What is an aorta venous malformation?

AVM: i think you must mean arteriovenous malformation. This represents a tangle of small arteries that become small veins. The significance is that they are prone to bleeding. They can be found in the brain, in the esophagus, the stomach, the liver, the small bowel, and the colon to name a few.

Connection: This is a genetic abnormality that allows an artery to feed directly into a vein (instead of gradually perfusing tissue before being returned to the venous capillaries). This direct A-V communication creates what is called a shunt, and if large enough may cause volume overload on the heart, which may lead to hear chamber enlargement and even failure. At the site of the AVM, bleeding may result.