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.
Symptoms of aortic coarctation may include the following:
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:
See Presentation for more detail.
No specific laboratory tests are necessary for coarctation of the aorta. Imaging studies that may be helpful include the following:
Other studies that may be useful are as follows:
See Workup for more detail.
Medical treatment of neonates with severe aortic coarctation may include the following:
Medical treatment of less severe aortic coarctation beyond the neonatal period may include the following:
At present, the following 3 specific indications exist for intervention:
The following surgical procedures have been performed to treat aortic coarctation:
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.
Coarctation of the aorta (CoA), a narrowing of the aorta most commonly found just distal to the origin of the left subclavian artery, is a common condition found in children. Most patients with coarctation have juxtaductal coarctation. Older terms, such as preductal (infantile-type) or postductal (adult-type), are often misleading.
This condition occurs in 40 to 50 of every 100,000 live births and has a male-to-female predominance of 2:1.[1] Aortic coarctation is commonly treated after birth or during childhood.
Coarctation of the aorta is rarely seen in adults[1, 2, 3] However, when affected adults present, they may have a history of a previous coarctation procedure, rupture of an old repair, heart failure, aortic aneurysm, aortic dissection, undersized grafts of previous repairs, intracranial hemorrhage, hypertension with exercise, and infections.[1]
The prognosis for untreated aortic coarctation is poor. About 80% of untreated patients die of aortic dissection or rupture, heart failure, or intracranial hemorrhage.[1] The traditional treatment for coarctation of the aorta is open surgery. A less-invasive treatment option is endovascular balloon dilatation and stent placement.[1]
See the Guidelines section for a summary of guidelines for the management of aortic coarctation in adults.
The vascular malformation responsible for aortic 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.
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.
Coarctation is due to an abnormality in development of the embryologic left fourth and sixth aortic arches that can be explained by two 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 the 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. However, this theory does not explain isolated coarctation without associated intracardiac lesions.
The exact etiology of coarctation of the aorta is not known. Note the following:
Coarctation of aorta represents 5%-8% of all congenital heart diseases,[6, 7] with the isolated form comprising 4%-6% of all congenital heart diseases.[8] The prevalence of isolated forms is about 3-4 per 10,000 live births,[6, 8] and males are affected more frequently than females.[9]
Aortic coarctation is seven times more common in white persons than Asian persons. It has a lower incidence among Native Americans than other population groups in Minnesota.
The male-to-female predominance is 1.3-2:1 in most series.
The age at detection of coarctation of the aorta is dependent on the severity of the obstruction and the coexistence of other lesions.
Patients who are not treated for coarctation of the aorta may reach the age of 35 years[10] ; about 25% survive to age 46 years,[10] and 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%. The 30-year survival rate is almost doubled with surgical repair, with 72%-98% of these patients reaching adulthood.[11]
After repair of coarctation of the aorta, 97%-98% of patients are 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
Most women reach childbearing age. If maternal coarctation is not repaired, risks to fetus and mother are increased. The maternal mortality rate is approximately 3%-8%. Note the following:
Late complications of aortic coarctation include recurrent coarctation, malignant hypertension, left ventricular dysfunction, aortic valve dysfunction, and aneurysm formation with risk of rupture.[11]
Postoperative complications include the following:
Most adults with aortic coarctation have previously undergone repair; however, continued education regarding exercise, endocarditis and endarteritis prevention, and pregnancy issues is necessary.
For the rare adult with uncorrected coarctation, extensive patient education is necessary on issues ranging from pathology and repair to lifestyle modification and follow-up care.
The medical practitioner must understand that coarctation is a complex lifelong condition that may be repaired but is never truly corrected.
Depending on severity of the obstruction and associated cardiac lesions, patients with aortic coarctation may present with congestive heart failure, severe acidosis, or poor perfusion to the lower body.[10]
Newborns typically present with severe narrowing of the upper thoracic aorta below the isthmus and adjacent to the arterial duct.[7]
Patients are usually asymptomatic. They may present with hypertension, headache, nosebleed, leg cramps, muscle weakness, cold feet, or neurologic changes.
The diagnosis of coarctation of the aorta generally can be made on physical examination. A blood pressure differential and brachial-femoral pulse delay are pathognomonic.
Patients may appear healthy. If coarctation compromises the origin of the left subclavian artery, the left arm is smaller than normal. Otherwise, general development is normal.
In XO Turner syndrome, a condition frequently associated with coarctation, a phenotypic female has the following features: short stature, webbed neck, absent or scanty axillary and pubic hair, broad chest and widely spaced hypoplastic or inverted nipples, low posterior hairline, small chin, prominent ears, cubitus valgus, short fourth metacarpals and metatarsals, distal palmar triaxial radii, narrow hyperconvex nails, and extensive pigmented cutaneous nevi.
Abnormal differences in the upper and lower extremity arterial pulses and blood pressures are clinical hallmarks of coarctation of the aorta. Pulses distal to the obstruction are diminished and delayed. This may be appreciated best by simultaneous arm and leg pulse palpation.
A continuous "machinery" murmur throughout both systole and diastole or a late systolic murmur is best heard posteriorly over the thoracic spine. Collateral arterial murmurs are crescendo-decrescendo in shape and delayed in onset and termination because of their origins in vessels some distance from the heart. The collateral murmurs are present bilaterally.
If the patient has an associated bicuspid aortic valve, an aortic ejection sound, a short midsystolic murmur, and/or early diastolic murmur of aortic regurgitation may be audible.
Associated cardiac defects are observed in approximately 50% of patients with aortic coarctation.
The most commonly reported defects are left-sided obstructive or hypoplastic defects and ventricular septal defects. Bicuspid aortic valve is observed in 85% of patients. Also, aortic arch hypoplasia is commonly found in coarctation associated with intracardiac defects.[12]
Right-sided cardiac obstructive lesions, such as pulmonary stenosis, pulmonary atresia, or tetralogy of Fallot, are observed rarely.
Extracardiac vascular anomalies commonly occur in patients with aortic coarctation. A right subclavian artery that arises aberrantly from the descending aorta distal to the coarctation occurs in 5% of patients. Rarely, both subclavian arteries originate distal to the coarctation.
Berry aneurysms of the circle of Willis occur in 3%-5% of patients and may result in subarachnoid bleeding.
After years of coarctation, large collateral arteries develop from the upper to lower body (ie, internal mammary arteries connecting to external iliac arteries, and spinal and intercostal arteries connecting to the descending aorta).
Hemangiomas also have been reported with coarctation.
Extracardiac nonvascular anomalies occur in 25% of patients with coarctation of the aorta. Coarctation of the aorta occurs in 35% of patients with Turner syndrome.
Abnormalities of the musculoskeletal, genitourinary, gastrointestinal, or respiratory system may be observed in as many as 25% of children with coarctation. In addition, an increasing number of children have head and neck abnormalities observed by ultrasonography.
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:
Cardiac catheterization can be used to determine the severity of coarctation, as follows:
Radiographic findings include the following:
Barium esophagrams show the classic "E sign," representing compression from the dilated left subclavian artery and poststenotic dilatation of the descending aorta.
Echocardiography can be used to dianose aortic coarctation. Note the following:
Fetal echocardiography can be used to diagnose aortic coartation. Consider the following:
MRI can be a useful study in suspcted aortic coartation. Note the following:
Neonates with severe coarctation of the aorta should first have their condition stabilized:
Patients presenting with less severe coarctation of the aorta beyond the neonatal period usually have chronically increased afterload and show signs of congestive heart failure. These patients should be treated with digoxin and diuretics.
Attempts should be made to postpone intervention, such as surgery or balloon dilatation, until the patient is hemodynamically stable.
Surgical repair has approximately doubled the 30-year survival of patients with aortic coarctation, with 72%-98% of these individuals reaching adulthood.[11]
No single technique is superior to others in minimizing the rate of restenosis in patients with aortic coarctation. In addition, there is no consensus regarding the optimal surgical technique in adolescents and adults with aortic coarctation.[3] The preferred method depends on anatomy of the lesion and institutional experience.
Three specific indications currently exist for intervention in patients with coarctation of the aorta, as follows:
Surgical procedures used in the treatment of coarctation of the aorta include the following[1] :
In 1944, Blalock and Park performed the first experimental surgical repair of coarctation of the aorta in animals, which involved use of the left common carotid or subclavian artery to bypass the coarctation with end-to-end anastomosis.[13]
Resection of the coarctation site and end-to-end anastomosis to repair coarctation was performed first on humans in 1945 by Crafoord, Nylin, Gross, and Hufagel.[14] This is the preferred surgical method even in the present time. In this technique, the aorta is cross-clamped above and below the obstruction, and the discrete narrowing is resected. The advantages of this procedure are that the obstructed site is completely resected, and it also avoids the use of prosthetic material and maintains a functioning left subclavian artery. The disadvantages of this procedure involve the sacrifice of spinal and intercostal vessels, resulting in paralysis. Also, a high rate of restenosis exists with use of continuous running suture or circumferential fibrosis. This problem is overcome by the use of interrupted and absorbable sutures, which allows for improved growth of the anastomotic site.
Patch aortoplasty was first performed by Vossschulte in 1961 to repair coarctation of the aorta.[15] This technique involves cutting across the obstruction and augmenting the area with a patch of prosthetic material. The advantagesof this procedure include the ability to repair a long segment of coarctation; sparing of the left subclavian, intercostal, and spinal arteries; and preserving native aortic tissue to allow for growth. The disadvantage of this procedure is that it uses prosthetic material, which may gradually result in aneurysm formation.
Left subclavian flap angioplasty, introduced in 1966 by Waldhausen and Nahrwold, involves ligating the left subclavian artery and dividing it distally.[16] A longitudinal incision is made from the descending aorta to the coarctation superiorly into the origin of the left subclavian artery. The subclavian artery is turned down and used to enlarge the narrowing. To prevent subclavian steal phenomena, the vertebral artery is ligated. The advantages to this procedure include preservation of native vascular tissue and avoidance of circumferential sutures, which allows for better growth of the involved area. The disadvantage to this procedure is the sacrifice of a major artery to the left arm, resulting in poor growth of that extremity.
Bypass graft repair bridges the ascending and descending aorta. The major disadvantage of this procedure is that the prosthetic material does not grow as the child grows, and it becomes calcified and narrow with time.
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. Treatment may be with balloon angioplasty alone or with a stent.[17] Outcomes are good in skilled hands, but residual or recurrent coarctation with resultant hypertension and repair site aneurysms can occur. Catheter-based treatment can cause death from aortic rupture and dissection, but mortality compares favorably with surgery if coarctation is recurrent, and perhaps for initial treatment.
In the Coarctation of the Aorta Stent Trial (COAST), investigators assessing the safety and efficacy of the Cheatham Platinum stent when used in 104 patients with native or recurrent coarctation, with follow-up to 2 years, found that the stent is safe and that its use is associated with persistent relief of aortic obstruction.[18] Reintervention was common; it was related to early and late aortic wall injury and to the need for re-expansion of small-diameter stents.
In another study, investigators analyzed their 21-year experience in the percutaneous treatment of complex coarctation of aorta at Reina Sofia University Hospital and found that initial results were maintained at later follow-up, and that the actuarial survival free probability of all complex patients at 15 years was 92%.[19] The study provided evidence that stent repair of complex coarctation of aorta is feasible and safe.
In an institutional study that assessed their 15-year experience of native aortic stenting in 24 patients aged 46 years and older, investigators found implantation of bare-metal and covered stents using femoral access were safe and effective.[20]
A more recent, retrospective study of outcomes of thoracic endovascular aortic repair (TEVAR) in 21 adults with primary coarctation of the aorta or late sequelae of previous open repair indicates this procedure is safe and effective in this population.[2] In addition, the stent graft successfully dilated the annular constriction of the coarctation site. The 1-year freedom from intervention was 78%, and the 1- and 3-year survival was 95%.[2]
The immediate improvement in hypertension and morbidity appeared to be similar across all groups when endovascular repair was compared to surgical repair.[21] However, surgical therapy was associated with a low risk of restenosis and recurrence, whereas endovascular therapy had much higher incidence of restenosis and need for repeat interventions.
Endovascular therapy is highly promising in elderly and frail patients with multiple comorbidities who pose a high surgical risk. Overall, long-term outcome of endovascular approaches need to be evaluated.
The 2015 American College of Cardiology/American Heart Association (ACC/AHA) scientific statement indicates that, before a patient's participation into a sports, a detailed evaluation should be perfomed, including physical examination, electrocardiography, chest x-ray, exercise testing, and cardiac/aortic imaging (transthoracic echocardiogram, magnetic resonance imaging [MRI], and/or computed tomography angiography [CTA]).[22] The time interval to repeat these tests is not clear, and it should be individualized to the specific patient.
Patients with an unrepaired coarctation can participate in all competitive sports if they meet all of the following criteria (class I)[22] :
Patients with arm-leg systolic blood pressure gradient above 20 mm Hg or exercise induced hypertension (peak systolic pressure >95th percentile of predicted with exercise) or with significant ascending aortic dilatation (Z-score >3.0) may participate only in only intensity class IA sports (billiards, bowling, cricket, curling, golf, and riflery) (class IIb).
Patients who have undergone coarctation repair (surgery or trancatheter intervention) may participate in competitive sports that do not pose a danger of bodily collision (class IIb) and do not require high-intensity static exercise (classes IIIA, IIIB, and IIIC) after 3 months following the corrective procedure, if the criteria listed above are met, there is no aneurysm at the site of coarctation intervention, and there is no significant concomitant aortic valve disease.[22]
Patients with evidence of significant aortic dilation (Z score >3.0) or aneurysm formation (not yet of a size requiring surgical repair) may participate only in low-intensity (class IA and IB) sports (class IIb).
Patients with normal blood pressure, no residual coarctation, and a normal ascending aorta diameter can participate in all activities without restriction.
Patients with residual coarctation or a dilated ascending aorta are managed on a case-by-case basis. The degree of narrowing of the coarctation segment and dilatation of the ascending aorta dictates the level of sport activity.
Levels of intensity of static exercise are classified as follows[23] :
Levels of intensity of dynamic exercise are classified as follows[23] :
Examples of sports classifications in increasing level of static component with a low dynamic component [23]
Examples of sports classifications in increasing level of static component with a moderate dynamic component [23]
Examples of sports classifications in increasing level of static component with a high dynamic component [23]
The American College of Cardiology/American Heart Association recommends all patients with coarctation of the aorta (repaired or not) be monitored by a cardiologist.[24]
Patients should have undergone at least one magnetic resonance imaging (MRI) or angiographic study following repair of the coarctation.
Lifelong surveillance following surgical repair is mandatory.[25] Close surveillance and aggressive management are necessary for residual hypertension, heart failure or intracardiac disease, associated bicuspid aortic valve, recurrent coarctation of the aorta, or significant arm-leg blood pressure gradient at rest or with exercise.
Ascending aortic dilation in the presence of a bicuspid aortic valve, new or unusual headache from berry aneurysm formation, late dissection proximal or distal to the repair site, and aneurysm formation at the site of coarctation repair are late sequelae of this disease.
Endocarditis prophylaxis is indicated for the following[10] :
Endocarditis prophylaxis is notindicated for the following:
Recommendations for clinical evaluation and follow-up [24]
Class I recommendations are as follows:
Medical therapy management strategies
Management of hypertension includes first-line pharmacotherapy with beta blockers, angiotensin-converting enzyme inhibitors, or angiotensin-receptor blockers. Selection of beta blockers or vasodilators are based in part on the aortic root size, the presence of aortic regurgitation, or both.
Recommendations for interventional and surgical treatment
Class I recommendations are as follows:
Class IIb recommendation
Although stent placement for long-segment coarctation may be considered, its 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:
Class IIb recommendation
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.[24]
The ESC guidelines largely agree with the ACC/AHA recommendations (all level of evidence: C).[6]
Their class I recommendation is for intervention in all patients with a noninvasive pressure difference above 20 mm Hg between the upper and lower limbs, regardless of symptoms but with upper limb hypertension (>140/90 mm Hg in adults), abnomal exercise blood pressure response, or significant left ventricular hypertrophy.
Their class IIa recommendation indicates intervention should be considered in hypertensive patients with more than 50% aortic narrowing relative to the aortic diameter at the level of the diaphragm (as seen on MRI, CT scan, or invasive angiography), regardless of the pressure gradient.
Their class IIb recommendation indicates intervention may be considered in patients with more than 50% aortic narrowing relative to the aortic diameter at the level of the diaphragm (as seen on MRI, CT scan, or invasive angiography), regardless of the pressure gradient and the presence of hypertension.
No specific medications are used to treat coarctation of the aorta because it is a mechanical obstruction. In the neonate, management of concomitant congestive heart failure may include prostaglandin E1 to maintain patency of the ductus arteriosus. Beyond the neonatal period, management of congestive heart failure may include digoxin and diuretics.
Hypertension should be controlled by beta-blockers, angiotensin-converting enzyme inhibitors, or angiotensin-receptor blockers as first-line medications. The choice of beta-blockers or vasodilators may be influenced in part by the aortic root size, the presence of aortic regurgitation, or both.[24]
Clinical Context: Used to maintain patency of ductus arteriosus when cyanotic lesion or interrupted aortic arch presents in newborn. Most effective in premature infants.
This agent promotes vasodilatation by direct effect on the vasculature and smooth muscle of the ductus arteriosus.
Clinical Context: Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Its indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.
These agents increase the contractility of cardiac muscle in a dose-dependent manner (ie, positive inotropic effect).
Clinical Context: Commonly used diuretic with moderate diuretic potency.
These agents inhibit electrolyte reabsorption in the thick ascending limb of the loop of Henle, thus promoting diuresis.