What is dialysis access surgery?
Dialysis, either hemodialysis or peritoneal dialysis, is a life-savingprocedure that replaces kidney function when the organs fail. In order tobe treated with dialysis, physicians must establish a connection betweenthe dialysis equipment and the patient's bloodstream. Dialysis accesssurgery creates the vascular opening so a needle can be inserted forhemodialysis or an abdominal catheter inserted for peritoneal dialysis.
There are several ways to establish dialysis access. Your nephrologist(kidney doctor) and surgeon will work with you to decide which type ofaccess will provide you with the best long-term dialysis.
Who performs the dialysis access procedure?
Establishing dialysis access is an invasive (surgical) procedure that canbe performed by nephrologists, interventional radiologists and surgeons. Ateam effort helps ensure excellent patient service, care and long-termresults. The dialysis access center at BIDMC is staffed with leadingnephrologists, interventional radiologists and transplant surgeons in theBoston community. The team also consists of a dialysis access nursecoordinator and social workers. We meet regularly to ensure that youreceive the best care each specialty has to offer.
What type of dialysis access procedure is necessary for hemodialysis?
Hemodialysis circulates blood through a machine outside of your body toremove toxins and excess fluid and to correct electrolytes like potassium,sodium, phosphate and calcium, to name a few. The machine then pumps thecleansed blood back into your body. The blood leaves and returns to thebody through a catheter, a long piece of silicone tubing placed in theneck, chest or leg. A catheter is used to establish quick vascular(bloodstream) access if you need to begin dialysis therapy immediately. Ordialysis access nurses can access the bloodstream by placing two needlesinto a fistula or a graft that has been previously created for thispurpose.
How are catheters placed?
Catheters come in two varieties, temporary and permanent. Temporarycatheters penetrate the skin and directly enter the venous system.Permanent catheters also penetrate the skin, but are then tunneled underthe 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 localanesthetic and minimal sedation to help with minor discomfort. However forplacement of permanent catheters, a surgeon in the operating room, or aninterventional radiologist in the interventional suite is necessary. Duringthe procedure, physicians use fluoroscopy (continuous X-rays) to be surethe catheter is positioned correctly. Permanent catheters require a minorprocedure for removal whereas temporary catheters can simply be pulled out.
Are catheters safe for long-term use?
Prolonged catheter access can lead to multiple complications, the mostcommon of which is infection. Even with excellent placement technique,bacteria can enter the bloodstream directly through the catheter duringdialysis. Bacteria from the skin can also move down the catheter and enterthe bloodstream. With catheter infection people develop high fevers andchills and need prompt treatment. Generally physicians must remove thecatheter so the body can fight the infection.
Another possible complication from long-term catheter use is damage to themain chest vessels, which can lead to stenosis (narrowing) or thrombosis(clotting) of the veins. This type of damage is usually permanent and thevessel - as well as the arm on the side of the vessel - may no longer beuseable for dialysis access.
Because of these potential complications, physicians make every effort toavoid prolonged catheter use.
What is an AV fistula?
The best way to establish long-term hemodialysis access is to construct anarteriovenous (AV) fistula. An AV fistula is a surgically placed "shunt";that is, an artery is directly sutured to a vein. An artery is ahigh-pressure vessel that carries blood away from the heart and deliversnutrients and oxygen to the tissues. A vein is a low-pressure vessel thatreturns blood back to the heart to begin the process all over again.
When an artery and a vein are sewn together, the high-pressure blood doesnot reach the tissues but is diverted instead into the vein and back to theheart. Over time the vein will dilate, carry more blood and becomestronger, a process that is often called maturation. At maturation, nursescan 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 orupper arm. When properly constructed, and with satisfactory maturation, anAV fistula can function for many years.
How is the AV fistula procedure performed?
A surgeon usually performs the procedure in the operating room. You receivea local anesthetic (numbing medicine) at the proposed site along with IVsedation to relax you. Discomfort is minimal and you may even fall asleepduring the 1 to 2 hour-long procedure. The surgical incision is usuallyonly 2 to 4 inches long. Generally you are able to return home later thatsame day. The fistula usually requires from 8 to 12 weeks for the veins todilate prior to initial use.
Despite excellent technique, some patients may suffer complications fromthe AV fistula procedure. Infection, bleeding, arm swelling and/or tinglingin the fingers may occur postoperatively. An unusual, but serious,complication can occur when the arterial blood that is supposed to reachthe hand is redirected through the fistula. Sometimes the fistula functionsso well that not enough blood reaches the hand causing ischemia (lack ofoxygen). This condition is called "steal" and usually requires surgicalprocedure 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. Numerousneedle sticks for IV fluids, blood work and/or medicines can damage veinsover time, creating scar tissue, which can make creation of an AV fistulaimpossible. If the veins are damaged or too small, the AV fistula will notmature, or worse yet, clot. In this situation, the dialysis access teamrecommends other options that may include another fistula at a differentsite, catheter placement or an arteriovenous graft.
What is an arteriovenous graft?
An arteriovenous graft is another form of dialysis access, which can beused when people do not have satisfactory veins for an AV fistula. In thisprocedure, surgeons connect an artery and a large vein in your elbow orarmpit using a graft made of synthetic fabric that is woven to create awatertight tube. The graft is frequently used to repair blood vessels orperform blood vessel bypass when blockages occur, and also works very wellto establish dialysis access.
How is the AV graft created?
Creating an AV graft is a surgical procedure, which requires a smallincision at the proposed site. Surgeons sew the graft to an artery andtunnel it, just under the skin, creating a loop back to the startingincision where it is then sewn to a vein. The long loop gives the dialysisnurses space to access the graft. AV grafts can be safely used in about twoweeks, as no maturation of the vessels is necessary. Grafts have a lifespanof approximately 2 to 3 years but can often last longer. However, AV graftscan be more troublesome than AV fistulas. Blood is more likely to clot ingrafts because they are made of prosthetic (foreign) material. When thishappens, interventional procedures can remove the clot and restore bloodflow for dialysis.
Complications related to AV grafts are similar to those with AV fistulas:bleeding, thrombosis (clotting), steal and because of the prosthetic natureof the graft, infection. Infected grafts must be removed immediately and anew access site developed once the infection clears.
What type of dialysis access procedure is necessary for peritonealdialysis?
Surgeons must place a long silicone-based tube called a Tenckhoff catheterinto the abdomen before peritoneal dialysis can begin. The surgeon in theoperating room positions the tube using a local anesthetic and IV sedation.Making a small incision in your abdomen, the surgeon advances the tube deepinto the lower part of your peritoneal cavity (the membrane lining theinside of the abdomen), tunnels the tube under the skin for several inches,brings the tube up through the skin at a different location, and thensurgically closes the initial incision. A sterile dressing covers thecatheter that remains outside of the body.
Tunneling the catheter reduces the likelihood of infection in theperitoneal 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 4weeks after the access surgery.
What types of complications are possible from the Tenckhoff catheter?
Complications related to catheter placement may include bleeding and damageto large or small intestines or abdominal blood vessels. Although unusual,these issues could require additional corrective surgery. Once peritonealdialysis begins, complications related to repeated use of the catheterinclude peritonitis, which is an infection of the peritoneal cavity.Peritonitis, which can be quite serious, is usually associated withabdominal pain, fevers and cloudy peritoneal dialysis solution. If theinfection does not respond to antibiotic treatment, then it may benecessary to remove the catheter.
When should dialysis access surgery take place?
The best approach is to undergo dialysis access surgery well beforedialysis therapy needs to begin, which will give the access site time tomature and avoid the use of temporary catheters. You may need a temporarycatheter while you are waiting for your permanent AV fistula or AV graft toheal.
How does the dialysis access team evaluate individuals for long-termsuccess?
Our team, which includes a nephrologist, interventional radiologist,surgeon and dialysis access coordinator, perform an extensive physical examto identify satisfactory vessels to construct the AV fistula or graft. Wemay request additional studies such as ultrasounds or even dye studies ofthe blood vessels in your arms and legs. After we decide on the appropriatetype of access, we select the location. Typically surgeons constructhemodialysis access in the forearm of your non-dominant hand. If this siteis not suitable then we may choose to use the forearm of the dominant handor the upper arm of your non-dominant hand, above the elbow.
Whom do I call for more information?
For more information about the Transplant Institute at Beth IsraelDeaconess Medical Center, please call 617-632-9700.
