Intra- and inter-observer agreements of duplex ultrasonography in arteriovenous fistula follow-up

Abstract

Objectives: Duplex ultrasound (DUS) is widely recommended and used as the first line imaging modality in arteriovenous fistula (AVF) dysfunction in hemodialysis patients. However, intra- and inter-observer DUS reproducibility for AVF follow-up has not been thoroughly assessed. This study aimed to evaluate the reproducibility of several DUS parameters commonly employed in clinical settings.

Methods: In this prospective, single-center study, we included patients with AVFs referred to our unit for ultrasound assessment. Two operators independently performed DUS examinations. At the axillary (Ax) and brachial (Brach) artery levels, the following parameters were assessed: blood flow (Q), peak systolic velocity (PSV), resistance index (RI), and Q/RI ratio. In cases of venous stenosis, lumen diameter, PSV, and lesion length were also recorded at the stenosis site. Reproducibility was evaluated using intraclass correlation coefficients (ICCs), coefficients of variation (CVs), and Bland-Altman plots.

Results: From March to May 2025, eighteen patients (61% men, median age 63 [56-74] years) were included. Among the included population, 10 patients had a venous stenosis. For intra-observer agreements, ICCs ranged from 0.88 [0.77-0.95] to 0.99 [0.99-1.00] for both observers. For inter-observer agreements, ICCs were good to excellent for most of the parameters. CVs ranged from 5% to 34%. For Qbrach, Q/RIbrach, CVs were 14 [6-19]% and 12 [8-16]%, respectively. For the quantification of the lumen of the venous stenosis, ICC was 0.92 [0.72-0.98] and the CV was 7 [1-10]%.

Conclusion: This study showed that intra- and inter-observers can be considered as good to excellent for the commonly used DUS parameters for AVF follow-up except for the measurement of the anastomosis diameters.

Keywords: Arteriovenous fistula; Duplex ultrasound; Reproducibility.