Endoprosthesis for controlled contraction and expansion

An endoprosthesis, comprising:

• a plurality of annular elements, each annular element connected to an adjacent annular element at least one connection location;
• each annular element including an interconnected series of strut members, at least one strut member connected to a first circumferentially adjacent strut member at a first longitudinal apex and to a second circumferentially adjacent strut member at a second longitudinal apex, the first apex and the second apex being on longitudinally opposite sides of the annular element;
• the at least one strut member including:
• a first end portion at a first end of the strut member, the first end extending to the first apex,
• an intermediate portion hingedly connected to the first end portion, and
• a second end portion hingedly connected to the intermediate portion and extending to the second apex;
• and
• wherein the endoprosthesis has a delivery diameter when in a delivery condition and a deployed diameter when in a deployed condition.