Dialysis, also called hemodialysis, is the most common treatment for kidney failure. A dialysis machine is an artificial kidney designed to remove impurities from your blood.

Your physician will first create an access portal, an entranceway into your bloodstream that lies beneath your skin and is easy to use. The access is usually in your arm or leg and allows blood to be removed and returned quickly, efficiently, and safely during dialysis or, less commonly, for other procedures requiring frequent access to your circulation.

During dialysis, physicians use the dialysis access portal to circulate your blood through the machine to remove impurities and regulate fluid and chemical balances. The purified blood is then returned to you again through the dialysis access.

Types of Dialysis Access Procedures
Creating the access portal is a minor surgical procedure. There are two types of portals:

Fistula, which your vascular surgeon constructs by joining an artery to a vein
Graft, which is a man-made tube that your vascular surgeon inserts to connect an artery to a vein
Fistulas are typically preferred to grafts because fistulas are constructed using your own tissue, which is more durable and resistant to infection than graft. However, if your vein is blocked or too small to use, the graft provides a good alternative.

For both fistulas and grafts, the connection between your artery and vein increases blood flow through the vein. In response, your vein stretches and becomes strengthened. This allows an even greater amount of blood to pass through the vein and allows your dialysis to proceed efficiently.

In the weeks after surgery, the fistula begins to mature. The vein increases in size and may look like a cord under your skin. The whole process typically takes 3 to 6 months. Some fistulas may take as long as a year or more to develop fully, but this is unusual.

Once matured, a fistula should be large and strong enough for dialysis technicians and nurses to insert the large dialysis needles easily. If it fails to mature in a reasonable period of time, you may need another fistula.

If you had a graft instead, you can usually begin using your graft in 2 to 6 weeks, when it is healed sufficiently.