Aortic Arch Variants and Anomalies: Embryology, Imaging Findings, and Clinical Considerations

There is a wide spectrum of congenital anomalies or variations of the aortic arch, ranging from non-symptomatic variations that are mostly detected incidentally to clinically symptomatic variations that cause severe respiratory distress or esophageal compression. Some of these may be accompanied by other congenital heart diseases or chromosomal anomalies. The widespread use of multidetector computed tomography (CT) in clinical practice has resulted in incidental detection of several variations of the aortic arch in adults. Thus, radiologists and clinicians should be aware of the classification of aortic arch anomalies and carefully look for imaging features associated with a high risk of clinical symptoms. Understanding the embryological development of the aortic arch aids in the classification of various subtypes of aortic arch anomalies and variants. For accurate diagnosis and precise evaluation of aortic arch anomalies, cross-sectional imaging modalities, such as multidetector CT or magnetic resonance imaging, play an important role by providing three-dimensional reconstructed images. In this review, we describe the embryological development of the thoracic aorta and discuss variations and anomalies of the aortic arch along with their clinical implications.

Neonates with Right Aortic Arch Requiring Arch Reconstruction: A Single-Institution Experience

BACKGROUND

Reconstruction of a right aortic arch (RAA) is rarely required in the newborn period and has rarely been reported.

METHODS

All patients who underwent a RAA repair in the neonatal period from a single institution were retrospectively reviewed. The primary outcome measures included survival, complications, and reintervention.

RESULTS

Between 1984 to 2020, 15 patients were identified. Nine patients (60%) presented with an interrupted aortic arch (IAA), five (33%) with a hypoplastic arch, and one (7%) with anomalous origin of the brachiocephalic vessels. All patients had associated complex congenital heart disease. Median age at surgery was six days (range, 2-29), median weight 3.11 kg (range, 2.5-4.18). Genetic syndromes were prevalent and 77% of IAA patients had DiGeorge syndrome. Surgical techniques included end-to-side (27%), end-to-end (27%) or side-to-side anastomosis (13%) and placement of an interposition graft (7%). 65% required patch augmentation. Median intensive care unit and total hospital length of stay were 20 days (range, 7 - 92) and 28 days (range, 10 - 240), respectively. At median follow-up of 3.97 years (range, 0.19-36), 13 of 15 (87%) patients were alive. Vocal cord paralysis was found in 27%, hemidiaphragm paralysis in 13% and significant airway compression in 27%. Overall, 27% patients required reintervention on the aortic arch; two surgical and two percutaneous balloon dilation.

CONCLUSIONS

RAA reconstruction in the newborn period is rare and associated with complex lesions with an acceptable reintervention rate.

High prevalence of early arch reobstruction after arch repair in patients with anomalous right subclavian artery

OBJECTIVES

Having an anomalous right subclavian artery has been quoted to be a risk factor for early and late adverse events. We wanted to determine the rate of adverse outcomes in patients who have undergone arch repair with an associated anomalous right subclavian artery.

METHODS

The follow-up of 76 patients, with an anomalous right subclavian artery, who underwent arch repair at a single institution for various indications between 1981 and 2017 was reviewed.

RESULTS

There were 12 patient deaths. Twenty-three patients required an aortic arch reintervention (17 surgeries, 2 of which were indicated for bronchial obstruction). At last follow-up, 8 of 54 surviving patients (15%) had arch reobstruction (peak gradient >25 mmHg or reintervention). Freedom from aortic arch obstruction at 10 and 15 years was 51% [95% confidence interval (CI) 36-65%] and 35% (95% CI 19-51%), respectively. Neither the complete resection of the adjacent ridge nor the detachment and reimplantation of the anomalous subclavian vessel seemed to have an impact on the rate of reobstruction [hazard ratio (HR) 1.6, 95% CI 0.77-3.5; P = 0.2 and HR 0.61, 95% CI 0.083-4.5; P = 0.6, respectively].

CONCLUSIONS

Patients with an anomalous right subclavian artery are at risk of arch reobstruction necessitating reintervention but long-term follow-up was unable to demonstrate the mechanism of this obstruction in patients with this anomaly.

Neonatal repair of right interrupted aortic arch with cerebro-myocardial perfusion technique

Right interrupted aortic arch and descending aorta is exceedingly rare and most likely cause respiratory presentation, since patent ductus arteriosus (PDA) courses over the right mainstem bronchus. We report a case of successful neonatal biventricular repair of a right interrupted aortic arch (type B), with an aberrant right subclavian artery ventricular septal defect (VSD) in a 2.7 kg term neonate with DiGeorge syndrome. Patient presented in severe respiratory distress and acidosis at one day old. Two-dimensional (2D) echocardiography revealed aortic arch interruption beyond the common carotid arteries with large perimembranous outlet VSD. Aortic annulus diameter was 4.8 mm and there was no left ventricle (LV) outflow tract obstruction. Three-dimensional (3D) CT-scan confirmed these findings and identified a right-sided ductal arch that continued over the right mainstem bronchus into a right-sided descending aorta and aberrant right subclavian artery. Brachiocephalic perfusion and ductal perfusion was employed for cooling during cardiopulmonary bypass. Under deep hypothermia (27 °C rectal temperature), selective cerebro-myocardial perfusion was used for successful aortic arch repair without sacrificing the aberrant right subclavian artery. A direct tension-free anastomosis was attained. Her postoperative course was uneventful and her respiratory symptoms disappeared postoperatively. Early surgical correction is mandatory for these patients with unique anatomy and presentation.