Which is the most common abnormality associated with coarctation of the aorta?

Clinical Presentation

Etiology

The cause is unknown but attributed to perturbed prenatal arterial flow patterns at the junction of the proximal descending thoracic aorta (isthmus), patent ductus arteriosus, and postductal descending thoracic aorta.

There is often a relatively rapid obstructive exacerbation as the ductus arteriosus closes in the neonatal period.

Anatomy and Natural History

Coarctation of the aorta is typically a fibrous ridge in the aortic isthmus, just distal to the insertion of the left subclavian artery. Although often discrete, aortic coarctation can also be long segment or associated with a diffusely hypoplastic transverse aorta. Aortic coarctation is associated with a diffuse vascular abnormality and is associated with aortic aneurysm, cerebral aneurysms, or endothelial dysfunction.8 Awareness of these abnormalities is important because the entire aorta and cerebral vessels should be imaged in patients with aortic coarctation.

Aortic coarctation sometimes presents in adulthood as difficult-to-manage systemic hypertension and the diagnosis may be suspected from a murmur, diminished lower extremity pulses, or arm–arm or arm–leg blood pressure discrepancy. Those who had an aortic coarctation repair early in life have up to a 5% risk of re-coarctation in adulthood and present similarly.9

Coarctation of the Aorta

CoA can be either “simple” (isolated defect) or “complex” (associated with other intracardiac or extracardiac defects). A BAV occurs in 25% to 75% of complex CoA (Figure 11-7). The BAV accompanying CoA has been described as “equally bicuspid” with two symmetric sinuses of Valsalva.59 Morphologic analysis of the BAV has demonstrated increased frequency of fusion of the left and right coronary cusps in the presence of CoA.60 Identification of a BAV in patients with coarctation is vital as its presence confers a substantially increased risk for aortic dissection.34,61 In addition, valvular complications from the BAV such as aortic stenosis or regurgitation as well as ascending aortic aneurysm are more prevalent in subjects with both CoA and a BAV.62

Although patients with CoA are often diagnosed and treated at an early age, those individuals with a BAV require long-term follow-up of not only the coarctation repair but also of the BAV and ascending aorta.62,63 In one large series of patients who were operated on for CoA, 41% of reoperations were primarily for valvular indications.63 It is therefore imperative that these patients receive meticulous follow-up with routine radiographic and echocardiographic assessment.64

Coarctation of the Aorta

Coarctation of the aorta (CoA) is a discrete narrowing of the proximal descending aorta, and this lesion can be associated with mitral stenosis, aortic valvulopathy, VSDs, aortic arch abnormalities, or aberrant subclavian arteries. Patients with repaired CoA who are normotensive typically do well during pregnancy (Figure 2). Krieger et al. compared pregnancy and delivery outcomes between women with and without CoA in the NIS [69]. They found that women with CoA are more likely to have hypertensive complications of pregnancy [defined as pregnancy-induced hypertension, preeclampsia, and eclampsia (multivariate OR 3.6; 95% CI 2.5–5.2)], delivery by cesarean section (multivariate OR 2.0; 95% CI 1.4–2.8), and have adverse combined cardiovascular outcomes (multivariate OR 16.7; 95% CI 6.7–41.5). Patients with repaired and unrepaired CoA carry a risk of aortic dissection and aortic rupture [70, 71]. Infants born to mothers with CoA were found to have lower birth weight [72]. Interestingly, right ventricular dysfunction before pregnancy and at 20 weeks gestation was associated with impaired uteroplacental Doppler flow. Of note, a study of 28 women with CoA who had cardiac magnetic resonance imaging within 2 years of delivery had a higher risk of hypertensive events in pregnancy if they were found to have a minimum aortic diameter less than 12 mm; there may be a role for prepregnancy cardiac magnetic resonance imaging for risk stratification of CoA patients [73].

Incidence

Isolated COA is the fifth or sixth most common anomaly of all the congenital heart diseases, with estimates of 1 in 3000 to 4000 live births.38–41 In the New England regional study of congenital heart defects, COA accounted for 7.5% of anomalies in infants younger than 1 year of age.42 That may be an underestimation, since COA in newborn infants may not be detected because of similar blood pressure in the upper and lower extremities.43 The male-to-female ratio is 1.74:1.44 In older patients with isolated COA, the incidence is also higher in males. Most cases of COA appear to be sporadic, with no evidence of a mendelian pattern of inheritance.38 However, congenital heart disease has been reported in approximately 4% of the offspring of female COA patients.40 In addition, a recent nonparametric linkage analysis suggests a genetic basis for a subset of COA cases. McBride et al. demonstrated possible susceptibility loci on chromosomes 2p23, 10q21, and 16p12 in a cohort of 289 individuals from 43 separate families.40,45 Coarctation of the aorta is the most common cardiovascular defect found in Turner's syndrome. Noncardiac abnormalities that have been reported with COA are hypospadias, clubfoot, and ocular defects.44

Aortic coarctation

CoA is typically juxtaductal in location, involving the aortic isthmus. The length of the narrowed segment may be discrete or long-segment. Narrowing or hypoplasia of the transverse arch is more commonly found in patients presenting as fetuses or early in childhood, whereas discrete narrowing with the presence of collaterals is more often seen in patients presenting later. The vast majority of patients with CoA are now diagnosed as infants. The diagnosis of CoA is 1.7 times more common in males, but CoA occurs in 12% to 17% of patients with Turner syndrome.21 In several large series of patients with CoA, 14% to 27% had significant AS or aortic regurgitation.22–24 Complications are common in patients following CoA repair, and age at repair appears to be a risk factor. Late cardiovascular complications include systemic hypertension, recoarctation, dissection, aneurysm, rupture, and early coronary artery disease.25

The hallmark of CoA is luminal narrowing of the aorta due to a posterior “shelf” or a circumferential membrane. A helpful anatomic definition of narrowing is a diameter of the proximal transverse arch 60% or less of the ascending aorta diameter, distal transverse arch 50% or less, or isthmus 40% or less.26 Echocardiography is a useful diagnostic tool for CoA, but imaging of the aortic isthmus and proximal descending aorta is difficult in older children and adults (Fig. 167.2, A/Video 167.2, A). In those cases, other imaging modalities such as magnetic resonance imaging (Fig 167.2, B/Video 167.2, B) or computed tomography are indicated.

Goals of the echocardiographic examination include evaluation of aortic arch sidedness and branching pattern, severity and length of CoA, size of other aortic segments (including aneurysms), other left-sided structures (including AoV morphology), collaterals, LV size and function (including LV mass), and associated lesions. The arch is best visualized from suprasternal and high left sternal border windows, but it may be seen in neonates even from the subcostal window. Aortic branching is evaluated in suprasternal short-axis imaging, with a normal pattern visualized as a bifurcating first brachiocephalic artery to the right (opposite to the sidedness of the arch). Absence of normal bifurcation may raise the suspicion of an aberrant right subclavian artery. The region of the CoA and proximal descending aorta is sometimes better seen in a sagittal plane at the high left sternal border window using the main pulmonary artery as a “window” for imaging. A juxtaductal CoA can involve the origin of the left subclavian artery. If present, an aberrant subclavian artery may be above or below the site of CoA.

What is associated with coarctation of the aorta?

What is the most common abnormality of the aorta?

What are associated cardiac anomalies in coarctation?

What are common symptoms of coarctation of the aorta in children?