How Cigarettes Increase the Risk of Heart Attack and Stroke.

Most heart attacks and many strokes are the result of fat and cholesterol deposits in the arteries of the heart and the brain.  Some of these fat and cholesterol deposits within the walls of the blood vessel later disrupt abruptly leading to the closure of the artery.  If  an artery of significant size closes off in the heart, a heart attack occurs which results in death of some of the heart muscle.  If an artery of the brain closes off,  a stroke occurs.

Cigarette smoking increases the risk of heart attack and stroke through the following means:

• Smoking irritates  the lining of the vessel wall.  This makes it easier for fat and cholesterol to deposit within the wall of the artery. A blockage of fat and cholesterol then develops more easily in the setting of smoking

• Smoking causes blood vessels to constrict temporarily through muscular contraction of the vessel wall.  For a normal vessel this is usually tolerated.  However, for a blood vessel that has a significant fat and cholesterol blockage, the constricting effect of smoking on the vessel wall can lead to further lack of blood flow.

• Platelets are small protein components that are in blood which play a major role in blood clotting.  Platelets normally help the blood clot when a person develops a cut and avoid bleeding profusely.  Smoking makes the platelets in the blood excessively  "sticky".  This increases the likelihood that a blood vessel will close off and clot inappropriately. This can cause a heart attack or stroke.