Coronary artery perforation is one of the rare but serious complications of PCI, with an incidence rate of 0.1%~2.5%, which can cause acute cardiac tamponade, acute myocardial infarction requiring emergency coronary artery bypass grafting, and so on, and can jeopardize the life of the patient if it is not detected in time and handled inappropriately. （Coronary artery perforation is usually divided into three types (Ellis classification): Type Ι: extracavitary ulcerated niche, but no contrast extravasation; Type II: pericardial or intramyocardial contrast visualization; Type III: continuous contrast extravasation through the perforation or injection of contrast into the anatomical chamber. (ii) Causes There are lesion factors, device factors, and technical factors. Lesion factors include chronic occlusive lesions, calcified lesions, severe tortuous and angular lesions, and a high risk of coronary perforation during PCI. Instrumental factors include improper use of guidewires, balloons, and stents, as well as the use of special techniques such as cutting balloons, rotary cutting, and rotary grinding. Technical factors are mainly due to inexperience of the operator, errors in the choice of instruments used and inadequate judgment of the lesion. (III) Prognosis Coronary artery perforation can lead to cardiac tamponade, coronary ventricular fistula, myocardial infarction, emergency CABG and even death.Type I and type II perforations generally do not lead to fatal consequences, whereas improper or untimely management of type III perforations can lead to death (0-9%). (iv) Management The specific principles of management of coronary artery perforation during PCI vary according to the type and location. Type Ι perforation usually requires no treatment, and the hemodynamic status should be strictly observed; type II perforation should be immediately delivered to the perforation site using a balloon to seal the breach with continuous expansion at a pressure of 2-6 atm, and the expansion time should be determined according to the patient’s tolerance for 10-30 minutes. If the patient cannot tolerate it, the balloon can be loosened for 1 minute and then continuously dilated until the perforation is confirmed to be free of contrast extravasation. The pros and cons should be weighed together to determine whether to use cavitriol. Aspirin with clopidogrel is usually used nonstop. Type III perforations often do not heal with sustained balloon dilatation, so hemostasis with sustained balloon dilatation should be performed first, along with aggressive measures. (1) Membranous stent: It consists of two layers of 316 stainless steel tubular sculptured stent with one layer of polytetrafluoroethylene (PTFE) sandwich.Jomed Jostent provides five lengths of 9mm, 12mm, 16mm, 19mm, and 26mm, with diameters ranging from 3.0 to 4.0mm (can be expanded to 5.0mm). The membrane stent is easy to operate and has a high success rate in treating coronary perforation. Limitations: the band membrane stent is less pliable, and it is often difficult to reach the target site in calcified or twisted lesions; releasing the band membrane stent will lead to occlusion of the side branch at the perforation site; there is a possibility of increased risk of delayed thrombosis after the use of the band membrane stent; restenosis after implantation of the band membrane stent is similar to that of bare metal stent, and it is mostly located at the edge of the stent. (2) Autologous vascular graft covered stent: Generally, autologous radial artery, anterior elbow vein, cephalic vein or hand vein are taken, sutured and fixed on tubular stent, and then released on the perforation site by percutaneous method, so as to achieve the effect similar to that of band-membrane stent. Advantages: good biocompatibility and rapid endothelialization; Disadvantages: time-consuming operation, greater surgical trauma, need for large lumen guide catheter, etc. (3) Embolization therapy: It is suitable for perforation of the distal end of the vessel caused by innervating less surviving myocardium or smaller diameter vessels or distal segments of vessels, vessels close to complete occlusion lesions or guidewires. Micro-spring coils, gelatin sponges and thrombin can be used. (4) Emergency surgical repair: Surgery is suitable for patients with large perforations, combined with severe ischemia, hemodynamic instability or ineffective non-surgical treatment, and should be accompanied by coronary artery bypass surgery. Treatment of cardiac tamponade: Once hypotension occurs after coronary artery perforation, pericardiocentesis should be performed immediately when the blood pressure cannot be maintained by supplemental colloid or crystalloid fluid. Specialized pigtail catheter or deep vein indwelling catheter can be used. If the bleeding volume is large and fast, part of the blood drawn from the pericardium can be replenished directly into the body through the femoral vein. In cases where the coronary perforation has been closed, a single pumping is often sufficient, and the catheter should be retained in place for 24 hours and removed after confirming that there is no active bleeding. If the bleeding rate is very slow, it is often not necessary to block, and continuous drainage should be left in place to observe the drainage flow. If the drainage flow gradually decreases, there is no need to treat the vessel. If the drainage flow does not decrease or increases, the cause of the problem should be actively investigated and treated.