Sunday, September 13, 2009

When To Refer for AV Fistula Placement

The "Fistula First" initiative, which has as its goal the increase in % of dialysis patients who dialyze via an AV fistula rather than an AV graft or catheter, has been a controversial initiative.  Although few would debate that a working AV fistula is superior in terms of a decreased infection rate and improved graft longevity, there are many patients in whom attempted AV fistulas fail to mature, and delays in waiting for a functional AV fistula to develop have been suggested as a cause of patients who must start dialysis via catheter.  Due to this potential for delay in AV fistula maturation, it makes sense that we should perhaps err on the side of having the AV fistula placed earlier rather than later.  Which brings us to the question:  When should we refer CKD patients for AV fistula placement?

I don't think the answer is clear, but the present KDOQI recommendations are that access placement should occur once the GFR drops to less than 25 mL/min, if the serum creatinine goes greater than 4 mg/dL, or within 1 year of an anticipated need for dialysis.  It also states that a new primary fistula should be allowed to mature for a minimum of 1 month, and ideally for 3-4 months prior to cannulation (AV grafts, by comparison, require a maturation time of only between 3-6 weeks according to these guidelines).  

In this 2004 JASN article entitled, "Late creation of dialysis access for hemodialysis and increased risk of sepis" by Oliver et al, investigators from Canada performed a retrospective analysis of patients starting dialysis who had their access placed either "early" (defined as being placed greater than 4 months before initiating  HD), "just prior" (defined as being placed between 1-4 months before initiating HD), and "late" (defined as being placed 1 month before initiating HD).  Of note, the majority (3687 of 5924) were "late" access placements.  Early access creation was associated with a relative risk of sepsis of 0.57 and a relative risk of mortality of 0.76, both of which were predominantly explained by an increase in catheter use observed in the "late" group.  Granted, this is not a prospective trial, but it does seem to provide some rational evidence in support of early AV fistula placement.  

My personal (and still limited) experience in this area:  I think that many nephrologists know that early AV fistula placement is important, and this is discussed with patients at routine CKD office visits.  The challenges come from two main areas:  (1) actually convincing the patient to go ahead with it (there are often very powerful mechanisms of denial involved in a patient actually accepting the fact that they are eventually headed for dialysis), and (2) administrative delays in setting up a patient to be seen by a vascular surgeon.  If anybody has any tips on ways to increase early AV fistula placement, please share them!

4 comments:

Sandra said...

Fresenius Medical Care offers free pre-ESRD educational classes to people with CKD. One of the topics disussed is vascular access. Early AVF placement is stressed to all that will be choosing HD as their RRT. After hearing about the cons of CVC's, patients are more willing to have an AVF placed when the nephrologist reccomends to do so. This class has been very beneficial to all the patients that have attended, and I have seen a dramatic increase in the number of patients starting HD with a functioning native AVF. The key is to start the education proccess once the patient reaches Stage 4. As stated earlier, the classes are FREE and anyone can attend. You can call 1-866-647-9396to schedule a class for a patient or get more information.

Michelle said...

The day I had my fistula created was the most psychologically traumatic day of my life. When you refer to "powerful mechanisms" being in play, that's a vast understatement. It's not even so much denial, rather it is recognition that this is the first step into the deep, dark void that is dialyis. It is excrutiatingly difficult to willingly take that step because you know that when you awaken from surgery, life as you've known it will be gone forever. So, keep that in mind when you first begin speaking to your patients about getting an access placed.

Matt Sparks said...

@Michelle- Thanks for your comments, we appreciate them.

F.A.C.E. of Lupus said...

I have been informed that I will need to have this procedure. After being at Stage 4 Kidney Failure for almost 15 years, it has finally come to this. I still am not accepting/believing that I will ever use this fistula for diaylsis, I did have a hard time proceeding with the appointment. I prayed about it and asked God to give me peace if this was something that I was supposed to do and he has. I have peace and I am standing on his word that I am healed. Believe God for your healing and keep living your life.