Embolisation: When, Where And How?

Introduction

 


There have been major advances in the development of the field of interventional radiology (IR). These have been coupled by improvements in technology, particularly the embolic agents.

The wide array of end organs which can be embolised for various emergency and elective conditions is ever increasing. This has been partly facilitated by better team working and multi-disciplinary approach to disease management. We perform a wide range of embolisation procedures, based on the organ systems:

1. Uterine Artery Embolisation (UAE)
UAE is an IR technique that offers a safe alternative to hormonal therapy and open surgical procedures for symptomatic fibroids. The commonest symptoms are heavy and /or prolonged menstrual bleeding, pain, fibroid bulk symptoms, GI or genitor-urinary symptoms.

There is growing evidence on the efficacy of UAE which has led to its acknowledgment as a treatment for symptomatic uterine fibroids and has been incorporated into the NICE guidelines published in Jan 2007.

Tris-acryl porcine gelatin microspheres (Embospheres: Biosphere Medical, Rockland, MA) are a very commonly used embolic agent. The spheres are compressible, which allows easy passage through a microcatheter with a luminal diameter smaller than that of the spheres. The size of the Embospheres used is 700-900 microns.

In recent years, UAE has been increasingly accepted as safe and effective and a number of studies have confirmed the effectiveness of uterine embolisation at one year follow up.

2. Liver Embolisation
Hepatocellular carcinoma HCC is the most common primary malignant tumour of the liver (90%) with an increasing incidence in the West.

Normal liver is supplied predominantly by the portal venous flow while HCCs are supplied by abnormal tumoural arteries. This is due to increased oxygen requirement locally coupled by angiogenesis and portal occlusion by tumour progression.

Transarterial chemeombolisation (TACE) can prolong survival in patients with unresectable HCC. However, variations in patient selection, technique, chemotherapeutic and embolisation agent selection can all influence outcomes.

Most HCCs arise in cirrhotic livers. If the liver disease is well compensated, superselective TACE or Transarterial embolisation (TAE) needs to be considered, to try and preserve normal function to avoid decompensation. A wide range of embolic agents can be used from 300 – 500 microns Embospheres up to 700 – 900 microns including the newer agents like Hepaspheres.

There is no clear data to show that one embolic / chemotherapy combination is clearly superior to others but there is evidence to show improved survival benefits for TACE/TAE.

The principles of treatment remain constant and are to induce ischaemia within the tumour leading for focal necrosis and volume reduction, whilst sparing normal hepatic tissue.

Prior to the procedure the liver arterial anatomy needs to be evaluated using arterial phase CT. When technically possible, TACE treatment should always be superselective. This minimises iatrogenic liver damage and reduces the need for repeated treatments.

Repeat procedure requirement is based on tumour response, and the ability to tolerate further procedures. Incomplete or partial responders should receive a repeat treatment if the patients’ condition permits, within eight weeks of the previous treatment.

Other hypervascular liver lesions like Carcinoids can also be embolised with good symptom control using the same embolisation principles as with Embospheres of varying sizes. However, hormonal blockade needs to be evaluated prior to the procedure to avoid Carcinoid crises.

3. Skeletal Metastasis Embolisation
Renal cell carcinoma metastases have been successfully embolised using small Embospheres (usually 300 – 500). They have been treated in a wide array of long bones as well as vertebral bodies with no significant adverse effects.

As well as providing information on the range of Embospheres, Hepaspheres and their accessories, BVM also provides product demonstrations and helps with the establishment of UFE clinics.

For further details of these, or for literature, please call BVM on 01455 614555.

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