What are the coronary arteries and why are they important?
Nutrition and energy are delivered to your entire body by blood from the pumping heart. The heart itself requires constant energy and blood flow delivered by coronary arteries.
What happens when coronary artery blood flow is reduced?
A blockage in the coronary arteries prevents blood flow and causes the heart muscle to starve. The medical term for such starvation is ischemia, most often causing chest discomfort, called angina.What if coronary blood flow is severely reduced?
If the blockage is severe, some of the heart muscle actually dies. When heart muscle dies, this is called a heart attack, or myocardial infarction. Think of the coronary artery as a drinking straw. If something gets stuck inside the straw, drinking becomes difficult. If the straw is completely blocked, drinking is impossible. The same thing happens to blood flow when a blockage occurs inside a coronary artery.
What is atherosclerosis (plaques) and what causes it?
We are born with coronary arteries free of all blockage. As we age, our lifestyle may cause the arteries to harden and their insides to become narrowed by plaques. Plaques grow on the inside wall of arteries and are composed of cholesterol and other material that builds-up over time (atherosclerosis).
When do stable plaques cause angina?
Blood flow through a coronary artery may be limited by a plaque but still sufficient for the heart when the body is at rest. However, when the body’s demand for blood supply increase, as with exercise or emotional stress, the coronary blood flowing past the plaque is not enough. Angina occurs in those with stable plaques when the body’s demand is greater that the heart’s supply.
When do plaques become unstable, and what happens?
An unstable plaque can “rupture” and release cholesterol and other substances into the blood. The released elements make the blood think that there is damage and bleeding from the coronary artery. The body reacts to this damage by trying to form a blood clot (sudden intravascular thrombosis). Unfortunately, this clot inside the artery blocks blood flow and can cause a heart attack.
What can happen to me if I have an unstable plaque?
Acute coronary syndromes (ACS) are several conditions that result from unstable plaque. The spectrum of ACS starts with the least severe, unstable angina, and ends with a severe type of heart attack, called an ST elevation myocardial infarction.
Does everyone get blockages in their coronary arteries?
No, some people never do. However, most people in the United States have a diet full of cholesterol and fats which cause blockages (atherosclerosis). A diet of high cholesterol and fats along with high blood pressure, diabetes, smoking, and obesity can contribute to formation of coronary plaques and coronary artery disease (CAD). Additionally, family history of CAD and old age significantly increase your risk of CAD. Studies of young men killed in the Korean War revealed that many of them had CAD and never knew it. The coronary blockages in these young men were minor, called fatty streaks, or fat deposits of cholesterol on the inside of a coronary artery. The fatty streaks often grow and develop into plaques. As a plaque grows it begins to block, or obstruct, the inside of the coronary and eventually can lead to angina.
If I have angina, will I also have a heart attack?
No, most people never have the plaque rupture and severe blockage which causes a myocardial infarction. It’s not clear which plaques will cause heart attacks.