A stent graft (34) extends in a flow lumen (10) to span a defective portion (18) of the flow lumen (10) and seal the defective portion from further blood contact. The stent graft (34) includes a pair of apertures, from which extensions (50, 52) project into the renal arteries (24, 26) to seal the passage of blood into the renal arteries from the abnormality. The apertures are larger than the opening of the renal arteries, such that the apertures need not be centered with the renal arteries to enable placement of the extensions.
