The role of flow-to-diameter ratio in predicting arteriovenous fistula complications in hemodialysis.

INTRODUCTION

Arteriovenous fistulas (AVFs) are the preferred vascular access for hemodialysis but are prone to complications such as thrombosis, aneurysm, steal syndrome, and high-output heart failure. The Flow-to-Diameter Ratio (FDR), which integrates blood flow and vessel diameter, is a novel hemodynamic metric for AVF surveillance. This study evaluates FDR's association with AVF complications in hemodialysis patients.

METHODS

This retrospective cohort study included 122 patients with radial-cephalic or brachial arteriovenous fistulas (AVFs) who had been on dialysis for ⩾5 years. Data for these patients were collected between January 2022 and January 2024. Doppler ultrasound was used to measure blood flow and vessel diameter to calculate the FDR (mL/min/mm). Patients were categorized into low (<100), normal (100-300), and high (>300) FDR groups. Complications were identified according to the KDOQI guidelines. Multivariate logistic regression and ROC curve analyses were used to assess FDR's predictive value of the FDR.

RESULTS

The mean age was 64.5 ± 11.8 years, and 58% had radial-cephalic AVFs. A high FDR (>300 mL/min/mm) was associated with a 50% complication rate in both AVF types, compared to 17% (radial-cephalic) and 18% (brachial) in the normal FDR group. Low FDR (<100 mL/min/mm) showed moderate complication rates (29% radial-cephalic, 22% brachial). High FDR independently predicted complications (radial-cephalic: OR: 2.38, p = 0.015; brachial: OR: 2.51, p = 0.013). ROC analysis showed AUCs of 0.82 (radial-cephalic) and 0.86 (brachial) at an FDR cutoff of 305 mL/min/mm.

CONCLUSION

The FDR is a robust predictor of AVF complications, with high values indicating an increased risk. Integrating FDR into Doppler surveillance may enhance risk stratification and guide timely intervention.