Ideally, you should have permanent access placed for hemodialysis far enough in advance of your first hemodialysis treatment so that you never have to be dialyzed through a central venous catheter. That’s easier said than done, since it is nearly impossible to predict exactly when your first hemodialysis treatment will occur. So there are a couple of ways to go about this. One would be for your nephrologist to estimate when you might need dialysis based on the rate of decline in your kidney function, then to refer you for vascular access evaluation about 6 months before that time. That will give the surgeon time to do the appropriate evaluation of your vessels, perform the vascular access surgery, and give you sufficient time for the access to mature. Another approach is the “30-20-10” rule that recommends that you be referred to a nephrologist when your glomerular filtration rate (GFR) is no less than 30 mL/min, that you be referred to a surgeon when your GFR is about 20 mL/min, and that you be considered for dialysis when your GFR is around 10 mL/min. These are ballpark figures and not hard-and-fast rules.
An arteriovenous fistula (AVF) is the best vascular access for most patients, but it takes the longest to mature (2-6 months) and may require several procedures before it is fully functional. However, the longer it has had to mature, the better it works when it is needed for hemodialysis. An arteriovenous graft (AVG) is generally not a durable as an AVF, but takes only 3 or so weeks to be usable once it’s put in. An AVG should not be put in too far in advance of the need for dialysis because it may narrow down with age. The surgeon will decide if you’re a better candidate for an AVF or an AVG. If it’s an AVF, the more in advance of the need for dialysis it’s put in, the better. If it’s an AVG, the surgeon will probably recommend waiting until you’re getting close to needing dialysis (about a month or so in advance).
Jay Wish, MD