Congenitally Corrected Transposition of the Great Vessels
In congenitally corrected transposition of the great arteries (CCTGA), there is inversion of the ventricles and abnormal positioning of the aorta and pulmonary arteries. As a result, the right ventricle assumes the role of the high pressure systemic ventricle, instead of the low pressure pulmonary ventricle that is present in the normal heart. In some patients, this may lead to failure of the right ventricle, worsening function of the tricuspid valve, and congestive heart failure. In other patients, this abnormality is well tolerated and compatible with survival late into adulthood.
The majority of patients with congenitally corrected transposition of the great arteries also have other cardiac defects, such as a ventricular septal defect (VSD) and/or pulmonary stenosis. These additional abnormalities typically determine the patient’s course.
Patients who have a large VSD require early surgical closure. Those with both severe pulmonary stenosis and a VSD generally require surgery to close the VSD and relieve the obstruction between the ventricle and the pulmonary artery. In some cases, this will involve closure of the VSD and placement of a conduit from the ventricle to the pulmonary artery. This leaves the patient with a systemic right ventricle and a conduit which will typically develop obstruction over time.
An alternative but more complicated approach is to combine an atrial baffle (Senning) with a Rastelli repair. This has the advantage of restoring the left ventricle as the systemic ventricle. An occasional patient can have a well-balanced situation and may not require surgery for many years. Choosing between these various surgical options is complicated and requires a team of experienced cardiologists and congenital heart surgeons.
In the patients who have a systemic right ventricle and conduit, the long term issues in adults include:
- Function of the systemic right ventricle and the tricuspid valve
- Electrical abnormalities
- Assessment of the conduit for the presence of significant obstruction or regurgitation that may require additional interventions such as insertion of a catheter valve or surgical revision