Fatty Deposits in the Coronary Arteries Starve the Heart of Oxygen

1. The coronary arteries branch off the aorta and supply the heart muscle with oxygen-rich blood for respiration.
2. In coronary heart disease, layers of fatty material build up inside these arteries.
3. This narrows the arteries and reduces blood flow, so the heart muscle receives less oxygen.
4. Partial blockage can cause chest pain, and complete blockage stops oxygen reaching part of the muscle, causing a heart attack.

CHD Is a Non-Communicable Disease Treated by Doctors, Not Antibiotics

1. CHD is non-communicable: it is not caused by a pathogen and cannot be passed from person to person.
2. It develops slowly over many years and is linked to lifestyle, so it cannot be cured with antibiotics.
3. Instead, doctors treat CHD by widening the narrowed arteries, lowering blood cholesterol, or replacing faulty parts of the heart.

Stents Hold the Narrowed Arteries Open

1. A stent is a small mesh tube inserted into a narrowed coronary artery.
2. It is carried in on a tiny balloon, which is inflated to widen the lumen and then removed, leaving the stent to hold the artery open.
3. This increases blood flow to the heart muscle and lowers the risk of a heart attack.
4. Advantages of stents
   1. They widen the lumen and restore blood flow, so they are effective at reducing the risk of a heart attack.
   2. Inserting one is only minor surgery, and stents last a long time.
5. Disadvantages of stents
   1. A blood clot (thrombosis) can form on the stent.
   2. There is a risk of infection or damage to the blood vessel during surgery.

Statins Lower Blood Cholesterol

1. Statins are drugs taken regularly to reduce the level of cholesterol in the blood.
2. They lower harmful LDL cholesterol and slow the rate at which fatty material builds up, reducing the risk of CHD.
3. Advantages of statins
   1. They reduce fatty deposits and lower the risk of CHD, and can raise the level of beneficial HDL cholesterol.
4. Disadvantages of statins
   1. They must be taken for life and take time to work.
   2. They can cause side effects such as muscle pain, and do not act instantly in an emergency.

Faulty Heart Valves Can Be Replaced

1. Heart valves keep blood flowing in one direction through the heart.
2. A valve can become stiff and not open fully, reducing the blood pumped out, or it can develop a leak so blood flows backwards.
3. Both faults make the heart less effective at pumping oxygenated blood around the body.
4. A badly faulty valve can be replaced by surgery with a biological or a mechanical valve.
5. Biological valves
   1. Taken from cows, pigs or human donors, they work well and rarely leak, but may wear out after about 12 to 15 years and can be rejected.
6. Mechanical valves
   1. They last a long time, but raise the risk of blood clots, so the patient must take anti-clotting drugs for life.

Severe Heart Failure May Need a Transplant or Artificial Heart

1. In heart failure, the heart can no longer pump properly, and a donor heart, or heart and lungs, may be transplanted.
2. Donor hearts are scarce and waiting lists are long, so an artificial heart made of metal and plastic can be used instead.
3. An artificial heart can keep a patient alive while they wait for a transplant, or rest a weakened heart so it can recover.
4. Donor transplant
   1. A real heart works normally, but donors are rare and the body may reject it, so lifelong drugs are needed to suppress the immune system.
5. Artificial heart
   1. It is available faster and is less likely to be rejected, but does not work as well as a real heart and raises the risk of blood clots and stroke.

Weighing Up the Treatments

1. No treatment is perfect, so the benefits must always be weighed against the risks.
2. Drugs such as statins are non-invasive but slow and must be taken for life, while surgery for a stent or valve carries risks of infection, bleeding and clots.
3. A transplant can give a normal heart but depends on a scarce donor and lifelong anti-rejection drugs.
4. The best choice depends on how ill the patient is, how easily the treatment can be accessed, and its long-term side effects.