What is renal failure?
Patients whose kidneys fail require either renal transplantation, peritoneal dialysis through the abdomen or alternatively haemodialysis where the blood is filtered by a dialysis machine (artificial kidney). Haemodialysis requires large volumes of blood so reliable access to the vascular system is critical. This can be achieved using a plastic tube (catheter) placed into a large vein usually in the neck. However, this is not a permanent solution as they can become infected or blocked and can cause damage to the veins.
What is the best option if I need haemodialysis?
Patients requiring long term haemodialysis are best served with an arteriovenous fistula. These are surgically created by joining an artery to a vein, usually at the wrist or the elbow. After the operation and over a period of 6 to 12 weeks the blood flow through the fistula increases to the point where there is enough flow to support haemodialysis. Once this is the case the fistula can be accessed with needles through the skin and into the vein. Blood is then filtered via a dialysis machine.
When should I have my fistula created?
Ideally a fistula is created before a patient requires dialysis so that it is ready to use, and a catheter can be avoided. Patients should caution Doctors to avoid placing intravenous lines into the veins at the wrist and elbow to avoid damage to these veins. The non-dominant arm is the preferred location for the fistula to allow greater freedom on dialysis or to facilitate patients dialysing themselves when they are on haemodialysis at home although this cannot always be achieved.
Which is better, a fistula or a synthetic graft?
Ideally a patient’s own veins are used to create an arteriovenous fistula. In patients whose veins have been damaged or are not suitable, a synthetic graft can be placed under the skin as an alternative. These grafts have more complications than using a patient’s own veins and typically do not last as long. An ultrasound is used to confirm if a patient’s own veins are suitable and the best area on the arm to create a fistula.
What happens after I have a fistula created?
Fistulas can have problems. They may not mature to the point where they can be used therefore some patients may require further procedures. Established fistulas used for dialysis can develop narrowing that may limit blood flow and fistulas may block. Ultrasound surveillance is used to identify issues early so that they can be addressed, and fistula flow maintained. Fistulas can also divert blood flow away for the hand causing pain, if this is the case the fistula may need to be removed in order to restore the circulation to the hand.
How is the fistula used for haemodialysis?
Placing the needles into fistulas should be performed by someone appropriately trained (including possibly the patient) under strict hygiene conditions to prevent infection. The buttonhole technique, where the needle is inserted at the same site for each dialysis, is less painful but it can cause local fistula destruction. Area puncture, where the fistula is needled over a specific area, results in the vein expanding over the area and it can also cause narrowing between the expanded areas. The rope-ladder technique, where needles are inserted for each dialysis by moving along the fistula in a sequential pattern, is usually the best technique to prevent fistula destruction.
Sydney Vascular Ultrasound provides specialised vascular and venous diagnostic imaging in Burwood, Bankstown and Liverpool.