A system and method employs collar stents to implant an endoluminal device, such as a stent-graft, in a lumen. The system comprises at least one collar stent adapted to precondition a portion of the lumen for anchoring an endoluminal device having at least a portion adapted to be deployed radially within the collar stent. The method comprises first deploying one or more collar stents, and then deploying the endoluminal device radially within the one or more collar stents. In various embodiments, the collar stent may be radiopaque, may have inwardly protruding barbs for engaging the endoluminal device, and may have a region having a relatively low percentage of open area for bridging a portion of the main lumen having an intersecting lumen. The preconditioning step of implanting the collar stent may change the morphology of the lumen to more favorable morphology, such as from a non-circumferential geometry to a circumferential geometry.
