How do arteries become blocked?

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

The arteries can become blocked through a build up of plaque on the insides of the arteries, resulting in coronary artery disease, or CAD. Watch this animation to see how this can happen.

Arteries can be blocked by three problems, which may occur alone or in combination to produce a heart attack:

  • Fatty buildup in the artery (atherosclerosis)
  • A blood clot in an artery already narrowed by atherosclerosis
  • A spasm of the artery's muscular wall.

Without enough blood and oxygen, the heart muscle begins to die.

Blocked arteries can cause heart attacks, strokes and other serious problems. But what exactly goes wrong? How do arteries become blocked to begin with?

Each artery is made up of three layers: a smooth layer on the inside, a thick layer of muscle in the middle and a rough layer on the outside. Your arteries are strong and flexible, but they can become less effective over time. The smooth inner lining of the artery can become damaged, causing a substance called plaque to buildup or blood to start clotting at the injury site. Plaque is made up of fat, cholesterol, calcium and scar tissue. The risk of plaque formation in the arteries is increased by several factors:

  • Saturated fats and trans fats in the diet
  • Cholesterol in the diet
  • Diabetes
  • High blood pressure (hypertension)
  • Genetics (family history)
  • Smoking

Plaque and blood clots inhibit blood flow in the arteries and can ultimately stop or block it altogether. Controlling risk factors such as diet can help stop, slow or sometimes even reverse the blockage of arteries.

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