Coronary artery disease
Arteries are blood vessels that carry oxygen-rich blood away from your heart, to all of the tissues of your body — including your heart itself.
Healthy arteries — including healthy coronary arteries — are clean, smooth and slick. The artery walls are flexible and can expand to let more blood through when necessary. Artery disease is thought to begin with an injury to the lining of the walls of arteries. This injury makes them susceptible to atherosclerosis.
Atherosclerosis is the slow, progressive buildup of deposits called plaques on the inner walls of your arteries. Plaques are deposits of fat, cholesterol, calcium and other cellular material from your blood.
These plaques both narrow and harden arteries. Plaques alone can significantly block your coronary arteries and arteries throughout your body. They can also become fragile and rupture, forming blood clots that can block blood flow to your heart or elsewhere in your body.
Atherosclerosis is a complex disease that starts in childhood and usually progresses as you age. In some people, atherosclerosis progresses rapidly, especially those with risk factors such as smoking, high blood pressure, diabetes and high cholesterol. Obesity and physical inactivity are other factors that can contribute to this disease.
A high blood level of low-density lipoprotein (LDL) cholesterol — so-called "bad" cholesterol — can lead to atherosclerosis. High blood cholesterol can be an inherited problem, but it's also typically a byproduct of poor health habits — such as eating a high-fat, high-cholesterol diet, which is common in Western societies. When the level of LDL cholesterol in your blood is high, there's a greater chance that it will be deposited onto your artery walls. Higher levels of the "good" cholesterol, high-density lipoprotein (HDL), seem to protect against heart disease.
Some research suggests that a bacterium, such as Chlamydia pneumoniae, may play a role in the narrowing of coronary arteries. But whether infectious agents play an important role in this process isn't well-defined because other research has failed to confirm this link. It's also unclear whether inflammation of the arteries caused by an infection or other factor underlies coronary artery disease or accelerates it.
Several factors place you at added risk of coronary artery disease. Some of these you can control, and some you cannot.
Uncontrollable risk factors for coronary artery disease include:
The major controllable risk factors for coronary artery disease include:
Not everyone who has coronary artery disease has classic risk factors, such as high cholesterol or high blood pressure. So, researchers are looking for other risk factors that may play a role in the development of coronary artery disease. Research is ongoing, but currently some likely suspects are: C-reactive protein, homocysteine, fibrinogen and lipoprotein (a).
Risk factors often occur in clusters and may feed one another, such as obesity leading to diabetes and high blood pressure. Even a small increase in one becomes more critical when combined with others.
Certain risk factors, when coupled together, put you at an even greater risk for coronary artery disease. Metabolic syndrome is a cluster of risk factors known to greatly increase your risk of heart disease. Also known as syndrome X, metabolic syndrome includes obesity, especially with abdominal fat, abnormal cholesterol levels, high blood pressure and insulin resistance.