What is Vascular Access?
Your nephrologist (kidney doctor) may have recently told you that you have advanced kidney disease (also known as end stage renal disease or ESRD) and that you need to begin dialysis. You are not alone. There are currently more than 468,000 U.S. residents who receive dialysis treatment.
Hemodialysis is the process of circulating blood through an artificial kidney to remove waste and excess fluid from the body. In order to receive dialysis treatments, a functioning vascular access is required. A hemodialysis access (vascular access) is a port that allows blood to be passed from the body to the dialysis machine and back to the body during treatment. Without it, the life-preserving treatment of dialysis would not be possible. The term vascular access refers to the fact that it is connected to the vascular system (blood vessels), and it is the means by which blood is accessed (reached).
A vascular access must be created prior to starting regular hemodialysis treatments. There are four basic kinds of vascular accesses for hemodialysis:
- Arteriovenous (AV) fistula
- AV graft
- Central venous catheter (CVC)
- Hemodialysis reliable outflow (HeRO) graft
An AV fistula is a natural type of vascular access in which a person’s own artery is surgically connected to a vein, usually in the arm or leg. This procedure may be performed by a vascular surgeon as an outpatient operation using a local anesthetic. The increased blood flow that results from this connection causes the vein to grow bigger and stronger. The patient is taught to do exercises, such as squeezing a rubber ball, to help the fistula strengthen and mature to get it ready for use.
A fistula requires advance planning because a fistula typically takes two to four months after surgery to develop. Once it has matured, it can provide good blood flow for many years of dialysis. Kidney and dialysis experts consider the fistula the “gold standard” in access choice. Research studies have proven that patients with a fistula have the fewest complications, such as infection or clotting, compared to all other access choices available.
Currently, an access improvement initiative known as “Fistula First” is being sponsored by the Centers for Medicare & Medicaid Services (CMS) throughout the U.S. to support an increase in the use of fistulas in dialysis patients.
The fistula is considered the gold standard access because it:
- Has a lower risk of infections than other access types
- Has a lower risk of forming clots than other access types
- Performs better than other access types
- Allows for greater blood flow
- Lasts longer than the other access types
Not everyone may be able to have a fistula due to weak arteries, veins or other medical conditions.
If you have small veins that will not develop properly into a fistula, you can get a vascular access that uses a synthetic tube implanted under the skin in your arm or leg. The tube becomes an artificial vein that can be used repeatedly for needle placement and blood access during hemodialysis. An AV graft does not need to develop as a fistula does, so it can be used sooner after placement, often within just two or three weeks. Compared to fistulas, grafts tend to have more problems with clotting or infection and need replacement sooner, but a well-cared for graft can last for several years.
If your kidney disease has progressed quickly, you may not have time to get a permanent vascular access before you need to start hemodialysis treatments. You may need to use a central venous catheter as a temporary access. A catheter is a tube inserted into a vein in the neck, chest, or leg near the groin. It has two chambers to allow for two-way flow of blood. Once a catheter is placed, needle insertion for dialysis is not necessary.
Catheters are not ideal for permanent access. They can clog and lead to infection or a narrowing of the veins in which they are placed. If you need to start hemodialysis immediately, a catheter will suffice for several weeks or months while your permanent access develops.
You might be a good candidate for the HeRO graft if you have damaged or blocked central veins and you are catheter dependent for dialysis. Ask your doctor if the HeRO graft is the right option for you. The HeRO graft is a new choice for hemodialysis access designed for patients with an access that is no longer working well because of blockages or damage to the major veins leading to the heart. A failing hemodialysis access is a common problem, especially for patients who have been on dialysis for a number of years. The central veins to the heart can become damaged or blocked over time, causing fistulas and grafts to fail.
Until recently, the only option has been to place a CVC directly into the heart through a large vein in the neck. However, dialysis catheters were never meant to be used long-term and have a number of disadvantages, including high infection rates and limited lifestyle.