Coronary angiography is a procedure where the coronary arteries are imaged. The coronary arteries are the blood vessels that supply the heart itself with blood. The heart, like any other muscle, needs oxygen to function. It gets this oxygen from the blood stream. The coronary arteries run along the surface of the heart and supply this oxygen-rich blood to the muscles of the heart. Over time the insides of the arteries can become clogged (and ultimately blocked), limiting or stopping the blood flow. This lack of oxygen and blood flow causes chest pain.
During the preparation for the procedure you will move from your bed to the x-ray table which is narrow and a little hard. You will then be connected to an ECG to monitor your heart beat. One of the nurses will then wash your groin area (which will have been shaved) with some antiseptic solution—this feels cold. You will then be covered with a big blue sheet from chin to over your toes. This is sterile to keep any germs from the access site. It is important that you do not touch the top of this sheet. Your arms will be down by your side and supported by some arm boards. Please don’t move them unless told to and someone is helping you. If the sterile sheet is “contaminated” we may need to start again.
Your doctor will then numb the groin area with some local anaesthetic. A needle is then used to access the femoral artery which is the easiest point of introduction for the catheter. The only sensation you will feel is a pinprick when the local anaesthetic is injected and a little pushing when a sheath is inserted into the femoral artery.
Your doctor will then insert a catheter (a thin tube) into the blood vessels and manoeuvre to the point where the coronary arteries arise. The doctor then manipulates the catheter to engage the beginning of the coronary artery (first the left and then the right) and then a small amount of contrast (X-ray dye) is injected to outline the artery. A sophisticated X-ray machine is used to take a short movie picture of the artery during this injection. The machine is moved into a number of different projections to take multiple pictures to ensure that every area of the artery (which is like a tree-like structure with many branches) is visualised.
The catheter needs to be changed to a different shape to engage the right coronary artery and then a few pictures in different views. When the X-ray machine moves it can come quite close but will not hurt you. Finally a third catheter is introduced, which is manipulated inside the heart’s main pumping chamber—the left ventricle. An injection of contrast is then performed to assess the function of the heart muscle. This is when you may feel a hot flush which starts in your chest and moves up to your head and then down to your backside. The contrast causes this feeling which will pass after about 20 seconds.
The catheter is then removed and firm pressure is applied to the puncture site for 15 mins to stop any bleeding until the artery puncture is sealed. The cardiologist will then assess your pictures and decide on the next appropriate course of action. The options are:
- continue on medical treatment
- perform an angioplasty procedure
- refer you for open heart bypass or valve surgery.
Your hospital stay will usually be overnight or sometimes your cardiologist may perform the procedure as a same day procedure.