Coronary Artery Disease

Normal coronary arteries There are two main coronary arteries that arise from the aorta to supply the heart, the left and the  right. The left main stem coronary artery splits into two major branches, and the blood supply of the heart is therefore thought of as having three main territories:

1. The left anterior descending territory (sometimes referred to as the anterior territory meaning the front of the heart) 

2. The circumflex territory (also known as the lateral circulation, meaning the side of the heart) 

3. The right coronary territory (or inferior territory, meaning the bottom of the heart). 

Because there are three main territories, when all of them are affected, a triple-bypass is the most common surgery to get a good blood supply to all areas of the heart. However, as well as the main blood vessels named above,  there are other named branches that run over the surface of the heart. If more than one of these are affected, more bypass grafts might be required.

Atherosclerosis

Atherosclerosis (sometimes also known as arteriosclerosis, coronary artery disease or ischaemic heart disease) is a serious condition where arteries gradually become narrowed due to furring up of the tube with fatty deposits called plaques.

As the size of the tube is narrowed by the disease, less blood is able to be transported through the blood vessel to the organ that is is supplying, eventually starving it of oxygen and nutrients. 

If there is a sudden or severe narrowing of the coronary arteries (for example, if your plaque bursts, or the heart is working very hard and the blood supply is insufficient for it), the muscle can be starved of oxygen for long enough for it to be damaged or die. This is called a myocardial infarction or MI and it is an emergency.

Angina

When the heart muscle is starved of oxygen because of narrowing of the coronary arteries, it develops pain called “angina”. This is like the cramp that you might have in your legs from running for a long time. It’s not always very obvious what is angina, but it is often described as:

• * a dull ache or heaviness across the chest 
   
• * like someone sitting on your chest
   
• * a tight band around your chest
   
• * feelings like indigestion
   
• * tightness in the jaw, shoulders or arms

It can sometimes also be a shortness of breath or a sharp pain, but these are much less common and if you describe these pains, there may be other explanations.

Your doctors will note the timing, frequency and intensity of the pains, along with things that make it better or worse. Further tests are sometimes necessary to distinguish between angina and other symptoms.

Risk factors

There are a number of important risk factors associated with coronary artery disease:
 

• * High blood pressure (hypertension)
   
• * High cholesterol (hypercholesterolaemia)
   
• * Smoking
   
• * Genetics (a history of similar problems in the family)
   
• * Diabetes

If you have atherosclerosis in your coronary arteries, there is a chance that you may have the same disease process in other arteries such as those to your head, other organs or limbs. These can increase the chances of strokes, organ problems or peripheral vascular disease. 

Treatments

Prevention is better than cure. 

Coronary artery disease can be treated in a number of ways. The best way to “treat” coronary artery disease is to prevent it in the first place. The NHS website (https://www.nhs.uk/conditions/cardiovascular-disease/) has recommendations on how you can achieve this, including: 

• * avoiding smoking
   
• * eating a balanced diet
   
• * taking regular exercise
   
• * maintaining a healthy weight
   
• * having your blood pressure and cholesterol kept in check
   
• * ensuring that, if you are diabetic, you take any medications to keep your sugars well controlled

If you have already developed coronary artery disease, there are three main treatment strategies that can be used, depending on how severe and extensive your disease is. There are specific guidelines that dictate who ought to have medical management, who should have stents and who should be offered surgery.

The basis of these decisions is scientific evidence that informs doctors as to which treatment is most likely to give you the longest and best quality of life. In every case, you should get the opportunity to discuss your management.

Medical management

Once fatty deposits have accumulated in your coronary arteries, they are difficult to get rid of. Most medications for coronary artery disease will aim to reduce the progression of atherosclerosis or to ensure that any narrowings in plaques do not suddenly rupture or become unstable. Some medications will try to keep the blood vessels relaxed (or “dilated” to maximise the amount of blood flowing to the heart). 

The medicines used include:

• * Antiplatelets (aspirin, clopidogrel, prasugrel, ticagrelor etc) which help to thin the blood so that it doesn’t clot off in the narrowed blood vessels 
   
• * Statins (simvastatin, atorvastatin, rosuvastatin, pravastatin etc) which try and block the formation of cholesterol and remove LDL cholesterol from the blood.
   
• * Beta-blockers (atenolol, bisoprolol, nebivolol etc) which slow the heart rate down, reduce high blood pressure and prevent angina 
   
• * Nitrates (which come in many different forms, including sprays, tablets to dissolve under the tongue, quick action tablets, slow release tablets and patches to stick on the skin). These help to open up the coronary arteries and relieve angina. 
   
• * Angiotensin converting enzyme (ACE) inhibitors (rampiril, enalapril, perindopril etc) and Angiotensin II receptor antagonists (such as candesartan, valsartan etc) reduce the blood pressure and can help the heart to grow stronger. 
   
• * Calcium channel blockers (amlodipine, nifedipine, verapamil, diltiazem) treat hypertension and also open up the arteries. 

Percutaneous Coronary Intervention (PCI)

PCI is sometimes known as angioplasty, stenting or percutaneous transluminal coronary angioplasty (PTCA). If it is required in an emergency due to a particular form of heart attack (not all heart attacks require PCI), then it is also known as primary PCI or PPCI.

This procedure is usually done awake lying on a table with an x-ray machine to assess the coronary arteries using a dye injected through a needle in the wrist or groin. 

The process of taking pictures of the coronary arteries is called coronary angiography (or a coronary angiogram) and any treatments offered through this route (such as opening up the arteries with a balloon or stent) are called angioplasty.

Coronary Artery Bypass Grafting (CABG)

Coronary Artery Bypass Grafting or CABG (pronounced like “cabbage”) is also sometimes just known as “bypass surgery”, “heart bypass”, or “coronary artery bypass surgery”. 

Once an angiogram has been performed to assess the coronary arteries, the cardiologist undertaking the procedure will make an assessment as to which form of treatment is best suited to you. If there is any uncertainty, the angiogram pictures are discussed at a meeting of cardiologists and surgeons (called a Multi-Disciplinary Team (MDT) meeting) in order to get agreement as to what would be the best treatment. These discussions take into account your general health, how bad your symptoms are, how likely you are to recover well from the treatments being offered and what your personal preferences are.