Hello nursestudentumb,

An interesting question.

An AV (arteriovenous) shunt or fistula, is a communication between a vein and artery.  Oftentimes, these are created by vascular surgeons to give end-stage kidney failure patients, i.e. those that require dialysis, access for the large-bore needle required for dialysis. 

Normal veins are often too small in diameter to access for the amount of blood needed to process for dialysis.  By creating the communication, the blood pressure in the vein increases dilating the vein, and creates the blood flow necessary for dialysis.

Blood pressure cuffs, tight-fitting jewelry/clothing, or anything else that restricts blood flow should be avoided because it can increase the chance of forming clotts in the vein.

Hope this helps.

To your health,

Neil MD