Updated: 12/4/2021

Transposition of Great Vessels

Review Topic
  • Snapshot
    • A neonatal boy is born to a 38-year-old mother with gestational diabetes. He seems to be tolerating feeds; however, in the first few days of life, his mother notices that his lips turn blue whenever he cries. It resolves when he stops crying. On physical exam, the physician notes central cyanosis while crying. The physician puts him in a knee-to-chest position, without any effect. Echocardiography is obtained, and he is found with a large ventricular septal defect and transposition of the great vessels.
  • Introduction
    • Clinical definition
      • a congenital heart defect in which the aorta leaves the right ventricle and the pulmonary trunk leaves the left ventricle, resulting in the complete separation of the systemic and pulmonary circulations
  • Etiology
    • Failure of neural crest cells to migrate
    • Pathogenesis
      • failure of the aorticopulmonary septum to spiral results in complete separation of the systemic and pulmonary circulations
      • infants survive only if a shunt between the two circulations exist to mix oxygenated blood into the systemic circulation
        • patent ductus arteriosus (PDA)
        • ventricular septal defect (VSD)
        • atrial septal defect (ASD)
        • patent foramen ovale (PFO)
    • Associated conditions
      • VSD
      • coarctation of the aorta
  • Epidemiology
    • Demographics
      • male > female
      • present at birth
      • most common cyanotic lesion presenting immediately after birth
    • Risk factors
      • maternal diabetes
      • maternal smoking
      • advanced maternal age
  • Presentation
    • Symptoms
      • early and progressive cyanosis that does not correct with oxygen
      • signs of heart failure
        • tachypnea
        • sweating
        • poor feeding
    • Physical exam
      • cardiac
        • loud and single S2 heart sound
        • may have a soft systolic ejection murmur
        • may have harsh holosystolic murmur if patients have VSD
      • central cyanosis
  • Imaging
    • Radiography
      • indication
        • for all patients
      • recommend views
        • chest
      • findings
        • cardiomegaly
        • egg-on-a-string appearance
          • narrowed mediastinum
    • Echocardiography
      • indication
        • performed as a diagnostic test
        • most specific test
      • findings
        • pulmonary trunk arising from the left ventricle
        • aorta arising from the right ventricle
  • Differential
    • Tetralogy of Fallot
      • distinguishing factor
        • tet spells (cyanosis) that are resolved when placed in knee-chest position
  • Diagnosis
    • Making the diagnosis
      • based on clinical presentation and echocardiography
      • in some cases, patients may be diagnosed prenatally with fetal echocardiography
  • Treatment
    • Medical
      • prostaglandin E1
        • indication
          • for all neonates
        • mechanism of action
          • maintains a patent ductus arteriosus for adequate lower extremity perfusion
    • Operative
      • balloon atrial septostomy (Rashkind procedure)
        • indication
          • for all patients
          • performed for temporary mixing prior to definitive surgical repair
      • arterial switch surgical repair
        • indication
          • for all patients as definitive treatment
          • commonly performed in the first month of life
  • Complications
    • Heart failure
    • Sudden cardiac death
  • Prognosis
    • Infants experience severe cyanosis and tachypnea as the ductus arteriosus closes in the newborn period
    • Patients with large VSDs may not present with severe cyanosis
      • they may only have cyanosis when the patient cries or feeds due to increased oxygen needs with activity
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