In transposition of the great arteries (TGA), the major blood vessels coming out the right and left sides of the heart are switched. Normally, blood without oxygen is pumped to the lungs and blood with oxygen is pumped to the body. With TGA, this pattern is reversed such that blood without oxygen is pumped to the body and blood with oxygen is pumped to the lungs.
TGA occurs in approximately 2 to 4 of every 10,000 live births.
Although TGA is only rarely associated with additional abnormalities, it is important to investigate with ultrasound for other abnormalities that may be present. When TGA is suspected, further evaluation includes a specialized evaluation of the fetal heart (“fetal echocardiogram”) to confirm the finding. Genetic counseling and testing may be recommended. Prenatal consultations with pediatric cardiology, pediatric cardiothoracic surgery, and neonatology specialists are recommended to discuss the prognosis and management after birth. Prenatal care will be managed by a Maternal-Fetal Medicine specialist, an obstetrician with special training and expertise in high-risk pregnancies. Pregnancies complicated by TGA require a specially timed delivery coordinated between obstetrical and neonatology specialists.
Newborns will be evaluated and cared for by a team involving pediatric cardiology and neonatology specialists. Cases involving severely low oxygen levels at birth may require an immediate procedure (balloon atrial septostomy) to allow mixture of blood between the two sides of the heart. All newborns with TGA require corrective surgery, which typically occurs within the first week of life. Long-term outcomes for people with corrected TGA appear to be excellent, however there is some risk for neurocognitive delays.