Exploratory Assessment of Muscle Thickness and Stiffness Around Arteriovenous Fistulas Using Shear Wave Elastography

Background/Objectives: Muscle thickness and stiffness near the arteriovenous fistula (AVF) site may influence vascular access function in hemodialysis patients. This exploratory study aimed primarily to describe differences in muscle thickness and stiffness between the AVF-bearing and contralateral limbs, and secondarily to examine whether these parameters were associated with AVF maturation. This study aimed to compare these muscle parameters between the AVF and contralateral sides and to evaluate their relationship with AVF maturation status. Methods: Thirty participants undergoing hemodialysis were included, comprising 22 with mature AVFs and 8 with non-mature AVFs. Ultrasound examinations measured muscle thickness and stiffness using Shear Wave Elastography (SWE) of the biceps brachii and brachioradialis muscles. Volume flow was recorded in the draining vein and feeding artery. Statistical analyses included paired comparisons, group comparisons, Pearson correlations, and multiple linear regression models. Results: Brachioradialis thickness was significantly reduced on the AVF side compared with the contralateral side (p = 0.013, Cohen's d = -0.95), particularly in forearm (radiocephalic) fistulas (Wilcoxon p = 0.014, Cohen's d = -0.95), indicating localized muscle atrophy. No significant side-to-side differences were found for biceps brachii thickness or for stiffness in either muscle (all p > 0.1). Comparisons between mature and non-mature AVF groups showed no significant differences in muscle parameters on the AVF side (all p > 0.4). Conclusions: AVF may lead to asymmetric muscle changes, especially a reduction in brachioradialis thickness, regardless of maturation status, which could affect forearm function. Nevertheless, muscle thickness and stiffness do not appear to predict AVF maturity or vascular access success directly.