The pathogenesis of vascular graft infection

Modified upside-down technique with Gore tapered iliac limbs for isolated iliac artery aneurysms

PURPOSE

To describe the off-label use of tapered iliac limbs for the treatment of isolated iliac aneurysms with proximal landing zone significantly larger than distal landing zone.

TECHNIQUE

Inversion of a Gore Excluder tapered leg (W. L. Gore & Associates Inc, Flagstaff, Arizona) with a modified upside-down technique is described. The endoprosthesis, with the olive at the tip of the releasing system previously cut, is inserted in a tip-to-tip fashion into a 15 Fr introducer sheath. The graft is released inside the introducer. An 18 Fr introducer sheath is advanced up to the proximal sealing zone. Following the removal of the 18 Fr dilator, the 15 Fr introducer with the pre-released graft is inserted co-axially into the 18 Fr introducer. A pre-cut 15 Fr dilator is brought up to the endograft and used as a pusher. A pull-back maneuver of the co-axial system, countertractioning with the dilator maintained in position, allows the delivery of the endograft.

CONCLUSION

This technique might offer a feasible option in case of endovascular exclusion of isolated iliac artery aneurysms with significant landing zone diameter mismatch. Extracorporeal inversion is time-saving and could be safer in terms of graft damage and infection.

Vascular Graft Infections With Candida: A Factor for Increased Mortality in in-situ Reconstructions

BACKGROUND

The empiric antibiotic regimen started after deep cultures and explantation of the graft mostly do not cover antifungals. We retrospectively studied the outcome of candida compared to non-candida VGI and assessed whether these results could justify the addition of antifungals to the empiric antibiotics in the early postoperative period.

METHODS

All patients treated for infected aorto(ilio)femoral graft with excision and reconstruction at the vascular department of University Hospitals Leuven between January 2010 and 2017 (n = 56) were studied retrospectively. Patients were allocated to the candida group (n = 10) or non-candida group (n = 46) according to the presence of Candida in deep culture isolates.

RESULTS

All-cause mortality was significantly higher in the candida group compared to the non-candida group. All-cause 30-day mortality was 40% and 13% for both groups respectively (P = 0.066). At 5 years this was 90% and 46% respectively (P = 0.014). In the candida group 6 patients (60%) had to be revised in the operating room due to bleeding, compared to 5 patients (11%) in the non-candida group (P = 0.002).  Two patients (20%) and 5 patients (11%) had to be readmitted to the ICU, respectively.

CONCLUSION

Survival of candida related VGI is significantly worse, especially in the first 5 postoperative months. This could justify the addition of an antifungal to the early empiric postoperative antibiotic cocktail, especially in patients with an aorto-enteric fistula. A cost-benefit analysis could be useful to evaluate the yield.

[Prosthetic repair of the aorta with a cadaveric homograft for infection of bifurcated synthetic vascular prosthesis]

Infection of arterial vascular grafts is a rare but utterly severe complication in vascular surgery. Therapeutic policy in patients with graft infection has not been standardized, to be determined individually. One of the variants of surgical treatment is considered to be repeat aortic repair using a cadaveric graft. Presented in the article is a clinical case report concerning a 60-year-old male patient previously subjected to aortofemoral bifurcation bypass grafting with stage IV ischaemia of lower limbs according to the Pokrovsky-Fontaine classification. In the early postoperative period the events of critical ischaemia were not arrested. Due to the presence of a block of the femoropopliteal segment, as the second stage 3 days after the primary operation, the patient underwent autovenous femoropopliteal bypass grafting with a reversed autovein above the knee-joint fissure. The clinical course of critical ischaemia of the limb was relieved. During subsequent 8 months of follow up his state remained stable. Eight months after the primary operation he developed purulent discharge from the postoperative scar on the left femur. In the setting of the Purulent Surgery Department, the patient was emergently subjected to opening and drainage of the abscess of the postoperative scar. On the bottom of the wound there was a freely lying branch of a synthetic vascular prosthesis. Computed tomography revealed infection of the entire synthetic prosthesis and aneurysms of distal anastomoses. Given extremely high risk for the development of arrosive haemorrhage, a decision was made on operative treatment - repeat prosthetic repair of the abdominal aorta with a cadaveric allograft. At the Vascular Department of the Clinic of Faculty Surgery, laparotomy was performed, with removal of the infected graft, followed by debridement of the retroperitoneal space and repeat aortofemoral bifurcation prosthetic repair of the abdominal aorta with a cadaveric allograft. The wound healed with first intention. There was no evidence of infectious process relapse. The patient was discharged on postoperative day 15 in a satisfactory condition. The duration of follow up amounted to 6 months. The control examination showed that the pain-free walking distance was 500 m. Doppler ultrasonography demonstrated that the graft was functioning, with no signs of either anastomotic aneurysms or suppuration of the retroperitoneal space.

Microbial evolution of vascular graft infections in a tertiary hospital based on positive graft cultures

BACKGROUND

Vascular graft infections are a serious complication in vascular surgery. Correct antibiotic therapy targeted to the most likely infecting species is essential to treat these patients, although the bacterial epidemiology and pathogenesis are still not completely understood. We analyzed the behavior of vascular graft infections and the microbiologic patterns of resistance.

METHODS

A 10-year (2008-2018), single-center, retrospective cohort study was performed of all patients admitted with vascular graft infection identified by positive direct graft cultures. An extensive microbiologic study was performed to analyze the bacterial strains, antibiotic resistance and sensitivity, and prevalence stratified by the year.

RESULTS

A total of 72 vascular graft infections with positive graft cultures occurring in 65 patients were found. Their mean age was 67 ± 9.6 years, and 85% were men. Infection-related mortality was 11%. Of the 65 patients, 14 had undergone aortobifemoral bypass, 13 axillofemoral bypass, 5 femorofemoral bypass, 27 femoropopliteal bypass, and 4 femoral endarterectomy with synthetic patch angioplasty. The median interval from the index procedure to infection was longer for intracavitary than for extracavitary grafts (P = .011). Of the 72 infections, 48 were monomicrobial and 24 were polymicrobial. Gram-negative bacteria were predominantly identified in intracavitary graft infections (54%). In contrast, gram-positive bacteria were most frequent in the extracavitary graft group (58%). Multidrug-resistant bacterial species occurred more frequently in early graft infections (P = .002). Throughout the study duration, an overall decrease in gram-positive infections and an increase in gram-negative infections was observed, especially in extensively drug-resistant strains. A similar progression was found in all nosocomial infections.

CONCLUSIONS

The present study has shown that vascular graft infection microbiology changed in accordance with graft location and interval to infection from revascularization surgery and had also evolved over the study period with patterns similar to those for all nosocomial infections. This highlights the importance of studying the specific microbiology of each healthcare center and its relationship to vascular graft infections to achieve the best treatment possible.

Vascular Graft Infections: An update

Vascular graft infection is a devastating complication of vascular reconstructive surgery. The infection can occur early in the postoperative period and is largely due to intraoperative contamination or by contiguous extension from a nearby infection. It can also occur years after implantation. Staphylococci remain the most common organisms and biofilm production makes eradication difficult. Factors commonly reported to predispose to vascular graft infection are periodontal disease, nasal colonization with Staphylococcus aureus, bacteremia, certain graft characteristics, diabetes mellitus, postoperative hyperglycemia, location of the incision, wound infection, and emergency procedure. Management consists of antibiotic and surgical therapy. Preventive methods are described.

The "3M" Approach to Cardiovascular Infections: Multimodality, Multitracers, and Multidisciplinary

Cardiovascular infections are associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management, as early treatment improves the prognosis. The diagnosis cannot be made on the basis of a single symptom, sign, or diagnostic test. Rather, the diagnosis requires a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data. The application of multimodality imaging, including molecular imaging techniques, has improved the sensitivity to detect infections involving heart valves and vessels and implanted cardiovascular devices while also allowing for early detection of septic emboli and metastatic infections before these become clinically apparent. In this review, we describe data supporting the use of a Multimodality, Multitracer, and Multidisciplinary approach (the 3M approach) to cardiovascular infections. In particular, the role of white blood cell SPECT/CT and [¹⁸F]FDG PET/CT in most prevalent and clinically relevant cardiovascular infections will be discussed. In addition, the needs of advanced hybrid equipment, dedicated imaging acquisition protocols, specific expertise for image reading, and interpretation in this field are discussed, emphasizing the need for a specific reference framework within a Cardiovascular Multidisciplinary Team Approach to select the best test or combination of tests for each specific clinical situation.

The Marriage of Sartorius and Tensor Fasciae Latae in Treating Vascular Prosthetic Graft Infections

Background:

Vascular prosthetic graft infection in the groin is associated with high morbidity and mortality. This article presents a case series on the use of 2 flaps in the treatment of this condition.

Methods:

Five patients, mean age 65 years (range, 49–74 years), with significant comorbidity were treated for an exposed and infected vascular prosthetic graft in the groin with a combination of sartorius muscle (SM) flap and tensor fascia lata (TFL) myocutaneous flap after debridement and start of microbiologic culture–guided antibiotic treatment. The SM flap was used to cover the exposed graft. To obtain stable wound coverage, the SM and remaining groin defect were closed with a pedicle TFL flap.

Results:

All flaps survived, with only 1 TFL flap suffering a small tip necrosis. All patients obtained stable wound coverage. Donor-site morbidity was minimal. During the follow-up, mean 46 months (range, 15–79 months), 1 patient had a recurrence after 15 months due to a kink in the elongated prosthetic graft that protruded through the skin alongside the SM and TFL flaps.

Conclusions:

The combination of SM and TFL flaps could be a new treatment option for patients who have an exposed and infected vascular prosthetic graft in the groin. This flap combination could also be used as a prophylactic procedure for those patients with a high risk to develop such a serious complication.

N, Aerts NR. Morbidity and mortality associated with arterial surgery site infections by resistant microorganisms

Background:Surgical site infection is a severe complication of peripheral vascular surgery with high morbidity and mortality rates.Objective:To evaluate the morbidity and mortality of infections of peripheral artery surgery sites caused by resistant microorganisms.Methods:This was a prospective study of a cohort of patients who underwent peripheral artery revascularization procedures and developed surgical site infections between March 2007 and March 2011.Results:Mean age was 63.7 years; males accounted for 64.3% of all cases. The overall prevalence of bacterial resistance to antimicrobials was 65.7%. The most common microorganism identified was Staphylococcus aureus (30%). Comparison of the demographic and surgical characteristics of both subsets (resistant versus non-resistant) detected a significant difference in length of preoperative hospital stay (9.3 days vs. 3.7 days). The subset of patients with infections by resistant microorganisms had higher rates of reoperation, lower numbers of limb amputations and lower mortality, but the differences compared to the subset without resistant infections were not significant. Long-term survival was similar.Conclusions:This study detected no statistically significant differences in morbidity or mortality between subsets with surgical wound infections caused by resistant and not-resistant microorganisms.

Infections in vascular surgery

Infections in vascular surgery are usually of multifactorial nature resulting from a complex interplay of patient, surgical and environmental factors. Preventative measures initiated from the stage of pre-operative screening, maintenance of patient homeostasis and the use of organism-directed antibiotics can contribute to reduce infection rates. Graft preservation techniques are becoming increasingly popular as a method to treat established graft infections. In this article we report on the current trends and techniques on the management of infections in vascular surgery. Ongoing studies are required to continue to accumulate data on the effectiveness of these techniques.

Prevalência de resistência bacteriana nas infecções de ferida operatória em cirurgia arterial periférica

CONTEXTO: A infecção de sítio cirúrgico é uma complicação grave da cirurgia vascular periférica. O recente aparecimento de microorganismos resistentes e agressivos gera uma nova preocupação com relação ao manejo dessas infecções. OBJETIVO: Verificar a prevalência de resistência bacteriana, a epidemiologia, os possíveis fatores associados e o padrão de resistência nas infecções de ferida operatória das cirurgias arteriais periféricas. MÉTODOS: Estudo de prevalência, envolvendo 40 pacientes portadores de infecção da ferida operatória e submetidos à cirurgia de revascularização arterial periférica no período de janeiro de 2007 a maio de 2008. RESULTADOS: Participaram do estudo pacientes com média de idade de 64,2 anos, predominantemente do sexo masculino (70%). A prevalência geral de resistência bacteriana foi 72,5%, e de multirresistência, 60%. O microorganismo mais freqüentemente isolado foi o Staphylococcus aureus (40%), sendo 11 das 16 culturas (68,7%) resistentes à oxacilina. As taxas de resistência aos principais antimicrobianos testados foram: ampicilina, 85,7%; cefalosporina, 76,9%; oxacilina, 65%; e ciprofloxacina, 62,5%. Não foi identificada resistência à vancomicina e ao imipenem. CONCLUSÕES: Os achados deste estudo sugerem que a resistência bacteriana é um problema atual e muito prevalente nas cirurgias arteriais periféricas. O Staphylococcus aureus segue sendo o principal patógeno envolvido, demonstrando altas taxas de resistência. A vancomicina e o imipenem seguem sendo as principais opções terapêuticas para esse tipo de infecção.

Laparoscopic Diagnosis and Treatment of Aortic Vascular Prosthetic Graft Infections in a Porcine Model

OBJECTIVES

To study the feasibility and efficacy of experimental laparoscopy in the diagnosis of aortic graft infection in pigs.

MATERIAL AND METHODS

Eight pigs had an aortic tube graft implanted and inoculated with either 5 x 10(4) or 10(6) CFU of Staphylococcus aureus ATCC 29213. Laparoscopy was performed after a median of 20 days with debridement and sampling for bacterial culture. Thereafter, the grafts were locally soaked in rifampicin and postoperatively, the pigs received rifampicin and ciprofloxacin orally for two weeks and were then sacrificed.

RESULTS

All pigs developed graft infection. One pig died from severe clostridial septicaemia before laparoscopy could be performed. The remaining pigs had all samples for bacterial culture taken by laparoscopy from the inflamed tissue. The temperature dropped significantly after laparoscopy, and no macroscopic signs of infection presented at autopsy. However, only culture from one pig was without S. aureus at autopsy.

CONCLUSIONS

Laparoscopy is a potential diagnostic tool for aortic graft infection and also affords the opportunity to carry out bacteriological sampling and local antibiotic treatment. The efficacy of laparoscopic treatment needs further evaluation.

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.

Prevalence of MRSA in Emergency and Elective Patients Admitted to a Vascular Surgical Unit: Implications for Antibiotic Prophylaxis

OBJECTIVES

MATERIALS AND METHODS

200 consecutive emergency/transfer and 150 consecutive elective patients admitted between April 2004 and January 2005, were studied. Data was obtained from departmental Morbidity and Mortality records and the computerised laboratory medicine information system.

RESULTS

261 (75%) of the 350 patients were screened for MRSA on admission (target 100%). The proportions of emergency/transfer and elective patients screened were similar (78% and 72% respectively). The prevalence of MRSA carriage detected by admission screening in emergency/transfer patients 30/153 (20%), was significantly higher (p<0.0001) than in elective patients 2/108 (2%). A simple decision analysis model suggests that gentamicin should be used when the prevalence of MRSA reaches 10% and vancomycin when the prevalence reaches 50%.

CONCLUSIONS

The high prevalence of MRSA colonisation in emergency/transfer patients has important implications for pre-operative antibiotic prophylaxis.