Rule of 6s: Sonographic criteria for AVF maturation.
CRITERIA | DESCRIPTION |
---|---|
Outflow vein calibre ≥6 mm on ultrasound | Outflow veins will progressively dilate over time. Generally, a calibre of 6 mm is indicative of an outflow vein that is easy to cannulate and will provide sufficient flow for hemodialysis |
Outflow vein depth <6 mm on ultrasound | If outflow veins are too deep within the subcutaneous tissues, they may be difficult to cannulate. Those that are too deep may require further surgery for superficialization |
Blood flow >600 mL/min | Sufficient blood flow is required through the outflow vein to support adequate hemodialysis |
Cannulation >6 wk postcreation | It is often best to wait at least 6 wk postcreation before cannulating an AVF to allow it to arterialize appropriately. This can minimize cannulation-related complications such as hemorrhage or false aneurysms |
AVF—arteriovenous fistula.