A sterile hand-held device intended for use during guidewire-assisted intravascular interventional procedures [e.g., percutaneous transluminal coronary angioplasty (PTCA)] to facilitate the exchange of one catheter for another (e.g., coronary angioplasty balloon catheter) while maintaining the position of the guidewire. It consists of a clip for mechanical attachment to part of the catheterization device set, and a magnetic channel through which the catheter/guidewire is passed to enable removal of the catheter while the metal guidewire is magnetically held in place. This is a single-use device.