Does the direction of arterial needle in AV fistula cannulation affect dialysis adequacy?

The direction of arterial access needles in fistulas and grafts has been a subject of some controversy and there is no study comparing the results either direction of arterial needle placement in cannulation of arteriovenous fistula. We compared mean urea reduction rate (URR) and Kt/V in the same HD patients when dialyzed via antegrade or retrograde arterial needle cannulation.

This was a study involving 22 adults on maintenance hemodialysis for more than 6 months. Doppler US examinations of arteriovenous fistula were performed in all subjects. Pre-dialysis and post-dialysis blood samples were obtained at the patient's midweek HD treatment 4 times a month for each direction. Arterial needle was placed in retrograde direction for the first month. On the second month, the direction of arterial needle was converted to antegrade. Means were compared by paired t-test.

Mean URR and eKt/Vof retrograde cannulation were 74.2+/-7.2% and 1.57+/-0.33. The results were indifferent statistically from those of antegrade cannulation (73.0+/-8.7% and 1.57+/-0.35 (p=0.123)). Mean fistula blood flow was 931 +/- 483 ml/min. No cannulation complication was observed during the study period for both directions.

Both antegrade and retrograde arterial needle placement may be preferred according to center experience without concern of HD adequacy. Longterm outcomes of antegrade and retrograde arterial needle placement such as AVF failure, thrombosis, and stenosis warrant further studies.