An endograft comprising a proximal end and a distal end is disclosed. The endograft comprises a tube of biocompatible material. The tube comprises: a main lumen (16) extending longitudinally from the proximal end to the distal end, the main lumen (16) including a proximal portion, an intermediate portion and a distal portion； a branch lumen (36) within the intermediate portion of the main lumen (16) ； and a seam (40), the seam (40) extending longitudinally beside both the branch lumen (36) and the distal portion of the main lumen (16), wherein the tube comprises a lateral cross-section defining a tubular wall pinched together by the seam (40) to form a branch portion. The branch portion can comprise an entrance within the intermediate portion of the main lumen (16) and an exit through the tubular wall of the main lumen.
