A cuff assembly for placement around a body vessel comprises a cuff member sized to substantially surround the body vessel, and a tether assembly engaged with the cuff member. The tether assembly is sized to at least substantially encircle the cuff member, and includes a locking mechanism for releasably maintaining a selected tension when the tether assembly encircles the cuff member. The tether assembly may comprise a tether and a tab, wherein the tab is engaged with the cuff member and has an aperture therethrough. The distal end of the tether is engaged with the tab. The locking mechanism may comprise a plurality of stop members disposed along a surface of the tether. The stop members are sized relative to the aperture to enable passage of at least a portion of the tether therethrough to encircle the cuff member when the stop members are aligned at a first angle relative to the aperture, and to substantially fix a position of the tether at a tension around the cuff member when the stop members are aligned at a second angle relative to the aperture.