Understanding your dialysis access

When your kidneys stop working, dialysis does their job of cleaning waste, salt and extra water out of your blood. There are two kinds. In hemodialysis, your blood runs through a machine filter and back into your body, usually three times a week. In peritoneal dialysis (PD), fluid is placed inside your belly and the lining of the belly acts as the filter.

Either way, you need a reliable way in, called an access. For hemodialysis, the access must carry a lot of blood quickly, far more than a normal arm vein can handle. For PD, the access is a soft tube in your belly. Your access is often called your lifeline, because without it you cannot get dialysis.

Interventional radiologists are doctors who use X-ray and ultrasound to treat problems from the inside, through small punctures. We place catheters, create some fistulas without surgery, and repair accesses that are narrowed or clotted. If you are new to our specialty, see what is interventional radiology.

On a fistulogram, contrast dye makes the fistula show up as a wide dark channel running up the arm from the artery connection toward the shoulder, so narrow spots stand out as a waist in the channel.

A fistula has traditionally been made by a surgeon through an incision at the wrist or elbow. A newer option, the percutaneous AV fistula (pAVF), creates the connection from inside the blood vessels, through needle punctures near the elbow. There is no open incision and no stitches, and it usually takes about an hour under sedation and local numbing.

The doctor uses ultrasound and X-ray to guide thin catheters into a deep artery and vein that lie side by side below the elbow, then uses a small burst of heat energy to join them. Blood then flows into the arm veins through a natural connecting vein. Like a surgical fistula, it still needs time to mature, usually about 6–12 weeks, and some people need a balloon treatment afterward to help it grow.

A surgical fistula is still an excellent choice and is the right option for many people. An ultrasound map of your arm veins and arteries tells us which approach fits your anatomy.

A working fistula or graft has a steady flow of blood you can feel and hear. Checking it every morning and evening takes less than a minute and is the best way to catch a problem early, while it can still be fixed with a small procedure.

If you have chronic kidney disease but are not on dialysis yet, protect your arm veins for a future fistula. Ask that blood draws come from the back of the hand when possible, and avoid a PICC line if another option exists. See PICC lines.

A lost thrill usually means the access has clotted. This is common and often fixable, but it needs a quick response so you do not miss dialysis. See clotted dialysis access. Slower changes, such as a weaker thrill or long bleeding, often point to a narrowing that can be opened with a balloon during a fistulogram.

A fistula or graft pulls blood toward the vein. In a small number of people, it pulls so much that the hand beyond it does not get enough blood. This is called dialysis access steal syndrome. It is more likely if you have diabetes, hardened arteries, or an access near the elbow.

Mild coldness is common in the first weeks and often improves. Pain at rest, weakness, or finger sores are serious and need to be seen within a day, because the nerves and tissue of the hand can be damaged. Treatment depends on the cause. We may open a narrowed artery with a balloon, or a surgeon may adjust the access to reduce its flow. The goal is to protect your hand and keep your access when possible.

Most access problems come from a stenosis, a narrow segment where scar tissue builds up inside the vein, often near the artery connection or where the graft joins the vein. Narrowing slows the flow and eventually leads to clotting. Other problems include infection, bulging (aneurysm), and narrowing of the large veins in the chest, which causes arm swelling.

I think of every access as something worth saving, because each one uses up veins you cannot get back. When I look at a fistulogram, I follow the dye from the artery all the way to the heart, since the narrowing that matters is sometimes far from where the needles go. I tell patients that the daily thrill check is the most useful thing they can do: a weak buzz caught on Monday is a 45-minute outpatient fix, while a clot found on Friday can mean a missed treatment.

Fabio Komlos, MD, interventional radiologist · About Dr. Fabio Komlos