Congenital coarctation of the aorta (CoA) is a localized narrowing of the aortic lumen. It is a congenital cardiovascular malformation, accounting for approximately 5%-8% of all congenital heart diseases, with a male-to-female ratio of 3-5:1.
Pathological Anatomy
CoA can be classified into two types based on the location of the narrowing relative to the ductus arteriosus:
- Preductal CoA
- Postductal CoA
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Pathophysiology
The primary pathophysiological feature of CoA is hypertension in the systemic circulation proximal to the narrowing, affecting areas supplied by the aorta above the coarctation. This includes elevated blood pressure in the upper limbs and decreased blood pressure in the lower limbs, which are distal to the coarctation.
Clinical Manifestations
Many adult patients with CoA remain asymptomatic. However, some may experience exertional dyspnea, headaches, dizziness, epistaxis, weakness, numbness, coldness in the lower limbs, or even intermittent claudication.
Key signs include:
- Elevated blood pressure in the upper limbs and reduced blood pressure in the lower limbs
- Enhanced apical impulse and leftward cardiac enlargement
- A mid-to-late systolic ejection murmur heard along the left sternal border and upper abdomen, and sometimes over the left side of the back
- Approximately 20% of patients also with patent ductus arteriosus (PDA)
Auxiliary Examinations
Electrocardiography (ECG)
Common findings include left ventricular hypertrophy and/or myocardial strain.
Chest X-ray
Findings may include left ventricular enlargement, widening of the ascending aorta, and post-stenotic dilation of vessels above and below the coarctation, forming the characteristic figure 3 sign of the aortic arch.
Echocardiography
Echocardiography can measure the pressure gradient across the coarctation.
Aortic CTA (Computed Tomography Angiography)
It provides detailed visualization of the entire aorta, including the anatomy of the coarctation and collateral circulation.
Cardiac Catheterization and Aortography
They are useful for measuring pressure gradients, identifying the location and length of the coarctation, assessing collateral circulation, and determining the presence of a patent ductus arteriosus.
Diagnosis
Significant differences in blood pressure between the upper and lower limbs, combined with chest murmurs, strongly suggest CoA. Echocardiography is confirmatory.
Differential Diagnosis
Differentiation includes:
- Aortic valve stenosis
- Patent ductus arteriosus
- Takayasu arteritis
Treatment
Treatment options include interventional therapy and surgical therapy.
The standard approach involves resection of the coarctation and end-to-end anastomosis or patch repair. Postoperative complications may include aneurysm formation. Early surgical intervention is associated with better outcomes.
Prognosis
Surgical mortality is higher in adults compared to children. Without surgery, most patients die before the age of 50, with more than half dying before the age of 30.