***SVU-CME version (for Sonographers/Technologists)***
First published January 17, 2021
Percutaneous endovascular arteriovenous fistula (Endo-AVF) is a minimally invasive alternative to conventional surgical dialysis access. Endo-AVF may represent a significant advance in the creation of dialysis access but may require a variety of additional procedures to achieve adequate flow. To maximize flow through the cephalic vein, usually the preferred vessel, it may be necessary to permanently occlude competing outflow branches such as the brachial or basilic vein. Ultrasound monitoring of cephalic vein flow in the vascular lab can be used to predict the efficacy of basilic vein ligation but requires 2 operators to perform. We developed a simple technique to temporarily obstruct basilic vein outflow using a standard dialysis clamp that can be performed by a single vascular technologist. With the patient in the supine position, the spring-loaded dialysis clamp is positioned over the basilic vein in the upper arm using ultrasound guidance. The clamp applies mild, painless obstruction of the basilic vein without interfering with arterial inflow or cephalic vein outflow. Cephalic vein peak systolic velocity, intraluminal diameter, and flow volume are recorded. This technique was used in 6 patients, 4 to 6 weeks, following the initial Endo-AVF procedure. Ultrasound surveillance confirmed that the basilic vein outflow was effectively occluded in all 6 cases. The same ultrasound machine was used in all 6 studies. Cephalic vein flow increased significantly in each case (pre-clamp cephalic flow volume 301 ± 66.8 mL/min vs post-clamp 702 ± 156.5 mL/min after, P = 1.0). Ultrasound observation of the basilic vein post-clamp application concluded there were no complications related to the use of the dialysis clamp. The average duration of the procedure was less than 20 minutes. We have successfully developed a simple non-invasive technique to predict the effect of basilic vein occlusion on cephalic vein flow that can be accomplished by a sole vascular technologist. This technique can be used to guide the need for embolization of the basilic vein.