A geometric graphic for the article about congenital vascular malformations (CVM)

The vascular system, also called the circulatory system, is a network of vessels that carries blood throughout the body- delivering essential nutrients and oxygen, and taking away waste material. When one of these vessels is not formed normally (malformed), connected abnormally, or not formed at all, this can affect the body in many different ways. This condition is generally called a congenital vascular malformation (CVM).

Article Reviewed by Dr. Alan Matsumoto and Dr. Auh Whan Park

Congenital vascular malformations (CVM) is an umbrella term for abnormal clusters of blood vessels formed during fetal development- whether made up of arteries, veins, capillaries, lymph vessels, or a combination of these vessels. CVM is rare, present in about 1% of all births, and varies from harmless birthmarks to painful growths that can cause pain, swelling, and bleeding.

While many of these malformations are apparent at birth and grow as the child grows, some do not become detectable until later. The abnormal blood vessel connections may be more apparent during developmental changes (such as puberty or pregnancy) when blood flow increases.

Types of Vascular Malformations & Symptoms

As mentioned above, vascular malformations can form from abnormalities in a variety of blood vessels. They vary greatly in appearance, and each come with their own set of symptoms. The types of vascular malformations include:

  • Venous malformations (VM)- This is the most common type of CVM and appears as unsightly dilated veins or clusters of dilated veins on the surface of the skin. While VMs do not generally cause circulation problems or serious health issues, they can sometimes become swollen or painful and possibly cause blood clots. If a VM is near a sensitive area of the body such as an eye or a joint, they can also cause functional problems with sight or movement.
  • Lymphatic malformations- This is a fairly common type of CVM that affects the lymphatic system, a network of lymph nodes and channels that works to rid the body of waste and toxins. The malformation of lymphatic channels can slow or stop the flow of lymphatic fluid, a fluid containing white blood cells that fight infection. This can cause swollen or enlarged lymph vessels that can appear like very small water balloons underneath the skin. Lymphatic malformations may be at a higher risk of developing an infection if the lymphatic system is unable to properly rid the body of toxins.
  • Capillary vascular malformations- This uncommon type of CVM affects very small blood vessels underneath the surface of the skin.  Because they appear as patches of pink or purple skin, capillary malformations are nicked-named port wine stains. If capillary malformations form on the head, patients may be at risk for glaucoma or seizures.  
  • Arteriovenous malformations (AVMs)- This type of CVM occurs when there are abnormal and direct connections between the arteries and veins. AVMs result in high blood flow from the artery, causing swollen arteries and/or veins to be visible underneath the skin. While AVMs are the rarest forms of a CVM, it poses the most serious health threat as it can cause significant pain, bleeding, and strain on the heart.

Diagnosing Vascular Malformations

While some CVMs may be apparent at birth, many may go unnoticed until later in life or become apparent due to some localized trauma. Since CVM’s are distinguishable by their visual appearance, your doctor will first perform a physical exam. This is usually followed by more detailed imaging tests to diagnose and better define the type and extent of the CVM. These imaging tests may include:

  • MRI– a magnetic resonance imaging (MRI) scanner uses magnetic waves to create detailed images of the CVM and the tissues and organs it involves without the use of X-rays. These pictures give the doctors a better understanding of the type and extent of the CVM.  
  • CT– a computed tomography (CT) scanner uses X-rays to create detailed images of the CVM. This also shows the extent of the CVM and the tissues involved.  
  • Ultrasound– uses sound waves and no X-rays to take pictures of the body. This test is useful for vascular malformations near the surface of the skin and is often used for guidance during the treatment of VMs as well.
  • Angiogram– This is a special type of X-ray used to look at blood vessels that have been injected with contrast dye using a small catheter that is placed into the blood vessels of interest. These pictures give the doctor a clearer understanding of how the blood vessels are flowing and help to define the type of CVM.


Because CVMs are complex and vary widely–not only in the types of blood vessels they involve but also in the location and severity of symptoms–treatment options vary greatly as well. Symptoms of CVMs may range from cosmetic concerns to daily pain, formation of blood clots, bleeding, skin breakdown or ulcers, strain on the heart, nerve injury, or loss of functionality in the areas of the body they affect.

After your doctor diagnoses a CVM , they will work to understand the type, extent, and significance of the CVM to your overall health. Once your doctor has a thorough understanding of the CVM, they will work with you to find the best treatment option specific to your body.  

The interventional radiologists at UVA offer minimally invasive treatment options tailored to the specific type of CVM and symptoms associated with the CVM. Embolization is a technique used to slow or permanently cut-off blood supply to and from a CVM. Interventional radiologists use fluoroscopy, a type of x-ray picture, to see inside a patient and guide the treatment of the abnormal blood vessels. A small catheter or needle is used to administer the blocking agents, such as medical grade glue, small beads, liquid agents that cause the abnormal vessels to clot off, or metal coils or plugs that block the flow of blood. The embolization procedure is done to eliminate or reduce the size and symptoms related to CVM, as well as the risks of bleeding, skin ulceration, or heart strain.

Depending on the size and location of the malformation, it is typically necessary to perform more than one procedure in order to reduce the symptoms and size of the CVM. On occasion, a combination of a minimally invasive procedure and surgery is used to optimize the outcomes associated with the CVM.  At UVA, the interventional radiologists work in a multidisciplinary team that includes dermatologists, hematologists, pain management specialists and plastic, orthopedic, and vascular surgeons,

If you or your child has a vascular malformation, talk to your doctor and ask about a referral to the Interventional Radiology team at UVA. You can also directly call the Interventional Radiology Clinic at UVA at +1 (434) 243-0827 and request a consultation with one of the Interventional Radiologists.

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