Arteriovenous fistula: what it is and how surgery works

An arteriovenous fistula is a surgical connection between an artery and a vein, usually in the arm, so that the vein becomes wide enough and carries enough blood flow for haemodialysis. For most people who will be on haemodialysis for a long time, it is the access with the lowest risk of infection and the longest lifespan. The surgery is usually done under local anaesthesia or an arm block, and the fistula generally takes 6 to 8 weeks to be ready for use.

What an arteriovenous fistula is

In haemodialysis sessions, blood leaves the body, passes through a filter and returns, usually three times a week. The process needs a high flow: ordinary arm veins are too thin for this, and repeatedly puncturing arteries is not safe.

In a fistula, the surgeon joins a superficial vein to a nearby artery. With arterial blood flowing through it at high pressure and speed, the vein widens and its wall thickens, a process called maturation. Once mature, the vein can be easily reached and safely needled at every session.

When you place your hand over the fistula, you feel a continuous buzzing, the thrill. It is the sign that the fistula is working.

In a fistula, part of the blood in the artery flows straight into the vein. The vein widens and receives the two dialysis needles: one takes blood to the machine and the other brings it back.

Fistula, graft or catheter: what is the difference

Access	What it is	Advantages	Limitations
Arteriovenous fistula	Your own artery joined to your own vein	Lower risk of infection and longer lifespan once mature	Needs weeks to mature, and this does not always happen
Graft	A synthetic tube under the skin that connects an artery and a vein	Can be used sooner, usually after 2 to 4 weeks; some models within a few days	More stenoses (narrowings) and thromboses, and a higher risk of infection than a fistula
Central venous catheter	A tube in a large vein in the neck or chest	Immediate use	Higher risk of infection and of stenosis (narrowing) of the central veins; best as a temporary solution

Current guidelines do not treat the fistula as a rule for everyone. The choice takes into account each person's veins and arteries, age, other conditions, the expected time on dialysis and the possibility of a transplant. The American guideline calls this an end-stage kidney disease life-plan. Even so, for most people with good veins who are about to start haemodialysis, the fistula remains the first choice.

In Brazil, around 172,000 people were on dialysis in July 2024, and almost a quarter of patients were using a long-term catheter, according to the Brazilian Dialysis Survey. Planning the fistula ahead of time is what makes it possible to avoid a catheter or shorten the time on one.

When to have the fistula made

Ideally, the fistula is created before haemodialysis starts, so that it has time to mature. The nephrologist usually refers the patient to the vascular surgeon when kidney disease is advanced and dialysis is expected within the following months. This is not always possible when haemodialysis starts as an emergency.

People already on haemodialysis through a catheter can also have a fistula made and, whenever possible, should, so that the catheter can later be removed.

Doppler mapping before surgery

Before surgery, a Doppler ultrasound assesses the diameter and quality of the veins and arteries in both arms. This scan defines the best site for the fistula and increases the chance that it will mature. That is why guidelines recommend mapping before every fistula. In the clinic, the Doppler scan is done during the consultation itself.

The non-dominant arm and the site closest to the wrist that is suitable are usually preferred. This keeps the veins further up the arm available for future access.

Most common types of fistula

A fistula can be made in several places; the most common are the wrist, the elbow and the upper arm. Starting as close to the hand as possible preserves the veins further up for future access.

Radiocephalic (at the wrist or forearm): joins the radial artery to the cephalic vein. It is usually the first choice when the forearm vessels are suitable.
Brachiocephalic (just below the elbow crease): joins the brachial artery to the cephalic vein, or the median vein, just below the elbow crease. It generally has higher flow and matures more often than a wrist fistula.
Brachiobasilic: created in the lower third of the upper arm. It can be done with transposition, with a second incision near the armpit and a slightly longer operation, or the basilic vein, which lies deep in the arm, can be brought closer to the skin in a second operation so that it can be needled.

How the surgery works

It is done in the operating theatre, usually under local anaesthesia or an arm block (brachial plexus block), sometimes with light sedation.
The incision is small, and the surgery usually takes about 30 minutes, depending on the type of fistula and on the surgeon's experience and skill.
In most cases, you go home the same day.
The usual course is to arrive at the hospital or clinic fasting, have the procedure as a day case under local anaesthesia and go home shortly after surgery, provided there are no complications.

The process and how long the fistula takes to mature

Before surgery: Doppler mappingDefines the best site for the fistula.
SurgeryThe artery is joined to the vein, usually in about 30 minutes.
MaturationUsually 6 to 8 weeks: the vein widens and its wall thickens.
AssessmentPhysical examination and Doppler confirm that the fistula is ready.
Use for haemodialysisNeedling moves to the fistula, and the catheter, if there is one, can be removed after a few sessions using the fistula.

So the whole process usually takes about 2 months. The fistula is ready when the vein has enough diameter and flow and lies close enough to the surface to be needled safely. This is confirmed by physical examination and Doppler.

Not every fistula matures. When this happens, there is often a treatable cause, such as a stenosis (narrowing) or vein branches that divert the flow. These causes can be corrected with angioplasty (opening the narrowing with a small balloon) or with minor surgery.

After the fistula is made, hand exercises, such as squeezing a ball, are often recommended. Their effect on maturation is modest, but they are a simple and safe measure.

Looking after the fistula arm

Day to day

Feel the thrill every day, morning and evening.
Do not allow blood pressure measurements, blood tests or drips on that arm. Only the dialysis team should needle the fistula.
Avoid watches, bracelets, tight clothing and sleeping on the fistula arm.
Do not carry heavy loads with that arm in the first few weeks.
Wash the arm every day with clean running water and mild soap.
Look after your blood pressure. High blood pressure should be treated, but episodes of low blood pressure can also cause the fistula to clot because of low flow.

Seek care the same day if

the thrill stops or becomes much weaker;
the hand becomes cold, pale, bluish, numb or very painful;
there is redness, warmth, discharge or fever;
there is bleeding that does not stop with pressure;
the arm swells a lot or the skin over the fistula becomes thin, shiny or broken.

A fistula that has stopped working can often be rescued. The sooner it is treated, the better the chance.

Possible complications

The most common are failure to mature, bruising (haematomas), stenoses (narrowings) and occlusion (fistula thrombosis). Less common are steal syndrome, in which the fistula diverts blood away from the hand and causes coldness, pain, numbness or wounds, aneurysms along the needling sites, excessive flow, which can overload the heart, and infections. Most can be treated, with surgery or with a catheter procedure (angioplasty). Regular follow-up helps to find problems before the fistula stops working.

Frequently asked questions

Does fistula surgery hurt?

With local anaesthesia or an arm block, the surgery should not hurt. Afterwards, the pain is usually mild and controlled with simple painkillers.

When can I start using the fistula?

Only after it has matured, usually between 6 and 8 weeks, and after assessment by the surgeon or the dialysis team. Needling too early increases the risk of bruising and of losing the fistula.

Can I shower after the surgery?

Yes. Follow the advice given when you go home: in general, the dressing should be kept clean and dry until the stitches are removed. You can wash the wound with clean water or saline and mild soap, or use a waterproof dressing in the shower. Sprays, gels and ointments are usually not needed.

Can I sleep on the fistula arm?

It is best to avoid it. Sleeping on the arm can compress the fistula and lead to thrombosis.

Can people with a fistula exercise?

Yes. Physical activity is recommended. But avoid knocks, such as those in contact sports, and pressure on that arm, especially in the first few weeks.

Does the fistula need to be closed after a transplant?

Not necessarily. Many people keep their fistula after a transplant. The decision to close it is individual and made with the nephrologist and the vascular surgeon.

References

Lok CE, Huber TS, Lee T, et al. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis. 2020;75(4 Suppl 2):S1–S164. doi:10.1053/j.ajkd.2019.12.001
Schmidli J, Widmer MK, Basile C, et al. Vascular Access: 2018 Clinical Practice Guidelines of the European Society for Vascular Surgery (ESVS). Eur J Vasc Endovasc Surg. 2018;55(6):757–818. doi:10.1016/j.ejvs.2018.02.001
Nerbass FB, Lima HN, Zawadzki B, Moura-Neto JA, Lugon JR, Sesso R. Brazilian Dialysis Survey 2024. Braz J Nephrol. 2026;48(1). doi:10.1590/2175-8239-JBN-2025-0112en

Arteriovenous fistula: what it is and how the surgery works