Helpful Terminology

Patients and their families are often confused by terms they have never heard before, particularly when they are under stress from dealing with an unfamiliar medical situation. The following are some of the terms which you may hear, along with a brief definition.


A diagnostic study in which a catheter is threaded through the arterial system and x-ray contrast (dye) is injected to obtain images of the arterial circulation. Usually used in the diagnosis of arteriovenous (high flow) malformations.


Short for Arteriovenous Malformation. Strictly speaking, an AVM is an abnormal connection between arteries and veins (sort of a “short circuit” in the circulation).


An anti-cancer drug which can be injected directly into malformations, acting as a sclerosing agent.


Metallic coils which are placed through a catheter in an artery to mechanically block it.


Some abnormality which is present from birth. Usually not genetically passed on in families (only the specific individual affected).


An antibiotic which can also be used as a sclerosant solution. Most often used in treating lymphatic malformations.


The process of intentionally blocking a blood vessel to achieve a therapeutic result. Various materials can be used, depending on the clinical situation.


The chemical name for an alcohol solution which can be injected into arteries or veins, which causes rapid occlusion due to its chemical toxicity.


An abnormality in the genetic make-up which may be passed on in families through varying patterns of inheritance. Most vascular malformations are congenital but not genetic abnormalities.


Chemically nBCA, a special medical adhesive injected into an artery to form a cast of the vessel. Usually used in the treatment of high flow AVMs.


This term is often incorrectly applied to all vascular birthmarks – it is actually a benign tumor of blood vessels seen in infants and young children that generally gets better by itself (a process called “involution”). It is never seen in adults.

High flow AVM

This is a malformation that consists of arteries abnormally connecting to veins (“shunting”). The flow through the malformation is therefore rapid.

Klippel Trenaunay Syndrome (KTS)

A fairly common type of venous malformation usually involving one limb, usually the leg. The range of severity varies widely but usually includes varicose veins or venous malformations, growth disturbance of the limb, and skin discoloration (“port wine stain”).

Low flow malformation

This type of malformation consists of abnormal veins or lymphatic tissue, which are both low flow vessels.


Used to study the lymphatric system, requiring a small surgical incision in the foot to place a needle in a lymph channel and inject special contrast (ethiodol, an oil which shows up on x-rays).

Lymphatic system

A less familiar part of the circulatory system, consisting of small (almost microscopic) vessels and lymph nodes. This system serves two functions: first, it scavenges tissue fluid from the body and returns it to the main circulation, and second, serves as part of the immune system.


A drug derived from bacterial proteins which has been used in treating lymphatic malformations by causing an inflammatory reaction. Not generally used in the U.S.


Trade name for ethylene vinyl alcohol copolymer, a non-adhesive material injected to block arteries

Osler Weber Rendu Syndrome

Also known as Hereditary Hemorrhagic Telangiectasia (HHT) – a familial syndrome which includes arteriovenous malformations in various parts of the body, including the lung.

Parkes Weber Syndrome

Similar to KTS, but with an arterial (high flow) component.

Port Wine Stain

Port Wine Stains are a type of venous malformation involving the superficial layers of the skin, causing an area of pink to red discoloration. 


Similar to embolization but the abnormal vessels are treated by directly injecting a chemical or drug which intentionally causes inflammation, leading to shrinkage of the abnormal tissue.


Short for Sotradecol (sodium tetradecyl sulfate), a chemical sclerosing agent used in treating venous (low flow) malformations as well as varicose veins.

Sturge Weber Syndrome

A fairly rare genetic disorder which includes specific birthmarks, brain abnormalities, seizures, and cataracts.

Vascular birthmark

A general term usually used to describe a vascular malformation involving the skin and creating a red or purple discoloration.

Vascular malformation

A general term for any congenital abnormality of the blood vessels.

Vascular plug

A metallic mesh device which is passed through a catheter and expands inside an artery to block it; it is detachable, meaning that it can be repositioned or removed the initial placement is suboptimal.


A diagnostic study where a needle or catheter is placed in a vein and contrast injected to obtain images of the veins.