What duplex features indicate graft stenosis after bypass surgery?

• A. Focal high peak systolic velocity with spectral broadening at the graft anastomosis, dampened distal flow, and abrupt velocity changes across the graft
• B. Uniform low velocity throughout the graft with no spectral broadening
• C. No flow in the graft
• D. Normal, uninterrupted flow pattern

Answer: (A)

Duplex-detected graft stenosis shows a localized, hemodynamically significant narrowing that creates a high-velocity, turbulent jet at the narrowed segment. The focal high peak systolic velocity with spectral broadening at the graft anastomosis indicates acceleration and turbulence caused by the narrowed lumen. Dampened distal flow demonstrates reduced forward flow beyond the stenosis due to the resistance of the narrowed segment. Abrupt velocity changes across the graft reflect a sudden cross-sectional area reduction, a hallmark of focal stenosis. In contrast, absence of flow points to graft occlusion, and uniform low velocity or normal uninterrupted flow suggests no focal narrowing.