A coarctation of the aorta is defined as a narrowing of the aorta, which is the main blood vessel that carries blood from the heart to the rest of the body. This type of heart defect is one of the more common ones, as it represents approximately 5% of all congenital heart malformations (with congenital heart defects occurring in approximately 0.8 to 1.2 out of 100 newborns, it still is relatively rare in the overall scheme of things).
Coarctation occurs most commonly in the short segment of the aorta just beyond where the arteries to the head and arms take off, right as it turns inferiorly towards the chest and abdomen. This area is called the aortic isthmus, or “juxtaductal” region, and it is where the ductus arteriosus attaches prenatally and shortly after birth. However, there are other less common locations of coarctation, including lower in the abdominal aortic region.
The exact cause of this congenital heart malformation is unknown. Recent research has identified multiple genetic factors associated with aortic arch narrowing (such as NOTCH-1). A prevailing theory is that tissue from the ductus arteriosus constricts around the aorta, thus causing the described narrowing.
In affected individuals, a coarctation of the aorta is present from birth. However, the age at which this defect is detected depends upon the severity of the narrowing. Also, while a coarctation may occur in isolation, it is often associated with other defects such as bicuspid aortic valve or ventricular septal defect. In more complex cases, there are also associations with conditions such as hypoplastic left heart syndrome (HLHS) or aortic arch hypoplasia. In addition, certain chromosomal abnormalities, such as Turner’s syndrome, are common in patients with coarctation of the aorta.
Coarctation is severe enough in 25-50% of cases to cause symptoms shortly after birth. Specifically, after the patent ductus arteriosus, or PDA, has closed, the left ventricle must pump against much higher resistance. This can lead to heart failure and shock quite quickly. In other, less severe cases, the only prevailing finding is high blood pressure. This accounts for the finding of coarctation in the aorta in teenagers or even adults.
In the critically ill neonate, management of the coarctation involves stabilization and ultimately surgery. An intravenous medicine called prostaglandin (PGE-1) is used to open/maintain the ductus arteriosus. Additional medications may be needed to improve heart function as well. On the other hand, a coarctation found in an otherwise symptomatic toddler/teenager/adult can be managed on a more non-emergent basis. .
Surgery can involve multiple different approaches, but overall success rates are very high. Following surgery, long term follow up is necessary to monitor for blood pressure issues, recurrent narrowing, or, on a rare occasion, aneurysm formation.
Listed below are some additional resources.
http://pediatricheartspecialists.com/heart-education
http://www.mayoclinic.org/diseases-conditions/coarctation-of-the-aorta/basics/definition/con-20031772
Amit Verma, M.D.
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