Abstract: A stent system is provided comprising a primary stent for location in a lumen of a target vessel, such as a vein or artery that may be fully or partially occluded. The primary stent contacts a vessel wall and at least one secondary stent element is deployed wholly within the primary stent and configured to engage with the interior surface of the primary stent. The secondary stent element is configured to apply a chronic outward radial force to the interior surface of the primary stent so as to effect modification of or to resist change to an aspect ratio of the lumen of the target vessel at the location where the secondary stent element is deployed. In this way the secondary stent element cooperates with the primary stent to restore patency to the target vessel. Various configurations of the stent system are provided as well as deployment devices and methods of treating fully or partially occluded vessels.