What is a Vascular Malformation?

Vascular malformation is a general term that includes congenital vascular anomalies of only veins, only lymph vessels, both veins and lymph vessels, or both arteries and veins.

• Only veins: venous malformation (VM)
• Only lymph vessels: lymphatic malformations (LM)
• Both veins and lymph vessels: venolymphatic malformations (VLM)
• Arteries connected directly to veins without any capillaries in between: arteriovenous malformation (AVM)

Why Do Vascular Malformations Occur?

We are just beginning to understand how malformations occur, but we do know that they are present at birth and become apparent at different ages. The pulmonary arteriovenous malformation, when associated with Hereditary Hemorrhagic Telangiectasia (HHT), is inherited genetically. Work is currently being done on the possible genetics of other malformations. Most are only known as something that occurs during development of the arteries, veins, and/or lymph vessels, but without specific cause.

What are the Symptoms of a Vascular Malformation?

Vascular malformations can cause a variety of symptoms depending on the location in the body. Venous malformations may cause pain wherever they are located. Venous and lymphatic malformations may cause a lump under the skin. There may be an overlying birthmark on the skin. Bleeding or lymph fluid leaking may occur from skin lesions. Lymphatic malformations tend to become infected, requiring repeated antibiotic treatments.

Arteriovenous malformations may cause pain. They are also more stressful on the heart because of the rapid shunting of blood from arteries to veins. Depending on their location, they may also result in bleeding (for example from the bowels, from the uterus or from the bladder).

Hemangioma is another common term used for vascular anomalies. However, this name actually applies to a childhood vascular anomaly that has a rapid growth phase between birth and 3 months of age. These will resolve completely by age 7. The major reason for us to treat these is for low platelets that do not respond to medical treatment, or in the liver because of massive shunting with a strain on the heart.

Pulmonary arteriovenous malformations (PAVMs) are different in that they shunt blood from the right heart system to the left heart system without picking up oxygen in the lungs. This results in symptoms of low oxygen, shortness of breath, fatigue. These malformations may also bleed, resulting in coughing up blood or blood in the chest. Also, these pulmonary artery to pulmonary vein shunts can allow clots to pass through the lungs and travel to the arteries in the body, with risk for stroke or brain abscess.

How are Vascular Malformations Treated?

Although surgery is sometimes useful, it is usually difficult for surgeons to completely remove vascular malformations, which will return if not removed completely. A nonsurgical method of closing down the blood or lymph flow into the malformation is done by vascular and interventional physicians, who treat patients with image guided procedures. Vascular malformations are treated by embolization. The AVMs and hemangiomas can be closed by advancing a tiny plastic tubing, no larger than a pencil point, into the feeding artery to the malformation. This can be done without incisions or stitches, and with only mild sedation. Medical glue or alcohol or small beads are then floated into the malformation until it is full and no longer has blood flowing through it. For Pulmonary AVMs platinum coils are used to block flow through the feeding artery to the malformation. The VMs and LMs are closed by injecting alcohol into the sacs filled with venous blood or lymph until these sacs collapse and no longer fill.

How Effective is the Treatment?

Pulmonary arteriovenous malformations are very effectively treated by embolization which blocks only the abnormal artery feeder, and preserves the normal lung arteries. Embolization techniques have been used extensively all over the world for the past 30 years and have been well established for many years, and have proved invaluable in treating vascular malformations.

Patients usually notice an immediate improvement in symptoms with the immediate increase in oxygen level. Other arteriovenous malformations are more difficult to treat since they tend to pull in new artery feeders from time to time. However, embolization is very effective in blocking abnormal artery feeders while preserving normal arteries. AVMs may require a series of treatments to block all of the abnormal feeders. Venous and lymphatic malformations respond well to alcohol embolization. These may also require a series of treatments about six weeks apart to block all of the abnormal vessels.

Post Procedure & Follow Up

Treatment of arteriovenous malformations can can involve same day discharge or a one-night hospital stay. There is usually minimal discomfort for one to three days. Malformations swell after treatment with alcohol, and the swelling and pain may last for three to five days. During this time, we give patients medication for any pain or swelling they may have. The full shrinkage of these malformations may take four to six weeks.

All vascular malformations require long term surveillance, so that if there is any change, such as a growth spurt with puberty or pregnancy or menopause, they can be monitored for symptoms that may warrant rechecking and possibly retreating. We monitor PAVMs over time to be sure they collapse and do not refill.