An intraluminal device implantable in a blood vessel having an aneurysm therein in the vicinity of a perforating vessel and/or of a bifurcation leading to a branch vessel. The intraluminal device includes a mesh-like tube of bio-compatible material having an expanded condition in which the tube diameter is slightly larger than the diameter of the blood vessel in which it is to be implanted, and the tube length is sufficient to straddle the aneurysm and to be anchored to the blood vessel on the opposite sides of the aneurysm. The mesh-like tube also has a contracted condition wherein it is sufficiently flexible so as to be easily manipulatable through the blood vessel to straddle the aneurysm. In its expanded condition, the mesh-like tube has a porosity index of 55% - 80% such as to reduce the flow of blood through its wall to the aneurysm sufficiently to decrease the possibility of rupture of the aneurysm but not to unduly reduce the blood flow to a perforating or branch vessel to the degree likely to cause significant damage to tissues supplied with blood by such perforating or branch vessel.
