Risks of delayed treatment, fistula failure, and infection part of debate
Challenges associated with arteriovenous (AV) fistulas for patients requiring hemodialysis trigger debate among nephrologists about whether a surgical graft should be considered for some patients as the initial hemodialysis access to accelerate care, limit fistula failure, and reduce bacteremia risk by eliminating catheter use.
Because of their durability and high blood flow volume, fistulas are generally preferred for patients who require hemodialysis. But fistulas mature slowly, and the process may delay the beginning of treatment. Maturation filure associated with fistulas often requires patients to shift to long-term catheter use.
Duke nephrologist Eugene C. Kovalik MD, a hemodialysis specialist, provided answers to common questions to inform the discussion about fistulas versus surgical grafts and/or catheters.
Question: What are the major concerns about AV fistulas in the daily practice of hemodialysis?
Kovalik: Vascular access is obviously the lifeline for patients who need hemodialysis. We should be continually assessing their utility and looking at possible improvements. While fistulas are generally preferred, 30 percent fail to mature and result in delays for treatment of patients. Even when they mature correctly, the process may require months and various interventions. This typically occurs when we need to begin dialysis as soon as possible. Also, fistula maturation failures result in the placement of catheters for long-term use, which introduces inherent risks, notably repeated infection.
Question: Are specific groups of patients more at-risk for AV fistula failure?
Kovalik: The failure rate is higher for two groups of patients: Women, who have smaller veins and are more susceptible to problems, as well as patients with diabetes.
Question: Other than insertion of catheters, what alternatives for fistulas do you see in practice?
Kovalik: Synthetic graft materials such as GORE-TEX vascular grafts (Gore Medical Products Division, Flagstaff, AZ), have become an effective alternative access device that can be used within three to four weeks of placement. These grafts have a higher infection rate than fistulas, but it is still much lower than what we experience with catheters. Grafts come with challenges as well. They may also require multiple procedures to keep them open due to the increased risk for thrombosis from intimal hyperplasia.
Question: Do you see new techniques or options that present more effective solutions for either AV fistulas or grafts?
Kovalik: Grafts placed in the forearm position can contribute to the maturation of veins further downstream. These downstream veins can then be later used to create a fistula. It’s an option we consider in some cases.