Dialysis Access: Fistula or Graft? How to figure it out

First of all, what’s the difference between a fistula and a graft?

To do dialysis you need to be able to consistently insert two large bore needles, 3 times a week.  This is typically done via a fistula or graft.

Fistula: An artery is redirected to directly connect to a vein.  Over time the arterial pressure causes the vein to get super big.  This super big vein segment is the fistula.

Graft:  A synthetic tube is placed which connects an artery to a vein.  This synthetic tube is the graft.

Why do you need to know the difference?  There are a few reasons, but an important one is infection.  If a graft is infected that is a foreign body and needs to be removed.  Fistulas are not foreign bodies and are not removed.

So, How do I tell the difference?

1. Location
2. Surgical Incision
3. How it feels

Location

The access is either going to be in the forearm, the upper arm, or the thigh.

Forearm

• Radiocephalic Fistula: (Radial artery to cephalic vein) – If it starts at the wrist, below the base of the thumb, it’s a fistula.
• Loop Graft: (Brachial artery to cephalic or brachial vein): If it’s a horseshoe shape on the supine part of the forearm, it’s a loop graft.  (Don’t see loop grafts too often).

Upper arm

Upper arm:  Can be fistula or graft. Need to go on to steps 2 and 3 to differentiate

• Brachiocephalic fistula: (Brachial artery to cephalic vein).
• Brachiobasilic fistula / Basilic vein transposition: (Brachial artery to basilic vein, which is deep and needs to be superficialized).
• Graft: (Brachial artery to axillary vein).

Thigh

Thigh:  These are not common and are usually (but not universally) grafts.

• Graft: (Superficial femoral artery to common femoral vein).

Surgical Incision

• Fistulas usually have one incision, where the artery and vein are connected. In the wrist and basilic – cephalic fistula, it’s a small incision.  For the basilic vein transposition it’s a long incision (required to transpose or superficialize the basilic vein) extending up and down the upper arm.
• Grafts usually have two incisions. One at the arterial anastomosis and the other at the venous anastomosis.

Feel

• A fistula is a vein so it’s going to feel like a vein; that is spongy.
• A graft is a synthetic tube so it’s going to feel like a synthetic tube, firmer and formed.