An arteriovenous fistula (AVF) is a surgically created connection between an artery and a vein. This procedure provides long-term access for hemodialysis, a treatment that filters waste and excess fluid from the blood when kidneys fail.
Understanding Arteriovenous Fistulas
An AVF is a direct surgical connection between an artery and a vein, usually in the arm, though it can sometimes be placed in the leg. This connection allows high-pressure arterial blood to flow directly into a lower-pressure vein. The surge in blood flow and pressure causes the vein to enlarge and its walls to thicken, a process known as maturation.
This transformed vein becomes robust enough for repeated needle insertions during hemodialysis. An AVF is often chosen as vascular access for hemodialysis because it tends to last longer and has a lower risk of complications, such as infection or clotting, compared to other options like grafts or catheters. The increased blood flow through the vein ensures that sufficient blood volume can be processed during each dialysis treatment.
Preparing for AVF Placement
Preparation for AVF placement begins with a pre-operative evaluation. This includes a physical examination of your arms to assess blood vessel health, often using non-invasive tests like ultrasound to determine the suitability of arteries and veins for the fistula. Blood tests are also performed to check overall health.
Patients receive specific instructions before the procedure, including medication adjustments and fasting requirements. Arrangements for transportation home after the outpatient procedure should also be made.
The AVF Creation Procedure
AVF creation is a surgical procedure performed by a vascular specialist, often on an outpatient basis. It is commonly done under local or regional anesthesia to numb the area. Patients may feel some pressure but generally no pain during the procedure.
During surgery, a small incision is made, usually above the wrist or in the elbow crease, to access the chosen artery and vein. The surgeon connects them with sutures, forming an anastomosis. Once connected, blood flow is restored, and the incision is closed with sutures and a bandage. The process takes about an hour.
Post-Placement Care and Maturation
After AVF placement, care focuses on managing discomfort and protecting the surgical site. Patients may experience soreness and mild discharge for a few days. Keeping the access arm elevated helps reduce swelling and pain. Keep the incision clean and dry, and monitor for signs of infection like increased redness, swelling, warmth, or pus.
Maturation is the phase where the newly connected vein enlarges and strengthens for dialysis. This process takes several weeks to months before the fistula is ready for use. To aid maturation, patients perform gentle exercises, such as squeezing a rubber ball, to encourage blood flow and vein development. Avoid blood pressure cuffs, intravenous lines, or blood draws on the arm with the fistula to prevent damage. Regularly check for a “thrill” (a gentle vibration) and listen for a “bruit” (a whooshing sound) to monitor proper blood flow and successful maturation.
Potential Concerns with an AVF
While AVFs are durable, patients should be aware of potential concerns. Infection is a common issue, appearing as redness, warmth, swelling, or tenderness around the site. Another concern is thrombosis, or clotting, within the fistula, which blocks blood flow. This may be indicated by a loss of the thrill or bruit, or a cold, pale hand.
A less common but serious complication is “steal syndrome,” where the fistula diverts too much blood from the hand or fingers, leading to symptoms like coldness, numbness, pain, or weakness in the hand. If any of these signs or symptoms occur, contact a healthcare provider immediately. Prompt intervention addresses these issues and preserves AVF function.