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).
Try two board-style Coarctation of the Aorta questions
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Question 1CardiovascularEasy
A 17-year-old boy is evaluated for headaches and a blood pressure of 162/94 mm Hg found at a sports physical. He reports leg fatigue when running. On exam, the radial pulses are strong, but the femoral pulses are diminished and delayed relative to the radial pulses. Blood pressure is 158/92 mm Hg in the right arm and 118/70 mm Hg in the right leg. A mid-systolic murmur is heard over the left infraclavicular region and the interscapular area of the back. Which of the following is the most likely diagnosis?
ATakayasu arteritis
BEssential hypertension
CCoarctation of the aorta
DRenovascular hypertension
Reveal answer & full explanation
Correct answer: C — Coarctation of the aorta
ATakayasu arteritis
BEssential hypertension
CCoarctation of the aorta✓
DRenovascular hypertension
Why Coarctation of the aorta is correct
The hallmark is upper-extremity hypertension with a systolic arm-to-leg differential ≥20 mm Hg (here 158 vs 118), arm pressure greater than leg.
Diminished and delayed femoral pulses (radio-femoral delay) reflect the fixed obstruction at the aortic isthmus, classically just distal to the left subclavian artery.
A mid-systolic murmur heard over the left infraclavicular area and interscapularly over the back is the classic auscultatory finding; coarctation is a leading cause of secondary hypertension in adolescents and is strongly linked to bicuspid aortic valve.
Why the others are wrong
Essential hypertension is the most common cause of hypertension overall, but it produces equal pressures in the arms and legs with normal, symmetric femoral pulses; it does not cause radio-femoral delay or an interscapular murmur.
Renovascular hypertension is secondary hypertension from renal artery stenosis that presents with an abdominal bruit and equal arm-versus-leg pressures, not a lower-extremity pulse and pressure deficit.
Takayasu arteritis is a large-vessel vasculitis that classically causes arm-to-arm BP differentials, absent upper-extremity pulses, and elevated inflammatory markers, typically in young women; it does not produce the isolated arm-greater-than-leg differential with an interscapular murmur seen here.
Question 2CardiovascularMedium
A 17-year-old boy is evaluated for hypertension found at a sports physical, with a right-arm blood pressure of 158/92 mm Hg. He reports occasional headaches and leg fatigue when running. On examination, the femoral pulses are diminished and delayed relative to the brachial pulses, and a mid-systolic murmur is heard over the left interscapular area of the back. A coarctation of the aorta is suspected. Which of the following is the most appropriate next diagnostic test?
ATransthoracic echocardiography imaging
BFour-limb blood pressure measurement
CPosteroanterior chest radiography
DCardiac MR angiography of the aorta
Reveal answer & full explanation
Correct answer: B — Four-limb blood pressure measurement
ATransthoracic echocardiography imaging
BFour-limb blood pressure measurement✓
CPosteroanterior chest radiography
DCardiac MR angiography of the aorta
Why Four-limb blood pressure measurement is correct
It is the simplest, fastest, noninvasive bedside step and directly documents the suspected pathophysiology before any advanced imaging.
A systolic gradient of 20 mm Hg or more between the arm and the leg (arm greater than leg) is the hallmark finding that confirms a hemodynamically significant coarctation.
In any young hypertensive patient with diminished or delayed femoral pulses, four-limb pressures are the standard initial screen.
Why the others are wrong
Transthoracic echocardiography imaging visualizes the isthmus, gradient, and associated bicuspid aortic valve and is the usual first imaging study, but it follows documentation of the arm-leg pressure gradient rather than preceding it.
Cardiac MR angiography of the aorta best defines coarctation anatomy, collaterals, and isthmus dimensions in adolescents and adults, yet it is the later confirmatory step, not the immediate next test.
Posteroanterior chest radiography may show inferior rib notching from intercostal collaterals or a figure-3 aortic contour, but these signs are insensitive and are frequently absent in adolescents, so a normal film neither excludes coarctation nor documents the arm-leg gradient.
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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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