Vascular malformations, or vascular anomalies, are abnormal growths of arteries, veins, and/or lymphatic vessels that can occur anywhere in the body. These malformations lack a normal ordered pattern and can invade surrounding tissues. While typically non-cancerous, they can grow and cause complications.
Arteriovenous Malformations (AVM)
AVMs are tangled blood vessel abnormalities affecting the connection between arteries and veins which may develop shortly before or after birth, disrupting normal blood flow. They can be most commonly found in the head and neck, and have the potential to cause severe complications such as seizures, strokes, and breathing problems. While often asymptomatic, they can lead to bleeding and exhibit symptoms such as skin discoloration, swelling, and discomfort.
- Skin discolouration
- Swelling
- Skin over AVM being more delicate/susceptible to ulcers
- Discomfort – Pain and aching
For brain AVMs:
- Headaches, pain in one area of the head
- Muscle weakness or numbness
- Seizures
- Speaking difficulty
- Confusion
The exact causes of AVMs are unknown, but they are believed to be congenital. A family history of AVMs or other conditions can increase the risk of developing an AVM. Symptoms can manifest at any age, with pregnant women potentially experiencing worsened symptoms due to increased blood pressure.
Venous Malformations (VM)
VMs are abnormal enlargements of veins, appearing as bluish or skin-coloured lumps under the skin. They can lead to reduced blood flow and blood clot formation.
- Cosmetically unpleasant growths/soft lumps evident to the naked eye
- Pain and discolouration of the skin around the growth
- Loss of limb function. Including muscle weakness, numbness, and in severe cases, paralysis of a limb.
- A vascular malformation inside the brain can bleed, causing a stroke or seizures (fits) due to pressure on the brain if not treated early on.
VMs are predominantly congenital, but not necessarily hereditary. In some rare cases, trauma can also contribute to their development.
Case Study 1
Patient presented with right mid-thigh vascular anomaly, with patent arterial and venous branches. MRI scans showed arterial feeders from branches of the profunda femoris artery, with large venous channels seen. The size of the lesion was approximately 5.5 x 4.5cm. The decision was made to treat the vascular malformation with embolisation and cryotherapy.
A right leg angiogram was performed to determine the extent of the vascular malformation and to identify the target vessels. The feeder branches of the VM were identified and embolised using Onyx embolic agent, and the vessels were observed to have sealed after a following angiogram was performed. Residual channels were treated using cryoablation under ultrasound guidance.
Fig 1: Cryoablation (Deep Freezing) procedure to treat venous channels
Patient reported lessening pain in thigh 1 month post-op, and an ultrasound performed 6 months revealed well closed vascular channels, with no recurrent vein channels.
Case Study 2
Patient presented with a history of a venous malformation in the left gluteal region, resulting in increasing pain. MRI scans revealed that a lesion was present, and surgery and cryotherapy were decided against due to the involvement of the sciatic nerve. Hence, the decision was made to proceed with sclerotherapy.
A pelvic angiogram was first performed to determine the affected vessels. Sclerosing agent was then injected into the vessels under fluoroscopic guidance, and multiple venous channels were embolised, reducing abnormal blood flow.
Ultrasound scanning showed occlusion of the injected channels, and the patient experienced a significant reduction in tenderness. Ultrasound showed reduction for size of the lesion.
Lymphovenous Malformations (LVM)
LVMs are rare, non-malignant masses consisting of fluid-filled spaces caused by abnormal lymphatic system development. Superficial lymphatic malfunctions may look like small and soft bumps under the skin, whereas some LVMs may not be visible on the surface of the body. Regardless of the LVM size, they can appear anywhere in the body and may result in functional impairment and disfigurement.
Symptoms vary depending on the location and size of the malformation. Complications can occur with LVMs, including recurrent inflammation, or bleeding into the malformation. When the LVM becomes inflamed, it can cause swelling and redness of the skin (cellulilitis), and recurrent cellulilitis can result in pain and disfigurement of the affected area. Bleeding into the LVM can also cause severe pain, swelling and enlargement of the malformation in the affected area.
LVMs occur when the lymph veins fail to form and develop correctly during pregnancy.
Dural Arteriovenous Fistula (DAVF)
DAVF is a rare vascular condition characterized by abnormal connections between arteries and veins in the brain covering (dura mater). Blood flows at high pressure from arteries into veins, congesting the brain’s venous system and potentially causing brain dysfunction. DAVFs are found in the brain and spine, and tend to occur later in life.
An individual with DAVF may not experience any symptoms at all. Symptoms that do appear can range from mild to more aggressive. An additional, prominent sign of DAVFs is pulsatile tinnitus. Pulsatile tinnitus occurs when a patient begins to hear the sound of blood rushing from the arteries through the fistula into the veins, characterised by a persistent whooshing to-and-fro sound near the ear. However, it is essential to note that patients suffering from pulsatile tinnitus do not always have a DAVF but may have some other condition.
Mild:
- Problems seeing
- Bulging of the eye (proptosis)
- Swelling in the eye lining
Aggressive: can often result from haemorrhages of the affected area
- Seizures
- Sudden onset of headaches
- Difficulties speaking
- Dementia
- Coordination issues
- Burning or prickling sensations around the affected area
- Nausea or vomiting
There is no clear reason as to why DAVFs form.
However, some patterns that have been identified include:
- Previous thrombosis vein
- Areas of the body with a history of trauma/past surgery where a fistula may develop.
- Family history of thrombosis can make a patient more susceptible to DAVFs.
- Affected age group is predominantly 50-60 years of age but may even affect children.
Case Study 1
Patient presented with a large, extremely high flow cerebro arteriovenous fistula supplied by multiple scalp and meningeal arteries through trans-osseous feeders.
An angiogram was performed through the right and left internal and external carotid arteries, as well as the vertebral arteries. Massive venous congestion and drainage was observed. The fistula was occluded using a double microcatheter technique through the trans-arterial route using onyx embolising agent.
Complete occlusion of the fistula was achieved.
Hemangioma
A hemangioma is a non-cancerous growth of blood vessels often observed as red birthmarks on infants which can be present anywhere on the body. While most hemangiomas resolve without treatment by the time a child turns six years old, some may persist.
Symptoms are usually limited to the appearance of red birthmarks which are smooth and raised in appearance. However, in some cases, hemangiomas may bleed and develop into a sore, resulting in pain and the potential for infection. Hemangiomas on the organs can also cause some complications, including pain where it is located, although this is very rare.
The exact cause of hemangiomas is unclear. However, it has been noted that they are more common in infants with low birth weight, premature infants, and multiple births.
Medications such as propranolol and beta-blockers can be used.
Interventional therapies are an alternative method to address persistent hemangiomas and minimize associated abnormalities for patients who do not respond to medication or would prefer a non-pharmacological route.
Sclerotherapy: It is a minimally invasive procedure that involves the injection of a chemical solution into a blood vessel, which causes inflammation in the blood vessel walls, eventually resulting in the blood vessel occlusion.
Laser Therapy: Lasers may be used to remove blood vessels that remain on the surface and minimise any abnormalities left by the hemangioma, such as unevenness of the skin.
