A stent delivery system is disclosed for delivering and deploying a radially expandable stent at a strategic orientation and location in a body vessel. The delivery system includes an elongated flexible tubular shaft sized suitably for insertion into the body vessel. A stent deployment assembly includes a distal transition portion supporting a dilator device adapted for radial expansion about a longitudinal axis of the deployment assembly from a non-expanded condition to a radially expanded condition. The dilator device is configured to support the stent thereon in the non-expanded condition and in predetermined orientation relative the deployment assembly. A rotational clutch assembly rotatably mounts the transition portion to a distal portion of the tubular shaft such that the deployment assembly is substantially torsionally isolated from the tubular shaft, about a longitudinal axis of the clutch assembly. This enables the stent deployment assembly to rotate substantially independently of the tubular shaft for strategic orientation of the dilator device during advancement through the body vessel.