Overview

This information is about a procedure called a fistula thrombectomy. It involves clearing a blood clot (thrombus) from inside an artery or vein.

A fistula is a connection between an artery and a vein. Joining an artery and a vein together makes a blood vessel larger and stronger. This makes it easier for us to transfer your blood into a machine and back again if you have dialysis. 

Dialysis is a treatment to remove waste products and too much fluid from the blood if your kidneys stop working properly. It often involves transferring blood into a machine to be cleaned.

The aim of this information is to answer your questions about having a fistula thrombectomy to remove a blood clot from a fistula. It explains:

• the benefits of the procedure
• the risks of the procedure
• what you can expect when you come to hospital
• what happens after the procedure

If you have any more questions or concerns, please contact the interventional radiology (IR) department.

About a fistula thrombectomy

If you get a blood clot in a fistula, we:

• remove the blood clot using a special device to break it up and suck it out
• sometimes give you a medicine called alteplase (also called tPA) to help dissolve the blood clot

When most of the blood clot has been cleared, we need to treat any narrowings that may have caused the clotting. We inflate a balloon inside the fistula to stretch the narrowings open. This process is called a fistuloplasty. Sometimes, we may put in a tiny metal tube called a stent to keep the narrowings open.

We can do the procedure on:

• a blood vessel called an arteriovenous fistula (AV fistula), which is created by connecting an artery to a vein
• an AV graft, which is when we use a piece of man-made tubing to connect the artery to the vein (if your blood vessels are too narrow to create an AV fistula)

What interventional radiologists do

A specialist doctor called an interventional radiologist (IR doctor) does the procedure in an operating theatre.

IR doctors do minimally invasive operations using guidance from images, such as X-rays and ultrasound scans. They do most procedures through very small cuts in the skin that are often less than 1cm long. 

As part of this procedure, the IR doctor uses ultrasound and X-rays with a substance called a contrast agent. The contrast agent shows clearly on the X-rays. This helps the IR doctor to find the blood vessels and the position of the blood clot.

Benefits of the procedure

We recommend a fistula thrombectomy when a fistula is blocked with a blood clot. For dialysis to work well, blood needs to flow through your fistula easily.

Narrowings in the fistula are common due to several factors, such as regularly having a needle put in for dialysis. These narrowings can:

• reduce blood flow
• cause blood clots within the fistula

You can often tell if your fistula has a blood clot because it feels hard and does not pulse or buzz anymore. Your doctor has referred you to the interventional radiology (IR) department to try to get your fistula working again.

Risks of the procedure

We do fistula thrombectomy procedures regularly. Serious risks and complications are uncommon, but you need to be aware of them.

The IR doctor explains the risks clearly before you sign a consent form agreeing to have the procedure. Please ask any questions that you have.

The risks are different for each person, but the most common are listed in this section.

Significant bleeding

The medicine used to clear the blood clot slightly increases your chances of unwanted bleeding elsewhere in the body. This is most significant in the brain. The IR doctor needs to assess your individual risk of bleeding.

Bleeding may also happen if the fistula is accidentally damaged during the procedure. In this case, the IR doctor usually treats the bleeding immediately.

Sometimes, the problem with your fistula is due to narrowing of a vein in the chest. We would also treat this narrowing by stretching it with a balloon. If there is an injury during the procedure, the bleeding can be very serious. The IR doctor can usually treat this immediately but in some cases, we need to do emergency surgery.

Bruising

You get a small bruise around the skin cut over the fistula. This is to be expected and usually disappears within a few weeks.

In rare cases, the bruise may become large and uncomfortable. If you get a large bruise, you may need to stay in hospital overnight while we monitor you. Usually, the bruising settles with pressure from the hands (manual pressure) only.

Infection

There is a small risk of getting an infection. This would need treatment with antibiotics or surgery, but is a very rare complication.

Allergic reaction

Some people may have an allergic reaction to the contrast agent that is used to make the blood vessels show on the X-ray pictures. This is usually a small (minor) reaction, such as a skin rash, and does not often need treatment. 

In rare cases, an allergic reaction can be more serious and needs to be treated with anti-inflammatory medicines called steroids.

Treatment not working

There is a small risk that the treatment might not work. If this happens, your doctor will talk to you about other treatment options.

Radiation risks

During a fistula thrombectomy procedure, you are exposed to X-rays. They are a type of radiation called ionising radiation. This may cause cancer many years or decades after you are exposed to it.

You might have some skin redness after the procedure that feels like sunburn. We do not expect this to be permanent. The redness might be harder to notice on brown and black skin. 

Interventional radiology (IR) is when we use medical imaging guidance to do minimally invasive procedures. The amount (dose) of radiation from these procedures is generally low. More complex procedures might involve a medium (moderate) dose of radiation.

The IR doctor and radiographer (health professional who specialises in medical imaging) make sure that:

• your radiation dose is kept as low as possible
• the benefits of having X-rays during your procedure are greater than the radiation risks

Radiation and pregnancy

Radiation can be harmful for an unborn baby. If you are or think that you might be pregnant, it is important to tell a member of your medical team before the procedure. We cannot do any procedure that involves radiation if you are pregnant.
 
If you can become pregnant from sex, you need to use protection (contraception) from the first day of your period until your appointment. This means that you will not be pregnant when you have the procedure.

If the first day of your period has already passed, please contact the interventional radiology (IR) department. We can then give you another appointment within the first 10 days of your period. 

We ask you to sign a pregnancy declaration form before the procedure.

Other treatment options

The doctors who you see for dialysis may decide to abandon the blocked fistula. This may be the most suitable option if:

• the fistula has become blocked several times recently
• is unlikely to stay open for long

This means that you will need:

• a new dialysis line to be put in
• an operation to make a new fistula

We rarely use open surgery (which involves cutting the skin and tissues) to remove a blood clot and preserve the fistula.