Embolosclerotherapy: treatment of high-flow vascular malformations / arteriovenous malformations (AVMs)

What is a high-flow vascular malformation / AVM?

Vascular malformations are errors or abnormalities of blood vessels. These are usually a result of minor errors in the development of veins, arteries, or lymph vessels. They can occur anywhere in the body and can affect people in different ways. When the vascular malformation involves the arteries, it is known as a high-flow vascular malformation or arteriovenous malformation (AVMs).

What is embolosclerotherapy?

Under general anaesthetic (you will be asleep), a small access tube is inserted into an artery in the groin or the arm. Xray dye is then injected to outline the malformation. Under x-ray guidance, a chemical foam is then injected into the abnormal blood vessels. Sometimes metallic coils may be inserted to block the blood flow into the malformation. The treatment causes the malformations to become inflamed such that they shut down.

What are the benefits of this treatment?

Reduced pain, swelling and bleeding. It also potentially reduces the flow in the malformation.

What are the risks of this treatment?

After the injections, you can expect the treated area to be inflamed and sore. This can continue for two weeks or more and is expected. If required, paracetemol and ibuprofen can help with the pain (if it is safe for you to take these).

Minor complications that heal up following treatment may include:

• Bruising at the puncture site
• numbness or weakness near injection sites
• discoloration/ulceration to the overlying skin

These complications usually heal with time and, should they arise, you will be advised what to do by our team.

There is a small risk that the embolosclerotherapy agent (chemical foam, coils etc.) may be dislodged, moving to healthy tissue or organs, causing damage. This risk is reduced by having the procedure carried out under ultrasound and Xray visualisation.

There is also a small risk of injury to the artery where the access tube is placed. This can often be treated but sometimes needs surgery. Possible rare but serious complications will be discussed before treatment with a member of our team in the clinic.

What happens on the day?

• It is important that you arrive at the time specified on your appointment letter so that you can be seen by your healthcare professionals. Please note your treatment may not take place until later in the day.
• Please bring all your medication with you.
• Do not eat breakfast. You may drink water or tea (without milk or sugar) until 6am if you wish. When you arrive, the nurses will show you to your bed, check all your details and ask you to change into a hospital gown.

You will be visited by a doctor from the vascular malformation team who will explain the treatment to you again and ask you to read and sign a consent form. The doctor will be able to answer any questions you may have. You will also meet your anaesthetist. This is the doctor responsible for giving you your anaesthetic (medications used to send you to sleep so you don’t feel any pain or discomfort) during the procedure.

Will I need a general anaesthetic?

Yes. The injections can be quite painful if you are awake. It is also important that you are very still as the injections need to be very precise. If you have any questions about having a general anaesthetic, your anaesthetist will be able to answer these.

How long does the treatment take?

Usually, one to two hours plus the time it takes to anaesthetise you (put you to sleep) and wake you up once it’s finished.

After your procedure

You will be taken to the recovery area to be monitored until you are awake. You will then be taken back to the ward.

When you no longer feel drowsy, have passed urine, and have had something to eat or drink you will normally be free to go home. Please arrange for a friend or relative to collect you if possible. You could otherwise arrange patient transport or a taxi.

Can I continue as normal when I get home?

This depends on the individual, but we usually encourage you to be as mobile as possible. You will most likely have some discomfort and swelling in the treated area. This can continue for up to two weeks and is expected. If you can, take paracetamol and ibuprofen – this should be enough to control the pain. Please read the instructions on the medicines box or leaflet carefully before use. You may drive when you feel comfortable to do so safely.

When will I see my doctor again?

You will be sent an appointment to be seen in the vascular malformation clinic. This is usually about eight to ten weeks after your treatment.

This leaflet provides answers to common questions about embolosclerotherapy for treating high-flow vascular malformations. If you would like further information, or have any worries, please do not hesitate to ask your nurse or doctor.

In all cases, one of the vascular malformation team will explain the procedure to you and answer any questions you may have before you decide to have the procedure.