Chronic kidney disease patients who have to undergo haemodialysis will usually do so using their surgically creased arteriovenous fistula. This is the access point for the haemodialysis machine to extract and then return your filtered blood to your body.
The arteriovenous fistula is a surgically created connection between an artery and a vein. Typically it is formed in the arm, either at the wrist or near the elbow, however some people do require their fistula to be formed in the leg in certain circumstances.
The arteriovenous fistula is essentially a shortcut for the blood flow and as a result it develops into a high flow pathway of blood. Usually the artery in the forearm (called the radial artery) will have a blood flow of less than 100ml/min. Once the surgeon has connected the vein to the artery we expect the fistula to “develop”. This means that the size of the vein will increase significantly, usually to a minimum of 5mm, and the amount of blood flow should also increase significantly, ideally to at least 500-1000ml/min.
Use navigation slider to see before and after arteriovenous fistula formation surgery.
LEFT - Before fistula formation RIGHT - After fistula formation
For the surgeon to be able to create a functional fistula it is important to map out the veins and arteries in your arms. They require the vessels to be of suitable quality and size. The sonographer is able to look through the skin and see the vessels inside your arms. They can assess how healthy the arteries and veins are and measure the diameters.
Sometimes you will need to remove your shirt so that the sonographer can check the veins in the entire arm up to your neck. Or if your fistula is in your leg then you will need to remove your trousers/pants. You do not need to remove underwear.
The sonographer will put gel on your arm (or leg) and run the transducer along your arm. They will map the veins and arteries in your arm and draw a diagram with all the information for Dr Theivendran. This scan will usually take around 20 minutes.