Arteriovenous Malformation (AVM)

Introduction

Arteriovenous Malformation or AVM is a medical disorder of blood vessels that can happen anywhere in the body, including the brain. An AVM can lead to bleeding and damage to the surrounding tissues. There may not be any symptoms at all until there is bleeding in the area where the abnormal connection between arteries and veins has formed. Treatments for AVM involve removing an abnormal connection, shrinking it, or stopping blood from flowing through it. Let’s understand this condition in detail.

What is Arteriovenous Malformations (AVM)?

An arteriovenous malformation is a rare condition in which blood vessels (arteries and veins) get tangled. This may usually occur during development before birth or shortly after birth. The arteries supply blood from the heart to the rest of the body’s organs and tissues, while the veins return blood devoid of oxygen to the heart and lungs. In normal situations, the exchange occurs through capillaries, which connect the arteries and veins.

When an AVM forms, the capillaries aren’t there to connect the two blood vessels. This results in high pressure blood flow from the arteries to the veins. Such abnormal connection and high pressure blood flow from an artery to a vein can cause vessel rupture and bleeding in the area where the AVM has formed.

Types of AVMs

There are two main types of AVMs, depending on where they form the connection.

• Brain Arteriovenous Malformations

Such AVMs form within the brain tissues or on the surface of the brain. They can mostly occur in the brain, brainstem, and spinal cord.

• Peripheral Arteriovenous Malformations

AVMs forming anywhere in the body other than the brain are known as peripheral arteriovenous malformations. They can develop anywhere in the body, including the face, arms, or legs, and even in tissues and organs like the lungs and heart.

How do AVMs Form?

In the majority of cases, AVMs form during the developmental phase of a foetus (congenital) or shortly after birth, but the exact cause of AVM formation is not known. In rare cases, having a family history of AVMs can increase the risk of developing them.

What are the Symptoms of AVM?

AVMs are quite rare and may not exhibit any symptoms at all. Sometimes, it goes undiagnosed until it starts bleeding. If AVM symptoms have not appeared by the age of 50, they may not appear at all. Only about 12% of those with AVMs actually ever show symptoms.

AVM symptoms are various, may include:

• Seizures with or without loss of consciousness
• Headache
• Dizziness
• Nausea and vomiting
• Muscle weakness or complete paralysis
• Numbness or tingling sensation
• Back pain, which can be sudden and severe, or weakness in the lower body (hips) and legs to your toes
• Problems with movement, thinking, speech, memory, thinking, balance or vision
• Mental confusion, hallucinations or dementia
• Shortness of breath during exertion
• Coughing up blood (if AVM is in the lungs)
• Abdominal pain
• Lumps on the arms or legs or the trunk
• Swelling with pain

Are there any Complications of AVM?

AVMs can cause complications, especially if they form in the brain.

• Brain bleed: Often, the first sign of AVM in the brain is brain bleed (haemorrhage), which can lead to brain damage and stroke.
• Seizures: AVMs can also lead to a rush of electrical signals in the brain that lead to passing out and having trouble controlling movements.
• Aneurysm: This is a balloon-like bulge feeding into or around the AVM. It can increase the risk of rupture and bleeding-related symptoms in the brain.
• Brain damage: AVMs can lead to difficulties in thinking, mental processing, memory, or understanding speech.
• Coma and/or Death: In rare cases, if an AVM rupture causes a large bleed in the brain, it can lead to coma and potentially even death.

How are AVMs Diagnosed?

AVM diagnosis by a doctor involves asking about the details of AVM symptoms and a physical examination of the symptoms, if any. They may also listen for a bruit, which is a rapid blood flow sound that can be heard in the blood vessels when an AVM has formed. To detect the presence and extent of AVMs, they may also recommend a number of imaging tests, such as:

• Magnetic Resonance Imaging (MRI) scan
• Computed Tomography (CT) scan
• Catheter Angiography, which involves using a catheter to investigate a blood vessel supported by X-ray images made visible by special dyes

In case of brain arteriovenous malformations, doctors may recommend different brain imaging tests, like:

• Cerebral Magnetic Resonance Angiography (MRA), which involves using a magnetic field and radio waves to produce detailed images of the blood vessels in and around the brain
• Computed Tomography Angiography (CTA), which provides detailed X-ray images of the blood vessels
• Transcranial Doppler ultrasound, which helps determine the speed of blood flow through the brain

It often occurs that AVMs are diagnosed with imaging tests when looking for possible causes of another condition, such as injuries, vision problems, or severe headaches. In other cases, they may be diagnosed only after bleeding symptoms appear. So, it can delay the diagnosis, and the treatment

for AVMs thereafter. Therefore, any suspicious symptoms of AVMs shouldn’t be ignored, and prompt medical attention should be sought.

What is the Treatment for AVM?

Treatment for arteriovenous malformation can depend on a number of factors, including:

• the type, size, and location of the AVM
• anatomy of the arteries and veins
• the risk of AVM rupture
• specific AVM symptoms
• patient’s age
• the overall health of the patient

Ideally, the goal of AVM treatment is to reduce the chances of bleeding or remove it permanently. Sometimes, an AVM may be monitored closely to look for changes or problems. There are many ways to manage AVM treatment.

1. Medications

Medications may be prescribed by a doctor to manage the physical symptoms of AVMs. These medications may include:

• Anti-seizure medicines
• Blood pressure medication
• Pain relievers

2. Surgery

The best way to go about AVM treatment is surgical intervention. It may be recommended when there is a high risk of bleeding from an AVM. The goal of surgery for AVM might be to remove it completely. Surgery may be recommended to a patient when surgeons may be able to remove the AVM with minimal risk of damaging the surrounding tissues.

In a surgical procedure to remove an AVM, a surgeon makes a cut near the AVM and seals the surrounding blood vessels so that they don’t bleed. Then, they redirect the blood flow to normal blood vessels. After surgical treatment for AVM, the patient is likely to be kept in the hospital for observation and recovery and may need short-term rehabilitation as well.

3. Embolisation

This is another surgical technique that involves using a catheter to slow down or stop the flow of blood through an AVM. In this technique, the concerned surgeon inserts a catheter in the groyne or wrist and takes it to the location of the AVM. Once the area of entanglement has been reached, they release a glue-like substance, coil, or another substance into the AVM that helps to stop or slow down the blood flow. This approach is employed in case AVMs are large and have a lot of blood flowing through them so that the risk of rupture can be reduced.

4. Gamma Knife Radiosurgery

This is another surgical approach that employs highly focused radiation beams to slowly shrink, scar, and dissolve an AVM over the course of a few years, or to make the AVM easier to be removed through surgery.

AVM Treatment at Apollo Hospitals, Karnataka

At Apollo Hospitals, Karnataka, we recognise that each case of AVM can be unique, which is why we ensure the provision of individualised care for AVM treatment in Bangalore. AVMs can be a complex network of blood vessels forming in delicate areas. Our surgical team is equipped with cutting-edge technology-enabled state-of-the-art equipment and facilities to achieve optimal results for even the most complicated cases of AVM. With advanced AVM treatments and focused, personalised care, we ensure our patients get world-class healthcare at the best hospital for AVM treatment in Bangalore – Apollo Hospitals, Karnataka.

Book an appointment with our top neurovascular doctors to address your health concerns at Apollo Hospitals, Karnataka.