A medical device system may include a sheath, a pusher wire, and a locking element. The sheath may have a first outer diameter adjacent to the proximal end and an enlarged outer diameter region having a second outer diameter greater than the first adjacent to the intermediate region. The pusher wire may be slidably disposed within a lumen of the sheath. The locking element may have a lumen extending therethrough. The locking element may have a first inner diameter adjacent to the distal end and a second inner diameter smaller than the first adjacent to the intermediate region. The locking element may configured to freely slide over a region of the sheath having the first diameter. When the locking element is disposed over the enlarged outer diameter region of the sheath having the second outer diameter, the locking element may be configured to depress the sheath radially inwards.
