An arteriovenous (AV) fistula is a specialized connection created to facilitate medical treatments. It provides a reliable and durable access point for ongoing medical interventions.
What an AV Fistula Is
An arteriovenous (AV) fistula is a direct surgical connection between an artery and a vein, typically located in the arm. Arteries are blood vessels responsible for carrying oxygen-rich blood away from the heart to the body’s tissues. Conversely, veins are the vessels that return deoxygenated blood from the body back to the heart. This alteration transforms the vein, preparing it for a specific medical purpose. The connected vein begins to undergo changes due to the increased blood pressure and flow it receives from the artery.
Purpose and Creation
The purpose of an AV fistula is to provide a robust, long-lasting access site for hemodialysis in individuals with kidney failure. When kidneys can no longer adequately filter waste products from the blood, hemodialysis becomes a necessary treatment. This process requires repeated access to a blood vessel capable of handling high volumes of blood flow for efficient filtration.
The creation of an AV fistula involves a surgical procedure, often outpatient. During the operation, a surgeon connects an artery to a neighboring vein, usually in the forearm or upper arm. This connection can be made either end-to-side, where the end of the vein is sewn to the side of the artery, or side-to-side, connecting the sides of both vessels.
How It Works
After surgical creation, an AV fistula requires a period of “maturation” before it can be effectively used. This maturation process involves the vein adapting to the higher pressure and increased volume of blood flowing directly from the artery. Over several weeks to months, the vein enlarges in diameter and its walls thicken, becoming stronger and more resilient.
A mature fistula becomes a prominent, palpable vessel beneath the skin, suitable for repeated needle insertions required during hemodialysis sessions. Increased blood flow within the matured vein allows for efficient withdrawal and return of blood during the dialysis process. This robust access minimizes complications often associated with other types of dialysis access, such as catheters.
Patient Care and Considerations
Proper care of an AV fistula is important for its longevity and to prevent complications. Individuals with a fistula should regularly inspect the site for any signs of infection, such as redness, swelling, warmth, or discharge. Patients should feel for a “thrill” (a subtle vibration) or listen for a “bruit” (a whooshing sound), both indicating proper blood flow.
Protecting the fistula arm from injury and undue pressure is important. Avoid wearing tight clothing or jewelry on the fistula arm. Blood pressure measurements and intravenous injections should not be performed on the arm containing the fistula, as these actions can compromise its integrity. Regular follow-up appointments with healthcare providers are important to monitor the fistula’s function and address any potential issues promptly.