The guide catheter instructions clearly state that the guide catheter is indicated to assist in the introduction of a PTCA (Percutaneous Transluminal Coronary Angioplasty) dilatation catheter into the coronary arteries. It is used during coronary balloon dilatation or stenting procedures, through which a number of dilatation balloons, stents, etc. are delivered to reach the diseased area for the procedure. Sheaths, guide wires, guide catheters and many other instruments are required to perform coronary intervention. Among them, the introducer catheter is used when the stenotic lesion needs to be further treated with balloon dilatation or stent implantation. From the introducer catheter, a balloon or stent is introduced so that the balloon or stent can reach the lesion for pressure dilatation or stent implantation. After the vascular lesion has been treated, all catheters, guidewires, and other instruments are withdrawn. The guide catheter plays an important role in performing coronary balloon dilatation angioplasty or stenting.