Atherosclerosis is the most important cause of coronary artery stenosis. This is a pathological process called “atherosclerosis”, which usually begins in childhood and continues throughout a person’s life. This pathological process is called “atherosclerosis” and usually begins in childhood and continues throughout a person’s life. To use a more common analogy, it is like a water pipe, if there is constantly something dirty gradually attached to the pipe wall, slowly more and more, eventually it will lead to thinning of the water flow, and very rarely even stop the water. Atherosclerosis does not occur only in the coronary arteries, but in arteries throughout the body, causing stenosis. Many patients who undergo preoperative ultrasound will find sclerotic plaques and even resulting stenoses in the carotid, vertebral, and renal arteries for this same reason. As the plaque gradually increases and thickens, it may block the coronary artery and gradually reduce the blood supply to the heart. When the plaque blocks 70% or more of the diameter of the coronary artery, ischemia and hypoxia will occur in the heart muscle, manifesting as chest pain, chest tightness, breath-holding and discomfort in the precordial area, which is called “angina pectoris”. It can be relieved by rest or sublingual nitroglycerin, but in severe cases, it can also occur at rest or even during sleep. Many patients say that they have never had angina, but only some chest tightness or “unexplained discomfort” in the precordial region, so how can it be angina? In fact, the attack of angina is not necessarily “pain”, most people do not “pain”, only the above-mentioned “chest tightness, discomfort”, and some patients manifest as “Stomach pain”, “toothache”, “sore throat”, “tightness in the throat” “left shoulder and arm pain”, or even just weakness, etc. There are even patients who have no symptoms at all, but only have ECG or cardiac ultrasound abnormalities found during physical examination, and are found to have severe coronary artery disease only after coronary angiography. However, in such patients, the majority of patients have had discomfort after careful questioning of their medical history, only that it was not serious and did not attract enough attention. No matter how different the symptoms are, coronary angiography is the “gold standard” for the diagnosis of coronary heart disease, and if there is a problem with the angiography, it is coronary heart disease. The current popular “coronary CT” examination can only be a preliminary screening, not a final definitive diagnosis, nor can it be the basis for the need to put stents and bypass. Then, the plaque may rupture and cause acute thrombosis, resulting in acute occlusion of the coronary artery, called “acute myocardial infarction”. Patients may experience persistent chest pain or discomfort in the precordial region, radiating to the back, left forearm or throat, which cannot be relieved by rest or sublingual nitroglycerin. The coronary arteries are divided into the left coronary artery and the right coronary artery, of which the left coronary artery divides into the anterior descending branch and the gyrus branch after the shorter left main stem. What we usually call “triple lesion” means that the anterior descending branch, the circumflex branch and the right coronary artery are narrowed. Why is the “left trunk lesion” considered to be more severe? As you can see from the figure below, the left trunk (the location of the “left coronary artery” in the figure below) is located at the source of the left coronary artery, just like a blocked water source dries up all areas downstream.