S2209 Primary Aortoduodenal Fistula in a Native Aorta Causing Brisk Upper GI Bleeding

Abstract

INTRODUCTION: Primary aortoduodenal fistula (ADF) is a rare cause of gastrointestinal bleeding and is difficult to diagnose. Computed tomographic angiography (CTA) can be used to detect primary ADF. Open surgery or endovascular aortic repair (EVAR) for ADF improves survival. CASE DESCRIPTION/METHODS: 73-year-old male with atherosclerotic, native, non-surgically altered, normal diameter aorta complicating ADF presented with massive GI bleeding. Initially at outside hospital and was evaluated for intermittent episodes of hematemesis and hematochezia for one month. Repeated endoscopy failed to identify a source of bleeding, but blood was seen within the colon. Nuclear scans and CTAs showed no sources of active bleed/fistulas. He was transferred to our facility for further evaluation. On admission, he was in shock with a significant drop in his Hgb. Repeat endoscopy revealed a non-bleeding ulcer with a large visible vessel in the 3rd portion of the duodenum (Figure 1). Given the location and size, was felt not to be amenable to endoscopic therapy. Patient bled overnight. Urgent CTA showed active intraluminal hemorrhage within the duodenum and proximal jejunum, and abnormal periaortic soft tissue concerning for ADF (Figure 2). The Patient was taken to the IR and was found to have an ADF. Vascular surgery was consulted intra-operatively and performed an EVAR with stent-graft of the infrarenal aorta. The patient’s GI bleeding resolved. DISCUSSION: Primary ADF is an abnormal communication between the infrarenal aorta and duodenum involving the 3rd part of the duodenum in 2/3rd of cases and the 4th part in 1/3rd of cases. Primary ADF is an extremely rare entity. There were 791 ADF cases reported between 1951 and 2010, including 253 cases of primary ADF and 491 cases of secondary ADF. Of the primary cases, all included the presence of AAA. Our case is a patient with brisk upper GI bleeding, without high suspicion of ADF due to his history of a native, nonenlarged, unaltered aorta. We believe the pathophysiology of this case was a weakened aortic wall and inflammation secondary to chronic atherosclerosis resulting in fistula formation to the duodenum. A timely and accurate diagnosis of primary ADF may be challenging due to insidious episodes of GI bleeding, which are frequently under-diagnosed until the occurrence of massive hemorrhage. Clinicians should keep a high index of awareness for primary ADF, especially in elderly patients with unknown etiology of brisk upper GI bleeding with or without a known AAA.Figure 1Figure 2