What graft flow volume indicates possible congestive heart failure?

• A. 1000 ml/min
• B. 1500 ml/min
• C. 1200 ml/min
• D. 1400 ml/min

Answer: (B)

High graft flow in a dialysis access creates a significant left-to-right shunt, sending more blood back to the heart and increasing preload. When the flow through the graft reaches around 1500 mL/min, the shunt becomes substantial enough that the heart must pump a much larger volume to maintain systemic circulation, which can lead to high-output congestive heart failure. This threshold is used because flows at or above this level are commonly associated with clinically important increases in cardiac workload, whereas lower flows are less likely to provoke CHF. Normal access flows are typically well below this, often in the 600–1200 mL/min range, so 1500 mL/min represents a high-flow state capable of contributing to heart failure.