Coarctation of the aorta is a narrowing of the aorta. In 98% of patients, the narrowing is classically divided into infantile and adult forms. The infantile form is associated with a patent ductus arteriosus (PDA) and the coarctation occurs distal to the aortic arch, but proximal to the PDA. In the adult form, the coarctation occurs distal to the aortic arch and just across from or distal to the closed ductus arteriosus (called the ligamentum arteriosum).
Coarctation of the aorta is twice as common in males as in females. However, females with Turner Syndrome (45, XO) are frequently affected with coarctation of the aorta. Another important association is the increased risk of intracranial aneurysms (berry aneurysms).
Older infants and children are often asymptomatic and present with hypertension. They may also have murmurs caused by collateral blood flow or associated heart defects as well as chest pain or claudication. Adults typically present with hypertension, claudication and headaches.
The classic physical exam finding is higher systolic blood pressure in the upper extremities when compared to the lower extremities.
In neonates with severe coarctation, heart failure may develop after the PDA closes because there is not enough time for the development of collateral blood flow or myocardial hypertrophy. Although heart failure rarely occurs beyond the neonatal period, adults may develop heart failure if severe hypertension is present.
Using an ultrasound, sound waves are used to visualize the structures of the heart and aorta. These can be performed in a both transthoracic and transesophageal fashion with the transesophageal echocardiogram (TEE) being the best choice to visualize the heart structures posteriorly.
Other tests used to diagnose the defect and measure the function of the heart include cardiac catheterization, MRI and CT.
The figure 3 sign on chest x-ray represents the contour abnormality of the aorta. It is formed by dilation of the aortic arch and left subclavian artery, indentation at the coarctation site and dilation of the descending aorta. It is important to note that dilation of the ascending aorta is common and may be visualized but the characteristic "3" sign is mostly due to dilation of the descending portion.
In order to bypass the coarctation and supply the descending aorta, the intercostal collateral vessels begin to dilate. The dilated vessels erode the inferior parts of the ribs, resulting in notching. Since collateral circulation takes time to develop, rib notching is unusual in patients less than 5 years old.
For patients with recurrent coarctation (restenosis after a successful operation), balloon angioplasty with or without stent placement can be performed.
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