Minimising arteriovenous graft infections and preserving vascular access using partial graft excisions

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The findings of a new retrospective review carried out by Suh Min Kim (Dongguk University Ilsan Hospital, Goyang, Korea) and colleagues that aimed to establish an appropriate treatment strategy for arteriovenous graft (AVG) infection have been published in the Journal of Vascular Access. The findings indicate that partial graft excision could be a treatment option to achieve both eradication of AVG infection and preservation of vascular access in selected patients.

The authors acknowledge that infection is a common complication in an arteriovenous graft (AVG); the reported infection rate being fivefold higher compared to an autogenous arteriovenous fistula. Prosthetic graft infections can lead to prolonged use of a catheter, a long duration of hospitalisation and life-threatening sepsis.

Both eradication of infection and vascular access salvage are important considerations—making treatment of AVG infection particularly challenging for vascular surgeons. With regards to treatment, the authors write: “It is imperative to aim for balance between infection control and vascular access preservation, because of the limited anatomic options for vascular access creation.”

Traditionally, total graft excision (TGE) and the insertion of a central venous catheter are recommended until the infection is controlled. The authors report that previous studies suggest the use of a remnant cuff as a preferred method to reduce the morbidities of excision without an increased risk of recurrent infection. In addition to this, partial graft excision (PGE) with an interposition graft has been tried in order to preserve vascular access salvage in selected patients.

However, the Kim et al note the lack of data in relation to the clinical presentation and treatment outcomes in patients with an infected AVG. Furthermore, the extent of surgical excision to be performed for AVG infection remains debatable.

Therefore, the authors aimed to report their experience regarding surgical treatment of an infection AVG for haemodialysis, to compare the results of PGE and TGE, and to establish an appropriate treatment strategy for both infection control and vascular access preservation.

Kim et al carried out a retrospective review, in which a total of 50 cases of AVG infection were treated between January 2005 and June 2016. The median age was 66.5 (range 29–84) years, with 33 men and 17 women. Thirty-seven (74%) had hypertension and 23 (46%) had diabetes mellitus. The median duration for which patients had been receiving haemodialysis was 37.5 months (range 2–432).

Reviewing medical records, the authors collected data pertaining to demographics, antibiotics, pathogens, types of AVG, the interval between AVG creation, or any intervention and surgical excision and complications.

The surgical methods used in the study were total graft excision (TGE; n=34), or partial graft excision (PGE) with an interposition graft (n=16). The choice of surgical methods was determined by three factors: the presence of fever (an indication for TGE), recent history of surgical manipulation mandating complete removal, and intraoperative findings. The latter was noted as a particularly important consideration, as infected prosthetic grafts do not get encased in scar tissue—but this can be easily determined by experienced vascular surgeons.

The results of the study regarding clinical manifestations include that infection was noted at a puncture site in 22 cases, at a prior incision for surgery or endovascular therapy in 20, and abandoned (currently unused) grafts in five cases.

Additionally, infection occurred within one month after an AVG creation in only one case, while infection followed within one month of any intervention in 14 cases, and occurred more than one month after AVG creation or intervention in 35 cases. Simultaneous remote infection was identified in seven patients, two of whom underwent an operation for infective endocarditis and spondylitis.

In relation to the surgical outcomes of PGE, five patients (31.2%) having recurrent infection were treated with further graft excision; however, no patient showed life-threatening complications.

After TGE, a central venous catheter (CVC) was inserted and used for a median period of 90 days. Among the 34 patients who underwent TGE, new vascular access was created in 18 patients at a median period of two months later, and 12 patients continued to use a CVC until last follow-up or death.

Taking into account the results of the study, the authors note some important clinical implications. As seven patients had simultaneous remote infection and two required major surgery due to it, this type of infection must be suspected if or when the patient develops sustained fever or bacteremia after graft extension. Additionally, in 10% of the patients, infection involved an abandoned graft. As infection can occur at the site of abandoned vascular access, careful evaluation should take place if the patient is being assessed for fever, the authors recommend.

The final clinical implication the authors point to is regarding the use of an endovascular approach in management of an infected graft. According to the authors, this approach could potentially cause septic emboli along with serious complications; meaning the possibility of infection should be evaluated when an endovascular procedure is planned for a thrombosed graft of pseudoaneurysm.

In relation to the limitations present in the study, the authors comment that they only analysed the outcomes in surgically treated patients, whereas information on the medically treated cases were not included. An interposition graft was placed after PGE using only a polytetrafluoroethylene (PTFE) graft. However, the authors comment that it would be useful to study and compare the benefits of other types of grafts, such as cryopreserved veins. Furthermore, due to the small sample size, the authors could not compare results based on microbiological studies, such as Gram-negative species.

Irrespective of the current limitations, the authors conclude that PGE should be considered in selected patients in order to achieve both infection eradication and vascular access preservation. The presence of fever and a recent history of surgical intervention would commission the use of a TGE, while intraoperative findings of a well-incorporated graft would be an indication for PGE. Yet, the authors reiterate that due to a higher risk of recurrent infection after PGE, appropriate patient selection and sufficient surgical removal (until the surgeon encounters sterile segments) are essential factors for success. Lastly, an extended courses of antibiotics and careful wound care is warranted for effective postoperative management.

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