Dialysis is a way of cleaning your blood when your kidneys can no longer do the job. It gets rid of your body's wastes, extra salt and water, and helps to control your blood pressure.
There are two types of dialysis; hemodialysis and peritoneal dialysis. In hemodialysis, blood is pumped out of your body to an artificial kidney machine, called a dialyzer, and returned to your body by tubes that connect you to the machine. In peritoneal dialysis, the inside lining of your own belly acts as a natural filter.
Should you choose to have hemodialysis, your dialysis center will need to access your blood vessels. There are two methods for gaining access to the blood vessels; via a catheter or a fistula/graft. A catheter is a soft tube that is placed in a large vein, usually in your neck. An AV fistula is an access made by joining a patient’s own artery and vein directly to each other. An AV graft is an access made by connecting an artery to a vein using a plastic blood vessel.
A catheter is used when a patient needs immediate access for dialysis, typically because the patient has suddenly found out they have kidney failure. A dialysis catheter can be placed by an interventional radiologist or a surgeon. However, using a catheter puts the patient at a much higher risk for infection, since it hangs outside the body. The longer it is in, the higher the risk of infection.
An AV fistula is considered the gold standard for dialysis access. With an AV fistula, blood flows from the artery directly into the vein, increasing the blood pressure and amount of blood flow through the vein. The increased flow and pressure causes the vein to enlarge. The enlarged vein will be capable of delivering the amount of blood flow necessary to provide an adequate hemodialysis treatment. AV fistulas are the preferred vascular access for long-term dialysis because they are made entirely of the patient’s own tissues. There is no plastic or foreign material. They last longer than any other dialysis access types, are less prone to infection and clotting, and can be relied upon for predictable performance.
The issue with fistula dialysis access is not everyone is able to have a successful fistula created due to individual anatomy. Usually this is due to small caliber veins. Also, once a fistula is created, it typically takes between 6 weeks and 4 months to mature. This means, if the patient needs dialysis immediately, they will still need to have a catheter placed while they wait for the fistula to mature to functionality.
If your vascular surgeon determines you are an unsuitable candidate for an AV Fistula creation, he may then evaluate you for an AV Graft Placement. A graft is usually about one-half inch in diameter and made of plastic (Teflon), or transplanted animal or human vessels. They are usually placed in the arm, but can also be placed in the thigh. Grafts become functional much more quickly than fistulas; they can typically be used two to six weeks after placement.
Grafts are created from foreign materials to the body. This makes them more prone to clotting or becoming infected. For these reasons, the graft may have to be replaced yearly. However, they are still a much safer alternative to using a catheter.
When patients find out they are in the advanced stages of chronic kidney disease and will need dialysis, their nephrologist will advise them to be evaluated for a fistula or graft. Having the access in place well before beginning dialysis will give this lifeline time to mature, so it can be ready to use.
When patients suddenly discover they have kidney failure, a catheter may be placed to allow for immediate dialysis treatment. In this case, the patient should still schedule an appointment to see a vascular surgeon. The surgeon will still be able to evaluate the patient for the fistula or graft and then perform the surgery. The catheter will be used until the fistula or graft has had time to mature.
A fistulagram is an X-ray procedure to look at the blood flow and check for blood clots or other blockages in your fistula. If there is a clot, the surgeon will preform an angioplasty or a thrombolysis to break it up or remove it.
Milford Vascular Institute has relationships with many renal specialists throughout the Southern Connecticut area. When a patient suddenly develops kidney failure, MVI has the ability to see the patient within the next business day to both place a catheter and evaluate them for a vascular access. Contact us if you or your loved one may soon require dialysis.