Two-Stage Elephant Trunk Reconstruction for Aneurysm of an Aberrant Right Subclavian Artery in Association with Aneurysmal Distal Aortic Arch and Descending Thoracic Aorta

Abstract

Surgical treatment of the combination of aneurysms of an aberrant right subclavian artery, distal aortic arch, and descending thoracic aorta requires control of structures in both the right and the left hemithorax. We report a 2-stage surgical approach. The 1st stage, performed through a median sternotomy, consists of an elephant trunk reconstruction and an interposition graft to the ligated aberrant right subclavian artery. The 2nd stage, performed through a left thoracotomy, is an interposition graft from the elephant trunk to the distal descending thoracic aorta.

The most common anomaly of the aortic arch is an aberrant right subclavian artery that arises from the proximal descending thoracic aorta. This occurs in 0.5% of the population. ¹ This unusual aberrant vessel and the adjoining aorta are frequently subject to aneurysmal degeneration. ^2,3 Surgical treatment of such lesions requires control of vascular structures in both the right and the left hemithorax.

Harrison and colleagues ⁴ clearly describe general principles for surgical treatment of aneurysms of an aberrant right subclavian artery: 1) safe control and ligation of the origin of the aberrant subclavian; 2) avoidance of embolization of debris from within the aneurysm to the distal vertebrobasilar or subclavian circulation; 3) distal ligation of the subclavian artery aneurysm and restoration of blood flow to the distal right subclavian artery. If a conduit to the distal subclavian artery is not reconstructed, vascular insufficiency and subclavian steal may result. ²

When, in addition to the aneurysmal aberrant right subclavian artery, aneurysms are also present in the aortic arch and the descending aorta, concomitant surgical treatment can be complicated. We describe our 2-stage approach, which includes an elephant trunk reconstruction, for treating this combination of lesions.

Case Report

In September 1998, 56-year-old man presented with intermittent back pain. He was found to have a 4-cm aneurysm of an aberrant right subclavian artery and a 9-cm aneurysm of the distal aortic arch and descending thoracic aorta (Fig. 1). He also had a chronic aortic dissection (initially diagnosed 5 years previously), which originated at the aberrant subclavian artery and extended distally into the abdominal aorta. His aneurysms were symptomatic and required resection because of their size.

Fig. 1 Artist's drawing of a 4-cm aneurysm of an aberrant right subclavian artery and a 9-cm aneurysm of the distal aortic arch and descending thoracic aorta, as found in our patient.

A 2-stage elephant trunk repair was planned. The 1st stage was performed through a median sternotomy (Fig. 2). The aberrant right subclavian artery was exposed in the superior right mediastinum at its point of exit from the thorax. The patient was cooled to 18 °C, and the aberrant vessel was ligated. The circulation was arrested for 25 minutes, during which retrograde cerebral perfusion was administered.

Fig. 2 Artist's rendition of the 1st stage of the elephant trunk repair. The aberrant right subclavian artery was tied off distally. Under hypothermic circulatory arrest, the transverse aortic arch was opened with a longitudinal incision. Through this aortotomy, the origin of the aberrant right subclavian artery was oversewn and the elephant trunk graft was sewn in place. After the aortotomy was closed and the circulation was restarted, flow to the right subclavian artery was established by placement of an interposition graft.

Meanwhile, the transverse aorta was opened longitudinally. The origin of the aberrant right subclavian artery was oversewn. The proximal end of a 26-mm Dacron graft was sewn endoluminally into the aortic arch, proximal to the aneurysm. The distal end of the graft was placed within the true lumen of the aneurysm. The aorta was deaired, the transverse aortotomy was closed, and the circulation was restarted.

During rewarming, an interposition graft was sewn end-to-end from the ascending aorta to the distal right subclavian artery. Thus, during the 1st stage of the operation the aberrant right subclavian artery aneurysm was excluded from the circulation and blood flow to the distal right subclavian was established. This strategy also enabled safe and effective placement of the proximal anastomosis of the aortic graft within the aortic arch, thereby facilitating the 2nd stage of repair through a left posterolateral thoracotomy at a later date.

Discussion

The “elephant trunk” technique was 1st described by Hans Borst, who also coined the term. ⁵ Palma and co-authors ⁶ have described an elephant trunk technique for the treatment of acute type B aortic dissection. Ours is the 2nd report of a 2-stage elephant trunk repair of an aortic aneurysm associated with an aberrant right subclavian artery. Lee, Maughan, and Svensson ⁷ reported a 2-stage elephant trunk repair in which they re-established flow to a non-aneurysmal aberrant right subclavian artery aneurysm during the 2nd stage through a short interposition graft that originated from the graft to the descending aorta. Because our patient's aberrant right subclavian artery was aneurysmal, an interposition graft from the ascending aorta and exclusion of the aneurysm at the 1st stage was preferable.