Placement of Hemodialysis Catheters
| When kidneys fail, function of the kidneys can be partially replaced using a process called hemodialysis. Hemodialysis involves drawing blood out of the body, filtering it through a large machine that draws off the impurities and then returning the filtered blood to the body. When patients are placed on hemodialysis, they will require placement of a plastic tube into a large vein at the base of the neck. This plastic tube is called a hemodialysis catheter. It is connected to a hemodialysis machine and is a vital connection between the patient and the hemodialysis unit.
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| Patients in need of hemodialysis access may be sent by their kidney doctor to the Interventional Radiology Division. Here, specialty trained doctors use advanced technology equipment to place a hemodialysis catheter. A combination of machines including a ultrasound machine and a fluoroscope are used to safely access the large vein at the base of the neck and slide a plastic tube into the venous system. Once in place, this catheter is securely fixed to the skin and can remain with the patient for weeks to months. This catheter will need special care and is explained to the patient at the time of catheter placement.
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Once the catheter is in place, for most patients, reliable hemodialysis can be obtained for weeks to months. Occasionally blood clots will form around the catheter in the vein. These blood clots can cause catheter malfunction. Additional procedures performed in the Interventional Radiology Division can unplug these catheters and allow them to work for longer periods of time. Hemodialysis catheters can also become infected. Infections spreading from the skin down along the |
| catheter or infection elsewhere in the body spreading through the veins to the tip of the catheter may mean the catheter needs to be removed.
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| Hemodialysis Fistulas |
| Although hemodialysis catheters placed in the large veins of the neck can give effective dialysis, in the long-run most patients are evaluated for placement of a more permanent method of hemodialysis. This usually involves creating a connection between an artery and a vein somewhere in the arm. Sometimes, a small arm artery is connected directly to a vein just underneath the skin. Over time this vein becomes very dilated and has rapid flow in it. Once this occurs, two small needles can be placed into this vein and they can be connected to a hemodialysis machine.
Some patients have few satisfactory veins. In this case, a plastic tube can be tunneled just underneath the skin. The ends of this tube are surgically connected to an artery and a vein somewhere in the arm. High flow within the plastic tube (called a graft) allows the hemodialysis machine to draw blood off and filter it rapidly.
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| Interventional Radiologists Role in Managing Hemodialysis Grafts |
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Hemodialysis fistulas and hemodialysis grafts are created in the operating room by a vascular surgeon. These fistulas and grafts can be expected to last months to years. This reliable hemodialysis access will be used as long as there is good flow. Over time, the veins in the arms will narrow down due to the high pressure and rapid flow caused by the unnatural connection between an artery and a vein. When this narrowing occurs, flow in the fistula or graft may slow down or even stop. Fortunately there are surgical techniques and interventional radiologic techniques for reopening these fistulas. |
| Fistulography
Patients with slow flow in their dialysis fistula are often sent to Angiography and Interventional Radiology for a study called a fistulogram. A needle is placed in the fistula just like at dialysis. An x-ray contrast is squirted into the fistula and an x-ray image is taken. These often reveal an abnormality in the vein. A second puncture is made and a small plastic tube with a balloon on the end is advanced. This specialized device is called an angioplasty balloon catheter. It is used to balloon dilate the area of abnormality. By stretching open the vein with a balloon, flow will be improved and normal hemodialysis can be resumed.
Occasionally flow in the graft is so slow that clot forms. In the interventional radiology procedure room, we can also use a variety of techniques to remove this clot. This procedure is known as a thrombectomy. In reality, the clot within the graft or vein is either dissolved with medicines or broken up into small pieces using a specialized device. Once the clot is gone, a fistulogram can be performed and an underlying abnormality treated. Fistulography and fistulography with thrombectomy are usually out-patient procedures. Patients are usually discharged either to home or sent back for hemodialysis. |
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