a temporary filter is described for use in percutaneous intravascular procedures for the treatment of diseased blood vessels , such as angioplasty or stent placement procedures . the guide wire which is used to direct a catheter to a treatment site contains a deployable filter . the guide wire is moveable independently of the catheter and can be used to position the filter at a desired location downstream of the treatment site . the guide wire includes parts moveable with respect to each other and the filter is connected to these parts in such a way that it can be deployed and collapsed by relative movement of the parts .