Coarctation of the Aorta

Congenital origin

• Coarctation of the aorta is most commonly a congenital malformation.
• It is increasingly recognised as part of a diffuse arteriopathy rather than an isolated defect.
• Frequently associated with malformations of the aortic valve, most notably a bicuspid valve, and with dilation of the ascending aorta.

Developmental theories

Haemodynamic theory

• Reduced blood flow across the aortic arch in fetal life impairs growth of the vessel wall, leading to narrowing. 
• This is especially relevant when coarctation coexists with other left-sided obstructive lesions such as hypoplastic left heart syndrome.

Ductal tissue theory

• Abnormal extension of ductal tissue into the aortic wall constricts the thoracic aorta once the ductus arteriosus closes postnatally.

Genetic factors

• Coarctation is thought to follow a multifactorial inheritance model, with both genetic and environmental influences.
• Familial clustering of coarctation and other left heart obstructive lesions (bicuspid aortic valve, aortic stenosis) suggests heritable mechanisms.

Syndromic associations

• Turner syndrome (45,X) is the strongest recognised genetic association, with coarctation affecting 15–20% of patients.
• Other chromosomal abnormalities and single-gene variants may contribute to congenital cardiovascular malformations, though less consistently.

Environmental and epidemiological influences

• Seasonal variation has been described, with increased occurrence during September and November.
• The cause of this pattern remains unclear but points towards possible environmental triggers during fetal cardiovascular development.

Acquired causes

• Takayasu arteritis, a large-vessel vasculitis, can produce segmental narrowing of the thoracic or abdominal aorta.
• Severe atherosclerotic disease has occasionally been reported to cause obstructive aortic lesions mimicking congenital coarctation.

Haemodynamic consequences

• The fundamental effect of coarctation of the aorta (CoA) is the imposition of increased afterload on the left ventricle.
• Severe narrowing, particularly after ductal closure in neonates, results in acute pressure overload, low cardiac output, and shock. This presentation is termed critical coarctation.
• In these cases, left ventricular pressures rise abruptly, left atrial pressure increases, and a left-to-right shunt across the foramen ovale may occur. If shunting does not occur, pulmonary venous congestion develops with subsequent right ventricular dilatation.
• In less severe narrowing, afterload rises more gradually, and children often compensate through the development of extensive collateral circulation via intercostal and other arteries.

Vascular wall abnormalities

• Pathological studies demonstrate medial thickening and intimal hyperplasia at the coarctation site, forming a posterolateral ridge that encircles the aortic lumen.
• Structural abnormalities have been reported even in the ascending aorta of neonates with CoA, including reduced distensibility, increased stiffness, altered collagen-to-smooth muscle ratios, and cystic medial necrosis.
• These intrinsic defects predispose to later complications such as aneurysm, dissection, or rupture either at the site of narrowing or following repair.

Mechanisms of hypertension

• The development of systemic hypertension in CoA is multifactorial and persists even after relief of the obstruction.
• The mechanical obstruction theory proposes that higher proximal pressures are required to maintain flow across the narrowed segment and collaterals. However, this does not fully explain the observed rise in systemic vascular resistance or the persistence of hypertension after repair.
• The humoral theory implicates activation of the renin–angiotensin–aldosterone system due to reduced renal perfusion distal to the obstruction. This model explains vasoconstriction, sodium retention, and vascular remodelling associated with chronic hypertension, though early studies found inconsistent renin elevation. More recent work demonstrates abnormalities in neurohumoral regulation, including RAAS activation and heightened sympathetic nervous system activity.
• Additional neurohormones such as vasopressin, endothelin, and brain natriuretic peptide (BNP) may also contribute, although their exact role in CoA-associated hypertension is less clearly defined.

Cardiac remodelling

• The increased left ventricular wall stress leads to concentric hypertrophy as a compensatory mechanism.
• Over time, this predisposes to diastolic dysfunction and, if untreated, to heart failure.
• Coexisting anomalies such as ventricular septal defect, aortic stenosis, or subaortic stenosis can exacerbate the haemodynamic burden.

Systemic effects

• Chronic elevation of upper body pressures contributes to vascular injury, accelerated coronary artery disease, and increased risk of intracranial aneurysms.
• Lower body hypoperfusion may impair renal function and growth in severe cases.
• The presence of extensive collaterals explains rib notching seen radiographically and may mask severity in some older patients.

Acquired or secondary coarctation

• Although the vast majority of cases are congenital, coarctation can result from other processes:
  • Inflammatory causes, particularly Takayasu arteritis, leading to narrowing of the thoracic or abdominal aorta.
  • Severe atherosclerosis, rarely producing obstructive lesions mimicking congenital CoA.
  • Trauma, especially blunt thoracic injury causing dissection and compromise of the true lumen, can present as an acute coarctation-like syndrome with lower extremity hypoperfusion.

Prevalence

• Coarctation of the aorta (CoA) accounts for approximately 4–8% of all congenital heart defects, with an estimated prevalence of 3–4 per 10,000 live births.
• It is one of the more frequent congenital cardiovascular malformations, but detection rates vary by region and age at presentation.

Sex distribution

• CoA occurs more commonly in males, with a male-to-female ratio of about 2:1.
• An exception is abdominal coarctation, a very rare form, which disproportionately affects females.
• The male predominance is most evident in older children and adults, whereas this sex difference is less marked in infants diagnosed early.

Geographic and racial variation

• International data suggest a lower prevalence (<2%) in Asian countries compared with European and North American populations.
• No consistent race-related differences have been confirmed, though some reports propose that the defect is less common in Asian cohorts.

Age distribution

• Presentation varies widely. Many infants with severe narrowing are diagnosed in the neonatal period due to heart failure after ductal closure.
• Despite this, studies indicate that CoA is often missed during the first year of life. In one large multicentre registry, the median age at referral to a paediatric cardiologist was 5 years.
• Among over 2,000 patients reported to the Pediatric Cardiac Care Consortium between 1985 and 1993, most were infants (1,337 cases), with fewer children (824) and rare adult presentations (31).

Familial risk and genetics

• Although most cases are sporadic, familial clustering has been described. CoA can occur as part of non-syndromic left ventricular outflow tract obstructive lesions, which show heritable patterns.
• First-degree relatives of affected patients may have an increased risk of congenital heart disease, emphasising the role of both genetic and environmental factors.

Associated anomalies and syndromes

• CoA is rarely an isolated lesion and is often associated with other cardiac malformations, particularly bicuspid aortic valve and ventricular septal defect.
• It may also occur as part of complex congenital syndromes such as Turner syndrome, Shone’s complex, DiGeorge syndrome, and hypoplastic left heart syndrome.
• These associations support the concept that CoA reflects a more generalised arteriopathy rather than a localised defect alone.

Neonates

• Critical coarctation often presents when the ductus arteriosus closes. Infants may suddenly deteriorate with poor feeding, tachypnoea, lethargy, irritability, diaphoresis, or overt shock.
• Parents may report the baby appearing well after birth and then becoming acutely unwell in the first few days or weeks of life.
• A history of pallor, poor perfusion, or sweating with feeds may be given.
• Differential cyanosis can be observed, with relatively higher oxygen saturation in the right arm compared to the lower limbs due to right-to-left shunting across a patent ductus.
• Family history should be explored, particularly in cases of syndromic associations such as Turner syndrome, where other stigmata may also be present.
• Neonatal sepsis is an important differential diagnosis in this age group and should be considered when obtaining history.

Older Infants and Children

• Presentation is often delayed, as symptoms may be subtle. Parents may report:
  • Poor weight gain or failure to thrive.
  • Cold extremities or fatigue on exertion.
  • Chest pain or discomfort.
  • Recurrent respiratory symptoms or exercise intolerance.
• In some children, the history may only reveal hypertension noted during evaluation for another condition.
• Symptoms of claudication, such as leg pain or weakness on exertion, may be elicited but are less common.
• A history of associated cardiac anomalies (e.g., ventricular septal defect, patent ductus arteriosus, or bicuspid aortic valve) should be sought, as these influence presentation.

Adolescents and Adults

• In undiagnosed individuals, the most common historical clue is hypertension, often longstanding or resistant to therapy.
• Symptoms reported may include:
  • Headaches, sometimes severe and occasionally related to intracranial haemorrhage due to associated cerebral aneurysms.
  • Epistaxis.
  • Chest pain, palpitations, or features of heart failure if longstanding hypertension has led to cardiac compromise.
  • Fatigue or leg claudication with exercise due to reduced perfusion of the lower extremities.
• Many adults remain asymptomatic, and the diagnosis may only be suspected after incidental discovery of hypertension or cardiovascular complications.

Natural History

• Historical accounts from the pre-surgical era showed an average survival of around 35 years in unoperated patients, with 75% mortality by mid-40s.
• Death was commonly attributed to complications such as heart failure, aortic rupture or dissection, stroke, coronary artery disease, endocarditis, or intracranial haemorrhage.
• Patients with a bicuspid aortic valve may develop additional complications including aortic stenosis, aortic regurgitation, or ascending aortic aneurysm, which should be considered when taking a detailed history.

Early Presentation (Neonates)

• Infants may present in extremis with tachypnoea, tachycardia, increased work of breathing, or overt shock.
• All pulses may be diminished in severe heart failure, but once stabilised, prominent brachial pulses with weak or absent femoral pulses become more apparent.
• Key diagnostic findings include discrepancies in blood pressure (BP) between the upper and lower extremities and a characteristic brachial–femoral pulse delay.
• In cases with ductal dependency, BP gradients may not be obvious despite significant obstruction.
• Differential cyanosis (well-oxygenated upper body and cyanotic lower body) can be detected, often confirmed by preductal and postductal pulse oximetry.
• Murmurs may be systolic and best heard in the left infraclavicular region or beneath the left scapula, though they can be nonspecific. A gallop rhythm suggests ventricular dysfunction, and an ejection click indicates a bicuspid aortic valve.

Later Presentation (Older Infants and Children)

• Hypertension or a cardiac murmur may prompt further investigation.
• Simultaneous palpation of brachial and femoral pulses highlights the brachial–femoral delay, with diminished or absent femoral pulses.
• A BP difference greater than 20 mmHg between upper and lower extremities is strongly suggestive of coarctation.
• Involvement of the left subclavian artery may cause lower BP in the left arm compared to the right. Anomalous origin of the right subclavian artery distal to the obstruction may produce decreased right brachial pulses.
• Murmurs may be systolic or continuous due to flow across the narrowed area or through collateral vessels. Additional murmurs can result from associated defects such as PDA, VSD, or aortic stenosis.

Adolescents and Adults

• Classic examination findings include hypertension in the arms with diminished or delayed femoral pulses and lower leg BP.
• Collateral circulation may reduce pulse discrepancies, but prominent intercostal pulsations may be palpable.
• A systolic murmur over the left scapula or a continuous murmur from collaterals is common.
• Suprasternal or precordial thrills may suggest associated valve lesions. Retinal vascular changes and suprasternal pulsations may also be observed.
• Abdominal bruits are rarely present in cases of abdominal coarctation.

Cardiac Examination Findings

• First and second heart sounds are typically normal unless pulmonary hypertension is present.
• An ejection systolic click suggests a bicuspid aortic valve.
• A systolic murmur extending beyond the second heart sound is often heard in the interscapular region.
• Continuous murmurs indicate flow through large collaterals.

Non-Cardiac Findings

• In female patients, clinical features of Turner syndrome (e.g., webbed neck, shield chest, short stature, lymphoedema) should be sought.
• Patients with DiGeorge syndrome, hypoplastic left heart syndrome, Shone’s complex, or PHACE syndrome may also show coarctation in association with other anomalies.
• In adults, coarctation is linked with an increased risk of intracranial aneurysms, detected in ~10% by imaging. This risk is higher in older hypertensive patients.
• Dilated spinal collateral vessels may rarely rupture, leading to spinal subarachnoid haemorrhage.

Electrocardiogram (ECG)

• In neonates with severe coarctation, right ventricular hypertrophy (RVH) may be present due to elevated right-sided pressures.
• Older children and adults more commonly show left ventricular hypertrophy (LVH) from chronic pressure overload.
• ECG may be normal in some cases, but this should not exclude further testing if examination suggests coarctation.

Chest Radiography (CXR)

• In infants with critical coarctation, findings may include cardiomegaly and pulmonary venous congestion.
• Older patients may demonstrate the classic “3 sign” at the site of narrowing, or posterior rib notching due to collateral circulation.
• Rib notching is typically seen after the age of 5 years.
• Although useful, CXR is not required before echocardiographic confirmation.

Echocardiography

• Transthoracic echocardiography (TTE) is the first-line imaging modality and establishes the diagnosis in most patients.
• Suprasternal and high parasternal views visualise the aortic arch, revealing discrete narrowing in the juxtaductal region.
• Colour and spectral Doppler can estimate the pressure gradient across the coarctation and demonstrate turbulence or diastolic runoff.
• In neonates, echocardiography can also assess ductal patency and identify associated anomalies such as bicuspid aortic valve, VSD, or aortic arch hypoplasia.
• Abdominal aortic Doppler often shows delayed systolic upstroke and persistent diastolic flow in significant obstruction.

Computed Tomography Angiography (CTA)

• Provides detailed three-dimensional reconstruction of the aortic arch and collaterals.
• Particularly useful in adolescents and adults to define anatomy pre-intervention.
• Recommended to screen older patients with coarctation for associated intracranial aneurysms.

Magnetic Resonance Imaging (MRI) / Magnetic Resonance Angiography (MRA)

• Offers excellent anatomical definition without ionising radiation, preferred for long-term follow-up.
• Useful to delineate the arch and collateral circulation, and to monitor for aneurysm formation or recoarctation post-repair.
• MRA can also screen for intracranial aneurysms, especially in hypertensive adults.
• Anaesthesia may be required in young children.

Cardiac Catheterisation

• Now largely reserved for interventional purposes (balloon angioplasty or stenting).
• Provides direct pressure gradient measurements across the narrowed segment.
• Indicated in complex cases where non-invasive imaging is inconclusive, or when coronary artery disease is suspected in adults.
• A peak-to-peak gradient >20 mmHg generally indicates significant obstruction, though collateral flow may reduce the measured gradient.

Laboratory Studies

• In neonates presenting in shock: blood, urine, and CSF cultures to exclude sepsis; electrolytes, renal function, glucose, lactate, and arterial blood gases to assess metabolic status.
• In older children and adults with hypertension: urinalysis, renal function, glucose, and electrolytes to evaluate secondary complications.
• Preductal and postductal oximetry can help confirm right-to-left ductal shunting in neonates.

Prenatal Diagnosis

• Antenatal ultrasound is challenging; only a minority of cases are detected before birth.
• Suspicion may arise with findings such as a small left ventricle or disproportion between the aortic and ductal arches.
• Serial echocardiography improves detection rates.

Neonatal Shock

• CoA may mimic other critical neonatal conditions that present with shock after ductal closure.
• Important considerations include:
  • Hypoplastic left heart syndrome – Underdeveloped left-sided cardiac structures with severe systemic outflow obstruction.
  • Critical aortic stenosis – Severe narrowing of the aortic valve causing low cardiac output.
  • Endocardial fibroelastosis – Diffuse thickening of the endocardium leading to impaired ventricular function.
  • Dilated cardiomyopathy – Impaired myocardial contractility resulting in heart failure and shock.
  • Neonatal sepsis – Can present with shock and should always be excluded with appropriate cultures.
  • Perinatal asphyxia – A non-cardiac cause of shock due to hypoxic injury.
  • Adrenal insufficiency (Addison disease/CAH) – May cause cardiovascular collapse in neonates.
• Echocardiography differentiates CoA from these conditions.

Unequal Pulses and Blood Pressures

• Aortic dissection – Rare in children but possible following trauma or connective tissue disorders. Presents with pulse discrepancies and acute pain.
• Obstructive peripheral arterial disease – Thrombosis or iatrogenic arterial injury (e.g., after catheterisation).
• Interrupted aortic arch – Similar to critical coarctation in neonates but echocardiography confirms complete interruption.
• Prior surgical ligation – For example, previous Blalock-Thomas-Taussig shunt can mimic pulse asymmetry.

Hypertension in Children and Adults

• Essential hypertension – Usually lacks differential limb blood pressure or pulse delay.
• Renal artery stenosis – Produces secondary hypertension; Doppler or angiography confirms diagnosis.
• Phaeochromocytoma – Catecholamine excess causing hypertension with palpitations, flushing, and headaches. Diagnosed by elevated urinary or plasma catecholamines/metanephrines.

Other Left Ventricular Outflow Tract (LVOT) Obstructions

• Valvar, subvalvar, or supravalvar aortic stenosis – Produce murmurs and pressure gradients distinguishable on echocardiography.
• Shone’s complex – Multi-level left-sided obstruction (supravalvar mitral ring, parachute mitral valve, subaortic stenosis, and CoA).

Myocardial and Inflammatory Conditions

• Viral myocarditis – May mimic heart failure and shock in infants or children.
• Endocarditis/endarteritis – Rare causes of systemic compromise but should be considered in complex congenital heart disease.

Other Considerations

• Trauma with aortic dissection – Blunt chest injury may result in traumatic coarctation or aortic malperfusion.
• Shock syndromes – Non-cardiac causes (e.g., septic shock, hypovolaemic shock) must be excluded in acutely unwell infants.

General Indications for Intervention

• Resting peak-to-peak gradient >20 mmHg (by Doppler or catheterisation).
• Radiological evidence of significant collateral circulation.
• Systemic hypertension attributable to CoA.
• Congestive heart failure attributable to obstruction.
• Critical CoA in neonates with duct-dependent systemic flow.

Critical Coarctation in Neonates

• Intravenous prostaglandin E1 (alprostadil) is administered to maintain ductal patency.
• Inotropic agents (milrinone, dopamine, dobutamine) are used for ventricular dysfunction.
• Supportive care corrects metabolic acidosis, hypoglycaemia, respiratory compromise, and anaemia.
• Once stabilised, neonates usually undergo surgical repair, which is preferred over balloon angioplasty due to lower reintervention rates.
• Emergency balloon angioplasty is reserved as palliation in unstable infants.

Surgical Repair

• Short segment narrowing: resection with extended end-to-end anastomosis.
• Medium segment narrowing: subclavian flap aortoplasty or patch augmentation.
• Long segment narrowing: bypass graft across the narrowed arch.
• Mortality is rare in experienced centres, with recoarctation in ~6–10%.
• Complications include postoperative hypertension, recurrent laryngeal/phrenic nerve injury, chylothorax, paradoxical hypertension, subclavian steal, and rarely spinal cord ischaemia.

Percutaneous Repair

Balloon angioplasty

• Used in children >4 months with discrete CoA (<25 kg).
• Provides immediate gradient relief but carries higher restenosis and aneurysm risks.
• Not recommended in neonates or infants <4 months, particularly with arch hypoplasia.

Stent implantation

• Preferred in older children and adults (≥25 kg).
• Bare-metal stents are effective; covered stents may reduce aneurysm risk.
• Complications occur in ~12–14% (access injury, dissection, aneurysm).
• Long-term reinterventions are required in children as stents need redilation during growth.
• Antiplatelet therapy (e.g., aspirin) is recommended for 6 months post-stent placement.

Recurrent Coarctation

• Occurs in 10–20% of patients after initial repair.
• Balloon angioplasty is first-line for isolated restenosis.
• Stent placement is used in older children and adults.
• Repeat surgery is reserved for complex or refractory cases.

Pregnancy Considerations

Preconception

• Women with CoA (repaired or unrepaired) require evaluation by congenital heart disease specialists.
• Risks include maternal hypertension, pre-eclampsia, dissection/rupture, and CHD in offspring.
• Turner syndrome patients need careful assessment before conception.

During pregnancy

• Repaired CoA: most tolerate pregnancy well, though miscarriage and hypertensive disorders are more common.
• Unrepaired or residual CoA increases risks of dissection, rupture, and poor foetal outcomes.
• Medical management is preferred; covered stents may be used if refractory hypertension or maternal/foetal compromise occurs.

Mode of delivery

• Vaginal delivery with epidural anaesthesia is generally preferred.
• Caesarean section is reserved for obstetric indications or severe cardiac compromise.

Complications in offspring

• Preterm delivery rate (~8%) is similar to the general population.
• CHD in offspring occurs in ~4%, higher than baseline population risk.
• Perinatal mortality (2–3%) is higher than in the general population (<0.5%).

Long-Term Outcomes and Follow-Up

• Lifelong surveillance is required for recoarctation, aneurysms, hypertension, and cardiovascular disease.
• CMR or CTA is used for periodic imaging.
• Antihypertensive therapy is often necessary (beta-blockers or ACE inhibitors).

General Outlook

• Patients with isolated, successfully repaired CoA generally have excellent outcomes.
• Even after anatomically successful repair, many patients require long-term antihypertensive therapy (ACE inhibitors, beta blockers, angiotensin receptor blockers).
• Prognosis is influenced by associated cardiac malformations, age at repair, degree/duration of preoperative hypertension, and development of long-term sequelae.

Mortality and Survival Data

• Historically, untreated CoA carried a 90% mortality by age 50, with mean survival of 35 years.
• Surgical correction markedly improves life expectancy, though survival remains lower than in the healthy population.
• Deaths are often related to recoarctation, aneurysm rupture, endocarditis, uncontrolled hypertension, or heart failure.
• Studies indicate that pulmonary hypertension related to restrictive left ventricular physiology is a major predictor of cardiovascular death and heart failure after childhood repair.

Hypertension

• Hypertension is the most common long-term complication and may persist despite adequate repair.
• Risk is linked to the severity and duration of preoperative hypertension, alterations in baroreceptor sensitivity, and renin–angiotensin system activation.
• Persistent hypertension contributes to premature atherosclerosis, ventricular dysfunction, cerebral aneurysm rupture, and coronary artery disease.

Recoarctation

• Recurrence occurs in 10–20% of patients and is associated with younger age at repair, small patient size, arch hypoplasia, and type of repair.
• Recoarctation may not appear until years after initial surgery, often during adolescence with rapid growth.
• Both surgical scarring and abnormal growth of the arch/isthmus contribute to recurrence risk.

Aortic Aneurysm

• Aneurysms can arise in untreated CoA or at the repair site.
• Risks are higher after patch aortoplasty, particularly when excision of the coarcted tissue shelf is performed.
• Mycotic aneurysms secondary to endocarditis, and aneurysms in Turner syndrome, have been described.
• MRI or CT angiography is preferred for surveillance; chest radiography is often insensitive.

Cerebral Aneurysms

• Intracranial aneurysms occur in up to 10% of patients with CoA, often multiple and increasing with age.
• Hypertension accelerates aneurysm growth and rupture risk.
• Many are asymptomatic until rupture; sentinel symptoms such as severe headache or photophobia may occur.
• Rupture is frequently fatal; repair of both the cerebral aneurysm and the CoA is indicated.

Cardiac Complications

• Patients are predisposed to coronary artery disease, heart failure with preserved ejection fraction, and sudden death.
• Dilated and hypertrophic cardiomyopathy may occur, particularly in infants with critical CoA and additional left heart obstructive lesions.
• Endocardial fibroelastosis is a recognised cause of chronic dilated cardiomyopathy in this setting.
• Valvar aortic stenosis, subaortic stenosis, or mitral valve disease may develop over time, requiring later intervention.

Neurological Complications

• Rarely, spinal cord ischaemia can cause paraplegia.
• Risk factors include poor collateral circulation, prolonged cross-clamp time, or extensive sacrifice of intercostal arteries during repair.
• Preventive measures include hypothermia, partial bypass shunting, and careful preservation of collateral flow.

Other Complications

Chylothorax

• May occur postoperatively from thoracic duct injury.
• Management includes dietary modification, drainage, and in refractory cases pleurodesis or surgical ligation.

Postcoarctectomy Syndrome

• Caused by sudden restoration of pulsatile flow to mesenteric vessels leading to arteritis, vasoconstriction, and possible bowel necrosis.
• Symptoms range from mild abdominal pain to acute abdomen with haemorrhage.
• Risk is reduced by delayed feeding, nasogastric decompression, and careful postoperative blood pressure control.

Long-Term Considerations

• Lifelong cardiology follow-up is required, with surveillance for recoarctation, aneurysms, and hypertension.
• CMR or CT angiography is recommended at intervals to assess arch anatomy and detect complications.
• Endocarditis prophylaxis is often recommended, though guidelines differ.
• Patients without residual obstruction and well-controlled blood pressure can live normal, unrestricted lives.

Recoarctation

• Recoarctation refers to recurrent narrowing after initially successful surgical or catheter-based repair.
• Clinical features may include resting hypertension, headaches, or claudication, though it is often detected incidentally on surveillance imaging.
• After surgery, the risk is 5–15%, most common in children operated on before the aorta has reached adult size. Rates appear similar across surgical techniques.
• After balloon angioplasty, recurrence varies with age: up to 50% in neonates and infants, 20–30% in older children, and around 8% in adolescents and adults.
• Risk factors include isthmus hypoplasia and small vessel calibre before or after repair.
• Most cases can be managed with repeat balloon angioplasty or stent placement.

Systemic Hypertension

• Persistent or recurrent hypertension is one of the most common long-term sequelae, occurring even without significant residual narrowing.
• Mechanisms include altered baroreceptor sensitivity and activation of the renin–angiotensin system.
• Hypertension predisposes to accelerated atherosclerosis, ventricular dysfunction, cerebral aneurysm rupture, and coronary artery disease.
• A pressure gradient >20 mmHg between upper and lower extremities (particularly on exercise) is considered significant and may prompt re-intervention.

Aortic Aneurysm

• Aneurysm formation may occur at the site of repair, following balloon angioplasty, or in association with bicuspid aortic valve or underlying arteriopathy.
• Patch aortoplasty carries an especially high risk of aneurysm formation.
• Aneurysms may be asymptomatic or present with hoarseness due to recurrent laryngeal nerve stretching.
• MRI and CT angiography are preferred for surveillance.
• Treatment includes surgical resection or covered stent placement.

Coronary Artery Disease

• Patients with delayed repair of CoA are at increased risk of premature coronary artery disease.
• This is strongly linked to chronic systemic hypertension and vascular dysfunction.
• Coronary artery disease remains a leading cause of late mortality in this population.

Cerebral Aneurysms

• Berry aneurysms of the circle of Willis occur in up to 10% of patients with CoA.
• They may enlarge with age and are more likely to rupture in the presence of uncontrolled hypertension.
• Many are silent until rupture, but prodromal symptoms such as sudden headache or photophobia may precede haemorrhage.
• Rupture carries high mortality and warrants both aneurysm and coarctation treatment.

Psychological and Neurodevelopmental Issues

• Depression and anxiety are common, affecting up to half of patients with congenital heart disease.
• Early-life intensive care experiences and repeated interventions contribute to psychological stress.
• Routine integration of psychological care, with access to psychotherapy and pharmacotherapy, is recommended.

Other Complications

Cardiomyopathy

• Infants with critical CoA may develop dilated or hypertrophic cardiomyopathy, sometimes requiring transplantation.

Spinal Cord Ischaemia

• Rare, but can lead to paraplegia, particularly if collateral vessels are poorly developed or cross-clamp times are prolonged.

Chylothorax

• May follow thoracic duct injury during surgery, requiring dietary modification, drainage, or occasionally pleurodesis.

Postcoarctectomy Syndrome

• Due to sudden mesenteric hyperperfusion, leading to abdominal pain, ileus, haemorrhage, or perforation. Prevention includes delayed feeding and careful BP control.

Progressive Valve Disease

• Valvar aortic stenosis, subaortic stenosis, and mitral valve stenosis may develop over time, sometimes necessitating intervention.

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