A delivery device includes a handle, a central elongate member extending from the handle, a sheath configured to slide over and relative to the central elongate member, a distal tether retainer at a distal end of the central elongate member, a proximal tether restraining mechanism positioned along the central elongate member distal of the handle and proximal of the distal tether retainer, and a plurality of tethers. The tethers are configured to extend from the proximal tether restraining mechanism to the distal tether retainer.