Arteriovenous access is required for haemodialysis in renal failure patients. The upper limb is generally preferred as a site, however, lower limb access can also be obtained. Ultrasound is the preferred modality for evaluation of the vessels prior to creating an access.
Types
- arteriovenous fistula (AVF): most common
- arteriovenous graft
- venous catheter
Arteriovenous fistula
A direct communication is created between an artery and vein. In due course of time, the caliber of the vein will increase and the wall will become thicker thus making it easier to puncture for hemodialysis. This is the most common method of approach.
Arteriovenous graft
This involves creating a communication between an artery and vein via a synthetic graft. The graft is placed subcutaneously and can be punctured at the time of hemodialysis. In cases of arteriovenous fistula failure a graft can be placed.
Venous graft
This involves placing a catheter (e.g. Vascath) in direct communication with one of the central veins. Generally used this is a last resort when the fistula and the graft have failed.