Endograft infection leading to rupture of aortic aneurysm

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 Situ Graft Replacement for a Ruptured Abdominal Aortic Aneurysm Infected with Listeria monocytogenes after Endovascular Aneurysm Repair

Listeria monocytogenes infection and rupture of the aneurysm sac, after endovascular aneurysm repair (EVAR), are both rare. We report the case of an 82-year-old man who presented with a ruptured aneurysm by infection with L. monocytogenes after EVAR. We successfully treated him by in situ reconstruction with a bifurcated expanded polytetrafluoroethylene (ePTFE) graft, with partial removal of the infected stent graft. At 30 months from the reoperation, the patient was in good health at home, with no symptoms of infection, and the gallium-67-citrate single-photon emission computed tomography/computed tomography (SPECT/CT) fusion images confirmed no fluid accumulation.

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.

Complications after endovascular aneurysm repair

Endovascular aneurysm repair (EVAR) has become an established technique for the treatment of many infrarenal aortic aneurysms. Although EVAR is obviously less invasive than open surgical repair, it is not free of complications. These can potentially result in severe morbidity or even mortality, stressing the need for an early detection and subsequent treatment. In this review article, the pathophysiology, diagnosis, and treatment of the most common complications of EVAR, with the exception of endoleaks, are described.

Late endovascular aneurysm repair infection presenting with juxatrenal aortic rupture treated with in situ aortic replacement

Infection of an endovascular abdominal aneurysm repair (EVAR) is rare but has become more prevalent with the standardization of EVAR for treating infrarenal abdominal aortic aneurysms. The understanding of this complex aortic condition has improved but still remains to evolve. We present a patient with an EVAR infection manifesting with juxtarenal aortic rupture as a result of a urinary tract infection. This report describes an unusual presentation of an EVAR infection treated with in situ aortic reconstruction and provides >1 year of follow-up.

Complete removal of infected abdominal aortic stent-graft with suprarenal fixation

Stent-graft infections after endovascular aneurysm repair are rare but can have devastating consequences. Open surgery to treat such infections is associated with considerable morbidity and mortality. Removal of the stent-graft is technically challenging, especially when it has a suprarenal fixation. Several in situ reconstructions have been described, with varying results. We report a case in which a Zenith stent-graft became infected after endovascular aneurysm repair to treat an abdominal aortic aneurysm and blue toe syndrome. The endoprosthesis was removed completely, and in situ reconstruction was performed successfully and without complications by using a rifampin-soaked Dacron graft.

The relevance of aortic endograft prosthetic infection

BACKGROUND

Vascular prosthetic graft infection is a severe complication after open aortic aneurysm repair. Reports of infected endografts are scarce. General treatment consensus with infected graft material is that it should be removed completely. The objective of this study was to describe the incidence of endograft infection after endovascular repair of abdominal (EVAR) and thoracic aortic aneurysm (TEVAR) and to report treatment options and their outcome.

METHODS

A retrospective cohort study was performed of patients endovascularly operated for abdominal and thoracic aortic aneurysm in two large hospitals (one tertiary referral center and one large community hospital) between March 1996 and June 2009. Diagnosis of infected endograft was made based on clinical findings, blood tests and cultures, imaging studies (computed tomography, fludeoxyglucose positron emission tomography), and intraoperative findings at reoperation.

RESULTS

Eleven patients with an infected endograft were identified in 1431 endovascular procedures. One other patient was referred from another hospital. Patients were aged 68 ± 9 years, and all but one were male. The median time from initial TEVAR/EVAR to the diagnosis of infection was 115 days (range, 7-3748 days), with 42% of patients presenting within 3 months after TEVAR/EVAR. Seven patients were diagnosed with endograft infection after elective TEVAR/EVAR and five after emergency TEVAR/EVAR. The incidence was significantly higher in patients that were treated in an emergency setting (0.56% vs 2.79%; P = .002), while there was no significant difference between TEVAR and EVAR procedures (1.37% vs 0.77%). All patients were initially treated with antibiotic therapy, which was complemented with surgical intervention in six patients. In four patients, the infected graft material was completely explanted. Isolated microorganisms included Staphylococcus species (n = 4), Streptococcus species (n = 4), Enterobacter cloacae (n = 1), Escherichia coli (n = 1), Pseudomonas aeruginosa (n = 1), and Listeria monocytogenes (n = 1). Median time of follow-up was 201 days (range, 6-2023 days). During the study period, three out of 12 patients died, of which two were treated conservatively (P = ns). At their last follow-up visit, seven of nine patients still used antimicrobial therapy.

CONCLUSIONS

The incidence of endograft infection is below 1%, with a mortality rate of 25%. Although consensus is that infected graft material should always be removed, this study shows no significant difference in mortality between the conservatively- and the surgically-managed group, possibly related to the small sample size. There may be a role for conservative treatment in selected cases of patients with an infected endograft.

Causes of late mortality after endovascular and open surgical repair of infrarenal abdominal aortic aneurysms

INTRODUCTION

Several reports suggest unexpectedly high rates of late abdominal aortic aneurysm (AAA) rupture occur after endovascular AAA repair (EVAR). However, a population-based study examining causes of late death after EVAR vs open surgical repair has not been performed.

METHODS

We performed a retrospective cohort study of patients undergoing infrarenal AAA repair using information from the Medicare inpatient hospital discharge records (MedPAR files), physician claim files (Part B files, 20% sample), and Medicare Denominator Files for the years 2001 to 2004. Using the Social Security Death Index, we identified all "late" deaths, defined as deaths occurring >30 days and after hospital discharge. We used the National Death Index to identify cause of death information; in particular, those deaths that were likely caused by late rupture. We compared causes of late death and survival between EVAR and open repair using Wilcoxon log-rank and rank-sum tests.

RESULTS

Between 2001 and 2004, 13,971 patients underwent AAA repair (6119 EVAR, 7852 open repair). After a mean follow-up of 1.6 years in the EVAR cohort and 1.9 years in the open cohort, mortality rates were similar across repair type (15.4% EVAR, 15.9% open repair), with an adjusted odds ratio for death after open repair of 0.98 (95% confidence interval, 0.90-1.07). Of the 2194 documented deaths, 523 occurred before discharge or <or=30 days, and 1671 occurred >30 days and after hospital discharge. Cause of death information for the 1671 late deaths was available from the National Death Index for 1515 (91%). The 15 most common codes for causes of late death were dominated by cardiac disease (atherosclerotic heart disease, acute myocardial infarction) and pulmonary disease (lung cancer, respiratory failure). Causes of late death with specific mention of aneurysm were identified in 37 patients (2.4% of all deaths), but this event was not more common in EVAR or open repair (15 [0.3%] in the EVAR group, 22 [0.3%], in the open repair group; P = .71).

CONCLUSIONS

Late deaths from aneurysm rupture after EVAR or open repair appear to be relatively infrequent and similarly distributed across procedure type. Our results emphasize that the effectiveness of EVAR is comparable to open AAA repair in preventing aneurysm-related death.

Aortic endograft infection due to Pasteurella multocida following a rabbit bite

Abdominal aortic endograft infection is a serious complication after an endovascular abdominal aortic aneurysm repair. Pasteurella multocida, a gram-negative bacterium, is a commonly found organism in the mouth flora of many house pets. We report a case of an aortic endograft infection caused by P multocida after a rabbit bite. Successful treatment was performed by extra-anatomic revascularization followed by endograft removal.

Primary Aortoappendicular Fistula Arising from an Infected, Chronic, Contained, Ruptured Abdominal Aortic Aneurysm

Gastrointestinal bleeding can be caused by a variety of pathologies. Primary aortoappendicular fistula is rare and, in our case, arose in addition to a chronic contained rupture sac of an abdominal aortic aneurysm. Clinical diagnosis is difficult. Aortic aneurysmorrhaphy along with extensive debridement and emphasis on antibiotic therapy is curative.

Diagnosis and treatment of prosthetic aortic graft infections: confusion and inconsistency in the absence of evidence or consensus

Prosthetic aortic graft infections represent a major diagnostic and therapeutic challenge. Although a combination of clinical assessment, imaging and microbiological investigations is usually helpful, there are no agreed criteria to confirm a diagnosis. Potential pathogens isolated from superficial specimens may be misleading but influence the choice of antimicrobial agents. Removal of the infected material is strongly recommended. However, this is not always possible in the very debilitated or clinically unstable patient. The choice of which antimicrobial agents to administer as empirical or definitive therapy and the duration of treatment are unclear. A multi-disciplinary group is required to offer guidance, based on what evidence there is, and to provide expert consensus (as is the case for infective endocarditis) to optimize the management of these difficult infections.

Late Surgical Conversion After Thoracic Endograft Failure due to Fracture of the Longitudinal Support Wire

PURPOSE

To report complications from a thoracic endograft wire fracture and early experience with elective conversion after thoracic endografting.

CASE REPORT

A 43-year-old man underwent urgent endovascular repair of a symptomatic post-traumatic thoracic aneurysm in 1999. The patient had been involved in a car accident 14 years before. He developed clinical and radiological signs of graft infection 46 months after stent-graft implantation. Multidetector computed tomography confirmed a fracture of the longitudinal support wire in the Excluder thoracic stent-graft. Additionally, radiological signs of suspected endograft infection were described. Due to concerns over a potential chronic infection, the stent-graft was successfully excised, and a polyester graft was implanted 50 months after primary endovascular repair.

CONCLUSIONS

Recognition or strong suspicion of endograft infection requires conversion with removal of the device. Long-term follow-up after endografting is necessary to assess material fatigue that undermines the durability of these implants.