An introducer system for deploying an implant in a lumen of a body, comprising: an implant comprising: a proximal end and a distal end; a lumen extending between the proximal end and the distal end; a first segment having a constrained configuration and an expanded configuration; a second segment having a constrained configuration and an expanded configuration adjacent the first segment; a carrier to which the implant is mounted; and a constraining mechanism constraining the first segment, including a first release wire (42,42') and circumferentially spaced wire-receivers (140 A, B, C), the wire-receivers attached to the first segment and extending inwardly from an inner surface of the first segment and releasably engaged to the first release wire; wherein the wire-receivers (140 A, B, C) and the first release wire (42,42') together radially constrain the first segment of the implant in its constrained configuration; wherein in a first configuration of the implant, the second segment is expanded and the first segment is constrained, and in a second configuration of the implant, both the first and second segments are expanded; and characterised in that the engagement between the release wire (42, 42') and the wire receivers (140 A, B, C) is such that the wire receivers are inhibited from sliding independently relative to one another. an implant comprising: a proximal end and a distal end; a lumen extending between the proximal end and the distal end; a first segment having a constrained configuration and an expanded configuration; a second segment having a constrained configuration and an expanded configuration adjacent the first segment; a proximal end and a distal end; a lumen extending between the proximal end and the distal end; a first segment having a constrained configuration and an expanded configuration; a second segment having a constrained configuration and an expanded configuration adjacent the first segment; a carrier to which the implant is mounted; and a constraining mechanism constraining the first segment, including a first release wire (42,42') and circumferentially spaced wire-receivers (140 A, B, C), the wire-receivers attached to the first segment and extending inwardly from an inner surface of the first segment and releasably engaged to the first release wire; wherein the wire-receivers (140 A, B, C) and the first release wire (42,42') together radially constrain the first segment of the implant in its constrained configuration; wherein in a first configuration of the implant, the second segment is expanded and the first segment is constrained, and in a second configuration of the implant, both the first and second segments are expanded; and wherein the wire-receivers (140 A, B, C) and the first release wire (42,42') together radially constrain the first segment of the implant in its constrained configuration; wherein in a first configuration of the implant, the second segment is expanded and the first segment is constrained, and in a second configuration of the implant, both the first and second segments are expanded; and characterised in that the engagement between the release wire (42, 42') and the wire receivers (140 A, B, C) is such that the wire receivers are inhibited from sliding independently relative to one another.