A coronary predilatation and stent deployment catheter assembly includes a sheathless unitary catheter body having a proximal end and a distal end. A predilatation balloon is located at the distal end of the body. A stent inflation balloon is located along the body proximally of the predilatation balloon and an expandable stent is disposed over the stent inflation balloon. A predilatation balloon inflation connection is located proximally of the stent inflation balloon and in fluid communication with the predilatation balloon and a stent balloon inflation connection is located proximally of the stent inflation balloon and in fluid communication with the stent inflation balloon. A method of operating the catheter assembly is also disclosed.