RATIONALE & OBJECTIVE: Reducing turbulent blood flow through dialysis arteriovenous fistulas (AVFs) and radial stretching of their venous wall may attenuate hyperplasia and stenosis and improve AVF outcomes in hemodialysis patients. The goal of this study was to evaluate the safety and efficacy of the VasQ implant, which intervenes on these mechanisms by physically supporting the surgical arteriovenous anastomosis. STUDY DESIGN: Prospective, randomized, controlled, multicenter study. SETTINGS & PARTICIPANTS: 40 consecutive patients with kidney failure referred for creation of a brachiocephalic fistula in 4 vascular access centers in the United Kingdom and Israel. INTERVENTIONS: AVF surgical creation with placement of the VasQ implant (treatment) versus AVF placement without the implant (control). OUTCOMES: Safety assessed as percentage of severe device-related adverse events was the primary outcome. Secondary outcomes were efficacy assessments including: (1) AVF maturation at 3 months, defined as cephalic vein diameter≥5mm and flow≥500mL/min; (2) functional cumulative patency, defined as successful 2-needle cannulation for two-thirds or more of all dialysis runs for 1 month in study participants receiving dialysis; (3) cephalic vein diameter and blood flow; and (4) primary and cumulative patency at 6 months. RESULTS: No severe device-related adverse events were observed. There was no significant difference in maturation at 3 months or primary patency at 6 months between treatment and control (85% vs 80% and 80% vs 66%). Significantly larger vein luminal diameters were observed in the treatment group versus controls at 3 and 6 months (8.27±2.2 vs 6.69±1.8mm [P=0.03] and 9.6±2.5 vs 7.56±2.7mm [P=0.03]). Functional patency at 6 months was significantly greater in the treatment group (100% vs 56% [P = 0.01]). LIMITATIONS: Small sample size, limited power for secondary end points. CONCLUSIONS: No safety signals were detected for the VasQ external support of brachiocephalic AVFs. Higher functional patency and vein luminal diameters were achieved with the device at 3 and 6 months. VasQ may safely intervene on mechanisms associated with the disturbed hemodynamic profile in the juxta-anastomotic region. FUNDING: Funded by Laminate Medical Technologies Ltd. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02112669.