Coronary artery disease is
caused by hardening of the arteries, or
atherosclerosis . This means that fatty deposits called plaque
build up inside the arteries. Arteries are the blood vessels that carry
oxygen-rich blood throughout your body.
Atherosclerosis can affect any
arteries in the body. When it occurs in the arteries that supply blood to the
heart (the coronary arteries ), it is called coronary artery disease.
To understand why plaque and atherosclerosis is a problem, compare a healthy artery with an artery with atherosclerosis:
A healthy artery is like a rubber tube. It is smooth and flexible, and blood flows through it freely. When your heart has to work harder, such as when you exercise, a healthy artery can stretch to let more blood flow to your body's tissues.
An artery with atherosclerosis is more like a clogged pipe. Plaque narrows the artery and makes it stiff. This limits the flow of blood to the tissues. When the heart has to work harder, the stiff arteries can't flex to let more blood through, and the tissues don't get enough blood and oxygen.
When plaque builds
up in the coronary arteries, the heart doesn't get the blood it needs to work
well. This is called ischemia (say "is-KEE-mee-uh"). Ischemia can cause symptoms such as chest pain or pressure. Over time, ischemia can weaken or damage the heart.
If a plaque tears, the
body tries to fix the tear by forming a blood clot around it. The clot can
block blood flow to the heart and cause a heart attack .