Interrupted aortic arch

Interrupted aortic arch (IAA) is an uncommon congenital cardiovascular anomaly where there is a separation between the ascending and descending aorta. It can either be complete or connected by a remnant fibrous band. An accompanying large ventricular septal defect (VSD) and/or patent ductus arteriosus (PDA) is frequently present.

It may account for ~1.5% of congenital cardiac anomalies. 

Faulty embryological development of the aortic arch (thought to occur during the 5th to 7th week of intrauterine life).

Classification

According to the Celoria-Patton classification, IAA can be classified into three types according to the location of the anomaly:

  • type A: second most common, the interruption occurs distal to the left subclavian arterial origin 
  • type B: most common (>50%), the break occurs between the left common carotid and left subclavian arterial origins
  • type C: rare, interruption occurs proximal to the left common carotid arterial origin

Each type is divided into three subtypes 7:

  • subtype 1: normal subclavian artery
  • subtype 2: aberrant subclavian artery
  • subtype 3: isolated subclavian artery that arises from the ductus arteriosus.
Associations
Plain radiograph

Plain film features are often non-specific 3:

  • the aortic knuckle may be absent
  • may show cardiomegaly
Antenatal ultrasound/Echocardiography

The right ventricle may appear a lot larger than the left, although this is a non-specific finding. The ascending aorta may also appear more vertical than usual. These modalities may not allow differentiation of IAA from severe aortic coarctation with a hypoplastic arch 9.

CT/CTA

Allows visualisation of the interrupted aortic arch and associated anomalies. 

MRI/MRA
  • non-visualisation of the portion of interruption
  • great vessels may show a "V" configuration on coronal imaging 2

If uncorrected, it carries a very poor prognosis with extrauterine survival being as little as a few days. Prostaglandin E1 may be given to initial management to keep the ductus open.

General differential considerations include:

Congenital heart disease

There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorised, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.

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Article Information

rID: 7805
System: Paediatrics
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Interrupted aortic arch
  • Interrupted aortic arch (IAA)
  • Aortic arch interruption
  • Interruption of aortic arch

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Cases and Figures

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    Figure 1: classification
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    On sagittal recon...
    Case 1: type A1
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    Case 2: type A1
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    Case 3: type B1
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    Case 3: 3D
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    Case 4: type B2 with truncus arteriosus
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    Case 5: type A1 with aortopulmonary window
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    Case 6: type B (antenatal ultrasound)
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