Coarctation of the aorta

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Most coarctation lies near the ductal insertion. Adults may present with resistant hypertension, headache, exertional leg fatigue or an incidental arm-leg pressure difference; previously repaired patients may develop recoarctation or aneurysm.

Assessment belongs in an ACHD/aortic service. The team integrates blood pressure, collateral flow, anatomy, ventricular response and associated valve/aortic disease when choosing stent, surgery or surveillance.

Key points

Measure blood pressure in both arms and at least one leg; upper-limb hypertension with a lower leg pressure and radiofemoral delay is the bedside clue.
A systolic murmur over the left infraclavicular area or back and collateral bruits may be present.
Coarctation is an aortopathy, not simply a focal narrowing; inspect the arch, repair site and entire thoracic aorta.
Bicuspid aortic valve and ascending-aortic dilatation are common associated lesions.
CMR is preferred for serial anatomy and flow; CT is valuable for stents, calcification and emergency detail.
Intervention is generally indicated for significant obstruction with upper-limb hypertension, particularly when an invasive peak-to-peak gradient is at least 20 mmHg.
Hypertension and aortic complications can persist after an anatomically successful repair, so follow-up is lifelong.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Congenital juxtaductal narrowing

Abnormal development of the aortic arch and tissue near the ductal insertion produces a fixed narrowing, usually just beyond the left subclavian artery. Severity varies considerably.

Associated congenital aortopathy

Bicuspid aortic valve, ascending-aortic dilatation and ventricular septal defect occur more often in affected people. These associated lesions influence presentation, surveillance and complication risk.

Residual or recurrent obstruction

After childhood surgery or catheter treatment, residual narrowing, scar-related restenosis or altered growth may recreate obstruction. Repair sites can also develop aneurysmal change.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Fixed outflow obstruction
The narrowed aortic segment increases resistance between the upper and lower body. Pressure rises proximally while distal pulse amplitude and perfusion pressure fall.
2
Ventricular and vascular adaptation
The left ventricle hypertrophies in response to increased afterload. Neurohormonal and vascular dysfunction can sustain upper-body hypertension even when the anatomical obstruction is later relieved.
3
Collateral circulation develops
Intercostal and other arterial collaterals enlarge to bypass the narrowing. They may produce posterior bruits or rib notching and can mask the resting arm–leg pressure difference.
4
Aortic wall stress persists
Abnormal flow, hypertension and associated aortopathy expose the ascending aorta and repair site to continuing stress. Dilatation, aneurysm or dissection may occur despite previous intervention.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Arm-leg discrepancy

Raised arm systolic pressure with lower leg pressure, weak/delayed femoral pulses and radiofemoral delay.

Collateral circulation

Intercostal collateral bruits, scapular pulsation or rib notching on chest radiograph may accompany longstanding obstruction.

Adult symptoms

Headache, epistaxis, exertional leg fatigue, cold feet, chest pain or dyspnoea; many people are asymptomatic despite hypertension.

Associated disease

Bicuspid aortic valve, ascending-aortic dilatation, VSD and intracranial aneurysm risk should be considered.

Aortic emergencyRed flag

Sudden tearing chest/back pain, neurological signs or shock suggests dissection or rupture.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Four-limb blood pressure and pulse examinationFirst step
Why
Screen for haemodynamic obstruction and hypertension.
Interpretation and limitations
A resting systolic arm-leg difference of 20 mmHg or more supports significant coarctation, but collateral flow can mask the gradient.
02
Transthoracic echocardiography
Why
Assess Doppler flow, LV hypertrophy/function, bicuspid valve and proximal aorta.
Interpretation and limitations
Doppler gradients may overestimate or underestimate catheter gradients; look for diastolic run-off and whole physiology.
03
CMR angiography
Why
Define arch, narrowing, collateral flow, repair site and aortic dimensions without radiation.
Interpretation and limitations
Use serial measurements with the same technique when possible.
04
CT angiography
Why
Provide high-resolution aortic and stent anatomy, especially in emergencies or when CMR is unsuitable.
Interpretation and limitations
Balance diagnostic value against radiation and contrast exposure.
05
Ambulatory BP and exercise testing
Why
Detect masked or exercise-induced hypertension and assess functional response.
Interpretation and limitations
Normal clinic pressure does not exclude a clinically important hypertensive burden after repair.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Essential hypertension

Primary hypertension is common but does not usually cause radiofemoral delay, a consistent arm–leg pressure difference or an interscapular murmur. Four-limb assessment helps separate the patterns.

Renovascular or endocrine hypertension

Renal artery disease and endocrine disorders can cause early or resistant hypertension without focal arch obstruction. Biochemical clues and renal imaging guide evaluation when limb findings are absent.

Lower-limb peripheral arterial disease

Aortoiliac or leg arterial disease may lower ankle pressure and weaken femoral pulses. Asymmetry, distal vascular signs and imaging below a normal aortic arch favour acquired peripheral disease.

Large-vessel arteritis

Inflammatory aortic disease can create stenoses, pulse differences and hypertension. Systemic inflammatory features, multifocal arterial involvement and vessel-wall imaging distinguish it from a congenital focal lesion.

Subclavian disease or measurement artefact

Proximal arm-artery stenosis or an inaccurate cuff reading can distort the apparent arm–leg gradient. Repeated four-limb measurements, pulse examination and arch imaging clarify the pattern.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01FirstSuspected native or recurrent coarctationFirst stepYoung or resistant hypertension, arm-leg BP difference, radiofemoral delay or previous repair.

1Measure both-arm and leg blood pressures, examine femoral pulses and listen over the precordium and back.
2Obtain ECG and expert echo for LV, valve and Doppler assessment.
3Refer to an ACHD/aortic service and obtain CMR or CT of the whole thoracic aorta.
4Use ambulatory BP and, when appropriate, exercise testing to define the true hypertensive burden.

02NextIntervention assessmentSignificant anatomical narrowing with hypertension, symptoms, LV effects or a meaningful invasive gradient.

1Confirm anatomy, collaterals and associated aortic/valve disease in the ACHD multidisciplinary team.
2Use catheter haemodynamics when needed; a peak-to-peak gradient of at least 20 mmHg supports intervention in a hypertensive patient.
3Prefer stenting in anatomically suitable adults; use surgery for anatomy not suited to catheter treatment or complex associated disease.
4Image the repair for residual obstruction, dissection or aneurysm and establish lifelong surveillance.

03EscalationSuspected aortic complicationEscalationAcute chest/back pain, collapse, new neurological deficit or rapidly changing aortic signs.

1Activate an emergency aortic-syndrome pathway with ABC management and senior cardiothoracic/aortic input.
2DefinitiveObtain immediate ECG, blood tests and definitive CT aortography unless instability requires direct operative action.
3DefinitiveControl heart rate and blood pressure under specialist emergency protocols while avoiding delay to definitive treatment.
4Transfer to an aortic centre for endovascular or surgical management as anatomy dictates.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Persistent systemic hypertension

Upper-body hypertension may continue after technically successful repair because vascular dysfunction persists. It increases risk of left-ventricular hypertrophy, heart failure, coronary disease and stroke.

Aortic aneurysm or dissection

Hypertension, intrinsic aortopathy and repair-site injury can weaken the aortic wall. Aneurysm, rupture or dissection may present with abrupt chest or back pain and collapse.

Recoarctation

Residual tissue, scarring or vessel growth can restore a clinically important obstruction. Recurrent arm–leg pressure disparity, hypertension or exercise intolerance should prompt anatomical reassessment.

Bicuspid aortic valve disease

Associated bicuspid valve may develop stenosis or regurgitation, while the ascending aorta can dilate. These processes add ventricular load independently of the coarctation gradient.

Cerebrovascular complication

Longstanding hypertension and associated intracranial aneurysm susceptibility increase risk of ischaemic or haemorrhagic neurological events. New severe headache or focal deficit warrants urgent assessment.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Lifelong ACHD follow-up with arm and leg blood pressure at every clinical review.
Use ambulatory BP periodically because masked hypertension is common after repair.
Perform serial CMR or CT of the arch, repair/stent and thoracic aorta at specialist-defined intervals.
Monitor bicuspid valve function, ascending-aortic size and LV hypertrophy/function by echo.
Provide pre-pregnancy aortic imaging and Pregnancy Heart Team review when residual obstruction, hypertension or aortic dilatation is present.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Check the right arm

A lesion involving the left subclavian origin can alter the left-arm pressure; both arms reduce misclassification.

Collateral flow masks gradients

Severe anatomical narrowing may coexist with a modest resting pressure difference when collaterals are extensive.

Repair is not cure

Vascular dysfunction sustains lifelong hypertension and premature vascular risk even after relief of obstruction.

Whole-aorta imaging

The repair site can develop aneurysm while the ascending aorta may dilate because of associated bicuspid-valve aortopathy.

Exercise BP adds information

An exaggerated response can reveal clinically relevant physiology not apparent at rest.

11Common pitfallsFrequent interpretation and management errors.

01
Measuring blood pressure in one arm only and never checking a leg.
02
Excluding significant coarctation because the resting Doppler or cuff gradient is below 20 mmHg.
03
Imaging only the focal narrowing instead of the entire thoracic aorta.
04
Stopping follow-up after childhood repair.
05
Allowing uncontrolled hypertension before pregnancy or high-static exercise without specialist assessment.