An arteriovenous malformation (AVM) is a condition where arteries connect directly to veins, bypassing the normal capillary system. This causes blood to flow very fast through the vessels. In an AVM, the capillaries are missing or replaced by larger channels connecting the arteries and veins. This direct connection, called a shunt, reduces blood supply to surrounding tissues and increases blood pressure in the veins. Treatment options for AVM include embolization, surgery, and sclerotherapy to remove or block the abnormal vessels. Facial AVM can cause disfigurement and risks include regrowth after treatment and damage to nearby nerves. While asymptomatic AVM may require no treatment, untreated AVM are at risk of

1. Facial Arteriovenous
Malformations

2. What is an Arteriovenous Malformation (AVM)?
 Normally, arteries carry blood with oxygen from the heart to
the brain and body.
 Veins carry blood with less oxygen back to the heart.
 Capillaries connect arteries to veins.
When an arteriovenous malformation (AVM) occurs, the
capillaries are missing. The arteries connect directly to the
veins. This causes the blood to flow very fast through these
large vessels. (Children’s Hospital of Wisconsin, n.d.)

3. What happens in normal tissue?
 The circulation in the normal tissue consists of
arteries, capillaries, and veins.
 The capillaries are tiny channels throughout every
tissue of the body that carry arterial blood with its
oxygen and nutrients to the cells of the body.
 After passing through capillaries, blood is collected
by veins.
 The blood pressure in the normal veins is much
lower than the blood pressure in the
arteries. (Butterfly AVM Charity, n.d.)

4. What happens in an AVM
 In an arteriovenous
malformation, some of the capillaries
are replaced by larger channels that
connect the arteries directly to the
veins.
 The direct connection is called a shunt
because it shunts, or diverts, the blood
from the artery directly to the
vein, bypassing the capillaries.
 The channels between the artery and
vein are termed the nidus. The nidus
can consist of a vast number of tiny
shunts, or a smaller number of large
arteriovenous shunts (Butterfly AVM
Charity, n.d.).

5. What happens in an AVM Cont.
 The number of arteries supplying an AVM and the number of
veins draining it are quite variable.
 In a peripheral arteriovenous malformation, the shunt has the
effect of reducing the blood supply with its nutrients and oxygen
to the tissue around it, raising the blood pressure in the draining
veins, and increasing the amount of blood that is pumped through
the arteries and veins.
 In time, the shunting through a peripheral AVM damages the
surrounding tissue and increases the work done by the heart.
(Butterfly AVM Charity, n.d.)

6. Some AVM Facts
 What causes an AVM to form is not understood
 AVM’s are rare
 Intercranial (brain) AVM is most common, extremity
(peripheral) AVM less common
 AVM’s are frequently misdiagnosed as other types of
vascular malformations like hemangioma or CM
 An extensive AVM may cause increased cardiac
output (Marler, Mulliken, 2005).

7. What does an AVM look like?
 At birth, the skin on top of the AVM may be pink or
red. Over time the skin will look dark red or purple.
 It may be a small area such as a lip, or it may take
up an entire arm or leg. The skin over the
malformation usually feels warmer than other skin.
A pulse from the heartbeat may be felt.
 AVMs are most common in the head but may
appear anywhere on the body or internal organs.
(Children’s Hospital of Wisconsin, n.d.)

8. What causes it?
 The cause of an AVM is not known. They may have a
genetic link. They are present at birth
(congenital), but less than half are diagnosed at
birth. It may take years to be diagnosed. (Children’s
Hospital of Wisconsin, n.d.)

9. How is it diagnosed?
 The diagnosis must be
confirmed by an MRI or a CT
scan. Scans must be done to see
how big the malformation is.
(Children’s Hospital of
Wisconsin, n.d.)

10. What are the complications?
 Crusting and bleeding on the skin.
 Pain.
 Severe bleeding (hemorrhage).
 Headaches and other symptoms if the AVM is in the
head.
 Heart failure may develop due to the large amount of
blood that flows through the AVM . (Children’s
Hospital of Wisconsin, n.d.)

11. How is it treated?
 Embolization. Tiny particles or coils are injected into
the malformation. This slows the flow of blood in the
AVM. Embolization is usually done before surgery to
help decrease the blood loss during surgery.
 Surgery. Surgery will remove as much of the AVM as
possible. Several surgeries may be needed to remove the
entire AVM.
 Sclerotherapy. A chemical is injected into a blood
vessel. This will cause the inside of the vessel to swell so
blood cannot flow through it. The vessel will then
collapse and form scar tissue. (Children’s Hospital of
Wisconsin, n.d.)

12. What other syndromes that are linked to AVMs?
 Some AVMs may be linked to a group of problems
called a syndrome. A doctor will ask you questions
about the family health history.
 The syndromes linked to AVMs are Bannayan-RileyRuvalcaba syndrome, Cowden syndrome and ParkesWeber syndrome. (Children’s Hospital of
Wisconsin, n.d.)

13. What about facial AVM’s?
 Some AVMs have no symptoms and may go
undetected.
 Some AVM’s remain stable throughout life
 Enlargement may occur in response to trauma or
hormonal disturbances during puberty or pregnancy
 Treatment of AVMs can be difficult, as
frequently, following an apparently successful
extirpation, there is regrowth of the tumor to a size
larger than its original size, often with supply by
surgically inaccessible vessels.(P. S. Bhandari, 2008)

14. More about Facial AVM’s
 AVM’s affect less than 1% of the population. Facial




AVM’s are more rare. Because of this, there are few
doctors treating facial AVM’s.
Depending on the size and location of the facial
AVM, there is a higher chance that it will regrow
aggressively following resection.
AVM’s of the face can cause large growth of
tissue, disfigurement, changes of the skin, pain and
ulcerations.
Bleeding is sometimes a problem.
AVM’s growths can cause damage to the surrounding
tissue

15. Risks of AVM treatments
 Resection and embolization procedures in the face
may run the risk of temporary or permanent
paralysis. AVM’s in the face are sometimes near or
wrapped around facial nerves. These may be come
injured or damaged during treatment.
 Some treatments may result in some ischemia or
necrosis.
 In large, progressed AVM’s resection can be risky
due to the risks of bleeding.

16. Risks of not treating AVM’s
 Sometimes AVM’s are asymptomatic and require no
treatment.
 AVM’s that are growing will continue to grow if left
untreated . Health risks increase as the AVM grows.
 AVM’s that are large may become at risk for
rupture, cardiac failure and death.

17. Terminology
 Lesion – Damaged tissue
 Nidus – Central part of AVM tissue
 Shunt – Connection between the artery and the vein
 Bruit – The sound blood makes when it rushes past
obstruction
 Ischemia – Decrease in blood supply to organ or
tissue because of obstruction or constriction of blood
vessels
 Necrosis – Death of body tissue from lack of blood
flow

18. Schobinger’s Clinical Staging System
Stage I: pink-bluish stain, warmth, and Artriovenous
shunting by way of Doppler exam
Stage II: same as stage I, plus
enlargement, pulsations, thrill, bruit and
tense/tortuous veins
Stage III: same as stage II, plus dystophic skin
changes, ulceration, tissue necrosis, bleeding or
persistent pain
Stage IV: same as stage III, plus cardiac failure