Your heart is a strong muscular pump. It is responsible for pumping about
3,000 gallons of blood throughout your body every day. Like other muscles in
your body, your heart needs to receive a good supply of blood at all times to
function properly. Your heart muscle gets the blood it needs to do its job from
the coronary arteries.
What is coronary artery disease?
Coronary artery disease is the narrowing or blockage of the coronary
arteries caused by atherosclerosis. Atherosclerosis (sometimes called
"hardening" or "clogging" of the arteries) is the buildup of cholesterol and
fatty deposits (called plaque) on the inner walls of the arteries that restricts
blood flow to the heart.
Without adequate blood, the heart becomes starved of oxygen and the vital
nutrients it needs to work properly. This can cause chest pain called angina.
When one or more of the coronary arteries are completely blocked, a heart
attack (injury to the heart muscle) may occur.
What causes the coronary arteries to narrow?
Your coronary arteries are shaped like hollow tubes through which blood can
flow freely. The walls of the coronary arteries are normally smooth and elastic.
Coronary artery disease starts when you are very young. Before your teen
years, the blood vessel walls begin to show streaks of fat. As you get older,
the fat builds up, causing slight injury to your blood vessel walls.
In an attempt to heal the blood vessel walls, the cells release chemicals
that make the blood vessel walls stickier.
Other substances traveling through your blood stream, such as inflammatory
cells, cellular waste products, proteins and calcium, begin to stick to the
vessel walls. The fat and other substances combine to form a material called plaque.
Over time, the inside of the arteries develop plaques of different sizes.
Many of the plaque deposits are soft on the inside with a hard fibrous "cap"
covering the outside. If the hard surface cracks or tears, the soft, fatty
inside is exposed. Platelets (disc-shaped particles in the blood that aid
clotting) come to the area, and blood clots form around the plaque. This causes the artery to narrow even
more.
Sometimes, the blood clot breaks apart, and blood supply is restored. In other cases, the blood clot (coronary thrombus) may suddenly block the blood supply to the heart muscle (coronary occlusion), causing one of three serious conditions, called acute coronary syndromes.
What are acute coronary syndromes?
Unstable angina: This may be a new symptom or a change from stable angina. The angina may occur more frequently, occur more easily at rest, feel more severe, or last longer.
Although this can often be relieved with oral medications, it is unstable and
may progress to a heart attack. Usually a more intense medical treatment or a
procedure is required to treat this acute coronary syndrome.