Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Coarctation of the aorta
Paediatrics and child health · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Duct-dependent systemic collapse
Critical coarctation can become apparent as the arterial duct closes, causing grey colour, tachypnoea, weak femoral pulses, oliguria, metabolic acidosis, myocardial dysfunction and shock despite little cyanosis or a subtle murmur.
Action: Begin neonatal ABCDE resuscitation, call neonatal, paediatric cardiology and retrieval teams, obtain preductal and postductal saturations, four-limb pulses, blood gas, lactate, glucose, cultures and urgent echocardiography. Treat sepsis when plausible and start alprostadil through the regional duct-dependent pathway without waiting for imaging when clinical suspicion is high; use continuous monitoring, a dedicated line and an airway plan.
Overview
Recognise neonatal duct-dependent shock and later upper-body hypertension, confirm arch anatomy and associated disease, stabilise safely with prostaglandin when indicated, and provide lifelong surveillance after repair.
The narrowed segment is commonly juxtaductal, but hypoplasia may involve the transverse arch and isthmus. Anatomy ranges from discrete narrowing to long-segment interruption and determines operative technique.
Before birth, the duct supplies much of the descending aorta, masking obstruction. After birth, ductal constriction forces left-ventricular output through the narrowed arch and can abruptly reduce lower-body perfusion.
The newborn left ventricle faces high afterload while coronary and cerebral circulation may receive relatively preserved upper-body flow. Renal and mesenteric hypoperfusion creates oliguria, acidosis and multiorgan dysfunction.
Severe collapse can mimic sepsis, respiratory disease or metabolic illness and the conditions can coexist. Cultures and antibiotics should proceed when indicated, but pulse examination and echocardiography must not be omitted.
With milder obstruction, collateral arteries enlarge and sustain lower-body flow. The child may remain asymptomatic until hypertension is detected, while femoral pulses are delayed and a posterior thoracic murmur reflects collateral or turbulent aortic flow.
Practice
Two practice questions
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Paediatrics and child healthOriginal SBA
Neonatal coarctation collapse
A 6-day-old is lethargic and acidotic with weak femoral pulses, oliguria and a low but equal saturation in the right hand and foot. What is the most appropriate immediate pathway?
Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Right-arm pressure is preferred because the left subclavian artery can arise near or beyond the narrowing. Correct cuff size, calm conditions and repeated measures are necessary before interpreting a modest gradient.
Echocardiographic Doppler estimates velocity but can over- or underestimate anatomical severity depending on arch geometry, collaterals and ventricular function. Specialist interpretation integrates pulses, pressure, anatomy and ventricular response.
Alprostadil relaxes ductal smooth muscle and can restore descending-aortic flow while surgery is arranged. It is an emergency bridge rather than definitive treatment and can cause apnoea, hypotension and pyrexia.
Surgical options include resection with end-to-end or extended anastomosis, patch enlargement and selected subclavian flap procedures. Technique depends on age, arch hypoplasia, previous repair and associated intracardiac disease.
Catheter balloon treatment may relieve recurrent narrowing; stents support a larger vessel in suitable older patients but must accommodate growth and avoid branch-vessel or aortic-wall injury.
Hypertension can persist despite an excellent resting gradient because arterial stiffness, altered baroreflexes and exercise hypertension reflect a broader aortopathy. Ambulatory and exercise data may reveal burden missed in clinic.
Associated bicuspid aortic valve, VSD, Turner syndrome and other genetic diagnoses influence imaging and counselling. Future pregnancies in the family and the child's adult cardiovascular risks belong in long-term planning.
Key points
Coarctation is a congenital narrowing of the aorta, usually near the ductal insertion just beyond the left subclavian artery, causing upper-body pressure load and reduced lower-body flow.
Critical neonatal disease may depend on ductal flow to bypass the narrowing. Closure can precipitate shock after an initially normal examination and newborn screen.
Older children may present with right-arm hypertension, headaches, epistaxis, a systolic murmur over the left infraclavicular area or back, radiofemoral delay and reduced leg exercise capacity.
Examine simultaneous right brachial and femoral pulses, measure right-arm and leg blood pressure with correct cuffs, assess perfusion and palpate for collateral vessels; left-arm pressure can be misleading if the subclavian origin is involved.
Initial emergency tests are blood gas, lactate, renal and liver function, glucose, ECG and urgent paediatric echocardiography; do not delay stabilisation for a full imaging sequence.
Echocardiography defines the arch, gradient, duct, ventricular function and associated VSD or bicuspid aortic valve. MRI or CT maps the entire aorta in older children and during surveillance.
When duct-dependent obstruction is strongly suspected, start regional-protocol alprostadil and prepare for apnoea and hypotension; improving femoral pulses, lactate and acidosis indicate physiological response.
Aetiology
01
Arch developmental narrowing
Abnormal formation and growth of the fetal aortic arch produces discrete juxtaductal narrowing or broader arch hypoplasia.
02
Ductal tissue influence
Extension of ductal smooth muscle into the adjacent aortic wall may tighten the juxtaductal segment as the duct constricts after birth.
03
Genetic associations
Turner syndrome and selected congenital syndromes increase risk, while bicuspid aortic valve and other left-sided lesions commonly coexist.
04
Multifactorial sporadic disease
Most cases do not have a single proven inherited cause, although recurrence of congenital cardiac disease is above population background.
Pathophysiology
1
Upper-lower pressure separation
Obstruction raises proximal arterial pressure and ventricular afterload while lowering distal pulsatility and systemic organ perfusion.
2
Ductal bypass loss
Constriction of the fetal arterial duct removes an alternative route to the descending aorta and exposes critical neonatal obstruction.
3
Collateral adaptation
Intercostal and internal thoracic vessels enlarge over time, maintaining leg flow but generating murmurs and masking the resting gradient.
4
Persistent vascular dysfunction
Aortic wall abnormality, stiffness and altered pressure regulation can sustain hypertension even after the focal narrowing is repaired.
Clinical features and red flags
Collapsed newborn
Grey colour, lethargy, tachypnoea, weak femoral pulses, oliguria and acidosis develop as the arterial duct closes.
Pulse discrepancy
Right brachial upstroke precedes a weak or delayed femoral pulse; lower limbs may feel cool with prolonged refill.
Childhood hypertension
Upper-limb hypertension, headache or epistaxis with low leg pressure, leg fatigue and a back murmur suggests later diagnosis.
Cardiac examination
A left infraclavicular or interscapular systolic murmur, ventricular impulse or bicuspid-valve click may accompany the pulse findings.
Associated phenotype
Short stature, webbed neck or lymphoedema suggests Turner syndrome; a click may indicate bicuspid aortic valve.
Post-repair recurrence
New radiofemoral delay, resting or ambulatory hypertension and reduced exercise leg power indicate recurrent obstruction or vascular dysfunction.
Red flags requiring action
A previously well newborn developing poor feeding, lethargy, tachypnoea, oliguria or shock in the first days or weeks must have femoral pulses checked and critical coarctation considered.
Weak, absent or delayed femoral pulses, cool lower limbs or a reproducible right-arm to leg blood-pressure gradient indicates important arch obstruction.
Investigations
01Immediate right-arm and leg pulse and pressure assessmentFirst step
Why
Identify proximal-distal perfusion separation and grade emergency physiology.
Interpretation and limitations
Weak femoral pulses are important even without a measured gradient; shock can lower every pressure and hide separation.
02Blood gas, lactate, glucose and organ function
Why
Measure systemic-flow failure and reversible metabolic contributors.
Interpretation and limitations
Acidosis, rising lactate, oliguria and renal or hepatic injury indicate critical low output and guide response to ductal reopening.
03Urgent paediatric echocardiography
Why
Define arch continuity and narrowing, ductal flow, ventricular function and associated lesions.
Interpretation and limitations
This confirms neonatal anatomy and directs prostaglandin and surgery; a low Doppler gradient in poor output does not mean mild disease.
04Twelve-lead ECG and chest radiograph
Why
Assess ventricular pressure load, cardiomegaly and pulmonary congestion.
Interpretation and limitations
These describe consequences and alternatives but cannot exclude coarctation when pulses or hypertension remain suspicious.
05
Differential diagnosis
01
Neonatal sepsis
Poor feeding, shock and acidosis overlap; temperature instability and infection markers support sepsis, but normal femoral pulses and echo define the circulation.
02
Hypoplastic left heart
More extensive left-sided underdevelopment produces duct-dependent systemic flow with characteristic ventricular and valve anatomy on echocardiography.
03
Interrupted aortic arch
Complete discontinuity causes profound duct dependence and is distinguished anatomically from a narrowed but continuous arch.
04
Renal hypertension
Renal parenchymal or renovascular disease can produce childhood hypertension without radiofemoral delay or focal arch narrowing.
05
Cuff and pulse error
Incorrect cuff size, distress or comparing non-simultaneous pulses can create false gradients; repeat carefully without dismissing a convincing phenotype.
Management
01Neonatal emergencyRestore systemic flowFirst stepA newborn has weak femoral pulses, acidosis, oliguria or shock suggesting critical coarctation.+
1Begin ABCDE support, obtain two vascular access points, monitor continuously and treat sepsis or hypoglycaemia when indicated.
2Discuss immediately with paediatric cardiology and start alprostadil through a dedicated line according to the regional presentation-based dose.
3Track palpable pulses, lactate and acidosis, prepare for apnoea and transfer urgently for surgical repair.
02Stable childConfirm anatomy and hypertensionRadiofemoral delay, upper-limb hypertension or a suggestive murmur is found without shock.+
1Repeat right-arm and leg measurements with appropriate cuffs and obtain paediatric echocardiography.
2Use MRI or CT when arch extent, collaterals or intervention planning requires cross-sectional definition.
Complications
01
Neonatal multiorgan shock
Critical obstruction reduces renal, mesenteric and lower-body flow, causing acidosis, oliguria, hepatic injury and ventricular failure.
02
Systemic hypertension
Proximal pressure and persistent vascular dysfunction increase lifelong risks of ventricular hypertrophy, stroke and premature cardiovascular disease.
03
Recoarctation
Growth, scar contraction or residual arch hypoplasia can recreate clinically important obstruction after surgery or catheter treatment.
04
Aortic aneurysm or dissection
Abnormal wall tissue and repair sites can dilate or form aneurysm, requiring surveillance and sometimes reintervention.
05
Associated valve disease
A bicuspid aortic valve can develop stenosis, regurgitation or ascending-aortic enlargement independently of the repaired coarctation.
Monitoring and follow-up
During stabilisation, trend femoral pulses, right-arm pressure, capillary refill, urine output, blood gas and lactate and document the response to alprostadil.
Continuously monitor respiration, heart rate and blood pressure during prostaglandin infusion and ensure the transfer team can ventilate immediately.
After repair, measure right-arm blood pressure and femoral pulses at every review and compare with previous values rather than relying on symptoms.
Use ambulatory blood-pressure monitoring to detect masked hypertension and assess exercise pressure when specialist review indicates.
Perform periodic echocardiography and cross-sectional aortic imaging for recoarctation, aneurysm, bicuspid-valve disease and ventricular hypertrophy.
Continue lifelong congenital follow-up and transition, including advice on exercise, vascular risk, pregnancy and endocarditis prevention.
Special situations
Oximetry can be normal
Coarctation primarily obstructs systemic flow, so a baby may pass hypoxaemia screening before ductal constriction causes shock.
Low gradient can be critical
A failing ventricle cannot generate a large Doppler or cuff gradient, making poor perfusion and anatomy more important during collapse.
Use the right arm
Pressure in the left arm can be altered when the subclavian artery arises near the narrowing or has been used in repair.
Collateral flow hides obstruction
Enlarged intercostal vessels maintain resting leg perfusion and reduce the apparent gradient while hypertension and aortic risk persist.
Repair is lifelong disease
Even excellent childhood anatomy does not remove arterial stiffness, hypertension, bicuspid-valve or repair-site aneurysm risk.
Common pitfalls
01
Do not omit femoral pulse palpation in a septic-looking or tachypnoeic newborn.
02
Do not exclude coarctation after a normal newborn saturation screen.
03
Do not use a low gradient in shock to call the obstruction mild.
04
Do not delay prostaglandin in a strongly suspected duct-dependent collapse while awaiting formal echocardiography.
05
Do not run alprostadil through an unmonitored or unreliable line without an airway plan.
06
Do not compare pressures obtained with incorrect cuffs or from the left arm alone.
07
Do not stop surveillance after anatomically successful repair.
08
Do not treat post-repair hypertension without reassessing the repair site and whole aorta.
Surgery is usual in babies and young children. Balloon angioplasty or stenting is used selectively, especially in larger children, adolescents or recurrent narrowing.
Repair does not cure the arteriopathy: hypertension, recoarctation, aneurysm, bicuspid-valve disease and ascending-aortic dilatation can emerge later.
Lifelong congenital follow-up includes right-arm clinic and often ambulatory blood pressure, pulse and gradient assessment and periodic cross-sectional aortic imaging.
Metabolic acidosis, rising lactate, renal or liver injury and left-ventricular dysfunction are signs of inadequate systemic output and require emergency transfer.
Normal pulse oximetry does not exclude coarctation because obstruction may impair systemic flow without producing a large right-to-left saturation difference.
Severe headache, neurological symptoms, chest or back pain, marked hypertension or collapse in an older child raises hypertensive emergency or aortic complication.
Persistent or recurrent hypertension, radiofemoral delay or exercise leg pain after repair suggests recoarctation or abnormal vascular function and needs specialist reassessment.
Cardiac MRI or CT angiography
Why
Map the entire arch, repair site, collaterals, aneurysm and branch vessels in an older stable child.
Interpretation and limitations
Cross-sectional imaging complements echocardiography and informs catheter or surgical planning and lifelong surveillance.
06Ambulatory and exercise blood pressure
Why
Detect masked, sustained or exertional hypertension after repair.
Interpretation and limitations
An abnormal pattern may require treatment and closer aortic review even when the clinic gradient appears acceptable.
3
Refer through congenital cardiology for surgery, balloon treatment or stent according to age, size and anatomy.
03After repairSurveil the whole aortaA child has undergone surgical or catheter treatment for coarctation.+
1Check right-arm blood pressure, femoral pulses, ventricular response and the repair gradient at every cardiac review.
2Use ambulatory blood pressure and periodic MRI or CT to detect masked hypertension, recoarctation and aneurysm.
3Treat hypertension and reintervene for significant recurrent anatomy through the congenital aortic team.
04Associated diseaseCoordinate genetic and valve careBicuspid aortic valve, Turner features, another defect or family aortopathy is present.+
1Define valve, ascending-aortic and intracardiac anatomy and refer for genomic assessment when indicated.
2Follow syndrome-specific growth, renal, endocrine and reproductive care alongside cardiovascular surveillance.
3Offer family counselling and fetal-cardiac assessment in future pregnancies according to genetics and local protocol.
Key medicines and prescribing safety1 treatment · regimens, roles and cautions+
Reopens or maintains the arterial duct to restore descending-aortic flow as an emergency bridge to anatomical repair in critical neonatal obstruction.
Alprostadil infusion for suspected duct-dependent coarctation
Yorkshire neonatal protocol: if femoral pulses are poorly palpable but the infant is otherwise well and non-acidotic, start 25 nanograms/kg/min and double every 20 minutes to a maximum 100 nanograms/kg/min until pulses and lactate improve; an acidotic unwell infant starts 100 nanograms/kg/min with ventilation consideration.
Use a dedicated primed line with continuous neonatal monitoring and urgent cardiology or intensive-care involvement. Apnoea, hypotension and fever are important; high doses commonly require mechanical ventilation, and line delay or tissue infiltration can silently interrupt lifesaving delivery.