Interrupted aortic arch - type A1

Case contributed by Jacqueline Austine Uy
Diagnosis certain

Presentation

Congenital heart disease diagnosed when young, apparently without intervention. Dyspnea on exertion. Echo showed a VSD, severe mitral regurgitation and mild to moderate pulmonary regurgitation. She was referred to a tertiary medical center for further evaluation.

Patient Data

Age: 11 years
Gender: Female

There is discontinuity of the aortic arch distal to the take-off of the left subclavian artery.  The descending aorta emanates from the main pulmonary artery via a patent ductus arteriosus.  The innominate including the right subclavian and common carotid arteries, left common carotid and left subclavian arteries branch normally without evidence of stenosis or aberrant configuration.  The included intercostal and internal thoracic vessels are prominent with multiple collaterals.

The main, left and right pulmonary arteries are dilated without thrombus formation.  The pulmonary arteries are engorged relative to their accompanying bronchi, which likely relates to some degree of arterial hypertension.

The heart is enlarged, with multichambered dilatation.  A small membranous ventricular septal defect can be identified, although the interatrial septum is intact.

CT scout view demonstrates an enlarged heart with engorged pulmonary arterial vasculature.

On sagittal reconstruction, there is clearer delineation of the interrupted arch.

Axial representative image shows dilated main, left and right pulmonary arteries without definite filling defects.

Coronal view shows dilated main, left and right pulmonary arteries without definite filling defects.

Case Discussion

Known congenital heart disease, although no intervention was supposedly done when young. Dyspnea on exertion. 2D echocardiography showed a ventricular septal defect, severe mitral regurgitation and mild to moderate pulmonary regurgitation. She was referred to a tertiary medical center for further evaluation.

CT for the evaluation of interrupted aortic arch (IAA) is essential during presurgical planning, detection of associated cardiac anomalies, determination of the size of the patent ductus arteriosus, and presence of stenosis. CT also detects the presence of vascular collaterals such as in this patient, which allows for some individuals to survive to adulthood without surgical intervention. 90% of infants with interrupted aortic arches usually die within the first year of life from circulatory failure.

An interrupted aortic arch (IAA) type A (Celoria-Patton classification) is the second most common type (approximately 42% of all IAA cases), with type B the most common. This type A arch occurs when the interruption occurs beyond the left subclavian artery. The subclavian arteries of this patient are normal in configuration, without aberrant origin; hence, this may be further subdivided to subtype 1 (normal subclavian artery). The specific types and subtypes are further discussed in the main article regarding interrupted aortic arches.

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