It is often asked by patients’ families before undergoing cardiac surgery how dangerous the surgery is or what the success rate of the surgery is, and this is a question that is difficult to answer at once, especially for more critical patients. Because the statistical methods of medical science often calculate surgical mortality and survival rates from large groups of cases, there is again a multifactorial analysis. A specific case cannot be answered with a percentage. If the success rate is 99%, there is still a 1% unsuccessful rate; but when this one percent happens to a specific person, it is still a 100% failure for that person. Cardiac surgery is a complex surgical technique, with the vast majority of procedures requiring extracorporeal circulation and cardiac arrest. If a person has a heart condition that requires non-cardiac surgery, or is undergoing a normal birthing process, even though it may not be a complex procedure such as an appendectomy, it can make the procedure or surgery less dangerous. It is understandable that surgery on a structurally and functionally compromised heart, which requires cardiac arrest and post-operative recovery of the heart’s pumping function, can have varying degrees of surgical risk, whether the heart surgery is simple or not. Not every patient undergoing cardiac surgery can encounter these risk factors, and the occurrence of these risk factors is mostly related to the patient’s preoperative status, cardiac function and severity of the disease, as well as the cause of the patient’s heart disease, the duration of the disease and other important organs. The risk factors are related to the patient’s preoperative baseline status, cardiac functional status, severity of the disease, as well as to the etiology, duration and functional status of other important organs. To use an analogy from daily life, if you are asked to wrap dumplings with rich flour, you can guarantee that none of them will break; however, if you are asked to wrap dumplings with other poor quality flour, it will be difficult to determine whether a rupture occurs, which one will break, and how many will break, even though you have carefully wrapped each one. The patient’s physical condition, the functional quality of the heart, and the nature of the disease are the main factors that influence the risk of surgery. Common surgical risks include anesthesia accidents, bleeding, cardiac arrhythmias, extracorporeal circulation accidents, cardiac failure, renal failure, respiratory failure, liver and other internal organ failure or dysfunction, cerebrovascular accidents, and infection. Any of the above serious conditions can be fatal. Whether in China or abroad, the training of cardiac surgeons often takes many years after medical school graduation (usually 5 to 8 years or even longer) before they begin to mature, and more complex cardiac surgery is mostly done by experienced surgeons. In our large medical centers and hospitals, the mortality rate for the vast majority of surgical treatments for heart disease has been similar to that of developed countries, but the late timing of medical care for our patients and the fact that many diseases have progressed to very serious levels is an important factor that increases the risk of surgery and affects surgical mortality. The technical errors that occur in individual cases or the lack of necessary experience and condition equipment are sometimes factors that cause surgical failure.