Management of Infected Grafts
Brittany Hedgepeth PGY1
Occurrence
Occurrence
- Open aortic grafts have infection rates between 0.5-3%
- Endovascular stent- grafts have an infection rate of 0.2%-5%
- Lower extremity grafts have a similar infection rates, 4.7-6% with higher rates in the groin
- Infection occurs at higher rates in grafts placed for dialysis access, 9-20%
Diagnosis
Diagnosis
- Suspicion is raised for graft infection through good history and physical
- Things to keep in mind: obvious exposure of graft, erythema, cellulitis, swelling or other signs of infection
- If infection is not obvious but still suspected imaging can be used
Imaging
Imaging
- CT is the current gold standard
- Look for perigraft fluid, soft tissue changes, fat stranding, loss of tissue plains, ectopic gas, and psuedoaneurysm
- US is initial test of choice for extracavitary grafts
- Look for perigraft fluid, psuedoaneurysm, hematoma, and soft tissue masses, and assess graft patency
- Tagged white blood cell scans & positron emission tomography scanning are also used
Treatment
The basic approach falls into 3 categories:
- Graft excision with revascularization
- Graft excision without vascularization
- Graft preservation
Treatment
Extraanatomic bypass
Graft excision w revascularization
- Extraanatomic bypass with excision of all prosthetic material for infected intracavitary abdominal grafts has traditionally been the gold standard for repair
- The most common procedure performed is an axillofemoral graft with a femoral-femoral bypass or an axillobifemoral bypass using expanded polytetrafluoroethylene as conduit
- If the superficial femoral artery or profunda is used as the outflow vessel, the approach to these vessels should be lateral to the sartorius muscle to avoid contamination from the femoral triangle
Complications
- reinfection (3%–37%), early mortality, limb loss (3%–15%), and the dreaded aortic stump blow-out with life-threatening hemorrhage (3%–24%).
Complications
In Situ Antibiotic Impregnated Graft Replacement
- Acceptable for patients with low-virulence pathogens, aortoenteric fistula, or erosion with impending hemorrhagic catastrophe
- Procedure includes gaining proximal and distal control, excision of all graft material, debridement, irrigation with antibiotic solution, and immediate replacement with a new prosthetic graft.
- The prosthetic materials most commonly used are Dacron soaked in rifampin or silver-impregnated prosthetic grafts
Benefits
Benefits
- Short operating times
- Excellent patency/durability
- Low amputation /mortality rates
- Can be used in emergency settings
In Situ Cryopreserved Allograft Replacement
- The procedure consists of removing all infected graft material, debridement , antibiotic irrigation and new conduit placement with cryopreserved aorta
- The disadvantage of this procedure is lack of availability and cost as well as the time necessary for implantation, which requires thawing the frozen product before use.
- Long-term patency rates of this graft are less than that of prosthetic material but better than extraanatomic bypasses.
- Amputation rates are low (less than 8%), and mortality varies widely (9%–56%).
In Situ Venous Autograft
- Also known as neo-aortoiliac system (NAIS) and consists of reconstructing the aortoiliac system using femoral-popliteal vein as conduit
- Advantages include use of autograft, in-line flow, complete removal of infected endograft, no concerns for immunogenicity of the conduit, and likely eradication of the infection.
- Disadvantages include procedure length and the complications that come with deep vein harvest, notably leg swelling and potential venous compartment syndrome that may require fasciotomies.
- Long term reinfection rates are close to 0% and mortality rates following the NAIS procedure range from 8% to 33%
Graft Excision w/o Revascularization
Graft Excision
w/o Revascularization
- Can be considered in cases where the initial procedure was done for claudication or in a case where the graft is thrombosed and the patient does not have critical limb ischemia.
- Typically the arteriotomy left behind following the graft removal is repaired commonly with a vein patch to not narrow the vessel.
- It's important to continue monitoring the limb postoperatively as collateral flow may have been interrupted.
Graft Preservation
Graft Preservation
- Through wide local debridement
- Infected prosthetic material is left behind, and this technique should be reserved for limited circumstances.
- Patent grafts with a short segment involved with less virulent infections are a prime example of one where preservation can be considered.
- This may need to be done several times to ensure there is healthy uninfected tissue.
Infected Dialysis Access Grafts
Depiction of an ePTFE Arteriovenous Fistula Graft in a Human Arm (left); and Needle inserted in a Graft (right) (Source: W. L. Gore & Associates, www.goremedical.com)
Infected Dialysis Access Grafts
- Patients often present with malaise, fevers, and evidence of erythema or purulent drainage from previous access sites.
- Once graft infection is suspected, blood cultures should be taken and the patient should be placed on empiric antibiotics
- With the repeated use, there is a high chance of developing a pseudoaneurysm or hemorrhage in these patients.
- All infected material is removed
- Veinotomy can be closed primarily and vein patch can be used to close the artery
- Place temporary dialysis access until infection is cleared