The failing fistula:

All published series concerning percutaneous treatment of thrombosed native fistulas report that an underlying tight stenosis is unmasked in close to 100% of cases, which means that preventive treatment of such stenoses would have avoided acute thrombosis [Cardiovasc Intervent Radiol 25:3-16, 2002].However, we also know that native fistulas are much less prone to thrombosis than prosthetic grafts and that not all stenoses threaten access patency. The challenge is to detect stenoses that will worsen and to tolerate non-threatining stenoses.Flow rate monitoring appears to be one of the best tools to detect active stenoses whose decreased luminal diameter decreases fistula flow proportionally. Some series have already demonstrated a clear reduction in the thrombosis rate of monitored native fistulas. The suggested thresholds are a decrease of 20% at 2 monthly examinations in fistulas with a flow rate below 1L/min [Kidney Int 5:358-362, 2001].

The role of the interventional radiologist in 2003 starts soon after fistula creation. From the 3rd or 4th week after creation surgery, any clinical suspicion of delay in maturation indicating insufficient fistula flow should be imaged rapidly. Non-invasive ultrasound examination should be performed first to rule out the deep location of a well-developed vein which requires surgical transposition to a more superficial location whenever possible.