What is coronary heart disease? The heart acts like a pump in the body’s circulatory system, pumping blood from the low-pressure veins to the high-pressure arteries. Just as a pump consumes electricity to move water from a well to a water tower, so the heart consumes energy to move the blood from low to high pressure. Where does this energy come from? This energy comes from the blood. Oxygen and glucose from the blood enter the heart muscle cells and undergo an oxidation reaction, which releases energy, and it is this energy that the heart uses to do its work. Therefore, the blood supply to the heart muscle is as important as the power supply to the pump. Once the blood supply to the heart muscle is blocked, even locally, it can affect the function of the heart. So, by what means does blood flow (medically called “perfusion”) to the heart muscle? The answer is through the coronary arteries. So the coronary arteries are like the “power lines” of the “pumps” in the human circulatory system that can never stop working, which shows their importance. The coronary artery is the first pair of branches of the aorta, which starts from the root of the aorta and is generally divided into two branches, the left coronary artery is divided into two major branches. This is the reason why doctors often say “three branches of coronary artery lesions”. The full name of coronary artery disease is coronary atherosclerotic heart disease. The basic lesion is that the atheromatous plaque in the coronary artery wall blocks part or all of the coronary artery lumen, causing the latter to narrow, resulting in blocked blood flow. When myocardial ischemia occurs, there are broadly three types of functional damage that may occur in cardiomyocytes. One is ischemia of the myocardial cells, resulting in a decrease in their contractility, while the patient has an angina attack. The second is myocardial cell necrosis, resulting in loss of contractile function of the myocardial cells, which is clinically known as myocardial infarction. Also, the necrosis of the tissue can lead to papillary muscle rupture, septal perforation or rupture of the ventricular wall. Third, the myocardial cells are in a state of “hibernation”, with neither necrosis nor contractile function. In the first and third cases, when the blood supply to the myocardium is restored, the contractile function of the myocardium can be restored. In the second case, the contractile function of the myocardium is lost forever. In other words, when myocardial ischemia occurs, the function of the heart is preserved and restored if the blood supply to the ischemic myocardium is restored in time; if myocardial infarction has occurred, the function of the heart is definitely damaged beyond recovery. Besides coronary arteries, do other blood vessels in the body have similar lesions? Yes. Atherosclerosis of the small and medium-sized arteries is a systemic disease, and the degree of lesions in each part of the system may be uneven, and coronary atherosclerosis is only part of this systemic disease. Lesions similar to coronary atherosclerosis can also occur in other parts of the body’s blood vessel walls, and there is a pattern that the higher the blood flow, the higher the probability of lesions occurring and the more severe they are. The importance of organs in the human body, from the point of view of sustaining life, is often related to the metabolic rate of the organ. The more important the organ, the higher its metabolic rate. A high metabolic rate translates into a high blood flow in the blood vessels that supply it. Organs of the body with high metabolic rates include the brain, heart, kidneys and retina. These areas are also where the incidence of small and medium-sized atherosclerosis is high. For example, the familiar cerebral infarction has almost exactly the same pathological basis as myocardial infarction. Clinically, there are few coronary heart patients with combined renal artery stenosis, carotid artery stenosis and cerebral infarction. How is coronary heart disease treated? The purpose of treating coronary heart disease is twofold: to prolong the life expectancy of the patient and to improve the quality of life of the patient. Currently, there are three methods of treatment for coronary heart disease. The first is pharmacological treatment, i.e. taking medication to control the symptoms, the main points are to dilate the coronary arteries, reduce the heart load and inhibit platelet aggregation. The second is percutaneous coronary intervention, which is often referred to as stenting. The third type is coronary artery bypass grafting, or coronary artery bridging. Human experience has shown that the immediate and long-term effects of drug therapy alone are significantly inferior to those of stenting and coronary artery bridging. Coronary artery bypass grafting and interventional stenting have their own advantages and disadvantages and are adapted to different conditions. In general, coronary artery bypass grafting has adequate recanalization, complete relief of myocardial ischemia, and good postoperative results, but is slightly more risky. Stents have the advantage of being less invasive and can be performed multiple times. However, its indications are narrow (especially not for lesions at the left main bifurcation, uncontrolled diabetic patients, and patients with other comorbid intracardiac pathologies requiring surgical treatment), and the probability of needing postoperative reintervention (i.e., bridging surgery or re-stenting) is 6-7 times higher than that of bridging surgery. Cost-wise, it may be more expensive than the cost of surgery if multiple stents are placed. In the United States, there were 253,000 coronary artery bypass procedures and 1,313,000 coronary stents in 2006 (CABG:PCI=1:5.2). In China, there were an estimated 14,000 coronary artery bypass surgeries in 2007 (140,000 cardiac surgeries, based on 10% of the total number of coronary artery bypass surgeries) and 144,673 coronary stents (CABG:PCI=1:10.3). It is not that all Chinese patients’ conditions are more suitable for stenting, nor is it that Chinese doctors are more skilled in stenting than foreign countries. The only explanation is that due to the high technical requirements of coronary artery surgery, many hospitals in China cannot meet the requirements of surgical treatment and have to put in stents. There are a large number of patients with stents that should not be put in but are put in. Not choosing the treatment method scientifically according to the condition causes the most damage to the patient. In 2009, there were 2,104 cases of coronary artery bypass surgery and 6,771 cases of percutaneous coronary intervention (1:3.2) in Fu Wai Hospital. What is the “bridge” used in bypass surgery? The “bridge” used in coronary artery bypass surgery is known in medical terms as a vascular bypass graft. If a vessel can be used as a coronary artery bypass graft, it should meet several requirements: be of sufficient length, be from a wide variety of sources, be obtained with minimal damage to the patient, and have a high long-term patency rate. The most widely available sources are artificial vessels or vessels from treated xenobiotics, but these are also the vessels with the lowest long-term patency rates, so they are not used clinically. The best patency rates are achieved when the patient’s own blood vessels from other sites are removed and used for coronary artery bridges. Autologous vessels are no more than autologous veins and autologous arteries. The vessels with the most sources and longest lengths on the body are the superficial veins of the lower extremities, namely the great and small saphenous veins. The most traumatic to the patient when obtained is the gastroretinal artery (open chest bypass along with an open abdomen to remove the vessel). The one with the highest long-term patency rate is the internal thoracic artery (also known as the internal mammary artery). Therefore, the more arterial bridges a patient receives, the longer the surgical relief of myocardial ischemia will last. Of course, the patient’s condition has to be taken into account in terms of the bridges used. Obtaining an arterial bridge is more invasive and the procedure takes longer. What should I expect after coronary artery bypass surgery? As we know from the previous section, coronary artery bypass surgery cannot cure coronary heart disease, but can only relieve myocardial ischemia due to coronary artery stenosis. The American Heart Association guidelines state that patients who undergo coronary artery bypass surgery have about a 50% chance of dying from coronary heart disease. The reasons for this are twofold: the continued development of atherosclerotic lesions in the coronary arteries themselves and new lesions and their development on the newly constructed vascular bridge. Therefore, how to slow down the progression of atherosclerosis after surgery becomes the main task of postoperative treatment. Lowering blood lipids, controlling blood sugar, controlling blood pressure, quitting smoking, and proper medication can all slow down the progression of lesions. Foods that patients should avoid after bypass surgery are: foods with high cholesterol, including: all kinds of animal offal, all egg yolks, fish roe, shrimp and crab (especially crab yolk), shellfish, scaleless sea fish (scallops, squid); foods with high fat, including all kinds of fried foods, avoid excessive intake of cooking oil; saturated fatty acids, mainly all kinds of animal fat, such as lard, butter, mutton oil, butter; foods with a large amount of trans Foods with a lot of trans fatty acids, such as cakes, pearl milk tea, ice cream, etc. An important complication of diabetes is the atherosclerosis of small and medium-sized arteries, which is associated with coronary heart disease in many patients. An important complication of diabetes is atherosclerosis of the small and medium-sized arteries, which is associated with coronary artery disease in many patients. Oral aspirin initiated within 48 hours of surgery and continued over time can significantly improve the long-term patency of venous bridges. Clopidogrel also has the effect of aspirin, but is more expensive to take long-term. Statin lipid-lowering drugs have been the most important advance in the pharmacological treatment of coronary artery disease in the last 30 years. Like aspirin, statins can significantly improve the long-term patency of venous bridges. The American Heart Association guidelines recommend that patients undergoing coronary artery bridging surgery for coronary artery disease without contraindications take statin lipid-lowering medications regardless of whether their lipids are normal after surgery. It is important to note that statins may have the side effect of liver damage, and in order not to interfere with early post-operative recovery, Fulbright Hospital generally recommends that patients start taking them one month after surgery (which is significantly different from the requirement for aspirin). It is important to pay attention to regular liver function tests after taking the drug, especially for patients who have not taken it before surgery. We have had cases of patients with liver function impairment after taking statins that were misdiagnosed as hepatitis by the local hospital.