The importance of a good vascular access to enable successful dialysis, with the most effective and durable type of vascular access being a fistula. So why is vascular access such an important topic, It’s because studies in the literature show that patients on dialysis with a successful well-functioning fistula do better in the long term than those patients dialysing with a catheter, (also known as a line).

So whenever possible we always try to create an effective fistula for anyone on dialysis. There are some exceptions, for example patients who are frail or who have heart failure, and those that don’t have good blood vessels to make a fistula will often have a line. A line can be used to bridge a gap, for example between starting dialysis and having a live donor transplant when there is a short time span between these two points.

The two major complications of a line don’t occur with a fistula. These are infection which can sometimes be life-threatening and narrowing of the central veins leading to the heart. Not only do these two complications not occur with a fistula but also from a lifestyle perspective, a fistula doesn’t involve plastic lines sticking out of your chest wall, and therefore bathing, showering, swimming, walking on the beach, all these things are so much easier with a fistula. A fistula usually takes about six weeks to ‘mature’ and at this point it is ready to be ‘needled’ for dialysis. The first few sessions of dialysis with a new fistula can be a little tricky with some bruising but normally this settles down

With time you will be able to feel your fistula and be able to tell whether there are any changes to how powerful it is and whether it is possibly getting bigger in size. Normally a good functioning fistula has a ‘buzz’ that you can feel; it is also called a ‘thrill’. This is the fast-flowing blood travelling back up the vein and can sometimes feel like an electric buzzing. As the fistula matures, there are reasons why this ‘buzz’ might change to a more pulse-like thrill. This is important to appreciate as it might signify that there is a narrowing as the fistula travels up the arm round the shoulder and into the great veins. If this happens, when the needles are taken out of the fistula after your dialysis session, there might be more bleeding than normal.

This is called decannulation bleeding. If this happens you and your dialysis nurse can notify your surgeon and investigations can be done to work out what is going on. The most common investigation for a fistula is called a ‘duplex’

This is quite a straightforward investigation involving ultrasound; a vascular scientist examines the blood flow in your fistula and works out whether there are any areas of narrowing or ‘stenosis’. Occasionally where there are areas of stenosis, a ‘fistuloplasty’ can be performed. This is where an interventional radiologist under x-ray guidance can expand a balloon in a narrowing in the fistula to re-establish normal flow and with the hope that the buzz will reappear.

How the fistula is needled is very important. The best way of needling is described as a ‘rope ladder’ technique. This is where the needle is inserted at different levels each dialysis session. If one area of a fistula is repeatedly needled, this leads to aneurysmal formation. This is the term used to describe a swelling of the fistula which can lead to problems. So always try and make sure that your fistula is being needled all the way along its length rather than just one or two places.

Every so often a fistula will stop working. This is called a thrombosis and the fistula will become full of clotted blood instead of flowing blood. If this happens it needs immediate attention. The signs to look out for would be no flow in the fistula (the buzz would disappear) and possibly pain and redness over the fistula. If this happens and your dialysis nurse spots this, he or she will refer you to the local fistula surgical department as an emergency. If you notice this whilst at home, you should pitch up to your local renal department as soon as you can.

A thrombosed fistula can be rescued by an operation called de-clotting. But time is of the essence, and this should ideally happen within 24 to 48 hours. There are different reasons as to why a fistula thromboses, sometimes it’s due to narrowing as discussed but also it could be due to dehydration, for example after having a bout of diarrhoea or being generally unwell. It stands to reason why rates of thrombosed fistulas can increase when the weather is really hot such as last summer and patients are becoming dehydrated.

Uncommonly, a fistula can bleed. This is often from a needling site where there is a weakness on the skin surface of the fistula. If this happens the most important thing to do is to put pressure on the spot where it is bleeding from. A bottle top is a great device to put on the bleeding point but anything will do.

The next thing is to urgently call 999 as you might need an operation to stop the bleeding and prevent it happening in the future. The integrity of the skin over the fistula, is crucial, so if there are any new skin changes or scabs over the fistula you should ask your health professional to take a look. A fistula is a precious lifeline for a patient on dialysis. I hope this article sheds more light on how to look after your fistula and what to look out for.

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Written by Jeremy Crane MD FRCS (vasc)
Consultant transplant and vascular surgeon at the Hammersmith Hospital West London.

Information from an article from Kidney Life Magazine Spring 2023