A medical treatment system and method of treatment is described having an implant that can be positioned and deployed, then undeployed to allow repositioning of the implant. The system includes a self-expanding medical implant that longitudinally foreshortens upon radially expanding from a radially compacted state, a distal interface configured to attach the implant to a distal mount of a delivery device, and a proximal interface configured to attach the implant to a proximal mount of the delivery device. Moving the distal mount longitudinally away from the proximal mount applies a longitudinal tension to the implant causing the implant to expand longitudinally and contract radially, and moving the distal mount toward the proximal mount reduces a longitudinal tension in the implant allowing the implant to expand radially toward a fully expanded state.