An occlusive device suitable for endovascular treatment of an aneurysm in aregion of aparent vessel in a patient, including a structure having a pre-establishedpore features andhaving dimensions suitable for insertion into vasculature of the patient toreach the region ofthe aneurysm in the parent vessel. The device further includes a frangiblematerialassociated with the pore features which initially provides a substantialbarrier to flowthrough the frangible material and is capable of at least one of localizedrupturing andlocalized eroding, in the presence of a pressure differential arising at anostium of aperforator vessel communicating with the parent vessel, within an acute timeperiod tominimize ischemia downstream of the perforator vessel.
