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Coarctation of the Aorta

Coarctation of the Aorta is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • Coarctation of the aorta (CoA) is a narrowing of the descending aorta typically at the aortic isthmus, the region where the ductus arteriosus inserts just distal to the left subclavian artery.
  • The lesion is congenital in etiology. Rare cases of acquired coarctation have been reported.
  • Types include discrete juxtaductal (pre- and postductal), aortic arch hypoplasia, and complex with other cardiac lesions.
  • CoA causes outflow obstruction and hypertension (HTN) proximal to the site of coarctation with resultant left ventricular pressure overload, myocardial hypertrophy, and possible congestive heart failure.
  • Diagnosis may be missed or delayed due to the indolent nature of symptoms.
  • Clinical presentation varies from heart failure and shock in infants to asymptomatic HTN in older children and adults.
  • Treatment is usually surgical.
  • 75% of patients die by 46 years of age without repair.
Pediatric Considerations
  • CoA can be easily missed in the newborn period.
  • Neonatal coarctations are often missed secondary to a patent ductus arteriosus (PDA) which can obscure the anatomy. Also, the flow across the PDA makes it difficult to obtain an accurate Doppler gradient across the aortic isthmus during echocardiography.
  • Pulse oximetry screening for critical congenital heart disease in neonates only detects a minority of coarctations.
  • Upper extremity HTN and delayed femoral arterial pulses may not be present soon after birth and may be difficult to assess in neonates. Also, there is not a characteristic murmur making the diagnosis challenging.
  • This condition is a common cause of neonatal shock and death, especially if critical coarctation is present. Therefore, immediate medical and surgical intervention must be provided.
Pregnancy Considerations
  • Uncorrected coarctation or restenosis carries a high risk of aortic rupture or dissection and cerebral hemorrhage.
  • Even with correction, there is a higher incidence of miscarriage and preeclampsia during pregnancy.

Epidemiology

Incidence
  • More common in fall and winter births
  • Predominant age: infants and children
  • 4 in 10,000 live births

Prevalence
  • Accounts for 5–8% of all congenital heart defects
  • Sex predilection: male > female (2 to 5:1)
  • Mostly sporadic, with rare familial occurrences

Etiology and Pathophysiology

  • Two theories include hemodynamic alterations in intrauterine blood flow causing altered flow through the aortic arch and decreased isthmic flow leading to underdevelopment of the fetal aortic arch versus migration of ductus arteriosus tissue into the lumen of the fetal aorta causing narrowing as the ductal tissue contracts.
  • As the PDA closes, the gradient across the coarctation increases leading to an increase in left ventricular pressure load and to the evolution of collateral blood vessels.
  • Histologic findings demonstrate medial thickening, cystic medial necrosis, and intimal hyperplasia at the coarctation site.

Genetics
  • No specific inheritance pattern, but there is an increased familial risk for other congenital left heart abnormalities: bicuspid aortic valve, aortic stenosis, and hypopplastic left heart syndrome
  • There is a 5–15% incidence with Turner syndrome.
  • NOTCH 1 mutations have been identified in patients with left-sided obstructive lesions such as CoA.

Risk Factors

  • Male gender
  • Family history of left ventricular outflow tract obstruction
  • Turner syndrome

Commonly Associated Conditions

  • Bicuspid aortic valve: 85%
  • PDA: 65%
  • Ventricular septal defect: 30–35%
  • Mitral valve abnormalities (mitral valve stenosis)
  • Turner syndrome
  • Atrioventricular septal defects
  • Transposition of the great vessels or double outlet right ventricle
  • Aneurysm of circle of Willis: 3–5%
  • Intercostal aneurysms
  • Neurofibromatosis I (coarctation of abdominal aorta)
  • PHACE syndrome, Williams syndrome: rare conditions

General Prevention

  • If routine midtrimester obstetric ultrasound reveals extracardiac anomalies or a cardiac defect, fetal echocardiography is indicated given the increased risk of CHD (1)[B]. It should be performed between 18 to 22 weeks of gestation (1).
  • Other indications for fetal echocardiography include conditions with >2% absolute risk for CHD such as maternal diabetes mellitus, conception via assisted reproductive technology, and CHD in a first-degree relative (1).
  • Prenatal diagnosis of CoA is challenging because only a small percent of cardiac output flows through defect, and the PDA can make the aortic isthmus appear larger than it truly is.

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Citation

Stephens, Mark B., et al., editors. "Coarctation of the Aorta." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816216/all/Coarctation_of_the_Aorta.
Coarctation of the Aorta. In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816216/all/Coarctation_of_the_Aorta. Accessed April 19, 2019.
Coarctation of the Aorta. (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816216/all/Coarctation_of_the_Aorta
Coarctation of the Aorta [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 April 19]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816216/all/Coarctation_of_the_Aorta.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Coarctation of the Aorta ID - 816216 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816216/all/Coarctation_of_the_Aorta PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -