Vascular Anomalies (AVM)

"Vascular anomalies" refers to a broad and complex spectrum of conditions including vascular tumours (e.g., haemangioma) and abnormally formed or connected vessels. Such lesions can occur in isolation (sporadically) or as part of a syndrome.

"Vascular malformations" refers to the subset of vascular anomalies where there are abnormally formed or connected vessels, including arteries, veins, or lymphatic vessels. 

In brief, vascular malformations can be divided into:

• Arteriovenous malformation (AVM; high-flow)
• Arteriovenous fistula (AVF; high-flow)
• Venous malformation (low-flow)
• Lymphatic malformation (low-flow)

Many vascular malformations are asymptomatic and do not require treatment, however depending on size and location, symptoms may include:

• Pain
• Swelling
• Thrombosis
• Functional impairment
• Cosmetic concern
• Cardiac (heart) impairment
• Recurrent infection

As vascular malformations are very variable and complex, individualised treatment will depend on the particular type of lesion, location, and symptoms. Treatment may be with medications, sclerotherapy, embolisation and/or surgery, and occasionally more than one type of treatment and more than one treatment session is required to achieve a good outcome.

Sclerotherapy refers to injection of a liquid medication into the abnormal vessels of a vascular malformation under imaging guidance, commonly ultrasound (US) or angiography (x-ray). It is most commonly used in lymphatic or venous malformations. The liquid medication injected in sclerotherapy works by causing irritation to the inside of the abnormal vessels, which then swell temporarily, before shrinking down over time and scarring. There are numerous different liquid medication agents that may be used in sclerotherapy, and the most appropriate will be selected based on the type of lesion and individual factors:

• Alcohol (ethanol)
• Lauromacrogol (Aethoxysklerol)
• Sodium tetradecyl sulfate (STS)
• Polidocanol
• Doxycycline
• Bleomycin

Effectiveness

• Outcomes are highly variable depending on the characteristics of the malformation, however in general, approximately 80% of patients will have improvement in symptoms after sclerotherapy for a venous or lympatic malformation
• Most people will require more than one treatment to achieve a good result

Complications

• Skin breakdown or ulceration (<5%)
• Regrowth and recurrence of the malformation (up to 30%)

Embolisation refers to a procedure performed via a catheter inside the feeding artery and/or outflow vein channels of an arteriovenous malformation (AVM) or fistula (AVF) to block (occlude) the vessels. Once the high-flow vessels are occluded, the AVM or AVF typically shrinks down and becomes less symptomatic. There are numerous difference embolic agents that may be used in an AVM or AVF embolisation procedure, and the most appropriate will be selected based on the type of lesion and individual factors:

• Alcohol (ethanol)
• Histoacryl (glue)
• Glubran
• Coils
• Plugs
• Stents

Effectiveness

• Outcomes are highly variable depending on the characteristics of the malformation, however in general, more than 70% of lesions can be completely treated with embolisation
• Some people will require more than one treatment to achieve a good result

Complications

• Skin breakdown or ulceration (<5%)
• Non-target embolisation
• Residual or recurrent malformation

1. A specialist interventional radiologist (IR) will first consult and examine you to determine your suitability for sclerotherapy or embolisation treatments. If your vascular malformation does not require treatment or is better treated by another specialist, e.g., with medication or surgery, the interventional radiologist (IR) will discuss this with you and arrange referral to another specialist as appropriate
2. Most sclerotherapy and embolisation procedures are performed under general anaesthetic or deep sedation with a specialist anaesthetist. Local anaesthetic may also be used.
3. Depending on the individual characteristics of the vascular malformation, there may be needles inserted directly into the lesion through the skin, or a catheter tube inserted via the artery or vein, typically in the groin. 
4. The procedure typically takes between 1 and 2 hours
5. There may be a closure device or "stitch" used to seal the site where the catheter was inserted into the artery
6. You will be required to rest and recover in bed for up to 4 hours post-operatively, which is to minimise bruising in the groin.
7. It is common for the vascular malformation lesion to swell and become more painful temporarily after sclerotherapy or embolisation. This is expected and is a direct effect of the treatment. The swelling typically resolves within 2-3 weeks after the procedure.
8. Many vascular malformations require multiple treatment sessions, and these will be arranged at suitable time intervals, as well as ongoing follow up in the outpatient clinic

Interventional Radiologists (IRs) are specialty trained in the treatment of vascular malformations, including the pre-procedural assessment, operation and post-procedural care. Interventional Radiologists (IRs) are extensively experienced in sclerotherapy and embolisation procedures, and regularly perform similar procedures all throughout the body, including the chest, abdomen, pelvis, upper limbs, and lower limbs.

The assessment and management of vascular anomalies is best done as part of a multidisciplinary team of doctors from different specialties with an interest and experience in vascular anomalies. As such, your case will generally be discussed with colleagues from other specialties including dermatology, surgery, and paediatrics, as appropriate. There may be treatments other than sclerotherapy or embolisation that are more appropriate for an individual case, and you may be referred to consult with another specialist if this is the case.

If you would like to consult with an Interventional Radiologist about a vascular malformation (AVM), please send a referral for consultation, including the following

• Imaging results including ultrasound, CT, and other imaging
• Records of consultations with other doctors and specialists

Public eligible patients can undergo the treatment with no out-of-pocket expense in the public system.