Interventional catheter assemblies that operate over a guide wire and incorporate guide wire management systems are disclosed. Specifically, a guide wire buffer zone is provided between a proximal end of the interventional catheter and the guide wire clamp that accommodates variable lengths of exposed guide wire in an unrestrained condition when the guide wire is clamped, allowing the distal end of the operating catheter to be advanced and retracted over the distal end of the guide wire without repositioning and reclamping the proximal end of the guide wire. The configuration of the guide wire buffer zone may be adjusted prior to or during an intervention based on the anticipated range of axial motion of the catheter and operating head relative to the guide wire.