Abstract: Objective  To investigate the value of ultrasound gel pad during the ultrasound examination of autologous arteriovenous fistula (AVF) stenosis.  Methods  A total of 31 patients with AVF and venous access stenosis were subjected to ultrasound examination of the blood vessels in the upper extremity. The residual diameter of stenosis was measured using different transaudient medium: ultrasound gel pad and coupant. The repeatability and correlation with brachial artery blood flow were evaluated.   Results  All of the 31 cases had end-to-side anastomosis of radial artery-cephalic vein fistula in wrist. The stenosis located in the venous end of the fistula in 4 cases, and located in the forearm segment of cephalic vein in 27 cases. The residual diameter at the stenosis site was 1.41±0.45 mm measured with couplant, and was 1.89±0.53 mm measured with ultrasound gel pad, the difference was statistically significant (t=-3.806, P<0.001). The inter-observer correlation coefficient (ICC) with couplant was 0.887 (95% CI: 0.761~0.946, P<0.001), and was 0.974 (95% CI: 0.948~0.988,  P<0.001) with ultrasound gel pad.  The brachial artery flow measured by Doppler was 381.29±159.77 ml/min. The residual diameter of stenosis measured with couplant was significantly correlated with brachial artery flow (r=0.765, P<0.001). The measurement with ultrasound gel pad was also significantly correlated with brachial artery flow (r=0.817, P<0.001).   Conclusion  When vascular ultrasonography was performed in patients with AVF and venous access stenosis, ultrasound gel pad can reduce the compression deformities of the veins. Ultrasonography of AVF stenosis using ultrasound gel pad has a better repeatability and a better correlation with brachial artery blood flow than those using couplant.

Key words: Ultrasound gel pad, Ultrasound, Autogenous arteriovenous fistula, Blood flow