Answer: The National Kidney Foundation Clinical Practice Guidelines for AV Access placement recommend that 50 percent of new dialysis patients have an AV fistula.1 One reason for this is that the incidence of infection is lower in a fistula than in a graft. 2 Dialysis patients spend an average of 13 days in the hospital each year. 3 Those with an infected AV graft spend an average of 7.5 days in the hospital. Nine to 20 percent of AV grafts become infected. 4 These infections can be severe and often lead to a loss of the graft. Infections from a graft can spread throughout the body and may cause sepsis, a toxic condition resulting from the spread of bacterial or their products from a focus of infection, and even death.

The first signs of a graft infection may be redness, drainage and pain overlying the graft, skin erosion resulting in exposure of the graft or a combination of the above. The patient should have a culture of any drainage. Blood cultures should be obtained and the patient started on intravenous antibiotics. Bacteria are generally divided into two groups based upon their staining characteristics with the Gram stain. Bacteria are Gram-positive if the bacteria stain blue and Gram-negative if they stain red. Antibiotic coverage for graft infections should initially cover both of these types of bacteria, and can be adjusted once culture results return. If the infection is superficial, only involving the surrounding skin but not the actual graft, antibacterial therapy is all that is necessary. If the infection involves the graft, the local portion that is infected should be surgically removed. If the infection is extensive, then the entire graft will need to be removed. The Kidney Disease Outcomes Quality Initiative (K/DOQI) clinical practice guidelines also recommend that a newly placed graft should be treated with both antibiotics and graft removal regardless of the extent of infection. Antibiotic therapy should be continued for several weeks.1

The most common cause of graft infections is bacteria known as Staphylococcus aureus.5 This Gram-positive organism can be very vicious and affect other organs as well as the graft, spreading to joints and heart valves. Once the heart valves are involved, the infection can spread through collections of bacteria, known as septic emboli, that travel throughout the arterial side of the blood stream to any organ, including the brain.

The entire graft should be removed in the following conditions: the graft is less than one month old, graft involvement by infection is extensive and graft infection is accompanied by sepsis or hemorrhage. When the infected graft is removed, the wound is generally not closed as with most surgeries, but is left open and heals more slowly. A temporary catheter is placed, and several days after the patient has fully recovered, a new access can be attempted.2

Sepsis is characterized by unstable blood pressure, a widened pulse pressure (a large difference between the systolic – top number and the diastolic – bottom number), a rapid pulse rate, fever and an elevated white blood cell count. It is characterized by positive blood cultures, which identify the bacteria in the blood. Bacteria in the blood are known as bacteremia, but when symptoms are present, we generally use the term septicemia. Patients with sepsis are generally very weak and have no appetite. The Gram-positive organisms may lead to constriction of peripheral blood vessels, while the Gram-negative organisms can cause the peripheral blood vessels to dilate. Both ultimately cause circulatory collapse and shock. Patients with early bactericidal, destroying bacteria, who are not rapidly treated, are prone to develop the resulting complications of more serious and widespread infection.

Sometimes an ultrasound of the infected graft can be performed prior to the operative procedure. Fluid around the graft signifies infection. This test can be useful when a local infection is suspected. Occasionally, the cuff of the graft can be left connected to the artery and vein, making the insertion of a patch graft possible and avoiding the placement of a temporary dialysis catheter.6

Prevention of a graft infection requires team work. The patient, family and medical team each have specific duties to prevent an infection and to detect it early through cautious vigilance.

Patients and their medical teams are advised to wash hands regularly using the Centers for Disease Control and Prevention (CDC) recommended guidelines for hand washing, hand hygiene education and hand hygiene motivation. If hands are visibly soiled, use soap and water. If not visibly soiled, use an alcohol-based hand rub or soap and water. Decontaminate hands before and after patient contact, rubbing hands together vigorously for 15 seconds then rinsing. The entire guideline is published on the CDC Web site at www.cdc.gov/handhygiene.7 It is recommended that patients wash their site arm carefully with soap and water when arriving at dialysis. Staff members who closely follow the policies and procedures of their respective facilities will always use and change gloves when indicated. It is important not to try to cannulate the same site with each treatment as this weakens the access wall.

The incidence of infection is higher in grafts than in AV fistulae. Dialysis catheters are also common sources of infection. In addition, the catheter can lead to a stenosis (blockage) of the central veins, threatening future arteriovenous access formation. Thus, it is important to have an AV fistula placed instead of a graft. Ideally, patients should have a fistula placed at least four months prior to starting their first hemodialysis.9

 References:

 NKF-K/DOQI Clinical Practice Guidelines for Vascular Access: update 2000. Am J Kidney Dis 2001; 37:S137-81.

 Ryan SV, Calligaro KD, Dougherty MJ. Management of hemodialysis access infections. Semin Vasc Surg 2004; 17:40-4.

 USRDS: the United States Renal Data System. Am J Kidney Dis 2003; 42:1-230.

 Minga TE, Flanagan KH, Allon M. Clinical consequences of infected arteriovenous grafts in hemodialysis patients. Am J Kidney Dis 2001; 38:975-8.

 Lew SQ, Kaveh K. Dialysis access related infections. Asaio J 2000; 46:S6-12.

 Ryan SV, Calligaro KD, Scharff J, Dougherty MJ. Management of infected prosthetic dialysis arteriovenous grafts. J Vasc Surg 2004; 39:73-8.

 Boyce JM, Pittet D. Guideline for Hand Hygiene in Health-Care Settings. Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Society for Healthcare Epidemiology of America/Association for Professionals in Infection Control/Infectious Diseases Society of America. MMWR Recomm Rep 2002; 51:1-45, quiz CE1-4.

 Piraino B. Staphylococcus aureus infections in dialysis patients: focus on prevention. Asaio J 2000; 46:S13-7.

Oliver MJ, Rothwell DM, Fung K, Hux JE, Lok CE. Late creation of vascular access for hemodialysis and increased risk of sepsis. J Am Soc Nephrol 2004; 15:1936-42.

Answer provided by Stephen Z. Fadem, MD, FACP who serves as a member of AAKP’s Medical Advisory Board and Vice President of the AAKP Board of Directors. Dr. Fadem is a practicing nephrologist in Houston, Texas. Dr. Fadem was assisted by Catherine Brown, PA-C, for this study. Ms. Brown is the clinical healthcare coordinator for Kidney Associates.

The Dear Doctor column provides readers with an opportunity to submit renal related health questions to healthcare professionals who specialize in the area of concern. The answers are not to be construed as a diagnosis and therefore, altercations in current healthcare should not occur until the patient's physician is consulted.

This article originally appeared in aakpRENALIFE, September 2004, Vol. 20 No. 2. 

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