Cardiac angiography is the gold standard for the diagnosis of coronary artery disease. It is usually entered from the radial or femoral artery route, in which a small needle hole is made, and then a catheter, which is about 1.5 mm, is delivered to the vessel through the puncture point. The opening of the coronary arteries is performed from the radial, brachial, and subclavian arteries to the heart, and then contrast is injected into the left and right coronary openings, respectively, to show whether or not the entire coronary artery is blocked, or to what extent. Finally, a diagnosis of coronary artery disease is given to assess how much damage is actually done and to provide a direction for treatment. The choice of drug therapy, stenting or bypass is closely related to the results of the angiogram. Coronary angiography has certain indications for surgery, as follows: 1. When there are typical symptoms of coronary artery disease, the degree of coronary artery lesion should be determined by coronary angiography to determine whether further treatment is needed; 2. When there are atypical symptoms such as chest tightness, chest pain or wheezing, it is also necessary to do differential diagnosis by coronary angiography to determine and exclude the diagnosis of coronary artery disease; 3. For patients who have already had interventional treatment, it is necessary to clarify through coronary angiography For patients who have already undergone interventional treatment, coronary angiography is needed to clarify whether the lesion has progressed or to assess the current situation after stent implantation; 4. For people with special types of work, coronary angiography is sometimes needed to clarify the extent of coronary artery lesions. Angiography is a very safe test and patients should not worry, there is almost no damage, i.e. not much damage to the kidneys and heart. Some patients may worry whether the guidewire will cause damage to the blood vessels. In fact, the guidewire is called super smooth guidewire, commonly known as mudskipper guidewire, which can pass very smoothly in the blood vessels with almost no resistance and will not cause damage to the blood vessels.