Intravascular devices (e.g., stents, stent grafts, covered stents, aneurysm coils, embolic agents and drug delivery catheters and balloons) are used in combination with fibrosing agents in order to induce fibrosis that may otherwise not occur when the implant is placed within an animal or to promote fibrosis betweent the devices and the host tissues. Compositions and methods are described for use in the treatment of aneurysms and unstable arterial (vulnerable) plaque.