What is arteriovenous (AV) fistula?
It is a process where an artery is connected to a superficial vein, so that vein will get engorged over a period of time and can be utilised to draw blood at higher pump speeds during the process of dialysis
How does AV fistula work?
Artery carries purified blood in the body and are situated deep beneath the skin and the blood pressure in the artery is high. Veins carries impure blood in the body and are easily visible beneath the skin. Connecting artery to the vein will increase the pressure in the vein and over a period of time, it will get engorged and thick, so that needles can be inserted to draw blood for dialysis
How is the surgery done?
AV fistula surgery is done usually in the hands, either in the forearm or arm. Usually, non-dominant hand (commonly left hand) is preferred. It is done under local anesthesia usually. It can be done on day-care basis and can be discharged on the same day
Do’s and Don’ts after AV fistula surgery:
- Keep the wound clean till it heals which might take 10 to 14 days.
- Sutures will be removed in 10-14 days and some surgeons prefer absorbable sutures.
- Keep the arm elevated with the support of pillow for initial two to three days till the swelling in the operated hand subsides. Swelling of the hand is commonly seen due to increased pressure in the vein and will subside in 3 to 7 days. If it persists beyond 10 days, it is better to consult the vascular surgeon or nephrologist.
- Start exercising the fistula hand by squeezing the sponge ball, 2 to 3 days after the surgery after the resolution of pain and swelling. It has to be done during free time or at least three times daily for 10 minutes.
- Feel the thrill (vibration) by placing your fingers on the skin over the fistula at least two times a day. If it stops, seek medical help immediately
- Do not take blood pressure on the fistula arm.
- Do not take blood tests from the fistula arm.
- Avoid wearing tight clothing or orna ments on the fistula arm.
- Avoid taking any infusions or injections on the fistula arm.
- Avoid sleeping on your fistula arm. .
- Avoid lifting heavy weights or shopping bags on the fistula hand.
- Avoid applying significant pressure on the fistula hand.
How much time it will take for the AV fistula to mature?
It will take around ‘six’ weeks for the fistula to mature. In some patients, we can use it early and in some, it might take long time to mature. A good fistula should have a diameter of 6mm and length of 6 cms.
What are the complications of AV fistula?
Infection can happen immediately after the surgery or later, but it is very rare.
Infection can happen immediately after the surgery or later, but it is very rare. Thrombosis: Clots can happen in the AV fistula. Commonly happens if the blood pressure drops during or after the hemodialysis. If it happens repeatedly, blood thinners (Asprin or Clopidogrel) are recommended.
Arterial steal phenomenon:
Some patients can experience cold, numbness and pain in the fingers on the fistula hand. This is because of ‘steal’ of blood from the artery to the vein and the blood supply to the distal portion of the hand is compromised.
Bulge in the hands over the course of AV fistula is seen when it is used for many years. It is due to thinning of the walls of the blood vessels. In such cases, site of needle pricks has to be changed. If the bulge is significant, show it to a nephrologist as there is rare chance of bleeding from such sites.
Is the needling of the AV fistula painful?
During initial stages, it might be painful. There are certain creams and ointment, which can be applied 30 – 60 mins prior to dialysis and can reduce pain to a considerable extent. Over a period of time, pain sensitivity will come down and patients will get used to the procedure
What should I do if there is bleeding from the AV fistula site?
There are chances of bleeding from the fistula site after dialysis as the patient would have received heparin. For the same reason, tourniquets are tied on the cannulation site after dialysis which has to be kept for 4 to 6 hours and remove it later. Suppose after removal, if the fistula site bleeds, not to panic, immediately give point compression at that site for 10 to 15 minutes, and if it is severe, visit your dialysis unit.