blood clot in an unbroken blood vessel?

blood clot in an unbroken blood vessel causes stokes and clogs the blood vessel which means if it happens in the brain, then it will result in a stroke.
my question is:
WHY DOES IT HAPPEN? WHY DO BLOOD CLOT SUBSTANCES FORM IN UNBROKEN BLOOD VESSELS?

jazzy2008-01-19T23:33:22Z

Favorite Answer

simple.... due impaired plasminogen activity or sometimes accumulation of cholesterol on these clots resulting in formation of plague in the blood vessels... ands thats why tissue plasminogen is injected to the patients in order to prevent the blood from clotting....

mr.answerman2008-01-19T23:27:02Z

It can happen for unknown reasons, the term is idiopathic. Or it can be from smoking, or atherosclerosis. Or a fatty build up in the vessel can trigger a clot and even a piece that can break off and cause an embolism.