Aortic Coarctation

• C. Russell Chen, M.D.
• Pranav M. Patel, M.D.

 Basic Information

Definition

Coarctation of the aorta is a narrowing of the aorta that occurs near the ligamentum arteriosum just distal to the origin of the left subclavian artery. It causes an outflow obstruction proximal to the site of the stenosis, which leads to left ventricular pressure overload, hypertrophy, and potentially heart failure. The stenosis can be discrete or long, and may have collateral vessels. It is commonly associated with other cardiac abnormalities such as a bicuspid aortic valve, patent ductus arteriosus, or ventricular septal defect.

Synonyms

1. Postductal coarctation of the aorta

2. Preductal coarctation of the aorta

3. Congenital hypoplasia of aortic arch

4. Coarctation of the aorta

ICD 10-CM CODES
Q25.1	Aortic coarctation

Epidemiology & Demographics

Aortic coarctation has a prevalence of approximately 4 per 10,000 live births and accounts for 6% to 8% of all congenital heart defects. It affects predominantly males, with a male to female ratio of 1.7:1.

Genetics

Although no specific genetic mutations have been identified, there have been case reports of coarctation occurring in families. Its association with a number of other conditions, such as Williams-Beuren and Sturge-Weber syndromes, also suggests a genetic predisposition. Most notably, up to 30% of patients with Turner syndrome also have coarctation of the aorta, and 5% to 15% of girls with coarctation have Turner syndrome.

Risk Factors

Aortic coarctation can be acquired through inflammatory conditions such as Takayasu arteritis or severe atherosclerosis.

Clinical Presentation & Physical Findings

1. •

   Clinical Presentation

   1. ○

      The clinical manifestations of coarctation of the aorta depend on the age of discovery, severity of the aortic narrowing, and adequacy of collateral circulation.

   2. ○

      Neonates with severe coarctation may present with heart failure and/or shock when the ductus arteriosus closes. Neonates without severe aortic coarctation or with a persistent patent ductus arteriosus may be asymptomatic.

   3. ○

      Beyond infancy, most patients are asymptomatic. Symptoms arise from severe hypertension, which may lead to headache, heart failure symptoms, or aortic dissection. Claudication of the lower extremities may also occur with physical exertion.

2. •

   Physical Exam Findings

   1. ○

      “Brachial-femoral” delay characterized by diminished or delayed femoral pulses compared to the brachial pulses.

   2. ○

      Upper extremity systolic hypertension.

   3. ○

      Low or unobtainable blood pressure in the lower extremities.

   4. ○

      Systolic ejection murmur at the left upper sternal border and left subscapular region.

   5. ○

      A continuous murmur heard best posteriorly over the thoracic spine may be heard if there are large collaterals.

   6. ○

      Systolic murmurs may be heard if there are coexisting cardiac defects (i.e., systolic ejection murmur with bicuspid aortic valve).

Etiology

1. •

   The exact pathogenesis is unknown. The two main theories for potential mechanisms are reduced antegrade intrauterine flow leading to underdevelopment of the fetal aortic arch and abnormal extension of tissue from the ductus arteriosus into the wall of the fetal thoracic aorta.

2. •

   In aortic coarctation, the arterial wall of the aorta has several pathologic abnormalities. There is cystic medial necrosis, increased stiffness and less distensibility, and increased collagen and less smooth muscle mass in the prestenotic segment.

Diagnosis

Differential Diagnosis

1. •

   Hypoplastic left heart syndrome

2. •

   Interrupted aortic arch

3. •

   Pseudocoarctation

4. •

   Left ventricular outflow tract obstruction, including subaortic and supravalvular aortic stenosis

5. •

   Critical aortic valve stenosis

6. •

   Obstructive peripheral arterial disease

7. •

   Aortic dissection

Work-Up

1. •

   Bilateral arm and leg blood pressures should be measured to search for a differential pressure.

2. •

   For patients with suspected aortic coarctation, the physical exam should include simultaneous palpation of the brachial and femoral pulses to assess for “brachial-femoral delay,” which is characteristic of significant aortic coarctation.

3. •

   An electrocardiogram may show left ventricular hypertrophy, ST-T wave abnormalities, and RV conduction delay.

4. •

   Transthoracic echocardiogram, including suprasternal notch acoustic windows, should be performed.

5. •

   Every patient with coarctation should have at least one cardiovascular MRI or CT scan for a complete evaluation of the thoracic aorta and intracranial vessels.

Laboratory Tests

1. •

   No specific laboratory tests are needed for coarctation of the aorta.

Imaging Studies

1. •

   Box E1 summarizes important findings in the imaging evaluation of coarctation of the aorta. Anomalies associated with aortic coarctation are described in Box E2.

   BOX E1Imaging Evaluation of Coarctation of the Aorta

   Patency of the Ductus Arteriosus

   Closed

   Patent

   Flow from aorta to pulmonary artery (typically postductal coarctation)

   Flow from pulmonary artery to aorta (preductal coarctation or pulmonary hypertension)

   Collateral Pathways

   Scarce (typical of patients under 2 years of age)

   Abundant

   Bridging the coarctated segment

   Internal mammary to intercostal to distal aorta

   Circumscapular pathways to distal aorta

   Other Arch Anomalies and Stenoses

   Arch interruption

   Double aortic arch with stenosis in either or both arches

   Coarctation proximal to left subclavian artery

   Takayasu aortitis, rubella, Williams syndrome, neurofibromatosis, mucopolysaccharidosis, and other causes of stenoses not in the aortic isthmus

   Subclavian Artery Anomalies

   Atresia or stenosis of the left subclavian artery

   Aberrant retroesophageal right subclavian artery

   Proximal to the coarctation

   Distal to the coarctation

   Origin of both subclavian arteries distal to the coarctation

   Associated Lesions

   Cardiac, such as ventricular septal defect or bicuspid aortic valve

   Aneurysms

   In aorta adjacent to coarctation

   In the ductus

   In the intercostal arteries

   In the circle of Willis

   (Boxt LM, Abbara S: Cardiac imaging: the requisites, ed 4, Philadelphia, 2016, Elsevier.)

   BOX E2Anomalies Associated with Aortic Coarctation

   Common

   Bicuspid aortic valve with stenosis and regurgitation

   Patent ductus arteriosus

   Ventricular septal defects

   Turner syndrome

   Rare

   Transposition of the great arteries

   Double-outlet right ventricle

   Shone’s syndrome (parachute mitral valve, supramitral ring, aortic valve stenosis, and aortic coarctation)

   (Boxt LM, Abbara S: Cardiac imaging: the requisites, ed 4, Philadelphia, 2016, Elsevier.)

2. •

   Chest X-ray (Fig. E1)

   1. ○

      Posterior rib notching of ribs 3-9 is due to bony erosion by large collateral arteries.

   2. ○

      The “3” sign is formed by an enlarged aortic knob and subclavian artery forming the upper portion of the 3, the indentation of the aortic wall at the site of the coarctation forming the waist, and the lower portion is formed by the post-stenotic dilatation of the proximal descending aorta.

      

3. •

   Echocardiography

4. •

   Generally, echocardiography is less useful for postoperative patients or for adult patients who may have less favorable acoustic windows compared with children.

   1. ○

      Aortic narrowing is visualized in the suprasternal notch view.

   2. ○

      Color flow imaging and pulsed Doppler localizes the area of coarctation.

   3. ○

      Continuous wave Doppler estimates the severity of coarctation.

   4. ○

      Associated cardiac defects, chamber sizes and left ventricular function can be evaluated.

5. •

   Magnetic Resonance Imaging & Computed Tomography

   1. ○

      Per 2008 ACC/AHA adult congenital heart disease guidelines, every adult patient with coarctation should have at least one cardiovascular MRI (Figs. E2 and E3) or CT (Fig. E4) or a complete evaluation of the thoracic aorta.

      

      

      

   2. ○

      The modalities have very high diagnostic accuracy (>95%) in detecting coarctation of the aorta and its associated abnormalities.

   3. ○

      Both provide a large field of view and allow simultaneous visualization of the ascending aorta, aortic arch, descending aorta, aortic valve, and collaterals.

   4. ○

      CT and MRI are indicated for serial follow up imaging after surgical repair to assess for aortic dilatation or aneurysm formation.

   5. ○

      MRI is preferred to CT to decrease the lifetime exposure to radiation.

6. •

   Cardiac Catheterization

   1. ○

      Cardiac catheterization (Fig. E5) may be used to assess the peak gradient across the coarctation, but is usually performed in conjunction with a therapeutic intervention.

Treatment

Acute General Rx

1. •

   Infants with critical coarctation are at risk for heart failure and death once the ductus arteriosus closes. Treatments include:

   1. ○

      Intravenous infusion of prostaglandin E1 to keep the ductus arteriosus patent.

   2. ○

      Dopamine and/or dobutamine to increase contractility for those with heart failure.

   3. ○

      Surgical repair once the patient is stabilized.

Chronic Rx

1. •

   Systemic hypertension should be treated with ACE inhibitors, angiotensin-receptor blockers, or beta-blockers.

2. •

   All patients with aortic coarctation should have long-term follow up with a congenital heart disease specialist.

3. •

   After repair, a CT or MRI of the repair site should be obtained at 1 year postoperatively and then every 5 years or less depending on anatomy to detect long-term complications.

Nonpharmacologic Therapy

Aortic coarctation can be repaired surgically or percutaneously by balloon angioplasty and/or stent placement. The choice of intervention is made on an individual basis based on aortic morphology and should be determined by a multidisciplinary team including cardiologists, interventionalists, and cardiac surgeons who are experienced in treating patients with congenital heart disease.

1. •

   Repair should be performed in infancy or early childhood to prevent the common complications of unrepaired coarctation, including systemic hypertension, accelerated coronary artery disease, stroke, heart failure, and aortic dissection.

2. •

   The indications for intervention according to the 2008 ACC/AHA guidelines for the management of adults with congenital heart disease are:

   1. ○

      Peak-to-peak coarctation gradient ≥20 mm Hg (Level of evidence C)

   2. ○

      Peak-to-peak coarctation gradient <20 mm Hg in the presence of anatomic imaging evidence of significant coarctation with radiologic evidence of significant collateral flow (Level of evidence C)

3. •

   Surgery

   1. ○

      Options include resection of coarctation and end-to-end anastomosis, a bypass graft across the area of coarctation, subclavian flap aortoplasty in long-segment coarctation, and prosthetic patch aortoplasty.

   2. ○

      Surgery compared with balloon angioplasty has been shown to be equally effective in reducing the peak systolic pressure gradient early after intervention.

   3. ○

      Surgery is indicated in the presence of a long re-coarctation segment, aortic aneurysm or pseudoaneurysm, or aortic arch hypoplasia.

4. •

   Balloon Angioplasty and/or Stent Placement

   1. ○

      Balloon angioplasty is the preferred intervention for patients with recurrent, discrete stenosis.

   2. ○

      Aortic stents placed in children will likely require a planned re-intervention to dilate the stent as the child grows.

   3. ○

      Potential complications of percutaneous intervention include immediate residual pressure gradients, re-coarctation, aneurysm formation, and femoral artery complications.

Referral

1. •

   All patients with coarctation of the aorta, with or without repair, should be referred to a congenital heart specialist.

2. •

   Intervention should involve a multidisciplinary team of cardiologists, interventionalists, and surgeons at an adult congenital heart disease center.

Pearls & Considerations

Comments

1. •

   Aortic coarctation is most commonly found distal to the origin of the left subclavian artery.

2. •

   The pathognomonic physical exam finding of aortic coarctation is the brachio-femoral delay.

3. •

   Systemic hypertension is the most common long-term complication of untreated aortic coarctation, but it is also associated with accelerated coronary artery disease, stroke, aortic dissection and heart failure.

4. •

   An adult congenital heart disease specialist should monitor all patients with aortic coarctation.

Suggested Readings

• M. Brown, H. Burkhart, H. Connolly, et al.: Coarctation of the aorta lifelong surveillance is mandatory following surgical repair. J Am Coll Cardiol. 62 (11):1020–1025 2013 23850909

• T.F. Feltes, E. Bacha, R.H. Beekman 3rd, et al.: Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association. Circulation. 123 (22):2607–2652 2013

• C.A. Warnes, R.G. Williams, T.M. Bashore, et al.: ACC/AHA 2008 guidelines for the management of adults with congenital heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Develop Guidelines on the Management of Adults With Congenital Heart Disease). J Am Coll Cardiol. 52:e143–e263 2008 19038677