A primary stent-graft is deployed into a primary vessel to exclude an aneurysm. To maintain perfusion to a branch vessel covered by the primary stent-graft, a gutter filling stent-graft is deployed in parallel to the primary stent-graft. The gutter filling stent-graft includes a balloon that is pressurized and inflated by the patient's own blood thereby sealing any gutters formed around the gutter filling stent-graft. By sealing the gutters, the chance of type I endoleaks, migrations, and overall failure to exclude the aneurysm is minimized.