Hemodialysis is the life-saving treatment option for the patients with End Stage Kidney Disease (ESKD). Therefore we need a relatively stable permanent vascular access to keep the hemodialysis going on. AV fistula is the best method of permanent vascular access for long term dialysis. Therefore we need to have good understanding on how to use AV fistula, how to use AV fistula for dialysis and its complications.
What is AV fistula?
Arterio-Venous fistula (AV Fistula) is a vascular connection created between an artery and a vein. This need to be done by a surgeon specialized in blood vessels (Vascular surgeon). Usually your surgeon would select vessels around the left wrist (on non-dominant hand).
Types of AV Fistula
Usually we create AV fistula for dialysis in two major sites.
- Wrist (Radio – Cephalic fistula)
- Elbow pit (Brachio – Cephalic fistula)
Radio – cephalic fistula
Radio cephalic fistula is the most difficult AV fistula to create. This is due to the small size of the radial artery and the cephalic vein around the wrist. Your vascular surgeon will stich the artery and veins to make the AV fistula for dialysis.
As a result of the Radio – Cephalic Fistula, there is a permanent connection between this two vessels. Therefore the high blood pressure of the radial artery cause high blood flow to the cephalic vein. So the cephalic vein get thicker.
Bachio – Cephalic fistula
When we need to create an AV fistula for the chronic dialysis, we often use vessels around the wrist. But as mentioned above it is not an easy surgery. In some patients distal AV fistula get failed. In such situations, we need to try for an AV fistula around the elbow fit.
Your vascular surgeon will connect the basilica artery in the medial side to the cephalic vein in the lateral side at the elbow pit. Then it create a vascular connection between these two arteries.
How to prepare for the AV fistula surgery?
Usually we create AV fistula for dialysis even before 6 months of 1st dialysis. Usually patient is counseled for the method of renal replacement therapy when he turns into the end stage kidney disease.
You will be referred to a specialized vascular surgeon for Av fistula creation.
When you meet your vascular surgeon, he will access some of your general conditions in addition to the vascular issues. This is for the preparation of the surgery.
Then he will perform a vascular mapping to select the best vascular access to create AV fistula for dialysis. As mentioned above, most preferred site of the surgery is the wrist. But if it is not well developed, He will select the Bachio – Cephalic access.
The AV fistula surgery is perform under general anesthesia. But in some stations they are doing it under local anesthesia or nerve block. This is often a day surgery.
After the surgery, your surgeon will review you for the maturation of the Av fistula around 3 months. Until that you need to have some exercise to improve the maturation of the AV fistula.
How to use AV Fistula for dialysis
When we discuss about the haemodialysis, the AV fistula is the most important part of the Haemodialysis procedure. Some says it is the lifeline of the CKD patients.
Assessment of the AV Fistula
The Arterio venous access should be properly maintained during dialysis. You need to continue adequate amount of wrist / arm exercises to improve the quality of AV Fistula.
Usually the vascular surgeon need to access the maturity and usability of the AV fistula for dialysis. If it is not adequately grown, you have to give some adequate exercise before the 1st puncture of the AV fistula site. In addition to the maturity there are some other factors to be assess by the vascular surgeon before allowing the usage of AV fistula for hemodialysis.
Puncturing of AV fistula for dialysis
After the proper assessment, a dialysis nurse or a dialysis technician will do the 1st puncture of your AV fistula for the initiation of the dialysis. The nurse will connect 2 AV fistula needles to your AV fistula site atleast 5 cm away from the surgical site. Usual gauge of the puncture needle for initial dialysis is 17G needles. One needle is inserted to the arterial side of the AV fistula. Then another needle is inserted to the venous side of the fistula.
The arterial needle will be used to drag blood from the body. Then the blood will be going through the dialysis machine. Then venous needle will be used to insert the cleared blood into body.
After the dialysis session, dialysis nurse will remove both needle with adequate pressure to avoid bleeding.
Your dialysis nurse will repeat this procedure in each dialysis session. However when your AV fistula is getting larger, you can select 16G AV fistula needle for the puncturing of AV fistula.
How to pain relive during fistula puncturing?
Each time when you are undergoing haemodialysis, you have to undergo repeated AV fistula site puncturing. Therefore you can use local anesthetic application or spray which include lignocaine like substance.
What are the advantages of AV fistula than other vascular access for dialysis patient?
AV fistula is the most effective vascular access. It has less complication during dialysis. Therefore it is often superior to all other methods like, AV graft, Permanent catheter or temporary catheter.
The benefit of AV fistula is followings;
- Less chance to get clots.
- Less risk of infections.
- No autoimmune mechanisms as it use own vessels.
- Can use as a permanent access as it serves longer than any of other forms.
- Done as outpatient surgery.
- Blood supply is very high.
What are the disadvantages of AV fistula for dialysis?
Even though AV fistula is superior to all other methods, still it has several disadvantages.
- Take some time to mature. Therefore may have to use other temporary methods as vascular accesses.
- This is a difficult surgery. We can’t perform it in some patients with small veins and arteries.
- There are cosmetic issues.
- Maturation need daily regular exercises.
Reference articles
- Lee, C.; Toppin, J.; Snyman, A.; Oreopoulos, G.; Bhola, C.; Djaiani, G. Different anesthetic techniques for arteriovenous fistula formation: Early and late fistula failure rates, European Journal of Anaesthesiology: June 2011 – Volume 28 – Issue – p 121-122
https://journals.lww.com/ejanaesthesiology/fulltext/2011/06001/different_anesthetic_techniques_for_arteriovenous.388.aspx - Increasing the Use of Arteriovenous Fistula in Hemodialysis: Economic Benefits and Economic BarriersDonald Schon, Steven W. Blume, Kimberly Niebauer, Christopher S. Hollenbeak, Gregory de LissovoyCJASN Mar 2007, 2 (2) 268-276.
DOI: 10.2215/CJN.01880606