Implantable medical devices for connecting tissue layers, such as forconnecting agallbladder and a portion of a gastrointestinal tract to create ananastomosis, include atubular structure having a plurality of apposition portions, a central region,and a coveringmaterial. The devices are endoscopically deployable and include flange membershavinghinge members of variable properties such as length, angle, shape, materialstiffness, andwire diameter.