A stent-graft (20) comprises strut members (30) and a graft member (32), which is fixed to the strut members (30). The strut members (30) and the graft member (32) are arranged so as to define, when the stent-graft (20) is in a radially-expanded state: a main tube (40), which is shaped so as to define a main lumen (42)； and a lateral tube (50), which (a) has (i) a distal end (52) and (ii) a proximal end (54) that is joined to a lateral wall (56) of the main tube (40) at a junction (60), (b) is shaped so as to define a lateral lumen (62) that is in fluid communication with the main lumen (42), and (c) defines a central longitudinal axis (64). The strut members (30) that define the lateral tube (50) are shaped so as to define two to four non-contiguous arcuate members (70), which (a) are centered around the central longitudinal axis (64)； and (b) collectively subtend at least 150 degrees around the central longitudinal axis (64).
