Basics
Description
- Discrete stenosis of the upper thoracic aorta, usually just opposite the site of insertion of the ductus arteriosus (juxtaductal). A segment of tubular hypoplasia and/or a remnant of ductal tissue give rise to a prominent posterior infolding ("the posterior shelf"�).
- The hemodynamic lesion is most often discrete but may be a long segment or tortuous in nature. It is usually juxtaductal but may occur in other sites (i.e., the abdominal aorta). The prevalence of other associations (bicuspid aortic valve) and long-term complications (hypertension) indicate that this lesion may be part of a broader spectrum arteriopathy and/or endothelial disorder.
Epidemiology
Prevalence
- ~6-8% of patients with congenital heart disease have coarctation.
- Male > female (1.5-4.0:1)
Risk Factors
Genetics
- Multifactorial: occurs in 35% of patients with Turner syndrome (XO)
- Has been described in cases of monozygotic twins
- Many studies document the prevalence of a microdeletion at 22q11 in patients with arch anomalies and ventricular septal defects.
Pathophysiology
- Decreased systemic blood flow to lower body after ductal closure
- Increased afterload to left ventricle (LV) causes LV hypertrophy. Relative underperfusion of the renal vessels, baroreceptors, and multiple other mechanisms combine to induce compensatory hypertension.
- If the coarctation is severe, LV dysfunction and congestive heart failure (CHF) result, with low cardiac output and increased LV end-diastolic pressure.
- Decreased myocardial perfusion may be present in cases of very low output.
Diagnosis
History
There are 2 typical patterns for the clinical presentation of coarctation: �
- An infant with CHF or shock: Typically precipitated by ductal closure, this presentation is more common in infants with coarctation and other intracardiac malformations (20-30%):
- Respiratory distress (dyspnea/tachypnea)
- Poor feeding
- Pallor
- Diaphoresis
- Poor weight gain
- Oliguria
- An otherwise asymptomatic child or adolescent with systolic hypertension and/or a heart murmur (70-80%)
- Lower extremity claudication
- Headaches
Physical Exam
- Tachypnea and tachycardia
- Discrepant arterial pulses and systolic blood pressure (BP) in the upper and lower extremities
- Weak, "thready"� pulses
- Grade 2-3/6 systolic ejection murmur
- Gallop rhythm in an infant with CHF
- Ejection click of a bicuspid aortic valve
- The most important finding is decreased or absent lower extremity pulses. Are pulses present? Is there a delay between the brachial and femoral pulses?
- Heart murmur: best heard at the upper left sternal border, at the base, and radiating to the left interscapular area posteriorly
- An infant with severe coarctation and a patent ductus arteriosus (PDA) may have "differential cyanosis."� The lower part of the body appears cyanotic because the descending aortic flow is provided by the right ventricle (RV) through the PDA (check postductal saturation).
Alert
- The most reliable clinical findings to diagnose native, residual, or recurrent coarctation are the presence of pressure differences in the upper and lower extremities and decreased or absent femoral pulses. Palpable pulses do not exclude coarctation. What one palpates is pulse pressure, not absolute systolic pressure.
- 4-extremity BP measurement is very important in assessing infants and children with possible congenital heart disease. Proper cuff size must be used.
- Bowel ischemia can be present in the ill patient, and emesis or poor feeding are hallmark signs.
Diagnostic Tests & Interpretation
Lab
- Electrocardiogram: RV hypertrophy is usually present in symptomatic infants. The electrocardiogram is often normal in children. LV hypertrophy is apparent with more severe coarctation or longer standing coarctation, particularly in older children.
- Blood tests: In the patient presenting in extremis, management, initial therapy, and timing of surgery can be guided by arterial blood gas analyses and markers of end organ dysfunction.
Imaging
- Chest x-ray: in the infant, moderate to severe cardiomegaly with increased pulmonary vascular markings (PVMs). In an asymptomatic child, the heart size is often normal, with normal PVMs. Rib notching may be seen in older children secondary to dilated intercostal collateral vessels.
- Echocardiography: localization, degree of coarctation, and associated findings (PDA, arch hypoplasia, other defects); assessment of associated left-sided obstruction: mitral valve abnormality, LV outflow obstruction, and aortic stenosis (bicuspid aortic valve)
- Magnetic resonance imaging: clearly defines the location and severity of coarctation; useful for serial postoperative follow-up (especially aortic aneurysms)
Diagnostic Procedures/Other
- Cardiac catheterization and angiography: usually not indicated unless there are further questions to be answered and/or a planned intervention
Differential Diagnosis
- Other left-sided heart obstructive lesions
- Hypoplastic left heart syndrome
- Cardiomyopathy and/or myocarditis
- Critical aortic stenosis (aortic obstruction to a degree that adequate systemic perfusion depends on patency of the ductus arteriosus)
- Sustained tachyarrhythmia
- Shock from sepsis, metabolic disease, or other entities
Treatment
General Measures
- For the sick neonate who presents with severe CHF or shock (ductal-dependent systemic blood flow):
- Alprostadil (PGE1) prostaglandin infusion: 0.05-0.1 mcg/kg/min (anticipating adverse effects, including apnea)
- Inotropic support: Dopamine 3-5 mcg/kg/min
- Diuretics for pulmonary venous hypertension or pulmonary edema
- Surgical intervention should follow as soon as possible.
- For the asymptomatic child, elective repair and assessment for systemic hypertension are appropriate; however, aggressive antihypertensive pharmacotherapy is not indicated prior to surgical intervention.
- Other
- Interventional cardiology
- Percutaneous balloon angioplasty of native coarctation in infants and children is pursued in some centers. Others have concern about rates of recurrent stenosis, hypertension, aneurysm formation, and iliofemoral arterial injury.
- Use of vascular stents to relieve the area of stenosis, particularly in older children and adolescents, has provided an alternative to surgical intervention; may increase the need for reintervention in the future when compared to the surgical approach
Surgery/Other Procedures
- Infancy
- Surgical repair of severe coarctation and coarctation associated with intracardiac anomalies
- The surgical mortality rate for infants with coarctation and a large ventricular septal defect ranges from 5 to 15% and is higher for children with more complex intracardiac anomalies.
- Childhood
- Elective coarctation repair between ages 18 months and 3 years in asymptomatic children without severe upper extremity hypertension. Later repair is associated with an increased risk of sustained hypertension and other late complications.
- Types of surgical repair: end-to-end anastomosis, subclavian flap aortoplasty, prosthetic patch aortoplasty, bypass graft
Ongoing Care
Follow-up Recommendations
Patient Monitoring
- Reexamine every 12 months with 4-extremity pulse and BP assessment.
- Residual or recurrent coarctation occurs most commonly in those patients requiring repair in early infancy and can depend on the method of intervention (e.g., higher incidence with patch aortoplasty and coarctation ridge resection); most centers delay percutaneous balloon angioplasty of residual or recurrent lesions until 2 months postoperatively.
- Persistent systemic hypertension: most common in patients whose coarctation repair is delayed beyond late childhood
- Aortic aneurysm formation
- Intracranial aneurysms and/or cerebrovascular accidents
- May have hypertension with exercise, even if normotensive at rest
- Exercise-induced hypertension without anatomic stenosis may respond to beta-blocker therapy.
Prognosis
- Untreated coarctation has a poor natural history with the onset of CHF, especially in those patients with other intracardiac malformations. Claudication is common in older children with previously undiscovered coarctation. Generally, the short-term prognosis following successful intervention for isolated coarctation in infancy or childhood is excellent. Procedure-related mortality in every modern series is very near zero.
- Clinical conditions that may affect long-term prognosis after repair of coarctation include the following:
- Residual or recurrent coarctation
- Hypertension (rest and exercise)
- Aortic aneurysm (associated with repair technique)
- Associated intracardiac lesions
- Intracranial aneurysms
- Occurrence or progression of aortic valve disease
- Premature coronary arterial and cerebrovascular disease
- Associated lesions
- Bicuspid aortic valve
- Ventricular septal defect
- Valvar or subvalvar aortic stenosis
- Mitral stenosis: often associated with structural mitral valve abnormalities (i.e., supravalvar mitral ring, thickening of mitral leaflet, single papillary muscle with parachute deformity, or short dysplastic chordae tendineae)
- Shone syndrome: multiple left-sided obstructive lesions, including supravalvar mitral ring, parachute mitral valve, subaortic obstruction, and coarctation
- Berry aneurysm of the circle of Willis
- Renal artery stenosis associated with abdominal coarctation
- Congenital diaphragmatic hernia
Complications
- Shock, if severe untreated obstruction
- CHF, if severe untreated obstruction
- Systemic hypertension, before and after intervention
- Intracranial aneurysms
- Mesenteric ischemia
- Paraplegia
- Postoperative complications
- Bleeding
- Postcoarctectomy syndrome/mesenteric ischemia
- Paradoxical hypertension
- Spinal cord ischemia (0.4%)
- Residual coarctation
- Chylothorax
- Stridor
- Diaphragm paralysis
- Aortic aneurysm or dissection
- Paralysis
Additional Reading
- Carr �JA. The results of catheter-based therapy compared with surgical repair of adult aortic coarctation. J Am Coll Cardiol. 2006;47(6):1101-1107. �[View Abstract]
- Celermajer �DS, Greaves �K. Survivors of coarctation repair: fixed but not cured. Heart. 2002;88(2):113-114. �[View Abstract]
- Cowley �CG, Orsmond �GS, Feola �P, et al. Long-term randomized comparison of balloon angioplasty and surgery for native coarctation of the aorta in childhood. Circulation. 2005;111(25):3453-3456. �[View Abstract]
- Rosenthal �E. Coarctation of the aorta from fetus to adult: curable condition or lifelong disease process? Heart. 2005;91(11):1495-1502. �[View Abstract]
- Shah �L, Hijazi �Z, Sandhu �S, et al. Use of endovascular stents for the treatment of coarctation of the aorta in children and adults: immediate and midterm results. J Invasive Cardiol. 2005;17(11):614-618. �[View Abstract]
- Toro-Salazar �OH, Steinberger �J, Thomas �W, et al. Long-term follow-up of patients after coarctation of the aorta repair. Am J Cardiol. 2002;89(5):541-547. �[View Abstract]
Codes
ICD09
- 747.10 Coarctation of aorta (preductal) (postductal)
ICD10
- Q25.1 Coarctation of aorta
SNOMED
- 7305005 Coarctation of aorta (disorder)
- 253675002 Juxtaductal aortic coarctation (disorder)
- 253679008 Abdominal aortic coarctation (disorder)
FAQ
- Q: When is the most appropriate time to perform surgical repair of simple coarctation?
- A: Recommendations vary regarding the age at which asymptomatic children (without severe upper extremity hypertension) should undergo intervention. Advances in technique no longer require patients to be "grown"� to a threshold size or weight, and there is increasing evidence that severity and incidence of late complications correlate directly with older age at repair. Although some authors mention 3-5 years of age, others recommend repair as early as 18 months to 2 years of age.
- Q: What is the incidence of systemic hypertension after surgical repair of coarctation?
- A: Greatly depends on age at repair, surgical method or technique, length of follow-up interval, and how one defines or measures hypertension. In no situation is the answer zero, and this important complication is one of several reasons patients require lifelong detailed follow-up. 1 year after a technically perfect repair via resection with end-to-end anastomosis, the patient operated on in early childhood is unlikely to have hypertension at rest. However, 20 years further along, a patient of older age at repair is quite likely to have significant hypertension on exercise stress testing.