DESCRIPTION 
- Coarctation of the aorta is defined by a narrowing of the proximal thoracic aorta, resulting in obstruction to systemic blood flow.
- Typically discrete narrowing in the proximal descending aorta opposite to the insertion of the ductus arteriosus (juxta-ductal), although it may involve a longer segment or be associated with tubular hypoplasia of the aortic transverse arch. Coarctation involving the abdominal descending aorta is rare.
- Bicuspid aortic valve is present in 50–70% of patients.
EPIDEMIOLOGY
- Age: Severe cases present in the newborn period; significant proportion of less-severe forms diagnosed in childhood or adolescence
- Male = Female: 1.3–1.7
Incidence
- 6–8% of patients with congenital heart disease
- Occurs in 1/3,000–4,000 live births
RISK FACTORS
None
Genetics
- Most cases sporadic, with multifactorial genetic influence
- Increased incidence in Turner syndrome, with 35% affected
PATHOPHYSIOLOGY
- Increased LV afterload may cause systolic and diastolic LV dysfunction.
- "Critical" coarctation causes LV systolic dysfunction, CHF, hypotension, and metabolic acidosis in the 1st mo of life.
- In less-severe forms with later diagnosis, collateral circulation bypassing the narrowing often develops, masking degree of obstruction. Mild coarctation without collaterals is also common.
- Abnormal vascular physiology with upper extremity systemic HTN
ETIOLOGY
- Left heart obstructive defects that diminish fetal LV output will cause coarctation by increasing ductal flow and decreasing LV output, resulting in hypoplasia of the isthmus. Frequency of associated bicuspid aortic valve supports this concept.
- Discrete forms of coarctation may occur due to migration of smooth muscle cells from the ductus arteriosus into the juxtaductal aorta with constriction and narrowing of the aortic lumen associated with postnatal ductal constriction.
COMMONLY ASSOCIATED CONDITIONS
- Cardiac: Bicuspid aortic valve, ventricular septal defect, congenital mitral valve stenosis; may be a component of complex congenital heart disease
- Extracardiac: Turner syndrome; abnormalities of musculoskeletal, genitourinary, gastrointestinal or respiratory systems; berry aneurysms in the circle of Willis
Outline
Signs and symptoms depend on severity of aortic narrowing.
History
- Newborn infants with critical coarctation:
- Often catastrophic illness with rapid or labored breathing, poor feeding, lethargy.
- A ventricular septal defect is often present.
- Children or adolescents are often asymptomatic.
Physical Exam
- Absent or feeble femoral pulse with normal upper extremity pulses, upper extremity HTN with normal or low BP of the lower extremities. With critical coarctation, tachycardia, hypotension, poor peripheral perfusion, gallop rhythm
- Simultaneous measurement of upper and lower extremity BP is mandatory when coarctation is suspected.
DIAGNOSTIC TESTS & INTERPRETATION
- EKG in newborn infants shows prominent RV forces. In longstanding coarctation, LV hypertrophy or strain may be noted.
- Normal EKG does not exclude the diagnosis of coarctation.
Lab
Metabolic acidosis with critical coarctation and low cardiac output
Imaging
- CXR in infancy may show cardiomegaly. In older children, localized indentation of the aorta (3 sign) and rib notching may be seen.
- Echo diagnostic in most cases, especially infants and young children. The aortic arch is visualized; the isthmic region is seen well on younger patients. Associated bicuspid aortic valve will be recognized, and status of LV is assessed. Descending aortic Doppler tracing shows elevated velocity of flow during diastole.
- MRI useful if evaluation incomplete by echo, especially in older children or adolescents.
Diagnostic Procedures/Surgery
Cardiac catheterization, although rarely needed, may be carried out in complex cases with associated defects.
DIFFERENTIAL DIAGNOSIS
Abdominal coarctation: A complex lesion is often associated with renal artery stenosis.
Outline
ADDITIONAL TREATMENT
General Measures
Treatment is surgical or transcatheter, and depends on severity and age of presentation.
Referral
An infant or child with diminished femoral pulses or upper extremity HTN with low or normal lower extremity BP should be referred to a pediatric cardiologist. Differences in BP may be obscured in the presence of severe heart failure and decreased cardiac output.
SURGERY
- Indicated for significant obstruction to flow. Usually involves resection of involved aortic segment with end-to-end anastomosis. More extensive reconstruction may be necessary for associated tubular hypoplasia of the transverse aortic arch.
- Percutaneous transcatheter stenting of narrowed segment possible in older children and adolescents for discrete coarctation is effective. Limited long-term data available for this newer therapy.
- Transcatheter balloon angioplasty has been utilized, but may be associated with a higher incidence of aortic aneurysms.
IN-PATIENT CONSIDERATIONS
Admission Criteria
Low cardiac output, CHF
Discharge Criteria
Recovery after surgical or transcatheter treatment
Outline
FOLLOW-UP RECOMMENDATIONS
- Lifelong follow-up with a cardiologist with experience in congenital heart defects
- Follow-up includes measurement of upper and lower extremity BP to identify recurrent coarctation and evaluation of associated cardiac defects. Persistent HTN without residual coarctation may be found, especially if repair was carried out at an older age.
Patient Monitoring
Upper and lower extremity BP monitored periodically following repair for persistent systemic HTN and recurrent coarctation
DIET
Regular; salt-restriction for significant persistent HTN
PATIENT EDUCATION
Activity is unrestricted following successful repair.
PROGNOSIS
- Excellent, with normal expected growth and development and minimal or no restrictions to activity
- Follow-up required: Right arm BP, upper and lower extremity BP gradient, mitral and aortic valve status, and other conditions
- HTN and premature coronary disease can become an issue in adult life.
COMPLICATIONS
- Recurrent coarctation in 6–20% following repair in infancy and is treatable with balloon angioplasty or surgery
- Risk of persistent or late HTN in 10%, especially when repair delayed
- Aortic aneurysms at site of repair may develop, usually following use of prosthetic material for repair or following balloon angioplasty for native coarctation.
- Risk of bacterial endocarditis persists following repair but routine antibiotic prophylaxis is no longer indicated.
Outline
CODES
ICD9
747.10 Coarctation of aorta (preductal) (postductal)
SNOMED
7305005 coarctation of aorta (disorder)