Aorto-femoral graft infections: a clinical and microbiological analysis

Predictive Factors for Aortic Graft Infection: A Case-Control Study

BACKGROUND

Graft infections are one of the most serious complications in vascular surgery, with high mortality rates. Few studies addressed risk factors associated with a higher susceptibility to infection. The aim of this study is to identify perioperative factors associated with aortic graft infections (AGI).

METHODS

We designed a retrospective, case-control study from patients subjected to open aortic repair between 2013 and 2019. Cases of AGI were defined according to the management of aortic graft infection collaboration (MAGIC) criteria and matched to controls without proven infection. Demographics, hospital complications, and laboratory workups were assessed. Predictors of AGI were identified through univariate and multivariate analysis.

RESULTS

Most graft infections occurred in a late period (n = 17; 85%), after a median interval of 13.5 months interquartile range (IQR 1.5-36). Gram-negative bacteria were most frequently isolated in infected grafts, namely Enterobacteriaceae (n = 12). Cases had significantly lower postoperative serum albumin levels (1.9 g/dL vs. 2.4 g/dL; P = 0.002). Alcohol abuse, malignancy, prolonged lengths of stay, wound infection and dehiscence, in-hospital infection, postoperative heart failure or bowel ischemia were significantly correlated to the onset of AGI. In the multivariate analysis, prolonged hospital stays odds ratio (OR 1.05; P = 0.03), malignancy (OR 5.82; P = 0.03) and alcohol abuse (OR 42.41; P = 0.002) maintained a significant association.

CONCLUSIONS

The risk of AGI seems to be higher in patients with concurrent malignancy, alcohol abuse or prolonged hospital stays. Strategies to mitigate this complication in these patients are of utmost importance.

Aortic Prosthesis-Associated MDR Pseudomonas Infections as a Diagnostic and Therapeutic Challenge

Endovascular prostheses are used to treat life-threatening conditions such as ruptured aortic aneurysms. Prosthetic infection cause significant morbidity and mortality, posing important diagnostic and therapeutic challenges. It is particularly difficult to diagnose and, in the era of multidrug resistance (MDR), these type of infections may become even more difficult to treat. Herein, we reported a case of a secondary prosthetic endovascular infection following repeated bacteremia episodes from a urinary source. This case illustrates an MDR Pseudomonas aeruginosa aortic infection that was difficult to diagnose with no oral antibiotic treatment options.

Open Conversion after Aortic Endograft Infection Caused by Colistin-Resistant, Carbapenemase-Producing Klebsiella pneumoniae

A 62-year-old man presented with fever, abdominal pain, and malaise 13 months after emergency endovascular aortic repair. Computed tomographic angiograms showed a periprosthetic fluid and gas collection, so infection was diagnosed. Open conversion was performed, involving endograft explantation and in situ aortic reconstruction. Cultures and the explanted prosthesis were positive for carbapenemase-producing Klebsiella pneumoniae, resistant to colistin. Because of the sparse data on endograft infections caused by this pathogen, we placed the patient on an empiric double-carbapenem regimen for 4 weeks. Symptomatic recovery occurred after 21 days. On the 30th day, we deployed a stent to treat a new pseudoaneurysm. Three years later, the patient had no signs of persistent or recurrent infection. We think that this is the first report of aortic endograft infection caused by colistin-resistant, carbapenemase-producing K. pneumoniae.

Gasless Videoendoscopic Implantation of an Aortobifemoral Vascular Prosthesis via a Transperitoneal versus Extraperitoneal Approach: An Experimental Study

Purpose:

To report progress in the development of a new minimally invasive surgical technique for aortobifemoral grafting utilizing gasless videoendoscopy.

Methods:

In an experimental study, aortobifemoral Dacron vascular prostheses were implanted in 20 human cadavers using videoendoscopic techniques in both transperitoneal and extraperitoneal approaches. Rather than inducing pneumoperitoneum, the abdominal wall was elevated with an electrically powered lifting system.

Results:

Each approach was utilized in 10 cadavers for implantation of 20 aortobifemoral grafts under endoscopic guidance in a gasless field. Average operative time for the transperitoneal approach was 3.8 hours (range 3.0 to 5.5), slightly less than the average 4.1 hours (range 3.0 to 6.0) for the extraperitoneal access. Both access routes provided adequate visualization of the operative field.

Conclusions:

Advantages of gasless endoscopy include the use of conventional instruments and the potential benefits associated with a minimally invasive approach. Optical magnification facilitates suturing of the femoral anastomosis, improves examination of the vascular walls, and allows a more accurate suturing technique.

Infección asociada a prótesis vascular: manejo exitoso sin retirada de prótesis

INTRODUCTION

Removal of graft with intravenous antibiotics is traditionally considered the most effective treatment of vascular graft-associated infections. However, an increasing number of reports suggests that this complication can be effectively treated without graft removal.

METHODS

A prospective study to evaluate the outcome of conservative management of vascular graft-associated infection seen in our center was performed. The diagnosis of graft-associated infection was based on microbiological tests, and imaging studies. In our study, patients were hemodynamically stable with functioning vascular graft as per clinical and imaging evaluations. Conservative management included antibiotic treatment and local debridement without removal of vascular graft.

RESULTS

Fourteen patients with vascular graft-associated infection were enrolled in our study. Eleven out of 14 patients (78.6%) responded successfully to conservative management. Treatment failure was reported in 3 patients, 2 of whom required graft removal. After a two-year follow-up, these 14 patients were clinically stable without recurrence of infection.

CONCLUSIONS

Our study has revealed that conservative management of vascular graft-associated infection seems to be effective and should be considered in hemodynamically stable patients with functioning vascular graft.

The role of preoperative Tc-99m HMPAO-labeled leukocyte total-body scans in aortic prosthetic reconstruction

PURPOSE

This study was performed to evaluate the utility of Tc-99m HMPAO-labeled leukocyte total-body scans (TBLS) for detecting remote septic foci before operation in patients undergoing aortofemoral vascular surgery.

MATERIALS AND METHODS

Fifty-eight patients were screened before operation for inflammatory or infective disease, and a clinical score was assigned to each patient. Each patient had TBLSs. The relation between the clinical score and the TBLS result was determined. Patients with positive results of the TBLSs were examined, and the causes of these findings were treated before surgery.

RESULTS

Ten of the 58 (17%) patients had a positive result of TBLSs. Of 31 patients with a clinical score of zero, 3 had positive findings of TBLS. No TBLS was positive in the 13 patients with a clinical score of 1. TBLS findings were positive in 7 of 14 of the combined patients with clinical scores of 2, 3, or 4. None of the patients showed signs of prosthetic vascular graft infection during the postoperative follow-up period.

CONCLUSIONS

In conclusion, TBLSs can be used before aortofemoral vascular surgery, but only in patients with high clinical scores for inflammatory or infective disease to identify relevant infective foci that could cause vascular graft infection.

Conservative surgery for aortic graft infection

Surgery for aortic graft infection is a major challenge often characterized by the need for ingenuity and improvisation. Traditional treatment is by total graft excision and extra-anatomic bypass. In situ replacement of the infected graft using either autogenous tissue or antibiotic-impregnated Dacron is effective in selected cases but it is not clear when such conservative treatment may be employed. Graft excision and thorough débridement of infected tissue are important, whichever technique is used. It would seem unwise to perform in situ reconstruction unless the remaining operative field is free from contamination. When in situ replacement is selected, a rifampicin-soaked Dacron graft is the easy option, but large studies will be needed to determine whether this is a suitable long-term alternative to conventional treatment.

Gasless videoendoscopic implantation of an aortobifemoral vascular prosthesis via a transperitoneal versus extraperitoneal approach: an experimental study

PURPOSE

To report progress in the development of a new minimally invasive surgical technique for aortobifemoral grafting utilizing gasless videoendoscopy.

METHODS

In an experimental study, aortobifemoral Dacron vascular prostheses were implanted in 20 human cadavers using videoendoscopic techniques in both transperitoneal and extraperitoneal approaches. Rather than inducing pneumoperitoneum, the abdominal wall was elevated with an electrically powered lifting system.

RESULTS

Each approach was utilized in 10 cadavers for implantation of 20 aortobifemoral grafts under endoscopic guidance in a gasless field. Average operative time for transperitoneal approach was 3.8 hours (range 3.0 to 5.5), slightly less than the average 4.1 hours (range 3.0 to 6.0) for the extraperitoneal access. Both access routes provided adequate visualization of the operative field.

CONCLUSIONS

Advantages of gasless endoscopy include the use of conventional instruments and the potential benefits associated with a minimally invasive approach. Optical magnification facilitates suturing of the femoral anastomosis, improves examination of the vascular walls, and allows a more accurate suturing technique.

Relevance, pathogenicity and virulence of microorganisms in implant related infections

It is impossible to imagine modern medicine today without indwelling devices of various kinds. The time that these implants or prostheses remain in the patient's body can vary from a few hours, e.g. intravenous catheter, to his entire life, e.g. hip prosthesis, heart valve. Besides the indisputable use and advantages of this type of medical intervention for the patient, e.g. saving his life or improving its quality, the associated complications should not be overlooked. One of the most frequent and significant complications of implant surgery is the manifestation of infection in the tissue around the implant. That infection occurs is not surprising since the indwelling devices predispose to bacterial and mycotic infection on the one hand and impede its eradication on the other. The consequences of infection for the patient may mean the loss of regained mobility and independence, hospitalization for sepsis, or even death. Microbes per se are not necessarily pathogenic, however, there are numerous virulence factors which affect the degree of pathogenicity of the microorganisms. These include, for example, various enzymes, (e.g. catalase, hyaluronidase, collagenase and other proteases), and specific surface structures, e.g. the polysaccharide capsules of pneumococci or the lipopolysaccharides of Gram negative bacteria, and the production of bacterial toxins, e.g. leucozidin, streptolysine. The strategies which the pathogenic bacteria employ in their efforts to occupy the host include adherence, penetration and multiplication, antiphagocytosis and serum resistance, the formation of siderophores, antiimmunity, and cell and tissue damage. An attempt will be made here to present an overview of this multifactorial event in which the host obviously plays an important role.