Coronary angiography is an x-ray examination of the coronary arteries, which are the tubes a few millimetres wide that lie on the outside surface of the heart and take blood to the heart muscle. Just as an engine needs petrol, the heart needs blood to do its job of pumping blood around the body.
Slow build-up of fatty plaque within the artery wall can cause the artery to narrow, leading to reduced blood flow. Sudden changes in the plaque may cause angina (a sudden intense pain in the chest caused by momentary lack of adequate blood supply to the heart muscle) to worsen or may cause a heart attack.
During coronary angiography, a tiny plastic tube called a catheter is introduced under local anaesthesia into your wrist or groin artery. Your cardiologist watches the catheter on an x-ray screen as they pass the tip of the catheter to one of the coronary arteries that lie on the surface of your heart. A special fluid (contrast or dye) which is visible on the x-ray imaging is injected into the coronary arteries and movie pictures of the arteries are recorded. These x-ray pictures of your arteries will show any narrowings that may reduce flow of blood to your heart muscle.
Other tests performed during the coronary angiogram include measuring pressures within the heart chambers, checking function of some of the valves and checking how well the heart muscle is pumping.
Where a narrowing is identified in a coronary artery during a coronary angiogram, the cardiologist may treat the lesion using a stent (fine mesh tube). This is known as Percutaneous Coronary Intervention (PCI) also called coronary angioplasty, which means ways of opening narrowings in coronary arteries using fine tubes called catheters introduced from the wrist or groin.
The first image shows a normal Left Coronary Artery (LCA) which supplies blood to the left side of the heart. The second image shows disease (arrows) in the Right Coronary Artery (RCA) which supplies blood to the right side of the heart.