Catheter system with catheter and guidewire exchange

An intravascular catheter system, such as a dilatation catheter system for angioplasty procedures, which provides for the replacement of the catheter or the guidewire during the procedure. The intravascular catheter has a guidewire-receiving inner lumen extending along its length. A first guidewire port is provided in the catheter body at or near the proximal end of the catheter. A second guidewire port is provided in the catheter body at a location spaced distally from the first guidewire port and proximally from a diagnostic or therapeutic tool, such as a dilatation balloon, on a distal portion of the catheter. A third guidewire port is provided in the distal end of the catheter. The guidewire ports are in communication with the guidewire-receiving inner lumen.