Aortic Vascular Graft Infection Research Articles

Management of thoracic aortic graft infections with combined omental and bilateral pectoralis major flaps

BackgroundAortic vascular graft/endograft infection (VGEI) has historically been managed through graft removal and re-replacement, but new approaches suggest vascularized tissue transfer is an effective adjunctive treatment. Here we describe our experience with treating thoracic aortic vascular graft infection with combined omental and bilateral pectoralis major myocutaneous (PMM) advancement flaps. MethodsAll patients undergoing combined flap closure by the senior author at a high-acuity cardiac surgery center from 1995-2023 were reviewed. Patients with clinical and radiographic signs of thoracic aortic vascular graft infection were included. ResultsComplete data were available for 598 patients with sternal and mediastinal wounds. Combined PMM and omental flaps were mobilized in 11 thoracic aortic vascular graft infection patients. Indications for flap management included culture-positive infection (8/11; 72.7%), dehiscence (5/11; 45.5%), drainage (7/11; 63.6%), and inability to close the sternotomy due to hemodynamic instability (5/11; 45.5%). During chest exploration, 6/11 (54.5%) underwent complete removal of the infected graft, compared to 5/11 (45.5%) who underwent graft-preserving washout and debridement. Immediate flap closure was performed in 6/11 (54.5%). Post-op complications included dehiscence (2/11; 18.2%), seroma (1/11; 9.1%), hematoma (1/11, 9.1%), abdominal hernia (1/11; 9.1%), and recurrent infection (1/11; 9.1%). One patient (9.1%) died within 30 days of sternal reconstruction from mitral valve failure tachyarrhythmia. None has undergone reoperation for flap-related complications. ConclusionsDespite significant comorbidities, low postoperative morbidity and mortality indicate that combined omental and pectoralis major flaps are a safe and effective adjunctive treatment to the antimicrobial and surgical management of select thoracic aortic vascular graft infections.

Finite element-based feasibility study on utilizing heat flux sensors for early detection of vascular graft infections

Aortic vascular graft infections have high morbidity and mortality rate, however, patients often do not show symptoms. Continuous implant surface monitoring will allow for early detection of infections on implant surfaces, which allows for antibiotic treatment prior to biofilm formation. We explore the possibility of using heat flux sensors mounted on an aortic vascular graft to sense the localized heat production at the onset of infectious growth. We apply Finite Element Model simulations to demonstrate changes of the heat transfer coefficient depending on different pulsatile flow parameters. We determine various differences, the main influence being the distance travelled from the inlet of the simulation with the highest heat transfer coefficient closest to the inlet and decreasing along the direction of travel of the fluid. The determined range of heat transfer coefficients of 200 to 4800 W/m2 was applied to a second simulation of the thermal environment of the implant. We determined the heat transfer efficiency of the aortic graft system depending on different graft materials and thicknesses. We are further able to determine that the early detection of infection is possible by comparing the simulated amount of heat flux produced locally with the resolution of a commercial heat flux sensor.

Thoracic aortic vascular graft infection: outcome after conservative treatment without graft removal.

Surgical debridement with aortic graft removal is considered the preferred treatment for thoracic aortic vascular graft infection (VGI). Conservative treatment with antibiotics only is usually reserved for inoperable patients. Due to Outpatient Parenteral Antimicrobial Therapy (OPAT) and better understanding of the antibiotic impact on biofilms, long-term targeted antibiotic therapy without graft removal may be an alternative treatment option for selected thoracic aortic VGI patients. The aim of this case series was to evaluate the outcome in patients with thoracic aortic VGI who were treated without graft removal. This single-centre retrospective cohort study evaluated patients with a thoracic aortic VGI diagnosed between 2008 and 2021 and who were treated without graft removal. The primary outcome parameter was the 6-month mortality rate after VGI diagnosis. Secondary outcome parameters were cure rates and relapse of infection. Twenty-four patients with thoracic aortic VGI who were managed without graft removal were identified. The mortality rate 6 months after VGI diagnosis was 8% (2/24); one of these deaths was infection related. The median antibiotic treatment duration was 13 months (interquartile range 15). A total of 16 patients (67%) were cured. No relapses occurred after a median of 24-month (interquartile range 32) follow-up. Intensive antibiotic treatment, without graft removal, may be a non-inferior option in patients with a thoracic aortic VGI who are not considered for surgery.

Outpatient parenteral antimicrobial therapy (OPAT) for aortic vascular graft infection; a five-year retrospective evaluation

ObjectivesAn estimated 1% of endovascular aneurysm repair (EVAR) devices become infected, carrying a high mortality rate. Surgical explantation is recommended and prognosis is guarded. This retrospective cohort analysis focuses on the role of outpatient parenteral antimicrobial therapy (OPAT) in the management of aortic vascular graft infections following EVAR.MethodsPatients who received OPAT for aortic graft infections (AGI) following EVAR from 2014 to 2018 inclusive were identified using the OPAT database. Clinical, microbiological and radiological data were collected. Survivors were followed up for a median of 36 months (range 25–60) after first presentation with infection. Outcomes were assessed.ResultsEleven cases with 20 OPAT episodes were identified: 10/11 male, median age 76 (IQR 71–81). Median time to presentation was 7 months (range 0–81 months) after EVAR. OPAT lead to a 55% reduction in length of hospital stay. One patient had graft explantation; four others had temporising measures. Eight of 11 were alive a median of 36 months after presentation with infection, having had a median of 2 re-treatments on OPAT (range 1–3). Seven of the eight survivors were on continuous suppressive oral antimicrobials; three were also intermittently on intravenous antibiotics for flares of infection. Patient/ infection outcomes were cure (1/11), improved (7/11), failure (3/11).ConclusionAGI following EVAR usually presents in the first year after graft deployment. OPAT has an important peri-operative role in patients suitable for curative surgery. OPAT followed by oral suppressive antimicrobial therapy can be a feasible long-term treatment for non-curative management of AGI. Survival in our cohort was longer than expected, and OPAT was feasible despite the complexity of these infections. OPAT can avoid multiple and lengthy hospital admissions and maximise time at home and quality of life in this cohort with life-limiting infection.

Clinical experience of positron-emission tomography in infective aortic disease.

Background Fluorine-18-fluorodeoxyglucose positron-emission tomography with computed tomography has revolutionized medical diagnosis by adding functional activity to anatomic imaging. We report our experience with this technique in patients with mycotic aortic pathology and aortic vascular graft infection. Methods We conducted a retrospective review of a prospective database of patients who underwent 18F-fluorodeoxyglucose positron-emission tomography with computed tomography for suspected infective aortic disease. From 2012 to 2016, 13 patients underwent 18F-fluorodeoxyglucose positron-emission tomography. Of these, 9 (69%) had a vascular graft infection (5 infrarenal aorta, 1 para-visceral, 2 descending, and 1 arch; 2 had previous open surgery and 7 had endovascular interventions) and 4 (31%) had a mycotic aneurysm (2 aortic arch, 1 infrarenal aorta, and 1 distal aorta and common iliac; 3 had endografts). The indications for imaging, location of pathology, 18F uptake, and clinical outcomes were analyzed. Results Eight (62%) patients had a single scan and 5 (38%) had serial scans performed. Among the 5 patients who had serial imaging, 3 showed decreased 18F uptake and 2 had increased uptake. Only one patient underwent subsequent endograft removal; the others were treated with lifelong antibiotics. There were 5 (38%) deaths on follow-up. Conclusion 18F-fluorodeoxyglucose positron-emission tomography with computed tomography could be a valuable adjunct in the diagnosis and surveillance of patients with aortic infection. Serial scans may be useful for monitoring disease activity and response to antibiotic therapy.

Evaluation of fever and infections in cardiac surgery patients.

Fever following cardiac surgery is common and may be infectious or noninfectious in etiology. In this article, we review the major causes of postoperative fever while highlighting special considerations in cardiac surgery patients. We also outline a structured approach to evaluation and present an overview of diagnostic and management considerations for mediastinitis, postpericardiotomy syndrome, prosthetic valve endocarditis, aortic vascular graft infections, and ventricular assist device infections.

In vitro efficacy of antibiotic beads in treating abdominal vascular graft infections

Abdominal aortic vascular graft infection often involves several different organisms. Antibiotic polymethyl methacrylate (PMMA) beads may be effective in controlling infection after débridement, but bacterial species identification and antibiotic susceptibility are often not available at the time of operation, generating a need for a broad-spectrum drug combination for empirical use. We sought to determine an effective antibiotic in PMMA beads for use in abdominal vascular graft infection. PMMA beads were impregnated with combinations of antibiotics, consisting of daptomycin, tobramycin, and meropenem. Antibiotics were selected on the basis of activity spectrum and heat stability. Beads were placed on separate agar plates with vancomycin-resistant Enterococcus faecalis, Klebsiella pneumoniae, Staphylococcus epidermidis, and methicillin-resistant Staphylococcus aureus. Antibiotic inhibition was recorded by use of a modified agar-based disk-diffusion method. Daptomycin alone was not active against K. pneumoniae (average = 0 mm). Tobramycin alone was not active against vancomycin-resistant E. faecalis, K. pneumoniae, or methicillin-resistant S. aureus. Tobramycin and daptomycin in combination had moderate broad-spectrum activity with 8- to 14-mm mean inhibition halos. Meropenem showed strong activity against all tested organisms with >15-mm mean inhibition halos. The addition of daptomycin to meropenem provided improved coverage of gram-positive organisms. The presence of tobramycin reduced the efficacy of meropenem. Antibiotic PMMA beads containing 10% meropenem with 2.5% daptomycin had excellent in vitro activity against typical bacterial species associated with abdominal vascular graft infections. The addition of antibiotic beads may be a useful adjunct in managing such cases. Further studies are required to determine efficacy in clinical practice.

Recommendations for Reporting Treatment of Aortic Graft Infections

The purpose of these recommendations is to provide a standard format for reporting treatment results and standardised epidemiologic data after aortic vascular graft infection to improve the comparison of clinical outcomes between different therapeutic approaches and different study populations. Analytical reporting standards for patients’ characteristics, type and extent of the disease, type of treatment and study design are described. Adherence to these recommendations will improve clinical relevance, quality and comparability of future studies dealing with aortic vascular graft infections.

Delayed aortic prosthetic reconstruction after removal of an infected graft

The amputation morbidity associated with the treatment of vascular graft infection continues to be a major clinical problem. Late amputation associated with failure of extraanatomic bypass initially required to avoid infected tissue beds might be reduced if delayed anatomic aortic prosthetic reconstruction could be safely employed. Two major concerns about this treatment option are the safety of the redo aortic reconstruction and the risk of recurrent infection in the reimplanted graft. Seven patients in whom recurrent limb ischemia or extraanatomic bypass infection developed underwent delayed aortic reconstruction using either an in-line aortic graft or supraceliac aortofemoral bypass at a mean interval of 14.5 months after removal of the infected graft. There were no perioperative deaths, and six of seven patients were well at a mean follow-up of 57 months postoperatively. All grafts remained patent throughout the follow-up period and no further amputations were required. No reimplanted graft became infected, which suggests that a reimplantation interval of 6 to 12 months may be safe. These data indicate that delayed aortic prosthetic reconstruction may be considered a safe and effective treatment option for those patients in whom limb-threatening recurrent ischemia or recurrent extraanatomic graft infection develops after treatment of aortic vascular graft infection.