What is Transposition of the Great Arteries?
Transposition of the great arteries (TGA) is a serious congenital defect in which the aorta and pulmonary artery swap positions. Normally the aorta arises from the left ventricle and the pulmonary artery from the right. In TGA these two great vessels are reversed — meaning oxygenated blood is sent back to the lungs rather than to the body's organs.
This creates two independent circulation loops. A newborn can survive only if there is communication between them — an open foramen ovale, VSD or PDA.
"The earlier this defect is identified, the greater the probability that the surgery will be radical and the child will not suffer repeat interventions. With late referrals, only haemodynamic corrections are possible — the defect itself is not eliminated. Time decides everything with this diagnosis."
Symptoms
TGA presents within the first hours after birth:
- Severe cyanosis — skin, lips and nails turn markedly blue
- Rapid breathing, shortness of breath
- Difficulty feeding
- Lethargy and weakness
- Heart murmur (not always present)
These symptoms require immediate medical attention. TGA is a critical condition for the newborn.
Why Early Referral Matters
In TGA, time is the most critical factor. The radical operation — the arterial switch procedure — is performed in the first 1–2 weeks of life and completely corrects the defect. The child recovers after a single operation.
With late presentation — after the first month — the left ventricle can no longer adapt to high systemic pressure. In these cases only haemodynamic correction is possible: blood flow is redirected, but the great arteries remain in their incorrect positions. Additional interventions will be needed in later years.
Important: TGA can be detected before birth by prenatal echocardiography. This allows time to prepare and plan delivery in a specialist centre. Foetal echo is mandatory when cardiac pathology is suspected.
The Arterial Switch Operation
The arterial switch is the definitive treatment for TGA. Under cardiopulmonary bypass the aorta and pulmonary artery are repositioned to their correct anatomical origins, and the coronary arteries are reimplanted.
Surgery is performed in the first 1–2 weeks of life. The result is an anatomically fully normal heart.
Treatment Outcomes
The success rate of the arterial switch operation in specialist centres exceeds 95%. Children make a full recovery, develop normally, and can participate in sport. Regular cardiac follow-up is required.
Can TGA be detected before birth?
Yes. Prenatal echocardiography can detect this defect from around 18–20 weeks of pregnancy. Early diagnosis gives parents time to prepare, and delivery is planned at a specialist centre.
What exactly does "late referral" mean?
After 3–4 weeks of life the left ventricle can no longer return to working under high pressure. The arterial switch operation is no longer possible. The alternative — Senning or Mustard procedures — redirects blood flow but does not correct the heart's anatomy. Further interventions will be required in subsequent years.
Do people live normally after the arterial switch?
Yes. Thousands of people worldwide who have had this operation live full lives, build families and careers. Regular cardiology follow-up is recommended, but for the vast majority quality of life is completely normal.
What should I do if TGA is diagnosed before birth?
Contact a specialist paediatric cardiologist and cardiac surgeon immediately. Delivery must be planned at a specialist centre. After birth, prostaglandin therapy is started immediately, and surgery is performed within 1–2 weeks.