| abstract |
A medical appliance of shape memory material is provided for implantation in a vascular passageway for engagement with the walls of the passageway. The appliance includes a body formed of thermal shape memory material having a temperature transformation level below which the body is in a martensitic state and is pliable and compressible, and above which the body is in an austenitic state and is self-expandable to a substantially rigid pre-compressed configuration. The shape memory material in the austenitic state is capable of being transformed by stress to the martensitic state. The body includes segments which expand outwardly away from the longitudinal axis of the body in the austenitic state thereof, and a superelastic hinged joint is formed in at least one of the segments by reducing the cross-sectional area of the segment in a localized area. |