Smoking and Coronary Artery Disease

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Smoking and Coronary Artery Disease

Topic Overview

Quitting smoking is probably the most important step you can take to decrease your chance of coronary artery disease (CAD) and a heart attack.

If you smoke, you are 2 to 4 times more likely to get heart disease. And you are 2 to 3 times more likely to die from heart disease.1

Carbon monoxide, nicotine, and other substances in tobacco smoke can promote atherosclerosis and trigger symptoms of coronary artery disease. Smoking:

  • Causes the platelets in your blood to clump together easily by making your blood cells more "sticky" and more likely to form clots. Clumping platelets can then block your coronary arteries and cause a heart attack.
  • Can cause spasms in your coronary arteries, which can reduce the blood flow to your heart in a way similar to that of atherosclerosis.
  • Can trigger irregular heartbeats (arrhythmias).
  • Lowers "good" cholesterol (high-density lipoprotein, or HDL). Cholesterol-carrying lipoproteins also more easily enter the walls of your arteries, where they can develop into a hard plaque and atherosclerosis.
  • Reduces the amount of oxygen that can be carried by red blood cells in the bloodstream.

People who smoke are more likely to develop angina, have a heart attack, and die from some form of heart disease.

Smoking also affects those around you. Second-hand smoke may increase other people's risk of coronary artery disease.

What are the benefits of quitting smoking?

Your risk of developing CAD drops relatively soon after you quit smoking. After your first year of not smoking, your risk of heart disease decreases by half. Also, your risk of having a heart attack decreases when you stop smoking.

When you quit smoking, you cut your risk of death even more by staying away from cigarettes for good. After 15 years of not smoking, your risk of death from heart disease is the same as if you had never smoked at all.

If you have had angioplasty or coronary artery bypass graft surgery to repair narrowed or blocked arteries, quitting smoking can decrease the risk of those arteries narrowing again. Your doctor will urge you to quit smoking so you get the most benefit from these procedures.

How do I quit smoking?

Quitting smoking is not easy. Many people have to try several times before they succeed. There are several methods for quitting smoking that have proven successful for thousands of people. Ask your doctor about nicotine replacement therapy (patches or gum that controls your nicotine craving), classes, and counselling. One of the secrets to quitting smoking is not to lose your determination to quit, even if you don't succeed right away.

For more information, see the topic Quitting Smoking.



  1. Lloyd-Jones D, et al. (2009). Heart disease and stroke statistics 2010 update: A report from the American Heart Association. Circulation. Published online December 17, 2009 (doi: 10.1161/circulationaha.109.192667). Also available online:


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer John A. McPherson, MD, FACC, FSCAI - Cardiology
Last Revised August 23, 2010

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