Coarctation of the Aorta

Key Features

Essentials of Diagnosis

• Usual presentation is systemic hypertension

• Echocardiography/Doppler is diagnostic; a peak gradient of > 20 mm Hg may be significant due to collaterals around the coarctation reducing gradient despite severe obstruction

• Associated bicuspid aortic valve in 50–80% of patients

• Delayed pulse in femoral artery compared to brachial artery

• Systolic pressure is higher in upper extremities than in lower extremities; diastolic pressures are similar

General Considerations

• Coarctation of the aorta consists of localized narrowing of the aortic arch just distal to the origin of the left subclavian artery

• If the stenosis is severe, collateral circulation develops around the coarctation site through the intercostal arteries and the branches of the subclavian arteries; a lower transcoarctation gradient can result by enabling blood flow to bypass the obstruction

• Coarctation is a cause of secondary hypertension and should be considered in young patients with elevated blood pressure

• The renin-angiotensin system is often abnormal and contributes to the residual hypertension occasionally seen even after coarctation repair

• A bicuspid valve is seen in approximately 50–80% of the cases, and there is an increased incidence of cerebral berry aneurysms

• Significant native or recurrent aortic coarctation has been defined as follows

  • Upper extremity/lower extremity resting peak-to-peak gradient > 20 mm Hg or mean Doppler systolic gradient > 20 mm Hg

  • Upper extremity/lower extremity gradient > 10 mm Hg or mean Doppler gradient > 10 mm Hg when there is either decreased LV systolic function or aortic regurgitation

  • Upper extremity/lower extremity gradient > 10 mm Hg or mean Doppler gradient > 10 mm Hg when there is evidence for collateral flow around the coarctation

Clinical Findings

• Usually no symptoms until hypertension produces left ventricular (LV) failure

• Cerebral hemorrhage occurs rarely

• Strong arterial pulsations in the neck and suprasternal notch

• Hypertension in the arms, but blood pressure is normal or low in the legs

• Delayed or weak femoral pulsations

• A continuous murmur heard superiorly and midline in the back or over the left anterior chest may be present when large collaterals occur and is a clue that the coarctation is severe

• Aortic regurgitation or stenosis murmur due to an associated bicuspid aortic valve may be present

• Coarctation is associated with Turner syndrome (a sex chromosomal abnormality [XO]); a webbed neck may be present in these patients

Diagnosis

Imaging

• Radiography

  • May show scalloping of the inferior portion of the ribs (rib notching) due to enlarged collateral intercostal arteries

  • Dilation of the left subclavian artery and poststenotic aortic dilation along with LV enlargement may be present

  • The coarctation region and the poststenotic dilation of the descending aorta may result in a "3" sign along the aortic shadow on the PA chest radiograph (the notch in the "3" representing the area ...