Aortic Coarctation Workup

Updated: Feb 26, 2018
  • Author: Sandy N Shah, DO, MBA, FACC, FACP, FACOI; Chief Editor: Yasmine S Ali, MD, MSCI, FACC, FACP  more...
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Workup

Approach Considerations

The diagnosis of coarctation of the aorta generally can be made on clinical evaluation, particularly the physical examination. No specific laboratory tests are necessary.

Electrocardiogram (ECG) findings include the following:

  • Newborns and older children with milder forms of coarctation may have a normal ECG. If associated cardiac defects are present, then the ECG may be abnormal.
  • In older patients, long-standing coarctation of the aorta or a higher gradient across the coarctation stimulates left ventricular hypertrophy.

Cardiac catheterization can be used to determine the severity of coarctation, as follows:

  • If the peak gradient across the coarctation is below 20 mm Hg, the coarctation is mild.
  • A peak gradient above 20 mm Hg across the coarctation is suggestive of the need for intervention.
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Imaging Studies

Radiography

Radiographic findings include the following:

  • Radiographic findings vary with the clinical presentation of the patient. In coarctation diagnosed early in life, chest radiography shows cardiac enlargement and pulmonary venous congestion. Associated cardiac defects may mask these findings.

  • In older children, chest radiographic findings are usually normal. The study typically shows a prominent aortic knob, and the stenotic region may be observed as an indentation of the proximal thoracic descending aorta in the shape of a number 3.

  • Rib notching is observed as irregularities and scalloping on the undersurface of the posterior ribs. This finding is unusual in children younger than 5 years and is observed more frequently in patients with significant gradient across coarctation of long standing.

Esophagography

Barium esophagrams show the classic "E sign," representing compression from the dilated left subclavian artery and poststenotic dilatation of the descending aorta.

Echocardiography

Echocardiography can be used to dianose aortic coarctation. Note the following:

  • Diagnosis of coarctation of the aorta is made by two-dimensional echocardiography, pulsed-wave Doppler ultrasonography, and color flow mapping. Classic findings are narrowing of the isthmus and posterior indentation or shelf. Blood flow velocities proximal and distal to obstruction, measured by Doppler tracings, can be used to estimate pressure gradient across the coarctation by a modified Bernoulli equation. Color flow mapping shows changes in color at the site of obstruction due to increases in blood velocity and turbulence.

  • In older patients, coarctation may be difficult to diagnose by surface echocardiography. For these patients, magnetic resonance imaging (MRI), transesophageal echocardiography (TEE), or cardiac catheterization with angiography may be necessary to make the diagnosis.

Fetal echocardiography can be used to diagnose aortic coartation. Consider the following:

  • Detection of coarctation in utero is a difficult task for the echocardiographer.

  • Some features suggestive of the presence of coarctation include enlargement of the right ventricle compared to the left ventricle, reduction of the isthmus and transverse aortic diameters of less than 3% for gestational age, hypoplasia of left-sided structures, and decrease or reversal of flow in the foramen ovale.

MRI

MRI can be a useful study in suspcted aortic coartation. Note the following:

  • MRI is a sensitive test for location and extent of coarctation as well as involvement of adjacent vessels and presence of collaterals. However, it is expensive, time consuming, and not universally available.

  • MRI is seldom used as a primary diagnostic tool. It is a useful tool for detecting and monitoring aneurysms and restenosis.

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