Rethinking surveillance of arteriovenous access: The unmet potential of Doppler ultrasound and the emerging role of multiparametric ultrasound

Arteriovenous fistula (AVF) thrombosis remains the leading cause of vascular access failure in hemodialysis. Surveillance programs aim to detect significant stenosis before thrombosis occurs; however, preventive strategies have shown inconsistent outcomes. Both clinical examination and Doppler ultrasound (DUS) are operator-dependent, contributing to variability in surveillance effectiveness. We propose a physiology-based AVF surveillance strategy centered on DUS, integrating anatomical assessment with quantitative Doppler parameters. The approach combines residual diameter, peak systolic velocity (PSV) ratio, and access blood flow (Qa) to characterize stenosis severity and hemodynamic relevance. The complementary and emerging role of multiparametric ultrasound (mpUS) techniques is also described. Clinical examination provides early bedside information, while DUS enables simultaneous evaluation of vascular anatomy, flow velocities, and Qa in a single non-invasive assessment. Instrumental surveillance methods based on dilution or pressure monitoring increase objectivity but have not consistently improved long-term access patency. Variability in DUS acquisition and interpretation currently limits its clinical impact. A combined diagnostic model based on residual diameter, PSV ratio, and Qa allows differentiation between geometric (Venturi-effect) and hemodynamically significant stenosis, supporting appropriate timing of intervention. Emerging mpUS techniques, including shear-wave elastography and vector flow imaging, may further enhance early risk stratification by assessing vessel wall mechanics and flow shear patterns. The key issue in vascular access surveillance is not whether to monitor, but how to monitor effectively. A standardized, physiology-driven DUS strategy has the potential to shift AVF surveillance from reactive intervention to proactive management. When performed consistently by trained operators, DUS represents not a complement to clinical monitoring, but its natural extension.