In my previous article, I discussed some of the heart problems that occur and how they can be treated. Today, I want to talk about one particular type of heart problem that today is the leading cause of death in developing and developed countries.

To survive and function properly, every part of the human body needs ‘cleaned’ blood full of oxygen and nutrients. This blood is pumped out by the heart and sent all over the body through tubes called arteries. And the heart also needs this oxygen and nutrient rich blood to function. The arteries supplying blood to the heart are called coronary arteries.

Any and all arteries in the body can over time develop blockages. In bigger arteries these blockages can produce problems over time but in the much smaller arteries of the heart, these blockages can produce problems much sooner. To put things in perspective, the biggest heart artery is about the size of a lead pencil. However, the most important branches of these big arteries that bring blood to the vital heart muscles may be no larger than the lead in that pencil.

There are two major arteries that supply blood to the heart. The Right Coronary Artery (RCA) that supplies mostly the right side and the under-part of the heart. And the left artery called the Left Main Artery (LM). The left main artery gives two major branches, the Left Anterior Descending artery (LAD) that supplies the front and the circumflex coronary artery and its Obtuse Marginal (OM) branches that supply the left side of the heart.

So, from a medical point of view, we say that the heart is supplied by three main arteries and their branches. And when all these three, the RCA, the LAD, and the OM are involved it is called three vessel disease. The next big question is why do these arteries become narrowed or get blocked up. One of the major research efforts in modern medicine has been devoted to answering this question. Interestingly, we have no good answers after expending billions of dollars except that in time it will all come down to management of human genetics.

Read also: Heart disease-I

What we do know is that the human arteries including the arteries of the heart are made up of three layers of thin tissue and that for some reason fat starts getting deposited between the innermost layer and the middle layer. As the fat gets deposited, the inner layer of the artery starts to bulge inwards into the lumen of the artery. This leads to progressive decrease in the inside diameter of the tube like artery eventually producing an increasing obstruction to the flow of blood. Just think of the bathroom tap where the pipe leading to it gets clogged and one day when you open the tap nothing comes out. Obviously the clog happened over a period of time. More about this a bit later.

So like most diseases that happen without any externally obvious reasons, the causes of heart artery blockages can be divided into two broad categories. First are bad genes. The fact that either or both parents had heart artery blockages at a young age (fifties and sixties) increases the risk for the child to have the same problem at a similar age. Diabetes and high blood pressure are two other conditions that can be inherited and they also increase the risk of developing artery blockages. The role of genetics in having moderately high blood level of fats (cholesterol) in the general population is limited except in certain inherited types of very high blood cholesterol levels.

After bad genes we come to bad habits. Of these at the top are overeating leading to obesity, smoking cigarettes, and the lack of physical activity. Drinking excessive amounts of alcohol is a bad habit for many reasons but not for causing narrowing of the heart arteries. Whether diet except when too heavily made up of fatty-foods has a direct effect on developing artery blockages is questionable. What then happens when heart arteries start getting blocked?

As I said above, even the heart also needs the blood it pumps out for the rest of the body. Once the amount of available blood starts to decrease then a cascade of events occurs. If the heart is forced to increase its work, the heart protests. The protest is through pain, pressure, ache or just a feeling of general discomfort in the area around the heart during exertion. This painful feeling is called angina pectoris. Classic angina starts with increased physical activity and subsides when the activity is stopped.

Read also: Heart disease-III

As the blockages get worse chest pain occurs even when the person is not doing any physical activity. Of course even when we are resting or sleeping the heart is still working pretty hard supplying blood to the entire body. This sort of angina that occurs even at rest is often a prelude to what is called a heart attack. What that means is that a part of the heart muscle is starting to die because it is not getting any blood at all and that the artery blockage is probably complete. Heart attacks are what kill people.

The idea then is to prevent heart attacks. The prevention of heart attacks includes first the prevention of any level of artery blockages. Decreasing the chance of getting heart artery blockages-coronary artery disease (CAD) is simple. Choose your parents wisely, stop smoking, start running for a few hours every day, eat only vegetables and do not become fat. And if you have medical problems like high blood pressure or diabetes, get them treated properly.

If symptoms of CAD still appear then treatment must be started. Treatment of CAD is divided into three types. First is the medical treatment, then come catheter based treatment (angioplasty/stents) and then there is surgery (Coronary Artery Bypass Grafting-cabbage). I will leave angioplasty/stents and cabbages for the next time.

Before treatment some tests must be done to make sure that CAD exists. These tests include ‘stress’ tests, coronary catheterisation, special X-Rays (CT Angio) and many different types of scans. Medical treatment is based on medicines that decrease the amount of work the heart has to do. Added to these medicines over the last few decades are some special medicines called ‘statins’ that decrease the amount of bad cholesterol in the body and so prevent the blockages from getting worse. Most patients with known CAD are also placed on Aspirin.

Heart attacks occur most often because the fat deposits under the inner lining of coronary arteries that I mentioned above suddenly enlarge and poke a hole in the artery. The inner lining of all our arteries and veins are like the Teflon coating in our non-stick cooking pans. Nothing sticks to the pan unless the Teflon is scratched. And the circulating blood does not stick to the inside of the arteries unless the inner lining is scratched or damaged. Damage to this inner lining makes the blood clot and stick to the inside blocking the artery completely. Aspirin by thinning the blood decreases the chance that blood will clot and by doing that can prevent a heart attack.