Right-sided aortic arch is a rare anatomical variant in which the

aortic arch The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins ...

is on the right side rather than on the left. During normal

embryonic development In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm, sperm cell (spermat ...

, the aortic arch is formed by the left fourth

and the left dorsal aorta. In people with a right-sided aortic arch, instead the right dorsal aorta persists and the distal left aorta disappears.

Symptoms and signs

A right-sided aortic arch does not cause symptoms on itself, and the overwhelming majority of people with the right-sided arch have no other symptoms. However, when it is accompanied by other vascular abnormalities, it may form a

vascular ring A vascular ring is a congenital defect in which there is an abnormal formation of the aorta and/or its surrounding blood vessels. The trachea and esophagus are completely encircled and sometimes compressed by a "ring" formed by these vessels, whic ...

, causing symptoms due to compression of the

trachea The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...

and/or

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

Pathophysiology

The causes of right-sided aortic arch are still unknown, 22q11 deletions have been found in some people with this condition. It has also been found in association with other genetic syndromes such as Trisomy 21 (Down syndrome).

Diagnosis

Rechts descendierende Aorta - Roe seitlich

During pregnancy, prenatal ultrasound may reveal the abnormal course of the arch and this is the most common reason for identification of a right sided aortic arch nowadays. Sometimes, when a right sided aortic arch is seen before birth, it can actually be a double aortic arch, sometimes a fetal MRI scan may be helpful if the ultrasound is not clear. After birth, a right-sided aortic arch is visualized on chest radiography, by the aortic knob (the prominent shadow of the aortic arch) that is located right from the

sternum The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...

instead of left. Complex lesions are often assessed by

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

or CT.

Classification

Several types of right-sided aortic arch exist, the most common ones being right-sided aortic arch with aberrant left subclavian artery and the mirror-image type. The variant with aberrant left subclavian artery is associated with

congenital heart disease A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital he ...

in only a small minority of affected people. The mirror-image type of right aortic arch is very strongly associated with congenital heart disease, in most cases

tetralogy of Fallot Tetralogy of Fallot (TOF), formerly known as Steno-Fallot tetralogy, is a congenital heart defect characterized by four specific cardiac defects. Classically, the four defects are: * Pulmonary stenosis, which is narrowing of the exit from the r ...

Management

If a right aortic arch is associated with a left sided arterial ductal ligament (a remnant from the foetal circulation which forms a ligament after birth) then a vascular ring is formed around the trachea. Studies show that around 1:4 children show symptoms of a vascular ring. This requires further investigation by specialists. Many children are well. There is evidence to show that symptoms of a vascular ring do not correlate with the appearance of the trachea in these patients so further assessment may be required. This could be in the form of a specialist CT scan which is timed with inspiration and expiration or a free breathing bronchoscopy. If required, repairing a vascular ring formed by a right sided aortic arch usually involves dividing the left sided arterial ductal ligament (this is not a structure that is necessary for the heart circulation as it is not a vessel after birth). This is usually performed by cardiothoracic surgeons from the side of the chest (thoracotomy incision) and does not require the heart to be stopped like many heart surgeries. Some people may have an aberrant left subclavian artery (the artery to the left arm) and this may also require re-implantation as it adds to the complexity of the vascular ring.

Epidemiology

Right-sided aortic arch is rare, with a

prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...

among adults of about 0.01%.

References

External links

Radiopaedia: Aortic arch variants

eMedicine: Right Aortic Arch in Vascular Ring Defects
{{Congenital vascular defects Congenital vascular defects