The present invention relates to an apparatus for treating vascular aneurysms, comprising an occlusive support device (100) comprising one or more support members (122) forming a first end portion (124) and a second end portion (126) and defining a lumen (128) therethrough； and an end cap member (132) at said first end portion of said occlusive support device； and, wherein said end cap member has openings and said end cap member comprises a reactive material (133) that is configured to hydrate upon delivery of the device and to reduce the size of said openings.
