The invention regards an aneurysm device endovascularly deliverable to a site proximate an aneurysm near a terminus of a parent artery with bifurcating downstream arteries, the aneurysm device comprising: a closure structure comprising a distal-facing aspect configured to at least partially occlude the aneurysm and a proximal-facing aspect configured to arch over lumina of the downstream arteries, wherein the closure structure comprises a perimeter support including a plurality of struts and an inner support including a plurality of struts, and a supplemental stabilizer connected to the closure structure, the supplemental stabilizer configured to reside in the parent artery and press outward against a luminal wall thereof, the supplemental stabilizer has a proximal framework portion, and the lateral axis of the distal framework portion comprises a vertex from which the proximal support framework is biased to press outward against a luminal wall of the parent artery.