The coronary arteries run along the coronary sulcus of the myocardium of the heart. Their main function is to supply blood to the heart. This is a crucial function for myocardial function and subsequently homeostasis of the body. The arrangement of coronary arteries varies among people significantly.
Structure and Function
There are two primary coronary arteries, the right coronary artery (RCA) and the left main coronary artery (LMCA). Both of these originate from the root of the aorta. The RCA emerges from the anterior ascending aorta and supplies blood primarily to the right atrium, right ventricle. The sinoatrial nodal artery is a branch of the RCA that supplies the SA node.
The RCA also supplies the AV node via a septal perforating branch in 90% of people.
 The RCA then classically descends into smaller branches including the right posterior descending artery (PDA) and acute marginal artery. The posterior descending artery is responsible for blood supply to the posterior one-third of the interventricular septum. The left anterior descending artery (LAD) supplies the anterior two-thirds of the septum.
 The LAD is one of two major branches of the LMCA, with the other being the left circumflex (LCx) coronary arteries. Combined, these two supply blood to the left atrium and left ventricle. The circumflex artery is responsible for blood supply to the left atrium and the posterior-lateral aspect of the left ventricle while the LAD supplies blood to the anterior portion of the left ventricle. Other small branches of the coronary arteries are the obtuse marginal artery (OMA), diagonals, and septal perforator (SP).
A coronary angiogram is a special procedure that takes dynamic X-ray pictures of your heart. The purpose of this procedure is to see if your coronary arteries are narrowed or blocked and to look for abnormalities in your heart muscle or heart valves. Another term for a coronary angiogram is cardiac catheterization.
The test is done in a special laboratory called a cardiac catheterization laboratory (cath lab), which is similar to an operating theatre.
A slender catheter (a thin, hollow plastic tube) is threaded through the largest artery in your body (the aorta) via the wrist or the groin artery until it reaches the coronary arteries of the heart. A special X-ray-sensitive dye (contrast) is injected and dynamic X-rays are taken of the blood vessels as the contrast moves through them.
Problems diagnosed by coronary angiogram
Apart from diseased coronary arteries, an angiogram can also diagnose a range of heart problems including aneurysms (abnormal ballooning of the heart wall), heart arrhythmias (irregular heartbeat) or birth defects, such as a hole in the heart
Medical issues to consider before having an angiogram
Before the procedure, you need to discuss a range of issues with your doctor including:
Your medical history, including whether or not you have asthma, allergies or kidney disease
If you have experienced allergic reactions to any drugs or any current medications you are taking. You may need to discontinue certain medications before the test, such as medications that thin the blood
Fasting – you need to fast four to six hours prior to your test other tests – you may undergo various tests before the angiogram, including blood tests, an electrocardiogram and chest x-ray, and cardiac CT (computed tomography).
Coronary angiogram procedure
Most diagnostic coronary angio procedures are done as day cases. That means that you are in and out of hospital within one day. Before the procedure, a nurse will take your medical history and you will change into a hospital gown. The nurse will prepare you for the procedure by putting in an IV cannula and shaving both sides of your groin and wrist if necessary.
Once in the cath lab, you will lie on a special table. A heart monitor will record your heartbeat during the test. The skin on your wrist and both sides of your groin is cleaned with an antiseptic wash and you are covered with sterile drapes.
The doctor injects a small amount of local anesthetic around the access site (wrist or groin) to numb the area then inserts a small catheter through the skin into the blood vessel. The doctor watches the progress of the catheter via dynamic X-rays transmitted to a television monitor.
You can’t feel the catheter going through the heart because there are not enough nerves in the blood vessels. Once the catheter is in place, a small amount of contrast (x-ray-sensitive dye) is injected through it. Further dynamic X-rays are taken as the contrast goes through the blood vessels. You may feel a warm flush or tingling as the contrast is injected. The angiogram lasts for around 40 minutes.
Immediately after the coronary angiogram
After a coronary angiogram, Your blood pressure, pulse, breathing, and wound site are regularly checked and recorded.
You may be given intravenous fluids for a short time, although you will be encouraged to eat and drink as soon as you feel able.
You may be allowed to sit up after four hours.
You may be discharged to go home up to six hours post (after) recovery.
If you are not already on a special diet, you will be encouraged to adopt a cholesterol-lowering diet.
Initial results are given to you by the cardiologist who performed the procedure.
You may have to make follow-up appointment with a cardiologist to further discuss your treatment
Complications of a coronary angiogram
Some of the possible complications of a coronary angiogram include:
Allergic reaction to the contrast dye, including hives and itchy skin
Bleeding from the wound
Taking care of yourself at home after a coronary angiogram
Be guided by your doctor, but general suggestions include:
Try to rest as much as you can.
Avoid standing for more than a few minutes at a time.
Avoid heavy lifting for at least a week after the procedure.
See your doctor if you suspect an infection.
Symptoms include redness
discharge from the wound site.
Drink plenty of fluids eight hours after the procedure (unless told otherwise by your cardiologist) to help flush the contrast from your body.
Long-term outlook after a coronary angiogram
You will need to make another appointment with your doctor to discuss the results of your angiogram. Treatment depends on the diagnosis.
Narrowed coronary arteries may possibly be treated during the angiogram by a technique known as angioplasty. A special catheter is threaded through the blood vessels and into the coronary arteries to remove the blockage.
Another surgical option for severely narrowed coronary arteries is a bypass operation. This involves transplanting veins and arteries from other parts of your body to your heart.