Patients with kidney failure need dialysis to remove impurities from their blood and help balance the fluid and electrolyte levels in the body. The most common method of doing this is by using a dialysis machine (hemodialysis) to filter the blood and return it to the body. In order to allow for hemodialysis, a fistula is created, wherein a vein is joined onto an artery, thus creating an AV (arteriovenous) fistula. After being joined to the artery, because of the higher pressure and faster blood flow, the vein slowly enlarges and develops a thicker stronger wall.
This maturation process takes usually a minimum of 6 weeks and sometimes upto 3 months. Once a fistula is deemed ready to use, it then allows for 2 needles to be placed in the vein so hemodialysis can be performed. The fistula surgery is usually performed either at the wrist or the elbow and may require some pre-operative scans in order to decide where the best place to make a fistula would be. A fistula can be made either directly joining a vein onto the artery or by using a synthetic graft to form a connection between artery and vein. Occasionally after surgery, the fistula may not mature as expected for a number of reasons. This may mean that the fistula is at risk of blocking or not being good enough to use for dialysis. In these situations, additional procedures may be required (angioplasty or more surgery) to allow maturation of the fistula.