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In 1980 the U.S. Food and Drug
Association approved the use of aspirin to help reduce
the risk of stroke after a transient ischemic attack
(TIA) - a mini stroke. (For the warning signs of TIA
click here.)
The FDA's followed a Canadian study
that discovered that aspirin reduced the risk of subsequent
TIA by 19 percent and the risk of a second stroke by
31 percent. The study concluded that aspirin was effective
in reducing the incidence of threatened stroke.
The most common form of stroke is
caused when a blood vessel that supplies the brain with
oxygen and nutrients becomes blocked by a blood clot.
There are two types of this clot-induced
stroke:
A cerebral thrombosis occurs when
a blood clot forms around a blood-vessel deposit (known
as a thrombus) in a vessel that serves the brain. When
the clot grows too large, it blocks the flow of oxygen
and nutrients to the brain, inducing a stroke. This
type of stroke is the most common and often occurs in
arteries damaged by atherosclerosis.
A cerebral embolism occurs when a
blood clot forms in the body (known as a embolus), usually
in the heart, and travels through the blood stream to
the brain. Once in the brain, the blood clot will lodge
itself in a smaller blood vessel and block the flow
of blood.
Aspirin plays a key role in helping
lessen the chances of these two types of stroke from
occurring by blocking platelets from producing the prostaglandin
thromboxane, which is critical in the clotting action
of blood.
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