Background

Question 1

What is the avg age at presentation for arteriovenous malformations (AVMs)?

Answer 1

30 yrs (10–40 yrs)

Question 2

What is the nidus of an AVM?

Answer 2

The nidus is a tangle of abnl arteries/veins connected by at least 1 fistula.

Question 3

What is the main histologic abnormality in the vasculature of an AVM?

Answer 3

Absence of smooth muscle layer; ↑ venous pressure (fibromuscular thickening with incomplete elastic lamina)

Question 4

What are the morbidity and mortality per bleed for AVMs?

Answer 4

Morbidity: 30%–50%/bleed

Mortality: 5%–10%/bleed (1%/yr)

Question 5

What is the rate of hemorrhage per yr for AVMs?

Answer 5

AVMs have a 3% chance of hemorrhage/yr. After an initial hemorrhage this risk increases to 5%/yr.

Question 6

Are most AVM cases familial or sporadic?

Answer 6

Most AVMs are sporadic.

Question 7

What familial/genetic syndromes are associated with AVMs?

Answer 7

Osler–Weber–Rendu (hereditary hemorrhagic telangiectasia) and Sturge–Weber syndromes are associated with AVMs.

Question 8

What characteristics portend an increased risk of hemorrhage from AVMs?

Answer 8

Previous hemorrhage, increased age, aneurysm, deep venous sinus drainage, deep location, single draining vein, and venous stenosis

Question 9

Aneurysms are found in what % of pts with AVMs?

Answer 9

6%–8% of AVM pts harbor aneurysms.