Aortic Coarctation

Practice Essentials

Aortic coarctation is a narrowing of the aorta most commonly found just distal to the origin of the left subclavian artery. The vascular malformation responsible for coarctation is a defect in the vessel media, giving rise to a prominent posterior infolding (the “posterior shelf”), which may extend around the entire circumference of the aorta.

Essential update: Risk factors associated with surgically repaired aortic coarctation

A review of 819 patients with isolated aortic coarctation who were treated surgically concluded that surgery should be performed early and patients followed for life because of the high risk of cardiovascular consequences.[1, 2] In this study, most patients received a simple or extended end-to-end anastomosis (n = 632); the remainder received patch angioplasty (n = 72), interposition grafts (n = 49), bypass grafts (n = 30), or subclavian flaps or other procedures (n = 35). Mean age at repair was 17.2 years; mean follow-up was 17.4 years.

Actuarial survival was 93.3% at 10 years, 86.4% at 20 years, and 73.5% at 30 years. Mean age at death was 34 years.[2] Older age at repair (>20 years) and preoperative hypertension were significantly associated with decreased survival. In all, 124 patients required a reoperation at some point, primarily for aortic valve replacement (n = 52) or another coarctation intervention (n = 53). Younger age at the time of repair and an end-to-end anastomosis were each independently associated with lower reintervention rates on the descending aorta (P

Compared with age- and gender-matched controls, patients who underwent surgery for aortic coarctation had significantly reduced long-term survival (P [2] Patients treated before the age of 5 years were at higher risk for reoperation, whereas those treated when they were older than 9 years had more residual hypertension.

Signs and symptoms

Symptoms of aortic coarctation may include the following:

Early life – Congestive heart failure, severe acidosis, or poor perfusion to the lower body.Beyond infancy – Usually none; however, hypertension, headache, nosebleed, leg cramps, muscle weakness, cold feet, or neurologic changes may be seen

The diagnosis of coarctation generally can be made on the basis of physical examination. Blood pressure differential and pulse delay are pathognomonic. The following physical findings may be noted:

Frequently normal physical appearance (except when coarctation compromises the origin of the left subclavian artery or in cases of XO Turner syndrome) Abnormal differences in upper- and lower-extremity arterial pulses and blood pressures; diminished and delayed pulses distal to obstruction Characteristic murmurs and sounds on auscultation (eg, continuous or late systolic murmur posteriorly over the thoracic spine, bilateral collateral arterial murmurs, aortic ejection sound, short midsystolic murmur, or early diastolic murmur of aortic regurgitation) Associated cardiac defects (eg, left-side obstructive or hypoplastic defects and ventricular septal defects, bicuspid aortic valve, aortic arch hypoplasia, and, rarely, various right-side cardiac obstructive lesions) Extracardiac vascular anomalies (eg, aberrant subclavian artery, berry aneurysms of the circle of Willis, development of large upper-to-lower collateral arteries, or hemangiomas) Extracardiac nonvascular anomalies (eg, head and neck, musculoskeletal, gastrointestinal, genitourinary, or respiratory)

See Presentation for more detail.

Diagnosis

No specific laboratory tests are necessary for coarctation of the aorta. Imaging studies that may be helpful include the following:

Chest radiography – Findings vary with the clinical presentation of the patientBarium esophagography – Classic “E sign,” representing compression from the dilated left subclavian artery and poststenotic dilatation of the descending aorta Echocardiography (2-dimensional echocardiography, pulsed-wave Doppler, and color flow mapping) – In older patients, surface echocardiography may not suffice, and magnetic resonance imaging (MRI), transesophageal echocardiography (TEE), or cardiac catheterization with angiogram may be necessary Fetal echocardiographyMRI – This test is sensitive but expensive, time-consuming, and not universally available; it is seldom used as a primary diagnostic tool

Other studies that may be useful are as follows:

Cardiac catheterizationElectrocardiography

See Workup for more detail.

Management

Medical treatment of neonates with severe aortic coarctation may include the following:

IntubationInfusion of prostaglandin E1 (PGE1) to open the ductus arteriosusCorrection of acidosisInotropic support to improve symptoms of congestive heart failure (CHF)

Medical treatment of less severe aortic coarctation beyond the neonatal period may include the following:

Administration of digoxin and diuretics for chronically increased afterload and signs of CHFPostponement of intervention (eg, surgery or balloon dilatation) until the patient is hemodynamically stable

At present, the following 3 specific indications exist for intervention:

Significant coarctation or recoarctation of the aorta with long-standing hypertension with or without symptomsHemodynamically significant aortic stenosisFemale patient contemplating pregnancy

The following surgical procedures have been performed to treat aortic coarctation:

Resection of the coarctation site and end-to-end anastomosis to repair coarctation (still the preferred surgical method)Patch aortoplastyLeft subclavian flap angioplastyBypass graft repair bridging the ascending and descending aorta

Catheter-based intervention is now the preferred therapy for recurrent coarctation when the anatomy permits and necessary skills are available. Its use in native or unoperated coarctation is less well established.

See Treatment and Medication for more detail.

NextBackground

Coarctation of the aorta is a narrowing of the aorta most commonly found just distal to the origin of the left subclavian artery. Most patients with coarctation have juxtaductal coarctation. Older terms, such as preductal (infantile-type) or postductal (adult-type), are often misleading.

ACC/AHA 2008 guidelines of coarctation of aorta in adults (adapted)

Recommendations for clinical evaluation and follow-up[3]

Class I recommendations are as follows:

Every patient with systemic arterial hypertension should have brachial and femoral pulses palpated simultaneously to assess timing and amplitude evaluation to search for the brachial-femoral delay of significant aortic coarctation. Supine bilateral arm (brachial artery) blood pressures and prone right or left supine (popliteal artery) blood pressures should be measured to search for differential pressure - level of evidence, C Initial imaging and hemodynamic evaluation by transthoracic echocardiogram, including suprasternal notch acoustic windows, is useful in suspected aortic coarctation - level of evidence, B Every patient with coarctation (repaired or not) should have at least one cardiovascular MRI or CT scan for complete evaluation of the thoracic aorta and intracranial vessels - level of evidence, B

Recommendations for interventional and surgical treatment

Class I recommendations are as follows:

Intervention for coarctation is recommended in the following circumstances: (1) Peak-to-peak coarctation gradient greater than equal to 20 mm Hg (level of evidence, C) and (2) Peak-to-peak coarctation gradient less than 20 mm Hg in the presence of anatomic imaging evidence of significant coarctation with radiological evidence of significant collateral flow (level of evidence, C) Choice of percutaneous catheter intervention versus surgical repair of native discrete coarctation should be determined by consultation with a team of adult congenital heart disease cardiologists, interventionalists, and surgeons at the adult congenital heart disease center - level of evidence, C Percutaneous catheter intervention is indicated for recurrent, discrete coarctation and a peak-to-peak gradient of 20 mm Hg - level of evidence, B Surgeons with training and expertise in congenital heart disease should perform operations for previously repaired coarctation and the following indications: (1) Long recoarctation segment (level of evidence, B) and (2) concomitant hypoplasia of the aortic arch (level of evidence, B)

Class IIb recommendation is as follows:

Stent placement for long-segment coarctation may be considered, but the usefulness is not well established and the long-term efficacy and safety are unknown - level of evidence, C

Recommendations for key issues for evaluation and follow-up

Class I recommendations are as follows:

Lifelong cardiology follow-up is recommended for all patients with aortic coarctation (repaired or not), including an evaluation by or consultation with a cardiologist with expertise in ACHD - level of evidence, C) Patients who have had surgical repair of coarctation at the aorta or percutaneous intervention for coarctation of the aorta should have at least yearly follow-up - level of evidence, C Even if the coarctation repair appears to be satisfactory, late postoperative thoracic aortic imaging should be performed to assess for aortic dilatation or aneurysm formation - level of evidence, B Patients should be observed closely for the appearance or reappearance of resting or exercise-induced systemic arterial hypertension, which should be treated aggressively after recoarctation is excluded - level of evidence, B Evaluation of the coarctation repair site by MRI/CT scan should be performed at intervals of 5 years or less, depending on the specific anatomic findings before and after repair - level of evidence, C

Class IIb recommendation is as follows:

Routine exercise testing may be performed at intervals determined by consultation with the regional ACHD center - level of evidence, C

For the full guidelines, see ACC/AHA 2008 Guidelines for the Management of Adults With Congenital Heart Disease.

PreviousNextPathophysiology

The vascular malformation responsible for coarctation is a defect in the vessel media, giving rise to a prominent posterior infolding (the "posterior shelf"), which may extend around the entire circumference of the aorta. The gross pathology of coarctation varies considerably. The lesion is often discrete but may be long, segmental, or tortuous in nature.

Histology

The coarctated aortic segment reveals an intimal and medial lesion consisting of thickened ridges that protrude posteriorly and laterally into the aortic lumen. The ductus (ie, patent embryonic remnant) or ligamentum arteriosus (closed and fibrosed) inserts at the same level anteromedially. Intimal proliferation and disruption of elastic tissue may occur distal to the coarctation. At this site, infective endarteritis, intimal dissections, or aneurysms may occur. Cystic medial necrosis occurs commonly in the aorta adjacent to the coarctation site and acts as a substrate for late aneurysm formation or aortic dissection in some patients.

Embryology

Coarctation is due to an abnormality in development of the embryologic left fourth and sixth aortic arches that can be explained by 2 theories, the ductus tissue theory and the hemodynamic theory.

In the ductus tissue theory, coarctation develops as the result of migration of ductus smooth muscle cells into the periductal aorta, with subsequent constriction and narrowing of the aortic lumen. Commonly, coarctation becomes clinically evident with closure of the ductus arteriosus. This theory does not explain all cases of coarctation. Clinically, coarctation may occur in the presence of a widely patent ductus arteriosus, and it may occur quite distant from the insertion of the ductus arteriosus, such as in the transverse arch or abdominal aorta.

In the hemodynamic theory, coarctation results from reduced volume of blood flow through the fetal aortic arch and isthmus. In a normal fetus, the aortic isthmus receives a relatively low volume of blood flow. Most of the flow to the descending aorta is derived from the right ventricle through the ductus arteriosus. The left ventricle supplies blood to the ascending aorta and brachiocephalic arteries, and a small portion goes to the aortic isthmus. The aortic isthmus diameter is 70-80% of the diameter of the neonatal ascending aorta.

Based on this theory, lesions that diminish the volume of left ventricular outflow in the fetus also decrease flow across the aortic isthmus and promote development of coarctation. This helps to explain the common lesions associated with coarctation, such as ventricular septal defect, bicuspid aortic valve, left ventricular outflow obstruction, and tubular hypoplasia of the transverse aortic arch. This theory does not explain isolated coarctation without associated intracardiac lesions.

PreviousNextFrequencyUnited States

This condition represents 5-10% of all congenital cardiac lesions. It represents 7% of critically ill infants with heart disease.

PreviousNextMortality/MorbidityPatients who are not treated for coarctation of the aorta may reach the age of 35 years; fewer than 20% survive to age 50 years. If coarctation is repaired before the age of 14 years, the 20-year survival rate is 91%. If coarctation is repaired after the age of 14 years, the 20-year survival rate is 79%. After repair of the aortic coarctation, 97-98% of patients are New York Heart Association (NYHA) class I. Impaired diastolic left ventricular function and persistent hypertrophy due to increased pressure gradient at the coarctation site during exercise may result in myocardial hypertrophy despite successful hemodynamic results. Overall, left ventricular systolic function is normal or hyperdynamic in these patients. Pregnancy: Most women reach childbearing age. If maternal coarctation is not repaired, the risk to fetus and mother is increased. The maternal mortality rate is approximately 3-8%. Even women who have had their coarctation repaired have an increased risk of aortic dissection and rupture of a cerebral aneurysm in the third trimester and peripartum period due to hemodynamic and hormonal changes. All pregnant women with a history of coarctation, either native or repaired, should be considered high risk. Significant stenosis—native, residual, or recurrent—is a contraindication to pregnancy. Race

Coarctation is 7 times more common in whites than Asian persons. It has a lower incidence among Native Americans than other population groups in Minnesota.

Sex

Male-to-female predominance is 1.3-2:1 in most series.

Age

Age at detection of coarctation of the aorta is dependent on severity of obstruction and coexistence of other lesions.

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