, 2021. doi:10.1161/CIRCINTERVENTIONS.120.010154 2.Wallis GA, Debich-Spicer D, Anderson RH: Congenitally corrected transposition.Orphanet J Rare Dis6:22, 2011. doi:10.1186/1750-1172-6-22 