768. ENDOSCOPIC MANAGEMENT OF COMPLEX THORACIC AORTA ANEURYSMAL SAC AND ENDOGRAFT INFECTION ASSOCIATED WITH AORTOESOPHAGEAL FISTULA
Authors: Basu Pallavi , Ong Hock Soo , Tan Jeremy Tian Hui 
Published: September 2024

Abstract

Background
Aortoesophageal fistula (AEF) is a rare but life-threatening condition. Secondary AEF is a complex pathology occurring after thoracic aorta surgery with prosthetic graft, with an incidence of 1.6%. However, this is likely to rise with the increasing number of thoracic endovascular aortic repair (TEVAR) being performed. Management of secondary AEF is more challenging due to presence of adhesions in the pleural space, co-existing endograft infection and poor physiology of this group of patients. Definitive surgery carries high mortality rate and not all patients are suitable candidates. We review a case of secondary AEF with thoracic endograft infection managed non-operatively.

Methods
Our patient is a 70 years old man with a background of Stanford type A aortic dissection managed with ascending aorta and hemi-arch replacement with Dacron graft. Six years later, he had frozen elephant trunk reconstruction due to aneurysmal dilatation. Three months later, he underwent TEVAR for descending thoracic aorta aneurysm. Post-operation, he was diagnosed with Flavonifractor plautii bactaeremia secondary to infected aneurysmal sac and aortic stent graft and was initiated on antimicrobial therapy. During this time patient also developed recurrent episodes of haemoptysis. Bronchoscopy excluded an aortobronchial fistula and Oesophago-gastro-duodenoscopy (OGD) confirmed AEF at 25 cm from incisors.

Results
After discussion with a multidisciplinary team and patient, endoscopic management was chosen over surgery. Initial endoscopic closure of AEF with over-the-scope-clip appeared satisfactory but repeat OGD showed recurrence of new AEF which was partially closed with clips. Repeat imaging showed worsening mediastinal infection with larger gas-containing cavity. OGD was repeated with contrast demonstrating fistulous connection between the oesophagus and aneurysmal sac. A 7-French 4 cm double pigtail (DPT) stent was deployed into the sac under fluoroscopy to allow for trans-oesophageal drainage. Repeat imaging showed improvement in infection (Figure 1). Patient underwent endoscopic exchange of DPT stent 2 months after the initial insertion.

Conclusion
Definitive surgery for secondary AEF includes drainage of infection, explantation of infected endograft and aortic and oesophageal reconstruction. Oesophagectomy is preferred over primary repair of oesophageal defect. Not all patients will be suitable candidates for radical surgery and a non-operative approach may be required. Our patient likely has dense pleural and mediastinal adhesions from previous surgeries and thus, repeat surgery will be more challenging with increased risk of complications. However, if his mediastinal infection fails to resolve despite a period of DPT stent drainage, definitive surgery involving McKeown minimally invasive oesophagectomy with substernal gastric pull up would be required.
Figure 1: Image A shows a large cavity with air and coalescent locules (arrow) prior to insertion of DPT stent. Image B shows a collapsed cavity (arrow) after DPT stent insertion.