In duplex assessment of dialysis fistulas, which abnormality would be considered normal?

In the context of duplex assessment of dialysis fistulas, high flow rates greater than 300 ml/min are indeed considered normal. This is because hemodialysis fistulas are created specifically to provide a vessel that can handle high blood flow for effective dialysis treatment. A functioning fistula is expected to demonstrate increased flow rates to ensure adequate dialysis sessions, and measurements above 300 ml/min indicate that the fistula is functioning as intended.

Presence of collateral veins and low resistance flow can indicate potential issues or complications with the fistula, such as stenosis or thrombosis, rather than normal function. Moreover, while normal diastolic flow is a important aspect of vascular assessment, it would not stand alone as an indicator of normality without considering other factors such as flow rates. Thus, the presence of high flow rates above 300 ml/min is what signifies that the dialysis fistula is performing well and is characteristic of a healthy, functioning fistula.