Dialysis is a procedure that is required in patients with kidney failure for purification of toxins from blood which was originally the function of kidneys. When the kidneys fail, there is less urine output and therefore toxins are not removed from body. Once the diagnosis of chronic (end stage) kidney disease is made, patient is advised dialysis. The longest-lasting and best type of dialysis access is an arteriovenous fistula, or AV fistula.

For this, a dialysis machine is used which draws impure blood from patient body, purifies it outside the body and then it is reverted back to the patient body. This requires two lines of intravascular access in the patient. Arteriovenous fistula is made for the purpose of easing the dialysis for both patient and the technician. In this, a vein and an artery are joined together to facilitate the drawing of blood by the machine and its transfer back into the body. If fistula is not made, technician has to introduce two intravenous cannulae in the patient, one venous and one arterial which is more painful to patient and require skilled technician.

Arteriovenous fistula creates the access point in the body for the dialysis machine. One artery and one vein is joined together by a microvascular surgeon under magnification of microscope.

It is commonly created at the left wrist. Other sites can be elbow, right wrist and arm region

Normal blood flow in the artery of arm is 85 to 110 milliliters per minute (mL/min). After the creation of a fistula, the blood flow increases to 400–500 mL/min immediately, and 700–1,000 mL/min within 1 month. Fistula at the elbow carries more amount of blood than fistula at wrist.