Transcatheter embolization of large, high-flow arteriovenous (AV) fistulas carries a significant risk for migration of embolic material through the fistula and into the venous outflow and subsequently into the pulmonary arterial tree. Several strategies have been described to address this risk, including the use of Amplatz "spider" devices, covered stents, and "stop-flow" techniques employing occlusive balloons. This article describes a high-flow renal AV fistula after nephrectomy embolized with use of a constrained Wallstent deployed within the fistula to prevent coil migration. This method allowed for complete occlusion of a large, high-flow fistula by transcatheter embolization with minimal risk of pulmonary embolization.