Patent ID: 8172863

Claim:
A device for facilitating treatment of a blood vessel, the device comprising: a shaft having a distal end and a proximal end; a handle assembly fixed about the proximal end of the shaft, the handle assembly including a first portion, wherein rotation of the first portion in a first direction about a longitudinal axis of the shaft causes rotation of the shaft in the first direction when a torque applied by the first portion to the shaft is below a first maximum torque; a first camming element having a protrusion that includes a first ramped surface and a second surface; and a second camming element having a wall, wherein rotation of the first portion in the first direction about the longitudinal axis of the shaft does not cause rotation of the shaft in the first direction when the torque applied by the first portion to the shaft is above the first maximum torque, wherein the first ramped surface is configured to allow the wall of the second camming element to pass over a top of the protrusion when the first camming element is rotated with respect to the second camming element in the first direction, and the second surface is configured to prevent the wall of the second camming element from passing over a top of the protrusion when the first camming element is rotated with respect to the second camming element in a second direction, wherein the shaft is an elongate shaft comprising one or more flexible elements, the shaft being configured to traverse along a blood vessel.