By Dr SEE Teik Choon, FRCS, FRCR, Consultant Interventional Radiologist, Cambridge, UK

Discuss this topic at the Radiology Malaysia Forum

Uterine fibroids are common in women of reproductive age and the main issues are fertility potential and the management of the symptoms. Uterine fibroids cause a variety of symptoms with different levels of severity. The guidelines issued by the American College of  Obstetricians and Gynaecologists (ACOG) suggest that asymptomatic women should be managed expectantly, while for those with mild symptoms it would be desirable for intervention to be as close to the desired pregnancy as practical given the inherent risk of recurrence (1). 

Treatment for fibroids that cause severe bulk related symptoms or/and menorrhagia are usually indicated. Optimal treatment modality should be based on symptoms, size and site of fibroids, fertility needs and the overall risks and benefits of the treatment. Traditionally this would usually involve hysteroscopic resection or a hysterectomy. 

The first report of uterine artery embolisation (UAE) for fibroids was published in 1995 (2). Subsequently there has been an enormous interest in this treatment modality worldwide. In the UK, UAE can now be routinely offered as a primary treatment for uterine fibroids outside of clinical trials, although it is recommended that all procedures are registered. The main objective of UAE is elimination of the symptoms with fibroid shrinkage an additional advantage. The results of UAE are encouraging with 58% reduction of fibroid volume after 6 months and improved symptoms in 91% of women (3). The majority of shrinkage occurs within a 6 month period but some further reduction in size occurs between 6 and 12 months (4). In a review of the published data involving 60-305 patients (5), symptomatic improvement rate was between 80-92% and hysterectomy rate of 0% and 2%. This is a good outcome compared to the satisfaction rates from hysterectomy which was reported in excess of 90% (6). Interestingly, improvement in menorrhagia was unrelated to initial fibroid size or amount of fibroid shrinkage (7).
 

Most centres would admit the patient for overnight stay mainly for pain control but UAE can be performed on an outpatient basis, provided that patients are appropriately advised and medical attention is available when required. Imaging assessment of the fibroids can be performed with ultrasound or MRI. Volume measurements are obtained pre and post UAE. Patients are counselled prior to the procedure. Prophylactic antibiotics are indicated.
 

UAE is mainly performed by interventional radiologists who are familiar with the techniques of vascular access, catheter manipulation as well as embolisation. The procedure is performed under local anaesthesia, intravenous analgesia, and sedation if required. The right common femoral artery is punctured and access is maintained by a 5 Fr sheath. A cobra catheter is used to crossover the aortic bifurcation and cannulate the contralateral internal iliac artery. A limited arteriogram is then performed to localise the left uterine artery. A coaxial system may be required to selectively cannulate the uterine artery. Spasm may occur and this may result in inadequate embolisation. This may be relieved with glyceryl trinitrate or the procedure may be stopped for a few minutes. Once the uterine artery has been catheterised, embolisation can then be performed. The procedure is repeated for the ipsilateral uterine artery. Cannulation of the ipsilateral internal iliac artery may be difficult and a different shape catheter such as an Omni SOS catheter may be required. If it is not possible to perform ipsilateral cannulation then a new access can be obtained from the opposite groin puncture and a crossover embolisation can be performed as described.
 

It is important to avoid excessive screening and image acquisition in order to avoid extensive ovarian radiation exposure. Radiation can be reduced by using low frequency pulsed fluoroscopy, appropriate collimation, roadmap-guided manipulation, and avoid unnecessary image magnification as well as reducing the distance between the image intensifier and the patient. Crossover catheterization of the internal iliac and/or uterine arteries may be easier to perform and hence reduces the screening time, compared to ipsilateral cannulation.
 

The embolic materials commonly used for UAE are non-spherical polyvinyl alcohol (PVA) particles, trisacryl gelatine microspheres (eg. embospheres), and gelatine sponge. The embolisation material should be injected under free flow condition although some embolic materials may cause proximal vascular aggregation or occlude the microcatheters. Currently there is very little evidence concerning the choice of the most effective and safest embolic agent.
 

Complications of the procedure include groin haematoma and contrast medium reaction which are intrinsic to all vascular interventional procedures. Non-target-organ embolisation is uncommon and this is can be minimised by injecting the embolic agent carefully according to flow.

Post-embolisation syndrome is common and all patients should be warned regarding nausea, vomiting, low grade fever, malaise, and pain. Symptoms can vary in intensity and may last 2 to 7 days. Pain should be adequately controlled with intravenous analgesia during the procedure and possibly for a further 24 hours before switching to oral analgesia. Post embolisation syndrome can be difficult to differentiate from infection which is serious and should be considered if there is persistent high temperature and raised white cell count.

An infection rate of 1-2% has been reported (5) and this may occur even months after the procedure. It is more common with larger fibroids and may necessitate a hysterectomy. Fibroids extrusion occurs in about 10% of cases with small fibroids being expelled spontaneously while larger ones may necessitate a minor surgical procedure for removal, especially if impacted at the cervix (5).  Benign chronic discharge is not uncommon affecting up to 7% of patients (8). It is more likely to occur when the fibroids are large.

Amenorrhea is highly age-dependent. The incidence of ovarian failure is lower than 5% in women under the age of 45 (9) but it has been estimated at 43% in women older than 45 years (10). As yet there is no established data on the effect of UAE on pregnancy and fertility.

The location of the fibroids may also have an impact on the success or the risk of the procedure. There is a general consensus that pedunculated and mainly subserosal fibroids do not respond well to fibroid embolization and that the procedure is more effective for interstitial and submucosal fibroids. There is also the concern of totally necrosing the pedunculated fibroid with consequent infection. In a patient with multiple fibroids in different locations, resection of the pedunculated subserosal fibroid combined with UAE of other fibroids should be considered. Infective complications are potentially more likely with submucosal fibroids where exposure to intracavitary pathogens may occur (11).

There is no doubt that UAE is increasingly performed worldwide. It is minimally invasive compared to myomectomy, hysterectomy or laparoscopic myolysis. The evidence so far suggests that it is effective to control bulk-related symptoms and menorrhagia with acceptable risk but longer term data is required to evaluate its effect on fertility.
 

1. ACOG practice bulletin: surgical alternatives to hysterectomy in the management of leiomyomas. Int J Gynaecol Obstet 2001; 73: 285-294.

2. Ravina JH, Herbreteau D, Ciraru-Vigneron N et al. Arterial embolisation to treat uterine myomata. Lancet 1995; 346: 671-672.

3. Watson GM, Walker WJ. Uterine artery embolisation for the treatment of symptomatic fibroids in 114 women: reduction in size of the fibroids and women’s view of the success of the treatment. Br J Obstet Gynaecol 2002; 109: 129-135.

4. Walker W, Green A, Sutton C. Bilateral uterine artery embolization for myomata: results, complications and failures. Min Invas Ther & Allied Technol 1999; 8:449-454.

5. Belli AM. Uterine artery embolization for the treatment of fibroids. CME Radiol 2002; 3 (1): 20-25.

6. Dwyer N, Hutton J, Stirrat GM. Randomised control trial comparing endometrial resection with abdominal hysterectomy for the surgical treatment of menorrhagia. Br J Obstet Gynaecol 1993; 100: 237-243.

7. Pron G, Bennett J, Common A, et al. The Ontario Uterine Fibroid Embolization Trial. Part 2. Uterine fibroid reduction and symptom relief after uterine artery embolization for fibroids. Fertil Steril 2003; 79: 120-7

8. Reidy JF, Bradley EA, Forman RG et al. Uterine artery embolization. Results in 234 patients [abstract]. Minim Invasive Ther Allied Technol 1999; 8 (Suppl): 26.

9. Walker WJ, Pelage JP, Sutton C. Fibroid embolization. Clin Radiol. 2002 May;57(5):325-31. Review.

10. Chrisman HB, Saker MB, Ryu RK et al. The impact of uterine fibroid embolization on resumption of menses and ovarian function. J Vasc Interv Radiol. 2000 Jun;11(6):699-703

11. Pelage JP, Le Dref O, Soyer P et al. Fibroid-related menorrhagia: treatment with superselective embolization of the uterine arteries and mid-term follow-up. Radiology 2000; 215:428-431.