S4773 Aorto-Esophageal Fistula as a Rare Cause of Upper Gastrointestinal Bleeding

Introduction: Upper gastrointestinal (GI) bleeding is a significant cause of morbidity and mortality in hospitalized patients, with a broad differential diagnosis. While common etiologies include peptic ulcer disease and varices, rare causes such as aorto-esophageal fistula (AEF) must be considered, especially given their high mortality. AEF, often presenting with massive bleeding, requires a high index of suspicion for timely diagnosis and intervention. We present a 77-year-old woman with upper GI bleeding secondary to AEF in the setting of an infected thoracic aortic endograft. Case Description/Methods: A 77-year-old woman with a remote history of Type A aortic dissection status post thoracic aortic endovascular repair presented with fever, chills, and melena. Labs revealed a hemoglobin of 5.4 g/dL. Computed tomography chest showed a gas-containing abscess in the medial aortic hemiarch and extraluminal contrast concerning for endoleak. Given her comorbidities, she was deemed to be a poor surgical candidate and was started on broad-spectrum antibiotics for presumed graft infection. Initial upper endoscopy showed normal esophageal mucosa and inflamed, ulcerated gastric mucosa without active bleeding. On hospital day 6, she developed new-onset atrial fibrillation and was started on intravenous heparin. Hours later, she experienced massive hematemesis. Repeat endoscopy revealed active bleeding in the upper esophagus with a large submucosal hematoma and overlying clot, consistent with an aorto-esophageal fistula likely due to erosion from a mycotic aneurysm. Given ongoing bleeding and poor prognosis, goals of care were transitioned to comfort-focused measures. Discussion: Aorto-esophageal fistula (AEF) is an exceptionally rare but life-threatening cause of upper gastrointestinal bleeding, accounting for less than 0.1% of all cases. It is most associated with thoracic aortic aneurysms, malignancy, trauma, or complications from thoracic endovascular aortic repair. Clinical presentations are often nonspecific, typically including hematemesis, fever, and epigastric pain. This can lead to frequent delays in diagnosis. computed tomography angiography is the imaging modality of choice, while endoscopy aids in excluding other etiologies and guiding management. Despite advances in endovascular techniques, AEF carries an estimated mortality rate of 60%-90%, even with intervention. Given its rarity but high mortality, clinicians must maintain a high index of suspicion in the appropriate clinical context to enable timely recognition and improve outcomes.