Hemodialysis Fistula/Graft Angiography/Maintenance
Specialized Care for Patients With Kidney Disease
Hemodialysis is a method of routing blood through a dialysis machine, which filters the blood, removing waste. It is a lifeline for most patients with renal failure. It can be performed via a central venous catheter or an access circuit (fistula or graft). Our vascular and interventional physicians are specialists in dialysis maintenance and the areas of the body affected by the treatment. We also play an important role in maintenance of an established dialysis circuit by treating narrowed segments with angioplasty balloons and stents, thereby extending the longevity of the access for dialysis. For access to clotted areas, our physicians can restore blood flow through the circuit via a declot procedure.
Dialysis Access Management Procedures
For patients who need dialysis, there are several ways to access the bloodstream so the blood can be cleaned by a dialysis machine. Our physicians work closely with each patient to determine which technique will work best for his or her needs.
A dialysis graft is created surgically in the arm or groin by connecting an artery to a vein with a tube made of woven plastic. After a month, the graft can be accessed with two needles at dialysis. While the graft is healing, most patients will need a catheter to receive dialysis. Grafts have lower infection rates than catheters, especially in the last two to three years before clotting off.
A dialysis fistula is created surgically in the arm by connecting an artery directly to a vein without the use of any plastic graft material. The vein near the connection to the artery will enlarge over the course of a month before it becomes big enough to access with needles at dialysis. While the fistula is maturing (enlarging), patients will typically need a dialysis catheter to receive dialysis. In some cases, the vein does not enlarge on its own and must be opened using balloon angioplasty. Although fistulas are more difficult to create, they can last up to 10 years. For this reason, a dialysis fistula is preferred over a dialysis graft or tunneled dialysis catheter.
A dialysis catheter comprises two plastic tubes that are joined together where they enter the body, in the neck or the groin. When the catheter is hooked up to the dialysis machine, one of the tubes is used to remove "dirty" blood from the body and the other tube is used to return "clean" blood back into the body. Catheters are not ideal for long-term dialysis because of the risk for infection and blockage of the vein. Dialysis catheters are used only when other methods are not possible because they have a higher rate of infection than dialysis fistulas or grafts. Most central venous catheters are placed with image guidance. Our vascular and interventional physicians offer placement of central venous lines for both routine initiation of dialysis and complex situations in which other access methods are not possible. Recanalization of occluded veins might be offered as a last resort.
When a dialysis fistula or graft cannot supply the dialysis machine with a high enough flow rate to clean the blood, a fistulogram can be performed. In this procedure, IV contrast is injected through the graft to identify areas where the blood vessel is narrow. Once these narrowed areas are located, a small balloon is inserted into the fistula or graft and expanded to widen the blood vessel. This process is called balloon angioplasty. If angioplasty does not improve the narrowing, a metallic stent can be placed. Stents are small, metallic tubes that are used to hold the blood vessel open.
When a fistula or graft becomes completely clotted off, a declot procedure can help. We access the clotted graft and inject contrast solution to see the extent of the clot formation. We can then use several technologies to remove the clot from the clotted graft or fistula. Once the clot is removed, usually a narrowing can be identified that caused the access to clot. We usually treat this narrowing with angioplasty or stenting. If a fistula or graft clots off repeatedly in a short time, we can place a dialysis catheter to create a new access point.
Prior to Your Procedure
Prior to a dialysis maintenance procedure, our team will explain how to prepare for the treatment. Avoid eating or drinking anything eight hours before the scheduled procedure, and take any necessary medications with a small sip of water. Dialysis maintenance procedures are done with relaxing medications through an IV. The medications make patients feel relaxed and drowsy, but they are not totally asleep and do not need a breathing tube.