Embodiments include a catheter comprising an elongated, a laser delivery member, and a handle having an actuation mechanism coupled to the laser delivery member. In some embodiments, the actuation mechanism comprises: a body including a distal disc and at least one release arm a plunger including a proximal disc, the plunger disposed at least partially within the body where distally advancing the plunger includes depressing the proximal disc and the distal disc to advance the laser delivery member and a moveable lock feature operatively connected to the body, whereupon: in a first position, the moveable lock feature is configured to prevent the at least one release arm being depressed to retain the laser delivery member in an advanced position and in a second position, the moveable lock feature is configured to permit the at least one release arm being depressed to retract the laser delivery member to a retracted position.
