Coarctation of Aorta

Basics

DESCRIPTION

  • Discrete stenosis of the upper thoracic aorta, usually just opposite the site of insertion of the ductus arteriosus (juxtaductal). A segment of tubular hypoplasia and/or a remnant of ductal tissue give rise to a prominent posterior infolding (“the posterior shelf”).
  • The hemodynamic lesion is most often discrete but may be a long segment or tortuous in nature. It is usually juxtaductal but may occur in other sites (i.e., the abdominal aorta).
  • The prevalence of other associations (bicuspid aortic valve) and long-term complications (hypertension) indicate that this lesion may be part of a broader spectrum arteriopathy and/or endothelial disorder.

EPIDEMIOLOGY

PREVALENCE

  • ~6–8% of patients with congenital heart disease have coarctation.
  • More common in males

RISK-FACTORS

GENETICS

  • Occurs in 35% of patients with Turner syndrome (XO)
  • Has been described in cases of monozygotic twins
  • Mutations of several genes, including NOTCH1 and MCTP2, have been identified in some patients.
  • Many studies document the prevalence of a microdeletion at 22q11 in patients with arch anomalies and ventricular septal defects.

PATHOPHYSIOLOGY

  • Decreased systemic blood flow to lower body after ductal closure
  • Increased afterload to left ventricle (LV) causes LV hypertrophy. Relative underperfusion of the renal vessels, baroreceptors, and multiple other mechanisms combine to induce compensatory hypertension.
  • If the coarctation is severe, LV dysfunction and congestive heart failure (CHF) result, with low cardiac output and increased LV end-diastolic pressure.
  • Decreased myocardial perfusion may be present in cases of very low output.

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