Fate of Extra-anatomic Aortoaxillary Bypass for Facilitation of Frozen Elephant Trunk Surgery in Zone 2: Midterm Results

Objectives: Frozen elephant trunk (FET) surgery enables one-stage treatment of the aortic arch and the descending aorta but is associated with a major surgical trauma. In order to reduce the duration and trauma of extracorporeal circulation and hypothermic circulatory arrest (HCA) the zone-2 arch repair technique in combination with left subclavian artery (LSA) debranching was introduced. Anastomosis of a vascular graft at the left–axillary artery prior to sternotomy enables first, a single ligature of the LSA for debranching during the opened arch repair and second, selective perfusion of LSA and collateral arteries during HCA. The study presents the first midterm results with regard to patency of the aortoaxillary bypass and related complications.

Methods: Between December 2010 to August 2019 158/254 patients (age 60 ± 11 years, 68% male) operated by FET underwent LSA debranching using an aortoaxillary bypass. Indication for surgery was acute aortic dissection (AD, 54%), chronic AD (22%) and aortic aneurysm (24%). An 8-mm graft was used for the extra-anatomic bypass. The graft crossed the left hemithorax through the first intercostal space and was anastomosed at the proximal aorta after replacement during the cardiac reperfusion. Arch repair by FET was performed in zone 2 (96%) or more proximal (4%) after additional debranching. During the follow-up, 2.1 ± 1.8 years computed tomography (CT) examinations were performed.

Results: Thirty-day mortality was 12.7%. Permanent neurological complications were observed as stroke or paraplegia in 6 and 1%, respectively. No laryngeal nerve palsy occurred. During follow-up, the patency rate of the aortoaxillary bypass was 97.5%. Occlusion of the graft was documented in four patients. In two of them carotid-subclavian bypass was performed due to LSA-Steal syndrome. The other two patients were asymptomatic. Graft infection occurred in one patient. In this case, the graft was removed via left thoracotomy and the LSA was revascularized by carotid-subclavian bypass. Four patients underwent left thoracotomy for thoracoabdominal aorta replacement and the stentgrafted middescending aorta could be clamped without mobilization of the extra-anatomic graft.

Conclusion: Use of extra-anatomic left aortoaxillary bypass for LSA debranching facilitates the aortic arch repair by FET fixation in zone 2. The risk of graft occlusion or infection in midterm follow-up is low and can be overcome by carotid-subclavian bypass, if required.