Hello everyone!
Does it matter if the avm is formed in veins or arteries in the brain?
Hi Margret,
My understanding is that AVMs are always at the connection BETWEEN arteries and veins... Whereas the veins and arteries are usually connected by a tangle of narrow capillaries, AVMs are a connection made up of a tangle of wide vessels, our surgeon said. The width means that the blood never slows down as it flows through, so this stresses the walls of the vessels and causes ruptures, and the width also diverts blood "traffic" from the rest of the brain, since it's so easy for blood to flow through the AVM instead. Also, the thickness of the vessel walls means that no nutrients escape the blood to nourish that part of the brain. I'm speaking about brain AVMs here, and it might be different with other types. I'd like to be corrected if anyone knows something different!
JH
Hi Margret. A similar subject came up last month. I do not know if this info will help or not. I copied from a post my friend Hanne put out...
Cindy: An arteriovenous fistula (AVF) is a direct connection between an artery and a vein. The blood bypasses the capillaries and tissues, and returns to the heart. Arterial blood has a higher blood pressure than veins and causes swelling of veins involved in a fistula. AVF's are similar to AVM's in that they both disrupt the circulatory cycle.
An AVF is characterized by a single connection between and artery and a vein, whereas an AVM contains multiple arteries and veins.
There are two types of arteriovenous fistulas, congenital and acquired.
A congenital arteriovenous fistula is a rare birth defect that formed during fetal development.
An acquired arteriovenous fistula is one that develops after a person is born. It usually occurs when an artery and vein that are side-by-side are damaged, and the healing process results in the two becoming linked. For example, after catheterizations, arteriovenous fistulas may occur as a complication of the arterial puncture in the leg or arm.
Fistulas also form without obvious cause.
Hope this helped to clarify the difference...Love and peace
hanne xxx
Great explanation. I am finding it difficult to explain to others but your words summed it up beautifully.
JH said:
Hi Margret,
My understanding is that AVMs are always at the connection BETWEEN arteries and veins… Whereas the veins and arteries are usually connected by a tangle of narrow capillaries, AVMs are a connection made up of a tangle of wide vessels, our surgeon said. The width means that the blood never slows down as it flows through, so this stresses the walls of the vessels and causes ruptures, and the width also diverts blood “traffic” from the rest of the brain, since it’s so easy for blood to flow through the AVM instead. Also, the thickness of the vessel walls means that no nutrients escape the blood to nourish that part of the brain. I’m speaking about brain AVMs here, and it might be different with other types. I’d like to be corrected if anyone knows something different!
JH