Teaching Case

A 44-year-old healthy woman with history of uterine leiomyoma presented with a 2-year history of increasing pelvic discomfort. Uterine artery embolisation (UAE) was raised as a possible option which she accepted. Vascular anatomy was unknown, encountering an important variant at the time of the procedure.

Using a unilateral femoral artery approach under fluoroscopic guidance, the right (Fig. 1a) and left internal iliac arteries (Fig. 1b) are accessed with a catheter. Digital substraction angiographic image obtained in the arterial phase failed to reveal normal fibroid vascular supply.

In Fig. 2a catheterisation of the left ovarian artery shows a large fibroid projecting from the uterine fundus (yellow arrow), revealing fibroid arterial supply. Note the characteristic corkscrew appearance of the left ovarian artery (blue arrow).

Angiographic image in Fig. 3a obtained after embolisation reveals successful occlusion of the fibroid vessels (red arrow) while the ovarian artery remains patent.

Pelvic MR images in Fig. 4a-b show the pre-embolisation myoma size (white arrow) which measured 35 x 38 x 33 mm, Vol=22.9 cc, in comparison with the post-embolization size which is 17 x 18 x 15 mm, Vol=2.4 cc, thus demonstrating a >80% decrease in myoma size indicating successful UAE.

Leiomyomas are common benign vascularised tumours of the uterine muscle. [1] They grow during pregnancy and usage of oral contraceptives and disappear after menopause.
Most are asymptomatic, but 20-50% of women present symptoms. [2]

Embolization (UAE) has become the first-line of treatment as an alternative to hysterectomy considering its minimally invasive nature, favourable costs, and associated rapid recovery and return to work. [3, 4, 5] Selective catheterisation and embolisation of both uterine arteries, which are the predominant source of blood flow to fibroid tumours, is the mainstay of treatment. [3]

Indications for UAE include: Heavy/prolonged menstrual bleeding [2], severe menstrual cramping [6], pelvic pressure/discomfort, dyspareunia [7], urinary symptoms [8] and hydronephrosis caused by an enlarged uterus [4].

Contraindications for UAE include: pregnancy, active/untreated infection and suspected uterine, cervical, or adnexal malignancy (unless the procedure is for palliation or adjunct to surgery). Coagulopathy, contrast-medium allergy, and renal impairment are considered relative contraindications. [4]

MR angiography can show the arterial anatomy previous to embolisation. Knowledge of the normal and variant pelvic arterial anatomy is needed to guarantee the safety and success of the procedure. Uterine arteries usually supply uterine leiomyomas and the uterus, they arise as the first or second branch of the anterior division of the internal iliac artery. [3] Among variants of fibroids arterial supply include: termination of the iliac artery in trifurcation, common trunk between the uterine arteries and vesical or vaginal artery, congenital absence of uterine arteries and aberrant uterine vessels.
Ovarian arteries can also supply fibroids and may be a cause for failure in the procedure, this occurs in 5-10%, usually found in women who have undertaken pelvic surgery, with previously diagnosed tubal/ovarian disease and/or large fundal fibroids. [4]

Treatment efficacy is similar between the embolic materials. [9] As the target of embolisation is the perifibroid arterial plexus, the main uterine artery should be spared. [3] UAE is stopped when left-to-right anastomoses are seen, when a column of contrast material is detected in the uterine artery or when reflux of contrast toward the uterine artery origin or into the hypogastric artery is found. [10]

Follow-up after treatment usually show changes consistent with haemorrhagic infarction, 35-60% reduction in uterine volume and approximately 40-80% reduction in fibroid volume after 3-6 post-UAE. [3]
Treatment failure and recurrence occurs in 10% of patients, common causes include: Unilateral UAE due to difficulty in catheterisation and uterine arterial supply in the presence of ovarian arterial supply. [3]