Dialysis Access
What is dialysis access surgery?
Dialysis, either hemodialysis or peritoneal dialysis, is a life-saving procedure that replaces kidney function when the organs fail. In order to be treated with dialysis, physicians must establish a connection between the dialysis equipment and the patient's bloodstream.
Dialysis access surgery creates the vascular opening so a needle can be inserted for hemodialysis or an abdominal catheter inserted for peritoneal dialysis.There are several ways to establish dialysis access – arteriovenous fistula, graft or a catheter in a large vein. Your nephrologist (kidney doctor) and surgeon will work with you to decide which type of access will provide you with the best long-term dialysis.
Who performs the dialysis access procedure?
Establishing dialysis access is an invasive (surgical) procedure that can be performed by nephrologists, interventional radiologists and surgeons.
What type of dialysis access procedure is necessary for hemodialysis?
Hemodialysis circulates blood through a machine outside of your body to remove toxins and excess fluid and to correct electrolytes like potassium, sodium, phosphate and calcium, to name a few. The machine then pumps the cleansed blood back into your body. The blood leaves and returns to the body through a catheter, a long piece of silicone tubing placed in the neck, chest or leg. A catheter is used to establish quick vascular (bloodstream) access if you need to begin dialysis therapy immediately. Or dialysis access nurses can access the bloodstream by placing two needles into a fistula or a graft that has been previously created for this purpose.
How are catheters placed?
Catheters come in two varieties, temporary and permanent. Temporary catheters penetrate the skin and directly enter the venous system. Permanent catheters also penetrate the skin, but are then tunneled under the skin for several inches before they finally enter the venous system. Tunneling the catheter reduces the risk of infection.
Any medical professional can place a temporary catheter using a local anesthetic and minimal sedation to help with minor discomfort. However for placement of permanent catheters, a surgeon in the operating room, or an interventional radiologist in the interventional suite is necessary. During the procedure, physicians use fluoroscopy (continuous X-rays) to be sure the catheter is positioned correctly. Permanent catheters require a minor procedure for removal whereas temporary catheters can simply be pulled out.
Are catheters safe for long-term use?
Prolonged catheter access can lead to complications, the most common of which is infection. Even with excellent placement technique, bacteria can enter the bloodstream through the catheter during dialysis. Bacteria from the skin can also move down the catheter and enter the bloodstream. With catheter infection people develop fever and chills and need prompt treatment. Often, the catheter must be removed so the body can fight the infection. Another possible complication from long-term catheter use is damage to the main veins in the chest, which can lead to stenosis (narrowing) or thrombosis (clotting) of the veins. This type of damage may becomepermanent and the vessel - as well as the arm on the side of the vessel - may no longer be useable for dialysis access.
Because of these potential complications, physicians make every effort to avoid prolonged catheter use, if possible.
What is an AV fistula?
The best way to establish long-term hemodialysis access is to construct an arteriovenous (AV) fistula. An AV fistula is a surgically placed "shunt"; that is, an artery is directly sutured to a vein. An artery is a high-pressure vessel that carries blood away from the heart and delivers nutrients and oxygen to the tissues. A vein is a low-pressure vessel that returns blood back to the heart to begin the process all over again. When an artery and a vein are sewn together, some of the high-pressure blood does not reach the tissues but is diverted instead into the vein and back to the heart. Over time the vein will dilate, carry more blood and become stronger, a process that is often called maturation. At maturation, nurses can easily access the vein with needles for dialysis therapy.
Where are AV fistulas located and how long do they last?
Surgeons can create an AV fistula in your wrist, forearm, inner elbow or upper arm. When properly constructed, and with satisfactory maturation, an AV fistula can function for many years.
How is the AV fistula procedure performed?
A surgeon usually performs the procedure in the operating room. You receive a local anesthetic (numbing medicine) at the proposed site along with intravenous (IV) sedation to relax you. Discomfort is minimal and you may even fall asleep during the 1 to 2 hour-long procedure. The surgical incision is usually only 2 to 4 inches long. Generally you are able to return home later that same day. The fistula usually requires from 8 to 12 weeks for the veins to dilate prior to initial use.
Despite excellent technique, some patients may suffer complications from the AV fistula procedure. Infection, bleeding, arm swelling and/or tingling in the fingers may occur postoperatively. An unusual, but serious, complication can occur when too much of the arterial blood that is supposed to reach the hand is redirected through the fistula. Sometimes the fistula functions so well that not enough blood reaches the hand causing ischemia (lack of oxygen). This condition is called "steal" and usually requires surgical procedure to establish a new access at a different site.
Can anyone have an AV fistula?
Unfortunately not every patient is suitable for an AV fistula. Numerous needle sticks for IV fluids, blood work and/or medicines can damage veins over time, creating scar tissue, which can make creation of an AV fistula impossible. If the veins are damaged or too small, the AV fistula will not mature, or worse yet, clot. In this situation, the dialysis access team recommends other options that may include another fistula at a different site, catheter placement or an arteriovenous graft.
What is an arteriovenous graft?
An arteriovenous graft is another form of dialysis access, which can be used when people do not have satisfactory veins for an AV fistula. In this procedure, surgeons connect an artery and a large vein in your elbow or armpit using a graft made of synthetic fabric that is woven to create a watertight tube. The graft is frequently used to repair blood vessels or perform blood vessel bypass when blockages occur, and also works very well to establish dialysis access.
How is the AV graft created?
Creating an AV graft is a surgical procedure, which requires a small incision at the proposed site. Surgeons sew the graft to an artery and tunnel it, just under the skin, creating a loop back to the starting incision where it is then sewn to a vein. The long loop gives the dialysis nurses space to access the graft. AV grafts can be safely used in about two weeks, as no maturation of the vessels is necessary.
Grafts have a lifespan of approximately 2 to 3 years but can often last longer. However, AV grafts can be more troublesome than AV fistulas. Blood is more likely to clot in grafts because they are made of prosthetic (foreign) material. When this happens, interventional procedures can remove the clot and restore blood flow for dialysis. Complications related to AV grafts are similar to those with AV fistulas: bleeding, thrombosis (clotting), steal and because of the prosthetic nature of the graft, infection. Infected grafts often need tobe removed immediately and a new access site developed once the infection clears.
What type of dialysis access procedure is necessary for peritoneal dialysis?
Surgeons must place a long silicone-based tube called a Tenckhoff catheter into the abdomen before peritoneal dialysis can begin. The surgeon in the operating room positions the tube using a local anesthetic and IV sedation. Making a small incision in your abdomen, the surgeon advances the tube deep into the lower part of your peritoneal cavity (the membrane lining the inside of the abdomen), tunnels the tube under the skin for several inches, brings the tube up through the skin at a different location, and then surgically closes the initial incision.
A sterile dressing covers the catheter that remains outside of the body. Tunneling the catheter reduces the likelihood of infection in the peritoneal cavity. You may be allowed to go home the same day of surgery. Peritoneal dialysis can begin when the incisions heal, usually about 2 to 4 weeks after the access surgery.
What types of complications are possible from the Tenckhoff catheter?
Complications related to catheter placement may include bleeding, and rarely, damage to large or small intestines or abdominal blood vessels. Although unusual, these issues could require additional corrective surgery. Once peritoneal dialysis begins, complications related to repeated use of the catheter include peritonitis, which is an infection of the peritoneal cavity. Peritonitis, which can be quite serious, is usually associated with abdominal pain, fevers and cloudy peritoneal dialysis solution. Such infections usuallyrespond to antibiotic treatment, but if they don’t, then it may be necessary to remove the catheter.
When should dialysis access surgery take place?
The best approach is to undergo dialysis access surgery well before dialysis therapy needs to begin, which will give the access site time to mature and avoid the use of temporary catheters. You may need a temporary catheter while you are waiting for your permanent AV fistula or AV graft to heal and mature.
How are individuals evaluated for long-term dialysis access success?
A physician typically performs an extensive physical exam to identify satisfactory vessels to construct the AV fistula or graft. The evaluation may also include additional studies such as ultrasounds or even dye studies of the blood vessels in your arms and legs. After the appropriate type of access is determined, the location is selected. Typically surgeons construct hemodialysis access in the forearm of your non-dominant hand. If this site is not suitable then the surgeon may choose to use the forearm of the dominant hand or the upper arm, above the elbow.
Where can I get more information?
Your nephrologist or Advanced Vascular Care Center physician can provide more information.
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