Coarctation of the Aorta

Coarctation of the aorta (CoA) is a congenital condition characterised by a narrowing of the aorta, usually near the insertion of the ductus arteriosus (ligamentum arteriosum after regression).

This narrowing forces the left ventricle to work harder to pump blood through the aorta, potentially leading to a lack of blood flow to the lower body if the narrowing is severe. The condition is more common in boys and is frequently associated with Turner syndrome.

Classification

Coarctation of the aorta can be classified into three types:

1. Preductal Coarctation: The narrowing is proximal to the ductus arteriosus. Blood flow to the aorta distal to the narrowing is dependent on the ductus arteriosus, making severe coarctation life-threatening.
2. Ductal Coarctation: The narrowing occurs at the insertion of the ductus arteriosus, typically appearing when the ductus arteriosus closes.
3. Postductal Coarctation: The narrowing is distal to the ductus arteriosus insertion. This type is most common in adults and can lead to hypertension in the upper extremities and weak pulses in the lower extremities.

Signs and Symptoms

In mild cases, children may show no signs or symptoms initially, and the condition might not be diagnosed until later in life. Symptoms in more severe cases include breathing difficulties, poor appetite, and failure to thrive. Older children may experience dizziness, shortness of breath, chest pain, fatigue, headaches, nosebleeds, and cold or painful legs. Classic signs include arterial hypertension in the arms with low blood pressure in the lower extremities and weak femoral pulses.

Diagnosis

Diagnosis can be made through imaging techniques. Resorption of the lower ribs due to increased blood flow and a classic 'figure 3 sign' on x-ray are indicative. Magnetic resonance angiography (MRA) is highly accurate for diagnosing CoA. Echocardiograms may be inconclusive in teenagers and adults. Severity is assessed by measuring the aortic cross-sectional area and mean heart rate–corrected flow deceleration in the descending aorta.

Treatment

Treatment varies depending on the severity and symptoms. Conservative management is recommended if asymptomatic. Surgical resection of the narrow segment or angioplasty with or without stent graft placement may be required if arterial hypertension or severe narrowing is present. Experimental treatments for high-risk foetuses involve maternal oxygen inhalation to increase blood flow through the underdeveloped aortic arch.

Complications of Surgery

Complications specific to surgical treatment include left recurrent nerve palsy and chylothorax. Chylothorax is managed conservatively by diet adjustments or, if necessary, surgical intervention.

Prognosis

Long-term outcomes are generally favourable, but some patients may develop re-narrowing or dilation at the repair site. Regular follow-ups in specialised congenital heart disease centres are essential for monitoring potential complications like late hypertension and recoarctation. Life expectancy and quality of life are generally normal if the repair is done early in life.

History

Coarctation of the aorta was largely unidentified until the mid-20th century. The first surgery for CoA was performed in 1944 by Clarence Crafoord and G. Nylin in Sweden. Historical cases of CoA have been identified via post-mortem records dating back as far as 1791.

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Self-assessment MCQs (single best answer)

What is Coarctation of the Aorta (CoA)?

Which population is more commonly affected by Coarctation of the Aorta?

What syndrome is frequently associated with Coarctation of the Aorta?

In which type of CoA is the narrowing proximal to the ductus arteriosus?

Which imaging technique is highly accurate for diagnosing Coarctation of the Aorta?

What is a classic sign of Coarctation of the Aorta on an x-ray?

Which treatment may be required if severe narrowing or arterial hypertension is present in CoA?

What is a potential complication specific to surgical treatment for CoA?

Why are regular follow-ups essential for patients who have undergone CoA repair?

When did the first surgery for Coarctation of the Aorta take place?