Coarctation of the Aorta: Causes, Symptoms, Diagnosis and Treatment — Overview, Diagnosis & Treatment Options | MyMedicPlus

Coarctation of the aorta (CoA) is a congenital narrowing of the aorta, occurring most commonly at the aortic isthmus — the short segment just distal to the origin of the left subclavian artery, adjacent to the ligamentum arteriosum (remnant of the ductus arteriosus). It accounts for 5-8% of all congenital heart defects, with an incidence of approximately 1 in 2,500 live births. CoA obstructs systemic blood flow, creating upper body (arms and head) hypertension and relatively reduced pressure and perfusion to the lower body (legs and abdominal organs). CoA presents across a clinical spectrum: severe neonatal presentations with cardiovascular collapse when the ductus arteriosus closes, milder childhood presentations with upper limb hypertension, or asymptomatic adult presentations discovered incidentally. Association with bicuspid aortic valve (BAV) occurs in approximately 50-85% of CoA patients, and with Turner syndrome (45,X) in approximately 10-15% of females with CoA. Despite successful repair, long-term complications including persistent hypertension, aortic aneurysm, and premature cardiovascular disease necessitate lifelong surveillance.

CoA is a congenital structural defect resulting from abnormal embryological development of the aortic arch. Two main theories of pathogenesis: (1) the ductal tissue theory — extension of smooth muscle from the ductus arteriosus into the aortic wall, which constricts with ductal closure after birth, producing narrowing; and (2) reduced flow hypothesis — diminished aortic arch blood flow in utero (due to left-sided cardiac obstructions) leads to underdevelopment. Genetic causes: Turner syndrome (45,X) is the strongest single-gene association — approximately 10-15% of female CoA patients have Turner syndrome; CoA is found in 30-35% of Turner syndrome individuals. NOTCH1, NKX2.5, GATA4, and ELN gene variants have been associated with CoA in sporadic cases. Bicuspid aortic valve (BAV), ventricular septal defect (VSD), patent ductus arteriosus (PDA), and hypoplastic left heart syndrome frequently co-occur with CoA. Male sex is slightly more common (approximately 2:1 male predominance). Familial clustering occurs in approximately 5% of cases, supporting a polygenic susceptibility.

Neonatal presentation (severe coarctation, duct-dependent circulation): cardiovascular collapse and cardiogenic shock within 24-72 hours of birth as the ductus arteriosus closes; absent or weak femoral pulses; metabolic acidosis; differential cyanosis (lower limbs more cyanotic than upper). Childhood and adolescent presentation: upper limb hypertension with headaches; diminished femoral pulses relative to radial pulses; radiofemoral delay on clinical examination; lower limb claudication with exercise; cold feet; epistaxis from hypertension. Adult presentation: frequently asymptomatic until complications occur; hypertension resistant to medications; auscultation reveals a harsh systolic ejection murmur over the left interscapular region; systolic hypertension differential between arm and leg BP exceeding 20 mmHg is the cardinal clinical sign. Chest X-ray classic findings: rib notching (3rd-8th ribs) from intercostal arterial collateral development; the '3 sign' (double aortic knuckle on frontal CXR) representing pre- and post-stenotic aortic dilation.

Clinical suspicion: blood pressure differential greater than 20 mmHg between right arm and legs, diminished femoral pulses, or incidental aortic narrowing on imaging. Echocardiography (transthoracic): determines anatomy, gradient across coarctation (Doppler), associated defects (BAV, VSD, patent foramen ovale), and ventricular function. CT aortography or MRI (cardiac MRI with contrast): definitive anatomical delineation for intervention planning in children over 2 years and adults; MRI avoids ionizing radiation (preferred in young patients). Cardiac catheterization: measures peak-to-peak gradient across the coarctation (significant if 20 mmHg or greater); definitive for planning and performing transcatheter intervention. AHA/ACC 2018 guidelines classify CoA as hemodynamically significant if peak-to-peak gradient is 20 mmHg or greater or collateral flow is angiographically demonstrated. ARM blood pressure and four-limb BP measurement is the simplest non-invasive screening tool. Genetic testing (karyotype for Turner syndrome) is indicated in all female patients with CoA.

Medical stabilization of neonatal coarctation: prostaglandin E1 (alprostadil) infusion to reopen and maintain patency of the ductus arteriosus while preparing for definitive repair — lifesaving in duct-dependent neonates presenting with cardiovascular collapse. Definitive repair: Surgical resection with extended end-to-end anastomosis is the preferred approach in neonates and infants under 15 kg. Subclavian flap aortoplasty and Dacron patch repair are historical approaches with higher rates of long-term aortic aneurysm formation and are no longer preferred. Balloon angioplasty with covered stent implantation (Cheatham-Platinum stent or AndraStent) is the preferred treatment for native discrete coarctation in children over 25 kg, adolescents, and adults; also the treatment of choice for recurrent coarctation after surgery — AHA/ACC Class I recommendation at experienced centers. Post-intervention hypertension management: most patients require antihypertensive therapy after repair; ACE inhibitors, ARBs, and beta-blockers are standard first-line agents. Endocarditis prophylaxis for 6 months post-intervention. Lifelong cardiology surveillance: annual BP measurement, 4-limb BP check, echocardiography, and MRI or CT aortography every 5 years per AHA/ACC 2018 guidelines.

Prognosis after coarctation repair has improved dramatically with modern surgical and catheter-based techniques. Neonatal surgical mortality for isolated CoA at specialized centers is less than 5%. Without treatment, median survival of severe CoA is approximately 35 years, with nearly 90% mortality by age 50 from hypertension-related complications including stroke, aortic dissection, heart failure, and premature coronary artery disease. After successful repair: 20-year survival exceeds 85-90%, but the risk of premature cardiovascular death remains 2-5 times higher than age-matched controls due to residual hypertension, aortic aneurysm at the repair site, and bicuspid aortic valve disease progression. Residual or recurrent hypertension occurs in 30-50% of patients repaired in adulthood and 15-25% of those repaired in childhood — directly linked to increased risk of aortic dissection, stroke, and coronary artery disease over a lifetime. Aortic aneurysm at the repair site occurs in 5-15% of patients repaired with patch techniques (subclavian flap or Dacron patch), with lower rates after extended end-to-end anastomosis or covered stent. Re-coarctation requiring intervention develops in approximately 5-10% over 20 years of follow-up. Key prognostic factors include age at repair (earlier repair, especially before age 2, yields better blood pressure outcomes and reduced late cardiovascular risk), severity of pre-repair CoA, type of repair, and adequacy of long-term blood pressure control. Bicuspid aortic valve, present in 50-85% of CoA patients, often progresses to require valve intervention in the fourth to sixth decade. AHA/ACC 2018 guidelines recommend lifelong surveillance: annual 4-limb blood pressure assessment, echocardiography every 3-5 years, and MRI or CT aortography every 5 years to monitor the repair site and aortic dimensions.

CoA is a congenital structural defect that cannot be prevented through lifestyle or behavioral measures. Prenatal diagnosis: fetal echocardiography is recommended at 18-22 weeks gestation in pregnancies with family history of congenital heart disease, known chromosomal abnormalities (Turner syndrome, 22q11 deletion), or maternal diabetes — early diagnosis enables planned delivery at a center with neonatal cardiac surgical capabilities, preventing cardiovascular collapse at ductus closure. Genetic counseling is appropriate for parents who have had one child with CoA (sibling recurrence risk approximately 2-4%). Girls with Turner syndrome (45,X) should undergo cardiac echocardiography at diagnosis — CoA is found in up to 35%. Once CoA is diagnosed and repaired, prevention of long-term complications is paramount through lifelong surveillance, blood pressure control, bicuspid aortic valve monitoring, and management of modifiable cardiovascular risk factors including smoking cessation, lipid control, and diabetes prevention — CoA patients face an inherently elevated risk of premature atherosclerotic cardiovascular disease even after successful repair.

Seek urgent evaluation for: any neonate with sudden cardiovascular deterioration — pallor, poor perfusion, absent femoral pulses, and respiratory distress in the first week of life — which may represent closing ductus and undiagnosed CoA; this is a cardiac emergency requiring immediate prostaglandin E1 and specialist cardiology assessment. In older children and adults, see a cardiologist for: unexplained upper limb hypertension especially in the young (under age 35); blood pressure difficult to control on multiple medications; diminished or delayed femoral pulses; continuous murmur heard in the upper back; or CoA found incidentally on chest CT or MRI performed for another indication. Patients with established CoA — repaired or awaiting repair — must attend scheduled follow-up and must not miss annual BP assessments and periodic cardiac MRI. Women with repaired CoA who are planning pregnancy require pre-pregnancy cardiology assessment — pregnancy substantially increases cardiovascular risk and risk of aortic dissection, particularly if hypertension or aortic aneurysm is present at the repair site.