The present application discloses an apparatus for treating vascular aneurysms and includes an occlusive support device comprised of one or more support members. The occlusive device has a first end portion and a second end portion, an end cap member at the first end portion of the occlusive support device, and an anchoring member at the second end portion. The end cap member is comprised of at least one of one or more of the support members. The end cap member has openings and the end cap member comprises a reactive material that is configured to hydrate upon delivery of the device and to reduce the size of said openings. The end cap member has an end cap diameter and the end cap is generally perpendicular to the longitudinal axis of the support device. The end cap has an extension along the longitudinal axis of said device that is less than two times the end cap diameter. The device is configured so that the occlusive members can be positioned in the blood vessel proximate the neck of a vascular aneurysm, the reactive material hydrates and increases the resistance to blood flow into the aneurysm, and the anchoring member anchors the device in the blood vessel without occluding flow through the blood vessel.
