The heart is like the engine of a car, beating day and night to deliver nutrients and oxygen to our body. When other organs in your body are diseased and require surgery, the heart also has to endure the shock of surgery. It is common to hear of patients dying of heart attacks during non-cardiac surgery. Technically, the surgery was successful, but the patient was killed or disabled because of the heart, which is certainly not what the patient or the surgeon wanted to achieve. During the perioperative period, anesthetic drugs and surgical blows can cause platelet aggregation and adhesion, which can easily form blood clots and lead to heart attacks and, in severe cases, death. Therefore, it is very important for physicians to perform a thorough cardiac evaluation and proper treatment of the patient prior to surgery. However, not all patients need to do so. Patients who are young, have no predisposing factors for heart disease, and exercise regularly are at low perioperative cardiac risk and generally do not require a preoperative cardiac workup, but patients who are advanced in age or known to have heart disease require extra attention. The physician must take into account the patient’s general health status, exercise tolerance, and associated diseases (e.g., renal failure, diabetes) to assess the risk of anesthesia. Patients with cardiovascular disease who require non-cardiac surgery must not be rushed into it. Doctors need to think twice before proceeding, weighing the need and urgency of the procedure, the patient’s tolerance level and intraoperative safety, and try to protect the heart’s function, or at least ensure that the heart problem will not worsen during the procedure. The five steps of the preoperative evaluation A multidisciplinary preoperative consultation provides an additional layer of protection for the patient. Surgeons often ask cardiologists to work with anesthesiologists to perform a cardiac evaluation of high-risk patients prior to surgery. An effective preoperative evaluation includes the following five major steps: i. Determine the urgency of the procedure If the patient’s condition is urgent and surgery is imperative, the surgeon will briefly assess the cardiac condition and administer the necessary cardiac-specific medications, including the patient’s hemodynamic status, blood tests, and electrocardiogram. Surgery takes precedence over saving the patient’s life. Further detailed examination of the patient will be taken during the post-operative recovery period to rule out any deviation in cardiac assessment due to surgery, blood loss, etc. II. Determining if you have unstable or active heart disease Not all patients with heart disease are at high risk when undergoing surgery. In fact, with today’s advanced anesthetic drugs, paired with an experienced surgical team, the risks of surgery have been reduced to very low levels. However, some patients with severe heart disease, such as unstable angina, recent myocardial infarction, severe heart failure, malignant arrhythmia or severe heart valve disease, should delay or even cancel surgery until the heart disease is clearly diagnosed and effectively treated before surgery can be considered to “turn the risk into safety”. Such patients require cardiac ultrasound scans, exercise stress tests, coronary angiograms, and other tests. Once the diagnosis is clear, targeted treatment (drugs or even devices) is implemented to ensure the safety of the surgery. In short, the surgeon needs to weigh the consequences of delaying surgery against the risk of perioperative cardiac deterioration and make a reasonable judgment. Non-cardiac surgery varies in terms of the degree of risk 3. If it is a low-risk surgery, such as endoscopic treatment, skin treatment, cataract surgery, breast surgery or surgery that does not require bed rest, it can be performed safely without concern even for high-risk cardiac patients. Their surgery-related disability and mortality rates do not exceed 1%. In contrast, the chance of cardiac complications for medium-risk surgeries such as head and neck, orthopedic, and prostate surgeries is 1-5%. High-risk surgeries such as aortic or peripheral vascular surgery have a much higher chance of risk and require extra care just in case. Determining the patient’s systemic status The patient’s systemic status is a reliable indicator of whether an adverse cardiac event will occur in the perioperative period. Patients who are fit and strong can generally withstand the risks of surgery and anesthesia. Usually we use metabolic equivalents (METS) to evaluate a person’s physical activity capacity. The higher the metabolic equivalent, the better the functional status of the body and the lower the risk of surgery. Patients who are able to do more than 4 METS are generally able to tolerate surgery and anesthesia. These activities include stair climbing, heavy housework (moving furniture, mopping floors), and exercise (walking at 7 km/hour, doubles tennis, table tennis, etc.). Activities less than 4 METS included driving (2 METS), washing dishes (2-4 METS), and walking at less than 5 km/hour. Those with a physical fitness status of less than 4 METS are at risk for surgery and anesthesia. On the contrary, those patients who can engage in more than 10 METS, such as swimming, playing tennis alone, playing basketball, playing soccer, etc., their physical fitness status is excellent, and the risk of surgery is extremely low, so they can operate safely and rest assured. V. Determination of the need for preoperative medication For those with poor general status or insignificant symptoms, surgery can be performed as planned if there are no clinical risk factors (including smoking, diabetes, hypertension, etc.). If there are one to two or even three or more clinical risk factors, if the procedure is to be performed at intermediate risk (perioperative mortality is expected to be 1%-5%), the surgeon may use medications (e.g., beta-blockers) to control the heart rate and protect the heart, and may even require preoperative non-invasive cardiac testing, such as exercise stress test, cardiac ultrasound scan, etc.