The AVM medical abbreviation stands for arteriovenous malformation, an abnormal tangle of blood vessels where arteries connect directly to veins without the usual network of tiny capillaries in between. AVMs can form in the brain, the spinal cord or elsewhere in the body.
Most people with an AVM were born with it, and many learn about it only from a scan done for another reason. In other cases it is found after a headache, a seizure or a bleed. You will see the term in neurology, neurosurgery and radiology notes, and the plural AVMs when more than one is present. This page explains the meaning, how scans describe an AVM, and the terms most often confused with it.
At a glance
What the AVM medical abbreviation describes
Normally, blood flows from high pressure arteries into a fine mesh of capillaries, where oxygen passes into tissue, and then drains into low pressure veins. In an AVM, a knot of abnormal vessels called the nidus links arteries straight to veins. Blood rushes through at high pressure, and the veins that drain it can stretch and weaken.
The word breaks down simply: arterio for artery, venous for vein, and malformation for something formed abnormally. Many AVMs never cause trouble. Others can bleed, press on nearby tissue, or divert blood away from healthy areas.
How AVMs are described on scans
Imaging reports usually say where the AVM sits, how big it is, and whether it has bled.
| Phrase | Meaning |
|---|---|
| Nidus | The central tangle of abnormal vessels |
| Feeding arteries | Arteries that supply the AVM |
| Draining veins | Veins that carry blood away, described as deep or superficial |
| No evidence of hemorrhage | No sign of bleeding on this scan |
| Grade | A score that helps estimate surgical risk, based on size, location and drainage |
Consult line: "Unruptured R frontal AVM, grade II, discussed observation versus treatment." The AVM has not bled, sits in the right frontal lobe, and the team is weighing whether to treat it or watch it.
AVM versus look alike vascular terms
- AVF: arteriovenous fistula, a single direct connection between an artery and a vein. Dialysis access is a surgically made AVF.
- Aneurysm: a bulging, weakened spot in one artery wall, not a tangle.
- Cavernous malformation: a cluster of slow flow, thin walled vessels, sometimes called a cavernoma.
- SAH: subarachnoid hemorrhage, a type of bleed that an aneurysm or, less often, an AVM can cause.
The diagnosis abbreviations hub lists more vascular and neurologic shorthand in one place.
Treatment words you may see
Notes about AVMs often name one or more treatment approaches. Microsurgery means removing the AVM through an opening in the skull. Embolization means a catheter is threaded through the arteries to plug feeding vessels from the inside, often done by interventional radiology. Stereotactic radiosurgery uses focused radiation to close the vessels gradually over time. Some AVMs are simply watched with repeat imaging.
The choice depends on the AVM's size, location, drainage pattern and whether it has bled, along with the person's age and health.
Questions to ask about an AVM
- Where exactly is it, and has it ever bled?
- What are the options, including watching it?
- Which symptoms should prompt urgent care?
- How often will I need follow up imaging?
This page offers general background on a vascular term. A neurologist, neurosurgeon or your own physician can explain what an AVM finding means for you.
Frequently asked questions
What does AVM stand for in medical terms?
AVM stands for arteriovenous malformation. It is an abnormal tangle of vessels where arteries connect directly to veins, skipping the capillaries that normally sit between them.
What is the difference between an AVM and an aneurysm?
An AVM is a tangle of abnormal connections between arteries and veins. An aneurysm is a bulge in the wall of a single artery. Both can bleed, but they are different structures.
Are AVMs present from birth?
Most are thought to form before birth, although they may not cause symptoms or be found until later in life.
Is an AVM the same as an AVF?
No. An AVF is a single direct link between one artery and one vein, while an AVM is a tangle of many abnormal vessels. Dialysis access is a planned AVF made by a surgeon.