Aortic Coarctation

Narrowing of the aortic isthmus, just beyond the left subclavian artery near the ductus arteriosus. About 5 to 8% of congenital heart disease, male to female about 2:1.

• Associations: bicuspid aortic valve (about half or more), Turner syndrome, ventricular septal defect, hypoplastic arch, intracranial aneurysm (about 3 to 10%).
• Mechanism: ductal tissue extending into the aortic wall or reduced fetal flow; obstruction raises upper body pressure and drives collateral formation. In neonates, systemic flow beyond the narrowing depends on the ductus.
• Untreated, most adults die by the fifth or sixth decade from heart failure, dissection, cerebral haemorrhage or endocarditis. Operative mortality is less than 1 to 2% beyond infancy.

• Neonates with critical coarctation: collapse at ductal closure (days 2 to 14), poor feeding, tachypnoea, acidosis, shock, absent femoral pulses.
• Children and adults: upper limb hypertension, headache, epistaxis, cold legs, leg fatigue or claudication, radio femoral delay, arm to leg systolic pressure difference of 20 mmHg or more, interscapular systolic murmur, collateral murmurs, rib notching on X-ray (older than about 5 years).
• Complications: left ventricular hypertrophy, heart failure, dissection, cerebral haemorrhage, endocarditis, premature coronary disease.
• Differential diagnosis: Takayasu arteritis, interrupted aortic arch, pseudocoarctation, mid-aortic syndrome, neonatal sepsis or other left heart obstruction, atherosclerotic aortic obstruction.

• Measure BP in both arms and a leg; in neonates compare right hand and foot oxygen saturation.
• ECG: left ventricular hypertrophy. Chest X-ray: "3 sign", rib notching.
• Echocardiography (suprasternal view): narrowing with continuous Doppler flow and diastolic tail in the descending aorta; also look for bicuspid valve, ventricular septal defect, left ventricular function.
• CT or MR angiography defines site, length, collaterals and the arch. Catheter peak-to-peak gradient of 20 mmHg or more, with imaging narrowing, is significant.
• MR angiography of the head for intracranial aneurysm in adults; karyotype for girls with features of Turner syndrome.

• Neonatal shock: alprostadil (prostaglandin E1) 0.05 to 0.1 micrograms/kg/min IV to reopen the ductus, then reduce to 0.01 to 0.05 micrograms/kg/min; be ready to ventilate because apnoea is common. Dopamine 5 to 10 micrograms/kg/min for poor output, furosemide 1 mg/kg IV for pulmonary oedema, correct acidosis with adequate ventilation. Avoid high oxygen concentrations. Definitive surgical repair (extended end-to-end anastomosis) within days.
• Repair indications in older children and adults: peak-to-peak gradient 20 mmHg or more with upper limb hypertension, abnormal exercise BP response, left ventricular hypertrophy, or marked narrowing with extensive collaterals.
• Methods: surgical repair (end-to-end anastomosis, patch, interposition graft or bypass) for infants and complex arch disease; covered stent angioplasty for adolescents and adults with suitable anatomy; balloon angioplasty alone in infants has high recurrence and is used for recoarctation.
• Early post-repair paradoxical hypertension: esmolol 50 to 200 micrograms/kg/min IV or labetalol 20 to 80 mg IV, then oral beta blocker.
• Hypertension (persists in up to half after repair): bisoprolol 2.5 to 10 mg daily or metoprolol succinate 50 to 200 mg daily; ramipril 2.5 to 10 mg daily (check for renal artery involvement); amlodipine 5 to 10 mg daily. Target BP less than 130/80 mmHg, including during exercise.
• Special groups: pregnancy (repaired without residual gradient has low risk; unrepaired has high dissection risk; use labetalol, avoid ACE inhibitors); children (specialist cardiac centre, growth matched intervention); elderly (stenting preferred where feasible).
• Complications: recoarctation, aneurysm or pseudoaneurysm at the repair site, stent fracture, dissection, persistent hypertension, spinal cord ischaemia (surgery), endocarditis.
• Red flags: sudden chest or back pain, neurological deficit, haemoptysis (aneurysm rupture), fever with a murmur, refractory hypertension.
• Follow up for life: BP including arm to leg difference, echocardiography, and CT or MR angiography every 3 to 5 years to detect recoarctation (gradient 20 mmHg or more) and aneurysm; antibiotic prophylaxis for dental procedures after prosthetic material (amoxicillin 2 g orally 30 to 60 minutes before).