Dialysis Access Procedures
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At ColumbiaDoctors we offer our dialysis patients state-of-the-art therapy with minimal interruption of your schedule. We provide same-day dialysis scheduling at our midtown or uptown dialysis locations.
What is dialysis?
In a healthy person the two kidneys work together to remove waste, salt, and extra water from the blood, maintain a safe level of chemicals including potassium, sodium, and bicarbonate, and help control blood pressure. When people lose 85 to 90 percent of their kidney function because of chronic or acute health conditions, a procedure called dialysis can take over the work of the kidneys. During dialysis the blood is circulated through a machine that cleans it of impurities and regulates fluid and chemical balances. Many patients with kidney failure undergo dialysis three times a week, sometimes for years.
To prepare for long-term dialysis, surgeons create an easy-to-access portal, called a dialysis access, in the bloodstream under the skin. This portal allows blood to be removed and returned speedily and efficiently during dialysis and is crucial for those who must undergo regular hemodialysis to survive. The most common type of dialysis access is a fistula, in which an artery and vein are joined under the skin, typically in the forearm. If properly maintained, a fistula can last years or even decades. Another, less common type of access is a graft, in which surgeons connect an artery to a vein using a piece of vein taken from the leg, a section of a cow's carotid artery, or a piece of synthetic material.
Both fistulas and grafts can become clogged, narrowed, develop clots, or become infected. When any of these complications occur, you may be unable to undergo dialysis. To remedy these problems ColumbiaDoctors interventional radiologists use image-guided procedures:
A fistulagram is a diagnostic X-ray procedure that enables us to observe the blood flow through the fistula and check for blood clots, narrowing (stenosis), or other blockages. During the procedure we place a tiny tube called a catheter in the fistula, then inject a special dye that can be seen on an X-ray and that highlights the contours of the blood vessels and any blockages. Depending on what we see on the fistulagram we may perform one of the procedures below to correct the problem.
Thrombectomy and Thrombolysis
When a fistula or graft stops working well it’s often because a blood clot (thrombosis) has developed in it. Depending on the composition and location of the clot, interventional radiologists remove it using one of two minimally-invasive or image guided procedures. During a thrombectomy we remove the clot mechanically using a catheter equipped with a specialized tip to break up and remove it. During thrombolysis we use a catheter to deliver a clot-dissolving medication directly to the blockage to break it up. Both procedures are usually completed within one hour.
Some narrowings in a fistula or graft can be opened using an interventional procedure called balloon angioplasty. Using image guidance, we advance an inflatable balloon mounted at the tip of a catheter to the site of the stenosis, then inflate it. As the balloon expands it opens the narrowed vein or artery, and blood flow increases through the fistula or graft. The procedure may be repeated at the same site or at different spots where the vessels have narrowed.
Immediately following balloon angioplasty we may implant a small, flexible wire mesh tube called a stent to keep the fistula or graft open. Using image guidance, we position the stent at the site where we performed angioplasty and expand it open with a balloon, then deflate and remove the balloon.
How do I get ready for the procedure?
On the night before the procedure eat a light meal, then do not eat or drink anything after midnight. We will provide you with more detailed information about which medications you may take in days before and on the morning of the procedure. Plan to have someone drive you home after the procedure.
What will happen during the procedure?
Once you arrive at our interventional radiology suite we will have you lie on a specialized x-ray table. We will give you a sedative intravenously, to help you relax, and will then inject local anesthetic to numb your skin and the tissues around the fistula. We will then insert small catheters into the fistula, then inject a dye into the vessels. If this test reveals a blockage or narrowing, we will work to restore blood flow through the area using one of the procedures above.
Are there any risks?
These procedures are generally very safe. Some patients develop a bruise at the procedure site, which may become very large and uncomfortable, or a temporarily develop a small lump composed of scar tissue as part of the healing process. With angiography and stenting there is a slight risk of bleeding, of the procedure not successfully opening the stenosis, and of a subsequent failure of your fistula/graft. Very rarely, a catheter can damage the fistula/graft, requiring surgery or another radiological procedure.
After the procedure
The length of time it will take for us to complete these procedures varies greatly from patient to patient, as will the time it takes for you to recover, depending on how big and where the blockage is in the fistula. If you are undergoing the procedure as an outpatient, you may go home after a short period or you may spend most of the day in the recovery area. Once at home you may drive after 24 hours, and resume normal activities the next day.