Congenital defects of the aortic arch are part of family of defects that range in severity from mild (coarctation of the aorta or COA) to serious (interrupted aortic arch). They are highly associated with other defects such as patent ductus arteriosis (PDA), patent foramen ovale (PFO), aortopulmonary shunt (AP window), ventricular septal defect (VSD) and other syndromes such as double outlet right ventricle (DORV) and truncus arteriosis. Interrupted aortic arch is also highly associated with the DiGeorge syndrome.
DiGeorge syndrome is a chromosomal disorder that affects many parts of body including the thyroid and parathyroid glands, neuromuscular problems, mild facial disorders, cleft palate, immune system deficiencies, kidney and gastrointestinal disorders and of course, congenital heart defects.
The first three large branches of the aorta are the brachiocephalic artery, which bifurcates into the right subclavian artery and the right common carotid artery, the left common carotid artery, and the left subclavian artery. It is just distal to the subclavian artery that the ductal part of the arch is found (also known as the ductus, isthmus, shelf) and is also the location of the fibrous ligament that attaches the pulmonary artery to the aorta. This is where a PDA will be located.
The genetic causes of these defects are a failure of the appropriate fetal cells that migrate to this area in vivo to generate a complete arch.
The gradient across the PDA may be mild or severe depending on the size of the lumen. If there is partial separation between the aortic arch and the thoracic aorta, this is an atretic aortic arch. If the separation is complete, this is an interrupted arch and blood supply to the distal arch is provided by the pulmonary trunk.
The most common area where separation occurs is at the isthmus. Less common is a separation between the left common carotid artery and the left subclavian artery. It is rare to see is separation more proximal in the aorta. The most common presentation is an absence of the isthmus, a persistently patent PDA and aVSD.
Associated lesions can be a right aortic arch, a double aortic arch, or a vascular ring.
Surgical repair generally consists of a balloon aortoplasty of the PDA with a stent placement, or an end-to-end anastomosis of the proximal and distal aorta with closure of the VSD.
For more information including pictures and surgical repairs, please refer to my book “Congenital Heart Defect, Simplified”
Ken Heiden RDCS