Post-stenotic arterio-venous fistula vein wall flutter as a potential ultrasound sign of significant stenosis - three case reports

Native arteriovenous fistula (AVF) remains the gold standard for hemodialysis vascular access, but stenosis is the principal cause of access dysfunction and failure. Duplex ultrasound (DUS) criteria for significant stenosis are relatively complex and may not always reliably identify lesions at increased risk of progression. There is therefore a need for simple and easily recognizable ultrasound signs for hemodynamically relevant stenosis. We report three cases of failing radiocephalic AVFs in which a visually apparent, low-frequency, high-amplitude fistula vein wall flutter was detected on DUS immediately adjacent to the site of perianastomotic stenosis. In the first case, wall flutter was observed while access flow was still preserved and preceded subsequent flow decline. In the second case, wall flutter prompted surgical reanastomosis; the finding recurred due to venous kinking, and the AVF remains under close ultrasound surveillance. In the third case, wall flutter resolved following balloon angioplasty although access flow remained borderline, indicating a relevant improvement in local hemodynamics. Low-frequency, high-amplitude vessel wall flutter is a recurrent and visually apparent ultrasound finding, which seems to be associated with a hemodynamically relevant AVF stenosis. A significant stenosis can cause a post-stenotic pressure drop that may result in negative transmural pressure, leading to transient wall collapse and resulting flutter. As a dynamic and easily recognizable sign, vessel wall flutter may serve as a useful adjunctive ultrasound finding potentially associated with clinically significant AVF stenosis. Prospective studies are warranted to validate its diagnostic and prognostic value.