Right cervical aortic arch associated with anomaly of epiaortic vessels and haemodynamically significant obstruction between ascending and descending aorta. Extra-anatomic bypass graft between ascending and descending aorta and long-term follow-up

Abstract

Right cervical aortic arch is a rare malformation in which a right-sided aortic arch is unusually long, forms a loop, descends, and crosses behind the oesophagus to continue as a left descending aorta. We present a case of right cervical aortic arch associated with anomaly of epiaortic vessels and aortic obstruction, surgically treated with extra-anatomic bypass graft between ascending and descending aorta.

Cervical aortic arch is a rare congenital anomaly where the aortic arch is cranially situated above the level of the sternum and clavicles. It results from abnormal persistence of the third arch with involution of the left fourth arch. ¹

The prevalence of cervical aortic arch is less than 1 in 10,000 live births. ²

Cervical aortic arch can be an isolated anomaly or associated with other cardiac malformations, such as tetralogy of Fallot, pulmonary atresia, ventricular septal defect, ¹ bicuspid aortic valve, anomalies of epiaortic vessels, and persistent left superior vena cava. ³

Complications of cervical aortic arch include aneurysm formation (20% of cases), coarctation, and obstruction. ⁴

The clinical presentation of cervical aortic arch varies from asymptomatic form, diagnosed as incidental finding, to tracheal and/or oesophageal compression with dysphagia, dyspnoea, and recurrent pulmonary infections. ² During physical examination, the most common findings are a pulsatile cervical mass and a discrepancy of arterial blood pressure between upper and lower extremities.

Right cervical aortic arch is a further rare malformation in which a right-sided aortic arch is unusually long, forms a loop and ascends into the right supraclavicular region, then descends and crosses behind the oesophagus to continue as a left descending aorta. ²

Management depends on the anatomic pattern of the malformation. Surgical techniques include open repair (extra anatomic bypass graft between ascending and descending aorta) or endovascular treatment. ⁴

We describe a case of cervical aortic arch consistent with a type B ⁵ according to Haughton classification (supplementary table S1), complicated by significant obstruction between ascending and descending aorta. Our patient underwent surgical treatment with extra-anatomic bypass graft and she was long-term followed up.

The patient confirmed the permission to publish this case report.

Case report

In 2001, a 4-year-old girl was referred to our centre for a pulsatile mass at the right side of the neck. Physical examination revealed a thrill in the suprasternal region and at the base of the neck. All pulses were weakened, without pressure difference between lower and upper limbs. Patient’s weight was 15 kg.

Electrocardiogram showed sinus rhythm with normal heart rate.

Transthoracic echocardiogram revealed normal-sized cardiac chambers with normal biventricular function. The aortic arch appeared elongated and straight, but the anatomy was not clearly definable by ultrasounds.

Aortography with subtraction imaging and cardiac catheterisation confirmed the anomalous anatomy.

Our patient was diagnosed with right-sided cervical aortic arch with contralateral descending thoracic aorta, anomaly of epiaortic vessels, and severe aortic obstruction before the emergency of the left subclavian artery, at the level of the small, elongated, retroesophageal aortic arch.

The abnormal branching pattern of the epiaortic arteries is explained in Figure 1.

Figure 1. Right cervical aortic arch associated with anomaly of epiaortic vessels and obstruction between ascending and descending aorta. RCCA, right common carotid artery; RSA, right subclavian artery; LVA, left vertebral artery; LICA, left internal carotid artery; LECA, left external carotid artery; LSA, left subclavian artery; DA, descending aorta; *, extra-anatomic bypass graft between ascending and descending aorta.

The first aortic branch was the left common carotid artery. The second branching vessel was the right common carotid artery that originated at the apex of the cervical aortic arch, at the level of the second cervical vertebra.

The apex of the arch created an acute angle. The descending part of the arch re-entered into the superior mediastinum with a tortuous course, where it gave rise to the right subclavian artery and to a small right vertebral artery. The arch continued as a small retroesophageal vessel into the descending aorta. The left subclavian artery arose from the diverticulum of the left-sided portion of the descending aorta. The left vertebral artery originated from an anastomotic network of arterioles above the left subclavian artery.

During catheterisation our patient was diagnosed with severe obstruction between ascending and descending aorta (peak-to-peak gradient 30 mmHg).

Therefore, in 2001, considering the extremely complex vascular anatomy, the young girl underwent extra-anatomic bypass grafting to palliate the obstruction of the aortic arch. The intervention was performed with the combined posterolateral left thoracotomy (to anastomose the graft to the descending aorta) and longitudinal median sternotomy (to anastomose the graft to the ascending aorta), without the use of extracorporeal circulation. The bypass was successfully made with a 14 mm Dacron graft.

The girl had a normal linear and ponderal growth and a normal psychomotor development, without cardiovascular events.

In 2011, she was electively admitted to our hospital as a check-up.

The CT scan confirmed the patency of the extra-anatomic bypass graft. There was no evidence of a complete vascular ring, nor tracheal or oesophageal compression.

A cranial CT scan, as further diagnostic study, documented the anatomy of the intracranial vessels that formed a regular circle of Willis.

Her echocardiogram was normal, without signs of increased left ventricular mass.

The catheterisation demonstrated a good result of the extra-anatomic bypass graft (peak-to-peak gradient 10 mmHg).

Therefore, our patient continued her non-invasive follow-up. Ten years later, in September 2021, at the age of 23 years, she was re-evaluated. She was normotensive, without the need of drugs. Her blood tests, including estimated glomerular filtration rate, were normal. The CT scan (Fig 2; supplementary figure S2) showed moderate calcific degeneration of the prosthetic graft with a lumen reduction at its proximal anastomosis (minimal lumen diameter 8 mm). The descending part of the cervical aortic arch had a diameter of 14 mm, and it continued as a small retroesophageal vessel with a diameter of 9 mm. The diameter of the descending aorta was 16 mm.

Figure 2. Calcific degeneration of the extra-anatomic bypass graft at CT scan, lateral view.

The catheterisation confirmed the re-obstruction between ascending and descending aorta, with a peak-to-peak gradient of 25 mmHg.

Discussion

Although cervical aortic arch anomalies have been reported in literature, published reports of new cases will help to increase awareness regarding this anomaly.

We described a case of a right cervical aortic arch, associated with a complex anomaly of epiaortic vessels.

The severe aortic obstruction was treated with the technique of ascending-to-descending aorta bypass, which was effective and led to a regular linear and ponderale growth of our patient.

Twenty years after the operation, she was asymptomatic, without signs of organ damage, in particular neither cardiovascular nor renal damage.

During her follow-up, we invasively documented a significant recurrent obstruction at the level of the graft.

Considering the absence of signs and symptoms and the difficulties of a reintervention, this case is under collegial evaluation to recommend the best timing and treatment option to our patient.