The basic principle of coronary artery stenting is to place a balloon catheter through a vascular puncture into the stenosed blood vessel and expand the balloon under pressure outside the body to open up the stenosed vessel wall and restore the diseased vessel. 1-2 stenoses and easy to place stents can be chosen for interventional treatment. Indications for coronary artery stenting (PCI) (1-2 stenoses and easy to put stents can choose interventional treatment) 1. acute myocardial infarction 2. angina pectoris (stable and unstable) with poor results of medical treatment and coronary angiography suggesting that the vessel has more than 75% stenosis.