Another very useful link describing Aspirin and it's uses... 
" Cardiovascular disease includes previous heart attack, ischemic stroke (a stroke due to a lack of blood flowing to the brain), angina (chest pain due to decreased blood flow to the heart), coronary artery bypass graft surgery, angioplasty, or transient ischemic attack (a brief blockage of blood flow to the brain that is usually a warning sign of a future stroke)."
http://patients.uptodate.com/topic.asp?file=hrt_dis/2908