A Dialysis Access Fistula is a pathology, created surgically for therapeutic reasons. “Malfunction” or “abnormality” of the fistula is therefore a pathology of a pathology. This makes definitions, diagnosis and management of fistula problems complicated. The fistula is created to provide reliable & safe access for dialysis without causing the patient any harm. The points of interest therefore in fistula troubleshooting are: 1. The adequacy & safety of dialysis access; 2. The adequacy of dialysis; 3. The health of the host limb; 4. The effect of the fistula flow on Cardiac Status. In the assessment & management of a fistula, all four need to be addressed. 1. Can the fistula be reliably accessed, with adequate needle spacing? Will adequate hemostasis & healing occur on decannulation? 2. Does the fistula flow (Qa) and outflow (VRP) allow for adequate dialysis? 3. Is there a clinical steal problem? Venous outflow problem compromising the limb? Is the fistula itself a problem – ulceration, aneurysm formation, giant fistula, sepsis? 4. Is the fistula a burden on the heart, in absolute or relative terms? The above questions are answered by: a.) Taking a history of the patient’s dialysis, dialysis access & fistula, b.) Reviewing “Dialysis Numbers” (Qb, Arterial & Venous Pressures), both recent, past & “trends”, c.) Examining the fistula & the host limb, d.) Performing a duplex ultrasound of the fistula circuit using a high frequency probe. Bringing all this information together allows the clinician to determine: - Is there a problem with this fistula? - What is the nature of the problem? - How severe is it? - How urgent is it? - How should it be managed – medical, surgical, endovascular?