The Embolisation Process

• History of embolisation
• What is embolisation?
• How many embolisation procedures have been performed?
• What does the procedure involve?

History of Embolisation

In the late 1980s a group under the direction of Professor Jacques Ravina, a French gynaecologist, embolised uterine arteries in patients who started bleeding post-operatively. Radiologists started to embolise the uterine arteries pre-operatively to reduce bleeding. Patients started to cancel surgery as their symptoms improved.

What is Embolisation?

Embolisation is the blocking of an artery, the blood vessels supplying an organ, to stop blood flow. As well as uterine fibroids, embolisation can be used to treat:-

• Inoperable cancers
• Before or after invasive surgery, for cancer or gynae procedures to stop heamorrhage [ severe bleeding]
• Aneurysms (dangerous ballooning of a blood vessel) in the brain - avoiding major brain surgery
• Arterio-venous shunts in the lung (blood vessels have direct links between the arterial and venous systems, thus bypassing the heart) - otherwise treated by a heart-lung transplant.
• In accident and emergency departments to stop severe heamorrhage from road traffic accidents etc without the need for invasive surgery.
• Obstetric heamorrhages which can be life threatening such as post partum heamorrhage.

In the case of uterine fibroids small particles are introduced into the arteries supplying the uterus and fibroids and block them. The fibroids, thus starved of blood shrivel and die. There is enough blood supply to the uterus from other arteries (usually the one supplying the ovaries) for the uterus to maintain normal function and fertility.

How many have been performed

There have been at least 100,000 uterine artery embolisation procedures performed around the world to date. FEmISA has recently carried out a survey with the interventional radiologists in the UK and Eire. Over 20,000 have been performed, many routinely and some as part of clinical trials or assessments. UAE/UFE is no longer new.

What does the procedure involve?

An MRI (magnetic resonance imaging) scan is normally performed to determine the number, size and position of the fibroids.

It is important to know if any of the fibroids are pedunculated (on a stalk) and sitting outside the uterus in the abdominal cavity (subserosal). Embolisation used not to be performed on such fibroids, but now can be, by performing embolisation followed immediately by myomectomy to remove that fibroid. Having large fibroids does not stop successful embolisation. If fibroids are very large this will be discussed with you directly by your interventional radiologist. One woman had a fibroid of 21cm, which was successfully treated by embolisation.  Surgery on very large fibroids is associated with heavy heamorrhage.  It is important that the interventional radiologists assesses the MRI scans to decide if a woman is suitable. This cannot be done by gynaecologists alone.

Many centres now give antibiotics to reduce the risk of infection.

The procedure is performed in an angiography suite, not an operating theatre and by an interventional radiologist, not a surgeon. It is carried out under light sedation and local anaesthetic. A catheter is inserted into the bladder before the procedure.

The patient will lie on a table and the radiologist will view what is going on by fluoroscopy, a very low-level x-ray. A small catheter (hollow plastic tube) is inserted into the femoral artery, the blood vessel supplying the leg, in the groin, usually on the right side. The catheter is very small and the incision is only 1-2 mm wide. There is little if any pain. Some radiologists insert catheters in both sides to reduce the radiation dose.

Click the diagram of the embolisation process for a larger image

From time to time he/she will introduce radio-opaque dye (contrast media) down the catheter into the blood vessel to visualise them. A warm sensation may be felt when the contrast media is injected.

The catheter is then advanced into the uterine artery, the blood vessel supplying the womb/uterus. It has two branches. the embolic agent which may be small polyvinyl alcohol (PVA) or gelatin particles or spheres are released which block off the artery supplying the uterus and fibroids. As the blood is arterial, coming directly from the heart, and under pressure, the particles are forced into the smaller vessels supplying the uterus and fibroids where they block them off and form a clot. There is therefore no danger of them moving around the body or being released later.

Click the diagram showing how particles are positioned within blood vessels for a larger image

This procedure is done on both branches of the uterine artery.

Click on the diagram to run an animation showing how the Uterine Embolisation procedure blocks the artery, thus starving fibroids of the blood supply and causing them to shrink over time.

After the second side is embolised - particles are injected, the woman may start to feel cramping pain. Pain varies greatly. Some feel none at all and others need considerable pain relief. Pain is usually controlled with a strong painkiller such as diamorphine and anti-emetic drugs to help to stop sickness.

The pain usually lasts about 12 hours and the next morning the woman can go home with painkillers and anti-inflammatory drugs. Pain usually goes after 24 hours.

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