Abstract Purpose: To describe 6-month primary outcomes from a prospective, randomized, controlled trial comparing the safety and efficacy outcomes for the Wrapsody cell-impermeable endoprosthesis (endoprosthesis) compared to percutaneous transluminal angioplasty (PTA) for venous stenosis or occlusion in arteriovenous fistulae (AVF). Materials and methods: This prospective, multicentre, international, trial (the WAVE Study, NCT04540302) was conducted across 43 centres in the United States, South America, and the United Kingdom. Patients with AVFs and peripheral venous outflow stenosis/occlusion were randomized (1:1) to treatment with the endoprosthesis or PTA. Results: The primary safety endpoint was the proportion of patients without any localized or systemic safety events through 30 days that affected the access or venous outflow circuit and resulted in a reintervention, hospitalization, or death. The primary efficacy endpoint was the proportion of patients with target lesion primary patency at 6 months, defined as freedom from clinically driven target lesion revascularization or target lesion thrombosis. A key secondary endpoint was access circuit primary patency, defined as the time to loss of primary patency of the access circuit (i.e., the time from the index procedure to any venous outflow circuit re-intervention, access thrombosis, or access abandonment). Conclusion: Results will be ready this spring. Findings from this study are expected to provide insight regarding the clinical utility of a novel endoprosthesis relative to PTA.