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Coarctation of the Aorta

Coarctatio aortae

For medical students2 min readUpdated 2026-10-10

Coarctation of the aorta is a congenital narrowing of the vessel at the transition from the aortic arch to the descending aorta. This condition leads to severe hemodynamic disturbances, including upper extremity hypertension and diminished lower extremity pulses.

LocalizationTransition of the aortic arch to the descending part
Upper extremity pressureElevated blood pressure (hypertension)
Lower extremity pressureDecreased blood pressure, weak pulses
CollateralsInternal thoracic and intercostal arteries

Anomaly and Hemodynamics

The anatomical feature involves the formation of a localized narrowing of the vascular lumen where the aortic arch transitions into the descending aorta. This obstruction to blood flow forces the cardiovascular system to operate under severe compensatory strain.

In response to the obstruction, left ventricular hypertrophy develops as the ventricle must overcome increased afterload. Clinically, this manifests as persistent hypertension in the upper extremities, while blood pressure drops and pulse strength diminishes in the lower extremities.

Compensatory Mechanisms

To supply the lower half of the body with blood despite the narrowed lumen of the main vessel, the body recruits alternative collateral pathways.

Cyanotic Variant ("Blue Type")

Medical literature distinguishes a specific variant of the pathology known as the "blue type" variant.

Its development is associated with an embryological leftward shift of the aortopulmonary septum. As a result of this anatomical defect, the pathological process is accompanied by marked left ventricular hypoplasia, shifting the main workload to the right ventricle, which develops compensatory hypertrophy.

Mnemonic

Hot top, cold bottom: upper extremity blood pressure is elevated, while lower extremity pressure drops due to the narrowing.

Frequently asked questions

What are the anatomical types of coarctation of the aorta based on its relationship to the ductus arteriosus?

Sources describe the following type of coarctation relative to the ductus arteriosus:

  • Infantile type (preductal) — localized proximal to the ductus arteriosus.

In this type, collaterals do not develop prenatally, and after birth, closure of the ductus arteriosus leads to a sharp reduction in blood supply to the distal segments.

What other congenital heart defects are most commonly associated with coarctation of the aorta?

Coarctation of the aorta is associated with the following congenital heart defects:

  • Bicuspid aortic valve.
  • Ventricular septal defect (VSD).
  • Hypoplastic left heart syndrome.

In the infantile type, 50% of cases show an association with other congenital heart defects, including a bicuspid aortic valve, VSD, and hypoplastic left heart syndrome.

What specific radiographic findings are characteristic of long-standing coarctation of the aorta?

Long-standing coarctation of the aorta is characterized by the following specific radiographic signs:

  • Rib notching (rib-notching) — bilateral notches on the inferior margins of the ribs, occurring secondary to the pressure of dilated intercostal arteries during the development of collateral circulation.
  • Alteration of the aortic arch — in the posteroanterior view, the aortic knuckle may appear small and flattened.
  • Dilatation of the internal thoracic artery (a. thoracica interna) — visualized retrosternally in the lateral view.
What life-threatening complications can develop in the natural history of untreated coarctation of the aorta?

The natural history of untreated coarctation of the aorta inevitably leads to fatal outcomes driven by the following life-threatening complications:

  • Heart failure — develops in later stages due to left ventricular pressure overload.
  • Aortic rupture and aortic dissection — severe vascular catastrophes.
  • Infective endocarditis — microbial infection of cardiac structures.
  • Intracerebral hemorrhage — occurs due to the rupture of associated cerebral aneurysms.
Where is the narrowing anatomically located in coarctation of the aorta?

The narrowing is localized in the region where the aortic arch transitions into the descending aorta.

Why does blood pressure drop in the lower extremities with this defect?

The drop in blood pressure and the weakening of pulsations in the legs are caused by the mechanical obstruction to blood flow at the site of the vascular narrowing.

Which vessels participate in forming collateral circulation?

Collateral blood flow develops through the system of the internal thoracic and intercostal arteries.

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