Aorto-enteric fistula following endovascular repair of abdominal aortic aneurysm

Aortoenteric Fistulas Following Endovascular Aortic Aneurysm Repair: A Review

BackgroundSecondary aortoenteric fistulas (SAEF) following endovascular aortic repair (EVAR) is an extremely rare event but life threatening. Our review offers comprehensive knowledge on pathophysiology, clinical presentation, diagnosis, and treatment options.AimTo summarize the current literature regarding pathophysiology, clinical, diagnostic and therapeutic approach of aortoenteric fistulas secondary to EVAR.MethodsWe performed a literature search in Pubmed/MEDLINE to identify the literature published about SAEF after EVAR. Cases were summarized in a table and prevalences. Other relevant literature was included in the results sections.ResultsA total of 35 reports (single cases and small series) with 45 patients were included. SAEF after EVAR can result from infection, inflammation, or mechanical factors. Clinical presentation is often non-specific, ranging from a gastrointestinal herald bleed to hemorrhagic shock, or malaise and general infection-related symptoms. Cross-sectional imaging plays a critical role in diagnosing SAEF. The treatment approach involves a multidisciplinary team approach and requires broad-spectrum intravenous antibiotics, endovascular intervention for urgent hemorrhage control, and open surgical intervention for definitive repair. Long-term antimicrobial therapy is essential to avoid reinfection.ConclusionsSAEF following EVAR represents a complex, life-threatening condition with limited evidence-based management strategies. Given the growing prevalence of endovascular procedures, comprehensive knowledge of SAEF is crucial for all health care providers to improve early diagnosis and outcomes.

Burden of Candida-related vascular graft infection: a nested-case control study

PURPOSE

We aimed to assess risk factors of candida-related Vascular Graft Infections (VGIs).

METHODS

We did a case-control study (1:4) matched by age and year of infection, nested in a cohort of patient with a history of VGIs. Cases were defined by a positive culture for Candida spp. in biological samples and controls were defined by a positive culture for bacterial strains only in biological samples. Risk factors for Candida-related VGIs were investigated using multivariate logistic regression. Mortality were compared using survival analysis.

RESULTS

16 Candida-related VGIs were matched to 64 bacterial-related VGIs. The two groups were comparable regarding medical history and clinical presentation. Candida-related VGIs were associated with bacterial strains in 88% (14/16). Gas/fluid-containing collection on abdominal CT scan and the presence of an aortic endoprosthesis were risk factors for Candida spp.-related VGIs [RRa 10.43 [1.81-60.21] p = 0.009 RRa and 6.46 [1.17-35.73] p = 0.03, respectively]. Candida-related VGIs were associated with a higher mortality when compared to bacterial-related VGIs (p = 0.002).

CONCLUSIONS

Candida-related VGIs are severe. Early markers of Candida spp. infection are needed to improve their outcome. The suspicion of aortic endoprosthesis infection may necessitate probabilistic treatment with antifungal agents.

Digestive hemorrhage and fever as a result of a double secondary aortoenteric fistula following the repair of a juxtarenal abdominal aortic aneurysm and an infection of the aortobifemoral bypass graft: a case report

A double secondary aortoenteric fistula (AEF) occurs in a patient who has had significant aortic surgery and is characterized by a direct connection between the gastrointestinal (GI) tract and the aorta at two separate sites.

IMPORTANCE

During aortoc reconstructive surgery, the patient may present with a variety of unusual complaints, including fever and GI bleeding. These symptoms are indicative of problems, including the development of an aortoentric fistula, particularly when there is a double secondary fistula.

CASE PRESENTATION

The patient was admitted to the hospital due to hematemesis, melena, and high-grade fever after undergoing synthetic grafting aortobifemoral bypass (anatomical reconstruction) and partial resection of the juxtarenal abdominal aortic aneurysm. Pus discharge and a double aortoenteric fistula in unusual sites such as the second-third portion of the duodenum and caecum are visible in upper GI endoscopy and computed tomography angiography. The patient underwent a two-stage open surgery, the first stage involving aortic limb graft exclusion and extra anatomical reconstruction, and the second stage involving graft removal, fistula management, and bowel repair. Then the patient spent a few days in the surgical intensive care unit before being discharged.

CLINICAL DISCUSSION

Primary and secondary AEF are the two categories of AEF. In patients who underwent aortic reconstruction surgery, the frequency of secondary AEF ranges from 0.36 to 1.6%. Due to the 8:1 injury ratio in the secondery AEF, men suffer more injuries than women.There are two types of fistula depending on whether or not the suture line is involved. The first form is graft enteric erosion, which excludes the suture line, while the second type is entric graft fistula, where the suture line is included. Most common site fistula is third and fourth part of duodenum and least common site is fistula formation in large bowel.

CONCLUSIONS

An uncommon complication is double secondary AEF following aortic reconstruction surgery. Since one of the most significant presentations an AEF patient can present with is major GI bleeding and sepsis, A delay in seeking immediate medical treatment could result in the patient's death. It should be emphasized that one of the mechanisms for AEF formation and a frequent cause of sepsis in patients is recurrent aortic graft infection following aortic reconstruction surgery.

Aortoenteric Fistula after Endovascular Aneurysm Repair

Aortoenteric fistula is a rare complication following endovascular abdominal aortic aneurysm repair. However, there is a significant morbidity and mortality associated with this complication. Patients can present with gastrointestinal hemorrhage, fever, or nonspecific features of chronic infection. Extra anatomic bypass with complete graft explanation is the standard management.

Aortoduodenal fistulas after endovascular abdominal aortic aneurysm repair and open aortic repair

OBJECTIVE

In the present study, we have reported and compared aortoduodenal fistulas (ADFs) after endovascular abdominal aortic aneurysm repair (EVAR) vs after open aortic repair (OAR).

METHODS

We retrospectively analyzed the data from patients treated for ADFs from January 2015 to May 2020 in our hospital. The clinical data, diagnostic procedures, and surgical options were evaluated. The primary endpoints of the present study were 30-day and 1-year mortality. The secondary endpoints were major postoperative complications.

RESULTS

A total of 24 patients (20 men; median age, 69 years; range, 53-82 years) were admitted with ADFs after EVAR (n = 9) or OAR (n = 15). These patients accounted for ∼4.3% of all abdominal aortic aneurysm repairs in our hospital. The median interval from the initial aortic repair and the diagnosis of ADF was 68 months (range, 6-83 months) for the ADF-EVAR group and 80 months (range, 1-479 months) for the ADF-OAR group. Three patients in the ADF-EVAR group had refused surgical treatment owing to their high surgical risk. One patient in the ADF-OAR group had undergone removal of the aortic prosthesis without replacement. Of the remaining 20 patients, 12 (ADF-EVAR group, n = 4; ADF-OAR group, n = 8) had undergone in situ replacement of the aorta and 8 (ADF-EVAR group, n = 2; ADF-OAR group, n = 6) had undergone extra-anatomic reconstruction with aortic ligation. After a mean follow-up of 26 months, no patient had experienced early limb loss. However, one case of rupture of the venous graft (ADF-EVAR), one case of aortic stump blowout (ADF-OAR), and one case of a ureteroarterial fistula with a homograft (ADF-OAR) had occurred. Overall, the incidence of postoperative complications was significantly greater after ADF-OAR (93% vs 33%; P = .036). The most frequent bacteria involved in the blood cultures were Escherichia coli (25% of patients), and Candida spp. (61%) were the predominant pathogens found on intra-abdominal smears. The in-hospital mortality rates for the ADF-EVAR and ADF-OAR group were 22% and 13%, respectively. The corresponding 1 -year mortality rates were 22% and 33%.

CONCLUSIONS

Patients with ADFs after EVAR or OAR have limited overall survival. In addition to the similar therapeutic approaches, we found no significant differences in postoperative mortality between these two uncommon pathologic entities. In our study, the overall postoperative morbidity seemed greater for the ADF-OAR group.

Customized stent-grafts for endovascular aneurysm repair with challenging necks: A numerical proof of concept

Endovascular aortic repair (EVAR) is a challenging intervention whose long-term success strongly depends on the appropriate stent-graft (SG) selection and sizing. Most off-the-shelf SGs are straight and cylindrical. Especially in challenging vessel morphologies, the morphology of off-the-shelf SGs is not able to meet the patient-specific demands. Advanced manufacturing technologies facilitate the development of highly customized SGs. Customized SGs that have the same morphology as the luminal vessel surface could considerably improve the quality of the EVAR outcome with reduced likelihoods of EVAR related complications such as endoleaks type I and SG migration. In this contribution, we use an in silico EVAR methodology that approximates the deployed state of the elastically deformable SG in a hyperelastic, anisotropic vessel. The in silico EVAR results of off-the-shelf SGs and customized SGs are compared qualitatively and quantitatively in terms of mechanical and geometrical parameters such as stent stresses, contact tractions, SG fixation forces and the SG-vessel attachment. In a numerical proof of concept, eight different vessel morphologies, such as a conical vessel, a barrel shaped vessel and a curved vessel, are used to demonstrate the added value of customized SGs compared to off-the-shelf SGs. The numerical investigation has shown large benefits of the highly customized SGs compared to off-the-shelf SGs with respect to a better SG-vessel attachment and a considerable increase in SG fixation forces of up to 50% which indicate decreased likelihoods of EVAR related complications. Hence, this numerical proof of concept motivates further research and development of highly customized SGs for the use in challenging vessel morphologies.

In silico study of vessel and stent-graft parameters on the potential success of endovascular aneurysm repair

The variety of stent-graft (SG) design variables (eg, SG type and degree of SG oversizing) and the complexity of decision making whether a patient is suitable for endovascular aneurysm repair (EVAR) raise the need for the development of predictive tools to assist clinicians in the preinterventional planning phase. Recently, some in silico EVAR methods have been developed to predict the deployed SG configuration. However, only few studies investigated how to assess the in silico EVAR outcome with respect to EVAR complication likelihoods (eg, endoleaks and SG migration). Based on a large literature study, in this contribution, 20 mechanical and geometrical parameters (eg, SG drag force and SG fixation force) are defined to evaluate the quality of the in silico EVAR outcome. For a cohort of n = 146 realizations of parameterized vessel and SG geometries, the in silico EVAR results are studied with respect to these mechanical and geometrical parameters. All degrees of SG oversizing in the range between 5% and 40% are investigated continuously by a computationally efficient parameter continuation approach. The in silico investigations have shown that the mechanical and geometrical parameters are able to indicate candidates at high risk of postinterventional complications. Hence, this study provides the basis for the development of a simulation-based metric to assess the potential success of EVAR based on engineering parameters.

Secondary Aorto-enteric Fistula and Type II Endoleak Five Years after Endovascular Abdominal Aortic Aneurysm Repair

Introduction

Secondary aorto-enteric fistula (AEF) after endovascular abdominal aortic aneurysm repair (EVAR) is a rare but potentially fatal disease. The aetiology and mechanisms are unclear. This study presents a patient who developed secondary AEF and type II endoleak five years after EVAR.

Case

A 73 year old man underwent successful EVAR with a bifurcated aortic stent graft for a 5.5 cm infrarenal abdominal aortic aneurysm. The aneurysm sac showed no change in size for three years, then shrank 20 mm to 3.5 cm by five years. After five years and eight months, the patient presented with fever and back pain. Enhanced CT demonstrated enlargement of the aneurysm sac, type II endoleak from the third and fourth right lumbar arteries, and air around the stent graft. An emergency operation was performed. The infected stent graft was removed by pushing up the stent graft to release the hooks from the wall of the aorta. A small fistula resembling a fish mouth measuring 1×1 cm was observed in the third part of the duodenum. The fistula was closed by direct suture, and in situ reconstruction was performed with an 18×9 mm standard polyethylene terephthalate graft. Culture of the explanted stent graft grew enterobacter. Intravenous antibiotic therapy was continued for six weeks and was stopped after confirming no recurrence of infection with computed tomography and laboratory testing. Two years later, there has been no recurrence of infection.

Conclusion

Long term surveillance is critical because AEF can occur even after initially successful EVAR.

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Secondary aorto-enteric fistula post endovascular abdominal aortic aneurysm repair can occur in the late phase of follow up.

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Staged omentopexy may be beneficial for prevention of recurrent infection.

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Type II endoleak can affect the development of secondary aorto-enteric fistula.

Secondary aortoenteric fistula possibly associated with continuous physical stimulation: a case report and review of the literature

BACKGROUND

Secondary aortoenteric fistula is a rare but fatal complication after reconstructive surgery for an aortic aneurysm characterized by abdominal pain, fever, hematochezia, and hematemesis, and the mortality rate is high. It has been suggested that it arises due to either continuous physical stimulation or prosthesis infection during primary surgery. We describe an aortoenteric fistula following reconstructive surgery for an abdominal aortic aneurysm together with postmortem pathological findings.

CASE PRESENTATION

A 59-year-old Japanese man who had undergone reconstructive surgery for an abdominal aortic aneurysm 20 months earlier presented with the chief complaint of hematochezia and malaise. Esophagogastroduodenoscopy and total colonoscopy revealed only colon diverticula with no bleeding. Contrast-enhanced computed tomography revealed gas within the aneurysm sac and adhesion between the replaced aortic graft and intestinal tract, suggesting a graft infection. After 18 days of antibiotic treatment, he suddenly went into a state of shock, with massive fresh bloody stool and hematemesis, followed by cardiac arrest. An autopsy revealed communication between the artery and the ileum through an ulcerative fistula at the suture line between the left aortic graft branch and the left common iliac artery. Pathological analysis revealed tight adherence between the arterial and intestinal walls, but no marked sign of infection around the fistula, suggesting that the fistula had arisen due to physical stimuli.

CONCLUSIONS

Pathological analysis suggested that the present secondary aortoenteric fistula arose due to physical stimuli. This reaffirms the importance of keeping reconstructed aortas isolated from the intestine after abdominal aortic aneurysm surgery.

Aortoenteric Fistula: A Late Complication of Endovascular Repair of an Inflammatory Abdominal Aortic Aneurysm

Endovascular repair provides a reasonable alternative to open repair for the treatment of abdominal aortic aneurysms in select cases. Although the endovascular approach may be preferable for inflammatory aneurysms, aggressive surveillance is needed to monitor for long-term complications. A 61-year-old man underwent endovascular exclusion of a symptomatic inflammatory abdominal aortic aneurysm with an AneuRx bifurcated aortic prosthesis. He presented with gastrointestinal bleeding 51/2 months later and was found to have an aortoenteric fistula involving the third portion of the duodenum. The aneurysm had expanded significantly at the proximal neck. The patient underwent successful removal of the device, aortic ligation, and extraanatomic bypass. Aortoenteric fistula is a rare but now established complication of endovascular aneurysm repair. The pathophysiology in these cases remains unclear. The presence of inflammation and endoleak may predispose to further aneurysmal degeneration.

Endovascular Graft Infection: Preliminary Results of an International Enquiry

Purpose:

To investigate the frequency of aortoiliac endovascular graft infections and seek the main factors influencing their development.

Methods:

To augment personal experience (1 case), a questionnaire was sent to 40 international centers of vascular and endovascular surgery. The literature was also reviewed to collect data on infections developing in endovascular grafts.

Results:

The survey (85% response rate) and literature review identified 62 cases of infected endovascular grafts (0.4% frequency of endograft infection). In 22 (35%) patients, the infection manifested initially with vague symptoms only, but 41 (65%) patients eventually presented with abdominal abscess, groin fistula, and septic embolization. Common bacteria, such as Staphylococcus aureus, were identified as the cause of most infections (54.5%). The majority (49, 79%) of the 62 patients were treated surgically; 11 (17.7%) patients received conservative therapy (no therapeutic data in 2 patients). Overall mortality was 27.4% (17/62), and operative mortality was 16.3% (8/49). Conservative treatment led to a mortality rate of 36.4% (4/11). The mean follow-up for all patients was 47.8 weeks. Possible factors influencing the development of an infection were secondary adjunctive procedures, immunosuppression, treatment of false aneurysms, and infected central lines.

Conclusions:

Infected endovascular grafts are an urgent problem that has been heretofore underestimated and will probably increase as follow-up lengthens. New techniques should be sought to expedite the diagnosis, and an international registry should be set up to provide validated data.

Aortoduodenal Fistula after Abdominal Aortic Stent Graft Presenting with Extremity Abscesses

Aortoenteric fistula (AEF) has been described after endovascular stent graft repair of abdominal aortic aneurysms (EVAR). AEF after EVAR has been associated with aneurysm growth, endoleak, migration, and aortic inflammation. We report a patient with an AEF presenting 2 years after EVAR with two abscesses in the right leg. A computed tomographic scan showed a gas-filled thrombus lining the right limb of his graft. At conversion, no endoleak, device migration, or residual aneurysm sac was found. AEF can occur after endoluminal stent graft (ELG) in the absence of aneurysm growth, endoleak, migration, or inflammation. AEF can cause ELG infection and extremity infection.

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.

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.

Prosthetic stent graft infection after endovascular abdominal aortic aneurysm repair

OBJECTIVE

The purpose of this report is to discuss the incidence, diagnosis, and management of stent graft infections after endovascular aneurysm repair (EVAR).

METHODS

Data were collected from the hospital database and medical case notes for all patients with infected endografts after elective or emergency EVAR for abdominal aortic aneurysm (AAA) during the last 8 years in two university teaching hospitals in Northern Ireland. The data included the patient's age, gender, presentation of sepsis, treatment offered, and the ultimate outcome. The diagnosis of graft-related sepsis was established by a combination of investigations including inflammatory markers, labelled white cell scan, computed tomography (CT) scan, microbiology cultures, and postmortem examination.

RESULTS

Graft-related septic complications occurred in six of 509 patients, including 433 elective repairs and 76 emergency endografts for ruptured AAA. Two patients presented with left psoas abscess and were treated successfully with extra-anatomic bypass and removal of the infected stent graft. Two more patients presented with infected graft without other evidence of intra-abdominal sepsis: one underwent successful removal of the infected prosthesis with extra-anatomical bypass, and the other was treated conservatively and died of progressively worsening sepsis. The fifth patient presented with unexplained fever and died suddenly, with a postmortem diagnosis of aortoenteric fistula and ruptured aneurysm. The last patient presented with an aortoenteric fistula, was treated conservatively in view of concurrent myelodysplasia, and died of possible aneurysm rupture.

CONCLUSION

This report emphasizes the need for continued awareness of potential graft-related septic complications in patients undergoing EVAR of AAA. Attention to detail with regard to sterility and antibiotic prophylaxis during stent grafting and during any secondary interventions is vital in reducing the risk of infection. In addition, early recognition and prompt treatment are essential for a successful outcome.

Aortoduodenal fistula 5 years after endovascular abdominal aortic aneurysm repair with the Ancure stent graft

We report a case of aortoduodenal fistula 5 years after uncomplicated endovascular abdominal aortic aneurysm repair. The diagnosis was confirmed by abdominal computed tomography scan and esophagogastroduodenoscopy. The patient was successfully treated with primary duodenal repair, removal of the infected graft, in situ placement of a bifurcated graft, and omental interposition. Review of the literature identifies this as one of very few documented aortoduodenal fistulas after endovascular aneurysm repair. Fistulization occurred despite accurate stent graft placement without migration, endoleak, or aortic sac size enlargement on annual postoperative imaging studies.

Aortoenteric fistula as a late complication of thrombolysis and bare metal stenting for perioperative occlusion of aortofemoral bypass

We previously described the case of a 47-year-old man who experienced perioperative graft occlusion after infrarenal aortic endarterectomy and aortobifemoral expanded polytetrafluoroethylene bypass graft for occlusive disease. The patient was treated with local graft thrombolysis and stenting of an intimal flap at the level of the endarterectomized aorta next to the aortic anastomosis. An urgent laparotomy performed 6 years later showed aortic wall perforation by the stent with a large aortoenteric fistula. Surgical treatment included removal of the stent and the aortobifemoral graft, bowel repair, and extra-anatomic lower-limb revascularization by axillofemoral and cross-femoral bypass grafting. The patient was discharged 12 days later with no early complications. Although local thrombolysis and stenting may be a technically feasible technique instead of reoperation in early aortofemoral graft thrombosis, long-term results of this procedure may be affected by perigraft hematoma due to perioperative thrombolysis, increased risk of infection due to the prolonged intragraft cannulation, and risk of stent-related aortic injury, especially if an endarterectomy has been performed. All these issues may increase the risk of late aortoenteric fistula. More experience with hybrid, open/endovascular procedures, and more contemporary stent-based devices is needed to assess the efficacy and safety of this alternative treatment.

Cholangitis after coil embolization of an iatrogenic hepatic artery pseudoaneurysm: an unusual case report

Pseudoaneurysm involving the hepatic arterial system is a recognized complication of biliary surgery. The standard nonsurgical treatment is coil embolization. We present a case of a patient who underwent coil embolization of a pseudoaneurysm and subsequently presented with ascending cholangitis due to migration of coils into the common bile duct.

Late Infection of an Endovascular Stent Graft with Septic Embolization, Colonic Perforation, and Aortoduodenal Fistula

We report on a 52-year-old male who developed late stent graft infection resulting in infective aneurysm formation with systemic septic embolization and aortoduodenal fistulation 9 months following endoluminal repair of an abdominal aortic aneurysm. Although endoluminal stent graft infection and erosion into surrounding viscera is rare, we highlight the need for awareness of this potentially catastrophic complication.

Computed Tomography and Ultrasound in Follow-up of Patients after Endovascular Repair of Abdominal Aortic Aneurysm

The purpose of this study was to compare our experience with duplex ultrasonography (US) and computed tomography (CT) for the routine follow-up of patients after endovascular repair (EVAR) of abdominal aortic aneurysm (AAA). We reviewed the electronic charts and radiologic exams of the first 125 patients (113 males, 12 females, median age of 76 years, range 48-98 years) with AAA treated by EVAR from June 1996 to November 2001. Our follow-up protocol included serial CT and US at regular intervals after the procedure (before discharge, at 1 month, and then every 6 months). Adequacy of each exam, ability to detect endoleaks, measurements of AAA diameter, and ability to determine graft patency were compared. For endoleak detection, comparison between CT and US was done using CT as the gold standard. A total of 608 exams, 337 CTs and 271 US, were performed 1 day to 5 years after endovascular aneurysm repair; 98% of CT and 74% of US were technically adequate. Contrary to CT, the proportion of adequate US exam was significantly less in patients with higher body mass index (BMI > or = 30 = 54% vs. BMI < 30 = 81%, p < 0.001) and for pre-discharge US compared to the post-discharge US (54% vs. 88%, p = 0.0005). Concurrent scan pairs were obtained in 252 instances in 107 patients (1-8 pairs per patient). Excellent correlation between AAA diameter measured on CT and US was noted (correlation coefficient of 0.9, p < 0.0001). However, agreement was poor. CT anteroposterior (AP) and transverse measurements were on average 2.9 mm (95% limits of agreement = -7 to 13 mm) and 1.8 mm (95% limits of agreement = -9 to 12 mm) greater than US. For AAA diameter change, there was no case of increase AP diameter on CT. However, in 23% (29/128 pairs of sets) of US, an increase in AAA size that could have influenced patient management (> or = 4 mm) was reported despite no change demonstrated on CT. For endoleak detection, sensitivity and specificity of US compared to that of CT was 25% and 89%. Similar sensitivity and specificity were noted when we excluded the first set (25% and 95%), sets done prior to 2000 (30% and 89%), inadequate CT or US scans (31% and 98%), or duplicate sets of results for each patient (28% and 81%). Of the 27 endoleaks missed on US in 17 patients, 2 were type I endoleaks. None of the four endoleaks seen only on US were type I endoleak. US usefulness prior to discharge was reduced by the high rate of inadequate exam, especially in obese patients. Despite the excellent correlation in AAA diameter between US and CT, there was significant disagreement in AAA diameter measurement and diameter change. Sensitivity of nonstandardized US for endoleak was low compared to CT. CT remains our primary imaging study after EVAR, but standardization of post-EVAR US technique may improve its accuracy.

Endograft infection leading to rupture of aortic aneurysm

Aortic endografting has quickly been accepted as a less morbid method of aneurysm repair. However, preservation of the aortic sac after endografting remains a liability of this procedure. Late rupture has occurred, albeit rarely. Graft infections are another rare complication of endografting. We present the first reported case, to our knowledge, of aortic rupture secondary to infection of an aortic endograft.

Aortoenteric fistula due to endoleak coil embolization after endovascular AAA repair

PURPOSE

To report a late complication associated with embolization coils used to treat an endoleak after endovascular abdominal aortic aneurysm (AAA) repair.

CASE REPORT

A 79-year-old man with a 5.8-cm AAA underwent endovascular repair with an Ancure graft in 1997. A persistent type I endoleak was identified on serial postoperative computed tomographic scans. Three transarterial coil embolization procedures were performed to treat an endoleak from the proximal and right distal attachment sites with outflow by the inferior mesenteric and lumbar arteries. Coil embolization was ultimately successful in sealing the endoleak, and the AAA decreased in size. Four years later, the patient developed an aortoenteric fistula due to erosion of the metallic embolization coils into the duodenum. The endograft was explanted and an extra-anatomical bypass inserted.

CONCLUSIONS

Coil embolization to treat endoleaks can, on rare occasions, be the cause of aortoenteric fistula. Lifelong follow-up of stent-graft patients is required.

Aortic stent-graft infection due to a presumed aortoenteric fistula

PURPOSE

To report a case of late stent-graft infection with aortoenteric fistula.

CASE REPORT

A 76-year-old Colombian man received an AneuRx stent-graft for a 5.5-cm infrarenal AAA. The aneurysm sac progressively shrank until 22 months postoperatively, when an increase in diameter was noted on magnetic resonance imaging without evidence of endoleak or air in the sac. Two months prior, the patient had developed fever and an elevated white blood cell count; he underwent a 6-week course of intravenous antibiotics. Shortly thereafter, the fever recurred, along with progressive weight loss, which prompted admission. The computed tomographic scan showed no evidence of endoleak, but gas collection was seen anteriorly in the sac; aspirated material was positive for a variety of organisms. At surgery 23 months after stent-graft implantation, pronounced inflammatory reaction and scarring were seen around the graft in conjunction with evidence of a healed duodenal perforation, suggestive of an aortoenteric fistula. The excised stent-graft was intact; no deterioration was seen. The patient had a protracted recovery but has been afebrile and asymptomatic >1 year after stent-graft explantation

CONCLUSIONS

Close surveillance after endovascular AAA repair is essential to detect late leaks, secondary migration, endotension, structural failure, and infection with or without aortoenteric fistula.