The following information is to help you, as a patient with kidney failure, understand the issues regarding surgery to have long-term dialysis access. If you are being referred to see a vascular surgeon for dialysis access, it is either because your kidneys are no longer functioning adequately, in which case you are already getting dialyzed, or your renal (kidney) function is so marginal, that it is likely you will need dialysis in the near future.
Dialysis can be performed through two routes: 1) Hemodialysis and 2) Peritoneal dialysis. This following information refers to hemodialysis only. Hemodialysis means that the body is cleansed by a filter in the hemodialysis machine and for that machine to be able to do this successfully, it requires circulation at a high flow rate through the machine.
Tunneled catheters are best considered a bridge to permanent hemodialysis access. This involves a catheter that is placed into a vein in the neck and is called a “tunneled catheter” because it is tunneled under the skin. Although this is effective and useful, these catheters should be only used for as short a time as possible. The longer these catheters are in place, the higher the risk of the vein being narrowed and also of infections of the bloodstream.
Permanent hemodialysis access can be either an arteriovenous fistula or graft.
Arteriovenous Fistula
The arteriovenous fistula is the most durable option because, if it matures successfully, it lasts much longer than a ateriovenous graft does. The fistula is a connection of the vein to the artery directly. Your vein must be of good quality, meaning that it must be a certain size and character. To get an idea of the best vein, we routinely obtain an ultrasound of the veins, which gives us a good idea of the best veins to use. After the operation is done, the vein needs to mature – that is, it needs to get bigger in size and thicker before it can be successfully used for dialysis.
There are different ways for a fistula to be created and the details are not important. It is important to know that sometimes, many of the veins that we would use are damaged or clotted because of previous punctures or intravenous lines. In that case, we may be able to use a vein that runs on the inner side of the arm, called the basilic vein. If we do use this vein, it will require two operations. This is because the basilic vein runs deep under the skin and for it to be usable, we have to raise it closer to the skin surface. We prefer to do this in two operations.
In either case, the vein will need a minimum of 8-12 weeks to get big and thick enough to be used for dialysis. For this reason, it is great if your nephrologist (kidney doctor) refers you to a vascular surgeon before you actually need dialysis. If you have your fistula early enough, hopefully it will be mature by the time you do need dialysis, and you never will need to have a tunneled catheter placed.
Arteriovenous Graft
If your veins are not of good quality, you may need to have an arteriovenous graft placed. This is a synthetic (Teflon) graft connecting the artery to the vein. The advantage of this is that it can be used in as early as two weeks. The disadvantage is a graft does not last as long as a fistula; half of these grafts will clot off in the first year. For this reason, we attempt a fistula whenever possible, since they last much longer.
Operation & Recovery
We perform this operation under local anesthesia with sedation in over 90% of cases. The operation typically takes about two hours. After recovering in the recovery room, the patient can go home. There will be a sterile, transparent dressing on the incision. The dressing can be taken off at home after 72 hours and the incision left uncovered. It is okay to shower normally with the uncovered incision. The stitches are absorbable and will not need to be removed. You will be seen in the clinic approximately 2 weeks following surgery.
Potential Risks
As with any intervention or operation, one has to be aware of the risks of the operation. The risks of anesthesia are minimized, due to the fact that this is under local anesthesia with sedation; but the risk is not zero. There is always a possibility of the fistula or graft clotting, but the risk is lower with a fistula than a graft.
Sometimes, particularly in diabetic patients, the fistula can “steal” blood away from the hand. If this happens, one has to watch for hand or finger pain, numbness and tingling, and in the worst situations, a reduction in the strength and/or sensation in the hand. If these symptoms occur, it is important for you to let the surgeon know about it. It may occasionally require additional surgery to prevent the symptoms from worsening, and in the extreme circumstance, it may require tying off the fistula or the graft.
The other potential risk is that one can develop an infection in the skin, which is most times easily treated with antibiotics. Rarely, months or years later the graft can get infected, in which case it has to be removed. The risk of this is much lower with a fistula than with a graft.
It is important to realize that the term permanent dialysis access is not accurate because many times patients with renal failure will require an additional operation or operations. However, if one has a functioning fistula, the chance of this is much lower than with a graft. With advanced planning, however, a good functional access can be obtained in the majority of patients.