Interrupted aortic arch
Updates to Article Attributes
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.
Epidemiology
It may account for ~1.5% of congenital cardiac anomalies.
Pathology
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
-
DiGeorge syndrome 1
- found commonly in those with a type B interruption
- almost always associated if there is a right
sided-sided descending aorta
- truncus arteriosus 8
- aortopulmonary septal defect (aortopulmonary window)
- transposition of the great arteries
- double outlet right ventricle
- functional single ventricle
Radiographic features
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
Treatment and prognosis
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.
Differential diagnosis
General differential considerations include:
- short segment severe aortic coarctation
-<strong>subtype 3:</strong> isolated subclavian artery that arises from the ductus arteriosus.</li>- +<strong>subtype 3:</strong> isolated subclavian artery that arises from the ductus arteriosus</li>
-<li>almost always associated if there is a right sided descending aorta</li>- +<li>almost always associated if there is a right-sided descending aorta</li>
Sections changed:
- Anatomy
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