What Is Dialysis?
Filtering about 180 liters of liquid a day, kidneys serve to regulate the balance of electrolytes in the blood. When these extremely important organs fail to work at full capacity, usually starting at 10-15% of normal function, patients must begin dialysis.
Hemodialysis is the use of a machine, sometimes referred to as an artificial kidney, to clear the blood of waste and excess water from the blood as a replacement for normal kidney function. Because kidneys have such an important role in maintaining good health, dialysis must be performed regularly. The frequency and length of each dialysis treatment depend on the health of the patient's kidneys, the size of the patient, the amount of fluid retained after the previous session, and the type of artificial kidney used.
Dialysis is a major time commitment, often taking three to five hours per session and is uncomfortable for the patient. Because of its function, an artificial kidney requires entrance into the blood vessels to access the blood and chemicals it needs to filter. A physician creates an entrance into the blood vessel through minor surgery on the arm or leg.
What Is an AV Fistula for Permanent Dialysis Access?
Dialysis is performed so regularly for some patients, that it makes sense to create a permanent access point for dialysis. This often comes in the form of a fistula, or the joining of an artery and a vein in the arm, that provides a steady flow of blood that can be filtered and processed by the artificial kidney. Arteriovenous fistulas are considered the gold standard for patients who require dialysis on a regular basis.
AV fistula offer a number of advantages over the two more traditional methods of accessing blood during dialysis.
Catheters are usually used for short-term access, but can sometimes be permanent. A catheter is inserted into a large vein or artery in the neck or chest for access to the blood. Catheters are considered a poor permanent option for dialysis because they sit both sides and outside the body and are prone to infection. The catheter must also always be kept dry, so swimming or bathing are not allowed. They are also unsightly and unwieldy when getting dressed and undressed. Of the three options, catheters allow for the slowest flow of blood.
An AV graft is one superior alternative for a catheter. An arteriovenous graft is created similarly to a fistula, connecting a vein to an artery, but it employs a plastic tube that is healed over by its surrounding tissue. Hemodialysis can be performed by inserting two needles on either side of the tube--arterial and venous. The graft greatly increases the rate of blood flow during dialysis, shortening the time required to perform it. An AV graft requires the patient to take good care of the access point, as it might be prone to complications otherwise.
The third option is the arteriovenous fistula, deemed the best option by most doctors. Rather than using a plastic tube, a fistula is created by connecting an artery directly to a vein. Once it has matured and grown, a fistula is a natural part of the body and requires less attention and care than an AV graft. A mature fistula that has grown bigger and stronger can provide good blood flow for decades. Because it is a natural part of the body, patients can "exercise" the fistula and make it grow through exercises like squeezing a rubber ball.
Why are AV Fistula Considered the Best Option for People with Kidney Disease?
The AV fistula is preferred over grafts or catheters by most doctors for a number of reasons. It tends to offer the greatest amount of blood flow, so patients are in dialysis and uncomfortable for the shortest amount of time. Because they are a natural part of the body, they last much longer and are less expensive to maintain than a graft or catheter. They also offer a much lower risk of infection or clotting, which means fewer complications for patients who are already dealing with regular dialysis.
Some doctors believe that those who already have an AV graft or a catheter implanted might still be good candidates for an AV fistula and should be reevaluated. A strong initiative has begun to persuade physicians and patients alike to choose an arteriovenous fistula.
What are the Risks for an Arteriovenous Fistula?
There are few risks for an AV fistula, but it might result in infection, clotting of the vessels, narrowing of the blood vessels in the fistula, or an aneurysm due to the weakening of those blood vessels. Bleeding might occur in some patients.
A major complication may be that the fistula takes too long to heal or never heals properly at all.
Furthermore, not every person suffering from kidney disease is a good candidate for an AV fistula. Patients with highly compromised vascular systems may not have the ability to heal a fistula and are therefore unsuitable for an AV fistula.
Some patients prefer not to get AV fistula for cosmetic reasons, as they result in an unsightly bulge in the arm.
How Do I Take Care of an AV Fistula?
To take care of an AV fistula, patients need primarily to ensure unrestricted blood flow to the fistula by avoiding tight clothing or jewelry. Pressure on the area from carrying heavy objects or blood pressure measurement can also impede blood flow.
Patients with AV fistula should never allow blood to be drawn from anywhere except the access point.
