When a patient presents for evaluation of the access at an affiliated American Endovascular center, a complete history and physical exam is performed of the patient’s access. Other questions are asked about the patient’s overall health. Once determined that the procedure can be performed safely as an outpatient, the patient is brought into the operating room. The arm is cleaned in a sterile fashion and the skin is anesthetized with Lidocaine. Lidocaine can cause a pinch and burn for a couple of seconds, but that then numbs the skin to allow for the angiocath, a small IV, to be introduced into the access.
Pictures are then taken using fluoroscopy, which is a live X-ray. We inject contrast dye into the access, which flows with the blood. It will show the areas of narrowing, tortuosity, and sometimes thrombus if it’s present. Once the decision has been made to perform angioplasty or stent placement for that patient, they will be given medication. The medications we typically use are Fentanyl and Versed. Fentanyl is a narcotic which helps with pain, and Versed is a benzodiazepine, which helps to relax the patient.
The patient will not be fully sedated because the procedure can be performed relatively quickly. We would like to have the patient retain complete control over their breathing and which also ensures that the blood pressure does not drop. Typical procedures for maintenance, such as those requiring angioplasty or stent placement, can take approximately 15-30 minutes. More complicated procedures, such as a thrombectomy or a maturation of a fistula or a graft, may take a little longer – perhaps 30 minutes to one hour. After the procedure, the patient will be brought to the post-operative area, where they will be monitored for complications and to ensure that they are able to get up and walk out of the office on their own.
Why is it Important for Patient to Have a Fistula or Graft for Dialysis Access?
In the past, the research regarding dialysis access has looked at what is more beneficial for a patient – to have a fistula or a graft, or a hemodialysis tunneled catheter. Historically, the belief was that those patients with dialysis catheters do a lot worse. If you take all patients starting with dialysis and you divide them up into those patients with a fistula or a graft, or a catheter on the other side, patients with catheters may experience increased infections and increased central venous stenosis resulting in swelling and other difficulties.
The opinion throughout the years was that this was all related to the dialysis catheter itself. With a catheter, there is an increased risk of infection because it is a foreign object that is introduced into the internal jugular vein, with the tip of the catheter being at the entrance of the heart. The other side of the catheter exits through the skin and has an entrance that allows for bacteria from the skin or the outside world to enter into the central circulation.
Over time, it has been established that not everybody requires a fistula or graft, and there is a subset of patients that can benefit sufficiently from a catheter. For these patients, the potential negative outcomes are outweighed by the less invasive treatment.
Those patients that can benefit have been looked into with many other studies. The point is that there are some patients, for example, those with comorbidities or who have a decreased ejection fraction so their heart is not strong enough to support a fistula or a graft, who may benefit from a tunneled hemodialysis catheter. However, these patients are few and far between. For the most part, those patients starting dialysis should start with a fistula or a graft.
In the video above, I draw a simplified picture of the fistula in order to explain what is actually going on inside the arm. This will also allow me to explain the complications and how we treat them. If we start from the heart and blood flowing out of the heart down the arteries towards the arm and the hand, the surgeon will create a connection between the arterial tree and the venous tree. The blood comes down the artery, down the arm towards the hand, but also, because of this new connection, the blood flows through the vein. This part is the fistula. This is where the needle will be placed for dialysis.
The word fistula means connection. However, in the dialysis world, the fistula is the area where the needle will be cannulated into the vein. If the patient does not have a good vein that is suitable for this connection, the surgeon will use a graft which is made of expanded polytetrafluoroethylene (ePTFE). This is connected through the artery into a larger vein higher up in the arm. The area that will be cannulated for dialysis will be the graft area.
The idea behind a fistula or a graft is that the body protects the fistula or the graft from infection, and from other problems, by using the barrier of the skin for protection.
The catheter exposes the circulation to potential infection from bacteria either on the skin, or from the outside world. Therefore, between the quality of life and decreasing risk of infection, the fistula or graft is an overall better option than the hemodialysis tunneled catheter.
Can Angioplasty Help with Dialysis Access Management?
When you have narrowing of the vein, and sometimes of the artery, the flow will be disturbed. Either you won’t have enough blood flow coming in or you won’t have the ability to have all the blood flow go back out towards the heart. To remedy this situation, we could use angioplasty. Angioplasty is a small balloon that we insert past the area of narrowing. The balloon will then be inflated. After the balloon is inflated for approximately five seconds, we deflate the balloon, remove it, and take a picture to ensure that the vein is back to its original size.
The narrowing that occurs in the venous part of the fistula is usually intimal hyperplasia, which is scar tissue building up. The creation of the fistula is very unnatural. We are asking the body to have your veins act as arteries because now we have arterial flow going through the veins. The veins get irritated and try to scar down to protect themselves. We want the veins to be wide open to allow the blood flow to get past. It is a battle between us and your veins to keep the veins open and allow for adequate blood flow so that your blood can get clean at dialysis.
Angioplasty can, and usually is enough to, improve the blood flow past this area. Just because we do it once doesn’t mean that you will never need angioplasty again. In fact, scar tissue can very frequently return. For every patient it will be a different amount of time; some patients it will take three months, some six months, and some are lucky enough that the scar tissue doesn’t return at all. The angioplasty balloon that we use to open up and expand the areas of stenosis, areas of narrowing, very often will be successful.
However, in the cases that there is an area of elastic recoil lesion, where the force keeps pushing back into the vein, causing the vein to be narrow, we have to place what’s called a stent. A stent is like a spring, almost like on the inside of a ballpoint pen. It is a curved spring made of nitinol that we are able to deploy at the area of narrowing. If the forces are pushing against the vein and making the vein smaller, the stent can actually give structure to the vein and push those forces back. This allows for adequate flow back to the heart.
What Happens When Your Access Becomes Dysfunctional?
After the fistula or graft is up and running, it will, in most cases, require maintenance. The scar tissue or narrowing that caused many of the difficulties, to begin with, doesn’t just go away after one angioplasty or a stent. Sometimes the narrowing will return. The unnatural state is there 24/7. Every time the heartbeats, it’s running through the vein or the graft, which is not how nature intended.
The scar tissue can build up, sometimes between three and six months, causing difficulties at dialysis. Some of the difficulties can lead to high-pressure complications. Some complications can arise with cannulation when you’re trying to stick an access to the fistula or graft. Other complications can include prolonged bleeding when they remove the needle from the access.
If there is high pressure, the blood will come out of that hole from the dialysis needle. We have to make sure that there is decreased pressure and avoid this bleeding complication. Other difficulties and pain for the patient can come from this high pressure causing poor healing or ulceration at the cannulation site. Some of the more central narrowing can cause swelling and cramping for the patient. If the narrowing within the arterial inflow or the venous outflow is severe, there may not be enough flow through the fistula or graft, and the graft can clot. The patient would be referred for a thrombectomy, which is a procedure to remove the clot and to repair the cause of the thrombosis.
Another complication can be something called steal syndrome, where the access is stealing blood away from the hand. If there is too much flow coming into the access, there is not enough flow going down to the hand.
This would cause numbness, stiffness, and cramping for the patient. In order to remedy that problem, we would actually make the inflow a little smaller. So just after the connection between the artery and the vein or the artery and the graft, we would make that area a little smaller, decreasing the amount of flow into the access and improving blood flow down to the hand. When there is steal syndrome, the patient would benefit from a banding procedure where we would decrease the amount of flow into the access and improve flow down to the hand, improving their symptoms. These are just some of the dialysis access procedures that are performed here at American Endovascular.
How Should I Care for My Access?
Proper care for the access starts with cleanliness. Washing the arm daily with soap and water is enough. You do not need harsh abrasives to make sure that you remove all of the bacteria from your skin. On dialysis days, we usually ask the patients to remove the dressings that are applied at an affiliated American Endovascular center a few hours after they get home. Removing the dialysis pressure dressings allows the skin to breathe and be cleaned properly. If there is still some bleeding when removing the dialysis, slight pressure on the access and on the areas that are bleeding with one finger should be enough to stop the bleeding. A small band-aid can then be placed afterwards. If there is excessive bleeding, that’s the first clue that there are difficulties at dialysis.
When patients present to us at an affiliated American Endovascular center, we go through the exam with them. We want our patients to realize what a normally functioning fistula should feel like, so that when there is dysfunction, they realize immediately that there is a problem. The patient is the first line of defense against fistula dysfunction. If there are difficulties, we recommend our patients to call immediately and make sure that we investigate what could be a problem at dialysis and within the access.