Angiomyolipoma (AML) Embolisation

An angiomyolipoma (AML) is a non-cancerous (benign) growth that can develop in the kidney. It is made up of three types of tissue: fat (lipoma), muscle (myoma), and abnormal blood vessels (angioma).

If an AML grows large, it can sometimes cause problems. These include a higher risk of bleeding from the abnormal blood vessels, or pressure on nearby structures in the kidney that may cause pain or other symptoms.

Embolisation is a treatment that works by blocking the blood supply to the AML. This can help shrink the growth or prevent it from getting bigger. The procedure is done by passing a thin plastic tube (catheter) into an artery in the leg or wrist and carefully guiding it into the blood vessels that feed the AML. Once in the right place, special materials are injected to block these vessels. These may include tiny particles or beads, glue, metal coils or alcohol. By cutting off the blood flow, the risk of future bleeding from the AML is reduced or eliminated and it also usually reduces significantly in size.

Why alcohol?

In some cases, a special medical alcohol (absolute ethanol) is used to block the blood supply to the angiomyolipoma. This is not the same as drinking alcohol.

Alcohol is very effective because it can reach and close off even the tiniest abnormal blood vessels within the tumour. This helps make the treatment more complete and reduces the chance of the angiomyolipoma bleeding.

Because alcohol is so strong, it is only used when doctors feel it is the safest and most effective option for you. It is delivered very precisely through the catheter to limit any effect on the rest of the kidney.

Embolisation is a well-established and effective treatment for angiomyolipomas. In most cases, it successfully reduces the risk of bleeding and can shrink the size of the growth. While surgery is also sometimes used to treat AMLs, embolisation is a much less invasive procedure, with shorter recovery times and lower risk of complications.

Studies show that embolisation controls bleeding in over 90% of patients and often reduces the size of an AML by 30–50% or more. In our practice at UCLH, we see a mean reduction of 38% in AML size at 12 months. Many people also notice an improvement in symptoms such as pain or pressure.

However, AMLs can sometimes grow again, or new ones can develop. In these cases, a repeat embolisation or another type of treatment may be needed.

Your doctor will arrange follow-up scans to check the effect of the treatment and to make sure the AML remains under control.

There are different treatment options for AMLs. The best approach depends on the size of the lesion, your symptoms, and your overall health. Your case has been considered by a team of Surgeons, Urologists, and Interventional Radiologists (IR), who feel that embolisation is a suitable option for you.

Surgery

This usually involves removal of the tumour and part of the kidney (partial nephrectomy). In rare cases, if the AML is very large or complex, the whole kidney might need to be removed (nephrectomy).

Observation (“Watch and Wait”)

If the AML is small and not causing any problems, it may be safe to simply monitor it with regular scans. This allows doctors to check for any growth or changes over time before deciding if any active treatment is needed.

Please do not hesitate to ask if you have any further questions about the alternative treatment strategies.

Embolisation is generally a safe and well-tolerated procedure. However, as with any medical treatment, there are some risks and possible complications. We take all precautionary measures to minimise these and to ensure that the procedure is appropriate for you.

Immediate risks

Bleeding: Small risk (<5%) of significant bleeding from the puncture site in the groin or wrist where the catheter is inserted. You are monitored closely during and after the procedure and if any significant bleeding is suspected, we may do a CT or US scan to evaluate further. Rarely, a further procedure may be needed to stop the bleeding.

Occlusion: The puncture site in the artery is often sealed using a closure device. Very rarely (<0.5%), this may block the artery, which could require a further procedure to reopen it.

Non-target embolisation: Materials used to block the tumour arteries may be deposited elsewhere in nearby healthy vessels. This is rarely consequential, but it could affect normal kidney tissue or the adrenal gland.

Problems that may happen later

Post-embolisation syndrome is a common side effect and occurs in about 30-80% patients. It causes flu-like symptoms such as fever, tiredness, nausea and pain. It is due to inflammation caused by the AML tissue losing its blood supply. It usually settles within a few days and is managed with rest, fluids, and simple painkillers such as paracetamol.

Other risks

Kidney infections are rare but if they occur, would require antibiotics. We give you a dose of antibiotic before the procedure to reduce risks.

The Interventional Radiology team will be looking after you at UCH. The embolisation is performed by a Consultant Interventional Radiologist who has expertise in image-guided treatments. There are several consultants who deliver this treatment. The team works with other doctors involved in your care.

After you have been seen in the clinic at the Royal Free Hospital, we will ask you to attend a pre-operative assessment appointment at UCH. The purpose of this appointment is to ensure you are well enough to go ahead with the procedure. We will ask about your medical/surgical history and carry out any necessary clinical examinations such as blood tests, a urine test and an electrocardiogram (ECG). It will help us if you could also bring written details of your medicines to the appointment.

What to bring to the preoperative assessment

• Written details of all the medications you are currently taking, including over the counter and herbal remedies.
• Relevant documents such as recent test results or clinic letters from other hospitals.

In this appointment, we will also discuss with you what you need to bring with you for the procedure, when to arrive, when to stop eating and drinking, which medicines to stop, and the need for someone to escort your home. We can also send this information via MyCare (our secure patient app)

Travel and escort arrangements

You should plan how you will travel home after your procedure. Your arrangements may need to be flexible, as you might be ready to go home earlier than expected, or you may need to stay longer if further hospital care is required.

Pain relief at home

Before the procedure, please make sure you have pain relief at home, such as paracetamol and ibuprofen. The hospital does not provide non-prescription medicines when you go home, but you may need them during your recovery.

On the day of the procedure

When you come in for the procedure, please bring all your medications with you.

On arrival, you will be checked into the department by an imaging nurse. The nurse will fill in some paperwork and do some clinical observations-like blood pressure and pulse. You will be asked to put on a hospital gown and will be given some stockings to wear on your legs to reduce the risk of blood clots.

The Radiologist will come and explain the procedure to you and sign off the consent form with you. This is where you have the opportunity to talk to the Radiologist doing your procedure and they will be able to address any concerns you may have.

You will also be seen by the Anaesthetist to talk to you about the anaesthetic that will be given. The procedure is usually performed either under sedation or under a general anaesthetic. If you have any further questions about this, please do not hesitate to ask.

If you have any allergies, you must let your doctor know. If you have previously reacted to intravenous contrast medium (the dye used for CT scans), then you must also tell your doctor about this.

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with procedure, by law we must ask for your consent and will ask you to sign a Consent form. This confirms that you agree to have the procedure and understand what it involves.

The consent form is a form that both you and the operating doctor sign confirming that you have discussed the procedure and been informed of the risks/benefits/alternatives and have agreed to carry on with the interventional procedure. You can have a copy of this form to take with you.

Please feel free to ask any questions that you may have and, remember that even at this stage, you can decide against going ahead with the procedure if you so wish.

You will lie on the X-ray table, generally flat on your back. A needle will be inserted into a vein in your arm, so the anaesthetist can provide you with the anaesthesia medication. You may have monitoring devices attached to your chest and finger and may be given oxygen.

The procedure is performed under sterile conditions and the operating radiologist and scrub nurse will wear sterile gowns and gloves. The skin near the point of insertion, usually the groin, will be swabbed with antiseptic and you will be covered with sterile drapes.

The skin and deeper tissues over the artery will be numbed with local anaesthetic delivered through a small needle. A long fine tube (catheter) is then guided through the network of arteries into the renal artery, and then into the specific arteries that supply the AML. This is performed using X-rays and contrast.

You will be anaesthetised for the procedure and therefore should not feel any significant pain during the case. You might feel some pressure and discomfort.

There should be minimal pain and discomfort post-procedure. Our nurses can give you pain relief if necessary. Any post-procedural pain should reduce significantly by the next day, and if required, paracetamol should be enough to keep you comfortable.

Every patient’s situation is different, and it is not always easy to predict how complex or how straightforward the procedure will be, but it will usually take between 2 and 3 hours.

After the procedure, you will be transported into the recovery area. Our nurses will check your observations regularly.

You will have a small dressing in your groin or wrist where the puncture is made, with no stitches required.

You will have an intravenous drip in your arm throughout your stay so that we can give you fluids or medications if needed.

In recovery, you will slowly be allowed to drink water. If you can tolerate this, then on the ward you will be given something light to eat.

In most cases the procedure can be performed as a day case (home the same day) but sometimes requires an overnight hospital stay. To be able to go home, we will need to ensure you are safe on your feet. When you get out of bed for the first time, you will have a nurse with you in case you feel faint or dizzy.

The Interventional Radiologist will see you prior to being discharged home if you are comfortable to do so. If the procedure is performed as a day case, you must have a friend or family member to accompany you home. You will be given a discharge summary and a supply of pain relief.

When you arrive home

We recommend that you take a week off work after the treatment. It is important to not perform any heavy lifting or strenuous exercise during the first week to avoid damaging the puncture site in the wrist or groin.

Tenderness may last for a week; bruising may go on to two weeks and a small lump may appear which can last up to six weeks. Mild oozing from wound site and bruising is expected but if you notice increasing bruising or swelling at the access site (wrist or groin), you may need an ultrasound scan to check the blood vessel has healed fully.

Wound care

If you have a dressing covering your procedure site, please keep it dry for the first 48 hours. When you take a bath or shower after this time, remove the dressing first. Do not soak the dressing or allow it to stay wet for a long period. Gently pat the area dry with a clean towel.

Managing Discomfort

You may experience some discomfort in your side or back for a few days, and this can be managed as below:

• Take paracetamol 1 gram every six hours. For the first two to three days, it can be helpful to take it regularly even if you do not have pain or temperature, as this may reduce flu-like symptoms.
• If you do not have any issues with your kidney function, you can add ibuprofen 400 mg up to three times a day to help with any pain. You can take it between doses of paracetamol or at the same time, but do not take more than three ibuprofen tablets in 24 hours. However, if you are known to have any impairment in your kidney function, you should speak to the doctors on the day to get further advice about pain relief.

It can be helpful to write down the time you have taken your different medication. This can help you spread your pain killers evenly through the day to give you the best pain relief.

Temperature

It is common to experience a group of symptoms known as post embolization syndrome after this procedure. This happens because the procedure cuts off the blood supply to the AML, causing the treated tissue to breakdown. As your body clears away this tissue, it releases natural chemicals that can cause temporary symptoms such as fever, tiredness, nausea and discomfort in your side or back. These symptoms are a normal part of the healing process and usually improve over a few days.

Follow-up

Six months after embolisation, you will have:

• CT or MRI scan of the kidneys
• Blood tests to check your kidney function.

This duration allows time for the effect of the embolisation to be assessed on imaging. If the procedure has been more complex

or there are specific considerations, then we will organise follow up earlier. Once these tests have been reviewed you will have a telephone outpatient appointment to go over the results and you will be able to ask any further questions you may have.

Advice and support after discharge 

You will receive a call from our clinical nurse specialist a day after you go home, or on a Monday if you are discharged on a Friday.

Consult your GP or 111 if you experience any of the following:

• Signs of urine infection such as pain or burning when passing urine, needing to pass urine more often than usual, cloudy or foul-smelling urine.
• Moderate pain not relieved after following full discharge instructions for pain medication.
• Constipation not relived after taking regular laxatives.

Attend your nearest emergency department (A&E) if you feel unwell or experience any of these issues, taking discharge summary with you:

• Pain when breathing or worsening shortness of breath.
• Severe or increasing pain despite taking your pain medication as instructed.
• Nausea and vomiting that is stopping you eating and drinking more than 24 hours.
• Increasing fever for more than 1 week after the procedure, not relieved by Paracetamol.
• Swelling or bleeding at the needle insertion site.
• Unable to pass urine/ Blood or clots in urine.

We will update your GP after your discharge, but immediately after the procedure they may not be aware of the procedure details. If you see your GP after the treatment, please take your post discharge instructions with you.

Some of your questions should have been answered by this leaflet but remember that this is only a starting point for discussion about your treatment with the doctors looking after you. Make sure you are satisfied that you have received enough information about the procedure.

Interventional Radiology Clinical Nurse Specialist
Telephone: 07974 875 629

UCH Switchboard
Telephone: 020 3456 7890

Address:
Interventional Radiology Imaging Department
University College Hospital
2nd Floor
235 Euston Road
London
NW1 2BU

Radiology Admin enquiries
Telephone: 020 3447 3267

Interventional Radiology
Email: uclh.referrals.interventionalradiology@nhs.net

Hospital Transport Services
Telephone: 020 3456 7010

Procedures

The Imaging Department, Level 2 Podium in the main University College Hospital building with the entrance on Euston Road (see map below).

Travelling to the hospital

No car parking is available at the hospital. Street parking is limited and restricted to a maximum of 2 hours.

Please note the University College Hospital lies outside, but very close to the Central London Congestion Charging Zone.

Tube

The nearest tube stations, which are within 2 minutes’ walk, are:

• Warren Street (Northern and Victoria lines)
• Euston Square (Hammersmith & City, Circle and Metropolitan lines)

Overground trains

Euston, King Cross & St Pancras and Kings Cross Thames link railway stations are within 10-15 minutes’ walk.

Bus

Further travel information can be obtained from the TFL website or by calling 020 3054 4040 14

Hospital transport service

If you need (and are eligible for) transport, please call:

020 3456 7010 (Mon to Fri 8am-8pm) to speak to a member of the Transport Assessment Booking Team.

If you have a clinical condition or mobility problem that is unlikely to improve you will be exempt from the assessment process. However, you will still need to contact the assessment team so that your transport can be booked. If your appointment is cancelled by the hospital or you cannot attend it, please call 020 7380 9757 to cancel your transport.

University College Hospital Area Map