A device for facilitating treatment of a blood vessel comprising a handle assembly (134) including a handle housing (138) and a handle axle (140)； a shaft extending through the handle assembly, wherein the handle axle is selectively fixed to the shaft； the handle assembly comprising a torque control mechanism (154) including a first camming element (156) coupled to a distal portion of the handle axle, a second camming element (158), and a distal cap (142)； wherein rotation of the handle housing in a first direction about a longitudinal axis of the shaft causes rotation of the shaft in the first direction when torque applied by the handle housing to the shaft is below a first maximum torque； wherein rotation of the handle housing in a second direction about the longitudinal axis of the shaft causes rotation of the shaft in the second direction when torque applied by the handle housing to the shaft is below a second maximum torque.
