Coarctation of the Aorta

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

• 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

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 of coarctation)

• Echocardiography/Doppler

  • Usually diagnostic

  • May provide additional evidence for a bicuspid aortic valve.

• Both MRI and CT can provide excellent images of the coarctation anatomy, and one or the other should always be done to define the coarctation anatomic structure

• MRI and echocardiography/Doppler can also provide estimates of the gradient across the lesion

Diagnostic Procedures

• The ECG usually shows LV hypertrophy (LVH)

• Cardiac catheterization provides definitive gradient information and is necessary if percutaneous stenting is to be considered

• Patients with a demonstrated peak gradient of > 20 mm Hg should be considered for intervention, especially if there is evidence of collateral blood vessels

• The percutaneous interventional procedure of choice is endovascular stenting; when anatomically feasible, self-expanding and balloon-expandable covered stents have been shown to be advantageous over bare metal stents

• Most coarctation repair in adults is percutaneous

• Otherwise, surgical resection (usually with end-to-end anastomosis) should be performed

Follow-Up

• Recurrence of the coarctation stenosis following intervention requires long-term follow-up

Prognosis

• Many untreated patients with severe coarctation die of hypertension, rupture of the aorta, infective endarteritis, or cerebral hemorrhage before the age of 50

• Aortic dissection also occurs with increased frequency

• Resection of the coarctation site has a surgical mortality rate of 1–4% and includes risk of spinal cord injury

• Coarctation of any significance may be poorly tolerated in pregnancy because of the inability to support the placental flow

• About 25–50% of surgically corrected patients continue to be hypertensive years after surgery because of permanent changes in the renin-angiotensin system, endothelial dysfunction, aortic stiffness, altered arch morphology, and increased ventricular stiffness

When to Refer

• All patients with aortic coarctation and any detectable gradient should be referred to a cardiologist with expertise in adult congenital heart disease