What is an AV fistula?
The AV fistula is created by making a surgical anastomosis between an artery in the forearm or upper arm with an adjacent vein.
Over a period of 4 to 8 weeks, the increased pressure that the vein is exposed to from the arterial bed causes the vein to dilate and develop a thicker vessel wall. Once the fistula has matured—defined as a blood flow rate of at least 600 mL/min and a diameter of at least 6 mm—the fistula can be cannulated with dialysis needles to allow for the removal and return of blood.
Typically, 15-gauge needles are used as dialysis needles, although smaller needles may be used at first if the fistula is not fully mature.
