The AV fistula (=shunt) is the most common and also preferred vascular access for hemodialysis.
As already described in another article, you need an easily accessible and functioning vascular access for dialysis treatment. In hemodialysis, you need this to be able to direct blood into the dialyzer and clean it there. Proper vascular access offers therapy safety, well-being and, above all, dialysis without complications.
The AV fistula is the preferred vascular access for hemodialysis.
As already mentioned, the AV fistula is the first choice. The fistula, also called a shunt, is a surgical connection between an artery and a vein. This is done to allow a sufficiently strong blood flow in the vein for therapy.
Deal with your vascular access at an early stage
It is advisable to start planning a shunt for dialysis early. What does early mean in this context? There are guidelines that say that vascular access should be started as early as a glomerular filtration rate below 30. In practice, this is often very early. However, it can still make sense if the vascular conditions are difficult.
However, the AV fistula should be created at least 3 months before the start of dialysis. The main reason for this is that the shunt cannot be used immediately after the operation. It needs an "acclimatization phase".
What determines a good shunt?
After a successful shunt operation, an AV fistula must meet the following requirements:
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A blood flow of at least 300 ml per minute.
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All parts of the body should be sufficiently supplied with blood - also after shunt surgery.
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The heart should also not be put under additional strain as a result.
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The blood vessels that affect the AV fistula should not have any constrictions.
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The part of the body where the shunt is located should not have any problems or nerve damage.
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The AV fistula should be good and easy to puncture.
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It should also be possible to apply some pressure later on. After each dialysis, you will be asked to apply gentle pressure on the shunt until it stops bleeding. This also means that you should be able to reach it with your hand.
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The AV fistula should not be placed deeper than 0.6 cm under the skin.
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In addition, a well-applied fistula should only be faintly visible and should hinder you as little as possible during daily activities.
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If the shunt is on your arm, it is more practical for right-handed people to have it on their left arm (and vice versa, of course).
What is the procedure for a shunt operation (shunt surgery)?
Your nephrologist will refer you to a vascular surgeon. They will check how well your blood vessels still function. On this basis, they will determine the best place for your AV fistula, according to the criteria just described. The ideal case is a shunt on the forearm, but it is also possible that it is placed in the crook of the arm or on your upper arm. Very rarely, a shunt may be placed on the thigh.
The operation is usually done with a local anaesthetic. This means that you will not be given a general anaesthetic. After the intervention, you can normally go straight home. Afterwards you may have a few follow-up appointments. In some cases, your nephrologist will give you medications to make sure that the shunt operation is successful.
What happens after shunt surgery?
After surgery, there are a few things you should keep in mind. For example, you should take it easy on your arm for now, while avoiding low blood pressure. Typically, you'll be given a squeeze ball to ensure that. Training with it, will ensure that the blood flow in your shunt is also strengthened. Blood pressure should not be taken at the site of the shunt to avoid any problems. The surgical stitches are removed on the 10th-12th day after the operation.
How can I recognize a healthy shunt?
You can tell a healthy shunt by the way it "buzzes." This may be annoying at first, but you'll get used to it. You can check if everything is okay by feeling it or listening to it. You should feel it at least once a day so that you can detect problems early.
Bulge-like bumps, also called aneurysms, can also form on your shunt arm. If this happens to you, it is best to discuss it with your nephrologist. In the long-term, relatively many dialysis patients have these aneurysms.
What happens when my shunt stops humming?
If you experience pain at the shunt or if the shunt no longer "buzzes", contact your dialysis center immediately. Also, if you develop numbness in the shunt arm or in the hand of your shunt arm, it is best to contact your dialysis center.
