What is AV fistula
An AV (arteriovenous) fistula is a surgically made connection between an artery and a vein, typically in the arm, to create a reliable access point for haemodialysis treatment. Over time, the increased blood flow from the artery causes the vein to grow larger and become stronger, making it more suitable for repeated needle insertions during dialysis sessions. For patients with end-stage renal disease (ESRD) who require haemodialysis, the functioning AV fistula is essential for effective treatment.
Why it is done?
Haemodialysis is a medical procedure used to filter and remove waste products and excess fluids from the blood when the kidneys are unable to do so adequately. For haemodialysis, physicians need a vascular access to take blood from the person and allow the haemodialysis machine to clean the blood and then the clean blood is returned to the person. AV fistula is the preferred method of vascular access for haemodialysis because it offers several advantages over other types of access, such as AV grafts or central venous catheters.
How AV fistula is better than any other vascular access?
- It has very low risk of infection.
- It is a long term solution as it does not need to be changed in 3 to 6 month like other central vascular access.
- It is more cost effective than other vascular access, in the long run.
- Unlike a catheter which may be visible in the neck, AV fistula is in the arm or hand and hence not visible with shirt or clothes on and hence more appealing to patients.
- Patients with fistula can take a bath or go swimming unlike those with catheters.
Disadvantages
- Thrombosis
- Stenosis
But these are correctable complications, if picked early and if the AVF fails then a new AV fistula can be made at another site.
Site of AV fistula? How is it selected?
The surgeon does a detailed clinical examination before the procedure and advises ultrasound- doppler of upper limbs to select the best site for AV fistula, it can either be wrist or elbow, preferably on non-dominant hand (the hand you don’t use for eating and writing).
Precautions before and after performing the AV fistula:
- Before the creation of AV fistula, it is advised not to administer any sort of injection on the arm
- The patient should do hand exercises with a small ball (smiley ball) and they should avoid taking BP measurement on the same upper limb
- The patient is called 2 hours prior to the day of surgery and after the procedure, the fistula is checked for its working status on table but it can only be used after six-eight weeks, since the vein takes time for maturation
- During these six weeks there is lot of remodelling which occurs in the vein, the vein gets more thicker and wider.
- As per facts, out of 10 fistulae, only 8 to 9 usually works. There can be several reasons for failure in 10-20% of cases.
- Post operatively we advise the patient not to administer injections on the same upper limb and avoid BP measurements
- The patient is called for follow up 2 days after the surgery and then again after 6 weeks. We perform a USG-doppler to see the blood flow parameters.
Conclusion
- AV Fistula is a daycare surgical procedure, very helpful for ESRD patients needing regular dialysis
- It is a long term vascular access solution and is the first and foremost important step in preparing patients for dialysis
Credits
Image: ncbi.nlm.nih.gov
