Diagnosis of Aortoenteric Fistulas with CT Angiography

Chicken Bone Ingestion Leads to Aortoesophageal Fistula With Catastrophic Bleeding

Aortoesophageal fistula (AEF) is an uncommon, but potentially fatal cause of upper gastrointestinal bleeding. Aortoesophageal fistulas caused by foreign body ingestion are rare but devastating. The classic clinical triad of AEF consists of mid-thoracic pain or dysphagia, a herald episode of hematemesis, followed by fatal exsanguination after a symptom-free period (Chiari's triad). Computed tomography angiography (CTA) is the preferred diagnostic tool for identifying AEF and is substantially more sensitive than upper endoscopy for detecting AEF. Endoscopy can detect AEF as it might show pulsatile blood, pulsatile mass, hematoma, or adherent blood clot in the esophagus, or a deep esophageal tear. However, endoscopy has a low sensitivity and may delay definitive treatment. Several management options for AEF have been suggested; however, the definitive treatment is surgery performed on the thoracic aorta and esophagus, including esophagectomy, surgical replacement of the thoracic aorta, thoracic endovascular aortic repair, or omental flap. We report a case of a 63-year-old man who presented with hematemesis 2 weeks after chicken bone ingestion.

Features of infective native aortic aneurysms on computed tomography

Background

Infective native aortic aneurysm (INAA) is a rare clinical diagnosis. The purpose of this study was to describe the CT findings of INAAs in detail.

Methods

This was a retrospective single-center study of INAA patients at a major referral hospital between 2005 and 2020. All images were reviewed according to a protocol consisting of aneurysm features, periaortic findings, and associated surrounding structures.

Results

One hundred and fourteen patients (mean age, 66 years [standard deviation, 11 years]; 91 men) with 132 aneurysms were included. The most common locations were infrarenal (50.8%), aortoiliac (15.2%), and juxtarenal (12.9%). The mean transaxial diameter was 6.2 cm. Most INAAs were saccular (87.9%) and multilobulated (91.7%). Calcified aortic plaque was present in 93.2% and within the aneurysm in 51.5%. INAA instability was classified as contained rupture (27.3%), impending rupture (26.5%), and free rupture (3.8%). Rapid expansion was demonstrated in 13 of 14 (92.9%) aneurysms with sequential CT studies. Periaortic inflammation was demonstrated as periaortic enhancement (94.7%), fat stranding (93.9%), soft-tissue mass (92.4%), and lymphadenopathy (62.1%). Surrounding involvement included psoas muscle (17.8%), spondylitis (11.4%), and perinephric region (2.8%). Twelve patients demonstrated thoracic and abdominal INAA complications: fistulas to the esophagus (20%), bronchus (16%), bowel (1.9%), and inferior vena cava (IVC) (0.9%).

Conclusion

The most common CT features of INAA were saccular aneurysm, multilobulation, and calcified plaques. The most frequent periaortic findings were enhancement, fat stranding, and soft-tissue mass. Surrounding involvement, including psoas muscle, IVC, gastrointestinal tract, and bronchi, was infrequent but may develop as critical INAA complications.

Periaortic air in native and post-operative aorta on computed tomography

Periaortic air can be seen in various conditions which can be a benign imaging finding or harbinger of a catastrophic event. The causes vary in native aorta and post-operative aorta. A radiologist has an important part in the management process of these patients, as the treatment varies from conservative to radical surgery based on the aetiology. The presence of periaortic air seen in the light of various clinical, laboratory and radiological findings can guide the radiologist towards a particular aetiology. Cross-sectional imaging, mainly computed tomography, is an indispensable tool in recognising ectopic periaortic air and to identify the associated findings and eventually make an accurate diagnosis. We present a pictorial review of various causes of the periaortic air in native and postoperative aorta, the salient features and management of the described conditions.

Aortic Fistulas: Pathophysiologic Features, Imaging Findings, and Diagnostic Pitfalls

Fistulas between the aorta and surrounding organs are extremely rare but can be fatal if they are not identified and treated promptly. Most of these fistulas are associated with a history of trauma or vascular intervention. However, spontaneous aortic fistulas (AoFs) can develop in patients with weakened vasculature, which can be due to advanced atherosclerotic disease, collagen-vascular disease, vasculitides, and/or hematogenous infections. The clinical features of AoFs are often nonspecific, with patients presenting with bleeding manifestations, back or abdominal pain, fever, and shock. Confirmation with invasive endoscopy is often impractical in the acute setting. Imaging plays an important role in the management of AoFs, and multiphasic multidetector CT angiography is the initial imaging examination of choice. Obvious signs of AoF include intravenous contrast material extravasation into the fistulizing hollow organ, tract visualization, and aortic graft migration into the adjacent structure. However, nonspecific indirect signs such as loss of fat planes and ectopic foci of gas are seen more commonly. These indirect signs can be confused with other entities such as infection and postoperative changes. Management may involve complex and staged surgical procedures, depending on the patient's clinical status, site of the fistula, presence of infection, and anticipated tissue friability. As endovascular interventions become more common, radiologists will need to have a high index of suspicion for this entity in patients who have a history of aneurysms, vascular repair, or trauma and present with bleeding. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ^©RSNA, 2021.

Concurrent Ilio-Enteric and Ilio-Vesical Fistula From Large Aorto-Iliac Aneurysm

Iliac artery aneurysms (IAA) are associated frequently with abdominal aortic (AAA) and other degenerative large-vessel aneurysms. Concurrent fistulization of the aortoiliac tree into the gastrointestinal tract (GIT) and bladder is exceptionally rare. We herewith report a unique case of concurrent ilio-enteric and ilio-vesical fistula arising from a large aorto-iliac aneurysm.

Case series of aortoenteric fistulas: a rare cause of gastrointestinal bleeding

BACKGROUND

Aortoenteric fistula (AEF) is a rare cause of gastrointestinal bleeding and is often misdiagnosed in clinical practice. Herein, a case series of AEFs are presented and the clinical characteristics, diagnosis, and management strategies are summarized.

METHODS

A retrospective analysis was performed on consecutive hospitalized patients with a final diagnosis of AEF at Beijing Friendship Hospital, Capital Medical University, between January 1, 2007 and March 31, 2020. The clinical data including diagnostic and management procedures as well as outcomes were collected and summarized.

RESULTS

A total of nine patients were included in this study, five with primary AEF and four with secondary AEF. Eight of the patients were male, and the median age was 63 years. The fistulas were located in both the small intestine and the colon. All patients presented with gastrointestinal bleeding and pain, followed by weight loss, anorexia, and fever. A typical abdominal triad was found in only two cases. Seven patients experienced complications with preoperative abdominal infections and sepsis, and multiple organ failure occurred in four of these patients. All patients were assessed by computed tomography and five underwent abdominal and/or iliac aorta angiography. Two of these patients showed contrast agent leakage from the abdominal aorta into the intestine. Two cases were diagnosed with AEF by endoscopy before the operation. Eight patients received surgery and six patients survived.

CONCLUSIONS

AEF is a rare cause of gastrointestinal bleeding that is associated with high mortality. Gastrointestinal bleeding and pain are the most common presentations. Timely diagnosis and multidisciplinary management are crucial to achieve a positive outcome.

Fatal secondary aortoduodenal fistula diagnosed with postmortem computed tomography angiography

Secondary aortoduodenal fistula (AEF), although less rare than its primary form, is an uncommon and frequently lethal cause of gastrointestinal (GI) bleeding. We report a case of fatal GI hemorrhage in a woman with a remote history of endovascular graft repair of an abdominal aortic aneurysm. Postmortem examination included computed tomography (PMCT) and CT angiography (PMCTA), which revealed air in the aorta, loss of the fat plane between the aorta and duodenum, and direct extravasation of contrast from the aorta into the duodenum. To our knowledge, this is the first published report of secondary AEF diagnosed by PMCT and confirmed with PMCTA. We propose a set of imaging criteria by which PMCTA can be used to supplant traditional anatomical dissection in the medicolegal investigation of deaths due to AEF.

Primary aortogastric fistula following Nissen fundoplication: A case report

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Aortogastric fistula is rare however often fatal.

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Diagnosis is frequently missed or delayed, and usually made intra-operatively or during autopsy.

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High index of suspicion and CTA are key to diagnosis.

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Endoscopy and catheter angiography are often non diagnostic.

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Surgical repair is the gold standard therapy, but endovascular repair is becoming the preferred initial treatment.

Introduction

Aortoenteric fistula (AEF) is a rare condition and consists of an abnormal communication between the aorta and the gastrointestinal (GI) tract. The duodenum is the most common location. Fistulas involving the stomach are very uncommon and account for only 2% of the cases. AEF typically results in rapid and fatal exsanguination as diagnosis is frequently missed or made too late (Bixby et al., 2018; Kougias et al., 2003; Lookman, 1959; Genc et al., 2000; Ong et al., 2019; Li et al., 2020).

Presentation of case

A 59 years old female with a history of Nissen fundoplication presented with lower gastrointestinal bleeding. Esophagogastroduodenoscopy (EGD) showed a large blood clot in the gastric fundus with no visible source of active bleeding. A mesenteric angiogram, performed for persistent gastro-intestinal bleeding and following two episodes of cardiac arrest, showed no evidence of active bleeding. The left gastric artery was prophylactically embolized. Persistent hemorrhage prompted an exploratory laparotomy followed by a left thoracotomy and confirmed the diagnosis of an aortogastric fistula (AGF). The patient expired intra-operatively.

Discussion

AGF is a very rare but often fatal condition (Busuttil and Goldstone, 2001). Computerized tomography angiography (CTA) can be a key to the diagnosis (Raman et al., 2012). EGD and catheter angiography have low sensitivity (Kuhara et al., 2015; Manduch et al., 2008). Definitive diagnosis is usually made during surgical exploration or autopsy (Wasvary et al., 1997). While open surgical repair is considered the gold standard therapy, endovascular therapy is becoming the preferred initial treatment option (Bixby et al., 2018).

Conclusion

AGF should be considered in the differential diagnosis of GI bleeding, especially in patients with massive hemorrhage where EGD and mesenteric angiography are not diagnostic.

Surgical Management for Aortoesophageal Fistula After Endovascular Aortic Repair

This case demonstrates successful surgical management of a 6-cm-long aortoesophageal fistula from an infected stent graft. A 69-year-old woman with a penetrating descending thoracic aortic ulcer underwent endovascular aortic repair. Two weeks later, she presented with nausea and melena, and she was found to have an infected stent graft on imaging. She underwent a two-stage procedure encompassing aortic arch debranching and extra-anatomic aortic bypass in stage 1, and stent graft resection, primary esophageal repair, intercostal and omental flap, and jejunostomy tube placement in stage 2. She was discharged 1 month later and is doing well 1.5 years after the operation.

Aortoenteric fistula secondary to an Inflammatory Abdominal Aortic Aneurysm

Primary aortoenteric fistulas are rare, with the annual incidence of such fistulas estimated to be 0.007 per million. The most common predisposing conditions for primary aortoenteric fistulas are atherosclerotic abdominal aortic aneurysms or penetrating atherosclerotic ulcers. We illustrate a rare case of an inflammatory aortic aneurysm causing a primary aortic fistula, with a direct fistulous jet from the aorta to the bowel with resultant catastrophic bleeding. In contrast to atherosclerotic aneurysms, most inflammatory aneurysms are symptomatic and show dense perianeurysmal fibrosis and periaortic wall thickening. A direct jet of contrast extravasation from the aorta into a bowel loop, while rarely seen, remains the most specific sign of a primary aorta-enteric fistula. A comprehensive literature review of the clinical presentation, imaging features, and differential diagnosis of a primary aortoenteric fistula are also discussed.

An Insidious Gastrointestinal Bleeding from Secondary Aortoduodenal Fistula Leading to Septic Shock

Insidious gastrointestinal bleeding from a secondary aortic fistula poses a significant diagnostic challenge. Failure to recognize it early on can lead to devastating outcomes. We describe a case of insidious gastrointestinal bleeding from a secondary aortic fistula in an elderly woman who presented with recurrent admissions for melanotic stools and eventually developed septic shock. Esophagogastroduodenoscopy did not reveal any obvious source of bleeding. The patient eventually had push endoscopy that revealed infected graft and a secondary aortoduodenal fistula. One should proceed with push enteroscopy in occult bleeding if the patient has a history of abdominal aortic aneurysm repair.

Aortoenteric fistula: a rare but critical cause of small bowel bleeding discovered on capsule endoscopy

A 78-year-old man attended for outpatient capsule endoscopy, to investigate a recent history of unexplained small bowel bleeding. His previous medical history included an abdominal aortic aneurysm repair 6 years ago. Soon after capsule ingestion, he experienced sudden onset abdominal pain and collapsed on hospital grounds. He was rapidly transferred to the emergency department as he was haemodynamically unstable, and a significant per rectum (PR) bleed was found on examination. The patient was quickly stabilised following fluid resuscitation. CT angiography was performed which did not show active bleeding. However, use of the real-time capsule viewer indicated a profuse active jejunal bleed originating from the aortic graft, suggestive of an aortoenteric fistula. The patient underwent emergency endovascular cuff placement, and subsequent endovascular abdominal aortic stent grafting, to good effect.

Aortic Bulge: A Possible Predictive Sign of Impending Aortoenteric Fistula

Purpose

The purpose of this study is to introduce the aortic bulge sign, a finding observed retrospectively on computed tomography prior to the acute presentation of aortoenteric fistula, and to determine its interobserver reliability.

Methods

Following research ethics board approval, all cases of aortoenteric fistula at our institution occurring from 2011–2015 were identified retrospectively. All previous computed tomography images of patients who eventually developed aortoenteric fistula were reviewed by a single observer for the presence of a potentially predictive finding of fistulization, the aortic bulge sign. These previous images were then combined with age and sex matched controls into a case bank. Eight radiology residents and staff were instructed in observing the aortic bulge sign. These observers then reviewed the case bank in a blinded analysis to determine the interobserver reliability of this finding.

Results

Fourteen cases of aortoenteric were identified. The average patient age was 70.71 years with a male-to-female ratio of 11:3. Eleven patients had previous computed tomography images available for review. With blinded analysis by multiple observers, the aortic bulge sign was identified with greater than 80% agreement in six of 11 cases (66.67%). Fleiss' kappa was calculated at k = 0.60 (95% confidence interval 0.50–0.69), corresponding to moderate-to-substantial interobserver agreement.

Conclusions

The aortic bulge sign has been retrospectively identified as a promising computed tomography finding of eventual aortoenteric fistula prior to acute presentation. Further study is required to determine the diagnostic value of this sign.

A case report of successful treatment of secondary aortoenteric fistula complicated with gastrointestinal bleeding and retroperitoneal abscess in an elderly patient

RATIONALE

The treatment of secondary aortoenteric fistula (SAEF) involves maintaining hemodynamic stability, infection control, revascularization, and surgical repair. Conventional open repair is associated with high mortality, whereas endovascular stent-graft repair is associated with recurrent infection or bleeding.

PATIENT CONCERNS

We report the case of an 85-year-old man with SAEF who presented with gastrointestinal bleeding and retroperitoneal abscess.

DIAGNOSES

He was misdiagnosed for 5 months. SAEF was eventually diagnosed by CT and gastroduodenoscopy.

INTERVENTIONS

The patient underwent hybrid open surgery: extraanatomic left axillofemoral bypass graft reconstruction, exploratory laparotomy, aortic stent graft excision, infrarenal abdominal aortic suture, left common iliac artery ligation, extensive surgical debridement, and retroperitoneal abscess resolution and drainage, along with duodenal defect repair and jejunal feeding tube placement.

OUTCOMES

He survived the complicated surgery and several life-threatening complications with multidisciplinary management. He has kept well for 15 months.

LESSONS

Elderly SAEF patients can undergo open repair when circumstances permit, but multidisciplinary management is crucial.

Primary Aortoduodenal Fistula: First you Should Suspect it

A 59 year-old patient was admitted with upper gastrointestinal bleeding. The clinical exam showed mild hypotension and blood samples revealed acute anemia (hemoglobin = 7.5 g/dl). Emergency computed tomography showed an infrarenal abdominal aortic aneurysm and extravasation of the arterial contrast material toward the digestive tract. The patient was transported to the operating room for emergency laparotomy, which showed an aortoduodenal fistula. After proximal and distal aortic vascular control, the two anatomical structures were dissected with duodenorrhaphy, patch repair of the aortic tear and omentum interposition. The postoperative recovery was uneventful, with discharge after 12 days.

Secondary aortoduodenal fistula and the unrecognised herald bleed

A 65-year-old man with history of aortobifemoral surgery 4 years ago was admitted to hospital after sudden abdominal pain. Initially misdiagnosed as renal colic, he was treated with analgesics, and while on observation he started with haematemesis, rapidly responding to volume infusion. Upper gastrointestinal endoscopy showed fresh blood in the stomach with no visible active bleeding. CT scan showed an important contrast extravasation from the aorta to the third duodenal portion, restarting haemodynamic instability and a cardiac arrest. Cardiopulmonary resuscitation (CPR) manoeuvres followed by intense fluid resuscitation and urgent laparotomy with a fast transabdominal supracoeliac aortic clamping was performed. After multiple blood and plasma unit transfusion and intravenous norepinephrine, two more cardiac arrests were recovered. Unfortunately, after aggressive management, the patient rapidly deteriorated and deceased on the table. Aortoduodenal fistula is a rare entity causing life-threatening bleeding. Its diagnosis requires high clinical suspicion and surgery offers the only hope for survival.

Management of aorto-esophageal fistula secondary after thoracic endovascular aortic repair: a review of literature

Aorto-esophageal fistula (AEF) is a rare and lethal entity, and the difficulty of making diagnosis of AEF is well-known. As promising results in the short-term effectiveness of thoracic endovascular aortic repair (TEVAR) promote its usage, the occurrence of AEF after TEVAR (post-TEVAR AEF) increases as one of the major complications. Therefore, we provide a review concerning the management strategy of post-TEVAR AEF. Although its representative symptom was reported as the triad of mid-thoracic pain and sentinel hematemesis followed by massive hematemesis, the symptom-free interval between sentinel hemorrhage and massive exsanguination is unpredictable. However, the physiological condition represents a surgical contraindication. Accordingly, early diagnosis is important, but either CT or esophago-gastro-duodenoscopy rarely depicts a typical image. The formation of post-TEVAR AEF might be associated with the infection of micro-organisms, which is uncontrollable with anti-biotic administration. The current first-line strategy is combination therapy as follows, (1) to control bleeding by TEVAR in the urgent phase, and (2) radical debridement and aortic/esophageal re-construction in the semi-urgent phase. In view of the high mortality and morbidity rate, it is proposed that the choice in treatment strategies might be affected by patient`s condition, size of the wall defects and the etiology of AEF. Practically, we should keep in mind the importance of making an early diagnosis and, once a suspicious symptom has occurred in a patient with a history of TEVAR, the existence of post-TEVAR AEF should be suspected. A prospective registry together with more developed technologies will be needed to establish a future strategy.

Atypical Aortoesophageal Fistula with Atypical and Delayed Presentation and Negative Imaging Studies

A 59-year-old man with past medical history of thoracic aortic aneurysm treated with thoracic endovascular aortic repair presented with melena for 2 weeks. Initial EGD did not reveal the source of bleeding and showed normal esophagus; abdominal arteriogram did not reveal a fistulous communication and initial CTA showed normal position of the aortic graft stent without endoleak. The sixth EGD revealed a submucosal tumor-like projection in the upper esophagus and stigmata of recent bleeding. Another thoracic endovascular aortic repair with stent was placed over the old graft for presumed aortoesophageal fistula. Poststent upper gastrointestinal series with contrast showed extravasation of the contrast from the esophagus and CTA showed fistulous tract between aorta and esophagus. The patient refused definitive surgical repair despite having infected aortic graft; jejunostomy tube was placed and life-long suppressive antibiotic treatment was given and the patient is doing well at 2-year follow-up.

Editor's Choice - Management of Secondary Aorto-enteric and Other Abdominal Arterio-enteric Fistulas: A Review and Pooled Data Analysis

OBJECTIVES

To compare management strategies for secondary abdominal arterio-enteric fistulas (AEFs).

METHODS

This study is a review and pooled data analysis. Medline and Scopus databases were searched for studies published between 1999 and 2015. Particular emphasis was given to short- and long-term outcomes in relation to AEF repair type.

RESULTS

Two hundred and sixteen publications were retrieved, reporting on 823 patients. In-hospital mortality was 30.7%. Open surgery had higher in-hospital mortality (246/725, 33.9%), than endovascular methods (7/98, 7.1%, p < .001, OR 6.7, 95% CI 3-14.7, including staged endovascular to open surgery, 0/13, 0%). In-hospital mortality after graft removal/extra-anatomical bypass grafting was 31.2% (66/226), graft removal/in situ repair 34% (137/403), primary closure of the arterial defect 62.5% (10/16), and for miscellaneous open procedures 41.3% (33/80), p = .019. Among the subgroups of in situ repair, homografts were associated with a higher mortality than impregnated prosthetic grafts (p = .047). There was no difference in recurrent AEF-free rates between open and endovascular procedures. Extra-anatomical bypass/graft removal and in situ repair had a lower AEF recurrence rate than primary closure and homografts. Late sepsis occurred more often after endovascular surgery (2-year rates 42% vs. 19% for open, p = .001). The early survival benefit of endovascular surgery was blunted during follow-up, although it remained significant (p < .001). Within the in situ repair group, impregnated prosthetic grafts were associated with the worst overall and AEF related mortality free rates and vein grafts with the best. No recurrence, sepsis, or mortality was reported following staged endograft placement to open repair after a mean follow-up of 16.8 months (p = .18, p = .22, and p = .006, respectively, compared with patients in other groups).

CONCLUSIONS

Endovascular surgery, where appropriate, is associated with better early survival than open surgery for secondary AEFs. Most of this benefit is lost during long-term follow-up, implying that a staged approach with early conversion to in situ vein grafting may achieve the best results in selected patients.

Unstable abdominal aortic aneurysms: a review of MDCT imaging features

Abdominal aortic aneurysms are commonly encountered during abdominal CT imaging, and size-based parameters for surgical or endovascular repair are well established. Aneurysms greater than 5 cm in diameter are recognized as representing an increased rupture risk and meriting intervention. Increasingly, additional interest has been generated in recognizing imaging features which may herald instability and portend a higher chance for potentially catastrophic rupture. This article will review and illustrate such signs, including hyperattenuation of mural thrombus, rapid expansion, low thrombus to lumen ratio, intimal calcification disruption, posterior mural draping, and saccular outpouching. Other features of complicated abdominal aneurysms including perianeurysmal inflammation, aortocaval and aortoenteric fistula formation will also be addressed. Heightened awareness of these features and their prognostic implications, as well as timely communication with the clinical service, is critical for the interpreting radiologist.

Critical gastrointestinal bleed due to secondary aortoenteric fistula

Secondary aortoenteric fistula (SAEF) is a rare yet lethal cause of gastrointestinal bleeding and occurs as a complication of an abdominal aortic aneurysm repair. Clinical presentation may vary from herald bleeding to overt sepsis and requires high index of suspicion and clinical judgment to establish diagnosis. Initial diagnostic tests may include computerized tomography scan and esophagogastroduodenoscopy. Each test has variable sensitivity and specificity. Maintaining the hemodynamic status, control of bleeding, removal of the infected graft, and infection control may improve clinical outcomes. This review entails the updated literature on diagnosis and management of SAEF. A literature search was conducted for articles published in English, on PubMed and Scopus using the following search terms: secondary, aortoenteric, aorto-enteric, aortoduodenal, aorto-duodenal, aortoesophageal, and aorto-esophageal. A combination of MeSH terms and Boolean operators were used to device search strategy. In addition, a bibliography of clinically relevant articles was searched to find additional articles (Appendix A). The aim of this review is to provide a comprehensive update on the diagnosis, management, and prognosis of SAEF.

Diagnosis of gastrointestinal bleeding: A practical guide for clinicians

Gastrointestinal bleeding is a common problem encountered in the emergency department and in the primary care setting. Acute or overt gastrointestinal bleeding is visible in the form of hematemesis, melena or hematochezia. Chronic or occult gastrointestinal bleeding is not apparent to the patient and usually presents as positive fecal occult blood or iron deficiency anemia. Obscure gastrointestinal bleeding is recurrent bleeding when the source remains unidentified after upper endoscopy and colonoscopic evaluation and is usually from the small intestine. Accurate clinical diagnosis is crucial and guides definitive investigations and interventions. This review summarizes the overall diagnostic approach to gastrointestinal bleeding and provides a practical guide for clinicians.

Aortoenteric fistula as a complication of open reconstruction and endovascular repair of abdominal aorta

The paper intends to present a review of imaging characteristics of secondary aortoenteric fistula (AEF). Mechanical injury, infection, and adherence of a bowel segment to the aorta or aortic graft are major etiologic factors of AEF after open aortic repair. The pathogenesis of AEF formation after endovascular abdominal aortic repair is related to mechanical failure of the stent-graft, to stent graft infection, and to persistent pressurization of the aneurysmal sac. The major clinical manifestations of AEF comprise haematemesis, melaena, abdominal pain, sepsis, and fever. CT is the initial diagnostic modality of choice in a stable patient. However, the majority of reported CT appearances are not specific. In case of equivocal CT scans and clinical suspicion of AEF, scintigraphy, (67)Ga citrate scans or (18)F-FDG PET/CT is useful. Diagnostic accuracy of endoscopy in evaluation of AEF is low; nevertheless it allows to evaluate other than AEF etiologies of gastrointestinal bleeding. Without adequate therapy, AEF is lethal. Conventional surgical treatment is associated with high morbidity and mortality. The endovascular repair may be an option in hemodynamically unstable and high-risk surgical patients. We also illustrate an example of a secondary AEF with highly specific albeit rare radiologic picture from our institution.

Graft-appendiceal fistula treated with a rifampicin-silver in-situ graft

BACKGROUND

We report a 52-year-old male presenting with a graft-appendiceal fistula four years after placement of an aorto-bifemoral Dacron prosthesis.

CASE REPORT

After appendectomy and total graft removal, the patient was treated with an in-situ repair using a rifampicin-silver graft. This kind of repair has only been reported in an animal study.

RESULTS

This infected aortic graft was treated successfully with a rifampicin-silver graft with a follow-up of 15 months without complications.

CONCLUSION

In-situ repair of a graft-appendiceal fistula with a rifampicin-silver graft seems a promising strategy. The long-term outcome needs to be studied.

Nontraumatic acute aortic emergencies: Part 2, Pre- and postsurgical complications related to aortic aneurysm in the emergency clinical setting

OBJECTIVE

The aim of this article is to illustrate the imaging findings and spectrum of disease entities affecting the aorta. The clinical presentation and assessment of acute aortic pathology can be elusive or deceptive, making the diagnosis challenging. The widespread availability of advanced cross-sectional imaging technology in the emergency setting puts the radiologist at the forefront of accurate and timely diagnosis.

CONCLUSION

Cross-sectional imaging plays a pivotal role in the diagnosis and delineation of aortic pathology. Awareness of the imaging findings and complications can help in swift and accurate diagnosis.

Aorto-enteric fistulas: a physiopathological approach and computed tomography diagnosis

Infection of an abdominal aortic prosthesis with an enteroprosthetic fistula is a very serious, life-threatening complication, leading sometimes to severe functional consequences, the most serious being amputation. Since the symptoms, if there are any, are often rather non-specific, diagnosis is frequently difficult and has always to be based on a whole series of justifications. Early diagnosis is essential and this fistula should be the first possibility considered in a patient with an abdominal aortic prosthesis who is presenting rectorrhagia or melaena (even if only to a slight degree), sepsis and/or abdominal pain. Although rare, the clinical existence of hypertrophic osteoarthropathy may assist diagnosis. A CT scan is the examination of choice, the criteria providing evidence of a fistula being the presence of gaseous images in a periprosthetic fluid collection, thickening and/or retraction of the intestinal walls in contact, the existence of a false aneurysm, and finally, very rarely, extravasation of contrast agent into the intestinal lumen. The differential diagnoses that may mimic a fistula need to be well known, and can include retroperitoneal fibrosis, an infectious aneurysm, inflammatory or infectious aortitis, and above all, a 'simple' prosthesis infection without fistulisation.

Prosthetic vascular graft infection imaging

PURPOSE

We are reporting our experience with imaging of vascular graft infections using computed tomography angiography (CTA), white blood cell (WBC) scintigraphy and software-based fusion imaging.

MATERIAL AND METHODS

Institutional review board approval was obtained. We performed a retrospective review of patients who had clinical signs and symptoms of vascular graft infection in whom both WBC single photon emission computed tomography (SPECT) and CTA was performed between 2005 and 2010. We performed fusion imaging with available data using software coregistration technique and analyzed outcome of the patients.

RESULTS

We had 20 patients; 11 had grafts of the aorta, five had peripheral vascular grafts, three had aortic and peripheral vascular grafts, and one had a thoracic aortic graft. WBC imaging was positive in 10 patients, negative in six patients and indeterminate in 4 patients. CTA was positive in six patients, negative in four patients and indeterminate in 10 patients. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value (NPV) for WBC, CTA and WBC SPECT/CTA fusion were 75/100/80/100/50%, 88/50/80/88/50% and 94/50/85/88/67% respectively.

CONCLUSION

The use of CTA, WBC scintigraphy, and image co-registration influenced the diagnostic confidence of graft infection and the outcome of the patients. Software-based fusion imaging of both modalities resulted in improved sensitivity, accuracy, and NPV.

Aortoenteric fistulae: present-day management

An aortoenteric fistula (AEF) is a communication between the aorta and an adjacent loop of the bowel. The three most useful diagnostic modalities for detecting AEF are abdominal computed tomography scan with intravenous contrast, esophagogastroduodenoscopy, and arteriography. The treatment of AEFs has improved in recent years, but despite the multiple surgical techniques reported, many of the patients do not survive or are left debilitated after treatment. Endovascular repair is an efficient and safe method to stabilize patients with life-threatening AEFs. The aim of this study is to provide a comprehensive and synthetic review of the latest advantages on the diagnosis and management of primary and secondary AEF.

Aortoenteric fistulas: CT features and potential mimics

Prompt diagnosis of aortoenteric fistulas is imperative for patient survival. The clinical signs of aortoenteric fistula include hematemesis, melena, sepsis, and abdominal pain, but the condition also may be clinically occult. Because clinical signs may not be present or may not be sufficiently specific, imaging is most often necessary to achieve an accurate diagnosis. Although no single imaging modality demonstrates the condition with sufficient sensitivity and specificity, computed tomography (CT), owing to its widespread availability and high efficiency, has become the imaging modality of choice for evaluations in the emergency setting. CT has widely variable sensitivity (40%-90%) and specificity (33%-100%) for the diagnosis of aortoenteric fistulas. To use this modality effectively for the initial diagnostic examination, radiologists must be familiar with the spectrum of CT appearances. Mimics of aortoenteric fistulas include retroperitoneal fibrosis, infected aortic aneurysm, infectious aortitis, and perigraft infection without fistulization. Differentiation is aided by the observation of ectopic gas, loss of the normal fat plane, extravasation of aortic contrast material into the enteric lumen, or leakage of enteric contrast material into the paraprosthetic space; these features are highly suggestive of aortoenteric fistula in a patient with bleeding in the gastrointestinal tract.

Secondary iliac-enteric fistula to the sigmoid colon complicated with entero-grafto-cutaneous fistula

We report the case of a 67-year-old man who was admitted to our department with acute rectal bleeding. The patient had had previous aortoiliac surgery with the utilization of an aortobifemoral vascular prosthesis. Diagnosis of aortoenteric fistula was made between the distal suture line of the right graft leg and the sigmoid colon. This fistula had an enterocutaneous component. After exploratory laparotomy, primary resection of the sigmoid colon, exstirpation of the enterocutaneous fistula, excision of the right graft leg and extraanatomical crossover bypass were successfully performed. This study reports a rare type of aorto/ilac-enteric fistula to the left colon complicated with an entero-grafto-cutaneous component and describes an unusual and successful surgical treatment method.