8th March 2024

Coarctation of the Aorta

Introduction

Coarctation of the aorta (CoA) is a congenital stenosis which forms in the region of the ligamentum arteriosum at the descending aorta. It accounts for 4-6% of all congenital cardiovascular defects, with a prevalence of approximately 4 per 10,000 live births. Most cases are sporadic, with a male predominance. The severity of CoA depends on the degree of coarctation and narrowing. As a response to increased left ventricular afterload from left ventricular outflow tract obstruction, remodelling in the form of left ventricular hypertrophy occurs. There is also development of collateral blood supply from the mammary, intercostal and scapular vessels to bypass the stenosis. Amongst patients with CoA, up to 85% of patients have a bicuspid aortic valve (mainly fusion of the left and right coronary cusps). 

Up to 35% of patients with Turner’s syndrome have CoA. Other associated abnormalities include: 

• Ventricular septal defect
• Patent ductus arteriosus 
• Valvular and subvalvular aortic stenosis 
• Congenital mitral valve abnormalities 
• Aneurysm of the Circle of Willis 
• Aortopathies (aortic aneurysm and dissection) 
• Collateral circulation within the spinal canal causing spinal subarachnoid haemorrhage

Clinical presentation

Most adults remain asymptomatic unless severe hypertension develops, which may lead to headaches and epistaxis. Lower limb claudication may also develop due to reduced blood flow. Typical findings on examination include hypertension of the upper limbs, diminished blood pressure of the lower limbs and radio-femoral delay. An ejection systolic murmur can be heard anteriorly or posteriorly. A continuous murmur in the left parasternal border may also be heard due to the presence of large collateral vessels.

Investigations

The chest radiograph will show indentation of the aorta at the site of CoA and notching of ribs due to erosion by large collateral arteries.

Echocardiography provides information on the site and extent of CoA, as well as the presence of LVH and associated cardiac defects. Colour Doppler may show increased turbulence in the descending aorta. Cardiac catheterisation studies can demonstrate pressure gradients between the left ventricle and femoral artery. Imaging of the entire aorta is usually performed with CT or CMR. 

Management

In adult patients with CoA, transcatheter intervention using covered stents has become the first-choice treatment. The prognosis after CoA repair is generally good, with a >90% 10-year survival rate. It is important to note that CoA repair does not prevent the late recurrence of systemic hypertension. Patients should be reviewed regularly at the clinic and arterial hypertension should be treated according to the 2018 ESC guidelines. Echocardiography should be performed periodically for structural assessment post-repair.

The indications for intervention include radiological evidence of significant collateral flow; heart failure and systemic hypertension secondary to CoA, CoA with ≥50% narrowing relative to the aortic diameter and where the CoA gradient >20mmHg in hypertensive patients. 

Antibiotic prophylaxis is not recommended in CoA except for the first 6 months after stenting of CoA or if there has been a history of infective endocarditis. 

References

• Abbruzzese PA, Aidala E. Aortic coarctation: an overview. J Cardiovasc Med (Hagerstown). 2007;8(2):123-128. doi:10.2459/01.JCM.0000260215.75535.64
• Baumgartner H, De Backer J, Babu-Narayan SV, et al. 2020 ESC Guidelines for the management of adult congenital heart disease. Eur Heart J. 2021;42(6):563-645. doi:10.1093/eurheartj/ehaa554
• Canniffe C, Ou P, Walsh K, Bonnet D, Celermajer D. Hypertension after repair of aortic coarctation–a systematic review. Int J Cardiol. 2013;167(6):2456-2461. doi:10.1016/j.ijcard.2012.09.084