Key Facts

Coarctation of the aorta is a congenital narrowing of the aorta, most commonly at the isthmus just distal to the origin of the left subclavian artery, near the insertion of the ligamentum arteriosum (ductus arteriosus remnant).

Epidemiology

• Accounts for ~5-8% of congenital heart defects
• Male:female ratio ~2:1 (except in Turner syndrome)
• Incidence: ~3-4 per 10,000 live births
• Associated with Turner syndrome (45,X) — coarctation occurs in ~10-15% of Turner patients

Aetiology

• Congenital: abnormal development of the aortic arch
• Two theories: (1) ectopic ductal tissue in aortic wall contracts after birth; (2) reduced aortic flow during fetal life (flow theory)
• Strong association with bicuspid aortic valve (~50-80% of coarctation patients have BAV)
• Other associations: VSD, PDA, mitral valve abnormalities, Turner syndrome, intracranial (Berry) aneurysms

Pathophysiology

• Narrowing creates pressure gradient → proximal hypertension (upper body) + distal hypotension (lower body)
• LV pressure overload → concentric LVH → heart failure
• Collateral circulation develops via intercostal, internal mammary, and scapular arteries (causes rib notching)
• Long-term complications: systemic hypertension (even after repair), premature coronary artery disease, aortic dissection, Berry aneurysm rupture

Neonatal (severe/critical coarctation):

• Duct-dependent systemic circulation: lower body perfusion depends on PDA
• Ductal closure → acute cardiovascular collapse, shock, metabolic acidosis

Neonatal Presentation (Critical Coarctation)

• Presents at 1-2 weeks when ductus closes
• Cardiovascular collapse, shock, metabolic acidosis
• Poor feeding, tachypnoea, grey appearance
• Absent or weak femoral pulses
• Emergency: requires prostaglandin E1 to reopen ductus

Older Children/Adults

• Often asymptomatic; discovered incidentally (hypertension, murmur)
• Headache (hypertension)
• Exertional leg claudication or fatigue
• Epistaxis
• Cold feet

Examination Findings

• Radio-femoral delay: diminished and delayed femoral pulses compared to radial
• Blood pressure differential: upper limb BP higher than lower limb by >20 mmHg
• Upper body hypertension with relatively hypotensive lower limbs
• Systolic murmur: heard over the left infraclavicular area, left axilla, and between the scapulae
• Visible/palpable collaterals around the scapulae
• Signs of associated BAV (ejection click, AS/AR murmurs)

Red Flags

• Neonatal shock with absent femoral pulses → emergency
• Unexplained hypertension in a young person → check femoral pulses
• Arm-leg BP differential >20 mmHg

Bedside

• Four-limb BP measurement: >20 mmHg systolic gradient between arms and legs
• Pulse assessment: radio-femoral delay, weak/absent femoral pulses
• ECG: LVH (concentric), may be normal in mild coarctation
• CXR: rib notching (ribs 3-8, bilateral), '3 sign' on barium swallow or PA film, LVH

Bloods

• U&Es: renal function (renal hypoperfusion)
• Blood gas (neonatal): metabolic acidosis in critical coarctation
• Chromosomal analysis: if Turner syndrome suspected (45,X)

Imaging

• Echocardiography: coarctation site and gradient, associated lesions (BAV, VSD, PDA), LV function
• CT angiography/MR angiography: gold standard for anatomy; shows site, extent, collaterals, associated aortic pathology
• Cardiac catheterisation: definitive gradient measurement; may be therapeutic (balloon angioplasty ± stenting)

Special Tests

• MRI brain: screen for Berry aneurysms (associated with coarctation)
• Ambulatory BP monitoring: assess for residual hypertension post-repair

Non-pharmacological

• Critical neonatal coarctation: emergency stabilisation
  • Prostaglandin E1 (alprostadil) infusion: reopen ductus to restore lower body perfusion
  • Ventilatory support, volume resuscitation, correct acidosis

Pharmacological

• Antihypertensives: beta-blockers, ACEi/ARBs (post-repair or if mild coarctation in adults)
• Hypertension may persist even after successful repair (~25-50%)
• Pre-operative optimisation: correct shock, acidosis

Surgical/Interventional

Neonates/infants:

• Surgical repair: end-to-end anastomosis (preferred), subclavian flap repair, or extended end-to-end
• Performed via left lateral thoracotomy; operative mortality <2%

Older children/adolescents/adults:

• Balloon angioplasty ± stenting: standard for native or recurrent coarctation in older patients
• Covered stent placement: reduces risk of aortic wall injury
• Surgical repair: alternative if anatomy unfavourable for percutaneous approach

Referral Criteria

• All coarctation: congenital/paediatric cardiology referral
• Critical neonatal coarctation: immediate neonatal/cardiac surgery transfer
• Adults with coarctation: GUCH specialist
• Lifelong cardiology follow-up required post-repair

• Natural history without repair: mean survival ~35 years; death from heart failure, aortic dissection, endocarditis, or Berry aneurysm rupture
• Post-repair: >95% survival at 20 years
• Re-coarctation: ~5-10% after surgical repair; ~5-15% after balloon angioplasty
• Persistent hypertension: ~25-50% even after successful repair (especially if repaired after age 5)
• Lifelong surveillance needed: re-coarctation, aneurysm at repair site, aortic root dilatation (if BAV), Berry aneurysm screening
• BAV-related complications (AS, AR) may develop later in life

Associated Conditions

CXR Signs in Coarctation