Overview
Definition:
Coarctation of the aorta (CoA) is a congenital narrowing or constriction of the thoracic aorta, typically occurring distal to the origin of the left subclavian artery.
Epidemiology:
It is one of the more common congenital heart defects, accounting for approximately 5-8% of all cases
Prevalence is estimated to be 1 in 2,500 to 1 in 5,000 live births
It is more common in males and is often associated with other cardiac anomalies, such as bicuspid aortic valve (up to 50-85% of cases), ventricular septal defects, and patent ductus arteriosus.
Clinical Significance:
CoA is a significant cause of cardiovascular morbidity and mortality in children and adults if left untreated or diagnosed late
The discrepancy in blood pressure between the upper and lower extremities is a hallmark sign, leading to distinct clinical manifestations and requiring timely intervention to prevent long-term complications such as heart failure, stroke, and premature atherosclerosis.
Clinical Presentation
Symptoms:
Neonatal presentation: Severe heart failure, poor feeding, irritability, weak pulses in lower extremities
Infantile presentation: Tachypnea, poor growth, fatigue, intermittent claudication in legs
Older children/adults presentation: Hypertension in upper extremities, headaches, epistaxis, syncope, leg cramps, cold extremities, murmur
Asymptomatic until adulthood is also common.
Signs:
Upper extremity hypertension with lower extremity hypotension or absence of palpable pulses
Brachial-femoral pulse delay
Palpable systolic thrill over the suprasternal notch or left interscapular region
A systolic ejection murmur, often heard best in the left interscapular area, may radiate to the back
Left ventricular hypertrophy on ECG
Wide pulse pressure in upper extremities.
Diagnostic Criteria:
Diagnosis is primarily based on clinical findings of differential blood pressure and pulse deficits, confirmed by imaging
No specific laboratory diagnostic criteria exist, but investigations help confirm the diagnosis and assess severity.
Diagnostic Approach
History Taking:
Focus on symptoms of heart failure in neonates/infants
Inquire about poor feeding, irritability, and delayed development
For older children and adults, ask about headaches, epistaxis, leg claudication, syncope, and family history of heart disease
Ask about associated syndromes like Turner syndrome.
Physical Examination:
Careful palpation of all peripheral pulses, comparing upper and lower extremities for strength and timing
Accurate blood pressure measurement in both arms and one leg
Auscultation for murmurs, gallops, and other abnormal heart sounds
Assessment for signs of heart failure and end-organ damage.
Investigations:
Echocardiography: The primary non-invasive diagnostic tool to visualize the coarctation, assess its severity, and identify associated anomalies
Transesophageal echocardiography (TEE) may be used for better visualization
Cardiac Catheterization: Invasive assessment of pressure gradients across the coarctation and assessment of coronary arteries, particularly in older patients
Angiography provides detailed anatomical information
MRI/CT Angiography: Useful for detailed anatomical assessment, especially in complex cases or for pre-operative planning, and to assess collateral circulation
ECG: May show left ventricular hypertrophy
Chest X-ray: May reveal cardiomegaly and characteristic "figure-3" sign due to dilated subclavian artery and post-stenotic dilation.
Differential Diagnosis:
Other causes of hypertension in children: Renal artery stenosis, pheochromocytoma, essential hypertension
Other causes of weak lower extremity pulses: Peripheral vascular disease, trauma
Patent ductus arteriosus (PDA) with differential pressures
Interrupted aortic arch
Hypoplastic left heart syndrome (HLHS) with severe outflow tract obstruction.
Management
Initial Management:
For neonates with severe coarctation and heart failure, initial management focuses on medical stabilization
Prostaglandin E1 infusion is crucial to maintain ductal patency and improve systemic circulation until surgical repair can be performed
Diuretics (e.g., furosemide) are used to manage fluid overload and heart failure
Oxygen therapy if needed.
Medical Management:
Long-term medical management is essential, particularly in those with residual gradients or hypertension post-repair
Antihypertensive medications such as beta-blockers, ACE inhibitors, or ARBs are used
Careful blood pressure monitoring is paramount.
Surgical Management:
Surgical repair is indicated for symptomatic infants and older children/adults with significant pressure gradients (>20 mmHg) or evidence of end-organ damage
Options include: Resection and end-to-end anastomosis (most common for discrete coarctation), Patch aortoplasty (for longer or more complex coarctations), Extra-anatomic bypass (e.g., subclavian flap aortoplasty, Gore-Tex graft)
Angioplasty (balloon or stenting) may be considered for recurrent coarctation or in specific adult cases, though surgery is often preferred for primary repair.
Repair Timing:
Repair is typically performed in the neonatal period for symptomatic neonates to prevent heart failure
Elective repair in asymptomatic infants or older children is usually recommended between 3-12 months of age to minimize the risk of long-term sequelae
Delaying repair in asymptomatic patients with significant gradients can lead to irreversible end-organ damage and increased surgical risk
However, the timing must be individualized based on severity, associated anomalies, and presence of symptoms.
Complications
Early Complications:
Surgical complications: Bleeding, infection, vocal cord paralysis (recurrent laryngeal nerve injury), chylothorax, phrenic nerve injury
Residual or recurrent coarctation
Aortic dissection or rupture
Hemorrhage
Cardiac arrest.
Late Complications:
Hypertension (persistent or recurrent)
Recurrent coarctation
Aortic aneurysm formation
Endocarditis
Stroke
Congestive heart failure
Premature atherosclerosis
Myocardial infarction
Aortic valve insufficiency if bicuspid aortic valve is present.
Prevention Strategies:
Early diagnosis and timely surgical intervention
Aggressive management of hypertension post-repair
Regular long-term follow-up with a cardiologist
Prophylaxis against infective endocarditis when indicated
Careful surgical technique to minimize injury to surrounding structures.
Prognosis
Factors Affecting Prognosis:
Age at repair (earlier is better), severity of coarctation, presence and type of associated cardiac anomalies, quality of surgical repair, and presence of residual hypertension or gradient post-repair
Associated genetic syndromes (e.g., Turner syndrome) can impact prognosis.
Outcomes:
With timely and successful repair, the long-term prognosis is generally good, with most patients achieving a normal lifespan
However, lifelong monitoring for hypertension and other cardiovascular sequelae is necessary
Patients with significant unrepaired or recurrent coarctation have a considerably poorer prognosis.
Follow Up:
Lifelong follow-up with a cardiologist is essential
This includes regular clinical assessment, blood pressure monitoring, echocardiography to assess for residual/recurrent coarctation and valvular function, and potentially cardiac catheterization or angiography if indicated
Emphasis on lifestyle modifications and adherence to antihypertensive medications is crucial.
Key Points
Exam Focus:
The classic finding of significant upper vs
lower extremity blood pressure discrepancy is paramount
Recognition of associated cardiac anomalies, particularly bicuspid aortic valve
Understanding the indications and timing of surgical repair
Knowledge of common complications like hypertension and recurrent coarctation.
Clinical Pearls:
Always measure blood pressure in both arms and at least one leg in any child presenting with hypertension or unexplained syncope
A palpable pulse delay between brachial and femoral arteries is highly suggestive
Consider coarctation in any infant with unexplained heart failure and weak lower extremity pulses.
Common Mistakes:
Failing to adequately assess lower extremity pulses or blood pressure, leading to delayed diagnosis
Inadequate management of post-repair hypertension
Misinterpreting echocardiographic findings or delaying referral for surgical intervention in symptomatic patients
Over-reliance on imaging without considering the clinical presentation.