A main stent member, e.g. a stent graft (20), has an opening (25) which is sealingly connected to a secondary stent member (27) by means of an elastic tubular bridging element (30). The bridging element may taper, have walls of varying thickness and/or incorporate reinforcing fibers. The opening (25) may be a fenestration along the length of the graft (20) or at a bifurcation (62, Fig. 9) at one end of the graft.
