A stent graft for placement in a lumen of a patient is disclosed. The stent graft comprises a main body including a main lumen and having a distal end terminating in a bifurcation. It also comprises first and second legs extending from the bifurcation, the first and second legs having respective first and second leg lumens and the first and second leg lumens being in fluid communication with the main lumen and a side arm extending from the first leg, the side arm having a side arm lumen. The side arm lumen is in fluid communication with the first leg lumen at a position adjacent to the bifurcation. A combined lumen is formed. The combined lumen is between the main lumen and a distal portion of the first leg lumen and is bounded laterally by a portion of the side arm located adjacent to the bifurcation.
