Why is an arteriovenous fistula in a limb considered life-threatening?

Overload the heart. An AV Fistula is a 'short-circuit' between the arterial and venous systems. In an extremity it can deprive the remainder of the limb of adequate blood flow, causing pain or even tissue loss. The major problem is that AVFs over time tend to shunt more and more blood, causing a marked increase in venous flow back to the heart and potentially causing causing strain or even pump failure.

Related Questions

Why is arteriovenous fistula in a limb life-threatening and therefore requires amputation?

Not likely. most arteriovenous fistulas (AVF) in the limb are small and not life-threatening. The may be congenital, or a result of trauma, surgery or procedures, but, do not often result in amputation. They will usually enlarge if untreated, and this may involve surgery or catheter based procedures depending on the location of the AVF. Read more...