Dysphagia Lusoria with atrial septal defect: Simultaneous repair through midline.

An aberrant right subclavian artery from the descending aorta is almost always reported as an isolated anomaly. We present the case of a four-year-old child with an anomalous origin of the right subclavian artery from the descending aorta, associated with an ostium secundum atrial septal defect. The patient underwent simultaneous repair of both the anomalies through median sternotomy, with implantation of the subclavian artery into the right common carotid artery. We believe that median sternotomy is the optimal surgical approach for the management of these lesions. Other operative approaches are also discussed.

INTRODUCTION

Various surgical approaches for aberrant right subclavian artery arising from the descending aorta and causing compressive symptoms have been described in the past. We describe our approach through median sternotomy to deal with this anomaly in association with an intra cardiac defect and believe that this is the optimal surgical approach in these patients.

CASE REPORT

A four-year-old female child presented to us with complaints of dysphagia and regurgitation of solid food. A contrast-enhanced CT scan (CECT) of the chest done elsewhere revealed an aberrant right subclavian artery [Figure 1]. A 256 slice CECT scan was ordered in our hospital for the exact anatomical characterization of the aberrant vessel. The scan showed an aberrant origin of the right subclavian artery from the medial wall of the descending thoracic aorta, just distal to the origin of the left subclavian artery [Figures 2 and 3]. The artery crossed to the right side at the level of the fourth thoracic vertebra, causing posterior compression of the esophagus. An additional finding that was noted was the common origin of the right and left common carotid arteries. The arch was left-sided, with a left descending thoracic aorta. An echocardiogram done showed a large ostium secundum atrial septal defect (ASD) of 20 mm, with a dilated right atrium and right ventricle.

Figure 1

CECT Chest (coronal cuts) showing posterior compression of the esophagus by the aberrant right subclavian artery

Figure 2

3-dimensional reconstruction of a 256-slice CECT showing a bicarotid trunk and aberrant origin of the right subclavian artery from the descending aorta (anterior view). RT SCA = Right subclavian artery; LT SCA = Left subclavian artery; RT CCA = Right common carotid artery; LT CCA = Left common carotid artery

Figure 3

3-Dimensional reconstruction of a 256-slice CECT showing an aberrant right subclavian artery from the descending aorta (posterior view). RT SCA = Right subclavian artery

Operative procedure

Under general anesthesia a median sternotomy was performed. The arch was followed down from the top and the aberrant right subclavian artery was identified just distal to the origin of the left subclavian artery on the medial wall of the descending thoracic aorta. Loss of the right radial artery trace on clamping the aberrant vessel confirmed that the vessel was indeed the right subclavian artery. The artery was carefully divided at its site of origin and the aortic end oversewn with two layers of continuous polypropylene sutures. The artery was next brought to the right side from behind the esophagus and the anastomosed end side to the right common carotid artery, after confirming that there was no torsion of the mobilized vessel [Figure 4]. Pericardial patch closure of the ostium secundum ASD was performed in a routine manner, under cardiopulmonary bypass, under mild hypothermia using the standard cannulation techniques. The patient had an uneventful postoperative course and was discharged on day six from the hospital. The patient had no complaints of dysphagia or regurgitation of food on discharge.

Figure 4

Surgical picture showing a re-implanted right subclavian artery onto the right common carotid artery

DISCUSSION

Bayford was the first to outline the anatomic abnormality and attribute the symptom of dysphagia to it. He termed it dysphagia lusus naturae meaning dysphagia caused by freak of nature.[1] In 1946, Gross reported the first successful surgical treatment for this anomaly by simple ligation and division.[2] The right subclavian artery from the descending aorta is the most common arch anomaly found in approximately 0.5 to 1.8% of the population.[3] The specific embryological abnormality is the involution of the fourth vascular arch, along with the right dorsal aorta, leaving the seventh inter-segmental artery attached to the descending aorta. As the persisting right aortic arch forms the root of the aberrant artery, the artery often has a broad base and is referred to as a ′Kommerell's diverticulum. This persistent inter-segmental artery assumes a retroesophageal position as it proceeds out of the thorax into the right arm.[4]

Patients with an anomalous right subclavian artery (ARSA) and left aortic arch (LAA) may have associated cardiac anomalies. In an autopsy study by Hugo Zapata and colleagues in 11,000 pathological specimens, ARSA with LAA was found in 128 specimens (1.2%). Of the 128 cases of ARSA, 117 occurred among 4102 instances of congenital heart disease. Among these 117, 38% had conotruncal anomalies, 21% had septal defects, 5% had right heart anomalies, and 8% had miscellaneous anomalies.[4]

Patients with this anomaly are usually asymptomatic.[5] Even though this condition is a congenital anomaly, patients usually do not present with it in childhood. They become symptomatic in young adulthood and even in middle or old age. The average age of presentation in these patients is 48 years.[5] Theories explaining this delayed presentation include physiological and anatomical changes that may occur with the aging process, such as, increased esophageal rigidity, rigidity of the vessel wall due to atherosclerosis, elongation of the aorta, and aortic aneurysm formation, especially in the presence of a Kommerell's diverticulum.[5]

Presence of a bicarotid trunk along with the presence of ASD makes this a still rarer presentation. In a study by Klinkhamer, which reviewed various case reports published, an aberrant right subclavian artery with a bicarotid trunk was seen in 29% of the cases of this branch anomaly.[6] In the absence of an aneurysm, it was the bicarotid trunk that accounted for the symptoms rather than the retroesophageal artery alone, by preventing the trachea and esophagus from bending forward to where the artery crossed.[6] A similar case in a 36-year-old woman was described by Rogers et al., where the symptoms were attributed to the bicarotid trunk rather than the artery alone.[7]

The Adachi Williams classification describes this case as type H, where the right subclavian artery is anomalous (as in type G), but there is a common carotid trunk. The subtypes within the group having abnormal branching patterns are CG, H, G, and N.[8]

Several approaches have been used in the past and are being used now for the surgical treatment of this anomaly. The supraclavicular approach on the side of the aberrant vessel can be used, as first described by Orvald and colleagues[9] and modified by Valentine and colleagues.[10] However, this approach may be useful only in cases requiring simple division and re-implantation of the subclavian artery, but an associated diverticulum or any other cardiac lesion cannot be dealt with through the same incision.

Smith[11] and Pifare described implantation of the subclavian artery onto the aorta via a left thoracotomy. This approach is technically challenging and involves passing the right subclavian artery and the graft from the posterior to the anterior mediastinum, as well as deep anastomoses.[11]

Bailey and other authors have described right posterolateral thoracotomy for implantation of the right subclavian artery to the ascending arch, which is much easier to perform. This approach has a disadvantage, in that, if the artery is not divided close to the origin, the residual stump may lead to persistent dysphagia.[12]

The median sternotomy approach was first described by Shumacker.[13] This approach is particularly beneficial if the patient has an associated intra-cardiac lesion, as in our patient. We believe that this is an ideal approach, as both the origin and the implantation sites are visualised satisfactorily, and bleeding can also be adequately controlled, with the possibility of institution of a cardiopulmonary bypass in case of inadvertent bleeding.

A case of right aortic arch, aberrant left subclavian artery, with an atrial septal defect was described by Geun Jin Ha et al., where a median sternotomy was used to repair the ASD, with associated tricuspid regurgitation.[14]

In conclusion, we believe that anomalous origin of the right subclavian artery from the descending aorta is a rare surgical cause of dysphagia. Various surgical approaches can be used, each with its own advantages and limitations. However, we believe that median sternotomy is an excellent approach, especially if there is an associated cardiac lesion.