Discrete narrowing of the aortic isthmus producing upper-extremity hypertension, weak femoral pulses, and rib notching.
Also known as: coarctation, aortic coarctation, CoA
Overview
Congenital narrowing of the aorta, most commonly located just distal to the origin of the left subclavian artery at the insertion of the ductus arteriosus (juxtaductal). Less commonly, the narrowing is more diffuse (tubular hypoplasia) or located proximal to the left subclavian artery.
Epidemiology
~5-8% of congenital heart disease. Male predominance ~2:1. Strong association with bicuspid aortic valve (50-85% of coarctation patients) and Turner syndrome (~10% of females with Turner have coarctation). Also associated with PDA, VSD, mitral valve abnormalities (Shone complex).
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Family history of coarctation or other left-sided obstructive lesions
Maternal exposures: rubella, alcohol
Other CHD: PDA, VSD, hypoplastic left heart spectrum, Shone complex
Pathophysiology
Fixed mechanical obstruction at the aortic isthmus elevates upper-body (above the coarctation) systolic pressure and reduces lower-body pressure, producing characteristic pulse and blood pressure differentials. Chronic afterload increase drives LV hypertrophy. Collateral circulation develops over years via intercostal, internal mammary, and scapular arteries, causing classic rib notching on CXR. In critical neonatal coarctation, the lower body is dependent on right-to-left flow through the PDA; ductal closure precipitates shock.
Clinical presentation
Symptoms
Neonates with critical coarctation: lower body shock, oliguria, metabolic acidosis as the PDA closes (typically days 1-2 of life)
Older children/adults: headaches, epistaxis, hypertension, leg claudication or fatigue with exertion, cold lower extremities
Asymptomatic and discovered on routine examination with arm-leg BP discrepancy
Signs / physical exam
Systolic blood pressure differential ≥20 mmHg between right arm and lower extremity (with arm > leg) — hallmark finding
Diminished, delayed, or absent femoral pulses (radio-femoral delay) compared to upper extremity
Mid-systolic murmur audible at the left infraclavicular area and over the back (especially interscapular)
Bicuspid aortic valve ejection click in many patients
Visible or palpable collateral arteries along the chest wall in adults
Classic findings
Hypertension in the upper extremities with delayed and weak femoral pulses; rib notching of the posterior 3rd-8th ribs on CXR; '3 sign' (figure-of-3) on CXR from pre- and post-stenotic dilation.
Differential diagnosis
Essential hypertension — Equal BP in arms and legs; consider in young adult with HTN — checking 4-extremity pressures is screening
Renovascular hypertension — Abdominal bruit, renal artery duplex or CTA; equal BP in arms vs legs
Genetic testing for Turner syndrome (karyotype) in females with coarctation
Imaging
Four-extremity blood pressure measurement — screening with right arm vs right leg
Transthoracic echocardiography — visualizes coarctation, gradient (typically >20 mmHg significant), associated bicuspid aortic valve, LV size and function
Cardiac MRI or CT angiography — preferred imaging for adolescents and adults; defines coarctation anatomy, collaterals, isthmus dimensions, and post-repair recoarctation
ECG: LVH in older patients; RVH in neonates
CXR: '3 sign' on the aortic shadow and rib notching of the posterior 3rd-8th ribs (rib notching is uncommon before age 4-5 because collaterals require time to develop)
Diagnostic algorithm
Finding
Expected in Coarctation
Arm BP vs leg BP
Arm > leg by ≥20 mmHg (systolic)
Femoral pulses
Diminished, delayed, or absent compared to brachial
Murmur
Mid-systolic at left infraclavicular area and over the back
Associated lesion
Bicuspid aortic valve in 50-85%
Syndrome
Turner syndrome (~10% have coarctation)
CXR (older child / adult)
Rib notching, '3 sign' on aortic shadow
First-line therapy (neonate)
PGE1 to maintain PDA, then surgical repair
First-line therapy (older patient)
Balloon angioplasty ± stent (or surgical repair)
Coarctation of the aorta — diagnostic pearls and approach to treatment.
Treatment
First-line
Critical neonatal coarctation: IV prostaglandin E1 (alprostadil) to maintain ductal patency, supportive care with inotropes as needed, then surgical repair (end-to-end anastomosis or subclavian flap aortoplasty) within days
Older children and adults with significant coarctation (gradient ≥20 mmHg or anatomic narrowing with upper-extremity HTN or LVH): percutaneous balloon angioplasty with or without stenting (preferred in older children and adults) OR surgical repair, depending on anatomy and institutional expertise
Antihypertensive therapy preoperatively and for postoperative residual hypertension: beta-blockers (atenolol, metoprolol) are commonly first-line; avoid drugs that drop preload excessively in critical neonatal forms
Second-line / adjunct
Lifelong cardiology follow-up after repair — surveillance for recoarctation, aneurysm at the repair site, bicuspid aortic valve disease, and residual hypertension
ACE inhibitors or ARBs for persistent hypertension after repair
Endocarditis prophylaxis indicated within the first 6 months after repair with prosthetic material, or indefinitely if residual defect remains adjacent to prosthetic material
Complications
Heart failure (neonatal or chronic)
Persistent or recurrent hypertension even after successful repair (lifelong cardiovascular risk)
Stroke (berry aneurysms of the circle of Willis occur in ~10% of patients and confer increased risk of hemorrhagic stroke)
Aortic dissection or rupture (especially with associated bicuspid valve aortopathy)
Recoarctation and aneurysm formation at the repair site
Premature coronary artery disease
Infective endocarditis (particularly with bicuspid aortic valve)
PANCE pearls
Always check four-extremity blood pressures in any young hypertensive patient — a ≥20 mmHg systolic differential (arm > leg) is the classic screening clue.
Bicuspid aortic valve coexists with coarctation in 50-85% — every patient with one should be evaluated for the other.
Turner syndrome: ~10% have coarctation; obtain echocardiography in all newly diagnosed patients.
Rib notching is from dilated tortuous intercostal collaterals eroding the undersurface of the ribs; usually visible only after age 4-5.
Berry aneurysms of the circle of Willis are more prevalent in coarctation; consider screening MRA in adults, especially with refractory hypertension or focal neurologic symptoms.
References
AHA/ACC 2018 — 2018 AHA/ACC Guideline for the Management of Adults with Congenital Heart Disease (Stout et al., Circulation 2019)
AHA Scientific Statement — Cardiovascular Health in Turner Syndrome (Silberbach et al., Circulation 2018)
ESC 2020 — 2020 ESC Guidelines for the Management of Adult Congenital Heart Disease (Baumgartner et al., Eur Heart J 2021)
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