A coronary angiogram is an X-ray imaging test used to locate impairments of the heart or blood vessels, Mayo Clinic states. Physicians perform the procedure by injecting contrast dye into a blood vessel and using an X-ray machine to take pictures and determine where blood flow may be blocked.
Angiograms are commonly performed on patients suffering from a recent heart attack, aortic valve constriction or chest pain, known as angina, according to MedlinePlus. Doctors may also use the test to screen high-risk patients before proceeding with cardiac surgery. An angiogram requires catheterization, a process that involves threading a hollow tube, known as a catheter, through an artery in the arm or groin to reach the heart. The catheter is used to administer the dye, which travels naturally through the bloodstream and gives physicians clearer images of blood circulation in the affected area. Although the procedure doesn't normally cause pain, the patient is usually given a sedative for relaxation, and the test lasts about 30 to 60 minutes.
A coronary angiogram can help doctors determine whether harmful plaque deposits are blocking arterial pathways and measure how much the heart's efficiency at pumping blood has been decreased, Mayo Clinic explains. The test is also useful for monitoring patients after a cardiac surgery, such as a coronary bypass, to find out if blood flow is improving.