Coronary artery disease (CAD) can be diagnosed in several ways. For some people, a heart attack is their first clue that the arteries in the heart are blocked. For many others, however, symptoms such as chest pain prompt an evaluation of the heart, which leads to the discovery ofCAD. One of the most well-established and accurate diagnostic tools is coronary angiography. In this procedure, a thin, flexible catheter is threaded through a blood vessel and into your heart.