A stent anastomosis comprises a stent segment reconfigurable between a deployment configuration and a shortened, transversely expanded deployed configuration having a transverse dimension larger than its longitudinal dimension. In the deployed configuration, the stent segment engages an inner surface of an intravascular graft, securing the end of the graft within a vessel and forming a seal between the graft and an endoluminal surface of the vessel. The stent segment includes at least one securing member that extends outward from the stent segment in the deployed configuration, that pierces and penetrates the graft, and that pierces the endoluminal surface of the vessel to secure the graft within the vessel. In the deployed configuration, the stent segment can compress the graft against the endoluminal surface of the vessel to form the seal.