Images in Cardiovascular Medicine A Phantom Case of Coarctation of the Aorta

9-month–old infant girl was referred for managementof transverse aortic arch hypoplasia in the setting of aright arch with mirror-image branching of thebrachioce-phalic vessels and an aberrant left subclavian artery originat-ing from the descending aorta. Because she was asymptom-atic and without left ventricular hypertrophy onechocardiogram, no interventions were undertaken. At mul-tiple subsequent clinic visits through 4 years of age, extremitypulses and blood pressures continued to be normal and equaldespite persistent arch hypoplasia and Doppler evidence ofarch obstruction on serial echocardiograms.At 4.5 years of age, her left radial pulse was noted to berelatively weaker for the first time, but 4-extremity bloodpressures remained equal. An echocardiogram with Dopplerrevealed a continuous systolic-diastolic forward flow wave-form in the abdominal aorta. One year later, her left radialpulse remained relatively weak, and her right leg systolicblood pressure was 30 mm Hg lower than that in her upperextremities. These findings prompted magnetic resonanceangiography, which revealed a complex form of right aorticarch with moderate transverse aortic arch hypoplasia measur-ing 6 mm in diameter, narrowing to 4 mm at the isthmus.Distal to the coarctation, the proximal descending aorta was11 mm in diameter. Both common carotid arteries aroseproximal to the hypoplastic transverse aortic arch. There wereno significant aortic-intercostal collateral arteries (Figure 1and online-only Data Supplement Movie I).Aortic angiography at the time of interventional catheter-ization confirmed the magnetic resonance angiography find-ings and also revealed delayed filling of the left vertebral andaberrant left subclavian arteries from collateral circulation,presumably through the circle of Willis (Figure 2 andonline-only Data Supplement Movie II). This retrograde flowthrough the left vertebral artery contributed to blood flowentering the descending aorta (Figure 3 and online-only DataSupplement Movie III).After reviewing these findings with the cardiovascularsurgery team, we elected to place a transcatheter stentacross the narrowest part of the coarctation (marked with a in Figure 2), reducing the pressure gradient from 30 to10 mm Hg (Figure 4). After the stent was placed, improvedantegrade flow in the aberrant left subclavian artery wasalso established (online-only Data Supplement Movie IV).Coarctation of a right aortic arch is an extremely rareanomaly. In a review of 240 patients with a right aortic arch,4.1% had coarctation, of whom 60.0% had an aberrant leftsubclavian artery or retroesophageal diverticulum of Kom-merell similar to this patient.