Interrupted aortic arch

Case contributed by Dr Anirudh Chawla

Presentation

Routine third trimester antenatal scan.

Patient Data

Age: 35 weeks gestational age
Gender: Male

Third trimester ultrasound scan

Modality: Ultrasound

Fetal ultrasound images at 35 weeks gestational age show dilated and hypertrophied right ventricle in 4 chamber view. 3 vessel trachea view shows dilated pulmonary trunk with hypoplastic ascending aorta. Ductal arch view shows normal ductal arch with normal flow pattern and velocities in ductus arteriousus. Aortic arch view shows hypoplastic aortic arch with aortic arch interruption between left common carotid and left subclavian artery.

Annotated images

Modality: Ultrasound

AO- ascending aorta, BC- brachiocephalic artery, DA- descending aorta, LA- left atrium, LC- left carotid artery, LS- left subclavian artery, LV- left ventricle, PA pulmonary artery, RA- right atrium, RV- right ventricle, SVC- superior vena cava.

Case Discussion

A 26 year female had presented for routine third trimester scan. The fetus corresponded to 35 weeks gestational age by fetal biometry. Dilated and hypertrophied right ventricle was noted in 4 chamber view and hence detailed fetal echo was performed. 3 vessel trachea view shows dilated pulmonary trunk with hypoplastic ascending aorta. Ductal arch view shows normal ductal arch with normal flow pattern and velocities in ductus arteriosus. Aortic arch view shows hypoplastic aortic arch with aortic arch interruption between left common carotid and left subclavian artery.

These imaging findings are highly suggestive of aortic arch interruption type B. Less likely differential diagnosis is severe coarctation of aorta. The left subclavian artery and descending aorta are receiving blood from the ductus arteriosus. There was no associated ventricular septal defect or aortopulmonary window. There was no systemic venous hypertension and no changes of hydrops fetalis. The fetus was delivered at term and expired on the first neonatal day.

Interrupted aortic arches are classified according to the site of interruption relative to the brachiocephalic vessels:

  • type A: interruption distal to the left subclavian artery (2nd most common)
  • type B: interruption distal to the left carotid artery (most common)
  • type C: interruption distal to the brachiocephalic artery
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Case Information

rID: 47780
Case created: 2nd Sep 2016
Last edited: 5th Oct 2016
Inclusion in quiz mode: Included

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