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.

Epidemiology

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

Pathology

Faulty embryological development of the aortic arch (thought to occur during the 5 to 7 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 :

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

Radiographic features

Plain radiograph

Plain film features are often non-specific:

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 .

CT

Allows visualization of the interrupted aortic arch and associated anomalies.

MRI
  • non-visualization of the portion of interruption
  • great vessels may show a "V" configuration on coronal imaging

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. Surgical correction (either single- or multistage) is the definitive treatment.

Differential diagnosis

General differential considerations include: