Transposition of the Great Vessels


  • Congenital abnormality where the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle, resulting in circulation of deoxygenated blood after the closure of the ductus arteriosus at around 48 hours old
  • Occurs in around 0.2-0.3/1000 live births; slightly more common in males
  • It is often associated with other congenital heart defects e.g. ventricular septal defects (which can mask signs of cyanosis i


  • It can now be diagnosed antenatally at USS althoug many present post-natally with peripheral and central cyanosis within the first few hours of life +/- signs of heart failure (usually later in patients with a VSD which compensates slightly by allowing mixing of oxygenated and deoxygenated blood)
    • hypoxia (low oxygen saturations)


  • Echocardiography is the gold standard test
  • Lactate is a good prognostic indicator


  • Initial symptomatic treatment includes prostaglandins to try a keep the ductus arteriosus open (allowing mixture of oxygenated and deoxygenated blood)
    • Oxygen therapy
  • Intermediate balloon septoplasty
    • Most infants have this percutaneous procedure which effectively creates a VSD if there is not already one present (again for the same reason, to allow mixing blood)
  • Corrective surgery
    • Arterial switch procedure


  • Hypoxic brain injury can occur in these babies if surgery is performed too late
  • Surgery will often fully correct the problem, however ~3% will suffer complications, which may be acute-onset e.g. brain damage/renal failure, lung infection, pleural effusion/pericardial effusion; or late onset e.g. pulmonary hypertension, pulmonary and aortic valve disease

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