The course of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) has been controversial. Why is it necessary to insist on dual antiplatelet medication after PCI? Here we share the necessity of taking dual antiplatelet agents after PCI for your reference. 1.Concept of PCI Percutaneous coronary intervention (PCI), previously known as percutaneous coronary angioplasty, refers to the treatment method of dilation of stenosed coronary arteries through various methods via catheter so as to lift the stenosis and improve myocardial blood supply. The procedure is performed by puncturing a blood vessel (radial artery at the wrist or femoral artery at the base of the thigh), allowing the catheter to travel through the vessel to the opening of the coronary artery, and then using a special delivery system to place the stent in the desired location, then placing the stent and withdrawing the catheter. 2.Why is PCI performed? Due to coronary atherosclerosis and thrombosis, coronary artery stenosis or occlusion, the patient has insufficient blood supply to the heart, myocardial ischemia and necrosis, and due to cardiac hypoperfusion, the patient has intermittent or continuous chest pain and/or chest tightness. Through percutaneous coronary intervention, the narrowed vessel wall is propped up through the placement of stents, which promotes smooth blood flow and effectively improves the blood supply to the heart, thus relieving the patient’s symptoms of chest pain and chest tightness. 3.Does it mean that everything is fine after the surgery? Many patients have poor compliance and are not accustomed to taking medication regularly for a long period of time. They think that they have already undergone PCI surgery, the coronary vessels are protected by stents, the vessels will not narrow again, and they can stop taking medication after a period of time. This is a misconception. PCI only temporarily solves the problem of stenosis of diseased vessels, it is not a foolproof technology, and some patients will suffer from restenosis after stenting. In addition, stents are mostly made of stainless steel or alloy materials, and for the body, the stent is a foreign body, the body has a rejection reaction, and in the process of its placement, the endothelium is damaged due to friction, the endothelium is damaged, the body’s coagulation mechanism is activated, platelet aggregation reaction, play its anti-coagulant effect, to plug the wound, another thrombus will be formed. Some studies have shown a restenosis rate of 20%-30% within 6 months after metal stenting. With the advancement of technology, drug-eluting stents have been introduced, which have further reduced restenosis (below 10%) after stent placement. However, it still causes a high incidence of in-stent thrombosis. Therefore, postoperative in-stent restenosis remains a major problem, and thus the year after PCI is the peak period for in-stent restenosis to occur. PCI deals with the vessels that have the greatest impact on the patient, i.e., it only deals with the major large vessel lumens with stenosis greater than 75%; for some small vessels with less severe stenosis or some small vessels that need to be treated or not, the problem of atherosclerosis still exists, which means that the patient’s vessels may be stenosed again, leading to a recurrence of heart attack and sudden death. It is important to know that patients who have had an episode of myocardial infarction have 3 to 5 times the risk of another heart attack than ordinary people. 4.What are the ways to reduce the occurrence of thrombus? The initiating factor of thrombosis is platelets. This is when we need to do something to discourage platelets from being so aggressive to repair the damage, and we can let the endothelial cells of blood vessels grow slowly on their own. And by what means? By taking antiplatelet medications, more commonly known as aspirin, but also in combination with another antiplatelet drug, clopidogrel (or tigretol). Post PCI patients need to take aspirin 100mg once daily (preferably on an empty stomach if it is an enteric tablet) and clopidogrel 75mg once daily (or tigretol 90mg twice daily) for at least 1 year, and 6 to 12 months, which can greatly reduce the risk of in-stent thrombosis, reduce the incidence of re-infarction, and reduce the risk of risk of death for patients. Adherence to the medication is required unless there is easy bleeding or if the medication is not tolerated. Taking anticoagulants requires monitoring the clotting time and observing the patient’s condition, for example, observing the skin for petechiae and bleeding spots, gum and nasal bleeding, black stool, hematuria and severe headache, etc. If these manifestations occur, the patient should seek prompt medical attention. If invasive operations are performed (such as tooth extraction), the doctor needs to be informed that antiplatelet drugs are being taken. Experts recommend that even if patients who have undergone PCI insist on taking antiplatelet drugs every day, these patients should undergo coronary angiography again 1 year after the operation to check the condition of the vessels and stents to be able to better understand their condition and adjust their treatment plan in time.