Cardiac angiography is an invasive test that is not dangerous, but there may be allergic reactions to the contrast agent injected into the body, that’s all. The main purpose of this test is to determine the extent of coronary artery stenosis and to determine whether or not to install a stent. The radial artery is usually punctured, an arterial catheter sheath is placed, a guidewire is inserted, and a contrast medium is injected into the coronary artery opening. Because of the difficulty of placing the radial artery sheath, it is necessary to place it through the femoral artery. If the vessel is abnormally shaped or severely tortuous, the entire operation may take longer, but it is not harmful to health. If the stenosis is severe, it is eligible for stenting. Angiography is a routine test and is not harmful to the body.