Aorta – coarctation

Aorta – coarctation

Coarctation, with VSD
Four chamber view shows a muscular VSD and right atrial and ventricular enlargement. Colour flow studies reveal a left to right shunt through the VSD and flow to the pulmonary artery. An aortic stenosis is revealed by the white jet of colour. The pulmonary artery drains to the descending aorta via the dilated ductus arteriosus.
Double inlet ventricle
Both atrioventricular valves drain to a single ventricular chamber of left ventricular morphology. The aorta arises from an anterosuperior rudimentary right ventricle which is not well seen in this example. The aorta arises anterior to the pulmonary artery and is hypoplastic suggestive of an associated coarctation.

Description

Tricuspid dysplasia can be difficult to distinguish from Ebstein’s malformation, in fact the two overlap each other in terms of anatomical findings. The differentiation is not important. The displaced tricuspid valve cusps can be difficult to find in a severe case of Ebstein’s malformation and may therefore be mistaken for an unguarded orifice. However, in this condition, there is gross tricuspid regurgitation with hepatic congestion. If the left ventricle is very small and compressed by the right atrium it may be mistaken for a hypoplastic left heart, although this diagnosis should be reserved for cases of mitral atresia. The dilated right atrium has been mistaken for an intrathoracic cyst but blood flow within the atrial chamber should distinguish the two.

Diagnosis

In fetal life, the first clue to the diagnosis is asymmetry of the four chamber view, with the right ventricle dilated relative to the left. The left atrium, left ventricle and ascending aorta are slightly small for the gestational age. The pulmonary artery/aortic ratio is increased above normal and this and the hypoplasia of the transverse arch are more reliable predictors of this malformation than the relative ventricular sizes. The interatrial shunt is often reversed to become left to right. The transverse arch is narrowed in the horizontal views, especially in comparison with the arterial duct which will appear ‘fat’. It is unusual to see a discrete shelf in the posterior arch, which typifies this lesion in postnatal life. Associated cardiac lesions which are common include VSD and aortic stenosis. As the pregnancy advances, the left heart can become progressively hypoplastic, such that this can develop into a form of hypoplastic left heart syndrome.

Differential Diagnosis

Other causes of right heart dominance should be excluded. An increase in the RV/LV ratio can be normal in late gestation, after about 30 weeks, but the other findings will not be present. Disproportion is always abnormal in early pregnancy. Cardiac causes of an increase in RV size include total anomalous pulmonary venous drainage and tricuspid incompetence.

Sonographic Features

RV larger than LV.

Left to right inter-atrial shunt.

PA much larger than Ao.

Narrow transverse arch, ‘fat’ duct Discrete narrowing of the arch before the ductal connection (rarely identifiable).

Associated Syndromes

  • 45 
  • X (Turner) 
  • Diabetes
  • Familial coarctation of aorta
  • Fetal Hydantoin
  • Fetal valproate
  • Trisomy 9 (mosaic)

References

  1. Anderson RH, McCartney FJ, Shinebourne EA, Tynan M (Eds)In: Paediatric Cardiology Churchill Livingstone: Edinburgh, p1087-1123
  2. Allan LD, Sharland GK, Milburn A, Lockhart SM, Groves AMM, Anderson RH, Cook AC, Fagg NLK Prospective diagnosis of 1,006 consecutive cases of congenital heart disease in the fetus J Am Coll Cardiol 23:1452-8
  3. Allan LD, Sharland G, Cook A Aortic interruption and coarctation In: Color Atlas of Fetal Cardiology Mosby-Wolfe: London, p123-127
  4. Gersony WMIn: Heart Disease in Infants, Children and AdolescentsAdams FH, Emmanouilides GC, Riemenschneider TA (Eds) Williams and Wilkins: Baltimore, p243-255
  5. Allan LD, Chita SK, Anderson RH, Fagg N, Crawford DC, Tynan MJ Coarctation of the aorta in prenatal life: an echocardiographic, anatomical and functional study Br Heart J 59:356-360
  6. Sharland GK, Chan K, Allan LD Coarctation of the aorta: difficulties in prenatal diagnosis Br Heart J 71:70-75
  7. Hornberger LK, Sahn DJ, Kleinman CS, Copel J, Silverman NH Antenatal diagnosis of coarctation of the aorta: a multicenter experience J Am Coll Cardiol 23:417-23
  8. Hornberger LK, Weintraub RG, Pesonen E, Murillo-Olivas A, Simpson IA, Sahn C, Hagen-Ansert S, Sahn DJ Echocardiographic study of the morphology and growth of the aortic arch in the human fetus: observations related to the prenatal diagnosis of coarctation Circulation 86:741-7
  9. Lacro RV, Jones KL, Benirschke K Coarctation of the aorta in Turner syndrome: a pathologic study of fetuses with nuchal cystic hygromas, hydrops fetalis, and female genitalia Pediatrics 81:445-51