Coarctation of the aorta refers to a congenital narrowing of the aorta and is relatively common, accounting for 7% of cases of congenital heart disease.
Prenatal diagnosis is generally possible following the discovery of asymmetry of the ventricles and outflow tracts.
There is a strong association with chromosomal abnormalities, particularly Turner syndrome, as well as other cardiac and extracardiac malformations.
Prenatal diagnosis is critical, as it leads to significantly improved neonatal morbidity and mortality.
Following prenatal diagnosis, the infant should be delivered under controlled circumstances with prompt pediatric cardiology backup and the ability to start a prostaglandin infusion.
Definitive therapy in infancy involves surgical correction by means of aortic resection and end-to-end anastomosis, although there is a growing role for catheter-based therapy with a combination of balloon dilation and stent placement.
Coarctation of the aorta refers to narrowing of a segment of the aorta along the aortic arch, usually near the origin of the ductus arteriosus (Figure 51-1A and 51-1B). The narrowed segment of the aorta can be of any length and can be preductal, juxtaductal, or postductal in location. The area of narrowing can be caused by a discrete soft tissue shelf, or can be due to hypoplasia of a segment of the arch, leading to complete aortic arch interruption. Previously, coarctation was divided into infantile and adult forms. The infantile form classically occurred in a preductal location, was associated with other cardiac malformations, and was more likely to be associated with neonatal congestive heart failure. The adult form classically occurred in juxtaductal or postductal locations and was associated with a better prognosis. This distinction now seems to be imprecise and is of little relevance, with both forms of coarctation presenting at various ages.
A. Parasagittal image of a normal aortic arch; B. Parasagittal view of the aortic arch demonstrating narrowing in the distal portion of the transverse arch consistent with coarctation of the aorta.
The pathogenesis of coarctation is unclear. It may be due to a developmental defect of the aortic arch, possibly because of failure of connection of the fourth and sixth branchial arches to the descending aorta. Another possible mechanism is the development of abnormal blood flow patterns in utero, leading to decreased aortic-arch flow and increased flow in the pulmonary artery and ductus arteriosus. The consequence of this imbalance in flow may be the development of relative hypoplasia of the aortic arch. A third possible mechanism for the pathogenesis of coarctation is the presence of aberrant ductal tissue in the arch, leading to narrowing of the aortic arch after closure of the ductus (Whitley and Perry, 1990).
Associated cardiac malformations are present in up to 90% of cases of coarctation, including bicuspid aortic valve, aortic stenosis (see Chapter 50) ...