An implantable endograft device which may be characterized as an endograft assembly that is effectively anchored with respect to the weakened blood vessel by filling the aneurysmal sac to preclude further enlargement thereof and to anchor the endograft with respect to the aneurysm. In this way, migration of the endograft is inhibited and exposure of the aneurysmal sac to endoleak circulatory pressures is limited thereby minimizing the risk of vessel wall rupture.