Overview

Narrowing of the aorta at the aortic isthmus, which is a distal part of the aortic arch, close to the ductus arteriosus (juxtaductal) and left subclavian artery

Rarely, the coarctation is located in the thoracic or abdominal aorta

Prevalence: 4/10,000 live births

Sex: ♂ > ♀

Congenital

• The exact etiology is unclear

• Two etiological theories have been developed.

  • Hemodynamic: caused by underdevelopment of the aorta due to an abnormally decreased antegrade intrauterine blood flow

  • Ductal: caused by closure of the ductus arteriosus tissue that extends into the thoracic aorta

• Associated with Turner syndrome (in 5–15% of female patients with coarctation) [18][19]

• Often accompanied by a bicuspid aortic valve , VSD, and/or PDA

Acquired: e.g., Takayasu arteritis, severe atherosclerosis

Genetic defects and/or intrauterine ischemia → medial thickening and intimal hyperplasia forming a ridge encircling the aortic lumen → narrowing of the aorta → ↑ flow proximal to the narrowing and ↓ flow distal to the narrowing

• In preductal (infantile) type (most common type), the narrowing is proximal to the ligamentum arteriosum or ductus arteriosus.

• In postductal (adult) type, the narrowing is distal to the ligamentum arteriosum or ductus arteriosus.

In cases of discrete stenosis: Left ventricular outflow obstruction → myocardial hypertrophy and increased collateral blood flow (e.g., intercostal vessels, scapular vessels).

In long segment stenosis, compensatory mechanisms do not develop → closure of PDA after birth → left ventricular pressure and volume overload → hypoperfusion of organs and extremities distal to the stenosis